Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_X86_TEXT_PATCHING_H
3#define _ASM_X86_TEXT_PATCHING_H
4
5#include <linux/types.h>
6#include <linux/stddef.h>
7#include <asm/ptrace.h>
8
9struct paravirt_patch_site;
10#ifdef CONFIG_PARAVIRT
11void apply_paravirt(struct paravirt_patch_site *start,
12 struct paravirt_patch_site *end);
13#else
14static inline void apply_paravirt(struct paravirt_patch_site *start,
15 struct paravirt_patch_site *end)
16{}
17#define __parainstructions NULL
18#define __parainstructions_end NULL
19#endif
20
21/*
22 * Currently, the max observed size in the kernel code is
23 * JUMP_LABEL_NOP_SIZE/RELATIVEJUMP_SIZE, which are 5.
24 * Raise it if needed.
25 */
26#define POKE_MAX_OPCODE_SIZE 5
27
28struct text_poke_loc {
29 void *detour;
30 void *addr;
31 size_t len;
32 const char opcode[POKE_MAX_OPCODE_SIZE];
33};
34
35extern void text_poke_early(void *addr, const void *opcode, size_t len);
36
37/*
38 * Clear and restore the kernel write-protection flag on the local CPU.
39 * Allows the kernel to edit read-only pages.
40 * Side-effect: any interrupt handler running between save and restore will have
41 * the ability to write to read-only pages.
42 *
43 * Warning:
44 * Code patching in the UP case is safe if NMIs and MCE handlers are stopped and
45 * no thread can be preempted in the instructions being modified (no iret to an
46 * invalid instruction possible) or if the instructions are changed from a
47 * consistent state to another consistent state atomically.
48 * On the local CPU you need to be protected against NMI or MCE handlers seeing
49 * an inconsistent instruction while you patch.
50 */
51extern void *text_poke(void *addr, const void *opcode, size_t len);
52extern void *text_poke_kgdb(void *addr, const void *opcode, size_t len);
53extern int poke_int3_handler(struct pt_regs *regs);
54extern void text_poke_bp(void *addr, const void *opcode, size_t len, void *handler);
55extern void text_poke_bp_batch(struct text_poke_loc *tp, unsigned int nr_entries);
56extern int after_bootmem;
57extern __ro_after_init struct mm_struct *poking_mm;
58extern __ro_after_init unsigned long poking_addr;
59
60#ifndef CONFIG_UML_X86
61static inline void int3_emulate_jmp(struct pt_regs *regs, unsigned long ip)
62{
63 regs->ip = ip;
64}
65
66#define INT3_INSN_SIZE 1
67#define CALL_INSN_SIZE 5
68
69static inline void int3_emulate_push(struct pt_regs *regs, unsigned long val)
70{
71 /*
72 * The int3 handler in entry_64.S adds a gap between the
73 * stack where the break point happened, and the saving of
74 * pt_regs. We can extend the original stack because of
75 * this gap. See the idtentry macro's create_gap option.
76 */
77 regs->sp -= sizeof(unsigned long);
78 *(unsigned long *)regs->sp = val;
79}
80
81static inline void int3_emulate_call(struct pt_regs *regs, unsigned long func)
82{
83 int3_emulate_push(regs, regs->ip - INT3_INSN_SIZE + CALL_INSN_SIZE);
84 int3_emulate_jmp(regs, func);
85}
86#endif /* !CONFIG_UML_X86 */
87
88#endif /* _ASM_X86_TEXT_PATCHING_H */