^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) /* SPDX-License-Identifier: GPL-2.0 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) #ifndef _ASM_X86_TEXT_PATCHING_H
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) #define _ASM_X86_TEXT_PATCHING_H
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) #include <linux/types.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) #include <linux/stddef.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) #include <asm/ptrace.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) struct paravirt_patch_site;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) #ifdef CONFIG_PARAVIRT
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) void apply_paravirt(struct paravirt_patch_site *start,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) struct paravirt_patch_site *end);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) #else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) static inline void apply_paravirt(struct paravirt_patch_site *start,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) struct paravirt_patch_site *end)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) {}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) #define __parainstructions NULL
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) #define __parainstructions_end NULL
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) * Currently, the max observed size in the kernel code is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) * JUMP_LABEL_NOP_SIZE/RELATIVEJUMP_SIZE, which are 5.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) * Raise it if needed.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) #define POKE_MAX_OPCODE_SIZE 5
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) extern void text_poke_early(void *addr, const void *opcode, size_t len);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) * Clear and restore the kernel write-protection flag on the local CPU.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) * Allows the kernel to edit read-only pages.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) * Side-effect: any interrupt handler running between save and restore will have
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) * the ability to write to read-only pages.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) * Warning:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) * Code patching in the UP case is safe if NMIs and MCE handlers are stopped and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) * no thread can be preempted in the instructions being modified (no iret to an
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) * invalid instruction possible) or if the instructions are changed from a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) * consistent state to another consistent state atomically.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) * On the local CPU you need to be protected against NMI or MCE handlers seeing
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) * an inconsistent instruction while you patch.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) extern void *text_poke(void *addr, const void *opcode, size_t len);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) extern void text_poke_sync(void);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) extern void *text_poke_kgdb(void *addr, const void *opcode, size_t len);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) extern int poke_int3_handler(struct pt_regs *regs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) extern void text_poke_bp(void *addr, const void *opcode, size_t len, const void *emulate);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) extern void text_poke_queue(void *addr, const void *opcode, size_t len, const void *emulate);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) extern void text_poke_finish(void);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) #define INT3_INSN_SIZE 1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) #define INT3_INSN_OPCODE 0xCC
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) #define RET_INSN_SIZE 1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) #define RET_INSN_OPCODE 0xC3
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) #define CALL_INSN_SIZE 5
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) #define CALL_INSN_OPCODE 0xE8
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) #define JMP32_INSN_SIZE 5
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) #define JMP32_INSN_OPCODE 0xE9
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) #define JMP8_INSN_SIZE 2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) #define JMP8_INSN_OPCODE 0xEB
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) #define DISP32_SIZE 4
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) static __always_inline int text_opcode_size(u8 opcode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) int size = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) #define __CASE(insn) \
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) case insn##_INSN_OPCODE: size = insn##_INSN_SIZE; break
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) switch(opcode) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) __CASE(INT3);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) __CASE(RET);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) __CASE(CALL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) __CASE(JMP32);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) __CASE(JMP8);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) #undef __CASE
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) return size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) union text_poke_insn {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) u8 text[POKE_MAX_OPCODE_SIZE];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) struct {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) u8 opcode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) s32 disp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) } __attribute__((packed));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) static __always_inline
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) void *text_gen_insn(u8 opcode, const void *addr, const void *dest)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) static union text_poke_insn insn; /* per instance */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) int size = text_opcode_size(opcode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) insn.opcode = opcode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) if (size > 1) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) insn.disp = (long)dest - (long)(addr + size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) if (size == 2) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) * Ensure that for JMP9 the displacement
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) * actually fits the signed byte.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) BUG_ON((insn.disp >> 31) != (insn.disp >> 7));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) return &insn.text;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) extern int after_bootmem;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) extern __ro_after_init struct mm_struct *poking_mm;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) extern __ro_after_init unsigned long poking_addr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) #ifndef CONFIG_UML_X86
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) static __always_inline
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) void int3_emulate_jmp(struct pt_regs *regs, unsigned long ip)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) regs->ip = ip;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) static __always_inline
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) void int3_emulate_push(struct pt_regs *regs, unsigned long val)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) * The int3 handler in entry_64.S adds a gap between the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) * stack where the break point happened, and the saving of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) * pt_regs. We can extend the original stack because of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) * this gap. See the idtentry macro's create_gap option.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) * Similarly entry_32.S will have a gap on the stack for (any) hardware
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) * exception and pt_regs; see FIXUP_FRAME.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) regs->sp -= sizeof(unsigned long);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) *(unsigned long *)regs->sp = val;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) static __always_inline
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) unsigned long int3_emulate_pop(struct pt_regs *regs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) unsigned long val = *(unsigned long *)regs->sp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) regs->sp += sizeof(unsigned long);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) return val;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) static __always_inline
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) void int3_emulate_call(struct pt_regs *regs, unsigned long func)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) int3_emulate_push(regs, regs->ip - INT3_INSN_SIZE + CALL_INSN_SIZE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) int3_emulate_jmp(regs, func);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) static __always_inline
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) void int3_emulate_ret(struct pt_regs *regs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) unsigned long ip = int3_emulate_pop(regs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) int3_emulate_jmp(regs, ip);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) #endif /* !CONFIG_UML_X86 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) #endif /* _ASM_X86_TEXT_PATCHING_H */
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
3 Commits
0 Branches
0 Tags