From 63f62addb88ec4b358cf4574789bc3180c689e9a Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 3 Oct 2019 14:50:42 +0200 Subject: x86/alternatives: Add and use text_gen_insn() helper Provide a simple helper function to create common instruction encodings. Tested-by: Alexei Starovoitov Tested-by: Steven Rostedt (VMware) Signed-off-by: Peter Zijlstra (Intel) Acked-by: Alexei Starovoitov Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Daniel Bristot de Oliveira Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Masami Hiramatsu Cc: Steven Rostedt Cc: Thomas Gleixner Link: https://lkml.kernel.org/r/20191111132457.703538332@infradead.org Signed-off-by: Ingo Molnar --- arch/x86/kernel/jump_label.c | 31 +++++++++++-------------------- 1 file changed, 11 insertions(+), 20 deletions(-) (limited to 'arch/x86/kernel/jump_label.c') diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c index cf8c847c7b5d..9c4498ea0b3c 100644 --- a/arch/x86/kernel/jump_label.c +++ b/arch/x86/kernel/jump_label.c @@ -16,15 +16,7 @@ #include #include -union jump_code_union { - char code[JUMP_LABEL_NOP_SIZE]; - struct { - char jump; - int offset; - } __attribute__((packed)); -}; - -static void bug_at(unsigned char *ip, int line) +static void bug_at(const void *ip, int line) { /* * The location is not an op that we were expecting. @@ -38,33 +30,32 @@ static void bug_at(unsigned char *ip, int line) static const void * __jump_label_set_jump_code(struct jump_entry *entry, enum jump_label_type type, int init) { - static union jump_code_union code; /* relies on text_mutex */ const unsigned char default_nop[] = { STATIC_KEY_INIT_NOP }; const unsigned char *ideal_nop = ideal_nops[NOP_ATOMIC5]; - const void *expect; + const void *expect, *code; + const void *addr, *dest; int line; - lockdep_assert_held(&text_mutex); + addr = (void *)jump_entry_code(entry); + dest = (void *)jump_entry_target(entry); - code.jump = JMP32_INSN_OPCODE; - code.offset = jump_entry_target(entry) - - (jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE); + code = text_gen_insn(JMP32_INSN_OPCODE, addr, dest); if (init) { expect = default_nop; line = __LINE__; } else if (type == JUMP_LABEL_JMP) { expect = ideal_nop; line = __LINE__; } else { - expect = code.code; line = __LINE__; + expect = code; line = __LINE__; } - if (memcmp((void *)jump_entry_code(entry), expect, JUMP_LABEL_NOP_SIZE)) - bug_at((void *)jump_entry_code(entry), line); + if (memcmp(addr, expect, JUMP_LABEL_NOP_SIZE)) + bug_at(addr, line); if (type == JUMP_LABEL_NOP) - memcpy(&code, ideal_nop, JUMP_LABEL_NOP_SIZE); + code = ideal_nop; - return &code; + return code; } static void inline __jump_label_transform(struct jump_entry *entry, -- cgit v1.2.3