csky: uprobes: Restore thread.trap_no

thread.trap_no is saved in arch_uprobe_pre_xol(), it should be restored
in arch_uprobe_{post,abort}_xol() accordingly, otherwise the save operation
is meaningless, this change is similar with x86 and powerpc.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Guo Ren <guoren@kernel.org>

arch/csky/kernel/probes/uprobes.c

@@ -64,6 +64,7 @@ int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
 	struct uprobe_task *utask = current->utask;
 
 	WARN_ON_ONCE(current->thread.trap_no != UPROBE_TRAP_NR);
+	current->thread.trap_no = utask->autask.saved_trap_no;
 
 	instruction_pointer_set(regs, utask->vaddr + auprobe->insn_size);
 
@@ -101,6 +102,8 @@ void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
 {
 	struct uprobe_task *utask = current->utask;
 
+	current->thread.trap_no = utask->autask.saved_trap_no;
+
 	/*
 	 * Task has received a fatal signal, so reset back to probed
 	 * address.