From 9dce990d2cf57b5ed4e71a9cdbd7eae4335111ff Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Tue, 24 Jan 2017 08:05:52 +0100 Subject: [PATCH] s390/ptrace: Preserve previous registers for short regset write 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. Cc: stable@vger.kernel.org Reported-by: Dave Martin Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/ptrace.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c index 7447ba509c30..12020b55887b 100644 --- a/arch/s390/kernel/ptrace.c +++ b/arch/s390/kernel/ptrace.c @@ -963,6 +963,11 @@ static int s390_fpregs_set(struct task_struct *target, 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_struct *target, 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++) -- 2.20.1