diff options
| author | Christoph Muellner <christoph.muellner@theobroma-systems.com> | 2018-05-15 23:38:32 +0200 |
|---|---|---|
| committer | Christoph Muellner <christoph.muellner@theobroma-systems.com> | 2018-05-16 12:03:52 +0200 |
| commit | 9174f62bfbfe91215b9888272d8e8e0509f57ba2 (patch) | |
| tree | 9de86400f6a978cfae39873e7e479301a678c78a | |
| parent | d4e587ea8a236b03e1831b95c163ac6537c96d9d (diff) | |
arm64: alternatives: Add support for adr/adrp with offset in alt block.
When using adr or adrp with an offset within the alt block,
we can allow the instruction and we must not do any offset fixup.
Signed-off-by: Christoph Muellner <christoph.muellner@theobroma-systems.com>
| -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 5c4bce4ac381..a7a2371e7e99 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 |