From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH] powerpc/32: indirect function call use bctrl rather than blrl in ret_from_kernel_thread
Date: Fri, 20 Aug 2021 05:16:05 +0000 (UTC) [thread overview]
Message-ID: <91b1d242525307ceceec7ef6e832bfbacdd4501b.1629436472.git.christophe.leroy@csgroup.eu> (raw)
Copied from commit 89bbe4c798bc ("powerpc/64: indirect function call
use bctrl rather than blrl in ret_from_kernel_thread")
blrl is not recommended to use as an indirect function call, as it may
corrupt the link stack predictor.
This is not a performance critical path but this should be fixed for
consistency.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/powerpc/kernel/entry_32.S | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index 0273a1349006..61fdd53cdd9a 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -161,10 +161,10 @@ ret_from_fork:
ret_from_kernel_thread:
REST_NVGPRS(r1)
bl schedule_tail
- mtlr r14
+ mtctr r14
mr r3,r15
PPC440EP_ERR42
- blrl
+ bctrl
li r3,0
b ret_from_syscall
--
2.25.0
next reply other threads:[~2021-08-20 5:16 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-20 5:16 Christophe Leroy [this message]
2021-08-20 12:15 ` [PATCH] powerpc/32: indirect function call use bctrl rather than blrl in ret_from_kernel_thread Michael Ellerman
2021-08-20 17:18 ` Segher Boessenkool
2021-08-20 18:12 ` Segher Boessenkool
2021-08-27 13:15 ` Michael Ellerman
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