summaryrefslogtreecommitdiff
path: root/arch/arm/kernel
diff options
context:
space:
mode:
authorStephen Boyd <sboyd@codeaurora.org>2013-10-29 20:32:56 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2013-11-07 00:21:26 +0000
commitbf18525fd793101df42a1344ecc48b49b62e48c9 (patch)
treef21c8dab2f929ff4b5410ef8355bfba10c34aa45 /arch/arm/kernel
parent8d451442549a2696880288ba6325f9681451231b (diff)
ARM: 7872/1: Support arch_irq_work_raise() via self IPIs
By default, IRQ work is run from the tick interrupt (see irq_work_run() in update_process_times()). When we're in full NOHZ mode, restarting the tick requires the use of IRQ work and if the only place we run IRQ work is in the tick interrupt we have an unbreakable cycle. Implement arch_irq_work_raise() via self IPIs to break this cycle and get the tick started again. Note that we implement this via IPIs which are only available on SMP builds. This shouldn't be a problem because full NOHZ is only supported on SMP builds anyway. Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Reviewed-by: Kevin Hilman <khilman@linaro.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/kernel')
-rw-r--r--arch/arm/kernel/smp.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 72024ea8a3a6..bf9a0d6d91dc 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -25,6 +25,7 @@
#include <linux/clockchips.h>
#include <linux/completion.h>
#include <linux/cpufreq.h>
+#include <linux/irq_work.h>
#include <linux/atomic.h>
#include <asm/smp.h>
@@ -66,6 +67,7 @@ enum ipi_msg_type {
IPI_CALL_FUNC,
IPI_CALL_FUNC_SINGLE,
IPI_CPU_STOP,
+ IPI_IRQ_WORK,
};
static DECLARE_COMPLETION(cpu_running);
@@ -448,6 +450,13 @@ void arch_send_call_function_single_ipi(int cpu)
smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);
}
+#ifdef CONFIG_IRQ_WORK
+void arch_irq_work_raise(void)
+{
+ smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK);
+}
+#endif
+
static const char *ipi_types[NR_IPI] = {
#define S(x,s) [x] = s
S(IPI_WAKEUP, "CPU wakeup interrupts"),
@@ -456,6 +465,7 @@ static const char *ipi_types[NR_IPI] = {
S(IPI_CALL_FUNC, "Function call interrupts"),
S(IPI_CALL_FUNC_SINGLE, "Single function call interrupts"),
S(IPI_CPU_STOP, "CPU stop interrupts"),
+ S(IPI_IRQ_WORK, "IRQ work interrupts"),
};
void show_ipi_list(struct seq_file *p, int prec)
@@ -565,6 +575,14 @@ void handle_IPI(int ipinr, struct pt_regs *regs)
irq_exit();
break;
+#ifdef CONFIG_IRQ_WORK
+ case IPI_IRQ_WORK:
+ irq_enter();
+ irq_work_run();
+ irq_exit();
+ break;
+#endif
+
default:
printk(KERN_CRIT "CPU%u: Unknown IPI message 0x%x\n",
cpu, ipinr);