diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2019-05-08 14:30:48 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2019-06-25 10:23:45 +0200 |
| commit | a9b3c6998d4a7d53a787cf4d0fd4a4c11239e517 (patch) | |
| tree | f81102633a51f43551b6dbae1c7a33aa95d9c92c /arch/x86/entry/entry_32.S | |
| parent | 5e1246ff2d3707992e3bf3eaa45551f7fab97983 (diff) | |
x86/stackframe: Move ENCODE_FRAME_POINTER to asm/frame.h
In preparation for wider use, move the ENCODE_FRAME_POINTER macros to
a common header and provide inline asm versions.
These macros are used to encode a pt_regs frame for the unwinder; see
unwind_frame.c:decode_frame_pointer().
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/entry/entry_32.S')
| -rw-r--r-- | arch/x86/entry/entry_32.S | 16 |
1 files changed, 0 insertions, 16 deletions
diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index 7040d7e96250..ac2b3b4e09f7 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -246,22 +246,6 @@ .Lend_\@: .endm -/* - * This is a sneaky trick to help the unwinder find pt_regs on the stack. The - * frame pointer is replaced with an encoded pointer to pt_regs. The encoding - * is just clearing the MSB, which makes it an invalid stack address and is also - * a signal to the unwinder that it's a pt_regs pointer in disguise. - * - * NOTE: This macro must be used *after* SAVE_ALL because it corrupts the - * original rbp. - */ -.macro ENCODE_FRAME_POINTER -#ifdef CONFIG_FRAME_POINTER - mov %esp, %ebp - andl $0x7fffffff, %ebp -#endif -.endm - .macro RESTORE_INT_REGS popl %ebx popl %ecx |