1.注解系统调用是如何发生的 2.完善对消息队列的注解

搜索 @note_pic 可以查看全部字符图
搜索 @note_why 是注者尚未看明白的地方，如果您看明白了，请告诉注者完善
搜索 @note_thinking 是注者的思考和吐槽的地方

kernel/base/core/los_task.c

@@ -570,7 +570,7 @@ STATIC INLINE VOID OsTaskSyncDestroy(UINT32 syncSignal)
 #endif
 }
 /******************************************
-等待任务的同步信号,
+等待任务的同步信号量,
 A --发送syncSignal-- > B
 B --回一个syncSignal-- > A
 如此A就知道B此时还在
@@ -587,7 +587,7 @@ LITE_OS_SEC_TEXT UINT32 OsTaskSyncWait(const LosTaskCB *taskCB)
      * triggered right at the timeout has reached, we set the timeout as double
      * of the gc peroid.
      */
-    if (LOS_SemPend(taskCB->syncSignal, OS_MP_GC_PERIOD * 2) != LOS_OK) {//发送同步信号
+    if (LOS_SemPend(taskCB->syncSignal, OS_MP_GC_PERIOD * 2) != LOS_OK) {//发送同步信号量
         ret = LOS_ERRNO_TSK_MP_SYNC_FAILED;
     }
 
@@ -1364,7 +1364,7 @@ LITE_OS_SEC_TEXT_MINOR UINT32 LOS_CurTaskPriSet(UINT16 taskPrio)
  *               taskStatus --- task status
  *               timeOut    ---  Expiry time
  * Return      : LOS_OK on success or LOS_NOK on failure
- *///任务等待,将当前任务挂到参数 list上
+ */	//任务等待,将当前任务挂到参数 list上
 UINT32 OsTaskWait(LOS_DL_LIST *list, UINT32 timeout, BOOL needSched)
 {
     LosTaskCB *runTask = NULL;
@@ -1381,7 +1381,7 @@ UINT32 OsTaskWait(LOS_DL_LIST *list, UINT32 timeout, BOOL needSched)
     }
 
     if (needSched == TRUE) {//是否需要调度
-        OsSchedResched();//申请调度,里面直接切换了任务上下文,此次任务不再往下执行了.
+        OsSchedResched();//申请调度,里面直接切换了任务上下文,至此任务不再往下执行了.
         if (runTask->taskStatus & OS_TASK_STATUS_TIMEOUT) {//这条语句是被调度再次选中时执行的,和上面的语句可能隔了很长时间,所以很可能已经超时了
             runTask->taskStatus &= ~OS_TASK_STATUS_TIMEOUT;//如果任务有timeout的标签,那么就去掉那个标签
             return LOS_ERRNO_TSK_TIMEOUT;

kernel/base/include/los_queue_pri.h

-/*
- * Copyright (c) 2013-2019, Huawei Technologies Co., Ltd. All rights reserved.
- * Copyright (c) 2020, Huawei Device Co., Ltd. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without modification,
- * are permitted provided that the following conditions are met:
- *
- * 1. Redistributions of source code must retain the above copyright notice, this list of
- *    conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright notice, this list
- *    of conditions and the following disclaimer in the documentation and/or other materials
- *    provided with the distribution.
- *
- * 3. Neither the name of the copyright holder nor the names of its contributors may be used
- *    to endorse or promote products derived from this software without specific prior written
- *    permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
- * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
- * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
- * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
- * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
- * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
- * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
- * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
- * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-#ifndef _LOS_QUEUE_PRI_H
-#define _LOS_QUEUE_PRI_H
-
-#include "los_queue.h"
-
-#ifdef __cplusplus
-#if __cplusplus
-extern "C" {
-#endif /* __cplusplus */
-#endif /* __cplusplus */
-
-typedef enum {
-    OS_QUEUE_READ = 0,	//读队列
-    OS_QUEUE_WRITE = 1,	//写队列
-    OS_QUEUE_N_RW = 2
-} QueueReadWrite;
-
-typedef enum {
-    OS_QUEUE_HEAD = 0,	//队列头部标识
-    OS_QUEUE_TAIL = 1	//队列尾部标识
-} QueueHeadTail;
-
-#define OS_QUEUE_OPERATE_TYPE(ReadOrWrite, HeadOrTail) (((UINT32)(HeadOrTail) << 1) | (ReadOrWrite))
-#define OS_QUEUE_READ_WRITE_GET(type) ((type) & 0x01U)
-#define OS_QUEUE_READ_HEAD     (OS_QUEUE_READ | (OS_QUEUE_HEAD << 1))
-#define OS_QUEUE_READ_TAIL     (OS_QUEUE_READ | (OS_QUEUE_TAIL << 1))
-#define OS_QUEUE_WRITE_HEAD    (OS_QUEUE_WRITE | (OS_QUEUE_HEAD << 1))
-#define OS_QUEUE_WRITE_TAIL    (OS_QUEUE_WRITE | (OS_QUEUE_TAIL << 1))
-#define OS_QUEUE_OPERATE_GET(type) ((type) & 0x03U)
-#define OS_QUEUE_IS_READ(type) (OS_QUEUE_READ_WRITE_GET(type) == OS_QUEUE_READ)
-#define OS_QUEUE_IS_WRITE(type) (OS_QUEUE_READ_WRITE_GET(type) == OS_QUEUE_WRITE)
-
-/**
- * @ingroup los_queue
- * Queue information block structure
- */
-typedef struct {
-    UINT8 *queueHandle; /**< Pointer to a queue handle */	//指向队列句柄的指针
-    UINT16 queueState; /**< Queue state */	//队列状态
-    UINT16 queueLen; /**< Queue length */	//队列长度
-    UINT16 queueSize; /**< Node size */		//队列大小
-    UINT32 queueID; /**< queueID */			//队列ID
-    UINT16 queueHead; /**< Node head */		//队列头部节点
-    UINT16 queueTail; /**< Node tail */		//队列尾部节点
-    UINT16 readWriteableCnt[OS_QUEUE_N_RW]; /**< Count of readable or writable resources, 0:readable, 1:writable */
-    LOS_DL_LIST readWriteList[OS_QUEUE_N_RW]; /**< the linked list to be read or written, 0:readlist, 1:writelist */
-    LOS_DL_LIST memList; /**< Pointer to the memory linked list */	//@note_why 这里尚未搞明白是啥意思 ，是共享内存吗？
-} LosQueueCB;//读写队列分离
-
-/* queue state */
-/**
- *  @ingroup los_queue
- *  Message queue state: not in use.
- */
-#define OS_QUEUE_UNUSED        0
-
-/**
- *  @ingroup los_queue
- *  Message queue state: used.
- */
-#define OS_QUEUE_INUSED        1
-
-/**
- *  @ingroup los_queue
- *  Not in use.
- */
-#define OS_QUEUE_WAIT_FOR_POOL 1
-
-/**
- *  @ingroup los_queue
- *  Normal message queue.
- */
-#define OS_QUEUE_NORMAL        0
-
-/**
- *  @ingroup los_queue
- *  Queue information control block
- */
-extern LosQueueCB *g_allQueue;
-
-/**
- * @ingroup los_queue
- * COUNT | INDEX  split bit
- */
-#define QUEUE_SPLIT_BIT        16
-/**
- * @ingroup los_queue
- * Set the queue id
- */
-#define SET_QUEUE_ID(count, queueID)    (((count) << QUEUE_SPLIT_BIT) | (queueID))
-
-/**
- * @ingroup los_queue
- * get the queue index
- */
-#define GET_QUEUE_INDEX(queueID)        ((queueID) & ((1U << QUEUE_SPLIT_BIT) - 1))
-
-/**
- * @ingroup los_queue
- * get the queue count
- */
-#define GET_QUEUE_COUNT(queueID)        ((queueID) >> QUEUE_SPLIT_BIT)
-
-/**
- * @ingroup los_queue
- * Obtain a handle of the queue that has a specified ID.
- *
- */
-#define GET_QUEUE_HANDLE(queueID)       (((LosQueueCB *)g_allQueue) + GET_QUEUE_INDEX(queueID))
-
-/**
- * @ingroup los_queue
- * Obtain the head node in a queue doubly linked list.
- */
-#define GET_QUEUE_LIST(ptr) LOS_DL_LIST_ENTRY(ptr, LosQueueCB, readWriteList[OS_QUEUE_WRITE])
-
-/**
- * @ingroup los_queue
- * @brief Alloc a stationary memory for a mail.
- *
- * @par Description:
- * This API is used to alloc a stationary memory for a mail according to queueID.
- * @attention
- * <ul>
- * <li>Do not alloc memory in unblocking modes such as interrupt.</li>
- * <li>This API cannot be called before the Huawei LiteOS is initialized.</li>
- * <li>The argument timeout is a relative time.</li>
- * </ul>
- *
- * @param queueID        [IN]        Queue ID. The value range is [1,LOSCFG_BASE_IPC_QUEUE_LIMIT].
- * @param mailPool        [IN]        The memory poll that stores the mail.
- * @param timeout        [IN]        Expiry time. The value range is [0,LOS_WAIT_FOREVER].
- *
- * @retval   #NULL                     The memory allocation is failed.
- * @retval   #pMem                     The address of alloc memory.
- * @par Dependency:
- * <ul><li>los_queue_pri.h: the header file that contains the API declaration.</li></ul>
- * @see OsQueueMailFree
- */
-extern VOID *OsQueueMailAlloc(UINT32 queueID, VOID *mailPool, UINT32 timeout);
-
-/**
- * @ingroup los_queue
- * @brief Free a stationary memory of a mail.
- *
- * @par Description:
- * This API is used to free a stationary memory for a mail according to queueID.
- * @attention
- * <ul>
- * <li>This API cannot be called before the Huawei LiteOS is initialized.</li>
- * </ul>
- *
- * @param queueID        [IN]        Queue ID. The value range is [1,LOSCFG_BASE_IPC_QUEUE_LIMIT].
- * @param mailPool        [IN]        The mail memory poll address.
- * @param mailMem         [IN]        The mail memory block address.
- *
- * @retval   #LOS_OK                                 0x00000000: The memory free successfully.
- * @retval   #OS_ERRNO_QUEUE_MAIL_HANDLE_INVALID     0x02000619: The handle of the queue passed-in when the memory
- *                                                               for the queue is being freed is invalid.
- * @retval   #OS_ERRNO_QUEUE_MAIL_PTR_INVALID        0x0200061a: The pointer to the memory to be freed is null.
- * @retval   #OS_ERRNO_QUEUE_MAIL_FREE_ERROR         0x0200061b: The memory for the queue fails to be freed.
- * @par Dependency:
- * <ul><li>los_queue_pri.h: the header file that contains the API declaration.</li></ul>
- * @see OsQueueMailAlloc
- */
-extern UINT32 OsQueueMailFree(UINT32 queueID, VOID *mailPool, VOID *mailMem);
-
-extern UINT32 OsQueueInit(VOID);
-
-#ifdef __cplusplus
-#if __cplusplus
-}
-#endif /* __cplusplus */
-#endif /* __cplusplus */
-
-#endif /* _LOS_QUEUE_PRI_H */
+/*
+ * Copyright (c) 2013-2019, Huawei Technologies Co., Ltd. All rights reserved.
+ * Copyright (c) 2020, Huawei Device Co., Ltd. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this list of
+ *    conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice, this list
+ *    of conditions and the following disclaimer in the documentation and/or other materials
+ *    provided with the distribution.
+ *
+ * 3. Neither the name of the copyright holder nor the names of its contributors may be used
+ *    to endorse or promote products derived from this software without specific prior written
+ *    permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _LOS_QUEUE_PRI_H
+#define _LOS_QUEUE_PRI_H
+
+#include "los_queue.h"
+
+#ifdef __cplusplus
+#if __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+#endif /* __cplusplus */
+
+typedef enum {
+    OS_QUEUE_READ = 0,	//读队列
+    OS_QUEUE_WRITE = 1,	//写队列
+    OS_QUEUE_N_RW = 2
+} QueueReadWrite;
+
+typedef enum {
+    OS_QUEUE_HEAD = 0,	//队列头部标识
+    OS_QUEUE_TAIL = 1	//队列尾部标识
+} QueueHeadTail;
+
+#define OS_QUEUE_OPERATE_TYPE(ReadOrWrite, HeadOrTail) (((UINT32)(HeadOrTail) << 1) | (ReadOrWrite))
+#define OS_QUEUE_READ_WRITE_GET(type) ((type) & 0x01U)
+#define OS_QUEUE_READ_HEAD     (OS_QUEUE_READ | (OS_QUEUE_HEAD << 1))
+#define OS_QUEUE_READ_TAIL     (OS_QUEUE_READ | (OS_QUEUE_TAIL << 1))
+#define OS_QUEUE_WRITE_HEAD    (OS_QUEUE_WRITE | (OS_QUEUE_HEAD << 1))
+#define OS_QUEUE_WRITE_TAIL    (OS_QUEUE_WRITE | (OS_QUEUE_TAIL << 1))
+#define OS_QUEUE_OPERATE_GET(type) ((type) & 0x03U)
+#define OS_QUEUE_IS_READ(type) (OS_QUEUE_READ_WRITE_GET(type) == OS_QUEUE_READ)
+#define OS_QUEUE_IS_WRITE(type) (OS_QUEUE_READ_WRITE_GET(type) == OS_QUEUE_WRITE)
+
+/**
+ * @ingroup los_queue
+ * Queue information block structure
+ */
+typedef struct {
+    UINT8 *queueHandle; /**< Pointer to a queue handle */	//指向队列句柄的指针
+    UINT16 queueState; /**< Queue state */	//队列状态
+    UINT16 queueLen; /**< Queue length */	//队列中消息总数的上限值,由创建时确定,不再改变
+    UINT16 queueSize; /**< Node size */		//消息节点大小,由创建时确定,不再改变,即定义了每个消息长度的上限.
+    UINT32 queueID; /**< queueID */			//队列ID
+    UINT16 queueHead; /**< Node head */		//消息头节点位置（数组下标）
+    UINT16 queueTail; /**< Node tail */		//消息尾节点位置（数组下标）
+    UINT16 readWriteableCnt[OS_QUEUE_N_RW]; /**< Count of readable or writable resources, 0:readable, 1:writable */
+											//队列中可写或可读消息数，0表示可读，1表示可写
+    LOS_DL_LIST readWriteList[OS_QUEUE_N_RW]; /**< the linked list to be read or written, 0:readlist, 1:writelist */
+											//挂的都是等待读/写消息的任务链表，0表示读消息的链表，1表示写消息的任务链表
+    LOS_DL_LIST memList; /**< Pointer to the memory linked list */	//@note_why 这里尚未搞明白是啥意思 ，是共享内存吗？
+} LosQueueCB;//读写队列分离
+
+/* queue state */
+/**
+ *  @ingroup los_queue
+ *  Message queue state: not in use.
+ */
+#define OS_QUEUE_UNUSED        0	//队列没有使用
+
+/**
+ *  @ingroup los_queue
+ *  Message queue state: used.
+ */
+#define OS_QUEUE_INUSED        1	//队列被使用
+
+/**
+ *  @ingroup los_queue
+ *  Not in use.
+ */
+#define OS_QUEUE_WAIT_FOR_POOL 1
+
+/**
+ *  @ingroup los_queue
+ *  Normal message queue.
+ */
+#define OS_QUEUE_NORMAL        0
+
+/**
+ *  @ingroup los_queue
+ *  Queue information control block
+ */
+extern LosQueueCB *g_allQueue;
+
+/**
+ * @ingroup los_queue
+ * COUNT | INDEX  split bit
+ */
+#define QUEUE_SPLIT_BIT        16
+/**
+ * @ingroup los_queue
+ * Set the queue id
+ */
+#define SET_QUEUE_ID(count, queueID)    (((count) << QUEUE_SPLIT_BIT) | (queueID))
+
+/**
+ * @ingroup los_queue
+ * get the queue index
+ */
+#define GET_QUEUE_INDEX(queueID)        ((queueID) & ((1U << QUEUE_SPLIT_BIT) - 1))
+
+/**
+ * @ingroup los_queue
+ * get the queue count
+ */
+#define GET_QUEUE_COUNT(queueID)        ((queueID) >> QUEUE_SPLIT_BIT)
+
+/**
+ * @ingroup los_queue
+ * Obtain a handle of the queue that has a specified ID.
+ *
+ */
+#define GET_QUEUE_HANDLE(queueID)       (((LosQueueCB *)g_allQueue) + GET_QUEUE_INDEX(queueID))
+
+/**
+ * @ingroup los_queue
+ * Obtain the head node in a queue doubly linked list.
+ */
+#define GET_QUEUE_LIST(ptr) LOS_DL_LIST_ENTRY(ptr, LosQueueCB, readWriteList[OS_QUEUE_WRITE])
+
+/**
+ * @ingroup los_queue
+ * @brief Alloc a stationary memory for a mail.
+ *
+ * @par Description:
+ * This API is used to alloc a stationary memory for a mail according to queueID.
+ * @attention
+ * <ul>
+ * <li>Do not alloc memory in unblocking modes such as interrupt.</li>
+ * <li>This API cannot be called before the Huawei LiteOS is initialized.</li>
+ * <li>The argument timeout is a relative time.</li>
+ * </ul>
+ *
+ * @param queueID        [IN]        Queue ID. The value range is [1,LOSCFG_BASE_IPC_QUEUE_LIMIT].
+ * @param mailPool        [IN]        The memory poll that stores the mail.
+ * @param timeout        [IN]        Expiry time. The value range is [0,LOS_WAIT_FOREVER].
+ *
+ * @retval   #NULL                     The memory allocation is failed.
+ * @retval   #pMem                     The address of alloc memory.
+ * @par Dependency:
+ * <ul><li>los_queue_pri.h: the header file that contains the API declaration.</li></ul>
+ * @see OsQueueMailFree
+ */
+extern VOID *OsQueueMailAlloc(UINT32 queueID, VOID *mailPool, UINT32 timeout);
+
+/**
+ * @ingroup los_queue
+ * @brief Free a stationary memory of a mail.
+ *
+ * @par Description:
+ * This API is used to free a stationary memory for a mail according to queueID.
+ * @attention
+ * <ul>
+ * <li>This API cannot be called before the Huawei LiteOS is initialized.</li>
+ * </ul>
+ *
+ * @param queueID        [IN]        Queue ID. The value range is [1,LOSCFG_BASE_IPC_QUEUE_LIMIT].
+ * @param mailPool        [IN]        The mail memory poll address.
+ * @param mailMem         [IN]        The mail memory block address.
+ *
+ * @retval   #LOS_OK                                 0x00000000: The memory free successfully.
+ * @retval   #OS_ERRNO_QUEUE_MAIL_HANDLE_INVALID     0x02000619: The handle of the queue passed-in when the memory
+ *                                                               for the queue is being freed is invalid.
+ * @retval   #OS_ERRNO_QUEUE_MAIL_PTR_INVALID        0x0200061a: The pointer to the memory to be freed is null.
+ * @retval   #OS_ERRNO_QUEUE_MAIL_FREE_ERROR         0x0200061b: The memory for the queue fails to be freed.
+ * @par Dependency:
+ * <ul><li>los_queue_pri.h: the header file that contains the API declaration.</li></ul>
+ * @see OsQueueMailAlloc
+ */
+extern UINT32 OsQueueMailFree(UINT32 queueID, VOID *mailPool, VOID *mailMem);
+
+extern UINT32 OsQueueInit(VOID);
+
+#ifdef __cplusplus
+#if __cplusplus
+}
+#endif /* __cplusplus */
+#endif /* __cplusplus */
+
+#endif /* _LOS_QUEUE_PRI_H */

kernel/base/include/los_signal.h

@@ -45,7 +45,11 @@ extern "C" {
 #endif /* __cplusplus */
 /********************************************
 https://www.cnblogs.com/hoys/archive/2012/08/19/2646377.html
-信号本质:用于进程之间的异步通信
+
+信号是Linux系统中用于进程间互相通信或者操作的一种机制，信号可以在任何时候发给某一进程，而无需知道该进程的状态。
+如果该进程当前并未处于执行状态，则该信号就由内核保存起来，直到该进程被调度执行并传递给它为止。
+如果一个信号被进程设置为阻塞，则该信号的传递被延迟，直到其阻塞被取消时才被传递给进程。
+
 软中断信号（signal，又简称为信号）用来通知进程发生了异步事件。在软件层次上是对中断机制的一种模拟，
 在原理上，一个进程收到一个信号与处理器收到一个中断请求可以说是一样的。信号是进程间通信机制中唯一
 的异步通信机制，一个进程不必通过任何操作来等待信号的到达，事实上，进程也不知道信号到底什么时候到达。
@@ -181,7 +185,7 @@ struct sigpendq {
 };
 typedef struct sigpendq sigpendq_t;
 
-struct sq_queue_s {
+struct sq_queue_s {//信号队列
     sq_entry_t *head;
     sq_entry_t *tail;
 };
@@ -204,19 +208,19 @@ typedef struct {//任务中断上下文
 
 typedef struct {//信号切换上下文
     TASK_IRQ_CONTEXT
-    unsigned int R7;
-    unsigned int count;
+    unsigned int R7;	//存放系统调用的ID
+    unsigned int count;	//信号上下文的数量
 } sig_switch_context;
 
 typedef struct {//信号控制块(描述符)
     sigset_t sigFlag;
-    sigset_t sigPendFlag;
+    sigset_t sigPendFlag;	//信号阻塞标签集,记录因哪些信号被阻塞
     sigset_t sigprocmask; /* Signals that are blocked            */	//进程屏蔽了哪些信号
     sq_queue_t sigactionq;	//信号捕捉队列					
     LOS_DL_LIST waitList;	//等待链表,上面挂的可是等待信号到来的任务, 请查找 OsTaskWait(&sigcb->waitList, timeout, TRUE)	理解						
-    sigset_t sigwaitmask; /* Waiting for pending signals         */	//等待挂起的信号,意思就是位信号来了都要处理,比如 SIGKILL,SIGSTOP信号
+    sigset_t sigwaitmask; /* Waiting for pending signals         */	//任务在等待某某信号的掩码
     siginfo_t sigunbinfo; /* Signal info when task unblocked     */	//任务解除阻止时的信号信息
-    sig_switch_context context;	//信号切换上下文,用于保存切换现场								
+    sig_switch_context context;	//信号切换上下文, 用于保存切换现场, 比如发生系统调用时的返回,涉及同一个任务的两个栈进行切换							
 } sig_cb;
 
 #define SIGEV_THREAD_ID 4

kernel/base/ipc/los_signal.c

@@ -86,11 +86,11 @@ int OsTcbDispatch(LosTaskCB *stcb, siginfo_t *info)
     masked = (bool)OsSigIsMember(&sigcb->sigprocmask, info->si_signo);//@note_thinking 这里还有 masked= -1的情况要处理!!!
     if (masked) {//集合中已有该信号
         /* If signal is in wait list and mask list, need unblock it */ //如果信号在等待列表和掩码列表中，需要解除阻止
-        if (!LOS_ListEmpty(&sigcb->waitList) && OsSigIsMember(&sigcb->sigwaitmask, info->si_signo)) {//等待
-            OsTaskWake(stcb);
-            OsSigEmptySet(&sigcb->sigwaitmask);
+        if (!LOS_ListEmpty(&sigcb->waitList) && OsSigIsMember(&sigcb->sigwaitmask, info->si_signo)) {//waitList上挂的都是task,sigwaitmask表示是否在等si_signo
+            OsTaskWake(stcb);//唤醒任务,从阻塞状态变成就绪态
+            OsSigEmptySet(&sigcb->sigwaitmask);//将sigwaitmask清空,都已经变成就绪状态了,当然就没有要等待的信号了.
         } else {
-            OsSigAddSet(&sigcb->sigPendFlag, info->si_signo);
+            OsSigAddSet(&sigcb->sigPendFlag, info->si_signo);//
         }
     } else {//
         /* unmasked signal actions */
@@ -409,7 +409,7 @@ EXIT:
     SCHEDULER_UNLOCK(intSave);
     return ret;
 }
-
+//添加信号到指定信号集
 int OsSigAddSet(sigset_t *set, int signo)
 {
     /* Verify the signal */
@@ -419,11 +419,11 @@ int OsSigAddSet(sigset_t *set, int signo)
         /* In musl, sig No bits 00000100 present sig No 3, but  1<< 3 = 00001000, so signo needs minus 1 */
         signo -= 1;
         /* Add the signal to the set */
-        *set |= SIGNO2SET((unsigned int)signo);
+        *set |= SIGNO2SET((unsigned int)signo);//填充信号集
         return LOS_OK;
     }
 }
-//
+//获取当前进程的阻塞信号集
 int OsSigPending(sigset_t *set)
 {
     LosTaskCB *tcb = NULL;
@@ -435,7 +435,7 @@ int OsSigPending(sigset_t *set)
 
     SCHEDULER_LOCK(intSave);
     tcb = OsCurrTaskGet();
-    *set = tcb->sig.sigPendFlag;
+    *set = tcb->sig.sigPendFlag;//因何而被阻塞
     SCHEDULER_UNLOCK(intSave);
     return LOS_OK;
 }
@@ -484,7 +484,7 @@ int OsSigTimedWaitNoLock(sigset_t *set, siginfo_t *info, unsigned int timeout)
     }
     return ret;
 }
-//
+//让当前任务等待的信号
 int OsSigTimedWait(sigset_t *set, siginfo_t *info, unsigned int timeout)
 {
     int ret;
@@ -492,12 +492,12 @@ int OsSigTimedWait(sigset_t *set, siginfo_t *info, unsigned int timeout)
 
     SCHEDULER_LOCK(intSave);
 
-    ret = OsSigTimedWaitNoLock(set, info, timeout);
+    ret = OsSigTimedWaitNoLock(set, info, timeout);//以不加锁的方式等待
 
     SCHEDULER_UNLOCK(intSave);
     return ret;
 }
-
+//让当前任务暂停的信号
 int OsPause(void)
 {
     LosTaskCB *spcb = NULL;
@@ -507,7 +507,7 @@ int OsPause(void)
     oldSigprocmask = spcb->sig.sigprocmask;
     return OsSigSuspend(&oldSigprocmask);
 }
-//暂停信号
+//让当前任务暂停的信号
 int OsSigSuspend(const sigset_t *set)
 {
     unsigned int intSave;
@@ -568,7 +568,9 @@ int OsSigAction(int sig, const sigaction_t *act, sigaction_t *oact)
 
     return LOS_OK;
 }
-//保存信号现场
+/**********************************************
+产生系统调用时,也就是软中断时,保存用户栈寄存器现场信息
+**********************************************/
 void OsSaveSignalContext(unsigned int *sp)
 {
     UINTPTR sigHandler;
@@ -581,26 +583,26 @@ void OsSaveSignalContext(unsigned int *sp)
     OS_RETURN_IF_VOID(sp == NULL);
     cpsr = OS_SYSCALL_GET_CPSR(sp);
 
-    OS_RETURN_IF_VOID(((cpsr & CPSR_MASK_MODE) != CPSR_USER_MODE));
+    OS_RETURN_IF_VOID(((cpsr & CPSR_MASK_MODE) != CPSR_USER_MODE));//必须在用户模式下保存
     SCHEDULER_LOCK(intSave);
     task = OsCurrTaskGet();
     process = OsCurrProcessGet();
-    sigcb = &task->sig;
+    sigcb = &task->sig;//获取任务的信号控制块
 
-    if ((sigcb->context.count == 0) && ((sigcb->sigFlag != 0) || (process->sigShare != 0))) {
+    if ((sigcb->context.count == 0) && ((sigcb->sigFlag != 0) || (process->sigShare != 0))) {//未保存上下文且关注了信号
         sigHandler = OsGetSigHandler();
-        if (sigHandler == 0) {
+        if (sigHandler == 0) {//信号没有注册
             sigcb->sigFlag = 0;
             process->sigShare = 0;
             SCHEDULER_UNLOCK(intSave);
             PRINT_ERR("The signal processing function for the current process pid =%d is NULL!\n", task->processID);
             return;
         }
-        /* One pthread do the share signal */
-        sigcb->sigFlag |= process->sigShare;
+        /* One pthread do the share signal */ 
+        sigcb->sigFlag |= process->sigShare;//记录由一个线程执行可进程的共享信号,这些恢复上下文时就找到对应的任务
         unsigned int signo = (unsigned int)FindFirstSetedBit(sigcb->sigFlag) + 1;
         OsProcessExitCodeSignalSet(process, signo);
-        sigcb->context.CPSR = cpsr;
+        sigcb->context.CPSR = cpsr;		//保存当前各寄存器的信息
         sigcb->context.PC = sp[REG_PC];
         sigcb->context.USP = sp[REG_SP];
         sigcb->context.ULR = sp[REG_LR];
@@ -610,17 +612,18 @@ void OsSaveSignalContext(unsigned int *sp)
         sigcb->context.R3 = sp[REG_R3];
         sigcb->context.R7 = sp[REG_R7];
         sigcb->context.R12 = sp[REG_R12];
-        sp[REG_PC] = sigHandler;
-        sp[REG_R0] = signo;
-        sp[REG_R1] = (unsigned int)(UINTPTR)(sigcb->sigunbinfo.si_value.sival_ptr);
+        sp[REG_PC] = sigHandler;//下一个要执行的函数,信号注册函数
+        sp[REG_R0] = signo;		//信号注册函数参数
+        sp[REG_R1] = (unsigned int)(UINTPTR)(sigcb->sigunbinfo.si_value.sival_ptr); //@note_why 这里看明白,是干啥子用的?
         /* sig No bits 00000100 present sig No 3, but  1<< 3 = 00001000, so signo needs minus 1 */
         sigcb->sigFlag ^= 1ULL << (signo - 1);
-        sigcb->context.count++;
+        sigcb->context.count++;	//代表已保存
     }
 
     SCHEDULER_UNLOCK(intSave);
 }
-//保存信号中断现场
+//发生硬中断时,需保存用户态的用户栈现场,多了一个参数 R7寄存器
+//汇编调用 见于 los_dispatch.S | 254行:    BL      OsSaveSignalContextIrq
 void OsSaveSignalContextIrq(unsigned int *sp, unsigned int r7)
 {
     UINTPTR sigHandler;
@@ -633,7 +636,7 @@ void OsSaveSignalContextIrq(unsigned int *sp, unsigned int r7)
 
     OS_RETURN_IF_VOID(sp == NULL);
     cpsr = context->CPSR;
-    OS_RETURN_IF_VOID(((cpsr & CPSR_MASK_MODE) != CPSR_USER_MODE));
+    OS_RETURN_IF_VOID(((cpsr & CPSR_MASK_MODE) != CPSR_USER_MODE));//必须在用户模式下保存用户栈信息
 
     SCHEDULER_LOCK(intSave);
     task = OsCurrTaskGet();
@@ -651,7 +654,7 @@ void OsSaveSignalContextIrq(unsigned int *sp, unsigned int r7)
         sigcb->sigFlag |= process->sigShare;
         unsigned int signo = (unsigned int)FindFirstSetedBit(sigcb->sigFlag) + 1;
         OsProcessExitCodeSignalSet(process, signo);
-        (VOID)memcpy_s(&sigcb->context.R0, sizeof(TaskIrqDataSize), &context->R0, sizeof(TaskIrqDataSize));
+        (VOID)memcpy_s(&sigcb->context.R0, sizeof(TaskIrqDataSize), &context->R0, sizeof(TaskIrqDataSize));//note_why 为何此处和OsSaveSignalContext的处理不一致?
         sigcb->context.R7 = r7;
         context->PC = sigHandler;
         context->R0 = signo;
@@ -662,7 +665,13 @@ void OsSaveSignalContextIrq(unsigned int *sp, unsigned int r7)
     }
     SCHEDULER_UNLOCK(intSave);
 }
-//恢复信号上下文
+/****************************************************
+恢复信号上下文,由系统调用之__NR_sigreturn产生,这是一个内部产生的系统调用.
+为什么要恢复呢?
+因为系统调用的执行由任务内核态完成,使用的栈也是内核栈,CPU相关寄存器记录的都是内核栈的内容,
+而系统调用完成后,需返回任务的用户栈执行,这时需将CPU各寄存器回到用户态现场
+所以函数的功能就变成了还原寄存器的值
+****************************************************/
 void OsRestorSignalContext(unsigned int *sp)
 {
     LosTaskCB *task = NULL; /* Do not adjust this statement */
@@ -672,28 +681,28 @@ void OsRestorSignalContext(unsigned int *sp)
 
     SCHEDULER_LOCK(intSave);
     task = OsCurrTaskGet();
-    sigcb = &task->sig;
+    sigcb = &task->sig;//获取当前任务信号控制块
 
-    if (sigcb->context.count != 1) {
+    if (sigcb->context.count != 1) {//必须之前保存过,才能被恢复
         SCHEDULER_UNLOCK(intSave);
         PRINT_ERR("sig error count : %d\n", sigcb->context.count);
         return;
     }
 
-    process = OsCurrProcessGet();
-    sp[REG_PC] = sigcb->context.PC;
-    OS_SYSCALL_SET_CPSR(sp, sigcb->context.CPSR);
-    sp[REG_SP] = sigcb->context.USP;
-    sp[REG_LR] = sigcb->context.ULR;
+    process = OsCurrProcessGet();//获取当前进程
+    sp[REG_PC] = sigcb->context.PC;//指令寄存器
+    OS_SYSCALL_SET_CPSR(sp, sigcb->context.CPSR);//重置程序状态寄存器
+    sp[REG_SP] = sigcb->context.USP;//堆栈指针, USP指的是 用户态的堆栈,即将回到用户栈继续运行
+    sp[REG_LR] = sigcb->context.ULR;//连接寄存器
     sp[REG_R0] = sigcb->context.R0;
     sp[REG_R1] = sigcb->context.R1;
     sp[REG_R2] = sigcb->context.R2;
     sp[REG_R3] = sigcb->context.R3;
     sp[REG_R7] = sigcb->context.R7;
     sp[REG_R12] = sigcb->context.R12;
-    sigcb->context.count--;
-    process->sigShare = 0;
-    OsProcessExitCodeSignalClear(process);
+    sigcb->context.count--;	//信号上下文的数量回到减少
+    process->sigShare = 0;	//回到用户态,信号共享清0
+    OsProcessExitCodeSignalClear(process);//清空进程退出码
     SCHEDULER_UNLOCK(intSave);
 }
 

kernel/include/los_sys.h

-/*
- * Copyright (c) 2013-2019, Huawei Technologies Co., Ltd. All rights reserved.
- * Copyright (c) 2020, Huawei Device Co., Ltd. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without modification,
- * are permitted provided that the following conditions are met:
- *
- * 1. Redistributions of source code must retain the above copyright notice, this list of
- *    conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright notice, this list
- *    of conditions and the following disclaimer in the documentation and/or other materials
- *    provided with the distribution.
- *
- * 3. Neither the name of the copyright holder nor the names of its contributors may be used
- *    to endorse or promote products derived from this software without specific prior written
- *    permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
- * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
- * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
- * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
- * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
- * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
- * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
- * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
- * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-/**
- * @defgroup los_sys System time
- * @ingroup kernel
- */
-
-#ifndef _LOS_SYS_H
-#define _LOS_SYS_H
-
-#include "los_base.h"
-#include "los_hwi.h"
-#include "los_hw.h"
-
-#ifdef __cplusplus
-#if __cplusplus
-extern "C" {
-#endif /* __cplusplus */
-#endif /* __cplusplus */
-
-/**
- * @ingroup los_sys
- * System time basic function error code: Null pointer.
- *
- * Value: 0x02000010
- *
- * Solution: Check whether the input parameter is null.
- */
-#define LOS_ERRNO_SYS_PTR_NULL                 LOS_ERRNO_OS_ERROR(LOS_MOD_SYS, 0x10)
-
-/**
- * @ingroup los_sys
- * System time basic function error code: Invalid system clock configuration.
- *
- * Value: 0x02000011
- *
- * Solution: Configure a valid system clock in los_config.h.
- */
-#define LOS_ERRNO_SYS_CLOCK_INVALID            LOS_ERRNO_OS_ERROR(LOS_MOD_SYS, 0x11)
-
-/**
- * @ingroup los_sys
- * System time basic function error code: This error code is not in use temporarily.
- *
- * Value: 0x02000012
- *
- * Solution: None.
- */
-#define LOS_ERRNO_SYS_MAXNUMOFCORES_IS_INVALID LOS_ERRNO_OS_ERROR(LOS_MOD_SYS, 0x12)
-
-/**
- * @ingroup los_sys
- * System time error code: This error code is not in use temporarily.
- *
- * Value: 0x02000013
- *
- * Solution: None.
- */
-#define LOS_ERRNO_SYS_PERIERRCOREID_IS_INVALID LOS_ERRNO_OS_ERROR(LOS_MOD_SYS, 0x13)
-
-/**
- * @ingroup los_sys
- * System time error code: This error code is not in use temporarily.
- *
- * Value: 0x02000014
- *
- * Solution: None.
- */
-#define LOS_ERRNO_SYS_HOOK_IS_FULL             LOS_ERRNO_OS_ERROR(LOS_MOD_SYS, 0x14)
-
-/**
- * @ingroup los_typedef
- * system time structure.
- */
-typedef struct tagSysTime {
-    UINT16 uwYear;   /**< value 1970 ~ 2038 or 1970 ~ 2100 */
-    UINT8 ucMonth;   /**< value 1 - 12 */
-    UINT8 ucDay;     /**< value 1 - 31 */
-    UINT8 ucHour;    /**< value 0 - 23 */
-    UINT8 ucMinute;  /**< value 0 - 59 */
-    UINT8 ucSecond;  /**< value 0 - 59 */
-    UINT8 ucWeek;    /**< value 0 - 6  */
-} SYS_TIME_S;
-
-/**
- * @ingroup los_sys
- * @brief Obtain the number of Ticks.
- *
- * @par Description:
- * This API is used to obtain the number of Ticks.
- * @attention
- * <ul>
- * <li>None</li>
- * </ul>
- *
- * @param  None
- *
- * @retval UINT64 The number of Ticks.
- * @par Dependency:
- * <ul><li>los_sys.h: the header file that contains the API declaration.</li></ul>
- * @see None
- */
-extern UINT64 LOS_TickCountGet(VOID);
-
-/**
- * @ingroup los_sys
- * @brief Obtain the number of cycles in one second.
- *
- * @par Description:
- * This API is used to obtain the number of cycles in one second.
- * @attention
- * <ul>
- * <li>None</li>
- * </ul>
- *
- * @param  None
- *
- * @retval UINT32 Number of cycles obtained in one second.
- * @par Dependency:
- * <ul><li>los_sys.h: the header file that contains the API declaration.</li></ul>
- * @see None
- */
-extern UINT32 LOS_CyclePerTickGet(VOID);
-
-/**
- * @ingroup los_sys
- * @brief Convert Ticks to milliseconds.
- *
- * @par Description:
- * This API is used to convert Ticks to milliseconds.
- * @attention
- * <ul>
- * <li>The number of milliseconds obtained through the conversion is 32-bit.</li>
- * </ul>
- *
- * @param  tick  [IN] Number of Ticks. The value range is (0,OS_SYS_CLOCK).
- *
- * @retval UINT32 Number of milliseconds obtained through the conversion. Ticks are successfully converted to
- * milliseconds.
- * @par  Dependency:
- * <ul><li>los_sys.h: the header file that contains the API declaration.</li></ul>
- * @see LOS_MS2Tick
- */
-extern UINT32 LOS_Tick2MS(UINT32 tick);
-
-/**
- * @ingroup los_sys
- * @brief Convert milliseconds to Ticks.
- *
- * @par Description:
- * This API is used to convert milliseconds to Ticks.
- * @attention
- * <ul>
- * <li>If the parameter passed in is equal to 0xFFFFFFFF, the retval is 0xFFFFFFFF. Pay attention to the value to be
- * converted because data possibly overflows.</li>
- * </ul>
- *
- * @param  millisec  [IN] Number of milliseconds.
- *
- * @retval UINT32 Number of Ticks obtained through the conversion.
- * @par Dependency:
- * <ul><li>los_sys.h: the header file that contains the API declaration.</li></ul>
- * @see LOS_Tick2MS
- */
-extern UINT32 LOS_MS2Tick(UINT32 millisec);
-
-#ifdef __cplusplus
-#if __cplusplus
-}
-#endif /* __cplusplus */
-#endif /* __cplusplus */
-
-#endif /* _LOS_SYS_H */
+/*
+ * Copyright (c) 2013-2019, Huawei Technologies Co., Ltd. All rights reserved.
+ * Copyright (c) 2020, Huawei Device Co., Ltd. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this list of
+ *    conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice, this list
+ *    of conditions and the following disclaimer in the documentation and/or other materials
+ *    provided with the distribution.
+ *
+ * 3. Neither the name of the copyright holder nor the names of its contributors may be used
+ *    to endorse or promote products derived from this software without specific prior written
+ *    permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/**
+ * @defgroup los_sys System time
+ * @ingroup kernel
+ */
+
+#ifndef _LOS_SYS_H
+#define _LOS_SYS_H
+
+#include "los_base.h"
+#include "los_hwi.h"
+#include "los_hw.h"
+
+#ifdef __cplusplus
+#if __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+#endif /* __cplusplus */
+//定义所有的系统调用的ID ..\third_party\musl\kernel\obj\include\bits\syscall.h
+
+/**
+ * @ingroup los_sys
+ * System time basic function error code: Null pointer.
+ *
+ * Value: 0x02000010
+ *
+ * Solution: Check whether the input parameter is null.
+ */
+#define LOS_ERRNO_SYS_PTR_NULL                 LOS_ERRNO_OS_ERROR(LOS_MOD_SYS, 0x10)
+
+/**
+ * @ingroup los_sys
+ * System time basic function error code: Invalid system clock configuration.
+ *
+ * Value: 0x02000011
+ *
+ * Solution: Configure a valid system clock in los_config.h.
+ */
+#define LOS_ERRNO_SYS_CLOCK_INVALID            LOS_ERRNO_OS_ERROR(LOS_MOD_SYS, 0x11)
+
+/**
+ * @ingroup los_sys
+ * System time basic function error code: This error code is not in use temporarily.
+ *
+ * Value: 0x02000012
+ *
+ * Solution: None.
+ */
+#define LOS_ERRNO_SYS_MAXNUMOFCORES_IS_INVALID LOS_ERRNO_OS_ERROR(LOS_MOD_SYS, 0x12)
+
+/**
+ * @ingroup los_sys
+ * System time error code: This error code is not in use temporarily.
+ *
+ * Value: 0x02000013
+ *
+ * Solution: None.
+ */
+#define LOS_ERRNO_SYS_PERIERRCOREID_IS_INVALID LOS_ERRNO_OS_ERROR(LOS_MOD_SYS, 0x13)
+
+/**
+ * @ingroup los_sys
+ * System time error code: This error code is not in use temporarily.
+ *
+ * Value: 0x02000014
+ *
+ * Solution: None.
+ */
+#define LOS_ERRNO_SYS_HOOK_IS_FULL             LOS_ERRNO_OS_ERROR(LOS_MOD_SYS, 0x14)
+
+/**
+ * @ingroup los_typedef
+ * system time structure.
+ */
+typedef struct tagSysTime {
+    UINT16 uwYear;   /**< value 1970 ~ 2038 or 1970 ~ 2100 */
+    UINT8 ucMonth;   /**< value 1 - 12 */
+    UINT8 ucDay;     /**< value 1 - 31 */
+    UINT8 ucHour;    /**< value 0 - 23 */
+    UINT8 ucMinute;  /**< value 0 - 59 */
+    UINT8 ucSecond;  /**< value 0 - 59 */
+    UINT8 ucWeek;    /**< value 0 - 6  */
+} SYS_TIME_S;
+
+/**
+ * @ingroup los_sys
+ * @brief Obtain the number of Ticks.
+ *
+ * @par Description:
+ * This API is used to obtain the number of Ticks.
+ * @attention
+ * <ul>
+ * <li>None</li>
+ * </ul>
+ *
+ * @param  None
+ *
+ * @retval UINT64 The number of Ticks.
+ * @par Dependency:
+ * <ul><li>los_sys.h: the header file that contains the API declaration.</li></ul>
+ * @see None
+ */
+extern UINT64 LOS_TickCountGet(VOID);
+
+/**
+ * @ingroup los_sys
+ * @brief Obtain the number of cycles in one second.
+ *
+ * @par Description:
+ * This API is used to obtain the number of cycles in one second.
+ * @attention
+ * <ul>
+ * <li>None</li>
+ * </ul>
+ *
+ * @param  None
+ *
+ * @retval UINT32 Number of cycles obtained in one second.
+ * @par Dependency:
+ * <ul><li>los_sys.h: the header file that contains the API declaration.</li></ul>
+ * @see None
+ */
+extern UINT32 LOS_CyclePerTickGet(VOID);
+
+/**
+ * @ingroup los_sys
+ * @brief Convert Ticks to milliseconds.
+ *
+ * @par Description:
+ * This API is used to convert Ticks to milliseconds.
+ * @attention
+ * <ul>
+ * <li>The number of milliseconds obtained through the conversion is 32-bit.</li>
+ * </ul>
+ *
+ * @param  tick  [IN] Number of Ticks. The value range is (0,OS_SYS_CLOCK).
+ *
+ * @retval UINT32 Number of milliseconds obtained through the conversion. Ticks are successfully converted to
+ * milliseconds.
+ * @par  Dependency:
+ * <ul><li>los_sys.h: the header file that contains the API declaration.</li></ul>
+ * @see LOS_MS2Tick
+ */
+extern UINT32 LOS_Tick2MS(UINT32 tick);
+
+/**
+ * @ingroup los_sys
+ * @brief Convert milliseconds to Ticks.
+ *
+ * @par Description:
+ * This API is used to convert milliseconds to Ticks.
+ * @attention
+ * <ul>
+ * <li>If the parameter passed in is equal to 0xFFFFFFFF, the retval is 0xFFFFFFFF. Pay attention to the value to be
+ * converted because data possibly overflows.</li>
+ * </ul>
+ *
+ * @param  millisec  [IN] Number of milliseconds.
+ *
+ * @retval UINT32 Number of Ticks obtained through the conversion.
+ * @par Dependency:
+ * <ul><li>los_sys.h: the header file that contains the API declaration.</li></ul>
+ * @see LOS_Tick2MS
+ */
+extern UINT32 LOS_MS2Tick(UINT32 millisec);
+
+#ifdef __cplusplus
+#if __cplusplus
+}
+#endif /* __cplusplus */
+#endif /* __cplusplus */
+
+#endif /* _LOS_SYS_H */

syscall/ipc_syscall.c

@@ -37,7 +37,26 @@
 #include "user_copy.h"
 #include "los_signal.h"
 #include "los_strncpy_from_user.h"
-//创建和打开一个posix消息队列
+/********************************************************
+本文说明:系统调用|IPC
+IPC（Inter-Process Communication，进程间通信）
+每个进程各自有不同的用户地址空间，进程之间地址保护,相互隔离,任何一个进程的信息在另一个进程中都看不到，
+所以进程之间要交换数据必须通过内核，在内核中开辟一块缓冲区，进程A把数据从用户空间拷到内核缓冲区，
+进程B再从内核缓冲区把数据读走，
+
+IPC实现方式之消息队列:
+消息队列特点总结：
+（1）消息队列是消息的链表,具有特定的格式,存放在内存中并由消息队列标识符标识.
+（2）消息队列允许一个或多个进程向它写入与读取消息.
+（3）管道和消息队列的通信数据都是先进先出的原则。
+（4）消息队列可以实现消息的随机查询,消息不一定要以先进先出的次序读取,也可以按消息的类型读取.比FIFO更有优势。
+（5）消息队列克服了信号承载信息量少，管道只能承载无格式字节流以及缓冲区大小受限等缺点。
+（6）目前主要有两种类型的消息队列：POSIX消息队列以及System V消息队列，System V消息队列是随内核持续的，
+	 只有在内核重起或者人工删除时，该消息队列才会被删除。
+	 
+鸿蒙liteos 支持POSIX消息队列并加入了一种自研的消息队列 liteipc,此处重点讲 posix消息队列
+********************************************************/
+//打开一个消息队列,封装了posix接口
 mqd_t SysMqOpen(const char *mqName, int openFlag, mode_t mode, struct mq_attr *attr)
 {
     mqd_t ret;
@@ -48,7 +67,7 @@ mqd_t SysMqOpen(const char *mqName, int openFlag, mode_t mode, struct mq_attr *a
     if (retValue < 0) {
         return retValue;
     }
-    ret = mq_open(kMqName, openFlag, mode, attr);
+    ret = mq_open(kMqName, openFlag, mode, attr);//posix
     if (ret == -1) {
         return (mqd_t)-get_errno();
     }
@@ -251,7 +270,7 @@ int SysSigTimedWait(const sigset_t_l *setl, siginfo_t *info, const struct timesp
     }
     return (ret == 0 ? infoIntr.si_signo : ret);
 }
-
+//IPC系统调用之暂停任务
 int SysPause(void)
 {
     return OsPause();

zzz/git/push.sh

 git add -A
-git commit -m  '如何跨CPU删除任务?注解一个任务是如何自杀和被他杀的.
+git commit -m  '1.注解系统调用是如何发生的 2.完善对消息队列的注解
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