# HG changeset patch
# User kaf24@xxxxxxxxxxxxxxxxxxxx
# Node ID 6cf6f878328241adf7e07aa58b01b9d5a53574c0
# Parent 475e2a8493b803916b63a68712a4e49abebe1026
Fix local_irq_save() and irqs_disabled() to be preemption-safe.
Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx>
diff -r 475e2a8493b8 -r 6cf6f8783282
linux-2.6-xen-sparse/include/asm-xen/asm-i386/system.h
--- a/linux-2.6-xen-sparse/include/asm-xen/asm-i386/system.h Sat Oct 15
16:19:43 2005
+++ b/linux-2.6-xen-sparse/include/asm-xen/asm-i386/system.h Sun Oct 16
10:45:51 2005
@@ -497,22 +497,11 @@
* includes these barriers, for example.
*/
-/*
- * Don't use smp_processor_id() in preemptible code: debug builds will barf.
- * It's okay in these cases as we only read the upcall mask in preemptible
- * regions, which is always safe.
- */
-#ifdef CONFIG_SMP
-#define __this_cpu() __smp_processor_id()
-#else
-#define __this_cpu() 0
-#endif
-
#define __cli()
\
do { \
vcpu_info_t *_vcpu; \
preempt_disable(); \
- _vcpu = &HYPERVISOR_shared_info->vcpu_data[__this_cpu()]; \
+ _vcpu = &HYPERVISOR_shared_info->vcpu_data[smp_processor_id()]; \
_vcpu->evtchn_upcall_mask = 1; \
preempt_enable_no_resched(); \
barrier(); \
@@ -523,7 +512,7 @@
vcpu_info_t *_vcpu; \
barrier(); \
preempt_disable(); \
- _vcpu = &HYPERVISOR_shared_info->vcpu_data[__this_cpu()]; \
+ _vcpu = &HYPERVISOR_shared_info->vcpu_data[smp_processor_id()]; \
_vcpu->evtchn_upcall_mask = 0; \
barrier(); /* unmask then check (avoid races) */ \
if ( unlikely(_vcpu->evtchn_upcall_pending) ) \
@@ -534,8 +523,10 @@
#define __save_flags(x)
\
do { \
vcpu_info_t *_vcpu; \
- _vcpu = &HYPERVISOR_shared_info->vcpu_data[__this_cpu()]; \
+ preempt_disable(); \
+ _vcpu = &HYPERVISOR_shared_info->vcpu_data[smp_processor_id()]; \
(x) = _vcpu->evtchn_upcall_mask; \
+ preempt_enable(); \
} while (0)
#define __restore_flags(x) \
@@ -543,7 +534,7 @@
vcpu_info_t *_vcpu; \
barrier(); \
preempt_disable(); \
- _vcpu = &HYPERVISOR_shared_info->vcpu_data[__this_cpu()]; \
+ _vcpu = &HYPERVISOR_shared_info->vcpu_data[smp_processor_id()]; \
if ((_vcpu->evtchn_upcall_mask = (x)) == 0) { \
barrier(); /* unmask then check (avoid races) */ \
if ( unlikely(_vcpu->evtchn_upcall_pending) ) \
@@ -559,7 +550,7 @@
do { \
vcpu_info_t *_vcpu; \
preempt_disable(); \
- _vcpu = &HYPERVISOR_shared_info->vcpu_data[__this_cpu()]; \
+ _vcpu = &HYPERVISOR_shared_info->vcpu_data[smp_processor_id()]; \
(x) = _vcpu->evtchn_upcall_mask; \
_vcpu->evtchn_upcall_mask = 1; \
preempt_enable_no_resched(); \
@@ -572,8 +563,15 @@
#define local_irq_disable() __cli()
#define local_irq_enable() __sti()
+/* Cannot use preempt_enable() here as we would recurse in preempt_sched(). */
#define irqs_disabled()
\
- HYPERVISOR_shared_info->vcpu_data[__this_cpu()].evtchn_upcall_mask
+({ int ___x; \
+ vcpu_info_t *_vcpu; \
+ preempt_disable(); \
+ _vcpu = &HYPERVISOR_shared_info->vcpu_data[smp_processor_id()]; \
+ ___x = (_vcpu->evtchn_upcall_mask != 0); \
+ preempt_enable_no_resched(); \
+ ___x; })
/*
* disable hlt during certain critical i/o operations
diff -r 475e2a8493b8 -r 6cf6f8783282
linux-2.6-xen-sparse/include/asm-xen/asm-x86_64/system.h
--- a/linux-2.6-xen-sparse/include/asm-xen/asm-x86_64/system.h Sat Oct 15
16:19:43 2005
+++ b/linux-2.6-xen-sparse/include/asm-xen/asm-x86_64/system.h Sun Oct 16
10:45:51 2005
@@ -321,22 +321,11 @@
* includes these barriers, for example.
*/
-/*
- * Don't use smp_processor_id() in preemptible code: debug builds will barf.
- * It's okay in these cases as we only read the upcall mask in preemptible
- * regions, which is always safe.
- */
-#ifdef CONFIG_SMP
-#define __this_cpu() __smp_processor_id()
-#else
-#define __this_cpu() 0
-#endif
-
#define __cli()
\
do { \
vcpu_info_t *_vcpu; \
preempt_disable(); \
- _vcpu = &HYPERVISOR_shared_info->vcpu_data[__this_cpu()]; \
+ _vcpu = &HYPERVISOR_shared_info->vcpu_data[smp_processor_id()]; \
_vcpu->evtchn_upcall_mask = 1; \
preempt_enable_no_resched(); \
barrier(); \
@@ -347,7 +336,7 @@
vcpu_info_t *_vcpu; \
barrier(); \
preempt_disable(); \
- _vcpu = &HYPERVISOR_shared_info->vcpu_data[__this_cpu()]; \
+ _vcpu = &HYPERVISOR_shared_info->vcpu_data[smp_processor_id()]; \
_vcpu->evtchn_upcall_mask = 0; \
barrier(); /* unmask then check (avoid races) */ \
if ( unlikely(_vcpu->evtchn_upcall_pending) ) \
@@ -358,8 +347,10 @@
#define __save_flags(x)
\
do { \
vcpu_info_t *_vcpu; \
- _vcpu = &HYPERVISOR_shared_info->vcpu_data[__this_cpu()]; \
+ preempt_disable(); \
+ _vcpu = &HYPERVISOR_shared_info->vcpu_data[smp_processor_id()]; \
(x) = _vcpu->evtchn_upcall_mask; \
+ preempt_enable(); \
} while (0)
#define __restore_flags(x) \
@@ -367,7 +358,7 @@
vcpu_info_t *_vcpu; \
barrier(); \
preempt_disable(); \
- _vcpu = &HYPERVISOR_shared_info->vcpu_data[__this_cpu()]; \
+ _vcpu = &HYPERVISOR_shared_info->vcpu_data[smp_processor_id()]; \
if ((_vcpu->evtchn_upcall_mask = (x)) == 0) { \
barrier(); /* unmask then check (avoid races) */ \
if ( unlikely(_vcpu->evtchn_upcall_pending) ) \
@@ -383,7 +374,7 @@
do { \
vcpu_info_t *_vcpu; \
preempt_disable(); \
- _vcpu = &HYPERVISOR_shared_info->vcpu_data[__this_cpu()]; \
+ _vcpu = &HYPERVISOR_shared_info->vcpu_data[smp_processor_id()]; \
(x) = _vcpu->evtchn_upcall_mask; \
_vcpu->evtchn_upcall_mask = 1; \
preempt_enable_no_resched(); \
@@ -398,8 +389,15 @@
#define local_irq_disable() __cli()
#define local_irq_enable() __sti()
+/* Cannot use preempt_enable() here as we would recurse in preempt_sched(). */
#define irqs_disabled()
\
- HYPERVISOR_shared_info->vcpu_data[__this_cpu()].evtchn_upcall_mask
+({ int ___x; \
+ vcpu_info_t *_vcpu; \
+ preempt_disable(); \
+ _vcpu = &HYPERVISOR_shared_info->vcpu_data[smp_processor_id()]; \
+ ___x = (_vcpu->evtchn_upcall_mask != 0); \
+ preempt_enable_no_resched(); \
+ ___x; })
/*
* disable hlt during certain critical i/o operations
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