Re: [PATCH 04/13] powerpc: Use soft_enabled_set api to update paca->soft_enabled

On Friday 16 September 2016 03:23 PM, Nicholas Piggin wrote:

On Thu, 15 Sep 2016 18:31:54 +0530
Madhavan Srinivasan [off-list ref] wrote:

quoted

Force use of soft_enabled_set() wrapper to update paca-soft_enabled
wherever possisble. Also add a new wrapper function, soft_enabled_set_return(),
added to force the paca->soft_enabled updates.

Signed-off-by: Madhavan Srinivasan <redacted>
---
  arch/powerpc/include/asm/hw_irq.h  | 14 ++++++++++++++
  arch/powerpc/include/asm/kvm_ppc.h |  2 +-
  arch/powerpc/kernel/irq.c          |  2 +-
  arch/powerpc/kernel/setup_64.c     |  4 ++--
  arch/powerpc/kernel/time.c         |  6 +++---
  5 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h
index 8fad8c24760b..f828b8f8df02 100644
--- a/arch/powerpc/include/asm/hw_irq.h
+++ b/arch/powerpc/include/asm/hw_irq.h

@@ -53,6 +53,20 @@ static inline notrace void soft_enabled_set(unsigned long enable)
  	: : "r" (enable), "i" (offsetof(struct paca_struct, soft_enabled)));
  }
  
+static inline notrace unsigned long soft_enabled_set_return(unsigned long enable)
+{
+	unsigned long flags;
+
+	asm volatile(
+		"lbz %0,%1(13); stb %2,%1(13)"
+		: "=r" (flags)
+		: "i" (offsetof(struct paca_struct, soft_enabled)),\
+		  "r" (enable)
+		: "memory");
+
+	return flags;
+}

Why do you have the "memory" clobber here while soft_enabled_set() does not?

I did change to function to include a local variable
and update the soft_enabled. But, my bad. It was in the next patch.
I should make the change here. Yes. we dont a "memory" clobber here
which is right. But, this change is not complete and I will correct it.

Maddy

Thanks,
Nick