4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Martin Schwidefsky <schwidef...@de.ibm.com>
commit 9dce990d2cf57b5ed4e71a9cdbd7eae4335111ff upstream.
Ensure that if userspace supplies insufficient data to
PTRACE_SETREGSET to fill all the registers, the thread's old
registers are preserved.
convert_vx_to_fp() is adapted to handle only a specified number of
registers rather than unconditionally handling all of them: other
callers of this function are adapted appropriately.
Based on an initial patch by Dave Martin.
Reported-by: Dave Martin <dave.mar...@arm.com>
Signed-off-by: Martin Schwidefsky <schwidef...@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
arch/s390/kernel/ptrace.c | 8 ++++++++
1 file changed, 8 insertions(+)
--- a/arch/s390/kernel/ptrace.c
+++ b/arch/s390/kernel/ptrace.c
@@ -963,6 +963,11 @@ static int s390_fpregs_set(struct task_s
if (target == current)
save_fpu_regs();
+ if (MACHINE_HAS_VX)
+ convert_vx_to_fp(fprs, target->thread.fpu.vxrs);
+ else
+ memcpy(&fprs, target->thread.fpu.fprs, sizeof(fprs));
+
/* If setting FPC, must validate it first. */
if (count > 0 && pos < offsetof(s390_fp_regs, fprs)) {
u32 ufpc[2] = { target->thread.fpu.fpc, 0 };
@@ -1067,6 +1072,9 @@ static int s390_vxrs_low_set(struct task
if (target == current)
save_fpu_regs();
+ for (i = 0; i < __NUM_VXRS_LOW; i++)
+ vxrs[i] = *((__u64 *)(target->thread.fpu.vxrs + i) + 1);
+
rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf, vxrs, 0, -1);
if (rc == 0)
for (i = 0; i < __NUM_VXRS_LOW; i++)
