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[Zesty,v2,07/13] powerpc/64s: Avoid a branch for ppc_msgsnd

Message ID 20170523132748.19944-8-gwalbon@linux.vnet.ibm.com
State New
Headers show

Commit Message

Gustavo Walbon May 23, 2017, 1:27 p.m. UTC 
From: Nicholas Piggin <npiggin@gmail.com>

Buglink : http://bugs.launchpad.net/bugs/1691973

IPIs are a pretty hot path and we already have the ability to do asm feature
patching, so use it.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Change log detail]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

(cherry picked from commit a5adf282461fb6048973ca3aec590495bdbc33f1 in
linux-next)
Signed-off-by: Gustavo Walbon <gwalbon@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/dbell.h | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)
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Patch

diff --git a/arch/powerpc/include/asm/dbell.h b/arch/powerpc/include/asm/dbell.h
index 350694a1a6e5..040944659a20 100644
--- a/arch/powerpc/include/asm/dbell.h
+++ b/arch/powerpc/include/asm/dbell.h
@@ -38,10 +38,8 @@  enum ppc_dbell {
 
 static inline void _ppc_msgsnd(u32 msg)
 {
-	if (cpu_has_feature(CPU_FTR_HVMODE))
-		__asm__ __volatile__ (PPC_MSGSND(%0) : : "r" (msg));
-	else
-		__asm__ __volatile__ (PPC_MSGSNDP(%0) : : "r" (msg));
+	__asm__ __volatile__ (ASM_FTR_IFSET(PPC_MSGSND(%1), PPC_MSGSNDP(%1), %0)
+				: : "i" (CPU_FTR_HVMODE), "r" (msg));
 }
 
 /* sync before sending message */