diff options
Diffstat (limited to 'arch/arm64/kernel/alternative.c')
| -rw-r--r-- | arch/arm64/kernel/alternative.c | 28 |
1 files changed, 24 insertions, 4 deletions
diff --git a/arch/arm64/kernel/alternative.c b/arch/arm64/kernel/alternative.c index d2ee1b21a10d..06d650f61da7 100644 --- a/arch/arm64/kernel/alternative.c +++ b/arch/arm64/kernel/alternative.c @@ -25,14 +25,13 @@ #include <asm/alternative.h> #include <asm/cpufeature.h> #include <asm/insn.h> +#include <asm/sections.h> #include <linux/stop_machine.h> #define __ALT_PTR(a,f) (u32 *)((void *)&(a)->f + (a)->f) #define ALT_ORIG_PTR(a) __ALT_PTR(a, orig_offset) #define ALT_REPL_PTR(a) __ALT_PTR(a, alt_offset) -extern struct alt_instr __alt_instructions[], __alt_instructions_end[]; - struct alt_region { struct alt_instr *begin; struct alt_instr *end; @@ -59,6 +58,8 @@ static bool branch_insn_requires_update(struct alt_instr *alt, unsigned long pc) BUG(); } +#define align_down(x, a) ((unsigned long)(x) & ~(((unsigned long)(a)) - 1)) + static u32 get_alt_insn(struct alt_instr *alt, u32 *insnptr, u32 *altinsnptr) { u32 insn; @@ -80,6 +81,25 @@ static u32 get_alt_insn(struct alt_instr *alt, u32 *insnptr, u32 *altinsnptr) offset = target - (unsigned long)insnptr; insn = aarch64_set_branch_offset(insn, offset); } + } else if (aarch64_insn_is_adrp(insn)) { + s32 orig_offset, new_offset; + unsigned long target; + + /* + * If we're replacing an adrp instruction, which uses PC-relative + * immediate addressing, adjust the offset to reflect the new + * PC. adrp operates on 4K aligned addresses. + */ + orig_offset = aarch64_insn_adrp_get_offset(insn); + target = align_down(altinsnptr, SZ_4K) + orig_offset; + new_offset = target - align_down(insnptr, SZ_4K); + insn = aarch64_insn_adrp_set_offset(insn, new_offset); + } else if (aarch64_insn_uses_literal(insn)) { + /* + * Disallow patching unhandled instructions using PC relative + * literal addresses + */ + BUG(); } return insn; @@ -124,8 +144,8 @@ static int __apply_alternatives_multi_stop(void *unused) { static int patched = 0; struct alt_region region = { - .begin = __alt_instructions, - .end = __alt_instructions_end, + .begin = (struct alt_instr *)__alt_instructions, + .end = (struct alt_instr *)__alt_instructions_end, }; /* We always have a CPU 0 at this point (__init) */ |