diff options
| -rw-r--r-- | arch/arm64/kernel/alternative.c | 31 |
1 files changed, 24 insertions, 7 deletions
diff --git a/arch/arm64/kernel/alternative.c b/arch/arm64/kernel/alternative.c index 414288a558c8..fdcdb15251a3 100644 --- a/arch/arm64/kernel/alternative.c +++ b/arch/arm64/kernel/alternative.c @@ -87,15 +87,32 @@ static u32 get_alt_insn(struct alt_instr *alt, __le32 *insnptr, __le32 *altinsnp 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); + + if (branch_insn_requires_update(alt, 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. + */ + new_offset = target - align_down(insnptr, SZ_4K); + insn = aarch64_insn_adrp_set_offset(insn, new_offset); + } + } else if (aarch64_insn_is_adr(insn)) { + s32 offset = aarch64_insn_adr_get_offset(insn); + unsigned long target; + + target = (unsigned long)altinsnptr + offset; + + if (branch_insn_requires_update(alt, target)) { + /* + * Disallow adr instructions for targets outside + * of our alt block. + */ + BUG(); + } } else if (aarch64_insn_uses_literal(insn)) { /* * Disallow patching unhandled instructions using PC relative |