s390/fpu: signals vs. floating point control register

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@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/s390/include/asm/fpu/internal.h b/arch/s390/include/asm/fpu/internal.h
index 2559b16da525e63427f7c82dbd1e3f2d693c7d12..17d9dcd29d45c342cce966303f2fbcc61198fcb6 100644 (file)
--- 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(__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
@@ -57,6 +58,7 @@ 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