diff options
| author | Josh Poimboeuf <jpoimboe@redhat.com> | 2018-03-22 19:00:37 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2018-03-27 08:21:29 +0200 |
| commit | 3c1f05835cbf9fdfe60b81c718d82ceb94b6c55e (patch) | |
| tree | b554c520676ffc32a1c8c2dc3e77f200b6a27816 /tools/objtool | |
| parent | x86/entry/64: Don't use IST entry for #BP stack (diff) | |
| download | linux-3c1f05835cbf9fdfe60b81c718d82ceb94b6c55e.tar.xz linux-3c1f05835cbf9fdfe60b81c718d82ceb94b6c55e.zip | |
objtool: Add Clang support
Since the ORC unwinder was made the default on x86_64, Clang-built
defconfig kernels have triggered some new objtool warnings:
drivers/gpu/drm/i915/i915_gpu_error.o: warning: objtool: i915_error_printf()+0x6c: return with modified stack frame
drivers/gpu/drm/i915/intel_display.o: warning: objtool: pipe_config_err()+0xa6: return with modified stack frame
The problem is that objtool has never seen clang-built binaries before.
Shockingly enough, objtool is apparently able to follow the code flow
mostly fine, except for one instruction sequence. Instead of a LEAVE
instruction, clang restores RSP and RBP the long way:
67c: 48 89 ec mov %rbp,%rsp
67f: 5d pop %rbp
Teach objtool about this new code sequence.
Reported-and-test-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthias Kaehlcke <mka@chromium.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/fce88ce81c356eedcae7f00ed349cfaddb3363cc.1521741586.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'tools/objtool')
| -rw-r--r-- | tools/objtool/check.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 92b6a2c21631..5409f6f6c48d 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1386,6 +1386,17 @@ static int update_insn_state(struct instruction *insn, struct insn_state *state) state->vals[op->dest.reg].offset = -state->stack_size; } + else if (op->src.reg == CFI_BP && op->dest.reg == CFI_SP && + cfa->base == CFI_BP) { + + /* + * mov %rbp, %rsp + * + * Restore the original stack pointer (Clang). + */ + state->stack_size = -state->regs[CFI_BP].offset; + } + else if (op->dest.reg == cfa->base) { /* mov %reg, %rsp */ |