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Message-Id: <7fbae252f24ec4d30f52f57a549901fa3f799f8f.1523984745.git.christophe.leroy@c-s.fr>
Date: Tue, 17 Apr 2018 19:08:16 +0200 (CEST)
From: Christophe Leroy <christophe.leroy@....fr>
To: Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Michael Ellerman <mpe@...erman.id.au>
Cc: linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH v2 1/2] powerpc: avoid an unnecessary test and branch in
longjmp()
Doing the test at exit of the function avoids an unnecessary
test and branch inside longjmp()
Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
---
v2: Swapped both patches in the serie to reduce number of impacted lines
arch/powerpc/kernel/misc.S | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/arch/powerpc/kernel/misc.S b/arch/powerpc/kernel/misc.S
index e1f3a5d054c4..746ee0320ad4 100644
--- a/arch/powerpc/kernel/misc.S
+++ b/arch/powerpc/kernel/misc.S
@@ -74,10 +74,7 @@ _GLOBAL(setjmp)
blr
_GLOBAL(longjmp)
- PPC_LCMPI r4,0
- bne 1f
- li r4,1
-1: PPC_LL r13,4*SZL(r3)
+ PPC_LL r13,4*SZL(r3)
PPC_LL r14,5*SZL(r3)
PPC_LL r15,6*SZL(r3)
PPC_LL r16,7*SZL(r3)
@@ -102,7 +99,9 @@ _GLOBAL(longjmp)
PPC_LL r1,SZL(r3)
PPC_LL r2,2*SZL(r3)
mtlr r0
- mr r3,r4
+ mr. r3, r4
+ bnelr
+ li r3, 1
blr
_GLOBAL(current_stack_pointer)
--
2.13.3
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