开始对IPC Futex 部分代码注释,鸿蒙提供了多种IPC方式

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项目给鸿蒙内核源码逐行加上中文注解,详细阐述框架和代码细节, 精读 HarmonyOS 内核源码, 将迅速拔高对计算机整体理解,从此高屋建瓴看问题.

kernel/base/core/los_process.c

@@ -1522,7 +1522,7 @@ LITE_OS_SEC_TEXT UINT32 OsExecRecycleAndInit(LosProcessCB *processCB, const CHAR
     delete_files(OsCurrProcessGet(), (struct files_struct *)oldFiles);
 #endif
 
-    OsSwtmrRecycle(processCB->processID);
+    OsSwtmrRecycle(processCB->processID);//定时器回收
     processCB->timerID = (timer_t)(UINTPTR)MAX_INVALID_TIMER_VID;
 
 #ifdef LOSCFG_SECURITY_VID

kernel/extended/dynload/include/los_load_elf.h

@@ -84,7 +84,7 @@ extern "C" {
 #define PF_R                                0x4
 #define PF_W                                0x2
 #define PF_X                                0x1
-
+//ELF 加载信息 可执行和可链接格式(Executable and Linkable Format，缩写为ELF)，常被称为ELF格式
 typedef struct {
     const CHAR   *fileName;
     CHAR         *execName;
@@ -99,19 +99,19 @@ typedef struct {
     UINT32       stackSize;
     INT32        stackProt;
     UINTPTR      loadAddr;
-    UINTPTR      elfEntry;
-    LD_ELF_EHDR  elfEhdr;
-    LD_ELF_PHDR  *elfPhdr;
+    UINTPTR      elfEntry;	//入口函数位置
+    LD_ELF_EHDR  elfEhdr;	//ELF head
+    LD_ELF_PHDR  *elfPhdr;	//ELF 程序头表
     UINT32       execFileLen;
     INT32        execFD;
-    LD_ELF_EHDR  interpELFEhdr;
+    LD_ELF_EHDR  interpELFEhdr;		//解释器段 ( 动态链接器路径 )
     LD_ELF_PHDR  *interpELFPhdr;
     UINT32       interpFileLen;
     INT32        interpFD;
     UINTPTR      topOfMem;
     UINTPTR      oldFiles;
-    LosVmSpace   *newSpace;
-    LosVmSpace   *oldSpace;
+    LosVmSpace   *newSpace;	//新的虚拟空间，新开一个空间，把ELF各segment加载到这个虚拟空间，再切换MMU上下文，开始ELF的运行
+    LosVmSpace   *oldSpace;	//老的虚拟空间，切当前进程的壳运行，由此保存当前进程的虚拟空间
 #ifdef LOSCFG_ASLR
     INT32        randomDevFD;
 #endif

kernel/extended/dynload/src/los_exec_elf.c

@@ -92,7 +92,7 @@ STATIC INT32 OsCopyUserParam(ELFLoadInfo *loadInfo, const CHAR *fileName, CHAR *
     UINT32 strLen;
     errno_t err;
 
-    if (LOS_IsUserAddress((VADDR_T)(UINTPTR)fileName)) {//在用户空间
+    if (LOS_IsUserAddress((VADDR_T)(UINTPTR)fileName)) {//参数文件名存放在用户空间
         err = LOS_StrncpyFromUser(kfileName, fileName, PATH_MAX + 1);
         if (err == -EFAULT) {
             return err;
@@ -100,7 +100,7 @@ STATIC INT32 OsCopyUserParam(ELFLoadInfo *loadInfo, const CHAR *fileName, CHAR *
             PRINT_ERR("%s[%d], filename len exceeds maxlen: %d\n", __FUNCTION__, __LINE__, PATH_MAX);
             return -ENAMETOOLONG;
         }
-    } else if (LOS_IsKernelAddress((VADDR_T)(UINTPTR)fileName)) {//在内核空间
+    } else if (LOS_IsKernelAddress((VADDR_T)(UINTPTR)fileName)) {//参数文件存在内核空间
         strLen = strlen(fileName);
         err = memcpy_s(kfileName, PATH_MAX, fileName, strLen);//从filename -> kfilename 
         if (err != EOK) {
@@ -114,7 +114,7 @@ STATIC INT32 OsCopyUserParam(ELFLoadInfo *loadInfo, const CHAR *fileName, CHAR *
     loadInfo->fileName = kfileName;
     return LOS_OK;
 }
-
+//运行一个执行文件 .elf
 INT32 LOS_DoExecveFile(const CHAR *fileName, CHAR * const *argv, CHAR * const *envp)
 {
     ELFLoadInfo loadInfo = { 0 };//ELF加载信息结构体
@@ -127,7 +127,7 @@ INT32 LOS_DoExecveFile(const CHAR *fileName, CHAR * const *argv, CHAR * const *e
     LosVmPage *vmPage = NULL;
 
     if ((fileName == NULL) || ((argv != NULL) && !LOS_IsUserAddress((VADDR_T)(UINTPTR)argv)) ||
-        ((envp != NULL) && !LOS_IsUserAddress((VADDR_T)(UINTPTR)envp))) {
+        ((envp != NULL) && !LOS_IsUserAddress((VADDR_T)(UINTPTR)envp))) {//argv需要再用户空间
         return -EINVAL;
     }
     ret = OsCopyUserParam(&loadInfo, fileName, kfileName, PATH_MAX);//将文件名拷贝到内核空间,PATH_MAX = 256
@@ -165,12 +165,12 @@ INT32 LOS_DoExecveFile(const CHAR *fileName, CHAR * const *argv, CHAR * const *e
         LOS_PhysPagesFreeContiguous(virtTtb, 1);
         return -ENOMEM;
     }
-    LOS_ListAdd(&loadInfo.newSpace->archMmu.ptList, &(vmPage->node));
+    LOS_ListAdd(&loadInfo.newSpace->archMmu.ptList, &(vmPage->node));//用vmPage->node挂到  ptlist, vmPage 就是 L1表
 
-    loadInfo.argv = argv;
+    loadInfo.argv = argv;//
     loadInfo.envp = envp;
 
-    ret = OsLoadELFFile(&loadInfo);
+    ret = OsLoadELFFile(&loadInfo);//虚拟空间已经准备好了，该开始加载ELF文件到虚拟空间了。
     if (ret != LOS_OK) {
         return ret;
     }

kernel/extended/dynload/src/los_load_elf.c

@@ -141,7 +141,7 @@ STATIC INT32 OsVerifyELFPhdr(const LD_ELF_PHDR *phdr)
 
     return LOS_OK;
 }
-
+//ELF加载初始化
 STATIC INT32 OsELFLoadInit(const CHAR *fileName, ELFLoadInfo *loadInfo)
 {
     INT32 ret;
@@ -971,19 +971,19 @@ STATIC INT32 OsLoadELFSegment(ELFLoadInfo *loadInfo)
 
     return LOS_OK;
 }
-
+//擦除虚拟空间
 STATIC VOID OsFlushAspace(ELFLoadInfo *loadInfo)
 {
-    LosProcessCB *processCB = OsCurrProcessGet();
+    LosProcessCB *processCB = OsCurrProcessGet();//获取当前进程
 
     OsExecDestroyTaskGroup();
 
-    loadInfo->oldSpace = processCB->vmSpace;
-    processCB->vmSpace = loadInfo->newSpace;
-    processCB->vmSpace->heapBase += OsGetRndOffset(loadInfo);
-    processCB->vmSpace->heapNow = processCB->vmSpace->heapBase;
-    processCB->vmSpace->mapBase += OsGetRndOffset(loadInfo);
-    LOS_ArchMmuContextSwitch(&OsCurrProcessGet()->vmSpace->archMmu);
+    loadInfo->oldSpace = processCB->vmSpace;//当前进程的虚拟空间记录下来
+    processCB->vmSpace = loadInfo->newSpace;//新空间换成当前进程的虚拟空间，牛逼借壳上市
+    processCB->vmSpace->heapBase += OsGetRndOffset(loadInfo);//堆区基地址
+    processCB->vmSpace->heapNow = processCB->vmSpace->heapBase;//堆区现地址
+    processCB->vmSpace->mapBase += OsGetRndOffset(loadInfo);//映射区基地址
+    LOS_ArchMmuContextSwitch(&OsCurrProcessGet()->vmSpace->archMmu);//mmu上下文切换
 }
 
 STATIC VOID OsDeInitLoadInfo(ELFLoadInfo *loadInfo)
@@ -1014,17 +1014,17 @@ STATIC VOID OsDeInitFiles(ELFLoadInfo *loadInfo)
     delete_files_snapshot((struct files_struct *)loadInfo->oldFiles);
 #endif
 }
-
+//加载ELF文件
 INT32 OsLoadELFFile(ELFLoadInfo *loadInfo)
 {
     INT32 ret;
 
-    ret = OsELFLoadInit(loadInfo->fileName, loadInfo);
+    ret = OsELFLoadInit(loadInfo->fileName, loadInfo);//ELF加载初始化
     if (ret != LOS_OK) {
         goto OUT;
     }
 
-    ret = OsLoadProgramHdrs(loadInfo);
+    ret = OsLoadProgramHdrs(loadInfo);//加载程序头
     if (ret != LOS_OK) {
         goto OUT;
     }
@@ -1039,12 +1039,12 @@ INT32 OsLoadELFFile(ELFLoadInfo *loadInfo)
         goto OUT;
     }
 
-    (VOID)OsFlushAspace(loadInfo);
+    (VOID)OsFlushAspace(loadInfo);//冲洗干净空间，这里的意思就是打扫干净房子，准备放东西进来。
 
-    ret = OsLoadELFSegment(loadInfo);
-    if (ret != LOS_OK) {
-        OsCurrProcessGet()->vmSpace = loadInfo->oldSpace;
-        LOS_ArchMmuContextSwitch(&OsCurrProcessGet()->vmSpace->archMmu);
+    ret = OsLoadELFSegment(loadInfo);//加载ELF各个段，放东西进虚拟空间
+    if (ret != LOS_OK) {//如果加载失败
+        OsCurrProcessGet()->vmSpace = loadInfo->oldSpace;//之前的虚拟空间还给当前进程
+        LOS_ArchMmuContextSwitch(&OsCurrProcessGet()->vmSpace->archMmu);//切换mmu上下文
         goto OUT;
     }
 

kernel/extended/liteipc/hm_liteipc.c

@@ -73,7 +73,7 @@ HandleInfo g_cmsTask;
 HandleInfo g_serviceHandleMap[MAX_SERVICE_NUM];
 #endif
 STATIC LOS_DL_LIST g_ipcPendlist;
-STATIC LOS_DL_LIST g_ipcUsedNodelist[LOSCFG_BASE_CORE_PROCESS_LIMIT];
+STATIC LOS_DL_LIST g_ipcUsedNodelist[LOSCFG_BASE_CORE_PROCESS_LIMIT];//==进程数量 64个
 
 /* ipc lock */
 SPIN_LOCK_INIT(g_ipcSpin);
@@ -216,7 +216,7 @@ VOID IpcBacktrace(VOID)
     }
 }
 #endif
-
+//liteIpc 初始化
 LITE_OS_SEC_TEXT_INIT UINT32 LiteIpcInit(VOID)
 {
     UINT32 ret, i;

syscall/fs_syscall.c

@@ -377,7 +377,7 @@ OUT:
     }
     return ret;
 }
-
+//系统调用，运行.elf
 int SysExecve(const char *fileName, char *const *argv, char *const *envp)
 {
     return LOS_DoExecveFile(fileName, argv, envp);

zzz/test/gcc.sh

-gcc -o main main.c
-.\main.out
\ No newline at end of file

zzz/test/main.c

@@ -43,11 +43,16 @@ void round1(){
     //printf("ROUNDUP %d\n",ROUNDUP(9, 2));
     //printf("ROUNDDOWN %d\n",ROUNDDOWN(9, 2));
 }
-
+int     aw;
+int     bw=99;
+void Print(){
+    printf("ROUNDUP %d\n",ROUNDUP(0x00000200+512,1024));
+}
 int main()
 {
-    printf("ROUNDUP %d\n",ROUNDUP(0x00000200+512,1024));
-    
+    int b = 0;
+    //printf("ROUNDUP %d\n",ROUNDUP(0x00000200+512,1024));
+    Print();
     return 0;
 }
 

zzz/test/main.s

-	.file	"main.c"
-	.text
-	.def	__main;	.scl	2;	.type	32;	.endef
-	.section .rdata,"dr"
-.LC0:
-	.ascii "ROUNDUP %d\12\0"
-.LC1:
-	.ascii "ROUNDDOWN %d\12\0"
-	.text
-	.globl	main
-	.def	main;	.scl	2;	.type	32;	.endef
-	.seh_proc	main
-main:
-.LFB28:
-	pushq	%rbp
-	.seh_pushreg	%rbp
-	movq	%rsp, %rbp
-	.seh_setframe	%rbp, 0
-	subq	$32, %rsp
-	.seh_stackalloc	32
-	.seh_endprologue
-	call	__main
-	movl	$10, %edx
-	leaq	.LC0(%rip), %rcx
-	call	printf
-	movl	$8, %edx
-	leaq	.LC1(%rip), %rcx
-	call	printf
-	movl	$0, %eax
-	addq	$32, %rsp
-	popq	%rbp
-	ret
-	.seh_endproc
-	.ident	"GCC: (x86_64-win32-seh-rev0, Built by MinGW-W64 project) 8.1.0"
-	.def	printf;	.scl	2;	.type	32;	.endef