blob: b7421780e4e92959689646cb425485c9deeabfc3 [file] [log] [blame]
/* SPDX-License-Identifier: GPL-2.0 */
#include <linux/types.h>
#include <linux/stddef.h>
#include <asm/ptrace.h>
struct paravirt_patch_site;
void apply_paravirt(struct paravirt_patch_site *start,
struct paravirt_patch_site *end);
static inline void apply_paravirt(struct paravirt_patch_site *start,
struct paravirt_patch_site *end)
#define __parainstructions NULL
#define __parainstructions_end NULL
* Currently, the max observed size in the kernel code is
* Raise it if needed.
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_sync(void);
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_queue(void *addr, const void *opcode, size_t len, const void *emulate);
extern void text_poke_finish(void);
#define INT3_INSN_SIZE 1
#define RET_INSN_SIZE 1
#define RET_INSN_OPCODE 0xC3
#define CALL_INSN_SIZE 5
#define JMP32_INSN_SIZE 5
#define JMP32_INSN_OPCODE 0xE9
#define JMP8_INSN_SIZE 2
#define DISP32_SIZE 4
static __always_inline int text_opcode_size(u8 opcode)
int size = 0;
#define __CASE(insn) \
case insn##_INSN_OPCODE: size = insn##_INSN_SIZE; break
switch(opcode) {
#undef __CASE
return size;
union text_poke_insn {
struct {
u8 opcode;
s32 disp;
} __attribute__((packed));
static __always_inline
void *text_gen_insn(u8 opcode, const void *addr, const void *dest)
static union text_poke_insn insn; /* per instance */
int size = text_opcode_size(opcode);
insn.opcode = opcode;
if (size > 1) {
insn.disp = (long)dest - (long)(addr + size);
if (size == 2) {
* Ensure that for JMP9 the displacement
* actually fits the signed byte.
BUG_ON((insn.disp >> 31) != (insn.disp >> 7));
return &insn.text;
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 __always_inline
void int3_emulate_jmp(struct pt_regs *regs, unsigned long ip)
regs->ip = ip;
static __always_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.
* Similarly entry_32.S will have a gap on the stack for (any) hardware
* exception and pt_regs; see FIXUP_FRAME.
regs->sp -= sizeof(unsigned long);
*(unsigned long *)regs->sp = val;
static __always_inline
unsigned long int3_emulate_pop(struct pt_regs *regs)
unsigned long val = *(unsigned long *)regs->sp;
regs->sp += sizeof(unsigned long);
return val;
static __always_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);
static __always_inline
void int3_emulate_ret(struct pt_regs *regs)
unsigned long ip = int3_emulate_pop(regs);
int3_emulate_jmp(regs, ip);
#endif /* !CONFIG_UML_X86 */
#endif /* _ASM_X86_TEXT_PATCHING_H */