注解汇编代码,原来它们竟如此可爱,爱了爱了.

    搜索 @note_pic 可查看绘制的全部字符图
    搜索 @note_why 是尚未看明白的地方，有看明白的，请Pull Request完善
    搜索 @note_thinking 是一些的思考和建议
    搜索 @note_#if0 是由第三方项目提供不在内核源码中定义的极为重要结构体，为方便理解而添加的。
    搜索 @note_good 是给源码点赞的地方

arch/arm/arm/include/arch_config.h

@@ -76,11 +76,18 @@ MRS{条件} 通用寄存器，程序状态寄存器(CPSR 或SPSR)
 	MRS R0，CPSR   @传送CPSR 的内容到R0
 	MRS R0，SPSR   @传送SPSR 的内容到R0
                	  @MRS指令是唯一可以直接读取CPSR和SPSR寄存器的指令
+
+SPSR
+	程序状态保护寄存器，每一种模式下都有一个状态寄存器SPSR，用于保存CPSR的状态，
+	以便异常返回后恢复异常发生时的工作状态。用户模式和系统模式不是异常状态，
+	所以没有SPSR，在这两种模式下访问SPSR，将产生不可预知的后果。
+	1、SPSR 为 CPSR 中断时刻的副本，退出中断后，将SPSR中数据恢复到CPSR中。
+	2、用户模式和系统模式下SPSR不可用。
 ******************************************************************************/
 #define CPSR_INT_DISABLE         0xC0 /* Disable both FIQ and IRQ */	//禁止IRQ和FIQ中断,因为0xC0 = 0x80 + 0x40
-#define CPSR_IRQ_DISABLE         0x80 /* IRQ disabled when =1 */		//只禁止IRQ 中断
+#define CPSR_IRQ_DISABLE         0x80 /* IRQ disabled when =1 */		//禁止IRQ 中断
 #define CPSR_FIQ_DISABLE         0x40 /* FIQ disabled when =1 */		//禁止 FIQ中断
-#define CPSR_THUMB_ENABLE        0x20 /* Thumb mode when   =1 */		//模式 1:CPU处于Thumb状态， 0:CPU处于ARM状态
+#define CPSR_THUMB_ENABLE        0x20 /* Thumb mode when   =1 */		//使能Thumb模式 1:CPU处于Thumb状态， 0:CPU处于ARM状态
 #define CPSR_USER_MODE           0x10	//用户模式,除了用户模式，其余模式也叫特权模式,特权模式中除了系统模式以外的其余5种模式称为异常模式；
 #define CPSR_FIQ_MODE            0x11	//快中断模式 用于高速数据传输或通道处理
 #define CPSR_IRQ_MODE            0x12	//中断模式 用于通用的中断处理

arch/arm/arm/src/los_dispatch.S

@@ -33,36 +33,36 @@
 #include "arch_config.h"
 
 #ifdef LOSCFG_KERNEL_SMP_LOCKDEP
-    .extern   OsLockDepCheckOut
+    .extern   OsLockDepCheckOut/*使用外部定义的函数*/
 #endif
     .extern   g_taskSpin
     .extern   g_percpu
-    .global   OsStartToRun
-    .global   OsTaskSchedule	/*任务调度*/
+    .global   OsStartToRun 		/*任务开始执行  告诉 OsStartToRun()在本文件实现,将被外部函数调用,见于OsStart()   */
+    .global   OsTaskSchedule	/*任务调度,见于OsSchedResched()*/
     .global   OsIrqHandler		/*硬中断处理*/
     .global   ArchSpinUnlock	/*自旋锁解锁*/
-    .global   OsSchedToUserSpinUnlock
+    .global   OsSchedToUserSpinUnlock /*尚未实现*/
 
-    .equ OS_TASK_STATUS_RUNNING,       0x0010U
+    .equ OS_TASK_STATUS_RUNNING,       0x0010U /* .equ用于把常量值设置为可以在文本段中使用的符号 #define OS_TASK_STATUS_RUNNING 0x0010U */
     .equ OS_PERCPU_STRUCT_SIZE,        0x28U
     .equ OS_PERCPU_TASK_LOCK_OFFSET,   0x14U
-    .fpu vfpv4
-
+    .fpu vfpv4 /* .fpu @note_why 尚未知这句话的含义 */
+/* 此宏用于对齐和不对齐8字节边界上的堆栈以符合ABI */
 /* macros to align and unalign the stack on 8 byte boundary for ABI compliance */
-.macro STACK_ALIGN, reg
+.macro STACK_ALIGN, reg /* 汇编带参数的宏定义*/ 
     MOV     \reg, sp
     TST     SP, #4
     SUBEQ   SP, #4
     PUSH    { \reg }
 .endm
 
-.macro STACK_RESTORE, reg
-    POP     { \reg }
+.macro STACK_RESTORE, reg /*汇编带参数的宏定义*/ 
+    POP     { \reg } @
     MOV     sp, \reg
 .endm
 
 /* macros to save and restore fpu regs */
-.macro PUSH_FPU_REGS reg1
+.macro PUSH_FPU_REGS reg1 /* 汇编宏定义,类似于 #define PUSH_FPU_REGS(reg1) ... */ 
 #if !defined(LOSCFG_ARCH_FPU_DISABLE)
     VMRS    \reg1, FPEXC
     PUSH    {\reg1}
@@ -106,7 +106,7 @@ OsStartToRun:
     VPUSH   {D0}
     VPOP    {D0}
 
-    B       OsTaskContextLoad
+    B       OsTaskContextLoad @加载任务的上下文
 
 /*
  * R0: new task
@@ -120,7 +120,7 @@ OsTaskSchedule:			/*新老任务切换上下文*/
     SUB      SP, SP, #4 /*SP=SP-4 减4是向低地址偏移4个字节的位置的地址，即堆栈的头部的地址*/
 
     /* push r0-r12*/
-    STMFD    SP!, {R0-R12} 	/*R0-R12入栈*/
+    STMFD    SP!, {R0-R12} 	 @将寄存器列表中的寄存器(R0-R12)压栈。
     STMFD    SP!, {R2}		/*R2 入栈*/
 
     /* 8 bytes stack align */
@@ -130,26 +130,26 @@ OsTaskSchedule:			/*新老任务切换上下文*/
     PUSH_FPU_REGS   R2	/*保存fpu寄存器*/
 
     /* store sp on running task */
-    STR     SP, [R1] /*在R1上保存了SP,保存了老任务的现场*/
+    STR     SP, [R1] @将sp中的数据保存到以R1为地址的存储器中
 
 OsTaskContextLoad:
-    /* clear the flag of ldrex */
-    CLREX
+    /* clear the flag of ldrex */ @LDREX 可从内存加载数据,如果物理地址有共享TLB属性，则LDREX会将该物理地址标记为由当前处理器独占访问，并且会清除该处理器对其他任何物理地址的任何独占访问标记。
+    CLREX @清除ldrex指令的标记
 
     /* switch to new task's sp */
-    LDR     SP, [R0]
+    LDR     SP, [R0] @将存储器地址为R0的数据读入寄存器SP
 
     /* restore fpu registers */
-    POP_FPU_REGS    R2
+    POP_FPU_REGS    R2 @恢复fpu寄存器,这里用了汇编宏R2是宏的参数
 
     /* 8 bytes stack align */
-    ADD     SP, SP, #4
+    ADD     SP, SP, #4 /*SP=SP+4*/
 
-    LDMFD   SP!, {R0}
-    MOV     R4, R0
-    AND     R0, R0, #CPSR_MASK_MODE
-    CMP     R0, #CPSR_USER_MODE
-    BNE     OsKernelTaskLoad
+    LDMFD   SP!, {R0}  @将堆栈内容出栈保存到寄存器R0
+    MOV     R4, R0	@R4=R0 说明R4也记录了CPSR内容,这个内容将用于 OsKernelTaskLoad中保存到SPSR 
+    AND     R0, R0, #CPSR_MASK_MODE @R0 =R0&CPSR_MASK_MODE ,目的是清除高16位
+    CMP     R0, #CPSR_USER_MODE @比较R0是否为用户模式
+    BNE     OsKernelTaskLoad @不相等则跳转到OsKernelTaskLoad执行
 
 #ifdef LOSCFG_KERNEL_SMP
 #ifdef LOSCFG_KERNEL_SMP_LOCKDEP
@@ -181,12 +181,12 @@ OsTaskContextLoad:
     ADD     SP, SP, #(2 * 4)
     LDMFD   SP!, {PC}^
 
-OsKernelTaskLoad:
-    MSR     SPSR_cxsf, R4
+OsKernelTaskLoad: @内核任务的加载
+    MSR     SPSR_cxsf, R4 @将R4保存到程序状态保存寄存器32位
     /* restore r0-r12, lr */
-    LDMFD   SP!, {R0-R12}
-    ADD     SP, SP, #4
-    LDMFD   SP!, {LR, PC}^
+    LDMFD   SP!, {R0-R12} @出栈,依次保存到 R0-R12,其实就是恢复现场
+    ADD     SP, SP, #4 @sp=SP+4
+    LDMFD   SP!, {LR, PC}^ @返回地址赋给pc指针
 
 OsIrqHandler:
     SUB     LR, LR, #4

arch/arm/arm/src/los_exc.c

@@ -84,6 +84,7 @@ extern "C" {
 	同时将函数入参、局部变量、寄存器入栈。栈帧从高地址向低地址生长。
 	
 	以ARM32 CPU架构为例，每个栈帧中都会保存PC、LR、SP和FP寄存器的历史值。
+	ARM处理器中的R13被用作SP
 
 堆栈分析
 	LR寄存器（Link Register），链接寄存器，指向函数的返回地址。
@@ -143,8 +144,8 @@ STATIC UINT32 g_nextExcWaitCpu = INVALID_CPUID;
 #define IS_VALID_ADDR(ptr) (((ptr) >= g_minAddr) &&       \
                             ((ptr) <= g_maxAddr) && \
                             (IS_ALIGNED((ptr), sizeof(CHAR *))))
-
-STATIC const StackInfo g_excStack[] = {// 6种异常情况下对应的栈 
+//6种异常情况下对应的栈,每一种异常模式都有其独立的堆栈,用不同的堆栈指针来索引,这样当ARM进入异常模式的时候，
+STATIC const StackInfo g_excStack[] = {//程序就可以把一般通用寄存器压入堆栈，返回时再出栈，保证了各种模式下程序的状态的完整性 
     { &__undef_stack, OS_EXC_UNDEF_STACK_SIZE, "udf_stack" },	//512 未定义的指令模式堆栈
     { &__abt_stack,   OS_EXC_ABT_STACK_SIZE,   "abt_stack" },	//512 中止模式堆栈,用于数据中止,可以将处理程序设置为在触发异常终止时运行
     { &__fiq_stack,   OS_EXC_FIQ_STACK_SIZE,   "fiq_stack" },	//64 FIQ中断模式堆栈.快速中断(FIQ)可能会在IRQ期间发生-它们就像优先级较高的IRQ.在FIQ中,FIQ和IRQ被禁用.

kernel/base/sched/sched_sq/los_sched.c

@@ -145,7 +145,7 @@ VOID OsSchedResched(VOID)
                 newProcess->threadScheduleMap, newTask->taskName, newTask->taskID, newTask->taskStatus);
 
     /* do the task context switch */
-    OsTaskSchedule(newTask, runTask);//切换CPU的上下文,由汇编实现,见于 los_dispatch.s
+    OsTaskSchedule(newTask, runTask);//切换CPU的上下文,注意OsTaskSchedule是一个汇编函数 见于 los_dispatch.s
 }
 
 VOID OsSchedPreempt(VOID)

kernel/common/los_config.c

@@ -165,7 +165,7 @@ LITE_OS_SEC_TEXT_INIT VOID OsStart(VOID)
     OS_SCHEDULER_SET(cpuid);//设置调度cpu id
 
     PRINTK("cpu %d entering scheduler\n", cpuid);
-    OsStartToRun(taskCB);//任务开始跑任务
+    OsStartToRun(taskCB);//任务开始跑,注意OsStartToRun是一个汇编函数 见于 los_dispatch.s
 }
 //进程通讯IPC初始化 由OsMain()调用
 LITE_OS_SEC_TEXT_INIT STATIC UINT32 OsIpcInit(VOID)

kernel/common/los_excinfo.c

-/*
- * 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.
- */
-
-#include "los_base.h"
-#include "los_hwi.h"
-#ifdef LOSCFG_FS_VFS
-#include "fs/fs.h"
-#endif
-
-#ifdef __cplusplus
-#if __cplusplus
-extern "C" {
-#endif /* __cplusplus */
-#endif /* __cplusplus */
-
-#ifdef LOSCFG_SHELL_EXCINFO
-STATIC log_read_write_fn g_excInfoRW = NULL; /* the hook of read-writing exception information *///读写异常信息的钩子
-STATIC CHAR *g_excInfoBuf = NULL;            /* pointer to the buffer for storing the exception information *///指向存储异常信息的缓冲区的指针
-STATIC UINT32 g_excInfoIndex = 0xFFFFFFFF;   /* the index of the buffer for storing the exception information *///用于存储异常信息的缓冲区的索引
-STATIC UINT32 g_recordAddr = 0;              /* the address of storing the exception information */ //存储异常信息的地址
-STATIC UINT32 g_recordSpace = 0;             /* the size of storing the exception information */	//存储异常信息的大小
-
-VOID SetExcInfoRW(log_read_write_fn func)
-{
-    g_excInfoRW = func;
-}
-
-log_read_write_fn GetExcInfoRW(VOID)
-{
-    return g_excInfoRW;
-}
-
-VOID SetExcInfoBuf(CHAR *buf)
-{
-    g_excInfoBuf = buf;
-}
-
-CHAR *GetExcInfoBuf(VOID)
-{
-    return g_excInfoBuf;
-}
-
-VOID SetExcInfoIndex(UINT32 index)
-{
-    g_excInfoIndex = index;
-}
-
-UINT32 GetExcInfoIndex(VOID)
-{
-    return g_excInfoIndex;
-}
-
-VOID SetRecordAddr(UINT32 addr)
-{
-    g_recordAddr = addr;
-}
-
-UINT32 GetRecordAddr(VOID)
-{
-    return g_recordAddr;
-}
-
-VOID SetRecordSpace(UINT32 space)
-{
-    g_recordSpace = space;
-}
-
-UINT32 GetRecordSpace(VOID)
-{
-    return g_recordSpace;
-}
-//vsnprintf 为C标准库可变参数的实现函数 见于 ..\third_party\musl\kernel\src\stdio\vsnprintf.c
-VOID WriteExcBufVa(const CHAR *format, va_list arglist)
-{
-    errno_t ret;
-
-    if (g_recordSpace > g_excInfoIndex) {
-        ret = vsnprintf_s((g_excInfoBuf + g_excInfoIndex), (g_recordSpace - g_excInfoIndex),
-                          (g_recordSpace - g_excInfoIndex - 1), format, arglist);
-        if (ret == -1) {
-            PRINT_ERR("exc info buffer is not enough or vsnprintf_s is error.\n");
-            return;
-        }
-        g_excInfoIndex += ret;
-    }
-}
-//写异常信息到系统异常信息中心
-VOID WriteExcInfoToBuf(const CHAR *format, ...)
-{
-    va_list arglist;//va_arg
-    va_start(arglist, format);//从任务栈中取出入栈参数
-    WriteExcBufVa(format, arglist);//入栈参数列表作为实参传入交由vsnprintf处理
-    va_end(arglist);//释放资源
-}
-//用于注册记录异常信息函数，并指定位置、空间和大小
-VOID LOS_ExcInfoRegHook(UINT32 startAddr, UINT32 space, CHAR *buf, log_read_write_fn hook)
-{
-    if ((hook == NULL) || (buf == NULL)) {
-        PRINT_ERR("Buf or hook is null.\n");
-        return;
-    }
-
-    g_recordAddr = startAddr;
-    g_recordSpace = space;
-    g_excInfoBuf = buf;
-    g_excInfoRW = hook;
-
-#ifdef LOSCFG_FS_VFS
-    los_vfs_init();//初始化虚拟文件系统
-#endif
-}
-
-/* Be called in the exception. */
-VOID OsReadWriteExceptionInfo(UINT32 startAddr, UINT32 space, UINT32 flag, CHAR *buf)
-{
-    if ((buf == NULL) || (space == 0)) {
-        PRINT_ERR("buffer is null or space is zero\n");
-        return;
-    }
-    // user can write exception information to files here
-}
-//记录异常信息发送的时间
-VOID OsRecordExcInfoTime(VOID)
-{
-#ifdef LOSCFG_FS_VFS
-#define NOW_TIME_LENGTH 24
-    time_t t;
-    struct tm *tmTime = NULL;
-    CHAR nowTime[NOW_TIME_LENGTH];
-
-    (VOID)time(&t);
-    tmTime = localtime(&t);//获取本地时间的标准C库函数
-    if (tmTime == NULL) {
-        return;
-    }
-    (VOID)memset_s(nowTime, sizeof(nowTime), 0, sizeof(nowTime));
-    (VOID)strftime(nowTime, NOW_TIME_LENGTH, "%Y-%m-%d %H:%M:%S", tmTime);//生成时间格式
-#undef NOW_TIME_LENGTH
-    WriteExcInfoToBuf("%s \n", nowTime);
-#endif
-}
-
-#endif
-
-#ifdef __cplusplus
-#if __cplusplus
-}
-#endif /* __cplusplus */
-#endif /* __cplusplus */
+/*
+ * 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.
+ */
+
+#include "los_base.h"
+#include "los_hwi.h"
+#ifdef LOSCFG_FS_VFS
+#include "fs/fs.h"
+#endif
+
+#ifdef __cplusplus
+#if __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+#endif /* __cplusplus */
+
+#ifdef LOSCFG_SHELL_EXCINFO //异常信息开关
+STATIC log_read_write_fn g_excInfoRW = NULL; /* the hook of read-writing exception information */	//读写异常信息的钩子函数
+STATIC CHAR *g_excInfoBuf = NULL;            /* pointer to the buffer for storing the exception information */	//指向存储异常信息的缓冲区的指针
+STATIC UINT32 g_excInfoIndex = 0xFFFFFFFF;   /* the index of the buffer for storing the exception information */	//用于存储异常信息的缓冲区的索引
+STATIC UINT32 g_recordAddr = 0;              /* the address of storing the exception information */ //存储异常信息的地址
+STATIC UINT32 g_recordSpace = 0;             /* the size of storing the exception information */	//存储异常信息的大小
+//设置异常信息的读写函数
+VOID SetExcInfoRW(log_read_write_fn func)
+{
+    g_excInfoRW = func;
+}
+//获取异常信息读写函数
+log_read_write_fn GetExcInfoRW(VOID)
+{
+    return g_excInfoRW;
+}
+//设置异常信息的缓存
+VOID SetExcInfoBuf(CHAR *buf)
+{
+    g_excInfoBuf = buf;
+}
+//获取异常信息的缓存
+CHAR *GetExcInfoBuf(VOID)
+{
+    return g_excInfoBuf;
+}
+//设置异常信息索引位
+VOID SetExcInfoIndex(UINT32 index)
+{
+    g_excInfoIndex = index;
+}
+//获取异常信息索引位
+UINT32 GetExcInfoIndex(VOID)
+{
+    return g_excInfoIndex;
+}
+
+VOID SetRecordAddr(UINT32 addr)
+{
+    g_recordAddr = addr;
+}
+
+UINT32 GetRecordAddr(VOID)
+{
+    return g_recordAddr;
+}
+
+VOID SetRecordSpace(UINT32 space)
+{
+    g_recordSpace = space;
+}
+
+UINT32 GetRecordSpace(VOID)
+{
+    return g_recordSpace;
+}
+//vsnprintf 为C标准库可变参数的实现函数 见于 ..\third_party\musl\kernel\src\stdio\vsnprintf.c
+VOID WriteExcBufVa(const CHAR *format, va_list arglist)
+{
+    errno_t ret;
+
+    if (g_recordSpace > g_excInfoIndex) {
+        ret = vsnprintf_s((g_excInfoBuf + g_excInfoIndex), (g_recordSpace - g_excInfoIndex),
+                          (g_recordSpace - g_excInfoIndex - 1), format, arglist);
+        if (ret == -1) {
+            PRINT_ERR("exc info buffer is not enough or vsnprintf_s is error.\n");
+            return;
+        }
+        g_excInfoIndex += ret;
+    }
+}
+//写异常信息到系统异常信息中心
+VOID WriteExcInfoToBuf(const CHAR *format, ...)
+{
+    va_list arglist;//va_arg
+    va_start(arglist, format);//从任务栈中取出入栈参数
+    WriteExcBufVa(format, arglist);//入栈参数列表作为实参传入交由vsnprintf处理
+    va_end(arglist);//释放资源
+}
+//用于注册记录异常信息函数，并指定位置、空间和大小
+VOID LOS_ExcInfoRegHook(UINT32 startAddr, UINT32 space, CHAR *buf, log_read_write_fn hook)
+{
+    if ((hook == NULL) || (buf == NULL)) {
+        PRINT_ERR("Buf or hook is null.\n");
+        return;
+    }
+
+    g_recordAddr = startAddr;
+    g_recordSpace = space;
+    g_excInfoBuf = buf;
+    g_excInfoRW = hook;
+
+#ifdef LOSCFG_FS_VFS
+    los_vfs_init();//初始化虚拟文件系统
+#endif
+}
+
+/* Be called in the exception. */ //异常发生时回调这里
+VOID OsReadWriteExceptionInfo(UINT32 startAddr, UINT32 space, UINT32 flag, CHAR *buf)
+{
+    if ((buf == NULL) || (space == 0)) {
+        PRINT_ERR("buffer is null or space is zero\n");
+        return;
+    }
+    // user can write exception information to files here
+}
+//记录异常信息产生的时间
+VOID OsRecordExcInfoTime(VOID)
+{
+#ifdef LOSCFG_FS_VFS
+#define NOW_TIME_LENGTH 24
+    time_t t;
+    struct tm *tmTime = NULL;
+    CHAR nowTime[NOW_TIME_LENGTH];
+
+    (VOID)time(&t);
+    tmTime = localtime(&t);//获取本地时间的标准C库函数
+    if (tmTime == NULL) {
+        return;
+    }
+    (VOID)memset_s(nowTime, sizeof(nowTime), 0, sizeof(nowTime));
+    (VOID)strftime(nowTime, NOW_TIME_LENGTH, "%Y-%m-%d %H:%M:%S", tmTime);//生成时间格式
+#undef NOW_TIME_LENGTH
+    WriteExcInfoToBuf("%s \n", nowTime);
+#endif
+}
+
+#endif
+
+#ifdef __cplusplus
+#if __cplusplus
+}
+#endif /* __cplusplus */
+#endif /* __cplusplus */

kernel/include/los_spinlock.h

@@ -203,7 +203,7 @@ LITE_OS_SEC_ALW_INLINE STATIC INLINE INT32 LOS_SpinTrylock(SPIN_LOCK_S *lock)
 LITE_OS_SEC_ALW_INLINE STATIC INLINE VOID LOS_SpinUnlock(SPIN_LOCK_S *lock)
 {
     LOCKDEP_CHECK_OUT(lock);
-    ArchSpinUnlock(&lock->rawLock);
+    ArchSpinUnlock(&lock->rawLock);//注意ArchSpinUnlock是一个汇编函数 见于 los_dispatch.s
 
     /* restore the scheduler flag */
     LOS_TaskUnlock();

zzz/git/push.sh

 git add -A
-git commit -m  '注解:CPSR(当前程序的状态寄存器)各位表示什么含义 ? 如何读取这个寄存器 ?
+git commit -m  '注解汇编代码,原来它们竟如此可爱,爱了爱了.
     搜索 @note_pic 可查看绘制的全部字符图
     搜索 @note_why 是尚未看明白的地方，有看明白的，请Pull Request完善
     搜索 @note_thinking 是一些的思考和建议