Commit 254d2c04 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

x86/alternative: Add text_opcode_size() 



Introduce a common helper to map *_INSN_OPCODE to *_INSN_SIZE.

Tested-by: default avatarAlexei Starovoitov <ast@kernel.org>
Tested-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: default avatarAlexei Starovoitov <ast@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20191111132457.875666061@infradead.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent c12af440

arch/x86/include/asm/text-patching.h

+31 −12
Original line number Diff line number Diff line
@@ -49,18 +49,6 @@ extern void text_poke_bp(void *addr, const void *opcode, size_t len, const void 
extern void text_poke_queue(void *addr, const void *opcode, size_t len, const void *emulate);

extern void text_poke_finish(void);



extern void *text_gen_insn(u8 opcode, const void *addr, const void *dest);



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
@@ -73,6 +61,37 @@ static inline void int3_emulate_jmp(struct pt_regs *regs, unsigned long ip) 
#define JMP8_INSN_SIZE		2

#define JMP8_INSN_OPCODE	0xEB



static inline int text_opcode_size(u8 opcode)

{

	int size = 0;



#define __CASE(insn)	\

	case insn##_INSN_OPCODE: size = insn##_INSN_SIZE; break



	switch(opcode) {

	__CASE(INT3);

	__CASE(CALL);

	__CASE(JMP32);

	__CASE(JMP8);

	}



#undef __CASE



	return size;

}



extern void *text_gen_insn(u8 opcode, const void *addr, const void *dest);



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;

}



static inline void int3_emulate_push(struct pt_regs *regs, unsigned long val)

{

	/*

arch/x86/kernel/alternative.c

+1 −11
Original line number Diff line number Diff line
@@ -1259,22 +1259,12 @@ union text_poke_insn { 
void *text_gen_insn(u8 opcode, const void *addr, const void *dest)

{

	static union text_poke_insn insn; /* text_mutex */

	int size = 0;

	int size = text_opcode_size(opcode);



	lockdep_assert_held(&text_mutex);



	insn.opcode = opcode;



#define __CASE(insn)	\

	case insn##_INSN_OPCODE: size = insn##_INSN_SIZE; break



	switch(opcode) {

	__CASE(INT3);

	__CASE(CALL);

	__CASE(JMP32);

	__CASE(JMP8);

	}



	if (size > 1) {

		insn.disp = (long)dest - (long)(addr + size);

		if (size == 2)

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