frame.h (2555B)
1/* SPDX-License-Identifier: GPL-2.0 */ 2#ifndef _ASM_X86_FRAME_H 3#define _ASM_X86_FRAME_H 4 5#include <asm/asm.h> 6 7/* 8 * These are stack frame creation macros. They should be used by every 9 * callable non-leaf asm function to make kernel stack traces more reliable. 10 */ 11 12#ifdef CONFIG_FRAME_POINTER 13 14#ifdef __ASSEMBLY__ 15 16.macro FRAME_BEGIN 17 push %_ASM_BP 18 _ASM_MOV %_ASM_SP, %_ASM_BP 19.endm 20 21.macro FRAME_END 22 pop %_ASM_BP 23.endm 24 25#ifdef CONFIG_X86_64 26/* 27 * This is a sneaky trick to help the unwinder find pt_regs on the stack. The 28 * frame pointer is replaced with an encoded pointer to pt_regs. The encoding 29 * is just setting the LSB, which makes it an invalid stack address and is also 30 * a signal to the unwinder that it's a pt_regs pointer in disguise. 31 * 32 * NOTE: This macro must be used *after* PUSH_AND_CLEAR_REGS because it corrupts 33 * the original rbp. 34 */ 35.macro ENCODE_FRAME_POINTER ptregs_offset=0 36 leaq 1+\ptregs_offset(%rsp), %rbp 37.endm 38#else /* !CONFIG_X86_64 */ 39/* 40 * This is a sneaky trick to help the unwinder find pt_regs on the stack. The 41 * frame pointer is replaced with an encoded pointer to pt_regs. The encoding 42 * is just clearing the MSB, which makes it an invalid stack address and is also 43 * a signal to the unwinder that it's a pt_regs pointer in disguise. 44 * 45 * NOTE: This macro must be used *after* SAVE_ALL because it corrupts the 46 * original ebp. 47 */ 48.macro ENCODE_FRAME_POINTER 49 mov %esp, %ebp 50 andl $0x7fffffff, %ebp 51.endm 52#endif /* CONFIG_X86_64 */ 53 54#else /* !__ASSEMBLY__ */ 55 56#define FRAME_BEGIN \ 57 "push %" _ASM_BP "\n" \ 58 _ASM_MOV "%" _ASM_SP ", %" _ASM_BP "\n" 59 60#define FRAME_END "pop %" _ASM_BP "\n" 61 62#ifdef CONFIG_X86_64 63 64#define ENCODE_FRAME_POINTER \ 65 "lea 1(%rsp), %rbp\n\t" 66 67static inline unsigned long encode_frame_pointer(struct pt_regs *regs) 68{ 69 return (unsigned long)regs + 1; 70} 71 72#else /* !CONFIG_X86_64 */ 73 74#define ENCODE_FRAME_POINTER \ 75 "movl %esp, %ebp\n\t" \ 76 "andl $0x7fffffff, %ebp\n\t" 77 78static inline unsigned long encode_frame_pointer(struct pt_regs *regs) 79{ 80 return (unsigned long)regs & 0x7fffffff; 81} 82 83#endif /* CONFIG_X86_64 */ 84 85#endif /* __ASSEMBLY__ */ 86 87#define FRAME_OFFSET __ASM_SEL(4, 8) 88 89#else /* !CONFIG_FRAME_POINTER */ 90 91#ifdef __ASSEMBLY__ 92 93.macro ENCODE_FRAME_POINTER ptregs_offset=0 94.endm 95 96#else /* !__ASSEMBLY */ 97 98#define ENCODE_FRAME_POINTER 99 100static inline unsigned long encode_frame_pointer(struct pt_regs *regs) 101{ 102 return 0; 103} 104 105#endif 106 107#define FRAME_BEGIN 108#define FRAME_END 109#define FRAME_OFFSET 0 110 111#endif /* CONFIG_FRAME_POINTER */ 112 113#endif /* _ASM_X86_FRAME_H */