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
WARNING: multiple messages have this Message-ID (diff)
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: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.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: 9+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-08-20 5:16 Christophe Leroy [this message] 2021-08-20 5:16 ` [PATCH] powerpc/32: indirect function call use bctrl rather than blrl in ret_from_kernel_thread Christophe Leroy 2021-08-20 12:15 ` Michael Ellerman 2021-08-20 12:15 ` Michael Ellerman 2021-08-20 17:18 ` Segher Boessenkool 2021-08-20 17:18 ` Segher Boessenkool 2021-08-20 18:12 ` Segher Boessenkool 2021-08-20 18:12 ` Segher Boessenkool 2021-08-27 13:15 ` Michael Ellerman
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