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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_TEXT_PATCHING_H
#define _ASM_X86_TEXT_PATCHING_H
#include <linux/types.h>
#include <linux/stddef.h>
#include <asm/ptrace.h>
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
/*
* Currently, the max observed size in the kernel code is
* JUMP_LABEL_NOP_SIZE/RELATIVEJUMP_SIZE, which are 5.
* Raise it if needed.
*/
#define POKE_MAX_OPCODE_SIZE 5
struct text_poke_loc {
void *addr;
int len;
s32 rel32;
u8 opcode;
const u8 text[POKE_MAX_OPCODE_SIZE];
};
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 against NMI or MCE handlers seeing
* an inconsistent instruction while you patch.
*/
extern void *text_poke(void *addr, const void *opcode, size_t len);
extern void *text_poke_kgdb(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, const void *emulate);
extern void text_poke_bp_batch(struct text_poke_loc *tp, unsigned int nr_entries);
extern void text_poke_loc_init(struct text_poke_loc *tp, void *addr,
const void *opcode, size_t len, const void *emulate);
extern int after_bootmem;
extern __ro_after_init struct mm_struct *poking_mm;
extern __ro_after_init unsigned long poking_addr;
#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 INT3_INSN_OPCODE 0xCC
#define CALL_INSN_SIZE 5
#define CALL_INSN_OPCODE 0xE8
#define JMP32_INSN_SIZE 5
#define JMP32_INSN_OPCODE 0xE9
#define JMP8_INSN_SIZE 2
#define JMP8_INSN_OPCODE 0xEB
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_UML_X86 */
#endif /* _ASM_X86_TEXT_PATCHING_H */
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