对 vdso 实现注解

    百万汉字注解 + 百篇博客分析 => 挖透鸿蒙内核源码
    国内:https://weharmony.21cloudbox.com
    国外:https://weharmony.github.io

bsd/dev/usb/usb_debug.c

-../../../../../third_party/FreeBSD/sys/dev/usb/usb_debug.c
+../../../../../third_party/FreeBSD/sys/dev/usb/usb_debug.c
\ No newline at end of file

bsd/dev/usb/usb_dev.c

-../../../../../third_party/FreeBSD/sys/dev/usb/usb_dev.c
+../../../../../third_party/FreeBSD/sys/dev/usb/usb_dev.c
\ No newline at end of file

bsd/dev/usb/usb_device.c

-../../../../../third_party/FreeBSD/sys/dev/usb/usb_device.c
+../../../../../third_party/FreeBSD/sys/dev/usb/usb_device.c
\ No newline at end of file

compat/posix/src/time.c

@@ -133,11 +133,11 @@ STATIC const long long g_adjPacement = (((LOSCFG_BASE_CORE_ADJ_PER_SECOND * SCHE
                                         LOSCFG_BASE_CORE_TICK_PER_SECOND) * OS_SYS_NS_PER_US);
 
 /* accumulative time delta from continuous modify, such as adjtime */
-STATIC struct timespec64 g_accDeltaFromAdj;
+STATIC struct timespec64 g_accDeltaFromAdj;//连续修改的累积时间增量，例如 adjtime
 /* accumulative time delta from discontinuous modify, such as settimeofday */
-STATIC struct timespec64 g_accDeltaFromSet;
+STATIC struct timespec64 g_accDeltaFromSet;//来自不连续修改的累积时间增量，例如 settimeofday
 
-VOID OsAdjTime(VOID)
+VOID OsAdjTime(VOID)//时间调整
 {
     UINT32 intSave;
 
@@ -272,12 +272,12 @@ STATIC INLINE struct timespec64 OsTimeSpecSub(const struct timespec64 t1, const
 
     return ret;
 }
-
+//获取硬件时间
 STATIC VOID OsGetHwTime(struct timespec64 *hwTime)
 {
     UINT64 nowNsec;
 
-    nowNsec = LOS_CurrNanosec();
+    nowNsec = LOS_CurrNanosec();//当前纳秒
     hwTime->tv_sec = nowNsec / OS_SYS_NS_PER_SECOND;
     hwTime->tv_nsec = nowNsec - hwTime->tv_sec * OS_SYS_NS_PER_SECOND;
 }
@@ -1096,7 +1096,7 @@ int getitimer(int which, struct itimerval *value)
 }
 
 #ifdef LOSCFG_KERNEL_VDSO
-VOID OsVdsoTimeGet(VdsoDataPage *vdsoDataPage)
+VOID OsVdsoTimeGet(VdsoDataPage *vdsoDataPage)//获取数据页信息
 {
     UINT32 intSave;
     struct timespec64 tmp = {0};
@@ -1109,11 +1109,11 @@ VOID OsVdsoTimeGet(VdsoDataPage *vdsoDataPage)
     OsGetHwTime(&hwTime);
 
     LOS_SpinLockSave(&g_timeSpin, &intSave);
-    tmp = OsTimeSpecAdd(hwTime, g_accDeltaFromAdj);
+    tmp = OsTimeSpecAdd(hwTime, g_accDeltaFromAdj);//添加时间
     vdsoDataPage->monoTimeSec = tmp.tv_sec;
     vdsoDataPage->monoTimeNsec = tmp.tv_nsec;
 
-    tmp = OsTimeSpecAdd(tmp, g_accDeltaFromSet);
+    tmp = OsTimeSpecAdd(tmp, g_accDeltaFromSet);//添加时间
     vdsoDataPage->realTimeSec = tmp.tv_sec;
     vdsoDataPage->realTimeNsec = tmp.tv_nsec;
     LOS_SpinUnlockRestore(&g_timeSpin, intSave);

fs/include/fs/mount.h

@@ -52,7 +52,7 @@ struct Mount {//装载
     int vnodeSize;                     /* size of vnode list */	//节点数量
     LIST_HEAD activeVnodeList;         /* list of active vnodes */	//激活的节点链表
     int activeVnodeSize;               /* szie of active vnodes list *///激活的节点数量
-    void *data;                        /* private data */	//私有数据
+    void *data;                        /* private data */	//私有数据,可使用这个成员作为一个指向它们自己内部数据的指针
     uint32_t hashseed;                 /* Random seed for vfs hash */ //vfs 哈希随机种子
     unsigned long mountFlags;          /* Flags for mount */	//装载标签
     char pathName[PATH_MAX];           /* path name of mount point */	//装载点路径名称

fs/vfs/operation/fs_init.c

@@ -105,4 +105,4 @@ void los_vfs_init(void)//只能调用一次，多次调用将会造成文件系
     g_vfs_init = true;
 }
 
-LOS_MODULE_INIT(los_vfs_init, LOS_INIT_LEVEL_KMOD_BASIC);
+LOS_MODULE_INIT(los_vfs_init, LOS_INIT_LEVEL_KMOD_BASIC);//文件模块初始化

kernel/base/core/los_task.c

@@ -1776,4 +1776,4 @@ LITE_OS_SEC_TEXT UINT32 OsResourceFreeTaskCreate(VOID)
     return ret;
 }
 
-LOS_MODULE_INIT(OsResourceFreeTaskCreate, LOS_INIT_LEVEL_KMOD_TASK);
+LOS_MODULE_INIT(OsResourceFreeTaskCreate, LOS_INIT_LEVEL_KMOD_TASK);//资源回收任务初始化

kernel/base/mp/los_mp.c

@@ -123,7 +123,7 @@ UINT32 OsMpInit(VOID)
     return LOS_OK;
 }
 
-LOS_MODULE_INIT(OsMpInit, LOS_INIT_LEVEL_KMOD_TASK);
+LOS_MODULE_INIT(OsMpInit, LOS_INIT_LEVEL_KMOD_TASK);//多处理器模块初始化
 
 #endif
 

kernel/base/sched/sched_sq/los_sched.c

@@ -812,7 +812,7 @@ UINT32 OsSchedInit(VOID)
 #endif
     return LOS_OK;
 }
-
+//获取优先级最高的任务
 STATIC LosTaskCB *OsGetTopTask(VOID)
 {
     UINT32 priority, processPriority;
@@ -849,7 +849,7 @@ FIND_TASK:
     OsSchedDeTaskQueue(newTask, OS_PCB_FROM_PID(newTask->processID));
     return newTask;
 }
-
+//开始调度,每个CPU核都会执行这个函数一次.
 VOID OsSchedStart(VOID)
 {
     UINT32 cpuid = ArchCurrCpuid();

kernel/base/vm/los_vm_dump.c

@@ -80,7 +80,7 @@ const CHAR *OsGetRegionNameOrFilePath(LosVmMapRegion *region)
     }
     return "";
 }
-
+//
 INT32 OsRegionOverlapCheckUnlock(LosVmSpace *space, LosVmMapRegion *region)
 {
     LosVmMapRegion *regionTemp = NULL;

kernel/base/vm/oom.c

@@ -247,7 +247,7 @@ LITE_OS_SEC_TEXT_MINOR UINT32 OomTaskInit(VOID)
 #endif
 }
 
-LOS_MODULE_INIT(OomTaskInit, LOS_INIT_LEVEL_KMOD_TASK);
+LOS_MODULE_INIT(OomTaskInit, LOS_INIT_LEVEL_KMOD_TASK);//初始化内存监控模块
 
 #endif
 

kernel/base/vm/shm.c

@@ -179,9 +179,9 @@ ERROR:
     VM_ERR("ShmInit fail\n");
     return LOS_NOK;
 }
-//共享内存反初始化
-LOS_MODULE_INIT(ShmInit, LOS_INIT_LEVEL_VM_COMPLETE);
 
+LOS_MODULE_INIT(ShmInit, LOS_INIT_LEVEL_VM_COMPLETE);//共享内存模块初始化
+//共享内存反初始化
 UINT32 ShmDeinit(VOID)
 {
     UINT32 ret;

kernel/common/los_hilog.c

@@ -144,12 +144,12 @@ static int HiLogBufferCopy(unsigned char *dst, unsigned dstLen, unsigned char *s
     }
     return retval;
 }
-
+//读取ring buffer
 static int HiLogReadRingBuffer(unsigned char *buffer, size_t bufLen)
 {
     size_t retval;
     size_t bufLeft = HILOG_BUFFER - g_hiLogDev.headOffset;
-    if (bufLeft > bufLen) {
+    if (bufLeft > bufLen) {//计算出读取方向
         retval = HiLogBufferCopy(buffer, bufLen, HiLogBufferHead(), bufLen);
     } else {
         retval = HiLogBufferCopy(buffer, bufLen, HiLogBufferHead(), bufLeft);
@@ -336,4 +336,4 @@ int OsHiLogDriverInit(VOID)
     return register_driver(HILOG_DRIVER, &g_hilogFops, DRIVER_MODE, NULL);//注册字符设备驱动程序,生成inode节点
 }
 
-LOS_MODULE_INIT(OsHiLogDriverInit, LOS_INIT_LEVEL_KMOD_EXTENDED);
+LOS_MODULE_INIT(OsHiLogDriverInit, LOS_INIT_LEVEL_KMOD_EXTENDED);//日志模块初始化

kernel/common/los_init.h

@@ -42,10 +42,10 @@
 #define LOS_INIT_LEVEL_PLATFORM_EARLY               2	//平台早期
 #define LOS_INIT_LEVEL_KMOD_PREVM                   3	//内存模块即将开始
 #define LOS_INIT_LEVEL_VM_COMPLETE                  4	//内存模块完成
-#define LOS_INIT_LEVEL_ARCH                         5	// 架构级
-#define LOS_INIT_LEVEL_PLATFORM                     6	// 平台级
-#define LOS_INIT_LEVEL_KMOD_BASIC                   7	// 基础级
-#define LOS_INIT_LEVEL_KMOD_EXTENDED                8	//
+#define LOS_INIT_LEVEL_ARCH                         5	//架构级
+#define LOS_INIT_LEVEL_PLATFORM                     6	//平台级
+#define LOS_INIT_LEVEL_KMOD_BASIC                   7	//基础级
+#define LOS_INIT_LEVEL_KMOD_EXTENDED                8	//扩展级
 #define LOS_INIT_LEVEL_KMOD_TASK                    9	//任务级
 #define LOS_INIT_LEVEL_FINISH                       10
 
@@ -72,7 +72,7 @@
  * @par Dependency:
  * <ul><li>los_init.h: the header file that contains the API declaration.</li></ul>
  * @see
- */ //将启动模块注册到启动过程
+ */ //将启动模块注册到启动过程,在内核启动过程中注册一个新模块作为内核功能组件的一部分。
 #define LOS_MODULE_INIT(_hook, _level)                  OS_INIT_HOOK_REG(kernel, _hook, _level)
 
 #endif /* _LOS_INIT_H */

kernel/extended/cpup/los_cpup.c

@@ -38,7 +38,7 @@
 
 #ifdef LOSCFG_KERNEL_CPUP
 
-LITE_OS_SEC_BSS STATIC UINT16 cpupSwtmrID;
+LITE_OS_SEC_BSS STATIC UINT16 cpupSwtmrID;	//监测CPU使用情况定时器s
 LITE_OS_SEC_BSS STATIC UINT16 cpupInitFlg = 0;
 LITE_OS_SEC_BSS OsIrqCpupCB *g_irqCpup = NULL;
 LITE_OS_SEC_BSS STATIC UINT16 cpupMaxNum;
@@ -59,7 +59,7 @@ LITE_OS_SEC_BSS STATIC UINT64 cpupIntTimeStart[LOSCFG_KERNEL_CORE_NUM];
 
 #define CPUP_PRE_POS(pos) (((pos) == 0) ? (OS_CPUP_HISTORY_RECORD_NUM - 1) : ((pos) - 1))
 #define CPUP_POST_POS(pos) (((pos) == (OS_CPUP_HISTORY_RECORD_NUM - 1)) ? 0 : ((pos) + 1))
-
+//获取CPU周期
 STATIC UINT64 OsGetCpuCycle(VOID)
 {
     UINT32 high;
@@ -134,7 +134,7 @@ LITE_OS_SEC_TEXT_INIT VOID OsCpupGuard(VOID)
 
     SCHEDULER_UNLOCK(intSave);
 }
-
+//创建cpu使用统计定时器
 LITE_OS_SEC_TEXT_INIT UINT32 OsCpupGuardCreator(VOID)
 {
     (VOID)LOS_SwtmrCreate(LOSCFG_BASE_CORE_TICK_PER_SECOND, LOS_SWTMR_MODE_PERIOD,

kernel/extended/vdso/include/los_vdso.h

@@ -42,7 +42,6 @@
 extern "C" {
 #endif /* __cplusplus */
 #endif /* __cplusplus */
-
 extern UINT32 OsVdsoInit(VOID);
 extern vaddr_t OsVdsoLoad(const LosProcessCB *);
 extern VOID OsVdsoTimevalUpdate(VOID);

kernel/extended/vdso/include/los_vdso_datapage.h

@@ -40,14 +40,14 @@ extern "C" {
 #endif /* __cplusplus */
 #endif /* __cplusplus */
 
-typedef struct {
+typedef struct {//Vdso数据页结构体
     /* Timeval */
     INT64 realTimeSec;
     INT64 realTimeNsec;
     INT64 monoTimeSec;
     INT64 monoTimeNsec;
     /* lock DataPage  0:Unlock State  1:Lock State */
-    UINT64 lockCount;
+    UINT64 lockCount;//数据页被锁数量
 } VdsoDataPage;
 
 #define ELF_HEAD "\177ELF"

kernel/extended/vdso/include/los_vdso_pri.h

@@ -41,13 +41,13 @@ extern "C" {
 #endif /* __cplusplus */
 #endif /* __cplusplus */
 
-#define LITE_VDSO_DATAPAGE __attribute__((section(".data.vdso.datapage")))
+#define LITE_VDSO_DATAPAGE __attribute__((section(".data.vdso.datapage")))//vdso分页数据区
 
 extern VOID OsVdsoTimeGet(VdsoDataPage *);
 
-extern CHAR __vdso_data_start;
-extern CHAR __vdso_text_start;
-extern CHAR __vdso_text_end;
+extern CHAR __vdso_data_start;	//数据段起始地址,他们本质是在内核区的一个虚拟地址
+extern CHAR __vdso_text_start;	//代码段起始地址
+extern CHAR __vdso_text_end;	//代码段结束地址
 
 #ifdef __cplusplus
 #if __cplusplus

kernel/extended/vdso/src/los_vdso.c

@@ -36,14 +36,23 @@
 #include "los_vm_lock.h"
 #include "los_vm_phys.h"
 #include "los_process_pri.h"
+/*
+	vdso 新型系统调用机制 ,虚拟动态共享库VDSO就是Virtual Dynamic Shared Object，
+就是内核提供的虚拟的.so,这类.so文件不在磁盘上，而是包含在内核里面。内核把包含
+某一.so的物理页在程序启动的时候映射入其进程的内存空间，对应的程序就可以当普通的.so来使用里头的函数
 
-LITE_VDSO_DATAPAGE VdsoDataPage g_vdsoDataPage __attribute__((__used__));
+参考:http://lishiwen4.github.io/linux/vdso-and-syscall
+	 https://vvl.me/2019/06/linux-syscall-and-vsyscall-vdso-in-x86/
 
-STATIC size_t g_vdsoSize;
+#cat /proc/self/maps
+*/
+LITE_VDSO_DATAPAGE VdsoDataPage g_vdsoDataPage __attribute__((__used__));//使用这个数据区
 
+STATIC size_t g_vdsoSize;
+//vdso初始化
 UINT32 OsVdsoInit(VOID)
 {
-    g_vdsoSize = &__vdso_text_end - &__vdso_data_start;
+    g_vdsoSize = &__vdso_text_end - &__vdso_data_start;//vDSO 会映射两块内存区域：代码段 [vdso]，只读数据区 [vvar] 数据页
 
     if (memcmp((CHAR *)(&__vdso_text_start), ELF_HEAD, ELF_HEAD_LEN)) {
         PRINT_ERR("VDSO Init Failed!\n");
@@ -53,7 +62,8 @@ UINT32 OsVdsoInit(VOID)
 }
 
 LOS_MODULE_INIT(OsVdsoInit, LOS_INIT_LEVEL_KMOD_EXTENDED);
-
+//映射,这里先通过内核地址找到 vdso的物理地址,再将物理地址映射到进程的线性区.
+//结论是每个进程都可以拥有自己的 vdso区,映射到同一个块物理地址.
 STATIC INT32 OsVdsoMap(LosVmSpace *space, size_t len, PADDR_T paddr, VADDR_T vaddr, UINT32 flag)
 {
     STATUS_T ret;
@@ -70,26 +80,26 @@ STATIC INT32 OsVdsoMap(LosVmSpace *space, size_t len, PADDR_T paddr, VADDR_T vad
     }
     return LOS_OK;
 }
-
+//为每个进程加载 vsdo
 vaddr_t OsVdsoLoad(const LosProcessCB *processCB)
 {
     INT32 ret = -1;
     LosVmMapRegion *vdsoRegion = NULL;
     UINT32 flag = VM_MAP_REGION_FLAG_PERM_USER | VM_MAP_REGION_FLAG_PERM_READ | VM_MAP_REGION_FLAG_PERM_EXECUTE;
-
+	//用户区,可读可执行
     if ((processCB == NULL) || (processCB->vmSpace == NULL)) {
         return 0;
     }
 
     (VOID)LOS_MuxAcquire(&processCB->vmSpace->regionMux);
-
+	//由虚拟空间提供加载内存
     vdsoRegion = LOS_RegionAlloc(processCB->vmSpace, 0, g_vdsoSize, flag, 0);
     if (vdsoRegion == NULL) {
         PRINT_ERR("%s %d, region alloc failed in vdso load\n", __FUNCTION__, __LINE__);
         goto LOCK_RELEASE;
     }
-    vdsoRegion->regionFlags |= VM_MAP_REGION_FLAG_VDSO;
-
+    vdsoRegion->regionFlags |= VM_MAP_REGION_FLAG_VDSO;//标识为 vdso区
+	//为vsdo做好映射,如此通过访问进程的虚拟地址就可以访问到真正的vsdo
     ret = OsVdsoMap(processCB->vmSpace, g_vdsoSize, LOS_PaddrQuery((VOID *)(&__vdso_data_start)),
                     vdsoRegion->range.base, flag);
     if (ret != LOS_OK) {
@@ -107,22 +117,22 @@ LOCK_RELEASE:
     }
     return 0;
 }
-
+//对数据页加锁
 STATIC VOID LockVdsoDataPage(VdsoDataPage *vdsoDataPage)
 {
     vdsoDataPage->lockCount = 1;
     DMB;
 }
-
+//对数据页加锁
 STATIC VOID UnlockVdsoDataPage(VdsoDataPage *vdsoDataPage)
 {
     DMB;
     vdsoDataPage->lockCount = 0;
 }
-
+//更新时间,
 VOID OsVdsoTimevalUpdate(VOID)
 {
-    VdsoDataPage *kVdsoDataPage = (VdsoDataPage *)(&__vdso_data_start);
+    VdsoDataPage *kVdsoDataPage = (VdsoDataPage *)(&__vdso_data_start);//获取vdso 数据区
 
     LockVdsoDataPage(kVdsoDataPage);
     OsVdsoTimeGet(kVdsoDataPage);

kernel/extended/vdso/src/los_vdso_text.S

@@ -27,8 +27,8 @@
  * 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.
- */
+ */ 
     .globl __vdso_text_start
     .section .data.vdso.text
-__vdso_text_start:
-    .incbin "../usr/OHOS-vdso.so"
+__vdso_text_start: @vdso代码段入口
+    .incbin "../usr/OHOS-vdso.so" @ include bin的意思
\ No newline at end of file

shell/full/include/dmesg_pri.h

@@ -45,7 +45,7 @@ extern "C" {
 /*
  * The dmesg buffer is start with this info structure, then the log.
  */
-typedef struct {
+typedef struct {//dmesg信息管理器,环形buf
     UINT32 logSize; /* The size of log in buffer */
     UINT32 logHead; /* The index of the first log data. Data_out_flag */
     UINT32 logTail; /* The index where to write, write in and plus one. Data_it_flag */

shell/full/src/base/shell_lk.c

@@ -43,7 +43,7 @@
 
 #ifdef LOSCFG_SHELL_LK
 
-typedef enum {
+typedef enum {//模块等级
     MODULE0 = 0,
     MODULE1 = 1,
     MODULE2 = 2,
@@ -52,9 +52,9 @@ typedef enum {
 } MODULE_FLAG;
 
 typedef struct {
-    INT32 module_level;
-    INT32 trace_level;
-    FILE *fp;
+    INT32 module_level;//模块等级
+    INT32 trace_level;//跟踪等级
+    FILE *fp;		  //文件描述结构体
 } Logger;
 
 STATIC INT32 g_tracelevel;
@@ -119,7 +119,32 @@ FILE *OsLogFpGet(VOID)
 {
     return g_logger.fp;
 }
+/**************************************************************
+log命令用于修改&查询日志配置,即选择打印哪种日志?
+该命令依赖于LOSCFG_SHELL_LK，使用时通过menuconfig在配置项中开启"Enable Shell lk"：
 
+Debug ---> Enable a Debug Version ---> Enable Shell ---> Enable Shell lK。
+
+log level命令用于配置日志的打印等级，包括6个等级
+
+TRACE_EMG = 0,
+
+TRACE_COMMON = 1,
+
+TRACE_ERROR = 2,
+
+TRACE_WARN = 3,
+
+TRACE_INFO = 4,
+
+TRACE_DEBUG = 5
+
+若level不在有效范围内，会打印提示信息。
+
+若log level命令不加[levelNum]参数，则默认查看当前打印等级，并且提示使用方法。
+
+输入log level 4
+***************************************************************/
 INT32 CmdLog(INT32 argc, const CHAR **argv)
 {
     size_t level;
@@ -166,7 +191,7 @@ INT32 CmdLog(INT32 argc, const CHAR **argv)
 }
 
 #ifdef LOSCFG_SHELL_DMESG
-STATIC INLINE VOID OsLogCycleRecord(INT32 level)
+STATIC INLINE VOID OsLogCycleRecord(INT32 level)//日志循环记录
 {
     UINT32 tmpLen;
     if (level != LOS_COMMON_LEVEL && (level > LOS_EMG_LEVEL && level <= LOS_TRACE_LEVEL)) {
@@ -176,7 +201,7 @@ STATIC INLINE VOID OsLogCycleRecord(INT32 level)
     }
 }
 #endif
-
+//默认打印函数,用于回调函数
 VOID OsLkDefaultFunc(INT32 level, const CHAR *func, INT32 line, const CHAR *fmt, va_list ap)
 {
     if (level > OsLkTraceLvGet()) {
@@ -193,7 +218,7 @@ VOID OsLkDefaultFunc(INT32 level, const CHAR *func, INT32 line, const CHAR *fmt,
     }
     LkDprintf(fmt, ap);
 }
-
+//打印
 VOID LOS_LkPrint(INT32 level, const CHAR *func, INT32 line, const CHAR *fmt, ...)
 {
     va_list ap;
@@ -203,12 +228,12 @@ VOID LOS_LkPrint(INT32 level, const CHAR *func, INT32 line, const CHAR *fmt, ...
         va_end(ap);
     }
 }
-
+//设置回调函数
 VOID LOS_LkRegHook(LK_FUNC hook)
 {
     g_osLkHook = hook;
 }
-
+//内核日志初始化
 UINT32 OsLkLoggerInit(VOID)
 {
     (VOID)memset_s(&g_logger, sizeof(Logger), 0, sizeof(Logger));
@@ -224,6 +249,6 @@ UINT32 OsLkLoggerInit(VOID)
 SHELLCMD_ENTRY(log_shellcmd, CMD_TYPE_EX, "log", 1, (CmdCallBackFunc)CmdLog);
 #endif
 
-LOS_MODULE_INIT(OsLkLoggerInit, LOS_INIT_LEVEL_EARLIEST);
+LOS_MODULE_INIT(OsLkLoggerInit, LOS_INIT_LEVEL_EARLIEST);//日志模块初始化
 
 #endif

shell/full/src/cmds/dmesg.c

@@ -69,9 +69,9 @@ LITE_OS_SEC_BSS STATIC SPIN_LOCK_INIT(g_dmesgSpin);
 STATIC DmesgInfo *g_dmesgInfo = NULL;
 STATIC UINT32 g_logBufSize = 0;
 STATIC VOID *g_mallocAddr = NULL;
-STATIC UINT32 g_dmesgLogLevel = 3;
-STATIC UINT32 g_consoleLock = 0;
-STATIC UINT32 g_uartLock = 0;
+STATIC UINT32 g_dmesgLogLevel = 3;//日志等级
+STATIC UINT32 g_consoleLock = 0;//用于关闭和打开控制台
+STATIC UINT32 g_uartLock = 0;//用于关闭和打开串口
 STATIC const CHAR *g_levelString[] = {
     "EMG",
     "COMMON",
@@ -80,22 +80,22 @@ STATIC const CHAR *g_levelString[] = {
     "INFO",
     "DEBUG"
 };
-
+//关闭控制台
 STATIC VOID OsLockConsole(VOID)
 {
     g_consoleLock = 1;
 }
-
+//打开控制台
 STATIC VOID OsUnlockConsole(VOID)
 {
     g_consoleLock = 0;
 }
-
+//关闭串口
 STATIC VOID OsLockUart(VOID)
 {
     g_uartLock = 1;
 }
-
+//打开串口
 STATIC VOID OsUnlockUart(VOID)
 {
     g_uartLock = 0;
@@ -300,7 +300,7 @@ UINT32 OsCheckUartLock(VOID)
 {
     return g_uartLock;
 }
-
+//初始化 dmesg
 UINT32 OsDmesgInit(VOID)
 {
     CHAR* buffer = NULL;
@@ -708,7 +708,26 @@ INT32 LOS_DmesgToFile(CHAR *filename)
 }
 #endif
 
+}
+/*************************************************************
+dmesg全称是display message (or display driver)，即显示信息。
+
+dmesg命令用于控制内核dmesg缓存区
+dmesg命令用于显示开机信息
+该命令依赖于LOSCFG_SHELL_DMESG，使用时通过menuconfig在配置项中开启"Enable Shell dmesg"：
 
+Debug ---> Enable a Debug Version ---> Enable Shell ---> Enable Shell dmesg
+
+dmesg参数缺省时，默认打印缓存区内容。
+
+各“ - ”选项不能混合使用。
+
+写入文件需确保已挂载文件系统。
+关闭串口打印会影响shell使用，建议先连接telnet再尝试关闭串口。
+
+dmesg > /usr/dmesg.log。
+
+**************************************************************/
 INT32 OsShellCmdDmesg(INT32 argc, const CHAR **argv)
 {
     if (argc == 1) {
@@ -720,24 +739,24 @@ INT32 OsShellCmdDmesg(INT32 argc, const CHAR **argv)
             goto ERR_OUT;
         }
 
-        if (!strcmp(argv[1], "-c")) {
+        if (!strcmp(argv[1], "-c")) {//打印缓存区内容并清空缓存区
             PRINTK("\n");
-            OsLogShow();
+            OsLogShow();//打印缓存区内容
             LOS_DmesgClear();
             return LOS_OK;
-        } else if (!strcmp(argv[1], "-C")) {
+        } else if (!strcmp(argv[1], "-C")) {//清空缓存区。
             LOS_DmesgClear();
             return LOS_OK;
-        } else if (!strcmp(argv[1], "-D")) {
+        } else if (!strcmp(argv[1], "-D")) {//关闭控制台打印。
             OsLockConsole();
             return LOS_OK;
-        } else if (!strcmp(argv[1], "-E")) {
+        } else if (!strcmp(argv[1], "-E")) {///开启控制台打印。
             OsUnlockConsole();
             return LOS_OK;
-        } else if (!strcmp(argv[1], "-L")) {
+        } else if (!strcmp(argv[1], "-L")) {//关闭串口打印
             OsLockUart();
             return LOS_OK;
-        } else if (!strcmp(argv[1], "-U")) {
+        } else if (!strcmp(argv[1], "-U")) {//开启串口打印
             OsUnlockUart();
             return LOS_OK;
         }
@@ -746,7 +765,7 @@ INT32 OsShellCmdDmesg(INT32 argc, const CHAR **argv)
             goto ERR_OUT;
         }
 
-        if (!strcmp(argv[1], ">")) {
+        if (!strcmp(argv[1], ">")) {//将缓存区内容写入文件
             if (LOS_DmesgToFile((CHAR *)argv[2]) < 0) { /* 2:index of parameters */
                 PRINTK("Dmesg write log to %s fail \n", argv[2]); /* 2:index of parameters */
                 return -1;
@@ -754,9 +773,9 @@ INT32 OsShellCmdDmesg(INT32 argc, const CHAR **argv)
                 PRINTK("Dmesg write log to %s success \n", argv[2]); /* 2:index of parameters */
                 return LOS_OK;
             }
-        } else if (!strcmp(argv[1], "-l")) {
+        } else if (!strcmp(argv[1], "-l")) {//设置缓存等级
             return OsDmesgLvSet(argv[2]); /* 2:index of parameters */
-        } else if (!strcmp(argv[1], "-s")) {
+        } else if (!strcmp(argv[1], "-s")) {//设置缓存区大小 size是要设置的大小
             return OsDmesgMemSizeSet(argv[2]); /* 2:index of parameters */
         }
     }
@@ -764,9 +783,8 @@ INT32 OsShellCmdDmesg(INT32 argc, const CHAR **argv)
 ERR_OUT:
     PRINTK("dmesg: invalid option or parameter.\n");
     return -1;
-}
 
 SHELLCMD_ENTRY(dmesg_shellcmd, CMD_TYPE_STD, "dmesg", XARGS, (CmdCallBackFunc)OsShellCmdDmesg);
-LOS_MODULE_INIT(OsDmesgInit, LOS_INIT_LEVEL_EARLIEST);
+LOS_MODULE_INIT(OsDmesgInit, LOS_INIT_LEVEL_EARLIEST);//在非常早期调用
 
 #endif

syscall/los_syscall.c

@@ -82,7 +82,7 @@ typedef UINT32 (*SyscallFun7)(UINT32, UINT32, UINT32, UINT32, UINT32, UINT32, UI
 static UINTPTR g_syscallHandle[SYS_CALL_NUM] = {0};	//系统调用入口函数注册
 static UINT8 g_syscallNArgs[(SYS_CALL_NUM + 1) / NARG_PER_BYTE] = {0};//保存系统调用对应的参数数量
 
-//系统调用初始化,完成对系统调用的注册
+//系统调用初始化,完成对系统调用的注册,将系统调用添加到全局变量中 g_syscallHandle,g_syscallNArgs
 void OsSyscallHandleInit(void)
 {
 #define SYSCALL_HAND_DEF(id, fun, rType, nArg)                                             \
@@ -95,7 +95,7 @@ void OsSyscallHandleInit(void)
 #undef SYSCALL_HAND_DEF
 }
 
-LOS_MODULE_INIT(OsSyscallHandleInit, LOS_INIT_LEVEL_KMOD_EXTENDED);
+LOS_MODULE_INIT(OsSyscallHandleInit, LOS_INIT_LEVEL_KMOD_EXTENDED);//注册系统调用模块
 /* The SYSCALL ID is in R7 on entry.  Parameters follow in R0..R6 */
 /******************************************************************
 由汇编调用,见于 los_hw_exc.s    / BLX    OsArmA32SyscallHandle
@@ -125,7 +125,7 @@ VOID OsArmA32SyscallHandle(TaskContext *regs)
         return;
     }
 	//regs[0-6] 记录系统调用的参数,这也是由R7寄存器保存系统调用号的原因
-    OsSigIntLock();
+    OsSigIntLock();//禁止响应信号
     switch (nArgs) {//参数的个数 
         case ARG_NUM_0:
         case ARG_NUM_1:
@@ -143,8 +143,8 @@ VOID OsArmA32SyscallHandle(TaskContext *regs)
             ret = (*(SyscallFun7)handle)(regs->R0, regs->R1, regs->R2, regs->R3, regs->R4, regs->R5, regs->R6);
     }
 
-    regs->R0 = ret;
-    OsSigIntUnlock();
+    regs->R0 = ret;//系统返回值,保存在R0寄存器
+    OsSigIntUnlock();//打开响应信号
 
     return;
 }

zzz/git/push.sh

 git add -A
-git commit -m  '上传linux经典书籍
+git commit -m  '对 vdso 实现注解 
     百万汉字注解 + 百篇博客分析 => 挖透鸿蒙内核源码
     国内:https://weharmony.21cloudbox.com
     国外:https://weharmony.github.io