[Xen-devel] [RFC PATCH 14/33] subarch support for controlling interrupt delivery

[Chris Wright <chrisw@xxxxxxxxxxxx>]

Abstract the code that controls interrupt delivery, and add a separate
subarch implementation for Xen that manipulates a shared-memory event
delivery mask.

Signed-off-by: Ian Pratt <ian.pratt@xxxxxxxxxxxxx>
Signed-off-by: Christian Limpach <Christian.Limpach@xxxxxxxxxxxx>
Signed-off-by: Chris Wright <chrisw@xxxxxxxxxxxx>

---
 arch/i386/mach-xen/Makefile                   |    2 
 arch/i386/mach-xen/interrupt.c                |   67 +++++++++++++++++++++++++
 include/asm-i386/irqflags.h                   |   61 +---------------------
 include/asm-i386/mach-default/mach_irqflags.h |   64 +++++++++++++++++++++++
 include/asm-i386/mach-default/mach_system.h   |    4 +
 include/asm-i386/mach-xen/mach_irqflags.h     |   29 ++++++++++
 include/asm-i386/mach-xen/mach_system.h       |    5 +
 7 files changed, 174 insertions(+), 58 deletions(-)


diff -r 092b7e56c85d arch/i386/mach-xen/Makefile
--- a/arch/i386/mach-xen/Makefile       Thu Jul 13 14:42:42 2006 -0700
+++ b/arch/i386/mach-xen/Makefile       Thu Jul 13 14:42:42 2006 -0700
@@ -4,6 +4,6 @@
 
 extra-y                                := head.o
 
-obj-y                          := setup.o setup-xen.o memory.o
+obj-y                          := setup.o setup-xen.o memory.o interrupt.o
 
 setup-y                                := ../mach-default/setup.o
diff -r 092b7e56c85d include/asm-i386/irqflags.h
--- a/include/asm-i386/irqflags.h       Thu Jul 13 14:42:42 2006 -0700
+++ b/include/asm-i386/irqflags.h       Thu Jul 13 14:42:42 2006 -0700
@@ -10,66 +10,12 @@
 #ifndef _ASM_IRQFLAGS_H
 #define _ASM_IRQFLAGS_H
 
+#include <mach_irqflags.h>
+
 #ifndef __ASSEMBLY__
-
-static inline unsigned long __raw_local_save_flags(void)
-{
-       unsigned long flags;
-
-       __asm__ __volatile__(
-               "pushfl ; popl %0"
-               : "=g" (flags)
-               : /* no input */
-       );
-
-       return flags;
-}
 
 #define raw_local_save_flags(flags) \
                do { (flags) = __raw_local_save_flags(); } while (0)
-
-static inline void raw_local_irq_restore(unsigned long flags)
-{
-       __asm__ __volatile__(
-               "pushl %0 ; popfl"
-               : /* no output */
-               :"g" (flags)
-               :"memory", "cc"
-       );
-}
-
-static inline void raw_local_irq_disable(void)
-{
-       __asm__ __volatile__("cli" : : : "memory");
-}
-
-static inline void raw_local_irq_enable(void)
-{
-       __asm__ __volatile__("sti" : : : "memory");
-}
-
-/*
- * Used in the idle loop; sti takes one instruction cycle
- * to complete:
- */
-static inline void raw_safe_halt(void)
-{
-       __asm__ __volatile__("sti; hlt" : : : "memory");
-}
-
-/*
- * Used when interrupts are already enabled or to
- * shutdown the processor:
- */
-static inline void halt(void)
-{
-       __asm__ __volatile__("hlt": : :"memory");
-}
-
-static inline int raw_irqs_disabled_flags(unsigned long flags)
-{
-       return !(flags & (1 << 9));
-}
 
 static inline int raw_irqs_disabled(void)
 {
@@ -93,7 +39,7 @@ static inline unsigned long __raw_local_
 #define raw_local_irq_save(flags) \
                do { (flags) = __raw_local_irq_save(); } while (0)
 
-#endif /* __ASSEMBLY__ */
+#endif /* __ASSEMBLY__ */
 
 /*
  * Do the CPU's IRQ-state tracing from assembly code. We call a
@@ -124,4 +70,5 @@ static inline unsigned long __raw_local_
 # define TRACE_IRQS_OFF
 #endif
 
+
 #endif
diff -r 092b7e56c85d arch/i386/mach-xen/interrupt.c
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/arch/i386/mach-xen/interrupt.c    Thu Jul 13 16:00:43 2006 -0700
@@ -0,0 +1,67 @@
+#include <linux/preempt.h>
+#include <linux/module.h>
+
+#include <asm/hypervisor.h>
+#include <mach_irqflags.h>
+
+
+/*
+ * The use of 'barrier' in the following reflects their use as local-lock
+ * operations. Reentrancy must be prevented (e.g., __cli()) /before/ following
+ * critical operations are executed. All critical operations must complete
+ * /before/ reentrancy is permitted (e.g., __sti()).
+ */
+unsigned long __raw_local_save_flags(void)
+{
+       struct vcpu_info *_vcpu;
+       unsigned long flags;
+
+       preempt_disable();
+       _vcpu = &HYPERVISOR_shared_info->vcpu_info[__vcpu_id];
+       flags = _vcpu->evtchn_upcall_mask;
+       preempt_enable();
+
+       return flags;
+}
+EXPORT_SYMBOL(__raw_local_save_flags);
+
+void raw_local_irq_restore(unsigned long flags)
+{
+       struct vcpu_info *_vcpu;
+
+       preempt_disable();
+
+       _vcpu = &HYPERVISOR_shared_info->vcpu_info[__vcpu_id];
+       if ((_vcpu->evtchn_upcall_mask = flags) == 0) {
+               barrier(); /* unmask then check (avoid races) */
+               if (unlikely(_vcpu->evtchn_upcall_pending))
+                       force_evtchn_callback();
+               preempt_enable();
+       } else
+               preempt_enable_no_resched();
+}
+EXPORT_SYMBOL(raw_local_irq_restore);
+
+void raw_local_irq_disable(void)
+{
+       struct vcpu_info *_vcpu;
+       preempt_disable();
+       _vcpu = &HYPERVISOR_shared_info->vcpu_info[__vcpu_id];
+       _vcpu->evtchn_upcall_mask = 1;
+       preempt_enable_no_resched();
+}
+EXPORT_SYMBOL(raw_local_irq_disable);
+
+void raw_local_irq_enable(void)
+{
+       struct vcpu_info *_vcpu;
+
+       preempt_disable();
+       _vcpu = &HYPERVISOR_shared_info->vcpu_info[__vcpu_id];
+       _vcpu->evtchn_upcall_mask = 0;
+       barrier(); /* unmask then check (avoid races) */
+       if (unlikely(_vcpu->evtchn_upcall_pending))
+               force_evtchn_callback();
+       preempt_enable();
+}
+EXPORT_SYMBOL(raw_local_irq_enable);
diff -r 092b7e56c85d include/asm-i386/mach-default/mach_irqflags.h
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/include/asm-i386/mach-default/mach_irqflags.h     Thu Jul 13 14:42:42 
2006 -0700
@@ -0,0 +1,64 @@
+#ifndef ASM_MACH_IRQFLAGS_H
+#define ASM_MACH_IRQFLAGS_H
+
+#ifndef __ASSEMBLY__
+
+static inline unsigned long __raw_local_save_flags(void)
+{
+       unsigned long flags;
+
+       __asm__ __volatile__(
+               "pushfl ; popl %0"
+               : "=g" (flags)
+               : /* no input */
+       );
+
+       return flags;
+}
+
+static inline void raw_local_irq_restore(unsigned long flags)
+{
+       __asm__ __volatile__(
+               "pushl %0 ; popfl"
+               : /* no output */
+               :"g" (flags)
+               :"memory", "cc"
+       );
+}
+
+static inline void raw_local_irq_disable(void)
+{
+       __asm__ __volatile__("cli" : : : "memory");
+}
+
+static inline void raw_local_irq_enable(void)
+{
+       __asm__ __volatile__("sti" : : : "memory");
+}
+
+/*
+ * Used in the idle loop; sti takes one instruction cycle
+ * to complete:
+ */
+static inline void raw_safe_halt(void)
+{
+       __asm__ __volatile__("sti; hlt" : : : "memory");
+}
+
+/*
+ * Used when interrupts are already enabled or to
+ * shutdown the processor:
+ */
+static inline void halt(void)
+{
+       __asm__ __volatile__("hlt": : :"memory");
+}
+
+static inline int raw_irqs_disabled_flags(unsigned long flags)
+{
+       return !(flags & (1 << 9));
+}
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* ASM_MACH_IRQFLAGS_H */
diff -r 092b7e56c85d include/asm-i386/mach-default/mach_system.h
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/include/asm-i386/mach-default/mach_system.h       Thu Jul 13 15:59:13 
2006 -0700
@@ -0,0 +1,4 @@
+#ifndef __ASM_MACH_SYSTEM_H
+#define __ASM_MACH_SYSTEM_H
+
+#endif /* __ASM_MACH_SYSTEM_H */
diff -r 092b7e56c85d include/asm-i386/mach-xen/mach_irqflags.h
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/include/asm-i386/mach-xen/mach_irqflags.h Thu Jul 13 14:42:42 2006 -0700
@@ -0,0 +1,29 @@
+#ifndef ASM_MACH_IRQFLAGS_H
+#define ASM_MACH_IRQFLAGS_H
+
+#ifndef __ASSEMBLY__
+
+#ifdef CONFIG_SMP
+#define __vcpu_id smp_processor_id()
+#else
+#define __vcpu_id 0
+#endif
+
+/* interrupt control.. */
+
+unsigned long __raw_local_save_flags(void);
+void raw_local_irq_restore(unsigned long flags);
+void raw_local_irq_disable(void);
+void raw_local_irq_enable(void);
+
+#define raw_safe_halt()                do { } while(0)
+#define halt()                 do { } while(0)
+
+static inline int raw_irqs_disabled_flags(unsigned long flags)
+{
+       return flags != 0;
+}
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* ASM_MACH_IRQFLAGS_H */
diff -r 092b7e56c85d include/asm-i386/mach-xen/mach_system.h
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/include/asm-i386/mach-xen/mach_system.h   Thu Jul 13 15:59:13 2006 -0700
@@ -0,0 +1,5 @@
+#ifndef __ASM_MACH_SYSTEM_H
+#define __ASM_MACH_SYSTEM_H
+
+
+#endif /* __ASM_MACH_SYSTEM_H */

--

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