diff options
| author | Nathan Chancellor <nathan@kernel.org> | 2021-04-13 17:08:04 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-04-28 12:08:41 +0200 |
| commit | b8ae95b946f3418a4f59cfb8229359d704f41707 (patch) | |
| tree | 6c07e4da5f0ce78f57afbaf1ab60166696f28083 /arch/arm64 | |
| parent | 013940a1e849b88c555e23cf9b41c7458038b97b (diff) | |
arm64: alternatives: Move length validation in alternative_{insn, endif}
commit 22315a2296f4c251fa92aec45fbbae37e9301b6c upstream.
After commit 2decad92f473 ("arm64: mte: Ensure TIF_MTE_ASYNC_FAULT is
set atomically"), LLVM's integrated assembler fails to build entry.S:
<instantiation>:5:7: error: expected assembly-time absolute expression
.org . - (664b-663b) + (662b-661b)
^
<instantiation>:6:7: error: expected assembly-time absolute expression
.org . - (662b-661b) + (664b-663b)
^
The root cause is LLVM's assembler has a one-pass design, meaning it
cannot figure out these instruction lengths when the .org directive is
outside of the subsection that they are in, which was changed by the
.arch_extension directive added in the above commit.
Apply the same fix from commit 966a0acce2fc ("arm64/alternatives: move
length validation inside the subsection") to the alternative_endif
macro, shuffling the .org directives so that the length validation
happen will always happen in the same subsections. alternative_insn has
not shown any issue yet but it appears that it could have the same issue
in the future so just preemptively change it.
Fixes: f7b93d42945c ("arm64/alternatives: use subsections for replacement sequences")
Cc: <stable@vger.kernel.org> # 5.8.x
Link: https://github.com/ClangBuiltLinux/linux/issues/1347
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20210414000803.662534-1-nathan@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/arm64')
| -rw-r--r-- | arch/arm64/include/asm/alternative.h | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/arm64/include/asm/alternative.h b/arch/arm64/include/asm/alternative.h index 3abb2dacb43f..ad986cfa592d 100644 --- a/arch/arm64/include/asm/alternative.h +++ b/arch/arm64/include/asm/alternative.h @@ -114,9 +114,9 @@ void apply_alternatives(void *start, size_t length); .popsection .subsection 1 663: \insn2 -664: .previous - .org . - (664b-663b) + (662b-661b) +664: .org . - (664b-663b) + (662b-661b) .org . - (662b-661b) + (664b-663b) + .previous .endif .endm @@ -186,11 +186,11 @@ void apply_alternatives(void *start, size_t length); */ .macro alternative_endif 664: + .org . - (664b-663b) + (662b-661b) + .org . - (662b-661b) + (664b-663b) .if .Lasm_alt_mode==0 .previous .endif - .org . - (664b-663b) + (662b-661b) - .org . - (662b-661b) + (664b-663b) .endm /* |