This patch creates two new functions, __jump_label_enabling_check() and __jump_label_disabling_check(), to make the respective check before updating a jump_entry.
Signed-off-by: Daniel Bristot de Oliveira <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: Pavel Tatashin <[email protected]> Cc: Masami Hiramatsu <[email protected]> Cc: "Steven Rostedt (VMware)" <[email protected]> Cc: Zhou Chengming <[email protected]> Cc: Jiri Kosina <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: "Peter Zijlstra (Intel)" <[email protected]> Cc: Chris von Recklinghausen <[email protected]> Cc: Jason Baron <[email protected]> Cc: Scott Wood <[email protected]> Cc: Marcelo Tosatti <[email protected]> Cc: Clark Williams <[email protected]> Cc: [email protected] Cc: [email protected] --- arch/x86/kernel/jump_label.c | 88 ++++++++++++++++++++++-------------- 1 file changed, 53 insertions(+), 35 deletions(-) diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c index eeea935e9bb5..a11d836d9aaa 100644 --- a/arch/x86/kernel/jump_label.c +++ b/arch/x86/kernel/jump_label.c @@ -37,57 +37,75 @@ static void bug_at(unsigned char *ip, int line) BUG(); } +static inline void __jump_label_enabling_check(struct jump_entry *entry, + enum jump_label_type type, + int init) +{ + const unsigned char default_nop[] = { STATIC_KEY_INIT_NOP }; + const unsigned char *ideal_nop = ideal_nops[NOP_ATOMIC5]; + + if (init) { + /* + * Jump label is enabled for the first time. + * So we expect a default_nop... + */ + if (unlikely(memcmp((void *)entry->code, default_nop, 5) + != 0)) + bug_at((void *)entry->code, __LINE__); + } else { + /* + * ...otherwise expect an ideal_nop. Otherwise + * something went horribly wrong. + */ + if (unlikely(memcmp((void *)entry->code, ideal_nop, 5) + != 0)) + bug_at((void *)entry->code, __LINE__); + } +} + +static inline void __jump_label_disabling_check(struct jump_entry *entry, + enum jump_label_type type, + int init) +{ + union jump_code_union code; + const unsigned char default_nop[] = { STATIC_KEY_INIT_NOP }; + + /* + * We are disabling this jump label. If it is not what + * we think it is, then something must have gone wrong. + * If this is the first initialization call, then we + * are converting the default nop to the ideal nop. + */ + if (init) { + if (unlikely(memcmp((void *)entry->code, default_nop, 5) != 0)) + bug_at((void *)entry->code, __LINE__); + } else { + code.jump = 0xe9; + code.offset = entry->target - + (entry->code + JUMP_LABEL_NOP_SIZE); + if (unlikely(memcmp((void *)entry->code, &code, 5) != 0)) + bug_at((void *)entry->code, __LINE__); + } +} + static void __ref __jump_label_transform(struct jump_entry *entry, enum jump_label_type type, void *(*poker)(void *, const void *, size_t), int init) { union jump_code_union code; - const unsigned char default_nop[] = { STATIC_KEY_INIT_NOP }; - const unsigned char *ideal_nop = ideal_nops[NOP_ATOMIC5]; if (early_boot_irqs_disabled) poker = text_poke_early; if (type == JUMP_LABEL_JMP) { - if (init) { - /* - * Jump label is enabled for the first time. - * So we expect a default_nop... - */ - if (unlikely(memcmp((void *)entry->code, default_nop, 5) - != 0)) - bug_at((void *)entry->code, __LINE__); - } else { - /* - * ...otherwise expect an ideal_nop. Otherwise - * something went horribly wrong. - */ - if (unlikely(memcmp((void *)entry->code, ideal_nop, 5) - != 0)) - bug_at((void *)entry->code, __LINE__); - } + __jump_label_enabling_check(entry, type, init); code.jump = 0xe9; code.offset = entry->target - (entry->code + JUMP_LABEL_NOP_SIZE); } else { - /* - * We are disabling this jump label. If it is not what - * we think it is, then something must have gone wrong. - * If this is the first initialization call, then we - * are converting the default nop to the ideal nop. - */ - if (init) { - if (unlikely(memcmp((void *)entry->code, default_nop, 5) != 0)) - bug_at((void *)entry->code, __LINE__); - } else { - code.jump = 0xe9; - code.offset = entry->target - - (entry->code + JUMP_LABEL_NOP_SIZE); - if (unlikely(memcmp((void *)entry->code, &code, 5) != 0)) - bug_at((void *)entry->code, __LINE__); - } + __jump_label_disabling_check(entry, type, init); memcpy(&code, ideal_nops[NOP_ATOMIC5], JUMP_LABEL_NOP_SIZE); } -- 2.17.1
