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| author | Josh Poimboeuf <jpoimboe@redhat.com> | 2017-09-27 10:36:38 -0500 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-09-28 07:25:54 +0200 |
| commit | 607a4029d439cdfa258aff5da32bb9cd6ed1a66d (patch) | |
| tree | f370578574533527b649479db1703f0a82db99c3 /tools | |
| parent | da541b20021c781f8b65492eeaee824e729599eb (diff) | |
| download | lwn-607a4029d439cdfa258aff5da32bb9cd6ed1a66d.tar.gz lwn-607a4029d439cdfa258aff5da32bb9cd6ed1a66d.zip | |
objtool: Support unoptimized frame pointer setup
Arnd Bergmann reported a bunch of warnings like:
crypto/jitterentropy.o: warning: objtool: jent_fold_time()+0x3b: call without frame pointer save/setup
crypto/jitterentropy.o: warning: objtool: jent_stuck()+0x1d: call without frame pointer save/setup
crypto/jitterentropy.o: warning: objtool: jent_unbiased_bit()+0x15: call without frame pointer save/setup
crypto/jitterentropy.o: warning: objtool: jent_read_entropy()+0x32: call without frame pointer save/setup
crypto/jitterentropy.o: warning: objtool: jent_entropy_collector_free()+0x19: call without frame pointer save/setup
and
arch/x86/events/core.o: warning: objtool: collect_events uses BP as a scratch register
arch/x86/events/core.o: warning: objtool: events_ht_sysfs_show()+0x22: call without frame pointer save/setup
With certain rare configurations, GCC sometimes sets up the frame
pointer with:
lea (%rsp),%rbp
instead of:
mov %rsp,%rbp
The instructions are equivalent, so treat the former like the latter.
Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/a468af8b28a69b83fffc6d7668be9b6fcc873699.1506526584.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/objtool/arch/x86/decode.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c index 0f22768c0d4d..34a579f806e3 100644 --- a/tools/objtool/arch/x86/decode.c +++ b/tools/objtool/arch/x86/decode.c @@ -284,11 +284,16 @@ int arch_decode_instruction(struct elf *elf, struct section *sec, case 0x8d: if (sib == 0x24 && rex_w && !rex_b && !rex_x) { - /* lea disp(%rsp), reg */ *type = INSN_STACK; - op->src.type = OP_SRC_ADD; + if (!insn.displacement.value) { + /* lea (%rsp), reg */ + op->src.type = OP_SRC_REG; + } else { + /* lea disp(%rsp), reg */ + op->src.type = OP_SRC_ADD; + op->src.offset = insn.displacement.value; + } op->src.reg = CFI_SP; - op->src.offset = insn.displacement.value; op->dest.type = OP_DEST_REG; op->dest.reg = op_to_cfi_reg[modrm_reg][rex_r]; |