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author | Peter Zijlstra <peterz@infradead.org> | 2019-10-09 13:44:14 +0300 |
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committer | Ingo Molnar <mingo@kernel.org> | 2019-11-27 09:44:24 +0300 |
commit | 67c1d4a28064f9ec63df03f7798e4a334176a9cd (patch) | |
tree | 6194a25303109c696bfd23f85b8d3e27c263a353 /arch/x86/include/asm/text-patching.h | |
parent | 254d2c04515ea4532a503cc5d8649e1513042e56 (diff) | |
download | linux-67c1d4a28064f9ec63df03f7798e4a334176a9cd.tar.xz |
x86/ftrace: Use text_gen_insn()
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>
Diffstat (limited to 'arch/x86/include/asm/text-patching.h')
-rw-r--r-- | arch/x86/include/asm/text-patching.h | 30 |
1 files changed, 29 insertions, 1 deletions
diff --git a/arch/x86/include/asm/text-patching.h b/arch/x86/include/asm/text-patching.h index 93e4266cd5a3..ad8f9f433a1b 100644 --- a/arch/x86/include/asm/text-patching.h +++ b/arch/x86/include/asm/text-patching.h @@ -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; |