Thread (20 messages) 20 messages, 3 authors, 2016-01-18

[PATCH V2 4/8] powerpc: Explicitly disable math features when copying thread

STALE3912d

From: Cyril Bur <hidden>
Date: 2016-01-15 05:05:37
Subsystem: linux for powerpc (32-bit and 64-bit), the rest · Maintainers: Madhavan Srinivasan, Linus Torvalds

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 <redacted>
---
 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
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