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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_FRAME_H
#define _ASM_X86_FRAME_H
#include <asm/asm.h>
/*
* These are stack frame creation macros. They should be used by every
* callable non-leaf asm function to make kernel stack traces more reliable.
*/
#ifdef CONFIG_FRAME_POINTER
#ifdef __ASSEMBLY__
.macro FRAME_BEGIN
push %_ASM_BP
_ASM_MOV %_ASM_SP, %_ASM_BP
.endm
.macro FRAME_END
pop %_ASM_BP
.endm
#ifdef CONFIG_X86_64
/*
* 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 setting the LSB, 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* PUSH_AND_CLEAR_REGS because it corrupts
* the original rbp.
*/
.macro ENCODE_FRAME_POINTER ptregs_offset=0
leaq 1+\ptregs_offset(%rsp), %rbp
.endm
#else /* !CONFIG_X86_64 */
/*
* 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 ebp.
*/
.macro ENCODE_FRAME_POINTER
mov %esp, %ebp
andl $0x7fffffff, %ebp
.endm
#endif /* CONFIG_X86_64 */
#else /* !__ASSEMBLY__ */
#define FRAME_BEGIN \
"push %" _ASM_BP "\n" \
_ASM_MOV "%" _ASM_SP ", %" _ASM_BP "\n"
#define FRAME_END "pop %" _ASM_BP "\n"
#ifdef CONFIG_X86_64
#define ENCODE_FRAME_POINTER \
"lea 1(%rsp), %rbp\n\t"
static inline unsigned long encode_frame_pointer(struct pt_regs *regs)
{
return (unsigned long)regs + 1;
}
#else /* !CONFIG_X86_64 */
#define ENCODE_FRAME_POINTER \
"movl %esp, %ebp\n\t" \
"andl $0x7fffffff, %ebp\n\t"
static inline unsigned long encode_frame_pointer(struct pt_regs *regs)
{
return (unsigned long)regs & 0x7fffffff;
}
#endif /* CONFIG_X86_64 */
#endif /* __ASSEMBLY__ */
#define FRAME_OFFSET __ASM_SEL(4, 8)
#else /* !CONFIG_FRAME_POINTER */
#ifdef __ASSEMBLY__
.macro ENCODE_FRAME_POINTER ptregs_offset=0
.endm
#else /* !__ASSEMBLY */
#define ENCODE_FRAME_POINTER
static inline unsigned long encode_frame_pointer(struct pt_regs *regs)
{
return 0;
}
#endif
#define FRAME_BEGIN
#define FRAME_END
#define FRAME_OFFSET 0
#endif /* CONFIG_FRAME_POINTER */
#endif /* _ASM_X86_FRAME_H */
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