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| Started by | Anna-Maria Gleixner <anna-maria@linutronix.de> |
|---|---|
| First post | 2016-04-06 10:50 +0200 |
| Last post | 2016-04-14 19:20 +0200 |
| Articles | 2 — 2 participants |
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[PATCH v2] arm64/debug: Remove superfluous SMP function call Anna-Maria Gleixner <anna-maria@linutronix.de> - 2016-04-06 10:50 +0200
Re: [PATCH v2] arm64/debug: Remove superfluous SMP function call Will Deacon <will.deacon@arm.com> - 2016-04-14 19:20 +0200
| From | Anna-Maria Gleixner <anna-maria@linutronix.de> |
|---|---|
| Date | 2016-04-06 10:50 +0200 |
| Subject | [PATCH v2] arm64/debug: Remove superfluous SMP function call |
| Message-ID | <rkRjX-1aV-5@gated-at.bofh.it> |
Since commit 1cf4f629d9d2 ("cpu/hotplug: Move online calls to
hotplugged cpu") it is ensured that callbacks of CPU_ONLINE and
CPU_DOWN_PREPARE are processed on the hotplugged CPU. Due to this SMP
function calls are no longer required.
Replace smp_call_function_single() with a direct call to
clear_os_lock(). The function writes the OSLAR register to clear OS
locking. This does not require to be called with interrupts disabled,
therefore the smp_call_function_single() calling convention is not
preserved.
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
---
arch/arm64/kernel/debug-monitors.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
--- a/arch/arm64/kernel/debug-monitors.c
+++ b/arch/arm64/kernel/debug-monitors.c
@@ -135,9 +135,8 @@ static void clear_os_lock(void *unused)
static int os_lock_notify(struct notifier_block *self,
unsigned long action, void *data)
{
- int cpu = (unsigned long)data;
if ((action & ~CPU_TASKS_FROZEN) == CPU_ONLINE)
- smp_call_function_single(cpu, clear_os_lock, NULL, 1);
+ clear_os_lock(NULL);
return NOTIFY_OK;
}
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| From | Will Deacon <will.deacon@arm.com> |
|---|---|
| Date | 2016-04-14 19:20 +0200 |
| Message-ID | <rnT5U-5uk-9@gated-at.bofh.it> |
| In reply to | #1372292 |
On Wed, Apr 06, 2016 at 10:42:28AM +0200, Anna-Maria Gleixner wrote:
> Since commit 1cf4f629d9d2 ("cpu/hotplug: Move online calls to
> hotplugged cpu") it is ensured that callbacks of CPU_ONLINE and
> CPU_DOWN_PREPARE are processed on the hotplugged CPU. Due to this SMP
> function calls are no longer required.
>
> Replace smp_call_function_single() with a direct call to
> clear_os_lock(). The function writes the OSLAR register to clear OS
> locking. This does not require to be called with interrupts disabled,
> therefore the smp_call_function_single() calling convention is not
> preserved.
>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: linux-arm-kernel@lists.infradead.org
> Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
> ---
> arch/arm64/kernel/debug-monitors.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
Applied this and the hw_breakpoint one too, thanks.
Will
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