// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2026 Meta Platforms, Inc. and affiliates. */
#include <linux/bpf.h>
#include <linux/btf.h>
#include <linux/bpf_verifier.h>
#include <linux/filter.h>
#include <linux/vmalloc.h>
#include <linux/bsearch.h>
#include <linux/sort.h>
#include <linux/perf_event.h>
#include <net/xdp.h>
#include "disasm.h"

#define verbose(env, fmt, args...) bpf_verifier_log_write(env, fmt, ##args)

static bool is_cmpxchg_insn(const struct bpf_insn *insn)
{
        return BPF_CLASS(insn->code) == BPF_STX &&
               BPF_MODE(insn->code) == BPF_ATOMIC &&
               insn->imm == BPF_CMPXCHG;
}

/* Return the regno defined by the insn, or -1. */
static int insn_def_regno(const struct bpf_insn *insn)
{
        switch (BPF_CLASS(insn->code)) {
        case BPF_JMP:
        case BPF_JMP32:
        case BPF_ST:
                return -1;
        case BPF_STX:
                if (BPF_MODE(insn->code) == BPF_ATOMIC ||
                    BPF_MODE(insn->code) == BPF_PROBE_ATOMIC) {
                        if (insn->imm == BPF_CMPXCHG)
                                return BPF_REG_0;
                        else if (insn->imm == BPF_LOAD_ACQ)
                                return insn->dst_reg;
                        else if (insn->imm & BPF_FETCH)
                                return insn->src_reg;
                }
                return -1;
        default:
                return insn->dst_reg;
        }
}

/* Return TRUE if INSN has defined any 32-bit value explicitly. */
static bool insn_has_def32(struct bpf_insn *insn)
{
        int dst_reg = insn_def_regno(insn);

        if (dst_reg == -1)
                return false;

        return !bpf_is_reg64(insn, dst_reg, NULL, DST_OP);
}

static int kfunc_desc_cmp_by_imm_off(const void *a, const void *b)
{
        const struct bpf_kfunc_desc *d0 = a;
        const struct bpf_kfunc_desc *d1 = b;

        if (d0->imm != d1->imm)
                return d0->imm < d1->imm ? -1 : 1;
        if (d0->offset != d1->offset)
                return d0->offset < d1->offset ? -1 : 1;
        return 0;
}

const struct btf_func_model *
bpf_jit_find_kfunc_model(const struct bpf_prog *prog,
                         const struct bpf_insn *insn)
{
        const struct bpf_kfunc_desc desc = {
                .imm = insn->imm,
                .offset = insn->off,
        };
        const struct bpf_kfunc_desc *res;
        struct bpf_kfunc_desc_tab *tab;

        tab = prog->aux->kfunc_tab;
        res = bsearch(&desc, tab->descs, tab->nr_descs,
                      sizeof(tab->descs[0]), kfunc_desc_cmp_by_imm_off);

        return res ? &res->func_model : NULL;
}

static int set_kfunc_desc_imm(struct bpf_verifier_env *env, struct bpf_kfunc_desc *desc)
{
        unsigned long call_imm;

        if (bpf_jit_supports_far_kfunc_call()) {
                call_imm = desc->func_id;
        } else {
                call_imm = BPF_CALL_IMM(desc->addr);
                /* Check whether the relative offset overflows desc->imm */
                if ((unsigned long)(s32)call_imm != call_imm) {
                        verbose(env, "address of kernel func_id %u is out of range\n",
                                desc->func_id);
                        return -EINVAL;
                }
        }
        desc->imm = call_imm;
        return 0;
}

static int sort_kfunc_descs_by_imm_off(struct bpf_verifier_env *env)
{
        struct bpf_kfunc_desc_tab *tab;
        int i, err;

        tab = env->prog->aux->kfunc_tab;
        if (!tab)
                return 0;

        for (i = 0; i < tab->nr_descs; i++) {
                err = set_kfunc_desc_imm(env, &tab->descs[i]);
                if (err)
                        return err;
        }

        sort(tab->descs, tab->nr_descs, sizeof(tab->descs[0]),
             kfunc_desc_cmp_by_imm_off, NULL);
        return 0;
}

static int add_kfunc_in_insns(struct bpf_verifier_env *env,
                              struct bpf_insn *insn, int cnt)
{
        int i, ret;

        for (i = 0; i < cnt; i++, insn++) {
                if (bpf_pseudo_kfunc_call(insn)) {
                        ret = bpf_add_kfunc_call(env, insn->imm, insn->off);
                        if (ret < 0)
                                return ret;
                }
        }
        return 0;
}

#ifndef CONFIG_BPF_JIT_ALWAYS_ON
static int get_callee_stack_depth(struct bpf_verifier_env *env,
                                  const struct bpf_insn *insn, int idx)
{
        int start = idx + insn->imm + 1, subprog;

        subprog = bpf_find_subprog(env, start);
        if (verifier_bug_if(subprog < 0, env, "get stack depth: no program at insn %d", start))
                return -EFAULT;
        return env->subprog_info[subprog].stack_depth;
}
#endif

/* single env->prog->insni[off] instruction was replaced with the range
 * insni[off, off + cnt).  Adjust corresponding insn_aux_data by copying
 * [0, off) and [off, end) to new locations, so the patched range stays zero
 */
static void adjust_insn_aux_data(struct bpf_verifier_env *env,
                                 struct bpf_prog *new_prog, u32 off, u32 cnt)
{
        struct bpf_insn_aux_data *data = env->insn_aux_data;
        struct bpf_insn *insn = new_prog->insnsi;
        u32 old_seen = data[off].seen;
        u32 prog_len;
        int i;

        /* aux info at OFF always needs adjustment, no matter fast path
         * (cnt == 1) is taken or not. There is no guarantee INSN at OFF is the
         * original insn at old prog.
         */
        data[off].zext_dst = insn_has_def32(insn + off + cnt - 1);

        if (cnt == 1)
                return;
        prog_len = new_prog->len;

        memmove(data + off + cnt - 1, data + off,
                sizeof(struct bpf_insn_aux_data) * (prog_len - off - cnt + 1));
        memset(data + off, 0, sizeof(struct bpf_insn_aux_data) * (cnt - 1));
        for (i = off; i < off + cnt - 1; i++) {
                /* Expand insni[off]'s seen count to the patched range. */
                data[i].seen = old_seen;
                data[i].zext_dst = insn_has_def32(insn + i);
        }
}

static void adjust_subprog_starts(struct bpf_verifier_env *env, u32 off, u32 len)
{
        int i;

        if (len == 1)
                return;
        /* NOTE: fake 'exit' subprog should be updated as well. */
        for (i = 0; i <= env->subprog_cnt; i++) {
                if (env->subprog_info[i].start <= off)
                        continue;
                env->subprog_info[i].start += len - 1;
        }
}

static void adjust_insn_arrays(struct bpf_verifier_env *env, u32 off, u32 len)
{
        int i;

        if (len == 1)
                return;

        for (i = 0; i < env->insn_array_map_cnt; i++)
                bpf_insn_array_adjust(env->insn_array_maps[i], off, len);
}

static void adjust_insn_arrays_after_remove(struct bpf_verifier_env *env, u32 off, u32 len)
{
        int i;

        for (i = 0; i < env->insn_array_map_cnt; i++)
                bpf_insn_array_adjust_after_remove(env->insn_array_maps[i], off, len);
}

static void adjust_poke_descs(struct bpf_prog *prog, u32 off, u32 len)
{
        struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab;
        int i, sz = prog->aux->size_poke_tab;
        struct bpf_jit_poke_descriptor *desc;

        for (i = 0; i < sz; i++) {
                desc = &tab[i];
                if (desc->insn_idx <= off)
                        continue;
                desc->insn_idx += len - 1;
        }
}

static struct bpf_prog *bpf_patch_insn_data(struct bpf_verifier_env *env, u32 off,
                                            const struct bpf_insn *patch, u32 len)
{
        struct bpf_prog *new_prog;
        struct bpf_insn_aux_data *new_data = NULL;

        if (len > 1) {
                new_data = vrealloc(env->insn_aux_data,
                                    array_size(env->prog->len + len - 1,
                                               sizeof(struct bpf_insn_aux_data)),
                                    GFP_KERNEL_ACCOUNT | __GFP_ZERO);
                if (!new_data)
                        return NULL;

                env->insn_aux_data = new_data;
        }

        new_prog = bpf_patch_insn_single(env->prog, off, patch, len);
        if (IS_ERR(new_prog)) {
                if (PTR_ERR(new_prog) == -ERANGE)
                        verbose(env,
                                "insn %d cannot be patched due to 16-bit range\n",
                                env->insn_aux_data[off].orig_idx);
                return NULL;
        }
        adjust_insn_aux_data(env, new_prog, off, len);
        adjust_subprog_starts(env, off, len);
        adjust_insn_arrays(env, off, len);
        adjust_poke_descs(new_prog, off, len);
        return new_prog;
}

/*
 * For all jmp insns in a given 'prog' that point to 'tgt_idx' insn adjust the
 * jump offset by 'delta'.
 */
static int adjust_jmp_off(struct bpf_prog *prog, u32 tgt_idx, u32 delta)
{
        struct bpf_insn *insn = prog->insnsi;
        u32 insn_cnt = prog->len, i;
        s32 imm;
        s16 off;

        for (i = 0; i < insn_cnt; i++, insn++) {
                u8 code = insn->code;

                if (tgt_idx <= i && i < tgt_idx + delta)
                        continue;

                if ((BPF_CLASS(code) != BPF_JMP && BPF_CLASS(code) != BPF_JMP32) ||
                    BPF_OP(code) == BPF_CALL || BPF_OP(code) == BPF_EXIT)
                        continue;

                if (insn->code == (BPF_JMP32 | BPF_JA)) {
                        if (i + 1 + insn->imm != tgt_idx)
                                continue;
                        if (check_add_overflow(insn->imm, delta, &imm))
                                return -ERANGE;
                        insn->imm = imm;
                } else {
                        if (i + 1 + insn->off != tgt_idx)
                                continue;
                        if (check_add_overflow(insn->off, delta, &off))
                                return -ERANGE;
                        insn->off = off;
                }
        }
        return 0;
}

static int adjust_subprog_starts_after_remove(struct bpf_verifier_env *env,
                                              u32 off, u32 cnt)
{
        int i, j;

        /* find first prog starting at or after off (first to remove) */
        for (i = 0; i < env->subprog_cnt; i++)
                if (env->subprog_info[i].start >= off)
                        break;
        /* find first prog starting at or after off + cnt (first to stay) */
        for (j = i; j < env->subprog_cnt; j++)
                if (env->subprog_info[j].start >= off + cnt)
                        break;
        /* if j doesn't start exactly at off + cnt, we are just removing
         * the front of previous prog
         */
        if (env->subprog_info[j].start != off + cnt)
                j--;

        if (j > i) {
                struct bpf_prog_aux *aux = env->prog->aux;
                int move;

                /* move fake 'exit' subprog as well */
                move = env->subprog_cnt + 1 - j;

                memmove(env->subprog_info + i,
                        env->subprog_info + j,
                        sizeof(*env->subprog_info) * move);
                env->subprog_cnt -= j - i;

                /* remove func_info */
                if (aux->func_info) {
                        move = aux->func_info_cnt - j;

                        memmove(aux->func_info + i,
                                aux->func_info + j,
                                sizeof(*aux->func_info) * move);
                        aux->func_info_cnt -= j - i;
                        /* func_info->insn_off is set after all code rewrites,
                         * in adjust_btf_func() - no need to adjust
                         */
                }
        } else {
                /* convert i from "first prog to remove" to "first to adjust" */
                if (env->subprog_info[i].start == off)
                        i++;
        }

        /* update fake 'exit' subprog as well */
        for (; i <= env->subprog_cnt; i++)
                env->subprog_info[i].start -= cnt;

        return 0;
}

static int bpf_adj_linfo_after_remove(struct bpf_verifier_env *env, u32 off,
                                      u32 cnt)
{
        struct bpf_prog *prog = env->prog;
        u32 i, l_off, l_cnt, nr_linfo;
        struct bpf_line_info *linfo;

        nr_linfo = prog->aux->nr_linfo;
        if (!nr_linfo)
                return 0;

        linfo = prog->aux->linfo;

        /* find first line info to remove, count lines to be removed */
        for (i = 0; i < nr_linfo; i++)
                if (linfo[i].insn_off >= off)
                        break;

        l_off = i;
        l_cnt = 0;
        for (; i < nr_linfo; i++)
                if (linfo[i].insn_off < off + cnt)
                        l_cnt++;
                else
                        break;

        /* First live insn doesn't match first live linfo, it needs to "inherit"
         * last removed linfo.  prog is already modified, so prog->len == off
         * means no live instructions after (tail of the program was removed).
         */
        if (prog->len != off && l_cnt &&
            (i == nr_linfo || linfo[i].insn_off != off + cnt)) {
                l_cnt--;
                linfo[--i].insn_off = off + cnt;
        }

        /* remove the line info which refer to the removed instructions */
        if (l_cnt) {
                memmove(linfo + l_off, linfo + i,
                        sizeof(*linfo) * (nr_linfo - i));

                prog->aux->nr_linfo -= l_cnt;
                nr_linfo = prog->aux->nr_linfo;
        }

        /* pull all linfo[i].insn_off >= off + cnt in by cnt */
        for (i = l_off; i < nr_linfo; i++)
                linfo[i].insn_off -= cnt;

        /* fix up all subprogs (incl. 'exit') which start >= off */
        for (i = 0; i <= env->subprog_cnt; i++)
                if (env->subprog_info[i].linfo_idx > l_off) {
                        /* program may have started in the removed region but
                         * may not be fully removed
                         */
                        if (env->subprog_info[i].linfo_idx >= l_off + l_cnt)
                                env->subprog_info[i].linfo_idx -= l_cnt;
                        else
                                env->subprog_info[i].linfo_idx = l_off;
                }

        return 0;
}

/*
 * Clean up dynamically allocated fields of aux data for instructions [start, ...]
 */
void bpf_clear_insn_aux_data(struct bpf_verifier_env *env, int start, int len)
{
        struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
        struct bpf_insn *insns = env->prog->insnsi;
        int end = start + len;
        int i;

        for (i = start; i < end; i++) {
                if (aux_data[i].jt) {
                        kvfree(aux_data[i].jt);
                        aux_data[i].jt = NULL;
                }

                if (bpf_is_ldimm64(&insns[i]))
                        i++;
        }
}

static int verifier_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt)
{
        struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
        unsigned int orig_prog_len = env->prog->len;
        int err;

        if (bpf_prog_is_offloaded(env->prog->aux))
                bpf_prog_offload_remove_insns(env, off, cnt);

        /* Should be called before bpf_remove_insns, as it uses prog->insnsi */
        bpf_clear_insn_aux_data(env, off, cnt);

        err = bpf_remove_insns(env->prog, off, cnt);
        if (err)
                return err;

        err = adjust_subprog_starts_after_remove(env, off, cnt);
        if (err)
                return err;

        err = bpf_adj_linfo_after_remove(env, off, cnt);
        if (err)
                return err;

        adjust_insn_arrays_after_remove(env, off, cnt);

        memmove(aux_data + off, aux_data + off + cnt,
                sizeof(*aux_data) * (orig_prog_len - off - cnt));

        return 0;
}

static const struct bpf_insn NOP = BPF_JMP_IMM(BPF_JA, 0, 0, 0);
static const struct bpf_insn MAY_GOTO_0 = BPF_RAW_INSN(BPF_JMP | BPF_JCOND, 0, 0, 0, 0);

bool bpf_insn_is_cond_jump(u8 code)
{
        u8 op;

        op = BPF_OP(code);
        if (BPF_CLASS(code) == BPF_JMP32)
                return op != BPF_JA;

        if (BPF_CLASS(code) != BPF_JMP)
                return false;

        return op != BPF_JA && op != BPF_EXIT && op != BPF_CALL;
}

void bpf_opt_hard_wire_dead_code_branches(struct bpf_verifier_env *env)
{
        struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
        struct bpf_insn ja = BPF_JMP_IMM(BPF_JA, 0, 0, 0);
        struct bpf_insn *insn = env->prog->insnsi;
        const int insn_cnt = env->prog->len;
        int i;

        for (i = 0; i < insn_cnt; i++, insn++) {
                if (!bpf_insn_is_cond_jump(insn->code))
                        continue;

                if (!aux_data[i + 1].seen)
                        ja.off = insn->off;
                else if (!aux_data[i + 1 + insn->off].seen)
                        ja.off = 0;
                else
                        continue;

                if (bpf_prog_is_offloaded(env->prog->aux))
                        bpf_prog_offload_replace_insn(env, i, &ja);

                memcpy(insn, &ja, sizeof(ja));
        }
}

int bpf_opt_remove_dead_code(struct bpf_verifier_env *env)
{
        struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
        int insn_cnt = env->prog->len;
        int i, err;

        for (i = 0; i < insn_cnt; i++) {
                int j;

                j = 0;
                while (i + j < insn_cnt && !aux_data[i + j].seen)
                        j++;
                if (!j)
                        continue;

                err = verifier_remove_insns(env, i, j);
                if (err)
                        return err;
                insn_cnt = env->prog->len;
        }

        return 0;
}

int bpf_opt_remove_nops(struct bpf_verifier_env *env)
{
        struct bpf_insn *insn = env->prog->insnsi;
        int insn_cnt = env->prog->len;
        bool is_may_goto_0, is_ja;
        int i, err;

        for (i = 0; i < insn_cnt; i++) {
                is_may_goto_0 = !memcmp(&insn[i], &MAY_GOTO_0, sizeof(MAY_GOTO_0));
                is_ja = !memcmp(&insn[i], &NOP, sizeof(NOP));

                if (!is_may_goto_0 && !is_ja)
                        continue;

                err = verifier_remove_insns(env, i, 1);
                if (err)
                        return err;
                insn_cnt--;
                /* Go back one insn to catch may_goto +1; may_goto +0 sequence */
                i -= (is_may_goto_0 && i > 0) ? 2 : 1;
        }

        return 0;
}

int bpf_opt_subreg_zext_lo32_rnd_hi32(struct bpf_verifier_env *env,
                                         const union bpf_attr *attr)
{
        struct bpf_insn *patch;
        /* use env->insn_buf as two independent buffers */
        struct bpf_insn *zext_patch = env->insn_buf;
        struct bpf_insn *rnd_hi32_patch = &env->insn_buf[2];
        struct bpf_insn_aux_data *aux = env->insn_aux_data;
        int i, patch_len, delta = 0, len = env->prog->len;
        struct bpf_insn *insns = env->prog->insnsi;
        struct bpf_prog *new_prog;
        bool rnd_hi32;

        rnd_hi32 = attr->prog_flags & BPF_F_TEST_RND_HI32;
        zext_patch[1] = BPF_ZEXT_REG(0);
        rnd_hi32_patch[1] = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, 0);
        rnd_hi32_patch[2] = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32);
        rnd_hi32_patch[3] = BPF_ALU64_REG(BPF_OR, 0, BPF_REG_AX);
        for (i = 0; i < len; i++) {
                int adj_idx = i + delta;
                struct bpf_insn insn;
                int load_reg;

                insn = insns[adj_idx];
                load_reg = insn_def_regno(&insn);
                if (!aux[adj_idx].zext_dst) {
                        u8 code, class;
                        u32 imm_rnd;

                        if (!rnd_hi32)
                                continue;

                        code = insn.code;
                        class = BPF_CLASS(code);
                        if (load_reg == -1)
                                continue;

                        /* NOTE: arg "reg" (the fourth one) is only used for
                         *       BPF_STX + SRC_OP, so it is safe to pass NULL
                         *       here.
                         */
                        if (bpf_is_reg64(&insn, load_reg, NULL, DST_OP)) {
                                if (class == BPF_LD &&
                                    BPF_MODE(code) == BPF_IMM)
                                        i++;
                                continue;
                        }

                        /* ctx load could be transformed into wider load. */
                        if (class == BPF_LDX &&
                            aux[adj_idx].ptr_type == PTR_TO_CTX)
                                continue;

                        imm_rnd = get_random_u32();
                        rnd_hi32_patch[0] = insn;
                        rnd_hi32_patch[1].imm = imm_rnd;
                        rnd_hi32_patch[3].dst_reg = load_reg;
                        patch = rnd_hi32_patch;
                        patch_len = 4;
                        goto apply_patch_buffer;
                }

                /* Add in an zero-extend instruction if a) the JIT has requested
                 * it or b) it's a CMPXCHG.
                 *
                 * The latter is because: BPF_CMPXCHG always loads a value into
                 * R0, therefore always zero-extends. However some archs'
                 * equivalent instruction only does this load when the
                 * comparison is successful. This detail of CMPXCHG is
                 * orthogonal to the general zero-extension behaviour of the
                 * CPU, so it's treated independently of bpf_jit_needs_zext.
                 */
                if (!bpf_jit_needs_zext() && !is_cmpxchg_insn(&insn))
                        continue;

                /* Zero-extension is done by the caller. */
                if (bpf_pseudo_kfunc_call(&insn))
                        continue;

                if (verifier_bug_if(load_reg == -1, env,
                                    "zext_dst is set, but no reg is defined"))
                        return -EFAULT;

                zext_patch[0] = insn;
                zext_patch[1].dst_reg = load_reg;
                zext_patch[1].src_reg = load_reg;
                patch = zext_patch;
                patch_len = 2;
apply_patch_buffer:
                new_prog = bpf_patch_insn_data(env, adj_idx, patch, patch_len);
                if (!new_prog)
                        return -ENOMEM;
                env->prog = new_prog;
                insns = new_prog->insnsi;
                aux = env->insn_aux_data;
                delta += patch_len - 1;
        }

        return 0;
}

/* convert load instructions that access fields of a context type into a
 * sequence of instructions that access fields of the underlying structure:
 *     struct __sk_buff    -> struct sk_buff
 *     struct bpf_sock_ops -> struct sock
 */
int bpf_convert_ctx_accesses(struct bpf_verifier_env *env)
{
        struct bpf_subprog_info *subprogs = env->subprog_info;
        const struct bpf_verifier_ops *ops = env->ops;
        int i, cnt, size, ctx_field_size, ret, delta = 0, epilogue_cnt = 0;
        const int insn_cnt = env->prog->len;
        struct bpf_insn *epilogue_buf = env->epilogue_buf;
        struct bpf_insn *insn_buf = env->insn_buf;
        struct bpf_insn *insn;
        u32 target_size, size_default, off;
        struct bpf_prog *new_prog;
        enum bpf_access_type type;
        bool is_narrower_load;
        int epilogue_idx = 0;

        if (ops->gen_epilogue) {
                epilogue_cnt = ops->gen_epilogue(epilogue_buf, env->prog,
                                                 -(subprogs[0].stack_depth + 8));
                if (epilogue_cnt >= INSN_BUF_SIZE) {
                        verifier_bug(env, "epilogue is too long");
                        return -EFAULT;
                } else if (epilogue_cnt) {
                        /* Save the ARG_PTR_TO_CTX for the epilogue to use */
                        cnt = 0;
                        subprogs[0].stack_depth += 8;
                        insn_buf[cnt++] = BPF_STX_MEM(BPF_DW, BPF_REG_FP, BPF_REG_1,
                                                      -subprogs[0].stack_depth);
                        insn_buf[cnt++] = env->prog->insnsi[0];
                        new_prog = bpf_patch_insn_data(env, 0, insn_buf, cnt);
                        if (!new_prog)
                                return -ENOMEM;
                        env->prog = new_prog;
                        delta += cnt - 1;

                        ret = add_kfunc_in_insns(env, epilogue_buf, epilogue_cnt - 1);
                        if (ret < 0)
                                return ret;
                }
        }

        if (ops->gen_prologue || env->seen_direct_write) {
                if (!ops->gen_prologue) {
                        verifier_bug(env, "gen_prologue is null");
                        return -EFAULT;
                }
                cnt = ops->gen_prologue(insn_buf, env->seen_direct_write,
                                        env->prog);
                if (cnt >= INSN_BUF_SIZE) {
                        verifier_bug(env, "prologue is too long");
                        return -EFAULT;
                } else if (cnt) {
                        new_prog = bpf_patch_insn_data(env, 0, insn_buf, cnt);
                        if (!new_prog)
                                return -ENOMEM;

                        env->prog = new_prog;
                        delta += cnt - 1;

                        ret = add_kfunc_in_insns(env, insn_buf, cnt - 1);
                        if (ret < 0)
                                return ret;
                }
        }

        if (delta)
                WARN_ON(adjust_jmp_off(env->prog, 0, delta));

        if (bpf_prog_is_offloaded(env->prog->aux))
                return 0;

        insn = env->prog->insnsi + delta;

        for (i = 0; i < insn_cnt; i++, insn++) {
                bpf_convert_ctx_access_t convert_ctx_access;
                u8 mode;

                if (env->insn_aux_data[i + delta].nospec) {
                        WARN_ON_ONCE(env->insn_aux_data[i + delta].alu_state);
                        struct bpf_insn *patch = insn_buf;

                        *patch++ = BPF_ST_NOSPEC();
                        *patch++ = *insn;
                        cnt = patch - insn_buf;
                        new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
                        if (!new_prog)
                                return -ENOMEM;

                        delta    += cnt - 1;
                        env->prog = new_prog;
                        insn      = new_prog->insnsi + i + delta;
                        /* This can not be easily merged with the
                         * nospec_result-case, because an insn may require a
                         * nospec before and after itself. Therefore also do not
                         * 'continue' here but potentially apply further
                         * patching to insn. *insn should equal patch[1] now.
                         */
                }

                if (insn->code == (BPF_LDX | BPF_MEM | BPF_B) ||
                    insn->code == (BPF_LDX | BPF_MEM | BPF_H) ||
                    insn->code == (BPF_LDX | BPF_MEM | BPF_W) ||
                    insn->code == (BPF_LDX | BPF_MEM | BPF_DW) ||
                    insn->code == (BPF_LDX | BPF_MEMSX | BPF_B) ||
                    insn->code == (BPF_LDX | BPF_MEMSX | BPF_H) ||
                    insn->code == (BPF_LDX | BPF_MEMSX | BPF_W)) {
                        type = BPF_READ;
                } else if (insn->code == (BPF_STX | BPF_MEM | BPF_B) ||
                           insn->code == (BPF_STX | BPF_MEM | BPF_H) ||
                           insn->code == (BPF_STX | BPF_MEM | BPF_W) ||
                           insn->code == (BPF_STX | BPF_MEM | BPF_DW) ||
                           insn->code == (BPF_ST | BPF_MEM | BPF_B) ||
                           insn->code == (BPF_ST | BPF_MEM | BPF_H) ||
                           insn->code == (BPF_ST | BPF_MEM | BPF_W) ||
                           insn->code == (BPF_ST | BPF_MEM | BPF_DW)) {
                        type = BPF_WRITE;
                } else if ((insn->code == (BPF_STX | BPF_ATOMIC | BPF_B) ||
                            insn->code == (BPF_STX | BPF_ATOMIC | BPF_H) ||
                            insn->code == (BPF_STX | BPF_ATOMIC | BPF_W) ||
                            insn->code == (BPF_STX | BPF_ATOMIC | BPF_DW)) &&
                           env->insn_aux_data[i + delta].ptr_type == PTR_TO_ARENA) {
                        insn->code = BPF_STX | BPF_PROBE_ATOMIC | BPF_SIZE(insn->code);
                        env->prog->aux->num_exentries++;
                        continue;
                } else if (insn->code == (BPF_JMP | BPF_EXIT) &&
                           epilogue_cnt &&
                           i + delta < subprogs[1].start) {
                        /* Generate epilogue for the main prog */
                        if (epilogue_idx) {
                                /* jump back to the earlier generated epilogue */
                                insn_buf[0] = BPF_JMP32_A(epilogue_idx - i - delta - 1);
                                cnt = 1;
                        } else {
                                memcpy(insn_buf, epilogue_buf,
                                       epilogue_cnt * sizeof(*epilogue_buf));
                                cnt = epilogue_cnt;
                                /* epilogue_idx cannot be 0. It must have at
                                 * least one ctx ptr saving insn before the
                                 * epilogue.
                                 */
                                epilogue_idx = i + delta;
                        }
                        goto patch_insn_buf;
                } else {
                        continue;
                }

                if (type == BPF_WRITE &&
                    env->insn_aux_data[i + delta].nospec_result) {
                        /* nospec_result is only used to mitigate Spectre v4 and
                         * to limit verification-time for Spectre v1.
                         */
                        struct bpf_insn *patch = insn_buf;

                        *patch++ = *insn;
                        *patch++ = BPF_ST_NOSPEC();
                        cnt = patch - insn_buf;
                        new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
                        if (!new_prog)
                                return -ENOMEM;

                        delta    += cnt - 1;
                        env->prog = new_prog;
                        insn      = new_prog->insnsi + i + delta;
                        continue;
                }

                switch ((int)env->insn_aux_data[i + delta].ptr_type) {
                case PTR_TO_CTX:
                        if (!ops->convert_ctx_access)
                                continue;
                        convert_ctx_access = ops->convert_ctx_access;
                        break;
                case PTR_TO_SOCKET:
                case PTR_TO_SOCK_COMMON:
                        convert_ctx_access = bpf_sock_convert_ctx_access;
                        break;
                case PTR_TO_TCP_SOCK:
                        convert_ctx_access = bpf_tcp_sock_convert_ctx_access;
                        break;
                case PTR_TO_XDP_SOCK:
                        convert_ctx_access = bpf_xdp_sock_convert_ctx_access;
                        break;
                case PTR_TO_BTF_ID:
                case PTR_TO_BTF_ID | PTR_UNTRUSTED:
                /* PTR_TO_BTF_ID | MEM_ALLOC always has a valid lifetime, unlike
                 * PTR_TO_BTF_ID, and an active ref_obj_id, but the same cannot
                 * be said once it is marked PTR_UNTRUSTED, hence we must handle
                 * any faults for loads into such types. BPF_WRITE is disallowed
                 * for this case.
                 */
                case PTR_TO_BTF_ID | MEM_ALLOC | PTR_UNTRUSTED:
                case PTR_TO_MEM | MEM_RDONLY | PTR_UNTRUSTED:
                        if (type == BPF_READ) {
                                if (BPF_MODE(insn->code) == BPF_MEM)
                                        insn->code = BPF_LDX | BPF_PROBE_MEM |
                                                     BPF_SIZE((insn)->code);
                                else
                                        insn->code = BPF_LDX | BPF_PROBE_MEMSX |
                                                     BPF_SIZE((insn)->code);
                                env->prog->aux->num_exentries++;
                        }
                        continue;
                case PTR_TO_ARENA:
                        if (BPF_MODE(insn->code) == BPF_MEMSX) {
                                if (!bpf_jit_supports_insn(insn, true)) {
                                        verbose(env, "sign extending loads from arena are not supported yet\n");
                                        return -EOPNOTSUPP;
                                }
                                insn->code = BPF_CLASS(insn->code) | BPF_PROBE_MEM32SX | BPF_SIZE(insn->code);
                        } else {
                                insn->code = BPF_CLASS(insn->code) | BPF_PROBE_MEM32 | BPF_SIZE(insn->code);
                        }
                        env->prog->aux->num_exentries++;
                        continue;
                default:
                        continue;
                }

                ctx_field_size = env->insn_aux_data[i + delta].ctx_field_size;
                size = BPF_LDST_BYTES(insn);
                mode = BPF_MODE(insn->code);

                /* If the read access is a narrower load of the field,
                 * convert to a 4/8-byte load, to minimum program type specific
                 * convert_ctx_access changes. If conversion is successful,
                 * we will apply proper mask to the result.
                 */
                is_narrower_load = size < ctx_field_size;
                size_default = bpf_ctx_off_adjust_machine(ctx_field_size);
                off = insn->off;
                if (is_narrower_load) {
                        u8 size_code;

                        if (type == BPF_WRITE) {
                                verifier_bug(env, "narrow ctx access misconfigured");
                                return -EFAULT;
                        }

                        size_code = BPF_H;
                        if (ctx_field_size == 4)
                                size_code = BPF_W;
                        else if (ctx_field_size == 8)
                                size_code = BPF_DW;

                        insn->off = off & ~(size_default - 1);
                        insn->code = BPF_LDX | BPF_MEM | size_code;
                }

                target_size = 0;
                cnt = convert_ctx_access(type, insn, insn_buf, env->prog,
                                         &target_size);
                if (cnt == 0 || cnt >= INSN_BUF_SIZE ||
                    (ctx_field_size && !target_size)) {
                        verifier_bug(env, "error during ctx access conversion (%d)", cnt);
                        return -EFAULT;
                }

                if (is_narrower_load && size < target_size) {
                        u8 shift = bpf_ctx_narrow_access_offset(
                                off, size, size_default) * 8;
                        if (shift && cnt + 1 >= INSN_BUF_SIZE) {
                                verifier_bug(env, "narrow ctx load misconfigured");
                                return -EFAULT;
                        }
                        if (ctx_field_size <= 4) {
                                if (shift)
                                        insn_buf[cnt++] = BPF_ALU32_IMM(BPF_RSH,
                                                                        insn->dst_reg,
                                                                        shift);
                                insn_buf[cnt++] = BPF_ALU32_IMM(BPF_AND, insn->dst_reg,
                                                                (1 << size * 8) - 1);
                        } else {
                                if (shift)
                                        insn_buf[cnt++] = BPF_ALU64_IMM(BPF_RSH,
                                                                        insn->dst_reg,
                                                                        shift);
                                insn_buf[cnt++] = BPF_ALU32_IMM(BPF_AND, insn->dst_reg,
                                                                (1ULL << size * 8) - 1);
                        }
                }
                if (mode == BPF_MEMSX)
                        insn_buf[cnt++] = BPF_RAW_INSN(BPF_ALU64 | BPF_MOV | BPF_X,
                                                       insn->dst_reg, insn->dst_reg,
                                                       size * 8, 0);

patch_insn_buf:
                new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
                if (!new_prog)
                        return -ENOMEM;

                delta += cnt - 1;

                /* keep walking new program and skip insns we just inserted */
                env->prog = new_prog;
                insn      = new_prog->insnsi + i + delta;
        }

        return 0;
}

int bpf_jit_subprogs(struct bpf_verifier_env *env)
{
        struct bpf_prog *prog = env->prog, **func, *tmp;
        int i, j, subprog_start, subprog_end = 0, len, subprog;
        struct bpf_map *map_ptr;
        struct bpf_insn *insn;
        void *old_bpf_func;
        int err, num_exentries;
        int old_len, subprog_start_adjustment = 0;

        if (env->subprog_cnt <= 1)
                return 0;

        for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) {
                if (!bpf_pseudo_func(insn) && !bpf_pseudo_call(insn))
                        continue;

                /* Upon error here we cannot fall back to interpreter but
                 * need a hard reject of the program. Thus -EFAULT is
                 * propagated in any case.
                 */
                subprog = bpf_find_subprog(env, i + insn->imm + 1);
                if (verifier_bug_if(subprog < 0, env, "No program to jit at insn %d",
                                    i + insn->imm + 1))
                        return -EFAULT;
                /* temporarily remember subprog id inside insn instead of
                 * aux_data, since next loop will split up all insns into funcs
                 */
                insn->off = subprog;
                /* remember original imm in case JIT fails and fallback
                 * to interpreter will be needed
                 */
                env->insn_aux_data[i].call_imm = insn->imm;
                /* point imm to __bpf_call_base+1 from JITs point of view */
                insn->imm = 1;
                if (bpf_pseudo_func(insn)) {
#if defined(MODULES_VADDR)
                        u64 addr = MODULES_VADDR;
#else
                        u64 addr = VMALLOC_START;
#endif
                        /* jit (e.g. x86_64) may emit fewer instructions
                         * if it learns a u32 imm is the same as a u64 imm.
                         * Set close enough to possible prog address.
                         */
                        insn[0].imm = (u32)addr;
                        insn[1].imm = addr >> 32;
                }
        }

        err = bpf_prog_alloc_jited_linfo(prog);
        if (err)
                goto out_undo_insn;

        err = -ENOMEM;
        func = kzalloc_objs(prog, env->subprog_cnt);
        if (!func)
                goto out_undo_insn;

        for (i = 0; i < env->subprog_cnt; i++) {
                subprog_start = subprog_end;
                subprog_end = env->subprog_info[i + 1].start;

                len = subprog_end - subprog_start;
                /* bpf_prog_run() doesn't call subprogs directly,
                 * hence main prog stats include the runtime of subprogs.
                 * subprogs don't have IDs and not reachable via prog_get_next_id
                 * func[i]->stats will never be accessed and stays NULL
                 */
                func[i] = bpf_prog_alloc_no_stats(bpf_prog_size(len), GFP_USER);
                if (!func[i])
                        goto out_free;
                memcpy(func[i]->insnsi, &prog->insnsi[subprog_start],
                       len * sizeof(struct bpf_insn));
                func[i]->type = prog->type;
                func[i]->len = len;
                if (bpf_prog_calc_tag(func[i]))
                        goto out_free;
                func[i]->is_func = 1;
                func[i]->sleepable = prog->sleepable;
                func[i]->aux->func_idx = i;
                /* Below members will be freed only at prog->aux */
                func[i]->aux->btf = prog->aux->btf;
                func[i]->aux->subprog_start = subprog_start + subprog_start_adjustment;
                func[i]->aux->func_info = prog->aux->func_info;
                func[i]->aux->func_info_cnt = prog->aux->func_info_cnt;
                func[i]->aux->poke_tab = prog->aux->poke_tab;
                func[i]->aux->size_poke_tab = prog->aux->size_poke_tab;
                func[i]->aux->main_prog_aux = prog->aux;

                for (j = 0; j < prog->aux->size_poke_tab; j++) {
                        struct bpf_jit_poke_descriptor *poke;

                        poke = &prog->aux->poke_tab[j];
                        if (poke->insn_idx < subprog_end &&
                            poke->insn_idx >= subprog_start)
                                poke->aux = func[i]->aux;
                }

                func[i]->aux->name[0] = 'F';
                func[i]->aux->stack_depth = env->subprog_info[i].stack_depth;
                if (env->subprog_info[i].priv_stack_mode == PRIV_STACK_ADAPTIVE)
                        func[i]->aux->jits_use_priv_stack = true;

                func[i]->jit_requested = 1;
                func[i]->blinding_requested = prog->blinding_requested;
                func[i]->aux->kfunc_tab = prog->aux->kfunc_tab;
                func[i]->aux->kfunc_btf_tab = prog->aux->kfunc_btf_tab;
                func[i]->aux->linfo = prog->aux->linfo;
                func[i]->aux->nr_linfo = prog->aux->nr_linfo;
                func[i]->aux->jited_linfo = prog->aux->jited_linfo;
                func[i]->aux->linfo_idx = env->subprog_info[i].linfo_idx;
                func[i]->aux->arena = prog->aux->arena;
                func[i]->aux->used_maps = env->used_maps;
                func[i]->aux->used_map_cnt = env->used_map_cnt;
                num_exentries = 0;
                insn = func[i]->insnsi;
                for (j = 0; j < func[i]->len; j++, insn++) {
                        if (BPF_CLASS(insn->code) == BPF_LDX &&
                            (BPF_MODE(insn->code) == BPF_PROBE_MEM ||
                             BPF_MODE(insn->code) == BPF_PROBE_MEM32 ||
                             BPF_MODE(insn->code) == BPF_PROBE_MEM32SX ||
                             BPF_MODE(insn->code) == BPF_PROBE_MEMSX))
                                num_exentries++;
                        if ((BPF_CLASS(insn->code) == BPF_STX ||
                             BPF_CLASS(insn->code) == BPF_ST) &&
                             BPF_MODE(insn->code) == BPF_PROBE_MEM32)
                                num_exentries++;
                        if (BPF_CLASS(insn->code) == BPF_STX &&
                             BPF_MODE(insn->code) == BPF_PROBE_ATOMIC)
                                num_exentries++;
                }
                func[i]->aux->num_exentries = num_exentries;
                func[i]->aux->tail_call_reachable = env->subprog_info[i].tail_call_reachable;
                func[i]->aux->exception_cb = env->subprog_info[i].is_exception_cb;
                func[i]->aux->changes_pkt_data = env->subprog_info[i].changes_pkt_data;
                func[i]->aux->might_sleep = env->subprog_info[i].might_sleep;
                if (!i)
                        func[i]->aux->exception_boundary = env->seen_exception;

                /*
                 * To properly pass the absolute subprog start to jit
                 * all instruction adjustments should be accumulated
                 */
                old_len = func[i]->len;
                func[i] = bpf_int_jit_compile(func[i]);
                subprog_start_adjustment += func[i]->len - old_len;

                if (!func[i]->jited) {
                        err = -ENOTSUPP;
                        goto out_free;
                }
                cond_resched();
        }

        /* at this point all bpf functions were successfully JITed
         * now populate all bpf_calls with correct addresses and
         * run last pass of JIT
         */
        for (i = 0; i < env->subprog_cnt; i++) {
                insn = func[i]->insnsi;
                for (j = 0; j < func[i]->len; j++, insn++) {
                        if (bpf_pseudo_func(insn)) {
                                subprog = insn->off;
                                insn[0].imm = (u32)(long)func[subprog]->bpf_func;
                                insn[1].imm = ((u64)(long)func[subprog]->bpf_func) >> 32;
                                continue;
                        }
                        if (!bpf_pseudo_call(insn))
                                continue;
                        subprog = insn->off;
                        insn->imm = BPF_CALL_IMM(func[subprog]->bpf_func);
                }

                /* we use the aux data to keep a list of the start addresses
                 * of the JITed images for each function in the program
                 *
                 * for some architectures, such as powerpc64, the imm field
                 * might not be large enough to hold the offset of the start
                 * address of the callee's JITed image from __bpf_call_base
                 *
                 * in such cases, we can lookup the start address of a callee
                 * by using its subprog id, available from the off field of
                 * the call instruction, as an index for this list
                 */
                func[i]->aux->func = func;
                func[i]->aux->func_cnt = env->subprog_cnt - env->hidden_subprog_cnt;
                func[i]->aux->real_func_cnt = env->subprog_cnt;
        }
        for (i = 0; i < env->subprog_cnt; i++) {
                old_bpf_func = func[i]->bpf_func;
                tmp = bpf_int_jit_compile(func[i]);
                if (tmp != func[i] || func[i]->bpf_func != old_bpf_func) {
                        verbose(env, "JIT doesn't support bpf-to-bpf calls\n");
                        err = -ENOTSUPP;
                        goto out_free;
                }
                cond_resched();
        }

        /*
         * Cleanup func[i]->aux fields which aren't required
         * or can become invalid in future
         */
        for (i = 0; i < env->subprog_cnt; i++) {
                func[i]->aux->used_maps = NULL;
                func[i]->aux->used_map_cnt = 0;
        }

        /* finally lock prog and jit images for all functions and
         * populate kallsysm. Begin at the first subprogram, since
         * bpf_prog_load will add the kallsyms for the main program.
         */
        for (i = 1; i < env->subprog_cnt; i++) {
                err = bpf_prog_lock_ro(func[i]);
                if (err)
                        goto out_free;
        }

        for (i = 1; i < env->subprog_cnt; i++)
                bpf_prog_kallsyms_add(func[i]);

        /* Last step: make now unused interpreter insns from main
         * prog consistent for later dump requests, so they can
         * later look the same as if they were interpreted only.
         */
        for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) {
                if (bpf_pseudo_func(insn)) {
                        insn[0].imm = env->insn_aux_data[i].call_imm;
                        insn[1].imm = insn->off;
                        insn->off = 0;
                        continue;
                }
                if (!bpf_pseudo_call(insn))
                        continue;
                insn->off = env->insn_aux_data[i].call_imm;
                subprog = bpf_find_subprog(env, i + insn->off + 1);
                insn->imm = subprog;
        }

        prog->jited = 1;
        prog->bpf_func = func[0]->bpf_func;
        prog->jited_len = func[0]->jited_len;
        prog->aux->extable = func[0]->aux->extable;
        prog->aux->num_exentries = func[0]->aux->num_exentries;
        prog->aux->func = func;
        prog->aux->func_cnt = env->subprog_cnt - env->hidden_subprog_cnt;
        prog->aux->real_func_cnt = env->subprog_cnt;
        prog->aux->bpf_exception_cb = (void *)func[env->exception_callback_subprog]->bpf_func;
        prog->aux->exception_boundary = func[0]->aux->exception_boundary;
        bpf_prog_jit_attempt_done(prog);
        return 0;
out_free:
        /* We failed JIT'ing, so at this point we need to unregister poke
         * descriptors from subprogs, so that kernel is not attempting to
         * patch it anymore as we're freeing the subprog JIT memory.
         */
        for (i = 0; i < prog->aux->size_poke_tab; i++) {
                map_ptr = prog->aux->poke_tab[i].tail_call.map;
                map_ptr->ops->map_poke_untrack(map_ptr, prog->aux);
        }
        /* At this point we're guaranteed that poke descriptors are not
         * live anymore. We can just unlink its descriptor table as it's
         * released with the main prog.
         */
        for (i = 0; i < env->subprog_cnt; i++) {
                if (!func[i])
                        continue;
                func[i]->aux->poke_tab = NULL;
                bpf_jit_free(func[i]);
        }
        kfree(func);
out_undo_insn:
        /* cleanup main prog to be interpreted */
        prog->jit_requested = 0;
        prog->blinding_requested = 0;
        for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) {
                if (!bpf_pseudo_call(insn))
                        continue;
                insn->off = 0;
                insn->imm = env->insn_aux_data[i].call_imm;
        }
        bpf_prog_jit_attempt_done(prog);
        return err;
}

int bpf_fixup_call_args(struct bpf_verifier_env *env)
{
#ifndef CONFIG_BPF_JIT_ALWAYS_ON
        struct bpf_prog *prog = env->prog;
        struct bpf_insn *insn = prog->insnsi;
        bool has_kfunc_call = bpf_prog_has_kfunc_call(prog);
        int i, depth;
#endif
        int err = 0;

        if (env->prog->jit_requested &&
            !bpf_prog_is_offloaded(env->prog->aux)) {
                err = bpf_jit_subprogs(env);
                if (err == 0)
                        return 0;
                if (err == -EFAULT)
                        return err;
        }
#ifndef CONFIG_BPF_JIT_ALWAYS_ON
        if (has_kfunc_call) {
                verbose(env, "calling kernel functions are not allowed in non-JITed programs\n");
                return -EINVAL;
        }
        if (env->subprog_cnt > 1 && env->prog->aux->tail_call_reachable) {
                /* When JIT fails the progs with bpf2bpf calls and tail_calls
                 * have to be rejected, since interpreter doesn't support them yet.
                 */
                verbose(env, "tail_calls are not allowed in non-JITed programs with bpf-to-bpf calls\n");
                return -EINVAL;
        }
        for (i = 0; i < prog->len; i++, insn++) {
                if (bpf_pseudo_func(insn)) {
                        /* When JIT fails the progs with callback calls
                         * have to be rejected, since interpreter doesn't support them yet.
                         */
                        verbose(env, "callbacks are not allowed in non-JITed programs\n");
                        return -EINVAL;
                }

                if (!bpf_pseudo_call(insn))
                        continue;
                depth = get_callee_stack_depth(env, insn, i);
                if (depth < 0)
                        return depth;
                bpf_patch_call_args(insn, depth);
        }
        err = 0;
#endif
        return err;
}


/* The function requires that first instruction in 'patch' is insnsi[prog->len - 1] */
static int add_hidden_subprog(struct bpf_verifier_env *env, struct bpf_insn *patch, int len)
{
        struct bpf_subprog_info *info = env->subprog_info;
        int cnt = env->subprog_cnt;
        struct bpf_prog *prog;

        /* We only reserve one slot for hidden subprogs in subprog_info. */
        if (env->hidden_subprog_cnt) {
                verifier_bug(env, "only one hidden subprog supported");
                return -EFAULT;
        }
        /* We're not patching any existing instruction, just appending the new
         * ones for the hidden subprog. Hence all of the adjustment operations
         * in bpf_patch_insn_data are no-ops.
         */
        prog = bpf_patch_insn_data(env, env->prog->len - 1, patch, len);
        if (!prog)
                return -ENOMEM;
        env->prog = prog;
        info[cnt + 1].start = info[cnt].start;
        info[cnt].start = prog->len - len + 1;
        env->subprog_cnt++;
        env->hidden_subprog_cnt++;
        return 0;
}

/* Do various post-verification rewrites in a single program pass.
 * These rewrites simplify JIT and interpreter implementations.
 */
int bpf_do_misc_fixups(struct bpf_verifier_env *env)
{
        struct bpf_prog *prog = env->prog;
        enum bpf_attach_type eatype = prog->expected_attach_type;
        enum bpf_prog_type prog_type = resolve_prog_type(prog);
        struct bpf_insn *insn = prog->insnsi;
        const struct bpf_func_proto *fn;
        const int insn_cnt = prog->len;
        const struct bpf_map_ops *ops;
        struct bpf_insn_aux_data *aux;
        struct bpf_insn *insn_buf = env->insn_buf;
        struct bpf_prog *new_prog;
        struct bpf_map *map_ptr;
        int i, ret, cnt, delta = 0, cur_subprog = 0;
        struct bpf_subprog_info *subprogs = env->subprog_info;
        u16 stack_depth = subprogs[cur_subprog].stack_depth;
        u16 stack_depth_extra = 0;

        if (env->seen_exception && !env->exception_callback_subprog) {
                struct bpf_insn *patch = insn_buf;

                *patch++ = env->prog->insnsi[insn_cnt - 1];
                *patch++ = BPF_MOV64_REG(BPF_REG_0, BPF_REG_1);
                *patch++ = BPF_EXIT_INSN();
                ret = add_hidden_subprog(env, insn_buf, patch - insn_buf);
                if (ret < 0)
                        return ret;
                prog = env->prog;
                insn = prog->insnsi;

                env->exception_callback_subprog = env->subprog_cnt - 1;
                /* Don't update insn_cnt, as add_hidden_subprog always appends insns */
                bpf_mark_subprog_exc_cb(env, env->exception_callback_subprog);
        }

        for (i = 0; i < insn_cnt;) {
                if (insn->code == (BPF_ALU64 | BPF_MOV | BPF_X) && insn->imm) {
                        if ((insn->off == BPF_ADDR_SPACE_CAST && insn->imm == 1) ||
                            (((struct bpf_map *)env->prog->aux->arena)->map_flags & BPF_F_NO_USER_CONV)) {
                                /* convert to 32-bit mov that clears upper 32-bit */
                                insn->code = BPF_ALU | BPF_MOV | BPF_X;
                                /* clear off and imm, so it's a normal 'wX = wY' from JIT pov */
                                insn->off = 0;
                                insn->imm = 0;
                        } /* cast from as(0) to as(1) should be handled by JIT */
                        goto next_insn;
                }

                if (env->insn_aux_data[i + delta].needs_zext)
                        /* Convert BPF_CLASS(insn->code) == BPF_ALU64 to 32-bit ALU */
                        insn->code = BPF_ALU | BPF_OP(insn->code) | BPF_SRC(insn->code);

                /* Make sdiv/smod divide-by-minus-one exceptions impossible. */
                if ((insn->code == (BPF_ALU64 | BPF_MOD | BPF_K) ||
                     insn->code == (BPF_ALU64 | BPF_DIV | BPF_K) ||
                     insn->code == (BPF_ALU | BPF_MOD | BPF_K) ||
                     insn->code == (BPF_ALU | BPF_DIV | BPF_K)) &&
                    insn->off == 1 && insn->imm == -1) {
                        bool is64 = BPF_CLASS(insn->code) == BPF_ALU64;
                        bool isdiv = BPF_OP(insn->code) == BPF_DIV;
                        struct bpf_insn *patch = insn_buf;

                        if (isdiv)
                                *patch++ = BPF_RAW_INSN((is64 ? BPF_ALU64 : BPF_ALU) |
                                                        BPF_NEG | BPF_K, insn->dst_reg,
                                                        0, 0, 0);
                        else
                                *patch++ = BPF_MOV32_IMM(insn->dst_reg, 0);

                        cnt = patch - insn_buf;

                        new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
                        if (!new_prog)
                                return -ENOMEM;

                        delta    += cnt - 1;
                        env->prog = prog = new_prog;
                        insn      = new_prog->insnsi + i + delta;
                        goto next_insn;
                }

                /* Make divide-by-zero and divide-by-minus-one exceptions impossible. */
                if (insn->code == (BPF_ALU64 | BPF_MOD | BPF_X) ||
                    insn->code == (BPF_ALU64 | BPF_DIV | BPF_X) ||
                    insn->code == (BPF_ALU | BPF_MOD | BPF_X) ||
                    insn->code == (BPF_ALU | BPF_DIV | BPF_X)) {
                        bool is64 = BPF_CLASS(insn->code) == BPF_ALU64;
                        bool isdiv = BPF_OP(insn->code) == BPF_DIV;
                        bool is_sdiv = isdiv && insn->off == 1;
                        bool is_smod = !isdiv && insn->off == 1;
                        struct bpf_insn *patch = insn_buf;

                        if (is_sdiv) {
                                /* [R,W]x sdiv 0 -> 0
                                 * LLONG_MIN sdiv -1 -> LLONG_MIN
                                 * INT_MIN sdiv -1 -> INT_MIN
                                 */
                                *patch++ = BPF_MOV64_REG(BPF_REG_AX, insn->src_reg);
                                *patch++ = BPF_RAW_INSN((is64 ? BPF_ALU64 : BPF_ALU) |
                                                        BPF_ADD | BPF_K, BPF_REG_AX,
                                                        0, 0, 1);
                                *patch++ = BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) |
                                                        BPF_JGT | BPF_K, BPF_REG_AX,
                                                        0, 4, 1);
                                *patch++ = BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) |
                                                        BPF_JEQ | BPF_K, BPF_REG_AX,
                                                        0, 1, 0);
                                *patch++ = BPF_RAW_INSN((is64 ? BPF_ALU64 : BPF_ALU) |
                                                        BPF_MOV | BPF_K, insn->dst_reg,
                                                        0, 0, 0);
                                /* BPF_NEG(LLONG_MIN) == -LLONG_MIN == LLONG_MIN */
                                *patch++ = BPF_RAW_INSN((is64 ? BPF_ALU64 : BPF_ALU) |
                                                        BPF_NEG | BPF_K, insn->dst_reg,
                                                        0, 0, 0);
                                *patch++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1);
                                *patch++ = *insn;
                                cnt = patch - insn_buf;
                        } else if (is_smod) {
                                /* [R,W]x mod 0 -> [R,W]x */
                                /* [R,W]x mod -1 -> 0 */
                                *patch++ = BPF_MOV64_REG(BPF_REG_AX, insn->src_reg);
                                *patch++ = BPF_RAW_INSN((is64 ? BPF_ALU64 : BPF_ALU) |
                                                        BPF_ADD | BPF_K, BPF_REG_AX,
                                                        0, 0, 1);
                                *patch++ = BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) |
                                                        BPF_JGT | BPF_K, BPF_REG_AX,
                                                        0, 3, 1);
                                *patch++ = BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) |
                                                        BPF_JEQ | BPF_K, BPF_REG_AX,
                                                        0, 3 + (is64 ? 0 : 1), 1);
                                *patch++ = BPF_MOV32_IMM(insn->dst_reg, 0);
                                *patch++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1);
                                *patch++ = *insn;

                                if (!is64) {
                                        *patch++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1);
                                        *patch++ = BPF_MOV32_REG(insn->dst_reg, insn->dst_reg);
                                }
                                cnt = patch - insn_buf;
                        } else if (isdiv) {
                                /* [R,W]x div 0 -> 0 */
                                *patch++ = BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) |
                                                        BPF_JNE | BPF_K, insn->src_reg,
                                                        0, 2, 0);
                                *patch++ = BPF_ALU32_REG(BPF_XOR, insn->dst_reg, insn->dst_reg);
                                *patch++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1);
                                *patch++ = *insn;
                                cnt = patch - insn_buf;
                        } else {
                                /* [R,W]x mod 0 -> [R,W]x */
                                *patch++ = BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) |
                                                        BPF_JEQ | BPF_K, insn->src_reg,
                                                        0, 1 + (is64 ? 0 : 1), 0);
                                *patch++ = *insn;

                                if (!is64) {
                                        *patch++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1);
                                        *patch++ = BPF_MOV32_REG(insn->dst_reg, insn->dst_reg);
                                }
                                cnt = patch - insn_buf;
                        }

                        new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
                        if (!new_prog)
                                return -ENOMEM;

                        delta    += cnt - 1;
                        env->prog = prog = new_prog;
                        insn      = new_prog->insnsi + i + delta;
                        goto next_insn;
                }

                /* Make it impossible to de-reference a userspace address */
                if (BPF_CLASS(insn->code) == BPF_LDX &&
                    (BPF_MODE(insn->code) == BPF_PROBE_MEM ||
                     BPF_MODE(insn->code) == BPF_PROBE_MEMSX)) {
                        struct bpf_insn *patch = insn_buf;
                        u64 uaddress_limit = bpf_arch_uaddress_limit();

                        if (!uaddress_limit)
                                goto next_insn;

                        *patch++ = BPF_MOV64_REG(BPF_REG_AX, insn->src_reg);
                        if (insn->off)
                                *patch++ = BPF_ALU64_IMM(BPF_ADD, BPF_REG_AX, insn->off);
                        *patch++ = BPF_ALU64_IMM(BPF_RSH, BPF_REG_AX, 32);
                        *patch++ = BPF_JMP_IMM(BPF_JLE, BPF_REG_AX, uaddress_limit >> 32, 2);
                        *patch++ = *insn;
                        *patch++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1);
                        *patch++ = BPF_MOV64_IMM(insn->dst_reg, 0);

                        cnt = patch - insn_buf;
                        new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
                        if (!new_prog)
                                return -ENOMEM;

                        delta    += cnt - 1;
                        env->prog = prog = new_prog;
                        insn      = new_prog->insnsi + i + delta;
                        goto next_insn;
                }

                /* Implement LD_ABS and LD_IND with a rewrite, if supported by the program type. */
                if (BPF_CLASS(insn->code) == BPF_LD &&
                    (BPF_MODE(insn->code) == BPF_ABS ||
                     BPF_MODE(insn->code) == BPF_IND)) {
                        cnt = env->ops->gen_ld_abs(insn, insn_buf);
                        if (cnt == 0 || cnt >= INSN_BUF_SIZE) {
                                verifier_bug(env, "%d insns generated for ld_abs", cnt);
                                return -EFAULT;
                        }

                        new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
                        if (!new_prog)
                                return -ENOMEM;

                        delta    += cnt - 1;
                        env->prog = prog = new_prog;
                        insn      = new_prog->insnsi + i + delta;
                        goto next_insn;
                }

                /* Rewrite pointer arithmetic to mitigate speculation attacks. */
                if (insn->code == (BPF_ALU64 | BPF_ADD | BPF_X) ||
                    insn->code == (BPF_ALU64 | BPF_SUB | BPF_X)) {
                        const u8 code_add = BPF_ALU64 | BPF_ADD | BPF_X;
                        const u8 code_sub = BPF_ALU64 | BPF_SUB | BPF_X;
                        struct bpf_insn *patch = insn_buf;
                        bool issrc, isneg, isimm;
                        u32 off_reg;

                        aux = &env->insn_aux_data[i + delta];
                        if (!aux->alu_state ||
                            aux->alu_state == BPF_ALU_NON_POINTER)
                                goto next_insn;

                        isneg = aux->alu_state & BPF_ALU_NEG_VALUE;
                        issrc = (aux->alu_state & BPF_ALU_SANITIZE) ==
                                BPF_ALU_SANITIZE_SRC;
                        isimm = aux->alu_state & BPF_ALU_IMMEDIATE;

                        off_reg = issrc ? insn->src_reg : insn->dst_reg;
                        if (isimm) {
                                *patch++ = BPF_MOV32_IMM(BPF_REG_AX, aux->alu_limit);
                        } else {
                                if (isneg)
                                        *patch++ = BPF_ALU64_IMM(BPF_MUL, off_reg, -1);
                                *patch++ = BPF_MOV32_IMM(BPF_REG_AX, aux->alu_limit);
                                *patch++ = BPF_ALU64_REG(BPF_SUB, BPF_REG_AX, off_reg);
                                *patch++ = BPF_ALU64_REG(BPF_OR, BPF_REG_AX, off_reg);
                                *patch++ = BPF_ALU64_IMM(BPF_NEG, BPF_REG_AX, 0);
                                *patch++ = BPF_ALU64_IMM(BPF_ARSH, BPF_REG_AX, 63);
                                *patch++ = BPF_ALU64_REG(BPF_AND, BPF_REG_AX, off_reg);
                        }
                        if (!issrc)
                                *patch++ = BPF_MOV64_REG(insn->dst_reg, insn->src_reg);
                        insn->src_reg = BPF_REG_AX;
                        if (isneg)
                                insn->code = insn->code == code_add ?
                                             code_sub : code_add;
                        *patch++ = *insn;
                        if (issrc && isneg && !isimm)
                                *patch++ = BPF_ALU64_IMM(BPF_MUL, off_reg, -1);
                        cnt = patch - insn_buf;

                        new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
                        if (!new_prog)
                                return -ENOMEM;

                        delta    += cnt - 1;
                        env->prog = prog = new_prog;
                        insn      = new_prog->insnsi + i + delta;
                        goto next_insn;
                }

                if (bpf_is_may_goto_insn(insn) && bpf_jit_supports_timed_may_goto()) {
                        int stack_off_cnt = -stack_depth - 16;

                        /*
                         * Two 8 byte slots, depth-16 stores the count, and
                         * depth-8 stores the start timestamp of the loop.
                         *
                         * The starting value of count is BPF_MAX_TIMED_LOOPS
                         * (0xffff).  Every iteration loads it and subs it by 1,
                         * until the value becomes 0 in AX (thus, 1 in stack),
                         * after which we call arch_bpf_timed_may_goto, which
                         * either sets AX to 0xffff to keep looping, or to 0
                         * upon timeout. AX is then stored into the stack. In
                         * the next iteration, we either see 0 and break out, or
                         * continue iterating until the next time value is 0
                         * after subtraction, rinse and repeat.
                         */
                        stack_depth_extra = 16;
                        insn_buf[0] = BPF_LDX_MEM(BPF_DW, BPF_REG_AX, BPF_REG_10, stack_off_cnt);
                        if (insn->off >= 0)
                                insn_buf[1] = BPF_JMP_IMM(BPF_JEQ, BPF_REG_AX, 0, insn->off + 5);
                        else
                                insn_buf[1] = BPF_JMP_IMM(BPF_JEQ, BPF_REG_AX, 0, insn->off - 1);
                        insn_buf[2] = BPF_ALU64_IMM(BPF_SUB, BPF_REG_AX, 1);
                        insn_buf[3] = BPF_JMP_IMM(BPF_JNE, BPF_REG_AX, 0, 2);
                        /*
                         * AX is used as an argument to pass in stack_off_cnt
                         * (to add to r10/fp), and also as the return value of
                         * the call to arch_bpf_timed_may_goto.
                         */
                        insn_buf[4] = BPF_MOV64_IMM(BPF_REG_AX, stack_off_cnt);
                        insn_buf[5] = BPF_EMIT_CALL(arch_bpf_timed_may_goto);
                        insn_buf[6] = BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_AX, stack_off_cnt);
                        cnt = 7;

                        new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
                        if (!new_prog)
                                return -ENOMEM;

                        delta += cnt - 1;
                        env->prog = prog = new_prog;
                        insn = new_prog->insnsi + i + delta;
                        goto next_insn;
                } else if (bpf_is_may_goto_insn(insn)) {
                        int stack_off = -stack_depth - 8;

                        stack_depth_extra = 8;
                        insn_buf[0] = BPF_LDX_MEM(BPF_DW, BPF_REG_AX, BPF_REG_10, stack_off);
                        if (insn->off >= 0)
                                insn_buf[1] = BPF_JMP_IMM(BPF_JEQ, BPF_REG_AX, 0, insn->off + 2);
                        else
                                insn_buf[1] = BPF_JMP_IMM(BPF_JEQ, BPF_REG_AX, 0, insn->off - 1);
                        insn_buf[2] = BPF_ALU64_IMM(BPF_SUB, BPF_REG_AX, 1);
                        insn_buf[3] = BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_AX, stack_off);
                        cnt = 4;

                        new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
                        if (!new_prog)
                                return -ENOMEM;

                        delta += cnt - 1;
                        env->prog = prog = new_prog;
                        insn = new_prog->insnsi + i + delta;
                        goto next_insn;
                }

                if (insn->code != (BPF_JMP | BPF_CALL))
                        goto next_insn;
                if (insn->src_reg == BPF_PSEUDO_CALL)
                        goto next_insn;
                if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) {
                        ret = bpf_fixup_kfunc_call(env, insn, insn_buf, i + delta, &cnt);
                        if (ret)
                                return ret;
                        if (cnt == 0)
                                goto next_insn;

                        new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
                        if (!new_prog)
                                return -ENOMEM;

                        delta    += cnt - 1;
                        env->prog = prog = new_prog;
                        insn      = new_prog->insnsi + i + delta;
                        goto next_insn;
                }

                /* Skip inlining the helper call if the JIT does it. */
                if (bpf_jit_inlines_helper_call(insn->imm))
                        goto next_insn;

                if (insn->imm == BPF_FUNC_get_route_realm)
                        prog->dst_needed = 1;
                if (insn->imm == BPF_FUNC_get_prandom_u32)
                        bpf_user_rnd_init_once();
                if (insn->imm == BPF_FUNC_override_return)
                        prog->kprobe_override = 1;
                if (insn->imm == BPF_FUNC_tail_call) {
                        /* If we tail call into other programs, we
                         * cannot make any assumptions since they can
                         * be replaced dynamically during runtime in
                         * the program array.
                         */
                        prog->cb_access = 1;
                        if (!bpf_allow_tail_call_in_subprogs(env))
                                prog->aux->stack_depth = MAX_BPF_STACK;
                        prog->aux->max_pkt_offset = MAX_PACKET_OFF;

                        /* mark bpf_tail_call as different opcode to avoid
                         * conditional branch in the interpreter for every normal
                         * call and to prevent accidental JITing by JIT compiler
                         * that doesn't support bpf_tail_call yet
                         */
                        insn->imm = 0;
                        insn->code = BPF_JMP | BPF_TAIL_CALL;

                        aux = &env->insn_aux_data[i + delta];
                        if (env->bpf_capable && !prog->blinding_requested &&
                            prog->jit_requested &&
                            !bpf_map_key_poisoned(aux) &&
                            !bpf_map_ptr_poisoned(aux) &&
                            !bpf_map_ptr_unpriv(aux)) {
                                struct bpf_jit_poke_descriptor desc = {
                                        .reason = BPF_POKE_REASON_TAIL_CALL,
                                        .tail_call.map = aux->map_ptr_state.map_ptr,
                                        .tail_call.key = bpf_map_key_immediate(aux),
                                        .insn_idx = i + delta,
                                };

                                ret = bpf_jit_add_poke_descriptor(prog, &desc);
                                if (ret < 0) {
                                        verbose(env, "adding tail call poke descriptor failed\n");
                                        return ret;
                                }

                                insn->imm = ret + 1;
                                goto next_insn;
                        }

                        if (!bpf_map_ptr_unpriv(aux))
                                goto next_insn;

                        /* instead of changing every JIT dealing with tail_call
                         * emit two extra insns:
                         * if (index >= max_entries) goto out;
                         * index &= array->index_mask;
                         * to avoid out-of-bounds cpu speculation
                         */
                        if (bpf_map_ptr_poisoned(aux)) {
                                verbose(env, "tail_call abusing map_ptr\n");
                                return -EINVAL;
                        }

                        map_ptr = aux->map_ptr_state.map_ptr;
                        insn_buf[0] = BPF_JMP_IMM(BPF_JGE, BPF_REG_3,
                                                  map_ptr->max_entries, 2);
                        insn_buf[1] = BPF_ALU32_IMM(BPF_AND, BPF_REG_3,
                                                    container_of(map_ptr,
                                                                 struct bpf_array,
                                                                 map)->index_mask);
                        insn_buf[2] = *insn;
                        cnt = 3;
                        new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
                        if (!new_prog)
                                return -ENOMEM;

                        delta    += cnt - 1;
                        env->prog = prog = new_prog;
                        insn      = new_prog->insnsi + i + delta;
                        goto next_insn;
                }

                if (insn->imm == BPF_FUNC_timer_set_callback) {
                        /* The verifier will process callback_fn as many times as necessary
                         * with different maps and the register states prepared by
                         * set_timer_callback_state will be accurate.
                         *
                         * The following use case is valid:
                         *   map1 is shared by prog1, prog2, prog3.
                         *   prog1 calls bpf_timer_init for some map1 elements
                         *   prog2 calls bpf_timer_set_callback for some map1 elements.
                         *     Those that were not bpf_timer_init-ed will return -EINVAL.
                         *   prog3 calls bpf_timer_start for some map1 elements.
                         *     Those that were not both bpf_timer_init-ed and
                         *     bpf_timer_set_callback-ed will return -EINVAL.
                         */
                        struct bpf_insn ld_addrs[2] = {
                                BPF_LD_IMM64(BPF_REG_3, (long)prog->aux),
                        };

                        insn_buf[0] = ld_addrs[0];
                        insn_buf[1] = ld_addrs[1];
                        insn_buf[2] = *insn;
                        cnt = 3;

                        new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
                        if (!new_prog)
                                return -ENOMEM;

                        delta    += cnt - 1;
                        env->prog = prog = new_prog;
                        insn      = new_prog->insnsi + i + delta;
                        goto patch_call_imm;
                }

                /* bpf_per_cpu_ptr() and bpf_this_cpu_ptr() */
                if (env->insn_aux_data[i + delta].call_with_percpu_alloc_ptr) {
                        /* patch with 'r1 = *(u64 *)(r1 + 0)' since for percpu data,
                         * bpf_mem_alloc() returns a ptr to the percpu data ptr.
                         */
                        insn_buf[0] = BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_1, 0);
                        insn_buf[1] = *insn;
                        cnt = 2;

                        new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
                        if (!new_prog)
                                return -ENOMEM;

                        delta += cnt - 1;
                        env->prog = prog = new_prog;
                        insn = new_prog->insnsi + i + delta;
                        goto patch_call_imm;
                }

                /* BPF_EMIT_CALL() assumptions in some of the map_gen_lookup
                 * and other inlining handlers are currently limited to 64 bit
                 * only.
                 */
                if (prog->jit_requested && BITS_PER_LONG == 64 &&
                    (insn->imm == BPF_FUNC_map_lookup_elem ||
                     insn->imm == BPF_FUNC_map_update_elem ||
                     insn->imm == BPF_FUNC_map_delete_elem ||
                     insn->imm == BPF_FUNC_map_push_elem   ||
                     insn->imm == BPF_FUNC_map_pop_elem    ||
                     insn->imm == BPF_FUNC_map_peek_elem   ||
                     insn->imm == BPF_FUNC_redirect_map    ||
                     insn->imm == BPF_FUNC_for_each_map_elem ||
                     insn->imm == BPF_FUNC_map_lookup_percpu_elem)) {
                        aux = &env->insn_aux_data[i + delta];
                        if (bpf_map_ptr_poisoned(aux))
                                goto patch_call_imm;

                        map_ptr = aux->map_ptr_state.map_ptr;
                        ops = map_ptr->ops;
                        if (insn->imm == BPF_FUNC_map_lookup_elem &&
                            ops->map_gen_lookup) {
                                cnt = ops->map_gen_lookup(map_ptr, insn_buf);
                                if (cnt == -EOPNOTSUPP)
                                        goto patch_map_ops_generic;
                                if (cnt <= 0 || cnt >= INSN_BUF_SIZE) {
                                        verifier_bug(env, "%d insns generated for map lookup", cnt);
                                        return -EFAULT;
                                }

                                new_prog = bpf_patch_insn_data(env, i + delta,
                                                               insn_buf, cnt);
                                if (!new_prog)
                                        return -ENOMEM;

                                delta    += cnt - 1;
                                env->prog = prog = new_prog;
                                insn      = new_prog->insnsi + i + delta;
                                goto next_insn;
                        }

                        BUILD_BUG_ON(!__same_type(ops->map_lookup_elem,
                                     (void *(*)(struct bpf_map *map, void *key))NULL));
                        BUILD_BUG_ON(!__same_type(ops->map_delete_elem,
                                     (long (*)(struct bpf_map *map, void *key))NULL));
                        BUILD_BUG_ON(!__same_type(ops->map_update_elem,
                                     (long (*)(struct bpf_map *map, void *key, void *value,
                                              u64 flags))NULL));
                        BUILD_BUG_ON(!__same_type(ops->map_push_elem,
                                     (long (*)(struct bpf_map *map, void *value,
                                              u64 flags))NULL));
                        BUILD_BUG_ON(!__same_type(ops->map_pop_elem,
                                     (long (*)(struct bpf_map *map, void *value))NULL));
                        BUILD_BUG_ON(!__same_type(ops->map_peek_elem,
                                     (long (*)(struct bpf_map *map, void *value))NULL));
                        BUILD_BUG_ON(!__same_type(ops->map_redirect,
                                     (long (*)(struct bpf_map *map, u64 index, u64 flags))NULL));
                        BUILD_BUG_ON(!__same_type(ops->map_for_each_callback,
                                     (long (*)(struct bpf_map *map,
                                              bpf_callback_t callback_fn,
                                              void *callback_ctx,
                                              u64 flags))NULL));
                        BUILD_BUG_ON(!__same_type(ops->map_lookup_percpu_elem,
                                     (void *(*)(struct bpf_map *map, void *key, u32 cpu))NULL));

patch_map_ops_generic:
                        switch (insn->imm) {
                        case BPF_FUNC_map_lookup_elem:
                                insn->imm = BPF_CALL_IMM(ops->map_lookup_elem);
                                goto next_insn;
                        case BPF_FUNC_map_update_elem:
                                insn->imm = BPF_CALL_IMM(ops->map_update_elem);
                                goto next_insn;
                        case BPF_FUNC_map_delete_elem:
                                insn->imm = BPF_CALL_IMM(ops->map_delete_elem);
                                goto next_insn;
                        case BPF_FUNC_map_push_elem:
                                insn->imm = BPF_CALL_IMM(ops->map_push_elem);
                                goto next_insn;
                        case BPF_FUNC_map_pop_elem:
                                insn->imm = BPF_CALL_IMM(ops->map_pop_elem);
                                goto next_insn;
                        case BPF_FUNC_map_peek_elem:
                                insn->imm = BPF_CALL_IMM(ops->map_peek_elem);
                                goto next_insn;
                        case BPF_FUNC_redirect_map:
                                insn->imm = BPF_CALL_IMM(ops->map_redirect);
                                goto next_insn;
                        case BPF_FUNC_for_each_map_elem:
                                insn->imm = BPF_CALL_IMM(ops->map_for_each_callback);
                                goto next_insn;
                        case BPF_FUNC_map_lookup_percpu_elem:
                                insn->imm = BPF_CALL_IMM(ops->map_lookup_percpu_elem);
                                goto next_insn;
                        }

                        goto patch_call_imm;
                }

                /* Implement bpf_jiffies64 inline. */
                if (prog->jit_requested && BITS_PER_LONG == 64 &&
                    insn->imm == BPF_FUNC_jiffies64) {
                        struct bpf_insn ld_jiffies_addr[2] = {
                                BPF_LD_IMM64(BPF_REG_0,
                                             (unsigned long)&jiffies),
                        };

                        insn_buf[0] = ld_jiffies_addr[0];
                        insn_buf[1] = ld_jiffies_addr[1];
                        insn_buf[2] = BPF_LDX_MEM(BPF_DW, BPF_REG_0,
                                                  BPF_REG_0, 0);
                        cnt = 3;

                        new_prog = bpf_patch_insn_data(env, i + delta, insn_buf,
                                                       cnt);
                        if (!new_prog)
                                return -ENOMEM;

                        delta    += cnt - 1;
                        env->prog = prog = new_prog;
                        insn      = new_prog->insnsi + i + delta;
                        goto next_insn;
                }

#if defined(CONFIG_X86_64) && !defined(CONFIG_UML)
                /* Implement bpf_get_smp_processor_id() inline. */
                if (insn->imm == BPF_FUNC_get_smp_processor_id &&
                    bpf_verifier_inlines_helper_call(env, insn->imm)) {
                        /* BPF_FUNC_get_smp_processor_id inlining is an
                         * optimization, so if cpu_number is ever
                         * changed in some incompatible and hard to support
                         * way, it's fine to back out this inlining logic
                         */
#ifdef CONFIG_SMP
                        insn_buf[0] = BPF_MOV64_IMM(BPF_REG_0, (u32)(unsigned long)&cpu_number);
                        insn_buf[1] = BPF_MOV64_PERCPU_REG(BPF_REG_0, BPF_REG_0);
                        insn_buf[2] = BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_0, 0);
                        cnt = 3;
#else
                        insn_buf[0] = BPF_ALU32_REG(BPF_XOR, BPF_REG_0, BPF_REG_0);
                        cnt = 1;
#endif
                        new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
                        if (!new_prog)
                                return -ENOMEM;

                        delta    += cnt - 1;
                        env->prog = prog = new_prog;
                        insn      = new_prog->insnsi + i + delta;
                        goto next_insn;
                }

                /* Implement bpf_get_current_task() and bpf_get_current_task_btf() inline. */
                if ((insn->imm == BPF_FUNC_get_current_task || insn->imm == BPF_FUNC_get_current_task_btf) &&
                    bpf_verifier_inlines_helper_call(env, insn->imm)) {
                        insn_buf[0] = BPF_MOV64_IMM(BPF_REG_0, (u32)(unsigned long)&current_task);
                        insn_buf[1] = BPF_MOV64_PERCPU_REG(BPF_REG_0, BPF_REG_0);
                        insn_buf[2] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_0, 0);
                        cnt = 3;

                        new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
                        if (!new_prog)
                                return -ENOMEM;

                        delta    += cnt - 1;
                        env->prog = prog = new_prog;
                        insn      = new_prog->insnsi + i + delta;
                        goto next_insn;
                }
#endif
                /* Implement bpf_get_func_arg inline. */
                if (prog_type == BPF_PROG_TYPE_TRACING &&
                    insn->imm == BPF_FUNC_get_func_arg) {
                        if (eatype == BPF_TRACE_RAW_TP) {
                                int nr_args = btf_type_vlen(prog->aux->attach_func_proto);

                                /* skip 'void *__data' in btf_trace_##name() and save to reg0 */
                                insn_buf[0] = BPF_MOV64_IMM(BPF_REG_0, nr_args - 1);
                                cnt = 1;
                        } else {
                                /* Load nr_args from ctx - 8 */
                                insn_buf[0] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8);
                                insn_buf[1] = BPF_ALU64_IMM(BPF_AND, BPF_REG_0, 0xFF);
                                cnt = 2;
                        }
                        insn_buf[cnt++] = BPF_JMP32_REG(BPF_JGE, BPF_REG_2, BPF_REG_0, 6);
                        insn_buf[cnt++] = BPF_ALU64_IMM(BPF_LSH, BPF_REG_2, 3);
                        insn_buf[cnt++] = BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_1);
                        insn_buf[cnt++] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_2, 0);
                        insn_buf[cnt++] = BPF_STX_MEM(BPF_DW, BPF_REG_3, BPF_REG_0, 0);
                        insn_buf[cnt++] = BPF_MOV64_IMM(BPF_REG_0, 0);
                        insn_buf[cnt++] = BPF_JMP_A(1);
                        insn_buf[cnt++] = BPF_MOV64_IMM(BPF_REG_0, -EINVAL);

                        new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
                        if (!new_prog)
                                return -ENOMEM;

                        delta    += cnt - 1;
                        env->prog = prog = new_prog;
                        insn      = new_prog->insnsi + i + delta;
                        goto next_insn;
                }

                /* Implement bpf_get_func_ret inline. */
                if (prog_type == BPF_PROG_TYPE_TRACING &&
                    insn->imm == BPF_FUNC_get_func_ret) {
                        if (eatype == BPF_TRACE_FEXIT ||
                            eatype == BPF_TRACE_FSESSION ||
                            eatype == BPF_MODIFY_RETURN) {
                                /* Load nr_args from ctx - 8 */
                                insn_buf[0] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8);
                                insn_buf[1] = BPF_ALU64_IMM(BPF_AND, BPF_REG_0, 0xFF);
                                insn_buf[2] = BPF_ALU64_IMM(BPF_LSH, BPF_REG_0, 3);
                                insn_buf[3] = BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1);
                                insn_buf[4] = BPF_LDX_MEM(BPF_DW, BPF_REG_3, BPF_REG_0, 0);
                                insn_buf[5] = BPF_STX_MEM(BPF_DW, BPF_REG_2, BPF_REG_3, 0);
                                insn_buf[6] = BPF_MOV64_IMM(BPF_REG_0, 0);
                                cnt = 7;
                        } else {
                                insn_buf[0] = BPF_MOV64_IMM(BPF_REG_0, -EOPNOTSUPP);
                                cnt = 1;
                        }

                        new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
                        if (!new_prog)
                                return -ENOMEM;

                        delta    += cnt - 1;
                        env->prog = prog = new_prog;
                        insn      = new_prog->insnsi + i + delta;
                        goto next_insn;
                }

                /* Implement get_func_arg_cnt inline. */
                if (prog_type == BPF_PROG_TYPE_TRACING &&
                    insn->imm == BPF_FUNC_get_func_arg_cnt) {
                        if (eatype == BPF_TRACE_RAW_TP) {
                                int nr_args = btf_type_vlen(prog->aux->attach_func_proto);

                                /* skip 'void *__data' in btf_trace_##name() and save to reg0 */
                                insn_buf[0] = BPF_MOV64_IMM(BPF_REG_0, nr_args - 1);
                                cnt = 1;
                        } else {
                                /* Load nr_args from ctx - 8 */
                                insn_buf[0] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8);
                                insn_buf[1] = BPF_ALU64_IMM(BPF_AND, BPF_REG_0, 0xFF);
                                cnt = 2;
                        }

                        new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
                        if (!new_prog)
                                return -ENOMEM;

                        delta    += cnt - 1;
                        env->prog = prog = new_prog;
                        insn      = new_prog->insnsi + i + delta;
                        goto next_insn;
                }

                /* Implement bpf_get_func_ip inline. */
                if (prog_type == BPF_PROG_TYPE_TRACING &&
                    insn->imm == BPF_FUNC_get_func_ip) {
                        /* Load IP address from ctx - 16 */
                        insn_buf[0] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -16);

                        new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, 1);
                        if (!new_prog)
                                return -ENOMEM;

                        env->prog = prog = new_prog;
                        insn      = new_prog->insnsi + i + delta;
                        goto next_insn;
                }

                /* Implement bpf_get_branch_snapshot inline. */
                if (IS_ENABLED(CONFIG_PERF_EVENTS) &&
                    prog->jit_requested && BITS_PER_LONG == 64 &&
                    insn->imm == BPF_FUNC_get_branch_snapshot) {
                        /* We are dealing with the following func protos:
                         * u64 bpf_get_branch_snapshot(void *buf, u32 size, u64 flags);
                         * int perf_snapshot_branch_stack(struct perf_branch_entry *entries, u32 cnt);
                         */
                        const u32 br_entry_size = sizeof(struct perf_branch_entry);

                        /* struct perf_branch_entry is part of UAPI and is
                         * used as an array element, so extremely unlikely to
                         * ever grow or shrink
                         */
                        BUILD_BUG_ON(br_entry_size != 24);

                        /* if (unlikely(flags)) return -EINVAL */
                        insn_buf[0] = BPF_JMP_IMM(BPF_JNE, BPF_REG_3, 0, 7);

                        /* Transform size (bytes) into number of entries (cnt = size / 24).
                         * But to avoid expensive division instruction, we implement
                         * divide-by-3 through multiplication, followed by further
                         * division by 8 through 3-bit right shift.
                         * Refer to book "Hacker's Delight, 2nd ed." by Henry S. Warren, Jr.,
                         * p. 227, chapter "Unsigned Division by 3" for details and proofs.
                         *
                         * N / 3 <=> M * N / 2^33, where M = (2^33 + 1) / 3 = 0xaaaaaaab.
                         */
                        insn_buf[1] = BPF_MOV32_IMM(BPF_REG_0, 0xaaaaaaab);
                        insn_buf[2] = BPF_ALU64_REG(BPF_MUL, BPF_REG_2, BPF_REG_0);
                        insn_buf[3] = BPF_ALU64_IMM(BPF_RSH, BPF_REG_2, 36);

                        /* call perf_snapshot_branch_stack implementation */
                        insn_buf[4] = BPF_EMIT_CALL(static_call_query(perf_snapshot_branch_stack));
                        /* if (entry_cnt == 0) return -ENOENT */
                        insn_buf[5] = BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 4);
                        /* return entry_cnt * sizeof(struct perf_branch_entry) */
                        insn_buf[6] = BPF_ALU32_IMM(BPF_MUL, BPF_REG_0, br_entry_size);
                        insn_buf[7] = BPF_JMP_A(3);
                        /* return -EINVAL; */
                        insn_buf[8] = BPF_MOV64_IMM(BPF_REG_0, -EINVAL);
                        insn_buf[9] = BPF_JMP_A(1);
                        /* return -ENOENT; */
                        insn_buf[10] = BPF_MOV64_IMM(BPF_REG_0, -ENOENT);
                        cnt = 11;

                        new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
                        if (!new_prog)
                                return -ENOMEM;

                        delta    += cnt - 1;
                        env->prog = prog = new_prog;
                        insn      = new_prog->insnsi + i + delta;
                        goto next_insn;
                }

                /* Implement bpf_kptr_xchg inline */
                if (prog->jit_requested && BITS_PER_LONG == 64 &&
                    insn->imm == BPF_FUNC_kptr_xchg &&
                    bpf_jit_supports_ptr_xchg()) {
                        insn_buf[0] = BPF_MOV64_REG(BPF_REG_0, BPF_REG_2);
                        insn_buf[1] = BPF_ATOMIC_OP(BPF_DW, BPF_XCHG, BPF_REG_1, BPF_REG_0, 0);
                        cnt = 2;

                        new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
                        if (!new_prog)
                                return -ENOMEM;

                        delta    += cnt - 1;
                        env->prog = prog = new_prog;
                        insn      = new_prog->insnsi + i + delta;
                        goto next_insn;
                }
patch_call_imm:
                fn = env->ops->get_func_proto(insn->imm, env->prog);
                /* all functions that have prototype and verifier allowed
                 * programs to call them, must be real in-kernel functions
                 */
                if (!fn->func) {
                        verifier_bug(env,
                                     "not inlined functions %s#%d is missing func",
                                     func_id_name(insn->imm), insn->imm);
                        return -EFAULT;
                }
                insn->imm = fn->func - __bpf_call_base;
next_insn:
                if (subprogs[cur_subprog + 1].start == i + delta + 1) {
                        subprogs[cur_subprog].stack_depth += stack_depth_extra;
                        subprogs[cur_subprog].stack_extra = stack_depth_extra;

                        stack_depth = subprogs[cur_subprog].stack_depth;
                        if (stack_depth > MAX_BPF_STACK && !prog->jit_requested) {
                                verbose(env, "stack size %d(extra %d) is too large\n",
                                        stack_depth, stack_depth_extra);
                                return -EINVAL;
                        }
                        cur_subprog++;
                        stack_depth = subprogs[cur_subprog].stack_depth;
                        stack_depth_extra = 0;
                }
                i++;
                insn++;
        }

        env->prog->aux->stack_depth = subprogs[0].stack_depth;
        for (i = 0; i < env->subprog_cnt; i++) {
                int delta = bpf_jit_supports_timed_may_goto() ? 2 : 1;
                int subprog_start = subprogs[i].start;
                int stack_slots = subprogs[i].stack_extra / 8;
                int slots = delta, cnt = 0;

                if (!stack_slots)
                        continue;
                /* We need two slots in case timed may_goto is supported. */
                if (stack_slots > slots) {
                        verifier_bug(env, "stack_slots supports may_goto only");
                        return -EFAULT;
                }

                stack_depth = subprogs[i].stack_depth;
                if (bpf_jit_supports_timed_may_goto()) {
                        insn_buf[cnt++] = BPF_ST_MEM(BPF_DW, BPF_REG_FP, -stack_depth,
                                                     BPF_MAX_TIMED_LOOPS);
                        insn_buf[cnt++] = BPF_ST_MEM(BPF_DW, BPF_REG_FP, -stack_depth + 8, 0);
                } else {
                        /* Add ST insn to subprog prologue to init extra stack */
                        insn_buf[cnt++] = BPF_ST_MEM(BPF_DW, BPF_REG_FP, -stack_depth,
                                                     BPF_MAX_LOOPS);
                }
                /* Copy first actual insn to preserve it */
                insn_buf[cnt++] = env->prog->insnsi[subprog_start];

                new_prog = bpf_patch_insn_data(env, subprog_start, insn_buf, cnt);
                if (!new_prog)
                        return -ENOMEM;
                env->prog = prog = new_prog;
                /*
                 * If may_goto is a first insn of a prog there could be a jmp
                 * insn that points to it, hence adjust all such jmps to point
                 * to insn after BPF_ST that inits may_goto count.
                 * Adjustment will succeed because bpf_patch_insn_data() didn't fail.
                 */
                WARN_ON(adjust_jmp_off(env->prog, subprog_start, delta));
        }

        /* Since poke tab is now finalized, publish aux to tracker. */
        for (i = 0; i < prog->aux->size_poke_tab; i++) {
                map_ptr = prog->aux->poke_tab[i].tail_call.map;
                if (!map_ptr->ops->map_poke_track ||
                    !map_ptr->ops->map_poke_untrack ||
                    !map_ptr->ops->map_poke_run) {
                        verifier_bug(env, "poke tab is misconfigured");
                        return -EFAULT;
                }

                ret = map_ptr->ops->map_poke_track(map_ptr, prog->aux);
                if (ret < 0) {
                        verbose(env, "tracking tail call prog failed\n");
                        return ret;
                }
        }

        ret = sort_kfunc_descs_by_imm_off(env);
        if (ret)
                return ret;

        return 0;
}

static struct bpf_prog *inline_bpf_loop(struct bpf_verifier_env *env,
                                        int position,
                                        s32 stack_base,
                                        u32 callback_subprogno,
                                        u32 *total_cnt)
{
        s32 r6_offset = stack_base + 0 * BPF_REG_SIZE;
        s32 r7_offset = stack_base + 1 * BPF_REG_SIZE;
        s32 r8_offset = stack_base + 2 * BPF_REG_SIZE;
        int reg_loop_max = BPF_REG_6;
        int reg_loop_cnt = BPF_REG_7;
        int reg_loop_ctx = BPF_REG_8;

        struct bpf_insn *insn_buf = env->insn_buf;
        struct bpf_prog *new_prog;
        u32 callback_start;
        u32 call_insn_offset;
        s32 callback_offset;
        u32 cnt = 0;

        /* This represents an inlined version of bpf_iter.c:bpf_loop,
         * be careful to modify this code in sync.
         */

        /* Return error and jump to the end of the patch if
         * expected number of iterations is too big.
         */
        insn_buf[cnt++] = BPF_JMP_IMM(BPF_JLE, BPF_REG_1, BPF_MAX_LOOPS, 2);
        insn_buf[cnt++] = BPF_MOV32_IMM(BPF_REG_0, -E2BIG);
        insn_buf[cnt++] = BPF_JMP_IMM(BPF_JA, 0, 0, 16);
        /* spill R6, R7, R8 to use these as loop vars */
        insn_buf[cnt++] = BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_6, r6_offset);
        insn_buf[cnt++] = BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_7, r7_offset);
        insn_buf[cnt++] = BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_8, r8_offset);
        /* initialize loop vars */
        insn_buf[cnt++] = BPF_MOV64_REG(reg_loop_max, BPF_REG_1);
        insn_buf[cnt++] = BPF_MOV32_IMM(reg_loop_cnt, 0);
        insn_buf[cnt++] = BPF_MOV64_REG(reg_loop_ctx, BPF_REG_3);
        /* loop header,
         * if reg_loop_cnt >= reg_loop_max skip the loop body
         */
        insn_buf[cnt++] = BPF_JMP_REG(BPF_JGE, reg_loop_cnt, reg_loop_max, 5);
        /* callback call,
         * correct callback offset would be set after patching
         */
        insn_buf[cnt++] = BPF_MOV64_REG(BPF_REG_1, reg_loop_cnt);
        insn_buf[cnt++] = BPF_MOV64_REG(BPF_REG_2, reg_loop_ctx);
        insn_buf[cnt++] = BPF_CALL_REL(0);
        /* increment loop counter */
        insn_buf[cnt++] = BPF_ALU64_IMM(BPF_ADD, reg_loop_cnt, 1);
        /* jump to loop header if callback returned 0 */
        insn_buf[cnt++] = BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, -6);
        /* return value of bpf_loop,
         * set R0 to the number of iterations
         */
        insn_buf[cnt++] = BPF_MOV64_REG(BPF_REG_0, reg_loop_cnt);
        /* restore original values of R6, R7, R8 */
        insn_buf[cnt++] = BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_10, r6_offset);
        insn_buf[cnt++] = BPF_LDX_MEM(BPF_DW, BPF_REG_7, BPF_REG_10, r7_offset);
        insn_buf[cnt++] = BPF_LDX_MEM(BPF_DW, BPF_REG_8, BPF_REG_10, r8_offset);

        *total_cnt = cnt;
        new_prog = bpf_patch_insn_data(env, position, insn_buf, cnt);
        if (!new_prog)
                return new_prog;

        /* callback start is known only after patching */
        callback_start = env->subprog_info[callback_subprogno].start;
        /* Note: insn_buf[12] is an offset of BPF_CALL_REL instruction */
        call_insn_offset = position + 12;
        callback_offset = callback_start - call_insn_offset - 1;
        new_prog->insnsi[call_insn_offset].imm = callback_offset;

        return new_prog;
}

static bool is_bpf_loop_call(struct bpf_insn *insn)
{
        return insn->code == (BPF_JMP | BPF_CALL) &&
                insn->src_reg == 0 &&
                insn->imm == BPF_FUNC_loop;
}

/* For all sub-programs in the program (including main) check
 * insn_aux_data to see if there are bpf_loop calls that require
 * inlining. If such calls are found the calls are replaced with a
 * sequence of instructions produced by `inline_bpf_loop` function and
 * subprog stack_depth is increased by the size of 3 registers.
 * This stack space is used to spill values of the R6, R7, R8.  These
 * registers are used to store the loop bound, counter and context
 * variables.
 */
int bpf_optimize_bpf_loop(struct bpf_verifier_env *env)
{
        struct bpf_subprog_info *subprogs = env->subprog_info;
        int i, cur_subprog = 0, cnt, delta = 0;
        struct bpf_insn *insn = env->prog->insnsi;
        int insn_cnt = env->prog->len;
        u16 stack_depth = subprogs[cur_subprog].stack_depth;
        u16 stack_depth_roundup = round_up(stack_depth, 8) - stack_depth;
        u16 stack_depth_extra = 0;

        for (i = 0; i < insn_cnt; i++, insn++) {
                struct bpf_loop_inline_state *inline_state =
                        &env->insn_aux_data[i + delta].loop_inline_state;

                if (is_bpf_loop_call(insn) && inline_state->fit_for_inline) {
                        struct bpf_prog *new_prog;

                        stack_depth_extra = BPF_REG_SIZE * 3 + stack_depth_roundup;
                        new_prog = inline_bpf_loop(env,
                                                   i + delta,
                                                   -(stack_depth + stack_depth_extra),
                                                   inline_state->callback_subprogno,
                                                   &cnt);
                        if (!new_prog)
                                return -ENOMEM;

                        delta     += cnt - 1;
                        env->prog  = new_prog;
                        insn       = new_prog->insnsi + i + delta;
                }

                if (subprogs[cur_subprog + 1].start == i + delta + 1) {
                        subprogs[cur_subprog].stack_depth += stack_depth_extra;
                        cur_subprog++;
                        stack_depth = subprogs[cur_subprog].stack_depth;
                        stack_depth_roundup = round_up(stack_depth, 8) - stack_depth;
                        stack_depth_extra = 0;
                }
        }

        env->prog->aux->stack_depth = env->subprog_info[0].stack_depth;

        return 0;
}

/* Remove unnecessary spill/fill pairs, members of fastcall pattern,
 * adjust subprograms stack depth when possible.
 */
int bpf_remove_fastcall_spills_fills(struct bpf_verifier_env *env)
{
        struct bpf_subprog_info *subprog = env->subprog_info;
        struct bpf_insn_aux_data *aux = env->insn_aux_data;
        struct bpf_insn *insn = env->prog->insnsi;
        int insn_cnt = env->prog->len;
        u32 spills_num;
        bool modified = false;
        int i, j;

        for (i = 0; i < insn_cnt; i++, insn++) {
                if (aux[i].fastcall_spills_num > 0) {
                        spills_num = aux[i].fastcall_spills_num;
                        /* NOPs would be removed by opt_remove_nops() */
                        for (j = 1; j <= spills_num; ++j) {
                                *(insn - j) = NOP;
                                *(insn + j) = NOP;
                        }
                        modified = true;
                }
                if ((subprog + 1)->start == i + 1) {
                        if (modified && !subprog->keep_fastcall_stack)
                                subprog->stack_depth = -subprog->fastcall_stack_off;
                        subprog++;
                        modified = false;
                }
        }

        return 0;
}