Messages in this thread Patch in this message | | | Date | Mon, 12 Feb 2018 11:45:03 -0600 | From | Josh Poimboeuf <> | Subject | [PATCH] x86/entry/64: Fix paranoid_entry() frame pointer warning |
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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 <fengguang.wu@intel.com> Fixes: f09d160992d1 ("x86/entry/64: Get rid of the ALLOC_PT_GPREGS_ON_STACK and SAVE_AND_CLEAR_REGS macros") Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> --- 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 cfbf43366731..1c54204207d8 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -1128,6 +1128,7 @@ 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 @@ -1141,7 +1142,7 @@ 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 -- 2.14.3
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