// SPDX-License-Identifier: GPL-2.0
/* This is included from relocs_32/64.c */

#define ElfW(type)              _ElfW(ELF_BITS, type)
#define _ElfW(bits, type)       __ElfW(bits, type)
#define __ElfW(bits, type)      Elf##bits##_##type

#define Elf_Addr                ElfW(Addr)
#define Elf_Ehdr                ElfW(Ehdr)
#define Elf_Phdr                ElfW(Phdr)
#define Elf_Shdr                ElfW(Shdr)
#define Elf_Sym                 ElfW(Sym)

static Elf_Ehdr ehdr;

struct relocs {
        uint32_t        *offset;
        unsigned long   count;
        unsigned long   size;
};

static struct relocs relocs;

struct section {
        Elf_Shdr       shdr;
        struct section *link;
        Elf_Sym        *symtab;
        Elf_Rel        *reltab;
        char           *strtab;
        long           shdr_offset;
};
static struct section *secs;

static const char * const regex_sym_kernel = {
/* Symbols matching these regex's should never be relocated */
        "^(__crc_)",
};

static regex_t sym_regex_c;

static int regex_skip_reloc(const char *sym_name)
{
        return !regexec(&sym_regex_c, sym_name, 0, NULL, 0);
}

static void regex_init(void)
{
        char errbuf[128];
        int err;

        err = regcomp(&sym_regex_c, regex_sym_kernel,
                        REG_EXTENDED|REG_NOSUB);

        if (err) {
                regerror(err, &sym_regex_c, errbuf, sizeof(errbuf));
                die("%s", errbuf);
        }
}

static const char *rel_type(unsigned type)
{
        static const char * const type_name[] = {
#define REL_TYPE(X)[X] = #X
                REL_TYPE(R_MIPS_NONE),
                REL_TYPE(R_MIPS_16),
                REL_TYPE(R_MIPS_32),
                REL_TYPE(R_MIPS_REL32),
                REL_TYPE(R_MIPS_26),
                REL_TYPE(R_MIPS_HI16),
                REL_TYPE(R_MIPS_LO16),
                REL_TYPE(R_MIPS_GPREL16),
                REL_TYPE(R_MIPS_LITERAL),
                REL_TYPE(R_MIPS_GOT16),
                REL_TYPE(R_MIPS_PC16),
                REL_TYPE(R_MIPS_CALL16),
                REL_TYPE(R_MIPS_GPREL32),
                REL_TYPE(R_MIPS_64),
                REL_TYPE(R_MIPS_HIGHER),
                REL_TYPE(R_MIPS_HIGHEST),
                REL_TYPE(R_MIPS_PC21_S2),
                REL_TYPE(R_MIPS_PC26_S2),
                REL_TYPE(R_MIPS_PC32),
#undef REL_TYPE
        };
        const char *name = "unknown type rel type name";

        if (type < ARRAY_SIZE(type_name) && type_name[type])
                name = type_name[type];
        return name;
}

static const char *sec_name(unsigned shndx)
{
        const char *sec_strtab;
        const char *name;

        sec_strtab = secs[ehdr.e_shstrndx].strtab;
        if (shndx < ehdr.e_shnum)
                name = sec_strtab + secs[shndx].shdr.sh_name;
        else if (shndx == SHN_ABS)
                name = "ABSOLUTE";
        else if (shndx == SHN_COMMON)
                name = "COMMON";
        else
                name = "<noname>";
        return name;
}

static struct section *sec_lookup(const char *secname)
{
        int i;

        for (i = 0; i < ehdr.e_shnum; i++)
                if (strcmp(secname, sec_name(i)) == 0)
                        return &secs[i];

        return NULL;
}

static const char *sym_name(const char *sym_strtab, Elf_Sym *sym)
{
        const char *name;

        if (sym->st_name)
                name = sym_strtab + sym->st_name;
        else
                name = sec_name(sym->st_shndx);
        return name;
}

#if BYTE_ORDER == LITTLE_ENDIAN
#define le16_to_cpu(val) (val)
#define le32_to_cpu(val) (val)
#define le64_to_cpu(val) (val)
#define be16_to_cpu(val) bswap_16(val)
#define be32_to_cpu(val) bswap_32(val)
#define be64_to_cpu(val) bswap_64(val)

#define cpu_to_le16(val) (val)
#define cpu_to_le32(val) (val)
#define cpu_to_le64(val) (val)
#define cpu_to_be16(val) bswap_16(val)
#define cpu_to_be32(val) bswap_32(val)
#define cpu_to_be64(val) bswap_64(val)
#endif
#if BYTE_ORDER == BIG_ENDIAN
#define le16_to_cpu(val) bswap_16(val)
#define le32_to_cpu(val) bswap_32(val)
#define le64_to_cpu(val) bswap_64(val)
#define be16_to_cpu(val) (val)
#define be32_to_cpu(val) (val)
#define be64_to_cpu(val) (val)

#define cpu_to_le16(val) bswap_16(val)
#define cpu_to_le32(val) bswap_32(val)
#define cpu_to_le64(val) bswap_64(val)
#define cpu_to_be16(val) (val)
#define cpu_to_be32(val) (val)
#define cpu_to_be64(val) (val)
#endif

static uint16_t elf16_to_cpu(uint16_t val)
{
        if (ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
                return le16_to_cpu(val);
        else
                return be16_to_cpu(val);
}

static uint32_t elf32_to_cpu(uint32_t val)
{
        if (ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
                return le32_to_cpu(val);
        else
                return be32_to_cpu(val);
}

static uint32_t cpu_to_elf32(uint32_t val)
{
        if (ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
                return cpu_to_le32(val);
        else
                return cpu_to_be32(val);
}

#define elf_half_to_cpu(x)      elf16_to_cpu(x)
#define elf_word_to_cpu(x)      elf32_to_cpu(x)

#if ELF_BITS == 64
static uint64_t elf64_to_cpu(uint64_t val)
{
        if (ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
                return le64_to_cpu(val);
        else
                return be64_to_cpu(val);
}
#define elf_addr_to_cpu(x)      elf64_to_cpu(x)
#define elf_off_to_cpu(x)       elf64_to_cpu(x)
#define elf_xword_to_cpu(x)     elf64_to_cpu(x)
#else
#define elf_addr_to_cpu(x)      elf32_to_cpu(x)
#define elf_off_to_cpu(x)       elf32_to_cpu(x)
#define elf_xword_to_cpu(x)     elf32_to_cpu(x)
#endif

static void read_ehdr(FILE *fp)
{
        if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1)
                die("Cannot read ELF header: %s\n", strerror(errno));

        if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0)
                die("No ELF magic\n");

        if (ehdr.e_ident[EI_CLASS] != ELF_CLASS)
                die("Not a %d bit executable\n", ELF_BITS);

        if ((ehdr.e_ident[EI_DATA] != ELFDATA2LSB) &&
            (ehdr.e_ident[EI_DATA] != ELFDATA2MSB))
                die("Unknown ELF Endianness\n");

        if (ehdr.e_ident[EI_VERSION] != EV_CURRENT)
                die("Unknown ELF version\n");

        /* Convert the fields to native endian */
        ehdr.e_type      = elf_half_to_cpu(ehdr.e_type);
        ehdr.e_machine   = elf_half_to_cpu(ehdr.e_machine);
        ehdr.e_version   = elf_word_to_cpu(ehdr.e_version);
        ehdr.e_entry     = elf_addr_to_cpu(ehdr.e_entry);
        ehdr.e_phoff     = elf_off_to_cpu(ehdr.e_phoff);
        ehdr.e_shoff     = elf_off_to_cpu(ehdr.e_shoff);
        ehdr.e_flags     = elf_word_to_cpu(ehdr.e_flags);
        ehdr.e_ehsize    = elf_half_to_cpu(ehdr.e_ehsize);
        ehdr.e_phentsize = elf_half_to_cpu(ehdr.e_phentsize);
        ehdr.e_phnum     = elf_half_to_cpu(ehdr.e_phnum);
        ehdr.e_shentsize = elf_half_to_cpu(ehdr.e_shentsize);
        ehdr.e_shnum     = elf_half_to_cpu(ehdr.e_shnum);
        ehdr.e_shstrndx  = elf_half_to_cpu(ehdr.e_shstrndx);

        if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN))
                die("Unsupported ELF header type\n");

        if (ehdr.e_machine != ELF_MACHINE)
                die("Not for %s\n", ELF_MACHINE_NAME);

        if (ehdr.e_version != EV_CURRENT)
                die("Unknown ELF version\n");

        if (ehdr.e_ehsize != sizeof(Elf_Ehdr))
                die("Bad ELF header size\n");

        if (ehdr.e_phentsize != sizeof(Elf_Phdr))
                die("Bad program header entry\n");

        if (ehdr.e_shentsize != sizeof(Elf_Shdr))
                die("Bad section header entry\n");

        if (ehdr.e_shstrndx >= ehdr.e_shnum)
                die("String table index out of bounds\n");
}

static void read_shdrs(FILE *fp)
{
        int i;
        Elf_Shdr shdr;

        secs = calloc(ehdr.e_shnum, sizeof(struct section));
        if (!secs)
                die("Unable to allocate %d section headers\n", ehdr.e_shnum);

        if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0)
                die("Seek to %d failed: %s\n", ehdr.e_shoff, strerror(errno));

        for (i = 0; i < ehdr.e_shnum; i++) {
                struct section *sec = &secs[i];

                sec->shdr_offset = ftell(fp);
                if (fread(&shdr, sizeof(shdr), 1, fp) != 1)
                        die("Cannot read ELF section headers %d/%d: %s\n",
                            i, ehdr.e_shnum, strerror(errno));
                sec->shdr.sh_name      = elf_word_to_cpu(shdr.sh_name);
                sec->shdr.sh_type      = elf_word_to_cpu(shdr.sh_type);
                sec->shdr.sh_flags     = elf_xword_to_cpu(shdr.sh_flags);
                sec->shdr.sh_addr      = elf_addr_to_cpu(shdr.sh_addr);
                sec->shdr.sh_offset    = elf_off_to_cpu(shdr.sh_offset);
                sec->shdr.sh_size      = elf_xword_to_cpu(shdr.sh_size);
                sec->shdr.sh_link      = elf_word_to_cpu(shdr.sh_link);
                sec->shdr.sh_info      = elf_word_to_cpu(shdr.sh_info);
                sec->shdr.sh_addralign = elf_xword_to_cpu(shdr.sh_addralign);
                sec->shdr.sh_entsize   = elf_xword_to_cpu(shdr.sh_entsize);
                if (sec->shdr.sh_link < ehdr.e_shnum)
                        sec->link = &secs[sec->shdr.sh_link];
        }
}

static void read_strtabs(FILE *fp)
{
        int i;

        for (i = 0; i < ehdr.e_shnum; i++) {
                struct section *sec = &secs[i];

                if (sec->shdr.sh_type != SHT_STRTAB)
                        continue;

                sec->strtab = malloc(sec->shdr.sh_size);
                if (!sec->strtab)
                        die("malloc of %d bytes for strtab failed\n",
                            sec->shdr.sh_size);

                if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0)
                        die("Seek to %d failed: %s\n",
                            sec->shdr.sh_offset, strerror(errno));

                if (fread(sec->strtab, 1, sec->shdr.sh_size, fp) !=
                    sec->shdr.sh_size)
                        die("Cannot read symbol table: %s\n", strerror(errno));
        }
}

static void read_symtabs(FILE *fp)
{
        int i, j;

        for (i = 0; i < ehdr.e_shnum; i++) {
                struct section *sec = &secs[i];
                if (sec->shdr.sh_type != SHT_SYMTAB)
                        continue;

                sec->symtab = malloc(sec->shdr.sh_size);
                if (!sec->symtab)
                        die("malloc of %d bytes for symtab failed\n",
                            sec->shdr.sh_size);

                if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0)
                        die("Seek to %d failed: %s\n",
                            sec->shdr.sh_offset, strerror(errno));

                if (fread(sec->symtab, 1, sec->shdr.sh_size, fp) !=
                    sec->shdr.sh_size)
                        die("Cannot read symbol table: %s\n", strerror(errno));

                for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Sym); j++) {
                        Elf_Sym *sym = &sec->symtab[j];

                        sym->st_name  = elf_word_to_cpu(sym->st_name);
                        sym->st_value = elf_addr_to_cpu(sym->st_value);
                        sym->st_size  = elf_xword_to_cpu(sym->st_size);
                        sym->st_shndx = elf_half_to_cpu(sym->st_shndx);
                }
        }
}

static void read_relocs(FILE *fp)
{
        static unsigned long base;
        int i, j;

        if (!base) {
                struct section *sec = sec_lookup(".text");

                if (!sec)
                        die("Could not find .text section\n");

                base = sec->shdr.sh_addr;
        }

        for (i = 0; i < ehdr.e_shnum; i++) {
                struct section *sec = &secs[i];

                if (sec->shdr.sh_type != SHT_REL_TYPE)
                        continue;

                sec->reltab = malloc(sec->shdr.sh_size);
                if (!sec->reltab)
                        die("malloc of %d bytes for relocs failed\n",
                            sec->shdr.sh_size);

                if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0)
                        die("Seek to %d failed: %s\n",
                            sec->shdr.sh_offset, strerror(errno));

                if (fread(sec->reltab, 1, sec->shdr.sh_size, fp) !=
                    sec->shdr.sh_size)
                        die("Cannot read symbol table: %s\n", strerror(errno));

                for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
                        Elf_Rel *rel = &sec->reltab[j];

                        rel->r_offset = elf_addr_to_cpu(rel->r_offset);
                        /* Set offset into kernel image */
                        rel->r_offset -= base;
#if (ELF_BITS == 32)
                        rel->r_info   = elf_xword_to_cpu(rel->r_info);
#else
                        /* Convert MIPS64 RELA format - only the symbol
                         * index needs converting to native endianness
                         */
                        rel->r_info   = rel->r_info;
                        ELF_R_SYM(rel->r_info) = elf32_to_cpu(ELF_R_SYM(rel->r_info));
#endif
#if (SHT_REL_TYPE == SHT_RELA)
                        rel->r_addend = elf_xword_to_cpu(rel->r_addend);
#endif
                }
        }
}

static void remove_relocs(FILE *fp)
{
        int i;
        Elf_Shdr shdr;

        for (i = 0; i < ehdr.e_shnum; i++) {
                struct section *sec = &secs[i];

                if (sec->shdr.sh_type != SHT_REL_TYPE)
                        continue;

                if (fseek(fp, sec->shdr_offset, SEEK_SET) < 0)
                        die("Seek to %d failed: %s\n",
                            sec->shdr_offset, strerror(errno));

                if (fread(&shdr, sizeof(shdr), 1, fp) != 1)
                        die("Cannot read ELF section headers %d/%d: %s\n",
                            i, ehdr.e_shnum, strerror(errno));

                /* Set relocation section size to 0, effectively removing it.
                 * This is necessary due to lack of support for relocations
                 * in objcopy when creating 32bit elf from 64bit elf.
                 */
                shdr.sh_size = 0;

                if (fseek(fp, sec->shdr_offset, SEEK_SET) < 0)
                        die("Seek to %d failed: %s\n",
                            sec->shdr_offset, strerror(errno));

                if (fwrite(&shdr, sizeof(shdr), 1, fp) != 1)
                        die("Cannot write ELF section headers %d/%d: %s\n",
                            i, ehdr.e_shnum, strerror(errno));
        }
}

static void add_reloc(struct relocs *r, uint32_t offset, unsigned type)
{
        /* Relocation representation in binary table:
         * |76543210|76543210|76543210|76543210|
         * |  Type  |  offset from _text >> 2  |
         */
        offset >>= 2;
        if (offset > 0x00FFFFFF)
                die("Kernel image exceeds maximum size for relocation!\n");

        offset = (offset & 0x00FFFFFF) | ((type & 0xFF) << 24);

        if (r->count == r->size) {
                unsigned long newsize = r->size + 50000;
                void *mem = realloc(r->offset, newsize * sizeof(r->offset[0]));

                if (!mem)
                        die("realloc failed\n");

                r->offset = mem;
                r->size = newsize;
        }
        r->offset[r->count++] = offset;
}

static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *rel,
                        Elf_Sym *sym, const char *symname))
{
        int i;
        struct section *extab_sec = sec_lookup("__ex_table");
        int extab_index = extab_sec ? extab_sec - secs : -1;

        /* Walk through the relocations */
        for (i = 0; i < ehdr.e_shnum; i++) {
                char *sym_strtab;
                Elf_Sym *sh_symtab;
                struct section *sec_applies, *sec_symtab;
                int j;
                struct section *sec = &secs[i];

                if (sec->shdr.sh_type != SHT_REL_TYPE)
                        continue;

                if (sec->shdr.sh_info == extab_index)
                        continue;

                sec_symtab  = sec->link;
                sec_applies = &secs[sec->shdr.sh_info];
                if (!(sec_applies->shdr.sh_flags & SHF_ALLOC))
                        continue;

                sh_symtab = sec_symtab->symtab;
                sym_strtab = sec_symtab->link->strtab;
                for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
                        Elf_Rel *rel = &sec->reltab[j];
                        Elf_Sym *sym = &sh_symtab[ELF_R_SYM(rel->r_info)];
                        const char *symname = sym_name(sym_strtab, sym);

                        process(sec, rel, sym, symname);
                }
        }
}

static int do_reloc(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
                      const char *symname)
{
        unsigned r_type = ELF_R_TYPE(rel->r_info);
        unsigned bind = ELF_ST_BIND(sym->st_info);

        if ((bind == STB_WEAK) && (sym->st_value == 0)) {
                /* Don't relocate weak symbols without a target */
                return 0;
        }

        if (regex_skip_reloc(symname))
                return 0;

        switch (r_type) {
        case R_MIPS_NONE:
        case R_MIPS_REL32:
        case R_MIPS_PC16:
        case R_MIPS_PC21_S2:
        case R_MIPS_PC26_S2:
        case R_MIPS_PC32:
                /*
                 * NONE can be ignored and PC relative relocations don't
                 * need to be adjusted.
                 */
        case R_MIPS_HIGHEST:
        case R_MIPS_HIGHER:
                /* We support relocating within the same 4Gb segment only,
                 * thus leaving the top 32bits unchanged
                 */
        case R_MIPS_LO16:
                /* We support relocating by 64k jumps only
                 * thus leaving the bottom 16bits unchanged
                 */
                break;

        case R_MIPS_64:
        case R_MIPS_32:
        case R_MIPS_26:
        case R_MIPS_HI16:
                add_reloc(&relocs, rel->r_offset, r_type);
                break;

        default:
                die("Unsupported relocation type: %s (%d)\n",
                    rel_type(r_type), r_type);
                break;
        }

        return 0;
}

static int write_reloc_as_bin(uint32_t v, FILE *f)
{
        unsigned char buf[4];

        v = cpu_to_elf32(v);

        memcpy(buf, &v, sizeof(uint32_t));
        return fwrite(buf, 1, 4, f);
}

static int write_reloc_as_text(uint32_t v, FILE *f)
{
        int res;

        res = fprintf(f, "\t.long 0x%08"PRIx32"\n", v);
        if (res < 0)
                return res;
        else
                return sizeof(uint32_t);
}

static void emit_relocs(int as_text, int as_bin, FILE *outf)
{
        int i;
        int (*write_reloc)(uint32_t, FILE *) = write_reloc_as_bin;
        int size = 0;
        int size_reserved;
        struct section *sec_reloc;

        sec_reloc = sec_lookup(".data.reloc");
        if (!sec_reloc)
                die("Could not find relocation section\n");

        size_reserved = sec_reloc->shdr.sh_size;

        /* Collect up the relocations */
        walk_relocs(do_reloc);

        /* Print the relocations */
        if (as_text) {
                /* Print the relocations in a form suitable that
                 * gas will like.
                 */
                printf(".section \".data.reloc\",\"a\"\n");
                printf(".balign 4\n");
                /* Output text to stdout */
                write_reloc = write_reloc_as_text;
                outf = stdout;
        } else if (as_bin) {
                /* Output raw binary to stdout */
                outf = stdout;
        } else {
                /* Seek to offset of the relocation section.
                * Each relocation is then written into the
                * vmlinux kernel image.
                */
                if (fseek(outf, sec_reloc->shdr.sh_offset, SEEK_SET) < 0) {
                        die("Seek to %d failed: %s\n",
                                sec_reloc->shdr.sh_offset, strerror(errno));
                }
        }

        for (i = 0; i < relocs.count; i++)
                size += write_reloc(relocs.offset[i], outf);

        /* Print a stop, but only if we've actually written some relocs */
        if (size)
                size += write_reloc(0, outf);

        if (size > size_reserved)
                /* Die, but suggest a value for CONFIG_RELOCATION_TABLE_SIZE
                 * which will fix this problem and allow a bit of headroom
                 * if more kernel features are enabled
                 */
                die("Relocations overflow available space!\n" \
                    "Please adjust CONFIG_RELOCATION_TABLE_SIZE " \
                    "to at least 0x%08x\n", (size + 0x1000) & ~0xFFF);
}

/*
 * As an aid to debugging problems with different linkers
 * print summary information about the relocs.
 * Since different linkers tend to emit the sections in
 * different orders we use the section names in the output.
 */
static int do_reloc_info(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
                                const char *symname)
{
        printf("%16s  0x%08x  %16s  %40s  %16s\n",
                sec_name(sec->shdr.sh_info),
                (unsigned int)rel->r_offset,
                rel_type(ELF_R_TYPE(rel->r_info)),
                symname,
                sec_name(sym->st_shndx));
        return 0;
}

static void print_reloc_info(void)
{
        printf("%16s  %10s  %16s  %40s  %16s\n",
                "reloc section",
                "offset",
                "reloc type",
                "symbol",
                "symbol section");
        walk_relocs(do_reloc_info);
}

#if ELF_BITS == 64
# define process process_64
#else
# define process process_32
#endif

void process(FILE *fp, int as_text, int as_bin,
             int show_reloc_info, int keep_relocs)
{
        regex_init();
        read_ehdr(fp);
        read_shdrs(fp);
        read_strtabs(fp);
        read_symtabs(fp);
        read_relocs(fp);
        if (show_reloc_info) {
                print_reloc_info();
                return;
        }
        emit_relocs(as_text, as_bin, fp);
        if (!keep_relocs)
                remove_relocs(fp);
}