Thread (31 messages) 31 messages, 3 authors, 2016-07-28

Re: [RFC PATCH 8/9] powerpc: Support to replay PMIs

From: Nicholas Piggin <npiggin@gmail.com>
Date: 2016-07-26 05:51:07

On Mon, 25 Jul 2016 20:22:21 +0530
Madhavan Srinivasan [off-list ref] wrote:
Code to replay the Performance Monitoring Interrupts(PMI).
In the masked_interrupt handler, for PMIs we reset the MSR[EE]
and return. This is due the fact that PMIs are level triggered.
In the __check_irq_replay(), we enabled the MSR[EE] which will
fire the interrupt for us.

Patch also adds a new arch_local_irq_disable_var() variant. New
variant takes an input value to write to the paca->soft_enabled.
This will be used in following patch to implement the tri-state
value for soft-enabled.
Same comment also applies about patches being standalone
transformations that work before and after. Some of these
can be squashed together I think.

quoted hunk ↗ jump to hunk
Signed-off-by: Madhavan Srinivasan <redacted>
---
 arch/powerpc/include/asm/hw_irq.h | 14 ++++++++++++++
 arch/powerpc/kernel/irq.c         |  9 ++++++++-
 2 files changed, 22 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/hw_irq.h
b/arch/powerpc/include/asm/hw_irq.h index cc69dde6eb84..863179654452
100644 --- a/arch/powerpc/include/asm/hw_irq.h
+++ b/arch/powerpc/include/asm/hw_irq.h
@@ -81,6 +81,20 @@ static inline unsigned long
arch_local_irq_disable(void) return flags;
 }
 
+static inline unsigned long arch_local_irq_disable_var(int value)
+{
+	unsigned long flags, zero;
+
+	asm volatile(
+		"li %1,%3; lbz %0,%2(13); stb %1,%2(13)"
+		: "=r" (flags), "=&r" (zero)
+		: "i" (offsetof(struct paca_struct, soft_enabled)),\
+		  "i" (value)
+		: "memory");
+
+	return flags;
+}
arch_ function suggests it is arch implementation of a generic
kernel function or something. I think our soft interrupt levels
are just used in powerpc specific code.

The name could also be a little more descriptive.

I would have our internal function be something like

soft_irq_set_level(), and then the arch disable just sets to
the appropriate level as it does today.

The PMU disable level could be implemented in powerpc specific
header with local_irq_and_pmu_disable() or something like that.

Thanks,
Nick
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