1 files changed, 96 insertions, 25 deletions

diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c
index e631c358f7f4..044053235302 100644
--- a/arch/x86/kernel/jump_label.c
+++ b/arch/x86/kernel/jump_label.c
@@ -35,41 +35,43 @@ static void bug_at(unsigned char *ip, int line)
 	BUG();
 }
 
-static void __ref __jump_label_transform(struct jump_entry *entry,
-					 enum jump_label_type type,
-					 int init)
+static void __jump_label_set_jump_code(struct jump_entry *entry,
+				       enum jump_label_type type,
+				       union jump_code_union *code,
+				       int init)
 {
-	union jump_code_union jmp;
 	const unsigned char default_nop[] = { STATIC_KEY_INIT_NOP };
 	const unsigned char *ideal_nop = ideal_nops[NOP_ATOMIC5];
-	const void *expect, *code;
+	const void *expect;
 	int line;
 
-	jmp.jump = 0xe9;
-	jmp.offset = jump_entry_target(entry) -
-		     (jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE);
+	code->jump = 0xe9;
+	code->offset = jump_entry_target(entry) -
+		       (jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE);
 
-	if (type == JUMP_LABEL_JMP) {
-		if (init) {
-			expect = default_nop; line = __LINE__;
-		} else {
-			expect = ideal_nop; line = __LINE__;
-		}
-
-		code = &jmp.code;
+	if (init) {
+		expect = default_nop; line = __LINE__;
+	} else if (type == JUMP_LABEL_JMP) {
+		expect = ideal_nop; line = __LINE__;
 	} else {
-		if (init) {
-			expect = default_nop; line = __LINE__;
-		} else {
-			expect = &jmp.code; line = __LINE__;
-		}
-
-		code = ideal_nop;
+		expect = code->code; line = __LINE__;
 	}
 
 	if (memcmp((void *)jump_entry_code(entry), expect, JUMP_LABEL_NOP_SIZE))
 		bug_at((void *)jump_entry_code(entry), line);
 
+	if (type == JUMP_LABEL_NOP)
+		memcpy(code, ideal_nop, JUMP_LABEL_NOP_SIZE);
+}
+
+static void __ref __jump_label_transform(struct jump_entry *entry,
+					 enum jump_label_type type,
+					 int init)
+{
+	union jump_code_union code;
+
+	__jump_label_set_jump_code(entry, type, &code, init);
+
 	/*
 	 * As long as only a single processor is running and the code is still
 	 * not marked as RO, text_poke_early() can be used; Checking that
@@ -82,12 +84,12 @@ static void __ref __jump_label_transform(struct jump_entry *entry,
 	 * always nop being the 'currently valid' instruction
 	 */
 	if (init || system_state == SYSTEM_BOOTING) {
-		text_poke_early((void *)jump_entry_code(entry), code,
+		text_poke_early((void *)jump_entry_code(entry), &code,
 				JUMP_LABEL_NOP_SIZE);
 		return;
 	}
 
-	text_poke_bp((void *)jump_entry_code(entry), code, JUMP_LABEL_NOP_SIZE,
+	text_poke_bp((void *)jump_entry_code(entry), &code, JUMP_LABEL_NOP_SIZE,
 		     (void *)jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE);
 }
 
@@ -99,6 +101,75 @@ void arch_jump_label_transform(struct jump_entry *entry,
 	mutex_unlock(&text_mutex);
 }
 
+#define TP_VEC_MAX (PAGE_SIZE / sizeof(struct text_poke_loc))
+static struct text_poke_loc tp_vec[TP_VEC_MAX];
+static int tp_vec_nr;
+
+bool arch_jump_label_transform_queue(struct jump_entry *entry,
+				     enum jump_label_type type)
+{
+	struct text_poke_loc *tp;
+	void *entry_code;
+
+	if (system_state == SYSTEM_BOOTING) {
+		/*
+		 * Fallback to the non-batching mode.
+		 */
+		arch_jump_label_transform(entry, type);
+		return true;
+	}
+
+	/*
+	 * No more space in the vector, tell upper layer to apply
+	 * the queue before continuing.
+	 */
+	if (tp_vec_nr == TP_VEC_MAX)
+		return false;
+
+	tp = &tp_vec[tp_vec_nr];
+
+	entry_code = (void *)jump_entry_code(entry);
+
+	/*
+	 * The INT3 handler will do a bsearch in the queue, so we need entries
+	 * to be sorted. We can survive an unsorted list by rejecting the entry,
+	 * forcing the generic jump_label code to apply the queue. Warning once,
+	 * to raise the attention to the case of an unsorted entry that is
+	 * better not happen, because, in the worst case we will perform in the
+	 * same way as we do without batching - with some more overhead.
+	 */
+	if (tp_vec_nr > 0) {
+		int prev = tp_vec_nr - 1;
+		struct text_poke_loc *prev_tp = &tp_vec[prev];
+
+		if (WARN_ON_ONCE(prev_tp->addr > entry_code))
+			return false;
+	}
+
+	__jump_label_set_jump_code(entry, type,
+				   (union jump_code_union *) &tp->opcode, 0);
+
+	tp->addr = entry_code;
+	tp->detour = entry_code + JUMP_LABEL_NOP_SIZE;
+	tp->len = JUMP_LABEL_NOP_SIZE;
+
+	tp_vec_nr++;
+
+	return true;
+}
+
+void arch_jump_label_transform_apply(void)
+{
+	if (!tp_vec_nr)
+		return;
+
+	mutex_lock(&text_mutex);
+	text_poke_bp_batch(tp_vec, tp_vec_nr);
+	mutex_unlock(&text_mutex);
+
+	tp_vec_nr = 0;
+}
+
 static enum {
 	JL_STATE_START,
 	JL_STATE_NO_UPDATE,