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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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