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author | Josh Poimboeuf <jpoimboe@redhat.com> | 2016-10-10 15:24:01 -0500 |
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committer | Ingo Molnar <mingo@kernel.org> | 2016-10-11 10:35:45 +0200 |
commit | 2cc17fda94c5ee8c64c2fdc2ef981fc277e2e958 (patch) | |
tree | 8511b60eb9f6faa3e023e59b392dca690ae3ed1a /tools | |
parent | 597f03f9d133e9837d00965016170271d4f87dcf (diff) | |
download | linux-2cc17fda94c5ee8c64c2fdc2ef981fc277e2e958.tar.gz |
objtool: Support '-mtune=atom' stack frame setup instruction
Arnd reported that enabling CONFIG_MATOM results in a bunch of objtool false positive frame pointer warnings: arch/x86/events/intel/ds.o: warning: objtool: intel_pmu_pebs_del()+0x43: call without frame pointer save/setup security/keys/keyring.o: warning: objtool: keyring_read()+0x59: call without frame pointer save/setup kernel/signal.o: warning: objtool: __dequeue_signal()+0xd8: call without frame pointer save/setup ... objtool gets confused by the fact that the '-mtune=atom' GCC option sometimes uses 'lea (%rsp),%rbp' instead of 'mov %rsp,%rbp'. The instructions are effectively the same, but objtool doesn't know about the 'lea' variant. Fix the false warnings by adding support for 'lea (%rsp),%rbp' in the objtool decoder. Reported-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'tools')
-rw-r--r-- | tools/objtool/arch/x86/decode.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c index c0c0b265e88e..b63a31be1218 100644 --- a/tools/objtool/arch/x86/decode.c +++ b/tools/objtool/arch/x86/decode.c @@ -98,6 +98,15 @@ int arch_decode_instruction(struct elf *elf, struct section *sec, *type = INSN_FP_SETUP; break; + case 0x8d: + if (insn.rex_prefix.bytes && + insn.rex_prefix.bytes[0] == 0x48 && + insn.modrm.nbytes && insn.modrm.bytes[0] == 0x2c && + insn.sib.nbytes && insn.sib.bytes[0] == 0x24) + /* lea %(rsp), %rbp */ + *type = INSN_FP_SETUP; + break; + case 0x90: *type = INSN_NOP; break; |