Merge branch 'x86/alternatives' into x86/core

arch/x86/kernel/alternative.c

@@ -231,25 +231,25 @@ static void alternatives_smp_lock(u8 **start, u8 **end, u8 *text, u8 *text_end)
 			continue;
 		if (*ptr > text_end)
 			continue;
-		text_poke(*ptr, ((unsigned char []){0xf0}), 1); /* add lock prefix */
+		/* turn DS segment override prefix into lock prefix */
+		text_poke(*ptr, ((unsigned char []){0xf0}), 1);
 	};
 }
 
 static void alternatives_smp_unlock(u8 **start, u8 **end, u8 *text, u8 *text_end)
 {
 	u8 **ptr;
-	char insn[1];
 
 	if (noreplace_smp)
 		return;
 
-	add_nops(insn, 1);
 	for (ptr = start; ptr < end; ptr++) {
 		if (*ptr < text)
 			continue;
 		if (*ptr > text_end)
 			continue;
-		text_poke(*ptr, insn, 1);
+		/* turn lock prefix into DS segment override prefix */
+		text_poke(*ptr, ((unsigned char []){0x3E}), 1);
 	};
 }
 

include/asm-x86/futex.h

@@ -25,7 +25,7 @@
 	asm volatile("1:\tmovl	%2, %0\n"			\
 		     "\tmovl\t%0, %3\n"				\
 		     "\t" insn "\n"				\
-		     "2:\tlock; cmpxchgl %3, %2\n"		\
+		     "2:\t" LOCK_PREFIX "cmpxchgl %3, %2\n"	\
 		     "\tjnz\t1b\n"				\
 		     "3:\t.section .fixup,\"ax\"\n"		\
 		     "4:\tmov\t%5, %1\n"			\
@@ -64,7 +64,7 @@ static inline int futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
 		__futex_atomic_op1("xchgl %0, %2", ret, oldval, uaddr, oparg);
 		break;
 	case FUTEX_OP_ADD:
-		__futex_atomic_op1("lock; xaddl %0, %2", ret, oldval,
+		__futex_atomic_op1(LOCK_PREFIX "xaddl %0, %2", ret, oldval,
 				   uaddr, oparg);
 		break;
 	case FUTEX_OP_OR:
@@ -122,7 +122,7 @@ static inline int futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval,
 	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
 		return -EFAULT;
 
-	asm volatile("1:\tlock; cmpxchgl %3, %1\n"
+	asm volatile("1:\t" LOCK_PREFIX "cmpxchgl %3, %1\n"
 		     "2:\t.section .fixup, \"ax\"\n"
 		     "3:\tmov     %2, %0\n"
 		     "\tjmp     2b\n"

include/asm-x86/spinlock.h

@@ -97,7 +97,7 @@ static __always_inline int __ticket_spin_trylock(raw_spinlock_t *lock)
 		     "jne 1f\n\t"
 		     "movw %w0,%w1\n\t"
 		     "incb %h1\n\t"
-		     "lock ; cmpxchgw %w1,%2\n\t"
+		     LOCK_PREFIX "cmpxchgw %w1,%2\n\t"
 		     "1:"
 		     "sete %b1\n\t"
 		     "movzbl %b1,%0\n\t"
@@ -135,7 +135,7 @@ static __always_inline void __ticket_spin_lock(raw_spinlock_t *lock)
 	int inc = 0x00010000;
 	int tmp;
 
-	asm volatile("lock ; xaddl %0, %1\n"
+	asm volatile(LOCK_PREFIX "xaddl %0, %1\n"
 		     "movzwl %w0, %2\n\t"
 		     "shrl $16, %0\n\t"
 		     "1:\t"
@@ -162,7 +162,7 @@ static __always_inline int __ticket_spin_trylock(raw_spinlock_t *lock)
 		     "cmpl %0,%1\n\t"
 		     "jne 1f\n\t"
 		     "addl $0x00010000, %1\n\t"
-		     "lock ; cmpxchgl %1,%2\n\t"
+		     LOCK_PREFIX "cmpxchgl %1,%2\n\t"
 		     "1:"
 		     "sete %b1\n\t"
 		     "movzbl %b1,%0\n\t"