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Diffstat (limited to 'arch/x86/include/asm/frame.h')
| -rw-r--r-- | arch/x86/include/asm/frame.h | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/arch/x86/include/asm/frame.h b/arch/x86/include/asm/frame.h new file mode 100644 index 000000000..fb42659f6 --- /dev/null +++ b/arch/x86/include/asm/frame.h @@ -0,0 +1,113 @@ +/* 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 */ |