鸿蒙源码分析系列篇 https://blog.csdn.net/kuangyufei

                https://my.oschina.net/u/3751245

arch/arm/arm/include/arch_config.h

@@ -64,9 +64,9 @@
 #endif
 
 /* Initial bit32 stack value. */
-#define OS_STACK_INIT            0xCACACACA
+#define OS_STACK_INIT            0xCACACACA	//栈指针初始化值 0b 1010 1010 1010
 /* Bit32 stack top magic number. */
-#define OS_STACK_MAGIC_WORD      0xCCCCCCCC
+#define OS_STACK_MAGIC_WORD      0xCCCCCCCC //用于栈顶值,可标识为栈是否被使用过,神奇的 "烫烫烫烫"的根源所在! 0b 1100 1100 1100
 
 #ifdef LOSCFG_GDB
 #define OS_EXC_UNDEF_STACK_SIZE  512

arch/arm/arm/include/los_hw_cpu.h

@@ -87,7 +87,7 @@ extern "C" {
  * Identification registers (c0)
  */
 #define MIDR                CP15_REG(c0, 0, c0, 0)    /* Main ID Register */
-#define MPIDR               CP15_REG(c0, 0, c0, 5)    /* Multiprocessor Affinity Register */
+#define MPIDR               CP15_REG(c0, 0, c0, 5)    /* Multiprocessor Affinity Register *///多处理器关联寄存器给每个CPU制定一个逻辑地址
 #define CCSIDR              CP15_REG(c0, 1, c0, 0)    /* Cache Size ID Registers */
 #define CLIDR               CP15_REG(c0, 1, c0, 1)    /* Cache Level ID Register */
 #define VPIDR               CP15_REG(c0, 4, c0, 0)    /* Virtualization Processor ID Register */
@@ -141,12 +141,12 @@ STATIC INLINE VOID ArchCurrUserTaskSet(UINTPTR val)
 {
     ARM_SYSREG_WRITE(TPIDRURO, (UINT32)val);
 }
-
+//https://www.keil.com/pack/doc/cmsis/Core_A/html/group__CMSIS__MPIDR.html
 STATIC INLINE UINT32 ArchCurrCpuid(VOID)
 {
-#if (LOSCFG_KERNEL_SMP == YES)
+#if (LOSCFG_KERNEL_SMP == YES)//CPU多核情况
     return ARM_SYSREG_READ(MPIDR) & MPIDR_CPUID_MASK;
-#else
+#else//ARM架构通过MPIDR(Multiprocessor Affinity Register)寄存器给每个CPU制定一个逻辑地址。
     return 0;
 #endif
 }

arch/arm/arm/src/los_hw.c

@@ -39,7 +39,7 @@ extern "C" {
 #endif /* __cplusplus */
 
 /* support cpu vendors */
-CpuVendor g_cpuTable[] = {
+CpuVendor g_cpuTable[] = {//支持的CPU供应商
     /* armv7-a */
     { 0xc07, "Cortex-A7" },
     { 0xc09, "Cortex-A9" },

kernel/base/core/los_process.c

@@ -607,21 +607,21 @@ LITE_OS_SEC_TEXT VOID OsProcessCBRecyleToFree(VOID)
 
     SCHEDULER_UNLOCK(intSave);
 }
-
+//获取一个可用的PCB(进程控制块)
 STATIC LosProcessCB *OsGetFreePCB(VOID)
 {
     LosProcessCB *processCB = NULL;
     UINT32 intSave;
 
     SCHEDULER_LOCK(intSave);
-    if (LOS_ListEmpty(&g_freeProcess)) {
+    if (LOS_ListEmpty(&g_freeProcess)) {//空闲池里还有未分配的task?
         SCHEDULER_UNLOCK(intSave);
         PRINT_ERR("No idle PCB in the system!\n");
         return NULL;
     }
 
-    processCB = OS_PCB_FROM_PENDLIST(LOS_DL_LIST_FIRST(&g_freeProcess));
-    LOS_ListDelete(&processCB->pendList);
+    processCB = OS_PCB_FROM_PENDLIST(LOS_DL_LIST_FIRST(&g_freeProcess));//拿到PCB,通过OS_PCB_FROM_PENDLIST是因为通过pendlist 节点挂在 freelist链表上.
+    LOS_ListDelete(&processCB->pendList);//分配出来了就要在freelist将自己摘除
     SCHEDULER_UNLOCK(intSave);
 
     return processCB;
@@ -1336,16 +1336,16 @@ ERROR:
     SCHEDULER_UNLOCK(intSave);
     return pid;
 }
-
+//设置进程组检查
 STATIC UINT32 OsSetProcessGroupCheck(const LosProcessCB *processCB, UINT32 gid)
 {
-    LosProcessCB *runProcessCB = OsCurrProcessGet();
-    LosProcessCB *groupProcessCB = OS_PCB_FROM_PID(gid);
+    LosProcessCB *runProcessCB = OsCurrProcessGet();//拿到当前运行进程
+    LosProcessCB *groupProcessCB = OS_PCB_FROM_PID(gid);//通过组ID拿到组长PCB实体
 
-    if (OsProcessIsInactive(processCB)) {
+    if (OsProcessIsInactive(processCB)) {//进程是否活动
         return LOS_ESRCH;
     }
-
+	//参数进程不在用户态或者组长不在用户态
     if (!OsProcessIsUserMode(processCB) || !OsProcessIsUserMode(groupProcessCB)) {
         return LOS_EPERM;
     }

kernel/base/core/los_task.c

@@ -335,8 +335,8 @@ LITE_OS_SEC_TEXT_INIT UINT32 OsTaskInit(VOID)
     for (index = 0; index < g_taskMaxNum; index++) {
         g_taskCBArray[index].taskStatus = OS_TASK_STATUS_UNUSED;
         g_taskCBArray[index].taskID = index;//任务ID最大默认127
-        LOS_ListTailInsert(&g_losFreeTask, &g_taskCBArray[index].pendList);//都插入空闲任务列表
-    }
+        LOS_ListTailInsert(&g_losFreeTask, &g_taskCBArray[index].pendList);//都插入空闲任务列表 
+    }//注意:这里挂的是pendList节点,所以取TCB要通过 OS_TCB_FROM_PENDLIST 取.
 
     ret = OsPriQueueInit();//创建32个任务优先级队列，即32个双向循环链表
     if (ret != LOS_OK) {
@@ -352,32 +352,32 @@ LITE_OS_SEC_TEXT_INIT UINT32 OsTaskInit(VOID)
     }
     return LOS_OK;
 }
-
+//获取IdletaskId,每个CPU核都对Task进行了内部管理,做到真正的并行处理
 UINT32 OsGetIdleTaskId(VOID)
 {
-    Percpu *perCpu = OsPercpuGet();
-    return perCpu->idleTaskID;
+    Percpu *perCpu = OsPercpuGet();//获取当前Cpu信息
+    return perCpu->idleTaskID;//返回当前CPU 空闲任务ID
 }
-
+//创建一个空闲任务
 LITE_OS_SEC_TEXT_INIT UINT32 OsIdleTaskCreate(VOID)
 {
     UINT32 ret;
     TSK_INIT_PARAM_S taskInitParam;
-    Percpu *perCpu = OsPercpuGet();
+    Percpu *perCpu = OsPercpuGet();//获取CPU信息
     UINT32 *idleTaskID = &perCpu->idleTaskID;
 
-    (VOID)memset_s((VOID *)(&taskInitParam), sizeof(TSK_INIT_PARAM_S), 0, sizeof(TSK_INIT_PARAM_S));
-    taskInitParam.pfnTaskEntry = (TSK_ENTRY_FUNC)OsIdleTask;
-    taskInitParam.uwStackSize = LOSCFG_BASE_CORE_TSK_IDLE_STACK_SIZE;
-    taskInitParam.pcName = "Idle";
-    taskInitParam.usTaskPrio = OS_TASK_PRIORITY_LOWEST;
-    taskInitParam.uwResved = OS_TASK_FLAG_IDLEFLAG;
-#if (LOSCFG_KERNEL_SMP == YES)
-    taskInitParam.usCpuAffiMask = CPUID_TO_AFFI_MASK(ArchCurrCpuid());
+    (VOID)memset_s((VOID *)(&taskInitParam), sizeof(TSK_INIT_PARAM_S), 0, sizeof(TSK_INIT_PARAM_S));//任务初始参数清0
+    taskInitParam.pfnTaskEntry = (TSK_ENTRY_FUNC)OsIdleTask;//入口函数指定idle
+    taskInitParam.uwStackSize = LOSCFG_BASE_CORE_TSK_IDLE_STACK_SIZE;//任务栈大小
+    taskInitParam.pcName = "Idle";//任务名称 叫pcName有点怪怪的,不能换个撒
+    taskInitParam.usTaskPrio = OS_TASK_PRIORITY_LOWEST;//默认最低优先级 31
+    taskInitParam.uwResved = OS_TASK_FLAG_IDLEFLAG;//默认idle flag
+#if (LOSCFG_KERNEL_SMP == YES)//CPU多核情况
+    taskInitParam.usCpuAffiMask = CPUID_TO_AFFI_MASK(ArchCurrCpuid());//意思是归于哪个CPU核调度,
 #endif
-    ret = LOS_TaskCreate(idleTaskID, &taskInitParam);
-    OS_TCB_FROM_TID(*idleTaskID)->taskStatus |= OS_TASK_FLAG_SYSTEM_TASK;
-
+    ret = LOS_TaskCreate(idleTaskID, &taskInitParam);//创建task并申请调度,
+    OS_TCB_FROM_TID(*idleTaskID)->taskStatus |= OS_TASK_FLAG_SYSTEM_TASK;//设置task状态为系统任务,系统任务运行在内核态.
+	//这里说下系统任务有哪些?比如: idle,swtmr(软时钟)等等 
     return ret;
 }
 
@@ -398,7 +398,7 @@ LITE_OS_SEC_TEXT UINT32 LOS_CurTaskIDGet(VOID)
 #if (LOSCFG_BASE_CORE_TSK_MONITOR == YES)
 LITE_OS_SEC_TEXT STATIC VOID OsTaskStackCheck(LosTaskCB *oldTask, LosTaskCB *newTask)
 {
-    if (!OS_STACK_MAGIC_CHECK(oldTask->topOfStack)) {
+    if (!OS_STACK_MAGIC_CHECK(oldTask->topOfStack)) {//magic检查无效情况
         LOS_Panic("CURRENT task ID: %s:%d stack overflow!\n", oldTask->taskName, oldTask->taskID);
     }
 
@@ -414,20 +414,20 @@ LITE_OS_SEC_TEXT STATIC VOID OsTaskStackCheck(LosTaskCB *oldTask, LosTaskCB *new
 }
 
 #endif
-
+//任务切换检查
 LITE_OS_SEC_TEXT_MINOR UINT32 OsTaskSwitchCheck(LosTaskCB *oldTask, LosTaskCB *newTask)
 {
-#if (LOSCFG_BASE_CORE_TSK_MONITOR == YES)
-    OsTaskStackCheck(oldTask, newTask);
+#if (LOSCFG_BASE_CORE_TSK_MONITOR == YES)//这里宏指任务栈有没有启动监控
+    OsTaskStackCheck(oldTask, newTask);//任务栈监控检查
 #endif /* LOSCFG_BASE_CORE_TSK_MONITOR == YES */
 
 #if (LOSCFG_KERNEL_TRACE == YES)
-    LOS_Trace(LOS_TRACE_SWITCH, newTask->taskID, oldTask->taskID);
+    LOS_Trace(LOS_TRACE_SWITCH, newTask->taskID, oldTask->taskID);//打印新老任务
 #endif
 
     return LOS_OK;
 }
-
+//任务退出
 LITE_OS_SEC_TEXT VOID OsTaskToExit(LosTaskCB *taskCB, UINT32 status)
 {
     UINT32 intSave;
@@ -478,10 +478,10 @@ LITE_OS_SEC_TEXT_INIT VOID OsTaskEntry(UINT32 taskID)
     (VOID)LOS_IntUnLock();
 
     taskCB = OS_TCB_FROM_TID(taskID);
-    taskCB->joinRetval = taskCB->taskEntry(taskCB->args[0], taskCB->args[1],
+    taskCB->joinRetval = taskCB->taskEntry(taskCB->args[0], taskCB->args[1],//调用入口函数
                                            taskCB->args[2], taskCB->args[3]); /* 2 & 3: just for args array index */
-    if (taskCB->taskStatus & OS_TASK_FLAG_DETACHED) {
-        taskCB->joinRetval = 0;
+    if (taskCB->taskStatus & OS_TASK_FLAG_DETACHED) {//task有分离标签时
+        taskCB->joinRetval = 0;//结合数为0
     }
 
     OsTaskToExit(taskCB, 0);
@@ -766,21 +766,21 @@ LITE_OS_SEC_TEXT_INIT STATIC UINT32 OsTaskCBInit(LosTaskCB *taskCB, const TSK_IN
 
     return LOS_OK;
 }
-
+//获取一个空闲TCB
 LITE_OS_SEC_TEXT LosTaskCB *OsGetFreeTaskCB(VOID)
 {
     UINT32 intSave;
     LosTaskCB *taskCB = NULL;
 
     SCHEDULER_LOCK(intSave);
-    if (LOS_ListEmpty(&g_losFreeTask)) {
+    if (LOS_ListEmpty(&g_losFreeTask)) {//全局空闲task为空
         SCHEDULER_UNLOCK(intSave);
         PRINT_ERR("No idle TCB in the system!\n");
         return NULL;
     }
 
-    taskCB = OS_TCB_FROM_PENDLIST(LOS_DL_LIST_FIRST(&g_losFreeTask));
-    LOS_ListDelete(LOS_DL_LIST_FIRST(&g_losFreeTask));
+    taskCB = OS_TCB_FROM_PENDLIST(LOS_DL_LIST_FIRST(&g_losFreeTask));//拿到第一节点并通过pendlist拿到完整的TCB
+    LOS_ListDelete(LOS_DL_LIST_FIRST(&g_losFreeTask));//从g_losFreeTask链表中摘除自己
     SCHEDULER_UNLOCK(intSave);
 
     return taskCB;

kernel/base/include/los_percpu_pri.h

@@ -66,7 +66,7 @@ typedef struct {
 } Percpu;
 
 /* the kernel per-cpu structure */
-extern Percpu g_percpu[LOSCFG_KERNEL_CORE_NUM];
+extern Percpu g_percpu[LOSCFG_KERNEL_CORE_NUM];//CPU核
 
 STATIC INLINE Percpu *OsPercpuGet(VOID)
 {

kernel/base/include/los_process_pri.h

@@ -239,7 +239,7 @@ typedef struct ProcessCB {
  * The process is dying or already dying.
  */
 #define OS_PROCESS_STATUS_INACTIVE       (OS_PROCESS_FLAG_EXIT | OS_PROCESS_STATUS_ZOMBIES) 
-//不活跃进程定义: 身上贴有退出便签且状态为僵死的进程
+//进程不活跃状态定义: 身上贴有退出便签且状态为僵死的进程
 /**
  * @ingroup los_process
  * Used to check if the process control block is unused.
@@ -256,7 +256,7 @@ STATIC INLINE BOOL OsProcessIsUnused(const LosProcessCB *processCB)//查下进
 STATIC INLINE BOOL OsProcessIsInactive(const LosProcessCB *processCB)//查下进程是否不活跃?
 {
     return ((processCB->processStatus & (OS_PROCESS_FLAG_UNUSED | OS_PROCESS_STATUS_INACTIVE)) != 0);
-}
+}//进程不活跃函数定义:身上贴有不使用且不活跃标签的进程
 
 /**
  * @ingroup los_process

kernel/base/include/los_task_pri.h

@@ -177,16 +177,16 @@ extern SPIN_LOCK_S g_taskSpin;
  *
  * The task is joinable.
  */
-#define OS_TASK_FLAG_PTHREAD_JOIN   0x0400U
-
+#define OS_TASK_FLAG_PTHREAD_JOIN   0x0400U //主task和子task连在一块不分离
+//一个可结合的线程能够被其他线程收回其资源和杀死。在被其他线程回收之前，它的存储器资源（例如栈）是不释放的。
 /**
  * @ingroup los_task
  * Flag that indicates the task or task control block status.
  *
  * The task is status detached.
  */
-#define OS_TASK_FLAG_DETACHED       0x0800U
-
+#define OS_TASK_FLAG_DETACHED       0x0800U //任务分离 主task与子task分离，子task结束后，资源自动回收
+//一个分离的线程是不能被其他线程回收或杀死的，它的存储器资源在它终止时由系统自动释放。
 /**
  * @ingroup los_task
  * Flag that indicates the task property.
@@ -264,7 +264,7 @@ extern SPIN_LOCK_S g_taskSpin;
 * @see
 */
 #define OS_TCB_FROM_PENDLIST(ptr) LOS_DL_LIST_ENTRY(ptr, LosTaskCB, pendList)
-
+//通过pendList取出TCB,用于挂入链表节点时使用 pendList的情况 
 /**
 * @ingroup  los_task
 * @brief Obtain the pointer to a task control block.
@@ -281,7 +281,7 @@ extern SPIN_LOCK_S g_taskSpin;
 * @see
 */
 #define OS_TCB_FROM_TID(taskID) (((LosTaskCB *)g_taskCBArray) + (taskID))
-
+//通过Tid找到TCB
 #ifndef LOSCFG_STACK_POINT_ALIGN_SIZE
 #define LOSCFG_STACK_POINT_ALIGN_SIZE                       (sizeof(UINTPTR) * 2)
 #endif

kernel/base/misc/los_stackinfo.c

@@ -112,7 +112,7 @@ VOID OsExcStackInfoReg(const StackInfo *stackInfo, UINT32 stackNum)
     g_stackInfo = stackInfo;
     g_stackNum = stackNum;
 }
-
+//栈的初始化,设置固定的值. 0xcccccccc 和 0xcacacaca
 VOID OsStackInit(VOID *stacktop, UINT32 stacksize)
 {
     /* initialize the task stack, write magic num to stack top */

kernel/common/los_config.h

@@ -222,7 +222,7 @@ extern UINT32 __heap_end;		// 堆区结束地址
  * @ingroup los_config
  * Configuration item for task (stack) monitoring module tailoring
  */
-#ifndef LOSCFG_BASE_CORE_TSK_MONITOR
+#ifndef LOSCFG_BASE_CORE_TSK_MONITOR //任务（栈）监控模块裁剪配置项
 #define LOSCFG_BASE_CORE_TSK_MONITOR YES
 #endif