diff options
| author | Larry Bassel <larry.bassel@linaro.org> | 2014-10-15 15:03:09 -0700 |
|---|---|---|
| committer | Larry Bassel <larry.bassel@linaro.org> | 2014-10-15 15:03:09 -0700 |
| commit | 16f8c2dfc148f67f92bcac35c2fb57f05444ee65 (patch) | |
| tree | e9351228e5faa07c143b3d6240ba0427e0b6f760 | |
| parent | 42108afdd3ce3010ed1e7ff613cc97d024807e99 (diff) | |
arm64: Support arch_irq_work_raise() via self IPIs
Backport of the following patch to LSK 3.14:
commit eb631bb5bf5b042202aaaee4a8dd8f863ba2a900
Author: Larry Bassel <larry.bassel@linaro.org>
Date: Mon May 12 16:48:51 2014 +0100
arm64: Support arch_irq_work_raise() via self IPIs
Support for arch_irq_work_raise() was missing from
arm64 (a prerequisite for FULL_NOHZ).
This patch is based on the arm32 patch ARM 7872/1.
commit bf18525fd793101df42a1344ecc48b49b62e48c9
Author: Stephen Boyd <sboyd@codeaurora.org>
Date: Tue Oct 29 20:32:56 2013 +0100
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>
Signed-off-by: Larry Bassel <larry.bassel@linaro.org>
Reviewed-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Larry Bassel <larry.bassel@linaro.org>
| -rw-r--r-- | arch/arm64/include/asm/hardirq.h | 2 | ||||
| -rw-r--r-- | arch/arm64/kernel/smp.c | 19 |
2 files changed, 20 insertions, 1 deletions
diff --git a/arch/arm64/include/asm/hardirq.h b/arch/arm64/include/asm/hardirq.h index ae4801d77514..0be67821f9ce 100644 --- a/arch/arm64/include/asm/hardirq.h +++ b/arch/arm64/include/asm/hardirq.h @@ -20,7 +20,7 @@ #include <linux/threads.h> #include <asm/irq.h> -#define NR_IPI 5 +#define NR_IPI 6 typedef struct { unsigned int __softirq_pending; diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index 9660750f34ba..6819fab9a80b 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -35,6 +35,7 @@ #include <linux/clockchips.h> #include <linux/completion.h> #include <linux/of.h> +#include <linux/irq_work.h> #include <asm/atomic.h> #include <asm/cacheflush.h> @@ -62,6 +63,7 @@ enum ipi_msg_type { IPI_CALL_FUNC_SINGLE, IPI_CPU_STOP, IPI_TIMER, + IPI_IRQ_WORK, }; /* @@ -454,6 +456,14 @@ 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) +{ + if (smp_cross_call) + smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK); +} +#endif + static const char *ipi_types[NR_IPI] = { #define S(x,s) [x - IPI_RESCHEDULE] = s S(IPI_RESCHEDULE, "Rescheduling interrupts"), @@ -461,6 +471,7 @@ static const char *ipi_types[NR_IPI] = { S(IPI_CALL_FUNC_SINGLE, "Single function call interrupts"), S(IPI_CPU_STOP, "CPU stop interrupts"), S(IPI_TIMER, "Timer broadcast interrupts"), + S(IPI_IRQ_WORK, "IRQ work interrupts"), }; void show_ipi_list(struct seq_file *p, int prec) @@ -553,6 +564,14 @@ void handle_IPI(int ipinr, struct pt_regs *regs) break; #endif +#ifdef CONFIG_IRQ_WORK + case IPI_IRQ_WORK: + irq_enter(); + irq_work_run(); + irq_exit(); + break; +#endif + default: pr_crit("CPU%u: Unknown IPI message 0x%x\n", cpu, ipinr); break; |