// SPDX-License-Identifier: GPL-2.0
/*
 * Code for replacing ftrace calls with jumps.
 *
 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
 *
 * Thanks goes out to P.A. Semi, Inc for supplying me with a PPC64 box.
 *
 * Added function graph tracer code, taken from x86 that was written
 * by Frederic Weisbecker, and ported to PPC by Steven Rostedt.
 *
 */

#define pr_fmt(fmt) "ftrace-powerpc: " fmt

#include <linux/spinlock.h>
#include <linux/hardirq.h>
#include <linux/uaccess.h>
#include <linux/module.h>
#include <linux/ftrace.h>
#include <linux/percpu.h>
#include <linux/init.h>
#include <linux/list.h>

#include <asm/cacheflush.h>
#include <asm/text-patching.h>
#include <asm/ftrace.h>
#include <asm/syscall.h>
#include <asm/inst.h>
#include <asm/sections.h>

#define NUM_FTRACE_TRAMPS       2
static unsigned long ftrace_tramps[NUM_FTRACE_TRAMPS];

unsigned long ftrace_call_adjust(unsigned long addr)
{
        if (addr >= (unsigned long)__exittext_begin && addr < (unsigned long)__exittext_end)
                return 0;

        if (IS_ENABLED(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY)) {
                if (!IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE)) {
                        addr += MCOUNT_INSN_SIZE;
                        if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS))
                                addr += MCOUNT_INSN_SIZE;
                } else if (IS_ENABLED(CONFIG_CC_IS_CLANG) && IS_ENABLED(CONFIG_PPC64)) {
                        /*
                         * addr points to global entry point though the NOP was emitted at local
                         * entry point due to https://github.com/llvm/llvm-project/issues/163706
                         * Handle that here with ppc_function_entry() for kernel symbols while
                         * adjusting module addresses in the else case, by looking for the below
                         * module global entry point sequence:
                         *      ld    r2, -8(r12)
                         *      add   r2, r2, r12
                         */
                        if (is_kernel_text(addr) || is_kernel_inittext(addr))
                                addr = ppc_function_entry((void *)addr);
                        else if ((ppc_inst_val(ppc_inst_read((u32 *)addr)) ==
                                  PPC_RAW_LD(_R2, _R12, -8)) &&
                                 (ppc_inst_val(ppc_inst_read((u32 *)(addr+4))) ==
                                  PPC_RAW_ADD(_R2, _R2, _R12)))
                                addr += 8;
                }
        }

        return addr;
}

static ppc_inst_t ftrace_create_branch_inst(unsigned long ip, unsigned long addr, int link)
{
        ppc_inst_t op;

        WARN_ON(!is_offset_in_branch_range(addr - ip));
        create_branch(&op, (u32 *)ip, addr, link ? BRANCH_SET_LINK : 0);

        return op;
}

static inline int ftrace_read_inst(unsigned long ip, ppc_inst_t *op)
{
        if (copy_inst_from_kernel_nofault(op, (void *)ip)) {
                pr_err("0x%lx: fetching instruction failed\n", ip);
                return -EFAULT;
        }

        return 0;
}

static inline int ftrace_validate_inst(unsigned long ip, ppc_inst_t inst)
{
        ppc_inst_t op;
        int ret;

        ret = ftrace_read_inst(ip, &op);
        if (!ret && !ppc_inst_equal(op, inst)) {
                pr_err("0x%lx: expected (%08lx) != found (%08lx)\n",
                       ip, ppc_inst_as_ulong(inst), ppc_inst_as_ulong(op));
                ret = -EINVAL;
        }

        return ret;
}

static inline int ftrace_modify_code(unsigned long ip, ppc_inst_t old, ppc_inst_t new)
{
        int ret = ftrace_validate_inst(ip, old);

        if (!ret && !ppc_inst_equal(old, new))
                ret = patch_instruction((u32 *)ip, new);

        return ret;
}

static int is_bl_op(ppc_inst_t op)
{
        return (ppc_inst_val(op) & ~PPC_LI_MASK) == PPC_RAW_BL(0);
}

static unsigned long find_ftrace_tramp(unsigned long ip)
{
        int i;

        for (i = 0; i < NUM_FTRACE_TRAMPS; i++)
                if (!ftrace_tramps[i])
                        continue;
                else if (is_offset_in_branch_range(ftrace_tramps[i] - ip))
                        return ftrace_tramps[i];

        return 0;
}

#ifdef CONFIG_MODULES
static unsigned long ftrace_lookup_module_stub(unsigned long ip, unsigned long addr)
{
        struct module *mod = NULL;

        scoped_guard(rcu)
                mod = __module_text_address(ip);
        if (!mod)
                pr_err("No module loaded at addr=%lx\n", ip);

        return (addr == (unsigned long)ftrace_caller ? mod->arch.tramp : mod->arch.tramp_regs);
}
#else
static unsigned long ftrace_lookup_module_stub(unsigned long ip, unsigned long addr)
{
        return 0;
}
#endif

static unsigned long ftrace_get_ool_stub(struct dyn_ftrace *rec)
{
#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE
        return rec->arch.ool_stub;
#else
        BUILD_BUG();
#endif
}

static int ftrace_get_call_inst(struct dyn_ftrace *rec, unsigned long addr, ppc_inst_t *call_inst)
{
        unsigned long ip;
        unsigned long stub;

        if (IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE))
                ip = ftrace_get_ool_stub(rec) + MCOUNT_INSN_SIZE; /* second instruction in stub */
        else
                ip = rec->ip;

        if (!is_offset_in_branch_range(addr - ip) && addr != FTRACE_ADDR &&
            addr != FTRACE_REGS_ADDR) {
                /* This can only happen with ftrace direct */
                if (!IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS)) {
                        pr_err("0x%lx (0x%lx): Unexpected target address 0x%lx\n",
                               ip, rec->ip, addr);
                        return -EINVAL;
                }
                addr = FTRACE_ADDR;
        }

        if (is_offset_in_branch_range(addr - ip))
                /* Within range */
                stub = addr;
        else if (core_kernel_text(ip))
                /* We would be branching to one of our ftrace stubs */
                stub = find_ftrace_tramp(ip);
        else
                stub = ftrace_lookup_module_stub(ip, addr);

        if (!stub) {
                pr_err("0x%lx (0x%lx): No ftrace stubs reachable\n", ip, rec->ip);
                return -EINVAL;
        }

        *call_inst = ftrace_create_branch_inst(ip, stub, 1);
        return 0;
}

static int ftrace_init_ool_stub(struct module *mod, struct dyn_ftrace *rec)
{
#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE
        static int ool_stub_text_index, ool_stub_text_end_index, ool_stub_inittext_index;
        int ret = 0, ool_stub_count, *ool_stub_index;
        ppc_inst_t inst;
        /*
         * See ftrace_entry.S if changing the below instruction sequence, as we rely on
         * decoding the last branch instruction here to recover the correct function ip.
         */
        struct ftrace_ool_stub *ool_stub, ool_stub_template = {
                .insn = {
                        PPC_RAW_MFLR(_R0),
                        PPC_RAW_NOP(),          /* bl ftrace_caller */
                        PPC_RAW_MTLR(_R0),
                        PPC_RAW_NOP()           /* b rec->ip + 4 */
                }
        };

        WARN_ON(rec->arch.ool_stub);

        if (is_kernel_inittext(rec->ip)) {
                ool_stub = ftrace_ool_stub_inittext;
                ool_stub_index = &ool_stub_inittext_index;
                ool_stub_count = ftrace_ool_stub_inittext_count;
        } else if (is_kernel_text(rec->ip)) {
                /*
                 * ftrace records are sorted, so we first use up the stub area within .text
                 * (ftrace_ool_stub_text) before using the area at the end of .text
                 * (ftrace_ool_stub_text_end), unless the stub is out of range of the record.
                 */
                if (ool_stub_text_index >= ftrace_ool_stub_text_count ||
                    !is_offset_in_branch_range((long)rec->ip -
                                               (long)&ftrace_ool_stub_text[ool_stub_text_index])) {
                        ool_stub = ftrace_ool_stub_text_end;
                        ool_stub_index = &ool_stub_text_end_index;
                        ool_stub_count = ftrace_ool_stub_text_end_count;
                } else {
                        ool_stub = ftrace_ool_stub_text;
                        ool_stub_index = &ool_stub_text_index;
                        ool_stub_count = ftrace_ool_stub_text_count;
                }
#ifdef CONFIG_MODULES
        } else if (mod) {
                ool_stub = mod->arch.ool_stubs;
                ool_stub_index = &mod->arch.ool_stub_index;
                ool_stub_count = mod->arch.ool_stub_count;
#endif
        } else {
                return -EINVAL;
        }

        ool_stub += (*ool_stub_index)++;

        if (WARN_ON(*ool_stub_index > ool_stub_count))
                return -EINVAL;

        if (!is_offset_in_branch_range((long)rec->ip - (long)&ool_stub->insn[0]) ||
            !is_offset_in_branch_range((long)(rec->ip + MCOUNT_INSN_SIZE) -
                                       (long)&ool_stub->insn[3])) {
                pr_err("%s: ftrace ool stub out of range (%p -> %p).\n",
                                        __func__, (void *)rec->ip, (void *)&ool_stub->insn[0]);
                return -EINVAL;
        }

        rec->arch.ool_stub = (unsigned long)&ool_stub->insn[0];

        /* bl ftrace_caller */
        if (!mod)
                ret = ftrace_get_call_inst(rec, (unsigned long)ftrace_caller, &inst);
#ifdef CONFIG_MODULES
        else
                /*
                 * We can't use ftrace_get_call_inst() since that uses
                 * __module_text_address(rec->ip) to look up the module.
                 * But, since the module is not fully formed at this stage,
                 * the lookup fails. We know the target though, so generate
                 * the branch inst directly.
                 */
                inst = ftrace_create_branch_inst(ftrace_get_ool_stub(rec) + MCOUNT_INSN_SIZE,
                                                 mod->arch.tramp, 1);
#endif
        ool_stub_template.insn[1] = ppc_inst_val(inst);

        /* b rec->ip + 4 */
        if (!ret && create_branch(&inst, &ool_stub->insn[3], rec->ip + MCOUNT_INSN_SIZE, 0))
                return -EINVAL;
        ool_stub_template.insn[3] = ppc_inst_val(inst);

        if (!ret)
                ret = patch_instructions((u32 *)ool_stub, (u32 *)&ool_stub_template,
                                         sizeof(ool_stub_template), false);

        return ret;
#else /* !CONFIG_PPC_FTRACE_OUT_OF_LINE */
        BUILD_BUG();
#endif
}

#ifdef CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS
static const struct ftrace_ops *powerpc_rec_get_ops(struct dyn_ftrace *rec)
{
        const struct ftrace_ops *ops = NULL;

        if (rec->flags & FTRACE_FL_CALL_OPS_EN) {
                ops = ftrace_find_unique_ops(rec);
                WARN_ON_ONCE(!ops);
        }

        if (!ops)
                ops = &ftrace_list_ops;

        return ops;
}

static int ftrace_rec_set_ops(struct dyn_ftrace *rec, const struct ftrace_ops *ops)
{
        if (IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE))
                return patch_ulong((void *)(ftrace_get_ool_stub(rec) - sizeof(unsigned long)),
                                   (unsigned long)ops);
        else
                return patch_ulong((void *)(rec->ip - MCOUNT_INSN_SIZE - sizeof(unsigned long)),
                                   (unsigned long)ops);
}

static int ftrace_rec_set_nop_ops(struct dyn_ftrace *rec)
{
        return ftrace_rec_set_ops(rec, &ftrace_nop_ops);
}

static int ftrace_rec_update_ops(struct dyn_ftrace *rec)
{
        return ftrace_rec_set_ops(rec, powerpc_rec_get_ops(rec));
}
#else
static int ftrace_rec_set_nop_ops(struct dyn_ftrace *rec) { return 0; }
static int ftrace_rec_update_ops(struct dyn_ftrace *rec) { return 0; }
#endif

#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned long addr)
{
        /* This should never be called since we override ftrace_replace_code() */
        WARN_ON(1);
        return -EINVAL;
}
#endif

int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
{
        ppc_inst_t old, new;
        unsigned long ip = rec->ip;
        int ret = 0;

        /* This can only ever be called during module load */
        if (WARN_ON(!IS_ENABLED(CONFIG_MODULES) || core_kernel_text(ip)))
                return -EINVAL;

        old = ppc_inst(PPC_RAW_NOP());
        if (IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE)) {
                ip = ftrace_get_ool_stub(rec) + MCOUNT_INSN_SIZE; /* second instruction in stub */
                ret = ftrace_get_call_inst(rec, (unsigned long)ftrace_caller, &old);
        }

        ret |= ftrace_get_call_inst(rec, addr, &new);

        if (!ret)
                ret = ftrace_modify_code(ip, old, new);

        ret = ftrace_rec_update_ops(rec);
        if (ret)
                return ret;

        if (!ret && IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE))
                ret = ftrace_modify_code(rec->ip, ppc_inst(PPC_RAW_NOP()),
                         ppc_inst(PPC_RAW_BRANCH((long)ftrace_get_ool_stub(rec) - (long)rec->ip)));

        return ret;
}

int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr)
{
        /*
         * This should never be called since we override ftrace_replace_code(),
         * as well as ftrace_init_nop()
         */
        WARN_ON(1);
        return -EINVAL;
}

void ftrace_replace_code(int enable)
{
        ppc_inst_t old, new, call_inst, new_call_inst;
        ppc_inst_t nop_inst = ppc_inst(PPC_RAW_NOP());
        unsigned long ip, new_addr, addr;
        struct ftrace_rec_iter *iter;
        struct dyn_ftrace *rec;
        int ret = 0, update;

        for_ftrace_rec_iter(iter) {
                rec = ftrace_rec_iter_record(iter);
                ip = rec->ip;

                if (rec->flags & FTRACE_FL_DISABLED && !(rec->flags & FTRACE_FL_ENABLED))
                        continue;

                addr = ftrace_get_addr_curr(rec);
                new_addr = ftrace_get_addr_new(rec);
                update = ftrace_update_record(rec, enable);

                if (IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE) && update != FTRACE_UPDATE_IGNORE) {
                        ip = ftrace_get_ool_stub(rec) + MCOUNT_INSN_SIZE;
                        ret = ftrace_get_call_inst(rec, (unsigned long)ftrace_caller, &nop_inst);
                        if (ret)
                                goto out;
                }

                switch (update) {
                case FTRACE_UPDATE_IGNORE:
                default:
                        continue;
                case FTRACE_UPDATE_MODIFY_CALL:
                        ret = ftrace_get_call_inst(rec, new_addr, &new_call_inst);
                        ret |= ftrace_get_call_inst(rec, addr, &call_inst);
                        ret |= ftrace_rec_update_ops(rec);
                        old = call_inst;
                        new = new_call_inst;
                        break;
                case FTRACE_UPDATE_MAKE_NOP:
                        ret = ftrace_get_call_inst(rec, addr, &call_inst);
                        ret |= ftrace_rec_set_nop_ops(rec);
                        old = call_inst;
                        new = nop_inst;
                        break;
                case FTRACE_UPDATE_MAKE_CALL:
                        ret = ftrace_get_call_inst(rec, new_addr, &call_inst);
                        ret |= ftrace_rec_update_ops(rec);
                        old = nop_inst;
                        new = call_inst;
                        break;
                }

                if (!ret)
                        ret = ftrace_modify_code(ip, old, new);

                if (!ret && IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE) &&
                    (update == FTRACE_UPDATE_MAKE_NOP || update == FTRACE_UPDATE_MAKE_CALL)) {
                        /* Update the actual ftrace location */
                        call_inst = ppc_inst(PPC_RAW_BRANCH((long)ftrace_get_ool_stub(rec) -
                                                            (long)rec->ip));
                        nop_inst = ppc_inst(PPC_RAW_NOP());
                        ip = rec->ip;

                        if (update == FTRACE_UPDATE_MAKE_NOP)
                                ret = ftrace_modify_code(ip, call_inst, nop_inst);
                        else
                                ret = ftrace_modify_code(ip, nop_inst, call_inst);

                        if (ret)
                                goto out;
                }

                if (ret)
                        goto out;
        }

out:
        if (ret)
                ftrace_bug(ret, rec);
        return;
}

int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec)
{
        unsigned long addr, ip = rec->ip;
        ppc_inst_t old, new;
        int ret = 0;

        /* Verify instructions surrounding the ftrace location */
        if (IS_ENABLED(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY)) {
                /* Expect nops */
                if (!IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE))
                        ret = ftrace_validate_inst(ip - 4, ppc_inst(PPC_RAW_NOP()));
                if (!ret)
                        ret = ftrace_validate_inst(ip, ppc_inst(PPC_RAW_NOP()));
        } else if (IS_ENABLED(CONFIG_PPC32)) {
                /* Expected sequence: 'mflr r0', 'stw r0,4(r1)', 'bl _mcount' */
                ret = ftrace_validate_inst(ip - 8, ppc_inst(PPC_RAW_MFLR(_R0)));
                if (ret)
                        return ret;
                ret = ftrace_modify_code(ip - 4, ppc_inst(PPC_RAW_STW(_R0, _R1, 4)),
                                         ppc_inst(PPC_RAW_NOP()));
        } else if (IS_ENABLED(CONFIG_MPROFILE_KERNEL)) {
                /* Expected sequence: 'mflr r0', ['std r0,16(r1)'], 'bl _mcount' */
                ret = ftrace_read_inst(ip - 4, &old);
                if (!ret && !ppc_inst_equal(old, ppc_inst(PPC_RAW_MFLR(_R0)))) {
                        /* Gcc v5.x emit the additional 'std' instruction, gcc v6.x don't */
                        ret = ftrace_validate_inst(ip - 8, ppc_inst(PPC_RAW_MFLR(_R0)));
                        if (ret)
                                return ret;
                        ret = ftrace_modify_code(ip - 4, ppc_inst(PPC_RAW_STD(_R0, _R1, 16)),
                                                 ppc_inst(PPC_RAW_NOP()));
                }
        } else {
                return -EINVAL;
        }

        if (ret)
                return ret;

        /* Set up out-of-line stub */
        if (IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE)) {
                ret = ftrace_init_ool_stub(mod, rec);
                goto out;
        }

        /* Nop-out the ftrace location */
        new = ppc_inst(PPC_RAW_NOP());
        addr = MCOUNT_ADDR;
        if (IS_ENABLED(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY)) {
                /* we instead patch-in the 'mflr r0' */
                old = ppc_inst(PPC_RAW_NOP());
                new = ppc_inst(PPC_RAW_MFLR(_R0));
                ret = ftrace_modify_code(ip - 4, old, new);
        } else if (is_offset_in_branch_range(addr - ip)) {
                /* Within range */
                old = ftrace_create_branch_inst(ip, addr, 1);
                ret = ftrace_modify_code(ip, old, new);
        } else if (core_kernel_text(ip) || (IS_ENABLED(CONFIG_MODULES) && mod)) {
                /*
                 * We would be branching to a linker-generated stub, or to the module _mcount
                 * stub. Let's just confirm we have a 'bl' here.
                 */
                ret = ftrace_read_inst(ip, &old);
                if (ret)
                        return ret;
                if (!is_bl_op(old)) {
                        pr_err("0x%lx: expected (bl) != found (%08lx)\n", ip, ppc_inst_as_ulong(old));
                        return -EINVAL;
                }
                ret = patch_instruction((u32 *)ip, new);
        } else {
                return -EINVAL;
        }

out:
        if (!ret)
                ret = ftrace_rec_set_nop_ops(rec);

        return ret;
}

int ftrace_update_ftrace_func(ftrace_func_t func)
{
        unsigned long ip = (unsigned long)(&ftrace_call);
        ppc_inst_t old, new;
        int ret;

        /*
         * When using CALL_OPS, the function to call is associated with the
         * call site, and we don't have a global function pointer to update.
         */
        if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS))
                return 0;

        old = ppc_inst_read((u32 *)&ftrace_call);
        new = ftrace_create_branch_inst(ip, ppc_function_entry(func), 1);
        ret = ftrace_modify_code(ip, old, new);

        /* Also update the regs callback function */
        if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && !ret) {
                ip = (unsigned long)(&ftrace_regs_call);
                old = ppc_inst_read((u32 *)&ftrace_regs_call);
                new = ftrace_create_branch_inst(ip, ppc_function_entry(func), 1);
                ret = ftrace_modify_code(ip, old, new);
        }

        return ret;
}

/*
 * Use the default ftrace_modify_all_code, but without
 * stop_machine().
 */
void arch_ftrace_update_code(int command)
{
        ftrace_modify_all_code(command);
}

void ftrace_free_init_tramp(void)
{
        int i;

        for (i = 0; i < NUM_FTRACE_TRAMPS && ftrace_tramps[i]; i++)
                if (ftrace_tramps[i] == (unsigned long)ftrace_tramp_init) {
                        ftrace_tramps[i] = 0;
                        return;
                }
}

static void __init add_ftrace_tramp(unsigned long tramp)
{
        int i;

        for (i = 0; i < NUM_FTRACE_TRAMPS; i++)
                if (!ftrace_tramps[i]) {
                        ftrace_tramps[i] = tramp;
                        return;
                }
}

int __init ftrace_dyn_arch_init(void)
{
        unsigned int *tramp[] = { ftrace_tramp_text, ftrace_tramp_init };
        unsigned long addr = FTRACE_REGS_ADDR;
        long reladdr;
        int i;
        u32 stub_insns[] = {
#ifdef CONFIG_PPC_KERNEL_PCREL
                /* pla r12,addr */
                PPC_PREFIX_MLS | __PPC_PRFX_R(1),
                PPC_INST_PADDI | ___PPC_RT(_R12),
                PPC_RAW_MTCTR(_R12),
                PPC_RAW_BCTR()
#elif defined(CONFIG_PPC64)
                PPC_RAW_LD(_R12, _R13, offsetof(struct paca_struct, kernel_toc)),
                PPC_RAW_ADDIS(_R12, _R12, 0),
                PPC_RAW_ADDI(_R12, _R12, 0),
                PPC_RAW_MTCTR(_R12),
                PPC_RAW_BCTR()
#else
                PPC_RAW_LIS(_R12, 0),
                PPC_RAW_ADDI(_R12, _R12, 0),
                PPC_RAW_MTCTR(_R12),
                PPC_RAW_BCTR()
#endif
        };

        if (IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) {
                for (i = 0; i < 2; i++) {
                        reladdr = addr - (unsigned long)tramp[i];

                        if (reladdr >= (long)SZ_8G || reladdr < -(long)SZ_8G) {
                                pr_err("Address of %ps out of range of pcrel address.\n",
                                        (void *)addr);
                                return -1;
                        }

                        memcpy(tramp[i], stub_insns, sizeof(stub_insns));
                        tramp[i][0] |= IMM_H18(reladdr);
                        tramp[i][1] |= IMM_L(reladdr);
                        add_ftrace_tramp((unsigned long)tramp[i]);
                }
        } else if (IS_ENABLED(CONFIG_PPC64)) {
                reladdr = addr - kernel_toc_addr();

                if (reladdr >= (long)SZ_2G || reladdr < -(long long)SZ_2G) {
                        pr_err("Address of %ps out of range of kernel_toc.\n",
                                (void *)addr);
                        return -1;
                }

                for (i = 0; i < 2; i++) {
                        memcpy(tramp[i], stub_insns, sizeof(stub_insns));
                        tramp[i][1] |= PPC_HA(reladdr);
                        tramp[i][2] |= PPC_LO(reladdr);
                        add_ftrace_tramp((unsigned long)tramp[i]);
                }
        } else {
                for (i = 0; i < 2; i++) {
                        memcpy(tramp[i], stub_insns, sizeof(stub_insns));
                        tramp[i][0] |= PPC_HA(addr);
                        tramp[i][1] |= PPC_LO(addr);
                        add_ftrace_tramp((unsigned long)tramp[i]);
                }
        }

        return 0;
}

#ifdef CONFIG_FUNCTION_GRAPH_TRACER
void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
                       struct ftrace_ops *op, struct ftrace_regs *fregs)
{
        unsigned long sp = arch_ftrace_regs(fregs)->regs.gpr[1];

        if (unlikely(ftrace_graph_is_dead()))
                goto out;

        if (unlikely(atomic_read(&current->tracing_graph_pause)))
                goto out;

        if (!function_graph_enter_regs(parent_ip, ip, 0, (unsigned long *)sp, fregs))
                parent_ip = ppc_function_entry(return_to_handler);

out:
        arch_ftrace_regs(fregs)->regs.link = parent_ip;
}
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */