/*-
 * Copyright (c) 2014-2015 The FreeBSD Foundation
 *
 * Portions of this software were developed by Andrew Turner
 * under sponsorship from the FreeBSD Foundation.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/types.h>

#include <machine/sysarch.h>

#include <stdlib.h>

#include "debug.h"
#include "rtld.h"
#include "rtld_printf.h"

/*
 * This is not the correct prototype, but we only need it for
 * a function pointer to a simple asm function.
 */
void *_rtld_tlsdesc_static(void *);
void *_rtld_tlsdesc_undef(void *);
void *_rtld_tlsdesc_dynamic(void *);

bool
arch_digest_dynamic(struct Struct_Obj_Entry *obj, const Elf_Dyn *dynp)
{
        if (dynp->d_tag == DT_AARCH64_VARIANT_PCS) {
                obj->variant_pcs = true;
                return (true);
        }

        return (false);
}

bool
arch_digest_note(struct Struct_Obj_Entry *obj __unused, const Elf_Note *note)
{
        const char *note_name;
        const uint32_t *note_data;

        note_name = (const char *)(note + 1);
        /* Only handle GNU notes */
        if (note->n_namesz != sizeof(ELF_NOTE_GNU) ||
            strncmp(note_name, ELF_NOTE_GNU, sizeof(ELF_NOTE_GNU)) != 0)
                return (false);

        /* Only handle GNU property notes */
        if (note->n_type != NT_GNU_PROPERTY_TYPE_0)
                return (false);

        /*
         * note_data[0] - Type
         * note_data[1] - Length
         * note_data[2] - Data
         * note_data[3] - Padding?
         */
        note_data = (const uint32_t *)(note_name + note->n_namesz);

        /* Only handle AArch64 feature notes */
        if (note_data[0] != GNU_PROPERTY_AARCH64_FEATURE_1_AND)
                return (false);

        /* We expect at least 4 bytes of data */
        if (note_data[1] < 4)
                return (false);

        /* TODO: Only guard if HWCAP2_BTI is set */
        if ((note_data[2] & GNU_PROPERTY_AARCH64_FEATURE_1_BTI) != 0) {
                struct arm64_guard_page_args guard;

                guard.addr = (uintptr_t)obj->mapbase;
                guard.len = obj->mapsize;

                sysarch(ARM64_GUARD_PAGE, &guard);
        }

        return (true);
}

void
init_pltgot(Obj_Entry *obj)
{

        if (obj->pltgot != NULL) {
                obj->pltgot[1] = (Elf_Addr) obj;
                obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start;
        }
}

int
do_copy_relocations(Obj_Entry *dstobj)
{
        const Obj_Entry *srcobj, *defobj;
        const Elf_Rela *relalim;
        const Elf_Rela *rela;
        const Elf_Sym *srcsym;
        const Elf_Sym *dstsym;
        const void *srcaddr;
        const char *name;
        void *dstaddr;
        SymLook req;
        size_t size;
        int res;

        /*
         * COPY relocs are invalid outside of the main program
         */
        assert(dstobj->mainprog);

        relalim = (const Elf_Rela *)((const char *)dstobj->rela +
            dstobj->relasize);
        for (rela = dstobj->rela; rela < relalim; rela++) {
                if (ELF_R_TYPE(rela->r_info) != R_AARCH64_COPY)
                        continue;

                dstaddr = (void *)(dstobj->relocbase + rela->r_offset);
                dstsym = dstobj->symtab + ELF_R_SYM(rela->r_info);
                name = dstobj->strtab + dstsym->st_name;
                size = dstsym->st_size;

                symlook_init(&req, name);
                req.ventry = fetch_ventry(dstobj, ELF_R_SYM(rela->r_info));
                req.flags = SYMLOOK_EARLY;

                for (srcobj = globallist_next(dstobj); srcobj != NULL;
                     srcobj = globallist_next(srcobj)) {
                        res = symlook_obj(&req, srcobj);
                        if (res == 0) {
                                srcsym = req.sym_out;
                                defobj = req.defobj_out;
                                break;
                        }
                }
                if (srcobj == NULL) {
                        _rtld_error("Undefined symbol \"%s\" referenced from "
                            "COPY relocation in %s", name, dstobj->path);
                        return (-1);
                }

                srcaddr = (const void *)(defobj->relocbase + srcsym->st_value);
                memcpy(dstaddr, srcaddr, size);
        }

        return (0);
}

struct tls_data {
        Elf_Addr        dtv_gen;
        int             tls_index;
        Elf_Addr        tls_offs;
};

static struct tls_data *
reloc_tlsdesc_alloc(int tlsindex, Elf_Addr tlsoffs)
{
        struct tls_data *tlsdesc;

        tlsdesc = xmalloc(sizeof(struct tls_data));
        tlsdesc->dtv_gen = tls_dtv_generation;
        tlsdesc->tls_index = tlsindex;
        tlsdesc->tls_offs = tlsoffs;

        return (tlsdesc);
}

struct tlsdesc_entry {
        void    *(*func)(void *);
        union {
                Elf_Ssize       addend;
                Elf_Size        offset;
                struct tls_data *data;
        };
};

static void
reloc_tlsdesc(const Obj_Entry *obj, const Elf_Rela *rela,
    struct tlsdesc_entry *where, int flags, RtldLockState *lockstate)
{
        const Elf_Sym *def;
        const Obj_Entry *defobj;
        Elf_Addr offs;

        offs = 0;
        if (ELF_R_SYM(rela->r_info) != 0) {
                def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, flags,
                            NULL, lockstate);
                if (def == NULL)
                        rtld_die();
                offs = def->st_value;
                obj = defobj;
                if (def->st_shndx == SHN_UNDEF) {
                        /* Weak undefined thread variable */
                        where->func = _rtld_tlsdesc_undef;
                        where->addend = rela->r_addend;
                        return;
                }
        }
        offs += rela->r_addend;

        if (obj->tlsoffset != 0) {
                /* Variable is in initialy allocated TLS segment */
                where->func = _rtld_tlsdesc_static;
                where->offset = obj->tlsoffset + offs;
        } else {
                /* TLS offest is unknown at load time, use dynamic resolving */
                where->func = _rtld_tlsdesc_dynamic;
                where->data = reloc_tlsdesc_alloc(obj->tlsindex, offs);
        }
}

/*
 * Process the PLT relocations.
 */
int
reloc_plt(Obj_Entry *obj, int flags, RtldLockState *lockstate)
{
        const Obj_Entry *defobj;
        const Elf_Rela *relalim;
        const Elf_Rela *rela;
        const Elf_Sym *def, *sym;
        bool lazy;

        relalim = (const Elf_Rela *)((const char *)obj->pltrela +
            obj->pltrelasize);
        for (rela = obj->pltrela; rela < relalim; rela++) {
                Elf_Addr *where, target;

                where = (Elf_Addr *)(obj->relocbase + rela->r_offset);

                switch(ELF_R_TYPE(rela->r_info)) {
                case R_AARCH64_JUMP_SLOT:
                        lazy = true;
                        if (obj->variant_pcs) {
                                sym = &obj->symtab[ELF_R_SYM(rela->r_info)];
                                /*
                                 * Variant PCS functions don't follow the
                                 * standard register convention. Because of
                                 * this we can't use lazy relocation and
                                 * need to set the target address.
                                 */
                                if ((sym->st_other & STO_AARCH64_VARIANT_PCS) !=
                                    0)
                                        lazy = false;
                        }
                        if (lazy) {
                                *where += (Elf_Addr)obj->relocbase;
                        } else {
                                def = find_symdef(ELF_R_SYM(rela->r_info), obj,
                                    &defobj, SYMLOOK_IN_PLT | flags, NULL,
                                    lockstate);
                                if (def == NULL)
                                        return (-1);
                                if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC){
                                        obj->gnu_ifunc = true;
                                        continue;
                                }
                                target = (Elf_Addr)(defobj->relocbase +
                                    def->st_value);
                                /*
                                 * Ignore ld_bind_not as it requires lazy
                                 * binding
                                 */
                                *where = target;
                        }
                        break;
                case R_AARCH64_TLSDESC:
                        reloc_tlsdesc(obj, rela, (struct tlsdesc_entry *)where,
                            SYMLOOK_IN_PLT | flags, lockstate);
                        break;
                case R_AARCH64_IRELATIVE:
                        obj->irelative = true;
                        break;
                case R_AARCH64_NONE:
                        break;
                default:
                        _rtld_error("Unknown relocation type %u in PLT",
                            (unsigned int)ELF_R_TYPE(rela->r_info));
                        return (-1);
                }
        }

        return (0);
}

/*
 * LD_BIND_NOW was set - force relocation for all jump slots
 */
int
reloc_jmpslots(Obj_Entry *obj, int flags, RtldLockState *lockstate)
{
        const Obj_Entry *defobj;
        const Elf_Rela *relalim;
        const Elf_Rela *rela;
        const Elf_Sym *def;

        if (obj->jmpslots_done)
                return (0);

        relalim = (const Elf_Rela *)((const char *)obj->pltrela +
            obj->pltrelasize);
        for (rela = obj->pltrela; rela < relalim; rela++) {
                Elf_Addr *where, target;

                where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
                switch(ELF_R_TYPE(rela->r_info)) {
                case R_AARCH64_JUMP_SLOT:
                        def = find_symdef(ELF_R_SYM(rela->r_info), obj,
                            &defobj, SYMLOOK_IN_PLT | flags, NULL, lockstate);
                        if (def == NULL)
                                return (-1);
                        if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) {
                                obj->gnu_ifunc = true;
                                continue;
                        }
                        target = (Elf_Addr)(defobj->relocbase + def->st_value);
                        reloc_jmpslot(where, target, defobj, obj,
                            (const Elf_Rel *)rela);
                        break;
                }
        }
        obj->jmpslots_done = true;

        return (0);
}

static void
reloc_iresolve_one(Obj_Entry *obj, const Elf_Rela *rela,
    RtldLockState *lockstate)
{
        Elf_Addr *where, target, *ptr;

        ptr = (Elf_Addr *)(obj->relocbase + rela->r_addend);
        where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
        lock_release(rtld_bind_lock, lockstate);
        target = call_ifunc_resolver(ptr);
        wlock_acquire(rtld_bind_lock, lockstate);
        *where = target;
}

int
reloc_iresolve(Obj_Entry *obj, struct Struct_RtldLockState *lockstate)
{
        const Elf_Rela *relalim;
        const Elf_Rela *rela;

        if (!obj->irelative)
                return (0);
        obj->irelative = false;
        relalim = (const Elf_Rela *)((const char *)obj->pltrela +
            obj->pltrelasize);
        for (rela = obj->pltrela;  rela < relalim;  rela++) {
                if (ELF_R_TYPE(rela->r_info) == R_AARCH64_IRELATIVE)
                        reloc_iresolve_one(obj, rela, lockstate);
        }
        return (0);
}

int
reloc_iresolve_nonplt(Obj_Entry *obj, struct Struct_RtldLockState *lockstate)
{
        const Elf_Rela *relalim;
        const Elf_Rela *rela;

        if (!obj->irelative_nonplt)
                return (0);
        obj->irelative_nonplt = false;
        relalim = (const Elf_Rela *)((const char *)obj->rela + obj->relasize);
        for (rela = obj->rela;  rela < relalim;  rela++) {
                if (ELF_R_TYPE(rela->r_info) == R_AARCH64_IRELATIVE)
                        reloc_iresolve_one(obj, rela, lockstate);
        }
        return (0);
}

int
reloc_gnu_ifunc(Obj_Entry *obj, int flags,
   struct Struct_RtldLockState *lockstate)
{
        const Elf_Rela *relalim;
        const Elf_Rela *rela;
        Elf_Addr *where, target;
        const Elf_Sym *def;
        const Obj_Entry *defobj;

        if (!obj->gnu_ifunc)
                return (0);
        relalim = (const Elf_Rela *)((const char *)obj->pltrela + obj->pltrelasize);
        for (rela = obj->pltrela;  rela < relalim;  rela++) {
                if (ELF_R_TYPE(rela->r_info) == R_AARCH64_JUMP_SLOT) {
                        where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
                        def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj,
                            SYMLOOK_IN_PLT | flags, NULL, lockstate);
                        if (def == NULL)
                                return (-1);
                        if (ELF_ST_TYPE(def->st_info) != STT_GNU_IFUNC)
                                continue;
                        lock_release(rtld_bind_lock, lockstate);
                        target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
                        wlock_acquire(rtld_bind_lock, lockstate);
                        reloc_jmpslot(where, target, defobj, obj,
                            (const Elf_Rel *)rela);
                }
        }
        obj->gnu_ifunc = false;
        return (0);
}

Elf_Addr
reloc_jmpslot(Elf_Addr *where, Elf_Addr target,
    const Obj_Entry *defobj __unused, const Obj_Entry *obj __unused,
    const Elf_Rel *rel)
{

        assert(ELF_R_TYPE(rel->r_info) == R_AARCH64_JUMP_SLOT ||
            ELF_R_TYPE(rel->r_info) == R_AARCH64_IRELATIVE);

        if (*where != target && !ld_bind_not)
                *where = target;
        return (target);
}

__ifunc_arg_t ifunc_arg = {
        ._size = sizeof(__ifunc_arg_t)
};

void
ifunc_init(Elf_Auxinfo *aux_info[__min_size(AT_COUNT)])
{
        ifunc_arg._hwcap = aux_info[AT_HWCAP] != NULL ?
            (aux_info[AT_HWCAP]->a_un.a_val | _IFUNC_ARG_HWCAP) : 0;
        ifunc_arg._hwcap2 = aux_info[AT_HWCAP2] != NULL ?
            aux_info[AT_HWCAP2]->a_un.a_val : 0;
        ifunc_arg._hwcap3 = aux_info[AT_HWCAP3] != NULL ?
            aux_info[AT_HWCAP3]->a_un.a_val : 0;
        ifunc_arg._hwcap4 = aux_info[AT_HWCAP4] != NULL ?
            aux_info[AT_HWCAP4]->a_un.a_val : 0;
}

/*
 * Process non-PLT relocations
 */
int
reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld, int flags,
    RtldLockState *lockstate)
{
        const Obj_Entry *defobj;
        const Elf_Rela *relalim;
        const Elf_Rela *rela;
        const Elf_Sym *def;
        SymCache *cache;
        Elf_Addr *where, symval;

        /*
         * The dynamic loader may be called from a thread, we have
         * limited amounts of stack available so we cannot use alloca().
         */
        if (obj == obj_rtld)
                cache = NULL;
        else
                cache = calloc(obj->dynsymcount, sizeof(SymCache));
                /* No need to check for NULL here */

        relalim = (const Elf_Rela *)((const char *)obj->rela + obj->relasize);
        for (rela = obj->rela; rela < relalim; rela++) {
                /*
                 * First, resolve symbol for relocations which
                 * reference symbols.
                 */
                switch (ELF_R_TYPE(rela->r_info)) {
                case R_AARCH64_ABS64:
                case R_AARCH64_GLOB_DAT:
                case R_AARCH64_TLS_TPREL64:
                case R_AARCH64_TLS_DTPREL64:
                case R_AARCH64_TLS_DTPMOD64:
                        def = find_symdef(ELF_R_SYM(rela->r_info), obj,
                            &defobj, flags, cache, lockstate);
                        if (def == NULL)
                                return (-1);
                        /*
                         * If symbol is IFUNC, only perform relocation
                         * when caller allowed it by passing
                         * SYMLOOK_IFUNC flag.  Skip the relocations
                         * otherwise.
                         *
                         * Also error out in case IFUNC relocations
                         * are specified for TLS, which cannot be
                         * usefully interpreted.
                         */
                        if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) {
                                switch (ELF_R_TYPE(rela->r_info)) {
                                case R_AARCH64_ABS64:
                                case R_AARCH64_GLOB_DAT:
                                        if ((flags & SYMLOOK_IFUNC) == 0) {
                                                obj->non_plt_gnu_ifunc = true;
                                                continue;
                                        }
                                        symval = (Elf_Addr)rtld_resolve_ifunc(
                                            defobj, def);
                                        break;
                                default:
                                        _rtld_error("%s: IFUNC for TLS reloc",
                                            obj->path);
                                        return (-1);
                                }
                        } else {
                                if ((flags & SYMLOOK_IFUNC) != 0)
                                        continue;
                                symval = (Elf_Addr)defobj->relocbase +
                                    def->st_value;
                        }
                        break;
                default:
                        if ((flags & SYMLOOK_IFUNC) != 0)
                                continue;
                }

                where = (Elf_Addr *)(obj->relocbase + rela->r_offset);

                switch (ELF_R_TYPE(rela->r_info)) {
                case R_AARCH64_ABS64:
                case R_AARCH64_GLOB_DAT:
                        *where = symval + rela->r_addend;
                        break;
                case R_AARCH64_COPY:
                        /*
                         * These are deferred until all other relocations have
                         * been done. All we do here is make sure that the
                         * COPY relocation is not in a shared library. They
                         * are allowed only in executable files.
                         */
                        if (!obj->mainprog) {
                                _rtld_error("%s: Unexpected R_AARCH64_COPY "
                                    "relocation in shared library", obj->path);
                                return (-1);
                        }
                        break;
                case R_AARCH64_TLSDESC:
                        reloc_tlsdesc(obj, rela, (struct tlsdesc_entry *)where,
                            flags, lockstate);
                        break;
                case R_AARCH64_TLS_TPREL64:
                        /*
                         * We lazily allocate offsets for static TLS as we
                         * see the first relocation that references the
                         * TLS block. This allows us to support (small
                         * amounts of) static TLS in dynamically loaded
                         * modules. If we run out of space, we generate an
                         * error.
                         */
                        if (!defobj->tls_static) {
                                if (!allocate_tls_offset(
                                    __DECONST(Obj_Entry *, defobj))) {
                                        _rtld_error(
                                            "%s: No space available for static "
                                            "Thread Local Storage", obj->path);
                                        return (-1);
                                }
                        }
                        *where = def->st_value + rela->r_addend +
                            defobj->tlsoffset;
                        break;

                /*
                 * !!! BEWARE !!!
                 * ARM ELF ABI defines TLS_DTPMOD64 as 1029, and TLS_DTPREL64
                 * as 1028. But actual bfd linker and the glibc RTLD linker
                 * treats TLS_DTPMOD64 as 1028 and TLS_DTPREL64 1029.
                 */
                case R_AARCH64_TLS_DTPREL64: /* efectively is TLS_DTPMOD64 */
                        *where += (Elf_Addr)defobj->tlsindex;
                        break;
                case R_AARCH64_TLS_DTPMOD64: /* efectively is TLS_DTPREL64 */
                        *where += (Elf_Addr)(def->st_value + rela->r_addend);
                        break;
                case R_AARCH64_RELATIVE:
                        *where = (Elf_Addr)(obj->relocbase + rela->r_addend);
                        break;
                case R_AARCH64_NONE:
                        break;
                case R_AARCH64_IRELATIVE:
                        obj->irelative_nonplt = true;
                        break;
                default:
                        rtld_printf("%s: Unhandled relocation %lu\n",
                            obj->path, ELF_R_TYPE(rela->r_info));
                        return (-1);
                }
        }

        return (0);
}

void
allocate_initial_tls(Obj_Entry *objs)
{

        /*
        * Fix the size of the static TLS block by using the maximum
        * offset allocated so far and adding a bit for dynamic modules to
        * use.
        */
        tls_static_space = tls_last_offset + tls_last_size +
            ld_static_tls_extra;

        _tcb_set(allocate_tls(objs, NULL, TLS_TCB_SIZE, TLS_TCB_ALIGN));
}

void *
__tls_get_addr(tls_index* ti)
{
        return (tls_get_addr_common(_tcb_get(), ti->ti_module, ti->ti_offset));
}