/*      $NetBSD: ppc_reloc.c,v 1.10 2001/09/10 06:09:41 mycroft Exp $   */

/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (C) 1998   Tsubai Masanari
 * All rights reserved.
 *
 * 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.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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/param.h>
#include <sys/mman.h>

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <machine/cpu.h>
#include <machine/atomic.h>
#include <machine/md_var.h>

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

#define _ppc_ha(x) ((((u_int32_t)(x) & 0x8000) ? \
                        ((u_int32_t)(x) + 0x10000) : (u_int32_t)(x)) >> 16)
#define _ppc_la(x) ((u_int32_t)(x) & 0xffff)

#define min(a,b) (((a) < (b)) ? (a) : (b))
#define max(a,b) (((a) > (b)) ? (a) : (b))

#define PLT_EXTENDED_BEGIN      (1 << 13)
#define JMPTAB_BASE(N)          (18 + N*2 + ((N > PLT_EXTENDED_BEGIN) ? \
                                    (N - PLT_EXTENDED_BEGIN)*2 : 0))

void _rtld_bind_secureplt_start(void);

bool
arch_digest_dynamic(struct Struct_Obj_Entry *obj, const Elf_Dyn *dynp)
{
        if (dynp->d_tag == DT_PPC_GOT) {
                obj->gotptr = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr);
                return (true);
        }

        return (false);
}

/*
 * Process the R_PPC_COPY relocations
 */
int
do_copy_relocations(Obj_Entry *dstobj)
{
        const Elf_Rela *relalim;
        const Elf_Rela *rela;

        /*
         * 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++) {
                void *dstaddr;
                const Elf_Sym *dstsym;
                const char *name;
                size_t size;
                const void *srcaddr;
                const Elf_Sym *srcsym = NULL;
                const Obj_Entry *srcobj, *defobj;
                SymLook req;
                int res;

                if (ELF_R_TYPE(rela->r_info) != R_PPC_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);
                dbg("copy_reloc: src=%p,dst=%p,size=%d\n",srcaddr,dstaddr,size);
        }

        return (0);
}


/*
 * Perform early relocation of the run-time linker image
 */
void
reloc_non_plt_self(Elf_Dyn *dynp, Elf_Addr relocbase)
{
        const Elf_Rela *rela = NULL, *relalim;
        Elf_Addr relasz = 0;
        Elf_Addr *where;

        /*
         * Extract the rela/relasz values from the dynamic section
         */
        for (; dynp->d_tag != DT_NULL; dynp++) {
                switch (dynp->d_tag) {
                case DT_RELA:
                        rela = (const Elf_Rela *)(relocbase+dynp->d_un.d_ptr);
                        break;
                case DT_RELASZ:
                        relasz = dynp->d_un.d_val;
                        break;
                }
        }

        /*
         * Relocate these values
         */
        relalim = (const Elf_Rela *)((const char *)rela + relasz);
        for (; rela < relalim; rela++) {
                where = (Elf_Addr *)(relocbase + rela->r_offset);
                *where = (Elf_Addr)(relocbase + rela->r_addend);
        }
}


/*
 * Relocate a non-PLT object with addend.
 */
static int
reloc_nonplt_object(Obj_Entry *obj_rtld __unused, Obj_Entry *obj,
    const Elf_Rela *rela, SymCache *cache, int flags, RtldLockState *lockstate)
{
        const Elf_Sym   *def = NULL;
        const Obj_Entry *defobj;
        Elf_Addr        *where, symval = 0;

        /*
         * First, resolve symbol for relocations which
         * reference symbols.
         */
        switch (ELF_R_TYPE(rela->r_info)) {

        case R_PPC_UADDR32:    /* word32 S + A */
        case R_PPC_ADDR32:
        case R_PPC_GLOB_DAT:  /* word32 S + A */
        case R_PPC_DTPMOD32:
        case R_PPC_TPREL32:
        case R_PPC_DTPREL32:
                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_PPC_UADDR32:
                        case R_PPC_ADDR32:
                        case R_PPC_GLOB_DAT:
                                if ((flags & SYMLOOK_IFUNC) == 0) {
                                        dbg("Non-PLT reference to IFUNC found!");
                                        obj->non_plt_gnu_ifunc = true;
                                        return (0);
                                }
                                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)
                                return (0);
                        symval = (Elf_Addr)defobj->relocbase +
                                def->st_value;
                }
                break;
        default:
                if ((flags & SYMLOOK_IFUNC) != 0)
                        return (0);
        }
        where = (Elf_Addr *)(obj->relocbase + rela->r_offset);

        switch (ELF_R_TYPE(rela->r_info)) {
        case R_PPC_NONE:
                break;
        case R_PPC_UADDR32:
        case R_PPC_ADDR32:
        case R_PPC_GLOB_DAT:
                /* Don't issue write if unnecessary; avoid COW page fault */
                if (*where != symval + rela->r_addend) {
                        *where = symval + rela->r_addend;
                }
                break;
        case R_PPC_DTPMOD32:
                *where = (Elf_Addr) defobj->tlsindex;
                break;
        case R_PPC_TPREL32:
                /*
                 * 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);
                        }
                }

                *(Elf_Addr **)where = *where * sizeof(Elf_Addr)
                    + (Elf_Addr *)(def->st_value + rela->r_addend 
                    + defobj->tlsoffset - TLS_TP_OFFSET - TLS_TCB_SIZE);
                break;
        case R_PPC_DTPREL32:
                *where += (Elf_Addr)(def->st_value + rela->r_addend 
                    - TLS_DTV_OFFSET);
                break;
        case R_PPC_RELATIVE: /* word32 B + A */
                symval = (Elf_Addr)(obj->relocbase + rela->r_addend);

                /* As above, don't issue write unnecessarily */
                if (*where != symval) {
                        *where = symval;
                }
                break;
        case R_PPC_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_COPY "
                                    " relocation in shared library",
                                    obj->path);
                        return (-1);
                }
                break;
        case R_PPC_IRELATIVE:
                /*
                 * These will be handled by reloc_iresolve().
                 */
                obj->irelative = true;
                break;
        case R_PPC_JMP_SLOT:
                /*
                 * These will be handled by the plt/jmpslot routines
                 */
                break;

        default:
                _rtld_error("%s: Unsupported relocation type %d"
                            " in non-PLT relocations\n", obj->path,
                            ELF_R_TYPE(rela->r_info));
                return (-1);
        }
        return (0);
}


/*
 * Process non-PLT relocations
 */
int
reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld, int flags,
    RtldLockState *lockstate)
{
        const Elf_Rela *relalim;
        const Elf_Rela *rela;
        SymCache *cache;
        int r = -1;

        /*
         * 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 = calloc(obj->dynsymcount, sizeof(SymCache));
                /* No need to check for NULL here */
        } else
                cache = NULL;

        /*
         * From the SVR4 PPC ABI:
         * "The PowerPC family uses only the Elf32_Rela relocation
         *  entries with explicit addends."
         */
        relalim = (const Elf_Rela *)((const char *)obj->rela + obj->relasize);
        for (rela = obj->rela; rela < relalim; rela++) {
                if (reloc_nonplt_object(obj_rtld, obj, rela, cache, flags,
                    lockstate) < 0)
                        goto done;
        }
        r = 0;
done:
        if (cache != NULL)
                free(cache);
        return (r);
}

/*
 * Initialise a PLT slot to the resolving trampoline
 */
static int
reloc_plt_object(Obj_Entry *obj, const Elf_Rela *rela)
{
        Elf_Word *where = (Elf_Word *)(obj->relocbase + rela->r_offset);
        Elf_Addr *pltresolve, *pltlongresolve, *jmptab;
        Elf_Addr distance;
        int N = obj->pltrelasize / sizeof(Elf_Rela);
        int reloff;

        reloff = rela - obj->pltrela;

        if (reloff < 0)
                return (-1);

        if (obj->gotptr != NULL) {
                *where += (Elf_Addr)obj->relocbase;
                return (0);
        }

        pltlongresolve = obj->pltgot + 5;
        pltresolve = pltlongresolve + 5;

        distance = (Elf_Addr)pltresolve - (Elf_Addr)(where + 1);

        dbg(" reloc_plt_object: where=%p,pltres=%p,reloff=%x,distance=%x",
            (void *)where, (void *)pltresolve, reloff, distance);

        if (reloff < PLT_EXTENDED_BEGIN) {
                /* li   r11,reloff  */
                /* b    pltresolve  */
                where[0] = 0x39600000 | reloff;
                where[1] = 0x48000000 | (distance & 0x03fffffc);
        } else {
                jmptab = obj->pltgot + JMPTAB_BASE(N);
                jmptab[reloff] = (u_int)pltlongresolve;

                /* lis  r11,jmptab[reloff]@ha */
                /* lwzu r12,jmptab[reloff]@l(r11) */
                /* mtctr r12 */
                /* bctr */
                where[0] = 0x3d600000 | _ppc_ha(&jmptab[reloff]);
                where[1] = 0x858b0000 | _ppc_la(&jmptab[reloff]);
                where[2] = 0x7d8903a6;
                where[3] = 0x4e800420;
        }
                

        /*
         * The icache will be sync'd in reloc_plt, which is called
         * after all the slots have been updated
         */

        return (0);
}

/*
 * Process the PLT relocations.
 */
int
reloc_plt(Obj_Entry *obj, int flags __unused, RtldLockState *lockstate __unused)
{
        const Elf_Rela *relalim;
        const Elf_Rela *rela;
        int N = obj->pltrelasize / sizeof(Elf_Rela);

        if (obj->pltrelasize != 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_PPC_IRELATIVE) {
                                dbg("ABI violation - found IRELATIVE in the PLT.");
                                obj->irelative = true;
                                continue;
                        }

                        /*
                         * PowerPC(64) .rela.plt is composed of an array of
                         * R_PPC_JMP_SLOT relocations. Unlike other platforms,
                         * this is the ONLY relocation type that is valid here.
                         */
                        assert(ELF_R_TYPE(rela->r_info) == R_PPC_JMP_SLOT);

                        if (reloc_plt_object(obj, rela) < 0) {
                                return (-1);
                        }
                }
        }

        /*
         * Sync the icache for the byte range represented by the
         * trampoline routines and call slots.
         */
        if (obj->pltgot != NULL && obj->gotptr == NULL)
                __syncicache(obj->pltgot, JMPTAB_BASE(N)*4);

        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;
        Elf_Addr *where;
        Elf_Addr target;

        relalim = (const Elf_Rela *)((const char *)obj->pltrela +
            obj->pltrelasize);
        for (rela = obj->pltrela; rela < relalim; rela++) {
                /* This isn't actually a jump slot, ignore it. */
                if (ELF_R_TYPE(rela->r_info) == R_PPC_IRELATIVE)
                        continue;
                assert(ELF_R_TYPE(rela->r_info) == R_PPC_JMP_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) {
                        dbg("reloc_jmpslots: sym not found");
                        return (-1);
                }

                target = (Elf_Addr)(defobj->relocbase + def->st_value);

                if (def == &sym_zero) {
                        /* Zero undefined weak symbols */
                        *where = 0;
                } else {
                        if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) {
                                /* LD_BIND_NOW, ifunc in shared lib.*/
                                obj->gnu_ifunc = true;
                                continue;
                        }
                        reloc_jmpslot(where, target, defobj, obj,
                            (const Elf_Rel *) rela);
                }
        }

        obj->jmpslots_done = true;

        return (0);
}


/*
 * Update the value of a PLT jump slot.
 */
Elf_Addr
reloc_jmpslot(Elf_Addr *wherep, Elf_Addr target,
    const Obj_Entry *defobj __unused, const Obj_Entry *obj, const Elf_Rel *rel)
{
        Elf_Addr offset;
        const Elf_Rela *rela = (const Elf_Rela *) rel;

        dbg(" reloc_jmpslot: where=%p, target=%p",
            (void *)wherep, (void *)target);

        if (ld_bind_not)
                goto out;


        /*
         * Process Secure-PLT.
         */
        if (obj->gotptr != NULL) {
                assert(wherep >= (Elf_Word *)obj->pltgot);
                assert(wherep <
                    (Elf_Word *)obj->pltgot + obj->pltrelasize);
                if (*wherep != target)
                        *wherep = target;
                goto out;
        }

        /*
         * BSS-PLT optimization:
         * Branch directly to the target if it is within +/- 32Mb,
         * otherwise go indirectly via the pltcall trampoline call and
         * jump table.
         */
        offset = target - (Elf_Addr)wherep;
        if (abs((int)offset) < 32*1024*1024) {     /* inside 32MB? */
                /*
                 * At the PLT entry pointed at by `wherep', construct
                 * a direct transfer to the now fully resolved function
                 * address.
                 */
                /* b    value   # branch directly */
                *wherep = 0x48000000 | (offset & 0x03fffffc);
                __syncicache(wherep, 4);
        } else {
                Elf_Addr *pltcall, *jmptab;
                int distance;
                int N = obj->pltrelasize / sizeof(Elf_Rela);
                int reloff = rela - obj->pltrela;

                if (reloff < 0)
                        return (-1);

                pltcall = obj->pltgot;

                dbg(" reloc_jmpslot: indir, reloff=%x, N=%x\n",
                    reloff, N);

                jmptab = obj->pltgot + JMPTAB_BASE(N);
                jmptab[reloff] = target;
                mb(); /* Order jmptab update before next changes */

                if (reloff < PLT_EXTENDED_BEGIN) {
                        /* for extended PLT entries, we keep the old code */

                        distance = (Elf_Addr)pltcall - (Elf_Addr)(wherep + 1);

                        /* li   r11,reloff */
                        /* b    pltcall  # use indirect pltcall routine */

                        /* first instruction same as before */
                        wherep[1] = 0x48000000 | (distance & 0x03fffffc);
                        __syncicache(wherep, 8);
                }
        }

out:
        return (target);
}

int
reloc_iresolve(Obj_Entry *obj,
    struct Struct_RtldLockState *lockstate)
{
        /*
         * Since PLT slots on PowerPC are always R_PPC_JMP_SLOT,
         * R_PPC_IRELATIVE is in RELA.
         */
        const Elf_Rela *relalim;
        const Elf_Rela *rela;
        Elf_Addr *where, target, *ptr;

        if (!obj->irelative)
                return (0);

        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_PPC_IRELATIVE) {
                        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;
                }
        }
        /*
         * XXX Remove me when lld is fixed!
         * LLD currently makes illegal relocations in the PLT.
         */
        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_PPC_IRELATIVE) {
                        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;
                }
        }

        obj->irelative = false;
        return (0);
}

int
reloc_iresolve_nonplt(Obj_Entry *obj __unused,
    struct Struct_RtldLockState *lockstate __unused)
{
        return (0);
}

int
reloc_gnu_ifunc(Obj_Entry *obj __unused, int flags __unused,
    struct Struct_RtldLockState *lockstate __unused)
{
        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_PPC_JMP_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);
}

/*
 * Setup the plt glue routines.
 */
#define PLTCALL_SIZE            20
#define PLTLONGRESOLVE_SIZE     20
#define PLTRESOLVE_SIZE         24

void
init_pltgot(Obj_Entry *obj)
{
        Elf_Word *pltcall, *pltresolve, *pltlongresolve;
        Elf_Word *jmptab;
        int N = obj->pltrelasize / sizeof(Elf_Rela);

        pltcall = obj->pltgot;

        if (pltcall == NULL) {
                return;
        }

        /* Handle Secure-PLT first, if applicable. */
        if (obj->gotptr != NULL) {
                obj->gotptr[1] = (Elf_Addr)_rtld_bind_secureplt_start;
                obj->gotptr[2] = (Elf_Addr)obj;
                dbg("obj %s secure-plt gotptr=%p start=%p obj=%p",
                    obj->path, obj->gotptr,
                    (void *)obj->gotptr[1], (void *)obj->gotptr[2]);
                return;
        }

        /*
         * From the SVR4 PPC ABI:
         *
         * 'The first 18 words (72 bytes) of the PLT are reserved for
         * use by the dynamic linker.
         *   ...
         * 'If the executable or shared object requires N procedure
         *  linkage table entries, the link editor shall reserve 3*N
         *  words (12*N bytes) following the 18 reserved words. The
         *  first 2*N of these words are the procedure linkage table
         *  entries themselves. The static linker directs calls to bytes
         *  (72 + (i-1)*8), for i between 1 and N inclusive. The remaining
         *  N words (4*N bytes) are reserved for use by the dynamic linker.'
         */

        /*
         * Copy the absolute-call assembler stub into the first part of
         * the reserved PLT area.
         */
        memcpy(pltcall, _rtld_powerpc_pltcall, PLTCALL_SIZE);

        /*
         * Determine the address of the jumptable, which is the dyn-linker
         * reserved area after the call cells. Write the absolute address
         * of the jumptable into the absolute-call assembler code so it
         * can determine this address.
         */
        jmptab = obj->pltgot + JMPTAB_BASE(N);
        pltcall[1] |= _ppc_ha(jmptab);     /* addis 11,11,jmptab@ha */
        pltcall[2] |= _ppc_la(jmptab);     /* lwz   11,jmptab@l(11) */

        /*
         * Skip down 20 bytes into the initial reserved area and copy
         * in the standard resolving assembler call. Into this assembler,
         * insert the absolute address of the _rtld_bind_start routine
         * and the address of the relocation object.
         *
         * We place pltlongresolve first, so it can fix up its arguments
         * and then fall through to the regular PLT resolver.
         */
        pltlongresolve = obj->pltgot + 5;

        memcpy(pltlongresolve, _rtld_powerpc_pltlongresolve,
            PLTLONGRESOLVE_SIZE);
        pltlongresolve[0] |= _ppc_ha(jmptab);   /* lis  12,jmptab@ha    */
        pltlongresolve[1] |= _ppc_la(jmptab);   /* addi 12,12,jmptab@l  */

        pltresolve = pltlongresolve + PLTLONGRESOLVE_SIZE/sizeof(uint32_t);
        memcpy(pltresolve, _rtld_powerpc_pltresolve, PLTRESOLVE_SIZE);
        pltresolve[0] |= _ppc_ha(_rtld_bind_start);
        pltresolve[1] |= _ppc_la(_rtld_bind_start);
        pltresolve[3] |= _ppc_ha(obj);
        pltresolve[4] |= _ppc_la(obj);

        /*
         * The icache will be sync'd in reloc_plt, which is called
         * after all the slots have been updated
         */
}

/*
 * 32 bit cpu feature flag fields.
 */
u_long cpu_features;
u_long cpu_features2;

void
powerpc_abi_variant_hook(Elf_Auxinfo** aux_info)
{
        /*
         * Since aux_info[] is easier to work with than aux, go ahead and
         * initialize cpu_features / cpu_features2.
         */
        cpu_features = -1UL;
        cpu_features2 = -1UL;
        if (aux_info[AT_HWCAP] != NULL)
                cpu_features = aux_info[AT_HWCAP]->a_un.a_val;
        if (aux_info[AT_HWCAP2] != NULL)
                cpu_features2 = aux_info[AT_HWCAP2]->a_un.a_val;
}

void
ifunc_init(Elf_Auxinfo *aux_info[__min_size(AT_COUNT)] __unused)
{

}

void
allocate_initial_tls(Obj_Entry *list)
{

        /*
        * 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(list, 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 +
            TLS_DTV_OFFSET));
}

void
arch_fix_auxv(Elf_Auxinfo *aux, Elf_Auxinfo *aux_info[])
{
        Elf_Auxinfo *auxp;

        for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
                if (auxp->a_type == 23) /* AT_STACKPROT */
                        return;
        }

        /* Remap from old-style auxv numbers. */
        aux_info[23] = aux_info[21]; /* AT_STACKPROT */
        aux_info[21] = aux_info[19]; /* AT_PAGESIZESLEN */
        aux_info[19] = aux_info[17]; /* AT_NCPUS */
        aux_info[17] = aux_info[15]; /* AT_CANARYLEN */
        aux_info[15] = aux_info[13]; /* AT_EXECPATH */
        aux_info[13] = NULL;         /* AT_GID */

        aux_info[20] = aux_info[18]; /* AT_PAGESIZES */
        aux_info[18] = aux_info[16]; /* AT_OSRELDATE */
        aux_info[16] = aux_info[14]; /* AT_CANARY */
        aux_info[14] = NULL;         /* AT_EGID */
}