4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Maciej W. Rozycki <redacted>

commit 006501e039eec411842bb3150c41358867d320c2 upstream.

Complement commit d614fd58a283 ("mips/ptrace: Preserve previous
registers for short regset write") and like with the PTRACE_GETREGSET
ptrace(2) request also apply a BUILD_BUG_ON check for the size of the
`elf_fpreg_t' type in the PTRACE_SETREGSET request handler.

Signed-off-by: Maciej W. Rozycki <redacted>
Fixes: d614fd58a283 ("mips/ptrace: Preserve previous registers for short regset write")
Cc: James Hogan <redacted>
Cc: Paul Burton <redacted>
Cc: Alex Smith <redacted>
Cc: Dave Martin <Dave.Martin@arm.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/17929/
Signed-off-by: Ralf Baechle <redacted>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/mips/kernel/ptrace.c |    1 +
 1 file changed, 1 insertion(+)

--- a/arch/mips/kernel/ptrace.c
+++ b/arch/mips/kernel/ptrace.c

@@ -467,6 +467,7 @@ static int fpr_get_msa(struct task_struc
 	u64 fpr_val;
 	int err;
 
+	BUILD_BUG_ON(sizeof(fpr_val) != sizeof(elf_fpreg_t));
 	for (i = 0; i < NUM_FPU_REGS; i++) {
 		fpr_val = get_fpr64(&target->thread.fpu.fpr[i], 0);
 		err = user_regset_copyout(pos, count, kbuf, ubuf,