s390/fpu: signals vs. floating point control register

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.

Cc: stable@vger.kernel.org # 4.4
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/arch/s390/include/asm/fpu/internal.h b/arch/s390/include/asm/fpu/internal.h
index ea91ddfe54ebb901007bb625f833f7457eff0253..629c90865a073174f61fcc47268d3311db4f3a9e 100644 (file)
--- a/arch/s390/include/asm/fpu/internal.h
+++ b/arch/s390/include/asm/fpu/internal.h
@@ -40,6 +40,7 @@ static inline void convert_fp_to_vx(__vector128 *vxrs, freg_t *fprs)
 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
@@ -49,6 +50,7 @@ static inline void fpregs_store(_s390_fp_regs *fpregs, struct fpu *fpu)
 
 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