linux-kernel - [PATCH 4.4 100/342] s390/fpu: signals vs. floating point control register

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Message-Id: <20160301234531.206988507@linuxfoundation.org>
Date:	Tue, 01 Mar 2016 23:54:16 +0000
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	<linux-kernel@...r.kernel.org>
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	<stable@...r.kernel.org>,
	Martin Schwidefsky <schwidefsky@...ibm.com>
Subject: [PATCH 4.4 100/342] s390/fpu: signals vs. floating point control register

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Martin Schwidefsky <schwidefsky@...ibm.com>

commit 1b17cb796f5d40ffa239c6926385abd83a77a49b upstream.

git commit 904818e2f229f3d94ec95f6932a6358c81e73d78
"s390/kernel: introduce fpu-internal.h with fpu helper functions"
introduced the fpregs_store / fp_regs_load helper. These function
fail to save and restore the floating pointer control registers.

The effect is that the FPC is not correctly handled on signal
delivery and signal return.

Signed-off-by: Martin Schwidefsky <schwidefsky@...ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/s390/include/asm/fpu/internal.h |    2 ++
 1 file changed, 2 insertions(+)

--- a/arch/s390/include/asm/fpu/internal.h
+++ b/arch/s390/include/asm/fpu/internal.h
@@ -48,6 +48,7 @@ static inline void convert_fp_to_vx(__ve
 static inline void fpregs_store(_s390_fp_regs *fpregs, struct fpu *fpu)
 {
 	fpregs->pad = 0;
+	fpregs->fpc = fpu->fpc;
 	if (MACHINE_HAS_VX)
 		convert_vx_to_fp((freg_t *)&fpregs->fprs, fpu->vxrs);
 	else
@@ -57,6 +58,7 @@ static inline void fpregs_store(_s390_fp
 
 static inline void fpregs_load(_s390_fp_regs *fpregs, struct fpu *fpu)
 {
+	fpu->fpc = fpregs->fpc;
 	if (MACHINE_HAS_VX)
 		convert_fp_to_vx(fpu->vxrs, (freg_t *)&fpregs->fprs);
 	else