3 files changed, 70 insertions, 32 deletions

diff --git a/arch/x86/include/asm/uintr.h b/arch/x86/include/asm/uintr.h
index d48682e628d0..23246879d11a 100644
--- a/arch/x86/include/asm/uintr.h
+++ b/arch/x86/include/asm/uintr.h
@@ -63,7 +63,7 @@ void uintr_free(struct task_struct *task);
 void switch_uintr_prepare(struct task_struct *prev);
 void switch_uintr_return(void);
 
-int uintr_receiver_wait(void);
+int uintr_receiver_wait(ktime_t *expires);
 void uintr_wake_up_process(void);
 
 #else /* !CONFIG_X86_USER_INTERRUPTS */
diff --git a/arch/x86/kernel/uintr_core.c b/arch/x86/kernel/uintr_core.c
index 0074fbc0290a..831a4d4d0e93 100644
--- a/arch/x86/kernel/uintr_core.c
+++ b/arch/x86/kernel/uintr_core.c
@@ -7,6 +7,7 @@
  */
 #define pr_fmt(fmt)    "uintr: " fmt
 
+#include <linux/hrtimer.h>
 #include <linux/refcount.h>
 #include <linux/sched.h>
 #include <linux/sched/task.h>
@@ -501,17 +502,31 @@ int do_uintr_register_sender(struct uintr_receiver_info *r_info,
 	return 0;
 }
 
-int uintr_receiver_wait(void)
+/* Called when task is unregistering/exiting or timer expired */
+static void uintr_remove_task_wait(struct task_struct *task)
 {
-	struct uintr_upid_ctx *upid_ctx;
-	struct uintr_upid_ctx *upid_ctx_tmp, *tmp;
-	bool already_add = false;
+	struct uintr_upid_ctx *upid_ctx, *tmp;
 	unsigned long flags;
 
-	printk("uintr_receiver_wait\n");
+	spin_lock_irqsave(&uintr_wait_lock, flags);
+	list_for_each_entry_safe(upid_ctx, tmp, &uintr_wait_list, node) {
+		if (upid_ctx->task == task) {
+			pr_debug("wait: Removing task %d from wait\n",
+				 upid_ctx->task->pid);
+			upid_ctx->upid->nc.nv = UINTR_NOTIFICATION_VECTOR;
+			upid_ctx->waiting = false;
+			list_del(&upid_ctx->node);
+		}
+	}
+	spin_unlock_irqrestore(&uintr_wait_lock, flags);
+}
 
-	if (!is_uintr_receiver(current)) // 如果当前进程不是接收者,则返回 -EOPNOTSUPP
-		return -EOPNOTSUPP;
+void uintr_switch_to_kernel_vector(struct task_struct *t)
+{
+	struct uintr_upid_ctx *upid_ctx;
+	struct uintr_upid_ctx *upid_ctx_tmp, *tmp;
+	unsigned long flags;
+	bool already_add = false;
 
 	upid_ctx = current->thread.ui_recv->upid_ctx; // 取出当前进程的 upid_ctx
 	upid_ctx->upid->nc.nv = UINTR_KERNEL_VECTOR; // 设置 upid_ctx 的 upid->nc.nv 为内核向量
@@ -541,11 +556,45 @@ int uintr_receiver_wait(void)
 
 	printk("wait upid status: %x\n",upid_ctx->upid->nc.status);
 	printk("uintr_receiver_wait: going to sleep clear SN\n");
+}
+
+int uintr_receiver_wait(ktime_t *expires)
+{
+	struct uintr_upid_ctx *upid_ctx;
+	struct uintr_upid_ctx *upid_ctx_tmp, *tmp;
+	bool already_add = false;
+	unsigned long flags;
+
+	struct task_struct *tsk = current;
+	struct hrtimer_sleeper t;
+
+	printk("uintr_receiver_wait\n");
+
+	if (!is_uintr_receiver(current)) // 如果当前进程不是接收者,则返回 -EOPNOTSUPP
+		return -EOPNOTSUPP;
+	if (expires && *expires == 0)
+		return 0;
+
+	uintr_switch_to_kernel_vector(tsk);
+
+	hrtimer_init_sleeper_on_stack(&t, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+	hrtimer_set_expires_range_ns(&t.timer, *expires, 0);
+	hrtimer_sleeper_start_expires(&t, HRTIMER_MODE_REL);
 
 	set_current_state(TASK_INTERRUPTIBLE); // 设置为可中断的状态
-	schedule(); // 让出调度
+	if (t.task)
+		schedule();
+
+	hrtimer_cancel(&t.timer);
+	destroy_hrtimer_on_stack(&t.timer);
 
-	return -EINTR;
+	if (!t.task)
+		uintr_remove_task_wait(tsk);
+
+	__set_current_state(TASK_RUNNING); // 设置为运行状态
+	pr_debug("recv: Returned from schedule task=%d\n", current->pid);
+
+	return !t.task ? 0 : -EINTR;
 }
 
 /*
@@ -580,24 +629,6 @@ void uintr_wake_up_process(void)
 	printk("uintr_wake_up_process: done\n");
 }
 
-/* Called when task is unregistering/exiting */
-static void uintr_remove_task_wait(struct task_struct *task)
-{
-	struct uintr_upid_ctx *upid_ctx, *tmp;
-	unsigned long flags;
-
-	spin_lock_irqsave(&uintr_wait_lock, flags); // 获取全局等待锁
-	list_for_each_entry_safe(upid_ctx, tmp, &uintr_wait_list, node) { // 遍历 uintr_wait_list 
-		if (upid_ctx->task == task) { // 如果找到了当前进程
-			pr_debug("wait: Removing task %d from wait\n",
-				 upid_ctx->task->pid);
-			upid_ctx->upid->nc.nv = UINTR_NOTIFICATION_VECTOR; // 设置 upid 的 nv 为 0xec
-			upid_ctx->waiting = false; // 等待为 false
-			list_del(&upid_ctx->node); // 从链表中删除
-		}
-	}
-	spin_unlock_irqrestore(&uintr_wait_lock, flags); // 释放全局等待锁
-}
 
 // 
 int do_uintr_unregister_handler(void)
diff --git a/arch/x86/kernel/uintr_fd.c b/arch/x86/kernel/uintr_fd.c
index f2e59d445733..5e6784b50132 100644
--- a/arch/x86/kernel/uintr_fd.c
+++ b/arch/x86/kernel/uintr_fd.c
@@ -304,16 +304,23 @@ out_fdput:
 }
 
 /*
- * sys_uintr_wait - Wait for a user interrupt
+ * sys_uintr_wait - Wait for a user interrupt for the specified time
  */
-SYSCALL_DEFINE1(uintr_wait, unsigned int, flags)
+SYSCALL_DEFINE2(uintr_wait, u64, usec, unsigned int, flags)
 {
+	ktime_t expires;
+
 	if (!uintr_arch_enabled())
 		return -EOPNOTSUPP;
 
 	if (flags)
 		return -EINVAL;
 
-	/* TODO: Add a timeout option */
-	return uintr_receiver_wait(); // 主要逻辑在这了
+	if (usec == 0)
+		return 0;
+
+	/* For now, use a default timeout value of 100 usec */
+	/* For qemu 2575 is recommend*/
+	expires = usec * NSEC_PER_USEC;
+	return uintr_receiver_wait(&expires);
 }