MIPS: kernel: scalls: Skip the syscall if denied by the seccomp filter

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6399/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/kernel/scall64-o32.S

@@ -114,6 +114,8 @@ trace_a_syscall:
 	move	a0, sp
 	jal	syscall_trace_enter
 
+	bltz	v0, 2f			# seccomp failed? Skip syscall
+
 	move	t0, s0
 	RESTORE_STATIC
 	ld	a0, PT_R4(sp)		# Restore argument registers
@@ -136,7 +138,7 @@ trace_a_syscall:
 	sd	t1, PT_R0(sp)		# save it for syscall restarting
 1:	sd	v0, PT_R2(sp)		# result
 
-	j	syscall_exit
+2:	j	syscall_exit
 
 /* ------------------------------------------------------------------------ */