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x86/ftrace: Use text_gen_insn()

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Replace the ftrace_code_union with the generic text_gen_insn() helper,
which does exactly this.

Tested-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Alexei 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/20191111132457.932808000@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra
2019-10-09 12:44:14 +02:00
committed by Ingo Molnar
parent 254d2c0451
commit 67c1d4a280
3 changed files with 36 additions and 52 deletions
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30
arch/x86/include/asm/text-patching.h
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@@ -80,7 +80,35 @@ static inline int text_opcode_size(u8 opcode)
return size;
}
extern void *text_gen_insn(u8 opcode, const void *addr, const void *dest);
union text_poke_insn {
u8 text[POKE_MAX_OPCODE_SIZE];
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;