From 96c64806b4bf35f5edb465cafa6cec490e424a30 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Sat, 25 Apr 2020 05:03:03 -0500 Subject: [PATCH] x86/entry/64: Fix unwind hints in __switch_to_asm() UNWIND_HINT_FUNC has some limitations: specifically, it doesn't reset all the registers to undefined. This causes objtool to get confused about the RBP push in __switch_to_asm(), resulting in bad ORC data. While __switch_to_asm() does do some stack magic, it's otherwise a normal callable-from-C function, so just annotate it as a function, which makes objtool happy and allows it to produces the correct hints automatically. Fixes: 8c1f75587a18 ("x86/entry/64: Add unwind hint annotations") Reviewed-by: Miroslav Benes Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Cc: Andy Lutomirski Cc: Dave Jones Cc: Jann Horn Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vince Weaver Link: https://lore.kernel.org/r/03d0411920d10f7418f2e909210d8e9a3b2ab081.1587808742.git.jpoimboe@redhat.com --- arch/x86/entry/entry_64.S | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 6b0d679efd6b..34a588950fe1 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -279,8 +279,7 @@ SYM_CODE_END(entry_SYSCALL_64) * %rdi: prev task * %rsi: next task */ -SYM_CODE_START(__switch_to_asm) - UNWIND_HINT_FUNC +SYM_FUNC_START(__switch_to_asm) /* * Save callee-saved registers * This must match the order in inactive_task_frame @@ -321,7 +320,7 @@ SYM_CODE_START(__switch_to_asm) popq %rbp jmp __switch_to -SYM_CODE_END(__switch_to_asm) +SYM_FUNC_END(__switch_to_asm) /* * A newly forked process directly context switches into this address. -- 2.34.1