From bdcf05c64a64743f512f12b17d4f9d8b14d2ad31 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Mon, 12 Feb 2018 11:45:03 -0600 Subject: [PATCH] x86/entry/64: Fix paranoid_entry() frame pointer warning commit b3ccefaed922529e6a67de7b30af5aa38c76ace9 upstream. With the following commit: f09d160992d1 ("x86/entry/64: Get rid of the ALLOC_PT_GPREGS_ON_STACK and SAVE_AND_CLEAR_REGS macros") ... one of my suggested improvements triggered a frame pointer warning: arch/x86/entry/entry_64.o: warning: objtool: paranoid_entry()+0x11: call without frame pointer save/setup The warning is correct for the build-time code, but it's actually not relevant at runtime because of paravirt patching. The paravirt swapgs call gets replaced with either a SWAPGS instruction or NOPs at runtime. Go back to the previous behavior by removing the ELF function annotation for paranoid_entry() and adding an unwind hint, which effectively silences the warning. Reported-by: kbuild test robot Signed-off-by: Josh Poimboeuf Cc: Dominik Brodowski Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: kbuild-all@01.org Cc: tipbuild@zytor.com Fixes: f09d160992d1 ("x86/entry/64: Get rid of the ALLOC_PT_GPREGS_ON_STACK and SAVE_AND_CLEAR_REGS macros") Link: http://lkml.kernel.org/r/20180212174503.5acbymg5z6p32snu@treble Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- arch/x86/entry/entry_64.S | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 8a3280b..c5ef704 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -1122,6 +1122,7 @@ idtentry machine_check do_mce has_error_code=0 paranoid=1 * Return: ebx=0: need swapgs on exit, ebx=1: otherwise */ ENTRY(paranoid_entry) + UNWIND_HINT_FUNC cld movl $1, %ebx movl $MSR_GS_BASE, %ecx @@ -1135,7 +1136,7 @@ ENTRY(paranoid_entry) SAVE_AND_SWITCH_TO_KERNEL_CR3 scratch_reg=%rax save_reg=%r14 ret -ENDPROC(paranoid_entry) +END(paranoid_entry) /* * "Paranoid" exit path from exception stack. This is invoked -- 2.7.4