[PATCH 4/8] x86: Tell irq work about self IPI support

From: Frederic Weisbecker
Date: Sat Sep 20 2014 - 16:31:47 EST


x86 supports irq work self-IPIs when local apic is available. This is
partly known on runtime so lets implement arch_irq_work_has_interrupt()
accordingly.

This should be safely called after setup_arch().

Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
---
arch/x86/include/asm/Kbuild | 1 -
arch/x86/include/asm/irq_work.h | 11 +++++++++++
arch/x86/kernel/irq_work.c | 2 +-
3 files changed, 12 insertions(+), 2 deletions(-)
create mode 100644 arch/x86/include/asm/irq_work.h

diff --git a/arch/x86/include/asm/Kbuild b/arch/x86/include/asm/Kbuild
index 8fa909c..3bf000f 100644
--- a/arch/x86/include/asm/Kbuild
+++ b/arch/x86/include/asm/Kbuild
@@ -7,6 +7,5 @@ genhdr-y += unistd_x32.h
generic-y += clkdev.h
generic-y += cputime.h
generic-y += early_ioremap.h
-generic-y += irq_work.h
generic-y += mcs_spinlock.h
generic-y += scatterlist.h
diff --git a/arch/x86/include/asm/irq_work.h b/arch/x86/include/asm/irq_work.h
new file mode 100644
index 0000000..78162f8
--- /dev/null
+++ b/arch/x86/include/asm/irq_work.h
@@ -0,0 +1,11 @@
+#ifndef _ASM_IRQ_WORK_H
+#define _ASM_IRQ_WORK_H
+
+#include <asm/processor.h>
+
+static inline bool arch_irq_work_has_interrupt(void)
+{
+ return cpu_has_apic;
+}
+
+#endif /* _ASM_IRQ_WORK_H */
diff --git a/arch/x86/kernel/irq_work.c b/arch/x86/kernel/irq_work.c
index 1de84e3..15d741d 100644
--- a/arch/x86/kernel/irq_work.c
+++ b/arch/x86/kernel/irq_work.c
@@ -41,7 +41,7 @@ __visible void smp_trace_irq_work_interrupt(struct pt_regs *regs)
void arch_irq_work_raise(void)
{
#ifdef CONFIG_X86_LOCAL_APIC
- if (!cpu_has_apic)
+ if (!arch_irq_work_has_interrupt())
return;

apic->send_IPI_self(IRQ_WORK_VECTOR);
--
2.1.0

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