On Thu, May 17, 2018 at 08:49:34AM -0500, Josh Poimboeuf wrote: > With the following commit: > > 51bad67ffbce ("x86/asm: Pad assembly functions with INT3 instructions") > > ... asm function alignments are padded with INT3, so it's no longer safe > to fall through to an aligned function. Make sure we catch any such > cases with objtool. > > Note this only adds checking for 64-bit, since objtool doesn't support > x86-32. > > Suggested-by: Thomas Gleixner > Suggested-by: Linus Torvalds > Signed-off-by: Josh Poimboeuf > --- > arch/x86/kernel/head_64.S | 2 -- > tools/objtool/arch.h | 3 ++- > tools/objtool/arch/x86/decode.c | 2 +- > tools/objtool/check.c | 11 ++++++++++- > 4 files changed, 13 insertions(+), 5 deletions(-) > > diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S > index 8344dd2f310a..3ed8cec6e765 100644 > --- a/arch/x86/kernel/head_64.S > +++ b/arch/x86/kernel/head_64.S > @@ -285,11 +285,9 @@ ENTRY(early_idt_handler_array) > .endif > pushq $i # 72(%rsp) Vector number > jmp early_idt_handler_common > - UNWIND_HINT_IRET_REGS > i = i + 1 > .fill early_idt_handler_array + i*EARLY_IDT_HANDLER_SIZE - ., 1, 0xcc > .endr > - UNWIND_HINT_IRET_REGS offset=16 > END(early_idt_handler_array) > > early_idt_handler_common: As noted on IRC; I got slightly confused what this was about. Other than that: Acked-by: Peter Zijlstra (Intel)