Messages in this thread Patch in this message | | | From | Josh Poimboeuf <> | Subject | [PATCH v2 04/11] x86/entry/64: Fix unwind hints in __switch_to_asm() | Date | Sat, 25 Apr 2020 05:03:03 -0500 |
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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") Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Reviewed-by: Miroslav Benes <mbenes@suse.cz> --- 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. -- 2.21.1
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