Commit d5de8841 authored by Jeremy Fitzhardinge's avatar Jeremy Fitzhardinge Committed by Ingo Molnar
Browse files

x86: split spinlock implementations out into their own files 



ftrace requires certain low-level code, like spinlocks and timestamps,
to be compiled without -pg in order to avoid infinite recursion.  This
patch splits out the core paravirt spinlocks and the Xen spinlocks
into separate files which can be compiled without -pg.

Also do xen/time.c while we're about it.  As a result, we can now use
ftrace within a Xen domain.

Signed-off-by: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 338b9bb3

arch/x86/kernel/Makefile

+2 −2
Original line number Diff line number Diff line
@@ -10,7 +10,7 @@ ifdef CONFIG_FTRACE 
# Do not profile debug and lowlevel utilities

CFLAGS_REMOVE_tsc.o = -pg

CFLAGS_REMOVE_rtc.o = -pg

CFLAGS_REMOVE_paravirt.o = -pg

CFLAGS_REMOVE_paravirt-spinlocks.o = -pg

endif



#
@@ -89,7 +89,7 @@ obj-$(CONFIG_DEBUG_NX_TEST) += test_nx.o 
obj-$(CONFIG_VMI)		+= vmi_32.o vmiclock_32.o

obj-$(CONFIG_KVM_GUEST)		+= kvm.o

obj-$(CONFIG_KVM_CLOCK)		+= kvmclock.o

obj-$(CONFIG_PARAVIRT)		+= paravirt.o paravirt_patch_$(BITS).o

obj-$(CONFIG_PARAVIRT)		+= paravirt.o paravirt_patch_$(BITS).o paravirt-spinlocks.o

obj-$(CONFIG_PARAVIRT_CLOCK)	+= pvclock.o



obj-$(CONFIG_PCSPKR_PLATFORM)	+= pcspeaker.o

arch/x86/kernel/paravirt-spinlocks.c

0 → 100644
+31 −0
Original line number Diff line number Diff line 
/*

 * Split spinlock implementation out into its own file, so it can be

 * compiled in a FTRACE-compatible way.

 */

#include <linux/spinlock.h>

#include <linux/module.h>



#include <asm/paravirt.h>



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);



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

}

arch/x86/kernel/paravirt.c

+0 −23
Original line number Diff line number Diff line
@@ -268,17 +268,6 @@ 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,
@@ -461,18 +450,6 @@ 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);

arch/x86/xen/Makefile

+7 −1
Original line number Diff line number Diff line 
ifdef CONFIG_FTRACE

# Do not profile debug and lowlevel utilities

CFLAGS_REMOVE_spinlock.o = -pg

CFLAGS_REMOVE_time.o = -pg

endif



obj-y		:= enlighten.o setup.o multicalls.o mmu.o \

			time.o xen-asm_$(BITS).o grant-table.o suspend.o



obj-$(CONFIG_SMP)	+= smp.o
 
obj-$(CONFIG_SMP)	+= smp.o spinlock.o

arch/x86/xen/smp.c

+0 −167
Original line number Diff line number Diff line
@@ -15,7 +15,6 @@ 
 * This does not handle HOTPLUG_CPU yet.

 */

#include <linux/sched.h>

#include <linux/kernel_stat.h>

#include <linux/err.h>

#include <linux/smp.h>
@@ -36,8 +35,6 @@ 
#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);
@@ -419,170 +416,6 @@ 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,

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