diff options
author | Paul Burton <paul.burton@imgtec.com> | 2017-03-30 11:37:45 -0700 |
---|---|---|
committer | Ralf Baechle <ralf@linux-mips.org> | 2017-06-28 12:22:38 +0200 |
commit | 430d0b88943afffd0da6d98799bf0afb008fd13f (patch) | |
tree | e8bca93c870fca98e8b88fc86a8c32492cee5744 /arch/mips/kernel/module.c | |
parent | 351b0940d473146923711bc943fc881354a4c1f3 (diff) | |
download | linux-430d0b88943afffd0da6d98799bf0afb008fd13f.tar.bz2 |
MIPS: module: Unify rel & rela reloc handling
The module load code has previously had entirely separate
implementations for rel & rela style relocs, which unnecessarily
duplicates a whole lot of code. Unify the implementations of both types
of reloc, sharing the bulk of the code.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/15832/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/kernel/module.c')
-rw-r--r-- | arch/mips/kernel/module.c | 195 |
1 files changed, 150 insertions, 45 deletions
diff --git a/arch/mips/kernel/module.c b/arch/mips/kernel/module.c index ddcfb59593b6..b250eb0c4fc1 100644 --- a/arch/mips/kernel/module.c +++ b/arch/mips/kernel/module.c @@ -53,22 +53,25 @@ void *module_alloc(unsigned long size) } #endif -int apply_r_mips_none(struct module *me, u32 *location, Elf_Addr v) +static int apply_r_mips_none(struct module *me, u32 *location, + u32 base, Elf_Addr v, bool rela) { return 0; } -static int apply_r_mips_32_rel(struct module *me, u32 *location, Elf_Addr v) +static int apply_r_mips_32(struct module *me, u32 *location, + u32 base, Elf_Addr v, bool rela) { - *location += v; + *location = base + v; return 0; } -static int apply_r_mips_26_rel(struct module *me, u32 *location, Elf_Addr v) +static int apply_r_mips_26(struct module *me, u32 *location, + u32 base, Elf_Addr v, bool rela) { if (v % 4) { - pr_err("module %s: dangerous R_MIPS_26 REL relocation\n", + pr_err("module %s: dangerous R_MIPS_26 relocation\n", me->name); return -ENOEXEC; } @@ -80,15 +83,22 @@ static int apply_r_mips_26_rel(struct module *me, u32 *location, Elf_Addr v) } *location = (*location & ~0x03ffffff) | - ((*location + (v >> 2)) & 0x03ffffff); + ((base + (v >> 2)) & 0x03ffffff); return 0; } -static int apply_r_mips_hi16_rel(struct module *me, u32 *location, Elf_Addr v) +static int apply_r_mips_hi16(struct module *me, u32 *location, + u32 base, Elf_Addr v, bool rela) { struct mips_hi16 *n; + if (rela) { + *location = (*location & 0xffff0000) | + ((((long long) v + 0x8000LL) >> 16) & 0xffff); + return 0; + } + /* * We cannot relocate this one now because we don't know the value of * the carry we need to add. Save the information, and let LO16 do the @@ -117,12 +127,18 @@ static void free_relocation_chain(struct mips_hi16 *l) } } -static int apply_r_mips_lo16_rel(struct module *me, u32 *location, Elf_Addr v) +static int apply_r_mips_lo16(struct module *me, u32 *location, + u32 base, Elf_Addr v, bool rela) { - unsigned long insnlo = *location; + unsigned long insnlo = base; struct mips_hi16 *l; Elf_Addr val, vallo; + if (rela) { + *location = (*location & 0xffff0000) | (v & 0xffff); + return 0; + } + /* Sign extend the addend we extract from the lo insn. */ vallo = ((insnlo & 0xffff) ^ 0x8000) - 0x8000; @@ -178,26 +194,26 @@ out_danger: free_relocation_chain(l); me->arch.r_mips_hi16_list = NULL; - pr_err("module %s: dangerous R_MIPS_LO16 REL relocation\n", me->name); + pr_err("module %s: dangerous R_MIPS_LO16 relocation\n", me->name); return -ENOEXEC; } -static int apply_r_mips_pc_rel(struct module *me, u32 *location, Elf_Addr v, - unsigned bits) +static int apply_r_mips_pc(struct module *me, u32 *location, u32 base, + Elf_Addr v, unsigned int bits) { unsigned long mask = GENMASK(bits - 1, 0); unsigned long se_bits; long offset; if (v % 4) { - pr_err("module %s: dangerous R_MIPS_PC%u REL relocation\n", + pr_err("module %s: dangerous R_MIPS_PC%u relocation\n", me->name, bits); return -ENOEXEC; } - /* retrieve & sign extend implicit addend */ - offset = *location & mask; + /* retrieve & sign extend implicit addend if any */ + offset = base & mask; offset |= (offset & BIT(bits - 1)) ? ~mask : 0; offset += ((long)v - (long)location) >> 2; @@ -214,56 +230,121 @@ static int apply_r_mips_pc_rel(struct module *me, u32 *location, Elf_Addr v, return 0; } -static int apply_r_mips_pc16_rel(struct module *me, u32 *location, Elf_Addr v) +static int apply_r_mips_pc16(struct module *me, u32 *location, + u32 base, Elf_Addr v, bool rela) { - return apply_r_mips_pc_rel(me, location, v, 16); + return apply_r_mips_pc(me, location, base, v, 16); } -static int apply_r_mips_pc21_rel(struct module *me, u32 *location, Elf_Addr v) +static int apply_r_mips_pc21(struct module *me, u32 *location, + u32 base, Elf_Addr v, bool rela) { - return apply_r_mips_pc_rel(me, location, v, 21); + return apply_r_mips_pc(me, location, base, v, 21); } -static int apply_r_mips_pc26_rel(struct module *me, u32 *location, Elf_Addr v) +static int apply_r_mips_pc26(struct module *me, u32 *location, + u32 base, Elf_Addr v, bool rela) { - return apply_r_mips_pc_rel(me, location, v, 26); + return apply_r_mips_pc(me, location, base, v, 26); } -static int (*reloc_handlers_rel[]) (struct module *me, u32 *location, - Elf_Addr v) = { +static int apply_r_mips_64(struct module *me, u32 *location, + u32 base, Elf_Addr v, bool rela) +{ + if (WARN_ON(!rela)) + return -EINVAL; + + *(Elf_Addr *)location = v; + + return 0; +} + +static int apply_r_mips_higher(struct module *me, u32 *location, + u32 base, Elf_Addr v, bool rela) +{ + if (WARN_ON(!rela)) + return -EINVAL; + + *location = (*location & 0xffff0000) | + ((((long long)v + 0x80008000LL) >> 32) & 0xffff); + + return 0; +} + +static int apply_r_mips_highest(struct module *me, u32 *location, + u32 base, Elf_Addr v, bool rela) +{ + if (WARN_ON(!rela)) + return -EINVAL; + + *location = (*location & 0xffff0000) | + ((((long long)v + 0x800080008000LL) >> 48) & 0xffff); + + return 0; +} + +/** + * reloc_handler() - Apply a particular relocation to a module + * @me: the module to apply the reloc to + * @location: the address at which the reloc is to be applied + * @base: the existing value at location for REL-style; 0 for RELA-style + * @v: the value of the reloc, with addend for RELA-style + * + * Each implemented reloc_handler function applies a particular type of + * relocation to the module @me. Relocs that may be found in either REL or RELA + * variants can be handled by making use of the @base & @v parameters which are + * set to values which abstract the difference away from the particular reloc + * implementations. + * + * Return: 0 upon success, else -ERRNO + */ +typedef int (*reloc_handler)(struct module *me, u32 *location, + u32 base, Elf_Addr v, bool rela); + +/* The handlers for known reloc types */ +static reloc_handler reloc_handlers[] = { [R_MIPS_NONE] = apply_r_mips_none, - [R_MIPS_32] = apply_r_mips_32_rel, - [R_MIPS_26] = apply_r_mips_26_rel, - [R_MIPS_HI16] = apply_r_mips_hi16_rel, - [R_MIPS_LO16] = apply_r_mips_lo16_rel, - [R_MIPS_PC16] = apply_r_mips_pc16_rel, - [R_MIPS_PC21_S2] = apply_r_mips_pc21_rel, - [R_MIPS_PC26_S2] = apply_r_mips_pc26_rel, + [R_MIPS_32] = apply_r_mips_32, + [R_MIPS_26] = apply_r_mips_26, + [R_MIPS_HI16] = apply_r_mips_hi16, + [R_MIPS_LO16] = apply_r_mips_lo16, + [R_MIPS_PC16] = apply_r_mips_pc16, + [R_MIPS_64] = apply_r_mips_64, + [R_MIPS_HIGHER] = apply_r_mips_higher, + [R_MIPS_HIGHEST] = apply_r_mips_highest, + [R_MIPS_PC21_S2] = apply_r_mips_pc21, + [R_MIPS_PC26_S2] = apply_r_mips_pc26, }; -int apply_relocate(Elf_Shdr *sechdrs, const char *strtab, - unsigned int symindex, unsigned int relsec, - struct module *me) +static int __apply_relocate(Elf_Shdr *sechdrs, const char *strtab, + unsigned int symindex, unsigned int relsec, + struct module *me, bool rela) { - Elf_Mips_Rel *rel = (void *) sechdrs[relsec].sh_addr; - int (*handler)(struct module *me, u32 *location, Elf_Addr v); + union { + Elf_Mips_Rel *rel; + Elf_Mips_Rela *rela; + } r; + reloc_handler handler; Elf_Sym *sym; - u32 *location; + u32 *location, base; unsigned int i, type; Elf_Addr v; int err = 0; + size_t reloc_sz; pr_debug("Applying relocate section %u to %u\n", relsec, sechdrs[relsec].sh_info); + r.rel = (void *)sechdrs[relsec].sh_addr; + reloc_sz = rela ? sizeof(*r.rela) : sizeof(*r.rel); me->arch.r_mips_hi16_list = NULL; - for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { + for (i = 0; i < sechdrs[relsec].sh_size / reloc_sz; i++) { /* This is where to make the change */ location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr - + rel[i].r_offset; + + r.rel->r_offset; /* This is the symbol it is referring to */ sym = (Elf_Sym *)sechdrs[symindex].sh_addr - + ELF_MIPS_R_SYM(rel[i]); + + ELF_MIPS_R_SYM(*r.rel); if (sym->st_value >= -MAX_ERRNO) { /* Ignore unresolved weak symbol */ if (ELF_ST_BIND(sym->st_info) == STB_WEAK) @@ -274,10 +355,9 @@ int apply_relocate(Elf_Shdr *sechdrs, const char *strtab, goto out; } - type = ELF_MIPS_R_TYPE(rel[i]); - - if (type < ARRAY_SIZE(reloc_handlers_rel)) - handler = reloc_handlers_rel[type]; + type = ELF_MIPS_R_TYPE(*r.rel); + if (type < ARRAY_SIZE(reloc_handlers)) + handler = reloc_handlers[type]; else handler = NULL; @@ -288,8 +368,17 @@ int apply_relocate(Elf_Shdr *sechdrs, const char *strtab, goto out; } - v = sym->st_value; - err = handler(me, location, v); + if (rela) { + v = sym->st_value + r.rela->r_addend; + base = 0; + r.rela = &r.rela[1]; + } else { + v = sym->st_value; + base = *location; + r.rel = &r.rel[1]; + } + + err = handler(me, location, base, v, rela); if (err) goto out; } @@ -312,6 +401,22 @@ out: return err; } +int apply_relocate(Elf_Shdr *sechdrs, const char *strtab, + unsigned int symindex, unsigned int relsec, + struct module *me) +{ + return __apply_relocate(sechdrs, strtab, symindex, relsec, me, false); +} + +#ifdef CONFIG_MODULES_USE_ELF_RELA +int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, + unsigned int symindex, unsigned int relsec, + struct module *me) +{ + return __apply_relocate(sechdrs, strtab, symindex, relsec, me, true); +} +#endif /* CONFIG_MODULES_USE_ELF_RELA */ + /* Given an address, look for it in the module exception tables. */ const struct exception_table_entry *search_module_dbetables(unsigned long addr) { |