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Diffstat (limited to 'arch')
-rw-r--r--arch/arm/include/asm/smp.h9
-rw-r--r--arch/arm/kernel/smp.c6
-rw-r--r--arch/arm/kernel/traps.c11
3 files changed, 25 insertions, 1 deletions
diff --git a/arch/arm/include/asm/smp.h b/arch/arm/include/asm/smp.h
index 3d6dc8b460e4..daf869cff02e 100644
--- a/arch/arm/include/asm/smp.h
+++ b/arch/arm/include/asm/smp.h
@@ -18,6 +18,15 @@
# error "<asm/smp.h> included in non-SMP build"
#endif
+/*
+ * Identify which IPIs are safe for the irqchip to handle using FIQ.
+ *
+ * This information is advisory. The interrupt controller may not be capable
+ * of routing these IPIs to FIQ and the kernel will continue to work if they
+ * are routed to IRQ as normal.
+ */
+#define SMP_IPI_FIQ_MASK 0x80
+
#define raw_smp_processor_id() (current_thread_info()->cpu)
struct seq_file;
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index baee70267f29..631c5e53e286 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -644,6 +644,11 @@ void handle_IPI(int ipinr, struct pt_regs *regs)
break;
case IPI_CPU_BACKTRACE:
+ if (in_nmi()) {
+ nmi_cpu_backtrace(regs);
+ break;
+ }
+
irq_enter();
nmi_cpu_backtrace(regs);
irq_exit();
@@ -755,6 +760,7 @@ static void raise_nmi(cpumask_t *mask)
if (cpumask_test_cpu(smp_processor_id(), mask) && irqs_disabled())
nmi_cpu_backtrace(NULL);
+ BUILD_BUG_ON(SMP_IPI_FIQ_MASK != BIT(IPI_CPU_BACKTRACE));
smp_cross_call(mask, IPI_CPU_BACKTRACE);
}
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index bc698383e822..8f6173cd0a54 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -479,7 +479,16 @@ asmlinkage void __exception_irq_entry handle_fiq_as_nmi(struct pt_regs *regs)
nmi_enter();
- /* nop. FIQ handlers for special arch/arm features can be added here. */
+ /*
+ * Either the interrupt controller supports FIQ, meaning it will
+ * do the right thing with this call, or we will end up treating a
+ * spurious FIQ (which is normally fatal) as though it were an IRQ
+ * which, although it risks deadlock, still gives us a sporting
+ * chance of surviving long enough to log errors.
+ */
+#ifdef CONFIG_MULTI_IRQ_HANDLER
+ handle_arch_irq(regs);
+#endif
nmi_exit();