/*      $OpenBSD: rtld_machine.c,v 1.7 2022/01/08 06:49:42 guenther Exp $ */

/*
 * Copyright (c) 1999 Dale Rahn
 *
 * 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 ``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.
 *
 */

#define _DYN_LOADER

#include <sys/types.h>
#include <sys/exec_elf.h>
#include <sys/syscall.h>
#include <sys/unistd.h>

#include <machine/reloc.h>

#include "util.h"
#include "resolve.h"

#define DT_PROC(n)      ((n) - DT_LOPROC + DT_NUM)

int64_t pcookie __attribute__((section(".openbsd.randomdata"))) __dso_hidden;

/* relocation bits */
#define B24_VALID_RANGE(x) \
    ((((x) & 0xfe000000) == 0x00000000) || (((x) &  0xfe000000) == 0xfe000000))

void _dl_bind_start(void); /* XXX */
Elf_Addr _dl_bind(elf_object_t *object, int reloff);

int
_dl_md_reloc(elf_object_t *object, int rel, int relasz)
{
        int     i;
        int     numrela;
        long    relrel;
        int     fails = 0;
        Elf_Addr loff;
        Elf_RelA  *relas;
        /* for jmp table relocations */
        Elf_Addr prev_value = 0, prev_ooff = 0;
        const Elf_Sym *prev_sym = NULL;

        loff = object->obj_base;
        numrela = object->Dyn.info[relasz] / sizeof(Elf_RelA);
        relrel = rel == DT_RELA ? object->relacount : 0;
        relas = (Elf_RelA *)(object->Dyn.info[rel]);

        if (relas == NULL)
                return 0;

        if (relrel > numrela)
                _dl_die("relcount > numrel: %ld > %d", relrel, numrela);

        /* tight loop for leading RELATIVE relocs */
        for (i = 0; i < relrel; i++, relas++) {
                Elf_Addr *r_addr;

                r_addr = (Elf_Addr *)(relas->r_offset + loff);
                *r_addr = loff + relas->r_addend;
        }
        for (; i < numrela; i++, relas++) {
                Elf_Addr *r_addr = (Elf_Addr *)(relas->r_offset + loff);
                const Elf_Sym *sym;
                const char *symn;
                int type;

                if (ELF_R_SYM(relas->r_info) == 0xffffff)
                        continue;

                type = ELF_R_TYPE(relas->r_info);

                if (type == R_PPC64_JMP_SLOT && rel != DT_JMPREL)
                        continue;

                sym = object->dyn.symtab;
                sym += ELF_R_SYM(relas->r_info);
                symn = object->dyn.strtab + sym->st_name;

                if (ELF_R_SYM(relas->r_info) &&
                    !(ELF_ST_BIND(sym->st_info) == STB_LOCAL &&
                    ELF_ST_TYPE (sym->st_info) == STT_NOTYPE) &&
                    sym != prev_sym) {
                        struct sym_res sr;

                        sr = _dl_find_symbol(symn,
                            SYM_SEARCH_ALL|SYM_WARNNOTFOUND|
                            ((type == R_PPC64_JMP_SLOT) ?
                            SYM_PLT:SYM_NOTPLT), sym, object);

                        if (sr.sym == NULL) {
                                if (ELF_ST_BIND(sym->st_info) != STB_WEAK)
                                        fails++;
                                continue;
                        }
                        prev_sym = sym;
                        prev_value = sr.sym->st_value;
                        prev_ooff = sr.obj->obj_base;
                }

                switch (type) {
                case R_PPC64_ADDR64:
                        if (ELF_ST_BIND(sym->st_info) == STB_LOCAL &&
                            (ELF_ST_TYPE(sym->st_info) == STT_SECTION ||
                            ELF_ST_TYPE(sym->st_info) == STT_NOTYPE) ) {
                                *r_addr = prev_ooff + relas->r_addend;
                        } else {
                                *r_addr = prev_ooff + prev_value +
                                    relas->r_addend;
                        }
                        break;
                case R_PPC64_RELATIVE:
                        if (ELF_ST_BIND(sym->st_info) == STB_LOCAL &&
                            (ELF_ST_TYPE(sym->st_info) == STT_SECTION ||
                            ELF_ST_TYPE(sym->st_info) == STT_NOTYPE) ) {
                                *r_addr = loff + relas->r_addend;
                        } else {
                                *r_addr = loff + prev_value +
                                    relas->r_addend;
                        }
                        break;
                /*
                 * For Secure-PLT, RELOC_JMP_SLOT simply sets PLT
                 * slots similarly to how RELOC_GLOB_DAT updates GOT
                 * slots.
                 */
                case R_PPC64_JMP_SLOT:
                case R_PPC64_GLOB_DAT:
                        *r_addr = prev_ooff + prev_value + relas->r_addend;
                        break;
#if 0
                /* should not be supported ??? */
                case RELOC_REL24:
                    {
                        Elf_Addr val = prev_ooff + prev_value +
                            relas->r_addend - (Elf_Addr)r_addr;
                        if (!B24_VALID_RANGE(val)) {
                                /* invalid offset */
                                _dl_die("%s: invalid %s offset %llx at %p",
                                    object->load_name, "REL24", val,
                                    (void *)r_addr);
                        }
                        val &= ~0xfc000003;
                        val |= (*r_addr & 0xfc000003);
                        *r_addr = val;

                        _dl_dcbf(r_addr);
                    }
                break;
#endif
#if 0
                case RELOC_16_LO:
                    {
                        Elf_Addr val;

                        val = loff + relas->r_addend;
                        *(Elf_Half *)r_addr = val;

                        _dl_dcbf(r_addr);
                    }
                break;
#endif
#if 0
                case RELOC_16_HI:
                    {
                        Elf_Addr val;

                        val = loff + relas->r_addend;
                        *(Elf_Half *)r_addr = (val >> 16);

                        _dl_dcbf(r_addr);
                    }
                break;
#endif
#if 0
                case RELOC_16_HA:
                    {
                        Elf_Addr val;

                        val = loff + relas->r_addend;
                        *(Elf_Half *)r_addr = ((val + 0x8000) >> 16);

                        _dl_dcbf(r_addr);
                    }
                break;
#endif
#if 0
                case RELOC_REL14_TAKEN:
                        /* val |= 1 << (31-10) XXX? */
                case RELOC_REL14:
                case RELOC_REL14_NTAKEN:
                    {
                        Elf_Addr val = prev_ooff + prev_value +
                            relas->r_addend - (Elf_Addr)r_addr;
                        if (((val & 0xffff8000) != 0) &&
                            ((val & 0xffff8000) != 0xffff8000)) {
                                /* invalid offset */
                                _dl_die("%s: invalid %s offset %llx at %p",
                                    object->load_name, "REL14", val,
                                    (void *)r_addr);
                        }
                        val &= ~0xffff0003;
                        val |= (*r_addr & 0xffff0003);
                        *r_addr = val;
                        _dl_dcbf(r_addr);
                    }
                        break;
#endif
                case R_PPC64_COPY:
                {
                        struct sym_res sr;
                        /*
                         * we need to find a symbol, that is not in the current
                         * object, start looking at the beginning of the list,
                         * searching all objects but _not_ the current object,
                         * first one found wins.
                         */
                        sr = _dl_find_symbol(symn,
                            SYM_SEARCH_OTHER|SYM_WARNNOTFOUND| SYM_NOTPLT,
                            sym, object);
                        if (sr.sym != NULL) {
                                _dl_bcopy((void *)(sr.obj->obj_base + sr.sym->st_value),
                                    r_addr, sym->st_size);
                        } else
                                fails++;
                }
                        break;
                case R_PPC64_NONE:
                        break;

                default:
                        _dl_die("%s: unsupported relocation '%s' %lld at %p\n",
                            object->load_name, symn,
                            ELF_R_TYPE(relas->r_info), (void *)r_addr );
                }
        }

        return fails;
}

/*
 *      Relocate the Global Offset Table (GOT).
 *      This is done by calling _dl_md_reloc on DT_JMPREL for DL_BIND_NOW,
 *      otherwise the lazy binding plt initialization is performed.
 */
int
_dl_md_reloc_got(elf_object_t *object, int lazy)
{
        int fails = 0;

        if (object->Dyn.info[DT_PLTREL] != DT_RELA)
                return 0;

        if (!lazy) {
                fails = _dl_md_reloc(object, DT_JMPREL, DT_PLTRELSZ);
        } else {
                Elf_Addr *plt;
                int numplt, n;

                /* Relocate processor-specific tags. */
                object->Dyn.info[DT_PROC(DT_PPC64_GLINK)] += object->obj_base;

                plt = (Elf_Addr *)
                   (Elf_RelA *)(object->Dyn.info[DT_PLTGOT]);
                numplt = object->Dyn.info[DT_PLTRELSZ] / sizeof(Elf_RelA);
                plt[0] = (uint64_t)_dl_bind_start;
                plt[1] = (uint64_t)object;
                for (n = 0; n < numplt; n++) {
                        plt[n + 2] = object->Dyn.info[DT_PROC(DT_PPC64_GLINK)] +
                            n * 4 + 32;
                }
        }

        return fails;
}

Elf_Addr
_dl_bind(elf_object_t *object, int relidx)
{
        const Elf_Sym *sym;
        struct sym_res sr;
        const char *symn;
        Elf_RelA *relas;
        Elf_Addr *plttable;
        int64_t cookie = pcookie;
        struct {
                struct __kbind param;
                Elf_Addr newval;
        } buf;

        relas = ((Elf_RelA *)object->Dyn.info[DT_JMPREL]) + relidx;

        sym = object->dyn.symtab;
        sym += ELF_R_SYM(relas->r_info);
        symn = object->dyn.strtab + sym->st_name;

        sr = _dl_find_symbol(symn, SYM_SEARCH_ALL|SYM_WARNNOTFOUND|SYM_PLT,
            sym, object);
        if (sr.sym == NULL)
                _dl_die("lazy binding failed!");

        buf.newval = sr.obj->obj_base + sr.sym->st_value;

        if (__predict_false(sr.obj->traced) && _dl_trace_plt(sr.obj, symn))
                return buf.newval;

        plttable = (Elf_Addr *)(Elf_RelA *)(object->Dyn.info[DT_PLTGOT]);
        buf.param.kb_addr = &plttable[relidx + 2];
        buf.param.kb_size = sizeof(Elf_Addr);

        {
                register long syscall_num __asm("r0") = SYS_kbind;
                register void *arg1 __asm("r3") = &buf.param;
                register long  arg2 __asm("r4") = sizeof(struct __kbind) +
                    sizeof(Elf_Addr);
                register long  arg3 __asm("r5") = cookie;

                __asm volatile("sc" : "+r" (syscall_num), "+r" (arg1),
                    "+r" (arg2) : "r" (arg3) : "cc", "memory");
        }

        return buf.newval;
}