Merge branch 'x86/paravirt-spinlocks' into x86/for-linus

4 files changed, 148 insertions, 16 deletions

diff --git a/include/asm-x86/paravirt.h b/include/asm-x86/paravirt.h
index 695ce9383f52..aec9767836b6 100644
--- a/include/asm-x86/paravirt.h
+++ b/include/asm-x86/paravirt.h
@@ -325,6 +325,15 @@ struct pv_mmu_ops {
                            unsigned long phys, pgprot_t flags);
 };
 
+struct raw_spinlock;
+struct pv_lock_ops {
+        int (*spin_is_locked)(struct raw_spinlock *lock);
+        int (*spin_is_contended)(struct raw_spinlock *lock);
+        void (*spin_lock)(struct raw_spinlock *lock);
+        int (*spin_trylock)(struct raw_spinlock *lock);
+        void (*spin_unlock)(struct raw_spinlock *lock);
+};
+
 /* This contains all the paravirt structures: we get a convenient
  * number for each function using the offset which we use to indicate
  * what to patch. */
@@ -335,6 +344,7 @@ struct paravirt_patch_template {
         struct pv_irq_ops pv_irq_ops;
         struct pv_apic_ops pv_apic_ops;
         struct pv_mmu_ops pv_mmu_ops;
+        struct pv_lock_ops pv_lock_ops;
 };
 
 extern struct pv_info pv_info;
@@ -344,6 +354,7 @@ extern struct pv_cpu_ops pv_cpu_ops;
 extern struct pv_irq_ops pv_irq_ops;
 extern struct pv_apic_ops pv_apic_ops;
 extern struct pv_mmu_ops pv_mmu_ops;
+extern struct pv_lock_ops pv_lock_ops;
 
 #define PARAVIRT_PATCH(x)                                       \
         (offsetof(struct paravirt_patch_template, x) / sizeof(void *))
@@ -1368,6 +1379,37 @@ static inline void __set_fixmap(unsigned /* enum fixed_addresses */ idx,
 void _paravirt_nop(void);
 #define paravirt_nop    ((void *)_paravirt_nop)
 
+void paravirt_use_bytelocks(void);
+
+#ifdef CONFIG_SMP
+
+static inline int __raw_spin_is_locked(struct raw_spinlock *lock)
+{
+        return PVOP_CALL1(int, pv_lock_ops.spin_is_locked, lock);
+}
+
+static inline int __raw_spin_is_contended(struct raw_spinlock *lock)
+{
+        return PVOP_CALL1(int, pv_lock_ops.spin_is_contended, lock);
+}
+
+static __always_inline void __raw_spin_lock(struct raw_spinlock *lock)
+{
+        PVOP_VCALL1(pv_lock_ops.spin_lock, lock);
+}
+
+static __always_inline int __raw_spin_trylock(struct raw_spinlock *lock)
+{
+        return PVOP_CALL1(int, pv_lock_ops.spin_trylock, lock);
+}
+
+static __always_inline void __raw_spin_unlock(struct raw_spinlock *lock)
+{
+        PVOP_VCALL1(pv_lock_ops.spin_unlock, lock);
+}
+
+#endif
+
 /* These all sit in the .parainstructions section to tell us what to patch. */
 struct paravirt_patch_site {
         u8 *instr;              /* original instructions */
@@ -1452,6 +1494,7 @@ static inline unsigned long __raw_local_irq_save(void)
         return f;
 }
 
+
 /* Make sure as little as possible of this mess escapes. */
 #undef PARAVIRT_CALL
 #undef __PVOP_CALL
diff --git a/include/asm-x86/spinlock.h b/include/asm-x86/spinlock.h
index 21e89bf92f1c..4f9a9861799a 100644
--- a/include/asm-x86/spinlock.h
+++ b/include/asm-x86/spinlock.h
@@ -6,7 +6,7 @@
 #include <asm/page.h>
 #include <asm/processor.h>
 #include <linux/compiler.h>
-
+#include <asm/paravirt.h>
 /*
  * Your basic SMP spinlocks, allowing only a single CPU anywhere
  *
@@ -54,21 +54,21 @@
  * much between them in performance though, especially as locks are out of line.
  */
 #if (NR_CPUS < 256)
-static inline int __raw_spin_is_locked(raw_spinlock_t *lock)
+static inline int __ticket_spin_is_locked(raw_spinlock_t *lock)
 {
         int tmp = ACCESS_ONCE(lock->slock);
 
         return (((tmp >> 8) & 0xff) != (tmp & 0xff));
 }
 
-static inline int __raw_spin_is_contended(raw_spinlock_t *lock)
+static inline int __ticket_spin_is_contended(raw_spinlock_t *lock)
 {
         int tmp = ACCESS_ONCE(lock->slock);
 
         return (((tmp >> 8) & 0xff) - (tmp & 0xff)) > 1;
 }
 
-static __always_inline void __raw_spin_lock(raw_spinlock_t *lock)
+static __always_inline void __ticket_spin_lock(raw_spinlock_t *lock)
 {
         short inc = 0x0100;
 
@@ -87,9 +87,7 @@ static __always_inline void __raw_spin_lock(raw_spinlock_t *lock)
                 : "memory", "cc");
 }
 
-#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock)
-
-static __always_inline int __raw_spin_trylock(raw_spinlock_t *lock)
+static __always_inline int __ticket_spin_trylock(raw_spinlock_t *lock)
 {
         int tmp;
         short new;
@@ -110,7 +108,7 @@ static __always_inline int __raw_spin_trylock(raw_spinlock_t *lock)
         return tmp;
 }
 
-static __always_inline void __raw_spin_unlock(raw_spinlock_t *lock)
+static __always_inline void __ticket_spin_unlock(raw_spinlock_t *lock)
 {
         asm volatile(UNLOCK_LOCK_PREFIX "incb %0"
                      : "+m" (lock->slock)
@@ -118,21 +116,21 @@ static __always_inline void __raw_spin_unlock(raw_spinlock_t *lock)
                      : "memory", "cc");
 }
 #else
-static inline int __raw_spin_is_locked(raw_spinlock_t *lock)
+static inline int __ticket_spin_is_locked(raw_spinlock_t *lock)
 {
         int tmp = ACCESS_ONCE(lock->slock);
 
         return (((tmp >> 16) & 0xffff) != (tmp & 0xffff));
 }
 
-static inline int __raw_spin_is_contended(raw_spinlock_t *lock)
+static inline int __ticket_spin_is_contended(raw_spinlock_t *lock)
 {
         int tmp = ACCESS_ONCE(lock->slock);
 
         return (((tmp >> 16) & 0xffff) - (tmp & 0xffff)) > 1;
 }
 
-static __always_inline void __raw_spin_lock(raw_spinlock_t *lock)
+static __always_inline void __ticket_spin_lock(raw_spinlock_t *lock)
 {
         int inc = 0x00010000;
         int tmp;
@@ -153,9 +151,7 @@ static __always_inline void __raw_spin_lock(raw_spinlock_t *lock)
                      : "memory", "cc");
 }
 
-#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock)
-
-static __always_inline int __raw_spin_trylock(raw_spinlock_t *lock)
+static __always_inline int __ticket_spin_trylock(raw_spinlock_t *lock)
 {
         int tmp;
         int new;
@@ -177,7 +173,7 @@ static __always_inline int __raw_spin_trylock(raw_spinlock_t *lock)
         return tmp;
 }
 
-static __always_inline void __raw_spin_unlock(raw_spinlock_t *lock)
+static __always_inline void __ticket_spin_unlock(raw_spinlock_t *lock)
 {
         asm volatile(UNLOCK_LOCK_PREFIX "incw %0"
                      : "+m" (lock->slock)
@@ -186,6 +182,98 @@ static __always_inline void __raw_spin_unlock(raw_spinlock_t *lock)
 }
 #endif
 
+#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock)
+
+#ifdef CONFIG_PARAVIRT
+/*
+ * Define virtualization-friendly old-style lock byte lock, for use in
+ * pv_lock_ops if desired.
+ *
+ * This differs from the pre-2.6.24 spinlock by always using xchgb
+ * rather than decb to take the lock; this allows it to use a
+ * zero-initialized lock structure.  It also maintains a 1-byte
+ * contention counter, so that we can implement
+ * __byte_spin_is_contended.
+ */
+struct __byte_spinlock {
+        s8 lock;
+        s8 spinners;
+};
+
+static inline int __byte_spin_is_locked(raw_spinlock_t *lock)
+{
+        struct __byte_spinlock *bl = (struct __byte_spinlock *)lock;
+        return bl->lock != 0;
+}
+
+static inline int __byte_spin_is_contended(raw_spinlock_t *lock)
+{
+        struct __byte_spinlock *bl = (struct __byte_spinlock *)lock;
+        return bl->spinners != 0;
+}
+
+static inline void __byte_spin_lock(raw_spinlock_t *lock)
+{
+        struct __byte_spinlock *bl = (struct __byte_spinlock *)lock;
+        s8 val = 1;
+
+        asm("1: xchgb %1, %0\n"
+            "   test %1,%1\n"
+            "   jz 3f\n"
+            "   " LOCK_PREFIX "incb %2\n"
+            "2: rep;nop\n"
+            "   cmpb $1, %0\n"
+            "   je 2b\n"
+            "   " LOCK_PREFIX "decb %2\n"
+            "   jmp 1b\n"
+            "3:"
+            : "+m" (bl->lock), "+q" (val), "+m" (bl->spinners): : "memory");
+}
+
+static inline int __byte_spin_trylock(raw_spinlock_t *lock)
+{
+        struct __byte_spinlock *bl = (struct __byte_spinlock *)lock;
+        u8 old = 1;
+
+        asm("xchgb %1,%0"
+            : "+m" (bl->lock), "+q" (old) : : "memory");
+
+        return old == 0;
+}
+
+static inline void __byte_spin_unlock(raw_spinlock_t *lock)
+{
+        struct __byte_spinlock *bl = (struct __byte_spinlock *)lock;
+        smp_wmb();
+        bl->lock = 0;
+}
+#else  /* !CONFIG_PARAVIRT */
+static inline int __raw_spin_is_locked(raw_spinlock_t *lock)
+{
+        return __ticket_spin_is_locked(lock);
+}
+
+static inline int __raw_spin_is_contended(raw_spinlock_t *lock)
+{
+        return __ticket_spin_is_contended(lock);
+}
+
+static __always_inline void __raw_spin_lock(raw_spinlock_t *lock)
+{
+        __ticket_spin_lock(lock);
+}
+
+static __always_inline int __raw_spin_trylock(raw_spinlock_t *lock)
+{
+        return __ticket_spin_trylock(lock);
+}
+
+static __always_inline void __raw_spin_unlock(raw_spinlock_t *lock)
+{
+        __ticket_spin_unlock(lock);
+}
+#endif  /* CONFIG_PARAVIRT */
+
 static inline void __raw_spin_unlock_wait(raw_spinlock_t *lock)
 {
         while (__raw_spin_is_locked(lock))
diff --git a/include/asm-x86/spinlock_types.h b/include/asm-x86/spinlock_types.h
index 9029cf78cf5d..06c071c9eee9 100644
--- a/include/asm-x86/spinlock_types.h
+++ b/include/asm-x86/spinlock_types.h
@@ -5,7 +5,7 @@
 # error "please don't include this file directly"
 #endif
 
-typedef struct {
+typedef struct raw_spinlock {
         unsigned int slock;
 } raw_spinlock_t;
 
diff --git a/include/asm-x86/xen/events.h b/include/asm-x86/xen/events.h
index f8d57ea1f05f..8ded74720024 100644
--- a/include/asm-x86/xen/events.h
+++ b/include/asm-x86/xen/events.h
@@ -5,6 +5,7 @@ enum ipi_vector {
         XEN_RESCHEDULE_VECTOR,
         XEN_CALL_FUNCTION_VECTOR,
         XEN_CALL_FUNCTION_SINGLE_VECTOR,
+        XEN_SPIN_UNLOCK_VECTOR,
 
         XEN_NR_IPIS,
 };