1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_X86_TEXT_PATCHING_H
3 #define _ASM_X86_TEXT_PATCHING_H
5 #include <linux/types.h>
6 #include <linux/stddef.h>
7 #include <asm/ptrace.h>
9 struct paravirt_patch_site;
10 #ifdef CONFIG_PARAVIRT
11 void apply_paravirt(struct paravirt_patch_site *start,
12 struct paravirt_patch_site *end);
14 static inline void apply_paravirt(struct paravirt_patch_site *start,
15 struct paravirt_patch_site *end)
17 #define __parainstructions NULL
18 #define __parainstructions_end NULL
21 extern void text_poke_early(void *addr, const void *opcode, size_t len);
24 * Clear and restore the kernel write-protection flag on the local CPU.
25 * Allows the kernel to edit read-only pages.
26 * Side-effect: any interrupt handler running between save and restore will have
27 * the ability to write to read-only pages.
30 * Code patching in the UP case is safe if NMIs and MCE handlers are stopped and
31 * no thread can be preempted in the instructions being modified (no iret to an
32 * invalid instruction possible) or if the instructions are changed from a
33 * consistent state to another consistent state atomically.
34 * On the local CPU you need to be protected again NMI or MCE handlers seeing an
35 * inconsistent instruction while you patch.
37 extern void *text_poke(void *addr, const void *opcode, size_t len);
38 extern void *text_poke_kgdb(void *addr, const void *opcode, size_t len);
39 extern int poke_int3_handler(struct pt_regs *regs);
40 extern void text_poke_bp(void *addr, const void *opcode, size_t len, void *handler);
41 extern int after_bootmem;
42 extern __ro_after_init struct mm_struct *poking_mm;
43 extern __ro_after_init unsigned long poking_addr;
45 #ifndef CONFIG_UML_X86
46 static inline void int3_emulate_jmp(struct pt_regs *regs, unsigned long ip)
51 #define INT3_INSN_SIZE 1
52 #define CALL_INSN_SIZE 5
55 static inline void int3_emulate_push(struct pt_regs *regs, unsigned long val)
58 * The int3 handler in entry_64.S adds a gap between the
59 * stack where the break point happened, and the saving of
60 * pt_regs. We can extend the original stack because of
61 * this gap. See the idtentry macro's create_gap option.
63 regs->sp -= sizeof(unsigned long);
64 *(unsigned long *)regs->sp = val;
67 static inline void int3_emulate_call(struct pt_regs *regs, unsigned long func)
69 int3_emulate_push(regs, regs->ip - INT3_INSN_SIZE + CALL_INSN_SIZE);
70 int3_emulate_jmp(regs, func);
72 #endif /* CONFIG_X86_64 */
73 #endif /* !CONFIG_UML_X86 */
75 #endif /* _ASM_X86_TEXT_PATCHING_H */