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:

  a833581e ("x86, perf: Fix static_key bug in load_mm_cr4()")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
[ Beefed up the changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

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();

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);

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 {

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);

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 {

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

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.

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;

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;