/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _ASM_X86_TEXT_PATCHING_H #define _ASM_X86_TEXT_PATCHING_H #include #include #include struct paravirt_patch_site; #ifdef CONFIG_PARAVIRT void apply_paravirt(struct paravirt_patch_site *start, struct paravirt_patch_site *end); #else static inline void apply_paravirt(struct paravirt_patch_site *start, struct paravirt_patch_site *end) {} #define __parainstructions NULL #define __parainstructions_end NULL #endif extern void *text_poke_early(void *addr, const void *opcode, size_t len); /* * Clear and restore the kernel write-protection flag on the local CPU. * Allows the kernel to edit read-only pages. * Side-effect: any interrupt handler running between save and restore will have * the ability to write to read-only pages. * * Warning: * Code patching in the UP case is safe if NMIs and MCE handlers are stopped and * no thread can be preempted in the instructions being modified (no iret to an * invalid instruction possible) or if the instructions are changed from a * consistent state to another consistent state atomically. * On the local CPU you need to be protected again NMI or MCE handlers seeing an * inconsistent instruction while you patch. */ extern void *text_poke(void *addr, const void *opcode, size_t len); extern int poke_int3_handler(struct pt_regs *regs); extern void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler); #ifndef CONFIG_UML_X86 static inline void int3_emulate_jmp(struct pt_regs *regs, unsigned long ip) { regs->ip = ip; } #define INT3_INSN_SIZE 1 #define CALL_INSN_SIZE 5 #ifdef CONFIG_X86_64 static inline void int3_emulate_push(struct pt_regs *regs, unsigned long val) { /* * The int3 handler in entry_64.S adds a gap between the * stack where the break point happened, and the saving of * pt_regs. We can extend the original stack because of * this gap. See the idtentry macro's create_gap option. */ regs->sp -= sizeof(unsigned long); *(unsigned long *)regs->sp = val; } static inline void int3_emulate_call(struct pt_regs *regs, unsigned long func) { int3_emulate_push(regs, regs->ip - INT3_INSN_SIZE + CALL_INSN_SIZE); int3_emulate_jmp(regs, func); } #endif /* CONFIG_X86_64 */ #endif /* !CONFIG_UML_X86 */ #endif /* _ASM_X86_TEXT_PATCHING_H */