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a9b3c6998d
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>
94 lines
2.2 KiB
C
94 lines
2.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_X86_FRAME_H
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#define _ASM_X86_FRAME_H
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#include <asm/asm.h>
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/*
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* These are stack frame creation macros. They should be used by every
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* callable non-leaf asm function to make kernel stack traces more reliable.
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*/
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#ifdef CONFIG_FRAME_POINTER
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#ifdef __ASSEMBLY__
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.macro FRAME_BEGIN
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push %_ASM_BP
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_ASM_MOV %_ASM_SP, %_ASM_BP
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.endm
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.macro FRAME_END
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pop %_ASM_BP
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.endm
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#ifdef CONFIG_X86_64
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/*
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* This is a sneaky trick to help the unwinder find pt_regs on the stack. The
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* frame pointer is replaced with an encoded pointer to pt_regs. The encoding
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* is just setting the LSB, which makes it an invalid stack address and is also
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* a signal to the unwinder that it's a pt_regs pointer in disguise.
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*
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* NOTE: This macro must be used *after* PUSH_AND_CLEAR_REGS because it corrupts
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* the original rbp.
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*/
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.macro ENCODE_FRAME_POINTER ptregs_offset=0
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leaq 1+\ptregs_offset(%rsp), %rbp
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.endm
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#else /* !CONFIG_X86_64 */
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/*
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* This is a sneaky trick to help the unwinder find pt_regs on the stack. The
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* frame pointer is replaced with an encoded pointer to pt_regs. The encoding
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* is just clearing the MSB, which makes it an invalid stack address and is also
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* a signal to the unwinder that it's a pt_regs pointer in disguise.
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*
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* NOTE: This macro must be used *after* SAVE_ALL because it corrupts the
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* original ebp.
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*/
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.macro ENCODE_FRAME_POINTER
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mov %esp, %ebp
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andl $0x7fffffff, %ebp
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.endm
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#endif /* CONFIG_X86_64 */
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#else /* !__ASSEMBLY__ */
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#define FRAME_BEGIN \
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"push %" _ASM_BP "\n" \
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_ASM_MOV "%" _ASM_SP ", %" _ASM_BP "\n"
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#define FRAME_END "pop %" _ASM_BP "\n"
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#ifdef CONFIG_X86_64
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#define ENCODE_FRAME_POINTER \
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"lea 1(%rsp), %rbp\n\t"
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#else /* !CONFIG_X86_64 */
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#define ENCODE_FRAME_POINTER \
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"movl %esp, %ebp\n\t" \
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"andl $0x7fffffff, %ebp\n\t"
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#endif /* CONFIG_X86_64 */
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#endif /* __ASSEMBLY__ */
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#define FRAME_OFFSET __ASM_SEL(4, 8)
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#else /* !CONFIG_FRAME_POINTER */
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#ifdef __ASSEMBLY__
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.macro ENCODE_FRAME_POINTER ptregs_offset=0
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.endm
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#else /* !__ASSEMBLY */
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#define ENCODE_FRAME_POINTER
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#endif
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#define FRAME_BEGIN
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#define FRAME_END
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#define FRAME_OFFSET 0
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#endif /* CONFIG_FRAME_POINTER */
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#endif /* _ASM_X86_FRAME_H */
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