x86: consolidate spinlock.h

The cli and sti instructions need to be replaced by paravirt hooks.
For the i386 architecture, this is already done. The code requirements
aren't much different from x86_64 POV, so this part is consolidated in
the common header

Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

3 files changed, 64 insertions, 58 deletions

diff --git a/include/asm-x86/spinlock.h b/include/asm-x86/spinlock.h
index d74d85e71dcb..e1d555a3dfe5 100644
--- a/include/asm-x86/spinlock.h
+++ b/include/asm-x86/spinlock.h
@@ -1,5 +1,19 @@
+#ifndef _X86_SPINLOCK_H_
+#define _X86_SPINLOCK_H_
+
+#ifdef CONFIG_PARAVIRT
+#include <asm/paravirt.h>
+#else
+#define CLI_STRING      "cli"
+#define STI_STRING      "sti"
+#define CLI_STI_CLOBBERS
+#define CLI_STI_INPUT_ARGS
+#endif /* CONFIG_PARAVIRT */
+
 #ifdef CONFIG_X86_32
 # include "spinlock_32.h"
 #else
 # include "spinlock_64.h"
 #endif
+
+#endif
diff --git a/include/asm-x86/spinlock_32.h b/include/asm-x86/spinlock_32.h
index d3bcebed60ca..c42c3f12d7ce 100644
--- a/include/asm-x86/spinlock_32.h
+++ b/include/asm-x86/spinlock_32.h
@@ -5,16 +5,6 @@
 #include <asm/rwlock.h>
 #include <asm/page.h>
 #include <asm/processor.h>
-#include <linux/compiler.h>
-
-#ifdef CONFIG_PARAVIRT
-#include <asm/paravirt.h>
-#else
-#define CLI_STRING      "cli"
-#define STI_STRING      "sti"
-#define CLI_STI_CLOBBERS
-#define CLI_STI_INPUT_ARGS
-#endif /* CONFIG_PARAVIRT */
 
 /*
  * Your basic SMP spinlocks, allowing only a single CPU anywhere
@@ -27,23 +17,24 @@
  * (the type definitions are in asm/spinlock_types.h)
  */
 
-static inline int __raw_spin_is_locked(raw_spinlock_t *x)
+static inline int __raw_spin_is_locked(raw_spinlock_t *lock)
 {
-        return *(volatile signed char *)(&(x)->slock) <= 0;
+        return *(volatile signed char *)(&(lock)->slock) <= 0;
 }
 
 static inline void __raw_spin_lock(raw_spinlock_t *lock)
 {
-        asm volatile("\n1:\t"
-                     LOCK_PREFIX " ; decb %0\n\t"
-                     "jns 3f\n"
-                     "2:\t"
-                     "rep;nop\n\t"
-                     "cmpb $0,%0\n\t"
-                     "jle 2b\n\t"
-                     "jmp 1b\n"
-                     "3:\n\t"
-                     : "+m" (lock->slock) : : "memory");
+        asm volatile(
+                "\n1:\t"
+                LOCK_PREFIX " ; decb %0\n\t"
+                "jns 3f\n"
+                "2:\t"
+                "rep;nop\n\t"
+                "cmpb $0,%0\n\t"
+                "jle 2b\n\t"
+                "jmp 1b\n"
+                "3:\n\t"
+                : "+m" (lock->slock) : : "memory");
 }
 
 /*
@@ -55,7 +46,8 @@ static inline void __raw_spin_lock(raw_spinlock_t *lock)
  * irq-traced, but on CONFIG_TRACE_IRQFLAGS we never use this variant.
  */
 #ifndef CONFIG_PROVE_LOCKING
-static inline void __raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long flags)
+static inline void __raw_spin_lock_flags(raw_spinlock_t *lock,
+                                         unsigned long flags)
 {
         asm volatile(
                 "\n1:\t"
@@ -79,18 +71,20 @@ static inline void __raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long fla
                 "5:\n\t"
                 : [slock] "+m" (lock->slock)
                 : [flags] "r" (flags)
-                  CLI_STI_INPUT_ARGS
+                  CLI_STI_INPUT_ARGS
                 : "memory" CLI_STI_CLOBBERS);
 }
 #endif
 
 static inline int __raw_spin_trylock(raw_spinlock_t *lock)
 {
-        char oldval;
+        signed char oldval;
+
         asm volatile(
                 "xchgb %b0,%1"
                 :"=q" (oldval), "+m" (lock->slock)
                 :"0" (0) : "memory");
+
         return oldval > 0;
 }
 
@@ -112,7 +106,7 @@ static inline void __raw_spin_unlock(raw_spinlock_t *lock)
 
 static inline void __raw_spin_unlock(raw_spinlock_t *lock)
 {
-        char oldval = 1;
+        unsigned char oldval = 1;
 
         asm volatile("xchgb %b0, %1"
                      : "=q" (oldval), "+m" (lock->slock)
@@ -139,31 +133,16 @@ static inline void __raw_spin_unlock_wait(raw_spinlock_t *lock)
  *
  * On x86, we implement read-write locks as a 32-bit counter
  * with the high bit (sign) being the "contended" bit.
- *
- * The inline assembly is non-obvious. Think about it.
- *
- * Changed to use the same technique as rw semaphores.  See
- * semaphore.h for details.  -ben
- *
- * the helpers are in arch/i386/kernel/semaphore.c
  */
 
-/**
- * read_can_lock - would read_trylock() succeed?
- * @lock: the rwlock in question.
- */
-static inline int __raw_read_can_lock(raw_rwlock_t *x)
+static inline int __raw_read_can_lock(raw_rwlock_t *lock)
 {
-        return (int)(x)->lock > 0;
+        return (int)(lock)->lock > 0;
 }
 
-/**
- * write_can_lock - would write_trylock() succeed?
- * @lock: the rwlock in question.
- */
-static inline int __raw_write_can_lock(raw_rwlock_t *x)
+static inline int __raw_write_can_lock(raw_rwlock_t *lock)
 {
-        return (x)->lock == RW_LOCK_BIAS;
+        return (lock)->lock == RW_LOCK_BIAS;
 }
 
 static inline void __raw_read_lock(raw_rwlock_t *rw)
@@ -187,6 +166,7 @@ static inline void __raw_write_lock(raw_rwlock_t *rw)
 static inline int __raw_read_trylock(raw_rwlock_t *lock)
 {
         atomic_t *count = (atomic_t *)lock;
+
         atomic_dec(count);
         if (atomic_read(count) >= 0)
                 return 1;
@@ -197,6 +177,7 @@ static inline int __raw_read_trylock(raw_rwlock_t *lock)
 static inline int __raw_write_trylock(raw_rwlock_t *lock)
 {
         atomic_t *count = (atomic_t *)lock;
+
         if (atomic_sub_and_test(RW_LOCK_BIAS, count))
                 return 1;
         atomic_add(RW_LOCK_BIAS, count);
diff --git a/include/asm-x86/spinlock_64.h b/include/asm-x86/spinlock_64.h
index 88bf981e73cf..3b5adf92ad08 100644
--- a/include/asm-x86/spinlock_64.h
+++ b/include/asm-x86/spinlock_64.h
@@ -33,14 +33,21 @@ static inline void __raw_spin_lock(raw_spinlock_t *lock)
                 "cmpl $0,%0\n\t"
                 "jle 3b\n\t"
                 "jmp 1b\n"
-                "2:\t" : "=m" (lock->slock) : : "memory");
+                "2:\t"
+                : "=m" (lock->slock) : : "memory");
 }
 
 /*
- * Same as __raw_spin_lock, but reenable interrupts during spinning.
+ * It is easier for the lock validator if interrupts are not re-enabled
+ * in the middle of a lock-acquire. This is a performance feature anyway
+ * so we turn it off:
+ *
+ * NOTE: there's an irqs-on section here, which normally would have to be
+ * irq-traced, but on CONFIG_TRACE_IRQFLAGS we never use this variant.
  */
 #ifndef CONFIG_PROVE_LOCKING
-static inline void __raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long flags)
+static inline void __raw_spin_lock_flags(raw_spinlock_t *lock,
+                                         unsigned long flags)
 {
         asm volatile(
                 "\n1:\t"
@@ -48,12 +55,12 @@ static inline void __raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long fla
                 "jns 5f\n"
                 "testl $0x200, %1\n\t"  /* interrupts were disabled? */
                 "jz 4f\n\t"
-                "sti\n"
+                STI_STRING "\n"
                 "3:\t"
                 "rep;nop\n\t"
                 "cmpl $0, %0\n\t"
                 "jle 3b\n\t"
-                "cli\n\t"
+                CLI_STRING "\n\t"
                 "jmp 1b\n"
                 "4:\t"
                 "rep;nop\n\t"
@@ -61,7 +68,9 @@ static inline void __raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long fla
                 "jg 1b\n\t"
                 "jmp 4b\n"
                 "5:\n\t"
-                : "+m" (lock->slock) : "r" ((unsigned)flags) : "memory");
+                : "+m" (lock->slock)
+                : "r" ((unsigned)flags) CLI_STI_INPUT_ARGS
+                : "memory" CLI_STI_CLOBBERS);
 }
 #endif
 
@@ -79,7 +88,7 @@ static inline int __raw_spin_trylock(raw_spinlock_t *lock)
 
 static inline void __raw_spin_unlock(raw_spinlock_t *lock)
 {
-        asm volatile("movl $1,%0" :"=m" (lock->slock) :: "memory");
+        asm volatile("movl $1,%0" : "=m" (lock->slock) :: "memory");
 }
 
 static inline void __raw_spin_unlock_wait(raw_spinlock_t *lock)
@@ -114,18 +123,18 @@ static inline int __raw_write_can_lock(raw_rwlock_t *lock)
 
 static inline void __raw_read_lock(raw_rwlock_t *rw)
 {
-        asm volatile(LOCK_PREFIX "subl $1,(%0)\n\t"
+        asm volatile(LOCK_PREFIX " subl $1,(%0)\n\t"
                      "jns 1f\n"
-                     "call __read_lock_failed\n"
+                     "call __read_lock_failed\n\t"
                      "1:\n"
                      ::"D" (rw), "i" (RW_LOCK_BIAS) : "memory");
 }
 
 static inline void __raw_write_lock(raw_rwlock_t *rw)
 {
-        asm volatile(LOCK_PREFIX "subl %1,(%0)\n\t"
+        asm volatile(LOCK_PREFIX " subl %1,(%0)\n\t"
                      "jz 1f\n"
-                     "\tcall __write_lock_failed\n\t"
+                     "call __write_lock_failed\n\t"
                      "1:\n"
                      ::"D" (rw), "i" (RW_LOCK_BIAS) : "memory");
 }
@@ -133,6 +142,7 @@ static inline void __raw_write_lock(raw_rwlock_t *rw)
 static inline int __raw_read_trylock(raw_rwlock_t *lock)
 {
         atomic_t *count = (atomic_t *)lock;
+
         atomic_dec(count);
         if (atomic_read(count) >= 0)
                 return 1;
@@ -143,6 +153,7 @@ static inline int __raw_read_trylock(raw_rwlock_t *lock)
 static inline int __raw_write_trylock(raw_rwlock_t *lock)
 {
         atomic_t *count = (atomic_t *)lock;
+
         if (atomic_sub_and_test(RW_LOCK_BIAS, count))
                 return 1;
         atomic_add(RW_LOCK_BIAS, count);
@@ -151,12 +162,12 @@ static inline int __raw_write_trylock(raw_rwlock_t *lock)
 
 static inline void __raw_read_unlock(raw_rwlock_t *rw)
 {
-        asm volatile(LOCK_PREFIX " ; incl %0" :"=m" (rw->lock) : : "memory");
+        asm volatile(LOCK_PREFIX "incl %0" :"=m" (rw->lock) : : "memory");
 }
 
 static inline void __raw_write_unlock(raw_rwlock_t *rw)
 {
-        asm volatile(LOCK_PREFIX " ; addl $" RW_LOCK_BIAS_STR ",%0"
+        asm volatile(LOCK_PREFIX "addl $" RW_LOCK_BIAS_STR ",%0"
                                 : "=m" (rw->lock) : : "memory");
 }