diff options
Diffstat (limited to 'arch/x86/include/asm/frame.h')
| -rw-r--r-- | arch/x86/include/asm/frame.h | 127 |
1 files changed, 107 insertions, 20 deletions
diff --git a/arch/x86/include/asm/frame.h b/arch/x86/include/asm/frame.h index 3b629f47eb65..0ab65073c1cc 100644 --- a/arch/x86/include/asm/frame.h +++ b/arch/x86/include/asm/frame.h @@ -1,26 +1,113 @@ -#ifdef __ASSEMBLY__ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_X86_FRAME_H +#define _ASM_X86_FRAME_H #include <asm/asm.h> -#include <asm/dwarf2.h> -/* The annotation hides the frame from the unwinder and makes it look - like a ordinary ebp save/restore. This avoids some special cases for - frame pointer later */ +/* + * 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 - .macro FRAME - __ASM_SIZE(push,_cfi) %__ASM_REG(bp) - CFI_REL_OFFSET __ASM_REG(bp), 0 - __ASM_SIZE(mov) %__ASM_REG(sp), %__ASM_REG(bp) - .endm - .macro ENDFRAME - __ASM_SIZE(pop,_cfi) %__ASM_REG(bp) - CFI_RESTORE __ASM_REG(bp) - .endm -#else - .macro FRAME - .endm - .macro ENDFRAME - .endm + +#ifdef __ASSEMBLER__ + +.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 /* !__ASSEMBLER__ */ + +#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 /* __ASSEMBLER__ */ + +#define FRAME_OFFSET __ASM_SEL(4, 8) + +#else /* !CONFIG_FRAME_POINTER */ + +#ifdef __ASSEMBLER__ + +.macro ENCODE_FRAME_POINTER ptregs_offset=0 +.endm + +#else /* !__ASSEMBLER__ */ + +#define ENCODE_FRAME_POINTER + +static inline unsigned long encode_frame_pointer(struct pt_regs *regs) +{ + return 0; +} + #endif -#endif /* __ASSEMBLY__ */ +#define FRAME_BEGIN +#define FRAME_END +#define FRAME_OFFSET 0 + +#endif /* CONFIG_FRAME_POINTER */ + +#endif /* _ASM_X86_FRAME_H */ |