From 76b235c6bcb16062d663e2ee96db0b69f2e6bc14 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 24 Jul 2015 14:45:44 +0200 Subject: [PATCH] jump_label: Rename JUMP_LABEL_{EN,DIS}ABLE to JUMP_LABEL_{JMP,NOP} Since we've already stepped away from ENABLE is a JMP and DISABLE is a NOP with the branch_default bits, and are going to make it even worse, rename it to make it all clearer. This way we don't mix multiple levels of logic attributes, but have a plain 'physical' name for what the current instruction patching status of a jump label is. This is a first step in removing the naming confusion that has led to a stream of avoidable bugs such as: a833581e372a ("x86, perf: Fix static_key bug in load_mm_cr4()") Signed-off-by: Peter Zijlstra (Intel) Cc: Andrew Morton Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org [ Beefed up the changelog. ] Signed-off-by: Ingo Molnar --- arch/arm/kernel/jump_label.c | 2 +- arch/arm64/kernel/jump_label.c | 2 +- arch/mips/kernel/jump_label.c | 2 +- arch/powerpc/kernel/jump_label.c | 2 +- arch/s390/kernel/jump_label.c | 2 +- arch/sparc/kernel/jump_label.c | 2 +- arch/x86/kernel/jump_label.c | 2 +- include/linux/jump_label.h | 4 ++-- kernel/jump_label.c | 18 +++++++++--------- 9 files changed, 18 insertions(+), 18 deletions(-) diff --git a/arch/arm/kernel/jump_label.c b/arch/arm/kernel/jump_label.c index e39cbf4..845a5dd9 100644 --- a/arch/arm/kernel/jump_label.c +++ b/arch/arm/kernel/jump_label.c @@ -12,7 +12,7 @@ static void __arch_jump_label_transform(struct jump_entry *entry, void *addr = (void *)entry->code; unsigned int insn; - if (type == JUMP_LABEL_ENABLE) + if (type == JUMP_LABEL_JMP) insn = arm_gen_branch(entry->code, entry->target); else insn = arm_gen_nop(); diff --git a/arch/arm64/kernel/jump_label.c b/arch/arm64/kernel/jump_label.c index 4f1fec7..c2dd1ad 100644 --- a/arch/arm64/kernel/jump_label.c +++ b/arch/arm64/kernel/jump_label.c @@ -28,7 +28,7 @@ void arch_jump_label_transform(struct jump_entry *entry, void *addr = (void *)entry->code; u32 insn; - if (type == JUMP_LABEL_ENABLE) { + if (type == JUMP_LABEL_JMP) { insn = aarch64_insn_gen_branch_imm(entry->code, entry->target, AARCH64_INSN_BRANCH_NOLINK); diff --git a/arch/mips/kernel/jump_label.c b/arch/mips/kernel/jump_label.c index dda800e..3e586da 100644 --- a/arch/mips/kernel/jump_label.c +++ b/arch/mips/kernel/jump_label.c @@ -51,7 +51,7 @@ void arch_jump_label_transform(struct jump_entry *e, /* Target must have the right alignment and ISA must be preserved. */ BUG_ON((e->target & J_ALIGN_MASK) != J_ISA_BIT); - if (type == JUMP_LABEL_ENABLE) { + if (type == JUMP_LABEL_JMP) { insn.j_format.opcode = J_ISA_BIT ? mm_j32_op : j_op; insn.j_format.target = e->target >> J_RANGE_SHIFT; } else { diff --git a/arch/powerpc/kernel/jump_label.c b/arch/powerpc/kernel/jump_label.c index a1ed8a8c..6472472 100644 --- a/arch/powerpc/kernel/jump_label.c +++ b/arch/powerpc/kernel/jump_label.c @@ -17,7 +17,7 @@ void arch_jump_label_transform(struct jump_entry *entry, { u32 *addr = (u32 *)(unsigned long)entry->code; - if (type == JUMP_LABEL_ENABLE) + if (type == JUMP_LABEL_JMP) patch_branch(addr, entry->target, 0); else patch_instruction(addr, PPC_INST_NOP); diff --git a/arch/s390/kernel/jump_label.c b/arch/s390/kernel/jump_label.c index a902996..a83d224 100644 --- a/arch/s390/kernel/jump_label.c +++ b/arch/s390/kernel/jump_label.c @@ -64,7 +64,7 @@ static void __jump_label_transform(struct jump_entry *entry, { struct insn old, new; - if (type == JUMP_LABEL_ENABLE) { + if (type == JUMP_LABEL_JMP) { jump_label_make_nop(entry, &old); jump_label_make_branch(entry, &new); } else { diff --git a/arch/sparc/kernel/jump_label.c b/arch/sparc/kernel/jump_label.c index 48565c1..59bbeff 100644 --- a/arch/sparc/kernel/jump_label.c +++ b/arch/sparc/kernel/jump_label.c @@ -16,7 +16,7 @@ void arch_jump_label_transform(struct jump_entry *entry, u32 val; u32 *insn = (u32 *) (unsigned long) entry->code; - if (type == JUMP_LABEL_ENABLE) { + if (type == JUMP_LABEL_JMP) { s32 off = (s32)entry->target - (s32)entry->code; #ifdef CONFIG_SPARC64 diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c index 26d5a55..e565e0e 100644 --- a/arch/x86/kernel/jump_label.c +++ b/arch/x86/kernel/jump_label.c @@ -45,7 +45,7 @@ static void __jump_label_transform(struct jump_entry *entry, const unsigned char default_nop[] = { STATIC_KEY_INIT_NOP }; const unsigned char *ideal_nop = ideal_nops[NOP_ATOMIC5]; - if (type == JUMP_LABEL_ENABLE) { + if (type == JUMP_LABEL_JMP) { if (init) { /* * Jump label is enabled for the first time. diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h index f4de473..6a8b4fe 100644 --- a/include/linux/jump_label.h +++ b/include/linux/jump_label.h @@ -86,8 +86,8 @@ struct static_key { #ifndef __ASSEMBLY__ enum jump_label_type { - JUMP_LABEL_DISABLE = 0, - JUMP_LABEL_ENABLE, + JUMP_LABEL_NOP = 0, + JUMP_LABEL_JMP, }; struct module; diff --git a/kernel/jump_label.c b/kernel/jump_label.c index 52ebaca..96d8945 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -65,9 +65,9 @@ void static_key_slow_inc(struct static_key *key) jump_label_lock(); if (atomic_read(&key->enabled) == 0) { if (!jump_label_get_branch_default(key)) - jump_label_update(key, JUMP_LABEL_ENABLE); + jump_label_update(key, JUMP_LABEL_JMP); else - jump_label_update(key, JUMP_LABEL_DISABLE); + jump_label_update(key, JUMP_LABEL_NOP); } atomic_inc(&key->enabled); jump_label_unlock(); @@ -88,9 +88,9 @@ static void __static_key_slow_dec(struct static_key *key, schedule_delayed_work(work, rate_limit); } else { if (!jump_label_get_branch_default(key)) - jump_label_update(key, JUMP_LABEL_DISABLE); + jump_label_update(key, JUMP_LABEL_NOP); else - jump_label_update(key, JUMP_LABEL_ENABLE); + jump_label_update(key, JUMP_LABEL_JMP); } jump_label_unlock(); } @@ -184,9 +184,9 @@ static enum jump_label_type jump_label_type(struct static_key *key) bool state = static_key_enabled(key); if ((!true_branch && state) || (true_branch && !state)) - return JUMP_LABEL_ENABLE; + return JUMP_LABEL_JMP; - return JUMP_LABEL_DISABLE; + return JUMP_LABEL_NOP; } void __init jump_label_init(void) @@ -276,7 +276,7 @@ void jump_label_apply_nops(struct module *mod) return; for (iter = iter_start; iter < iter_stop; iter++) { - arch_jump_label_transform_static(iter, JUMP_LABEL_DISABLE); + arch_jump_label_transform_static(iter, JUMP_LABEL_NOP); } } @@ -318,8 +318,8 @@ static int jump_label_add_module(struct module *mod) jlm->next = key->next; key->next = jlm; - if (jump_label_type(key) == JUMP_LABEL_ENABLE) - __jump_label_update(key, iter, iter_stop, JUMP_LABEL_ENABLE); + if (jump_label_type(key) == JUMP_LABEL_JMP) + __jump_label_update(key, iter, iter_stop, JUMP_LABEL_JMP); } return 0; -- 2.7.4