Messages in this thread Patch in this message | | | Date | Sun, 26 Apr 2020 06:47:42 -0000 | From | "tip-bot2 for Josh Poimboeuf" <> | Subject | [tip: x86/urgent] x86/entry/64: Fix unwind hints in __switch_to_asm() |
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The following commit has been merged into the x86/urgent branch of tip:
Commit-ID: 96c64806b4bf35f5edb465cafa6cec490e424a30 Gitweb: https://git.kernel.org/tip/96c64806b4bf35f5edb465cafa6cec490e424a30 Author: Josh Poimboeuf <jpoimboe@redhat.com> AuthorDate: Sat, 25 Apr 2020 05:03:03 -05:00 Committer: Ingo Molnar <mingo@kernel.org> CommitterDate: Sat, 25 Apr 2020 12:22:28 +02:00
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 <mbenes@suse.cz> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Dave Jones <dsj@fb.com> Cc: Jann Horn <jannh@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> 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 6b0d679..34a5889 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.
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