From: Heiko Carstens <hca@linux.ibm.com>
Date: Thu, 25 Jul 2024 09:31:52 +0000 (+0200)
Subject: s390/fpu: Re-add exception handling in load_fpu_state()
X-Git-Tag: v6.11-rc2~21^2~8
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=4734406c39238cbeafe66f0060084caa3247ff53;p=thirdparty%2Fkernel%2Flinux.git

s390/fpu: Re-add exception handling in load_fpu_state()

With the recent rewrite of the fpu code exception handling for the
lfpc instruction within load_fpu_state() was erroneously removed.

Add it again to prevent that loading invalid floating point register
values cause an unhandled specification exception.

Fixes: 8c09871a950a ("s390/fpu: limit save and restore to used registers")
Cc: stable@vger.kernel.org
Reported-by: Aristeu Rozanski <aris@redhat.com>
Tested-by: Aristeu Rozanski <aris@redhat.com>
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
---

diff --git a/arch/s390/kernel/fpu.c b/arch/s390/kernel/fpu.c
index fa90bbdc5ef94..6f2e87920288a 100644
--- a/arch/s390/kernel/fpu.c
+++ b/arch/s390/kernel/fpu.c
@@ -113,7 +113,7 @@ void load_fpu_state(struct fpu *state, int flags)
 	int mask;
 
 	if (flags & KERNEL_FPC)
-		fpu_lfpc(&state->fpc);
+		fpu_lfpc_safe(&state->fpc);
 	if (!cpu_has_vx()) {
 		if (flags & KERNEL_VXR_V0V7)
 			load_fp_regs_vx(state->vxrs);