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From: Cyril Bur <cyrilbur@gmail.com>
To: mikey@neuling.org, anton@samba.org, linuxppc-dev@ozlabs.org
Subject: [PATCH 4/8] powerpc: Explicitly disable math features when copying thread
Date: Wed, 18 Nov 2015 14:26:51 +1100	[thread overview]
Message-ID: <1447817215-15804-5-git-send-email-cyrilbur@gmail.com> (raw)
In-Reply-To: <1447817215-15804-1-git-send-email-cyrilbur@gmail.com>

With threads leaving the math bits enabled in their saved MSR to indicate
that the hardware is hot and a restore is not needed, children need to turn
it off as when they do get scheduled, there's no way their registers could
have been hot.

Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
---
 arch/powerpc/kernel/process.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 398f7bf..441d9e5 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1243,6 +1243,7 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
 
 		f = ret_from_fork;
 	}
+	childregs->msr &= ~(MSR_FP|MSR_VEC|MSR_VSX);
 	sp -= STACK_FRAME_OVERHEAD;
 
 	/*
-- 
2.6.2

  parent reply	other threads:[~2015-11-18  3:28 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-18  3:26 [PATCH 0/8] FP/VEC/VSX switching optimisations Cyril Bur
2015-11-18  3:26 ` [PATCH 1/8] selftests/powerpc: Test the preservation of FPU and VMX regs across syscall Cyril Bur
2015-11-23  0:23   ` Michael Neuling
2015-11-23  0:58     ` Cyril Bur
2015-11-23  1:06       ` Michael Neuling
2015-11-18  3:26 ` [PATCH 2/8] selftests/powerpc: Test preservation of FPU and VMX regs across preemption Cyril Bur
2015-11-23  0:34   ` Michael Neuling
2015-11-18  3:26 ` [PATCH 3/8] selftests/powerpc: Test FPU and VMX regs in signal ucontext Cyril Bur
2015-11-19 11:36   ` [3/8] " Michael Ellerman
2015-11-23  1:04   ` [PATCH 3/8] " Michael Neuling
2015-11-18  3:26 ` Cyril Bur [this message]
2015-11-23  1:08   ` [PATCH 4/8] powerpc: Explicitly disable math features when copying thread Michael Neuling
2015-11-23  3:20     ` Cyril Bur
2015-11-18  3:26 ` [PATCH 5/8] powerpc: Restore FPU/VEC/VSX if previously used Cyril Bur
2015-11-20 11:01   ` Michael Ellerman
2015-11-22 22:18     ` Cyril Bur
2015-11-22 23:07       ` Michael Ellerman
2015-11-23  1:29   ` Michael Neuling
2015-11-18  3:26 ` [PATCH 6/8] powerpc: Add the ability to save FPU without giving it up Cyril Bur
2015-11-18  3:26 ` [PATCH 7/8] powerpc: Add the ability to save Altivec " Cyril Bur
2015-11-18  3:26 ` [PATCH 8/8] powerpc: Add the ability to save VSX " Cyril Bur
2015-11-18 14:51 ` [PATCH 0/8] FP/VEC/VSX switching optimisations David Laight
2015-11-18 23:01   ` Cyril Bur

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