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From: Cyril Bur <cyrilbur@gmail.com>
To: linuxppc-dev@ozlabs.org
Subject: [PATCH V2 4/8] powerpc: Explicitly disable math features when copying thread
Date: Fri, 15 Jan 2016 16:04:10 +1100	[thread overview]
Message-ID: <1452834254-22078-5-git-send-email-cyrilbur@gmail.com> (raw)
In-Reply-To: <1452834254-22078-1-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 dccc87e..e0c3d2d 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1307,6 +1307,7 @@ 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;
 
 	/*
-- 
2.7.0

  parent reply	other threads:[~2016-01-15  5:05 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-15  5:04 [PATCH V2 0/8] FP/VEC/VSX switching optimisations Cyril Bur
2016-01-15  5:04 ` [PATCH V2 1/8] selftests/powerpc: Test the preservation of FPU and VMX regs across syscall Cyril Bur
2016-01-15  5:04 ` [PATCH V2 2/8] selftests/powerpc: Test preservation of FPU and VMX regs across preemption Cyril Bur
2016-01-15  5:04 ` [PATCH V2 3/8] selftests/powerpc: Test FPU and VMX regs in signal ucontext Cyril Bur
2016-01-15  5:04 ` Cyril Bur [this message]
2016-01-15  5:42   ` [PATCH V2 4/8] powerpc: Explicitly disable math features when copying thread Michael Neuling
2016-01-15  5:54     ` Cyril Bur
2016-01-15  6:04       ` Michael Neuling
2016-01-15  5:04 ` [PATCH V2 5/8] powerpc: Restore FPU/VEC/VSX if previously used Cyril Bur
2016-01-15  6:02   ` Michael Neuling
2016-01-18  2:05     ` Cyril Bur
2016-01-15  5:04 ` [PATCH V2 6/8] powerpc: Add the ability to save FPU without giving it up Cyril Bur
2016-01-15  6:08   ` Michael Neuling
2016-01-15  7:38   ` Denis Kirjanov
2016-01-15  7:42     ` Denis Kirjanov
2016-01-15  5:04 ` [PATCH V2 7/8] powerpc: Add the ability to save Altivec " Cyril Bur
2016-01-15  5:04 ` [PATCH V2 8/8] powerpc: Add the ability to save VSX " Cyril Bur
2016-01-15  6:25   ` Michael Neuling
2016-01-18  2:10     ` Cyril Bur
2016-01-18  4:29       ` Michael Neuling

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