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-rw-r--r--arch/x86/kernel/Makefile3
-rw-r--r--arch/x86/kernel/paravirt.c24
-rw-r--r--arch/x86/xen/smp.c171
-rw-r--r--drivers/xen/events.c27
-rw-r--r--include/asm-x86/paravirt.h43
-rw-r--r--include/asm-x86/spinlock.h118
-rw-r--r--include/asm-x86/spinlock_types.h2
-rw-r--r--include/asm-x86/xen/events.h1
-rw-r--r--include/xen/events.h7
9 files changed, 379 insertions, 17 deletions
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index b78a17b1281..3db651fc8ec 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -7,9 +7,10 @@ extra-y := head_$(BITS).o head$(BITS).o head.o init_task.o vmlinu
CPPFLAGS_vmlinux.lds += -U$(UTS_MACHINE)
ifdef CONFIG_FTRACE
-# Do not profile debug utilities
+# Do not profile debug and lowlevel utilities
CFLAGS_REMOVE_tsc.o = -pg
CFLAGS_REMOVE_rtc.o = -pg
+CFLAGS_REMOVE_paravirt.o = -pg
endif
#
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index b4564d089b4..097d8a6797f 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -124,6 +124,7 @@ static void *get_call_destination(u8 type)
.pv_irq_ops = pv_irq_ops,
.pv_apic_ops = pv_apic_ops,
.pv_mmu_ops = pv_mmu_ops,
+ .pv_lock_ops = pv_lock_ops,
};
return *((void **)&tmpl + type);
}
@@ -267,6 +268,17 @@ enum paravirt_lazy_mode paravirt_get_lazy_mode(void)
return __get_cpu_var(paravirt_lazy_mode);
}
+void __init paravirt_use_bytelocks(void)
+{
+#ifdef CONFIG_SMP
+ pv_lock_ops.spin_is_locked = __byte_spin_is_locked;
+ pv_lock_ops.spin_is_contended = __byte_spin_is_contended;
+ pv_lock_ops.spin_lock = __byte_spin_lock;
+ pv_lock_ops.spin_trylock = __byte_spin_trylock;
+ pv_lock_ops.spin_unlock = __byte_spin_unlock;
+#endif
+}
+
struct pv_info pv_info = {
.name = "bare hardware",
.paravirt_enabled = 0,
@@ -449,6 +461,18 @@ struct pv_mmu_ops pv_mmu_ops = {
.set_fixmap = native_set_fixmap,
};
+struct pv_lock_ops pv_lock_ops = {
+#ifdef CONFIG_SMP
+ .spin_is_locked = __ticket_spin_is_locked,
+ .spin_is_contended = __ticket_spin_is_contended,
+
+ .spin_lock = __ticket_spin_lock,
+ .spin_trylock = __ticket_spin_trylock,
+ .spin_unlock = __ticket_spin_unlock,
+#endif
+};
+EXPORT_SYMBOL_GPL(pv_lock_ops);
+
EXPORT_SYMBOL_GPL(pv_time_ops);
EXPORT_SYMBOL (pv_cpu_ops);
EXPORT_SYMBOL (pv_mmu_ops);
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index f702199312a..e693812ac59 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -15,6 +15,7 @@
* This does not handle HOTPLUG_CPU yet.
*/
#include <linux/sched.h>
+#include <linux/kernel_stat.h>
#include <linux/err.h>
#include <linux/smp.h>
@@ -35,6 +36,8 @@
#include "xen-ops.h"
#include "mmu.h"
+static void __cpuinit xen_init_lock_cpu(int cpu);
+
cpumask_t xen_cpu_initialized_map;
static DEFINE_PER_CPU(int, resched_irq);
@@ -179,6 +182,8 @@ static void __init xen_smp_prepare_cpus(unsigned int max_cpus)
{
unsigned cpu;
+ xen_init_lock_cpu(0);
+
smp_store_cpu_info(0);
cpu_data(0).x86_max_cores = 1;
set_cpu_sibling_map(0);
@@ -301,6 +306,7 @@ static int __cpuinit xen_cpu_up(unsigned int cpu)
clear_tsk_thread_flag(idle, TIF_FORK);
#endif
xen_setup_timer(cpu);
+ xen_init_lock_cpu(cpu);
per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
@@ -413,6 +419,170 @@ static irqreturn_t xen_call_function_single_interrupt(int irq, void *dev_id)
return IRQ_HANDLED;
}
+struct xen_spinlock {
+ unsigned char lock; /* 0 -> free; 1 -> locked */
+ unsigned short spinners; /* count of waiting cpus */
+};
+
+static int xen_spin_is_locked(struct raw_spinlock *lock)
+{
+ struct xen_spinlock *xl = (struct xen_spinlock *)lock;
+
+ return xl->lock != 0;
+}
+
+static int xen_spin_is_contended(struct raw_spinlock *lock)
+{
+ struct xen_spinlock *xl = (struct xen_spinlock *)lock;
+
+ /* Not strictly true; this is only the count of contended
+ lock-takers entering the slow path. */
+ return xl->spinners != 0;
+}
+
+static int xen_spin_trylock(struct raw_spinlock *lock)
+{
+ struct xen_spinlock *xl = (struct xen_spinlock *)lock;
+ u8 old = 1;
+
+ asm("xchgb %b0,%1"
+ : "+q" (old), "+m" (xl->lock) : : "memory");
+
+ return old == 0;
+}
+
+static DEFINE_PER_CPU(int, lock_kicker_irq) = -1;
+static DEFINE_PER_CPU(struct xen_spinlock *, lock_spinners);
+
+static inline void spinning_lock(struct xen_spinlock *xl)
+{
+ __get_cpu_var(lock_spinners) = xl;
+ wmb(); /* set lock of interest before count */
+ asm(LOCK_PREFIX " incw %0"
+ : "+m" (xl->spinners) : : "memory");
+}
+
+static inline void unspinning_lock(struct xen_spinlock *xl)
+{
+ asm(LOCK_PREFIX " decw %0"
+ : "+m" (xl->spinners) : : "memory");
+ wmb(); /* decrement count before clearing lock */
+ __get_cpu_var(lock_spinners) = NULL;
+}
+
+static noinline int xen_spin_lock_slow(struct raw_spinlock *lock)
+{
+ struct xen_spinlock *xl = (struct xen_spinlock *)lock;
+ int irq = __get_cpu_var(lock_kicker_irq);
+ int ret;
+
+ /* If kicker interrupts not initialized yet, just spin */
+ if (irq == -1)
+ return 0;
+
+ /* announce we're spinning */
+ spinning_lock(xl);
+
+ /* clear pending */
+ xen_clear_irq_pending(irq);
+
+ /* check again make sure it didn't become free while
+ we weren't looking */
+ ret = xen_spin_trylock(lock);
+ if (ret)
+ goto out;
+
+ /* block until irq becomes pending */
+ xen_poll_irq(irq);
+ kstat_this_cpu.irqs[irq]++;
+
+out:
+ unspinning_lock(xl);
+ return ret;
+}
+
+static void xen_spin_lock(struct raw_spinlock *lock)
+{
+ struct xen_spinlock *xl = (struct xen_spinlock *)lock;
+ int timeout;
+ u8 oldval;
+
+ do {
+ timeout = 1 << 10;
+
+ asm("1: xchgb %1,%0\n"
+ " testb %1,%1\n"
+ " jz 3f\n"
+ "2: rep;nop\n"
+ " cmpb $0,%0\n"
+ " je 1b\n"
+ " dec %2\n"
+ " jnz 2b\n"
+ "3:\n"
+ : "+m" (xl->lock), "=q" (oldval), "+r" (timeout)
+ : "1" (1)
+ : "memory");
+
+ } while (unlikely(oldval != 0 && !xen_spin_lock_slow(lock)));
+}
+
+static noinline void xen_spin_unlock_slow(struct xen_spinlock *xl)
+{
+ int cpu;
+
+ for_each_online_cpu(cpu) {
+ /* XXX should mix up next cpu selection */
+ if (per_cpu(lock_spinners, cpu) == xl) {
+ xen_send_IPI_one(cpu, XEN_SPIN_UNLOCK_VECTOR);
+ break;
+ }
+ }
+}
+
+static void xen_spin_unlock(struct raw_spinlock *lock)
+{
+ struct xen_spinlock *xl = (struct xen_spinlock *)lock;
+
+ smp_wmb(); /* make sure no writes get moved after unlock */
+ xl->lock = 0; /* release lock */
+
+ /* make sure unlock happens before kick */
+ barrier();
+
+ if (unlikely(xl->spinners))
+ xen_spin_unlock_slow(xl);
+}
+
+static __cpuinit void xen_init_lock_cpu(int cpu)
+{
+ int irq;
+ const char *name;
+
+ name = kasprintf(GFP_KERNEL, "spinlock%d", cpu);
+ irq = bind_ipi_to_irqhandler(XEN_SPIN_UNLOCK_VECTOR,
+ cpu,
+ xen_reschedule_interrupt,
+ IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING,
+ name,
+ NULL);
+
+ if (irq >= 0) {
+ disable_irq(irq); /* make sure it's never delivered */
+ per_cpu(lock_kicker_irq, cpu) = irq;
+ }
+
+ printk("cpu %d spinlock event irq %d\n", cpu, irq);
+}
+
+static void __init xen_init_spinlocks(void)
+{
+ pv_lock_ops.spin_is_locked = xen_spin_is_locked;
+ pv_lock_ops.spin_is_contended = xen_spin_is_contended;
+ pv_lock_ops.spin_lock = xen_spin_lock;
+ pv_lock_ops.spin_trylock = xen_spin_trylock;
+ pv_lock_ops.spin_unlock = xen_spin_unlock;
+}
+
static const struct smp_ops xen_smp_ops __initdata = {
.smp_prepare_boot_cpu = xen_smp_prepare_boot_cpu,
.smp_prepare_cpus = xen_smp_prepare_cpus,
@@ -430,4 +600,5 @@ void __init xen_smp_init(void)
{
smp_ops = xen_smp_ops;
xen_fill_possible_map();
+ xen_init_spinlocks();
}
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 332dd63750a..0e0c28574af 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -734,6 +734,33 @@ static void restore_cpu_ipis(unsigned int cpu)
}
}
+/* Clear an irq's pending state, in preparation for polling on it */
+void xen_clear_irq_pending(int irq)
+{
+ int evtchn = evtchn_from_irq(irq);
+
+ if (VALID_EVTCHN(evtchn))
+ clear_evtchn(evtchn);
+}
+
+/* Poll waiting for an irq to become pending. In the usual case, the
+ irq will be disabled so it won't deliver an interrupt. */
+void xen_poll_irq(int irq)
+{
+ evtchn_port_t evtchn = evtchn_from_irq(irq);
+
+ if (VALID_EVTCHN(evtchn)) {
+ struct sched_poll poll;
+
+ poll.nr_ports = 1;
+ poll.timeout = 0;
+ poll.ports = &evtchn;
+
+ if (HYPERVISOR_sched_op(SCHEDOP_poll, &poll) != 0)
+ BUG();
+ }
+}
+
void xen_irq_resume(void)
{
unsigned int cpu, irq, evtchn;
diff --git a/include/asm-x86/paravirt.h b/include/asm-x86/paravirt.h
index 695ce9383f5..aec9767836b 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 21e89bf92f1..4f9a9861799 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 9029cf78cf5..06c071c9eee 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 f8d57ea1f05..8ded7472002 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,
};
diff --git a/include/xen/events.h b/include/xen/events.h
index 67c4436554a..4680ff3fbc9 100644
--- a/include/xen/events.h
+++ b/include/xen/events.h
@@ -44,4 +44,11 @@ extern void notify_remote_via_irq(int irq);
extern void xen_irq_resume(void);
+/* Clear an irq's pending state, in preparation for polling on it */
+void xen_clear_irq_pending(int irq);
+
+/* Poll waiting for an irq to become pending. In the usual case, the
+ irq will be disabled so it won't deliver an interrupt. */
+void xen_poll_irq(int irq);
+
#endif /* _XEN_EVENTS_H */
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-24 04:07:32 +0000