MIPS64 code uses rela-style relocs, and MIPS64r6 modules may include the new R_MIPS_PC21 & R_MIPS_PC26 relocations. We thus need to support these relocations in order to load MIPS64r6 kernel modules. They are similar to the existing R_MIPS_PC16 relocation but applying to a wider field. Implement support for them by genericising the existing R_MIPS_PC16 implementation such that it can be used for different field widths, and calling it for all 3 reloc types.
Signed-off-by: Paul Burton <[email protected]> --- Changes in v2: None arch/mips/include/asm/elf.h | 5 +++++ arch/mips/kernel/module-rela.c | 48 +++++++++++++++++++++++++++++++++++++++++- 2 files changed, 52 insertions(+), 1 deletion(-) diff --git a/arch/mips/include/asm/elf.h b/arch/mips/include/asm/elf.h index cefb7a5..7cec234 100644 --- a/arch/mips/include/asm/elf.h +++ b/arch/mips/include/asm/elf.h @@ -111,6 +111,11 @@ #define R_MIPS_CALLHI16 30 #define R_MIPS_CALLLO16 31 /* + * Introduced for MIPSr6. + */ +#define R_MIPS_PC21_S2 60 +#define R_MIPS_PC26_S2 61 +/* * This range is reserved for vendor specific relocations. */ #define R_MIPS_LOVENDOR 100 diff --git a/arch/mips/kernel/module-rela.c b/arch/mips/kernel/module-rela.c index 0570676..b361142 100644 --- a/arch/mips/kernel/module-rela.c +++ b/arch/mips/kernel/module-rela.c @@ -16,6 +16,7 @@ * Copyright (C) 2001 Rusty Russell. * Copyright (C) 2003, 2004 Ralf Baechle ([email protected]) * Copyright (C) 2005 Thiemo Seufer + * Copyright (C) 2015 Imagination Technologies Ltd. */ #include <linux/elf.h> @@ -65,6 +66,48 @@ static int apply_r_mips_lo16_rela(struct module *me, u32 *location, Elf_Addr v) return 0; } +static int apply_r_mips_pc_rela(struct module *me, u32 *location, Elf_Addr v, + unsigned 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 RELA relocation\n", + me->name, bits); + return -ENOEXEC; + } + + offset = ((long)v - (long)location) >> 2; + + /* check the sign bit onwards are identical - ie. we didn't overflow */ + se_bits = (offset & BIT(bits - 1)) ? ~0ul : 0; + if ((offset & ~mask) != (se_bits & ~mask)) { + pr_err("module %s: relocation overflow\n", me->name); + return -ENOEXEC; + } + + *location = (*location & ~mask) | (offset & mask); + + return 0; +} + +static int apply_r_mips_pc16_rela(struct module *me, u32 *location, Elf_Addr v) +{ + return apply_r_mips_pc_rela(me, location, v, 16); +} + +static int apply_r_mips_pc21_rela(struct module *me, u32 *location, Elf_Addr v) +{ + return apply_r_mips_pc_rela(me, location, v, 21); +} + +static int apply_r_mips_pc26_rela(struct module *me, u32 *location, Elf_Addr v) +{ + return apply_r_mips_pc_rela(me, location, v, 26); +} + static int apply_r_mips_64_rela(struct module *me, u32 *location, Elf_Addr v) { *(Elf_Addr *)location = v; @@ -97,9 +140,12 @@ static int (*reloc_handlers_rela[]) (struct module *me, u32 *location, [R_MIPS_26] = apply_r_mips_26_rela, [R_MIPS_HI16] = apply_r_mips_hi16_rela, [R_MIPS_LO16] = apply_r_mips_lo16_rela, + [R_MIPS_PC16] = apply_r_mips_pc16_rela, [R_MIPS_64] = apply_r_mips_64_rela, [R_MIPS_HIGHER] = apply_r_mips_higher_rela, - [R_MIPS_HIGHEST] = apply_r_mips_highest_rela + [R_MIPS_HIGHEST] = apply_r_mips_highest_rela, + [R_MIPS_PC21_S2] = apply_r_mips_pc21_rela, + [R_MIPS_PC26_S2] = apply_r_mips_pc26_rela, }; int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, -- 2.7.0
