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https://github.com/DragonOS-Community/DragonOS.git
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new: 内核态fork
This commit is contained in:
fslongjin
parent
311a6181b5
commit
2fd21e0395
@ -3,7 +3,7 @@ CFLAGS += -I .
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kernel_common_subdirs:=libELF math
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all: glib.o printk.o cpu.o bitree.o kfifo.o wait_queue.o mutex.o wait.o
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all: glib.o printk.o cpu.o bitree.o kfifo.o wait_queue.o mutex.o wait.o unistd.o
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@list='$(kernel_common_subdirs)'; for subdir in $$list; do \
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echo "make all in $$subdir";\
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cd $$subdir;\
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@ -34,3 +34,6 @@ mutex.o: mutex.c
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wait.o: sys/wait.c
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gcc $(CFLAGS) -c sys/wait.c -o sys/wait.o
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unistd.o: unistd.c
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gcc $(CFLAGS) -c unistd.c -o unistd.o
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21
kernel/common/unistd.c
Normal file
21
kernel/common/unistd.c
Normal file
@ -0,0 +1,21 @@
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#include <common/unistd.h>
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/**
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* @brief fork当前进程
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*
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* @return pid_t
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*/
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pid_t fork(void)
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{
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return (pid_t)enter_syscall_int(SYS_FORK, 0, 0, 0, 0, 0, 0, 0, 0);
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}
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/**
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* @brief vfork当前进程
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*
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* @return pid_t
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*/
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pid_t vfork(void)
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{
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return (pid_t)enter_syscall_int(SYS_VFORK, 0, 0, 0, 0, 0, 0, 0, 0);
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}
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@ -12,3 +12,17 @@
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#include <syscall/syscall.h>
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#include <syscall/syscall_num.h>
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/**
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* @brief fork当前进程
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*
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* @return pid_t
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*/
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pid_t fork(void);
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/**
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* @brief vfork当前进程
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*
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* @return pid_t
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*/
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pid_t vfork(void);
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@ -16,6 +16,8 @@
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#include <syscall/syscall.h>
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#include <syscall/syscall_num.h>
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#include <sched/sched.h>
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#include <common/unistd.h>
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#include <debug/traceback/traceback.h>
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#include <ktest/ktest.h>
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@ -121,7 +123,6 @@ void __switch_to(struct process_control_block *prev, struct process_control_bloc
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__asm__ __volatile__("movq %0, %%fs \n\t" ::"a"(next->thread->fs));
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__asm__ __volatile__("movq %0, %%gs \n\t" ::"a"(next->thread->gs));
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// wrmsr(0x175, next->thread->rbp);
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}
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/**
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@ -375,7 +376,7 @@ ul do_execve(struct pt_regs *regs, char *path, char *argv[], char *envp[])
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strncpy((char *)(str_addr - argv_len), argv[argc], argv_len - 1);
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str_addr -= argv_len;
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dst_argv[argc] = (char *)str_addr;
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//字符串加上结尾字符
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// 字符串加上结尾字符
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((char *)str_addr)[argv_len] = '\0';
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}
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@ -422,9 +423,20 @@ ul initial_kernel_thread(ul arg)
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ktest_start(ktest_test_kfifo, 0),
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ktest_start(ktest_test_mutex, 0),
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};
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kinfo("Waiting test thread exit...");
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// 等待测试进程退出
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for(int i=0;i<sizeof(tpid)/sizeof(uint64_t);++i)
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for (int i = 0; i < sizeof(tpid) / sizeof(uint64_t); ++i)
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waitpid(tpid[i], NULL, NULL);
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kinfo("All test done.");
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// pid_t p = fork();
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// if (p == 0)
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// {
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// kdebug("in subproc, rflags=%#018lx", get_rflags());
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// while (1)
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// usleep(1000);
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// }
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// kdebug("subprocess pid=%d", p);
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// 准备切换到用户态
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struct pt_regs *regs;
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@ -439,8 +451,6 @@ ul initial_kernel_thread(ul arg)
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// 主动放弃内核线程身份
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current_pcb->flags &= (~PF_KTHREAD);
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kdebug("in initial_kernel_thread: flags=%ld", current_pcb->flags);
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// current_pcb->mm->pgd = kmalloc(PAGE_4K_SIZE, 0);
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// memset((void*)current_pcb->mm->pgd, 0, PAGE_4K_SIZE);
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regs = (struct pt_regs *)current_pcb->thread->rsp;
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// kdebug("current_pcb->thread->rsp=%#018lx", current_pcb->thread->rsp);
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@ -492,7 +502,7 @@ ul process_do_exit(ul code)
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sched_cfs();
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while (1)
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hlt();
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pause();
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}
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/**
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@ -604,11 +614,9 @@ unsigned long do_fork(struct pt_regs *regs, unsigned long clone_flags, unsigned
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{
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int retval = 0;
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struct process_control_block *tsk = NULL;
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// kdebug("222\tregs.rip = %#018lx", regs->rip);
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// 为新的进程分配栈空间，并将pcb放置在底部
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tsk = (struct process_control_block *)kmalloc(STACK_SIZE, 0);
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// kdebug("struct process_control_block ADDRESS=%#018lx", (uint64_t)tsk);
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if (tsk == NULL)
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{
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@ -620,12 +628,13 @@ unsigned long do_fork(struct pt_regs *regs, unsigned long clone_flags, unsigned
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// 将当前进程的pcb复制到新的pcb内
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memcpy(tsk, current_pcb, sizeof(struct process_control_block));
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// kdebug("current_pcb->flags=%#010lx", current_pcb->flags);
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// 将进程加入循环链表
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// 初始化进程的循环链表结点
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list_init(&tsk->list);
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// list_add(&initial_proc_union.pcb.list, &tsk->list);
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// 判断是否为内核态调用fork
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if (current_pcb->flags & PF_KTHREAD && stack_start != 0)
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tsk->flags |= PF_KFORK;
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tsk->priority = 2;
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tsk->preempt_count = 0;
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@ -647,7 +656,6 @@ unsigned long do_fork(struct pt_regs *regs, unsigned long clone_flags, unsigned
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wait_queue_init(&tsk->wait_child_proc_exit, NULL);
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list_init(&tsk->list);
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// list_add(&initial_proc_union.pcb.list, &tsk->list);
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retval = -ENOMEM;
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@ -670,6 +678,8 @@ unsigned long do_fork(struct pt_regs *regs, unsigned long clone_flags, unsigned
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// 拷贝成功
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retval = tsk->pid;
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tsk->flags &= ~PF_KFORK;
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// 唤醒进程
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process_wakeup(tsk);
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@ -811,7 +821,6 @@ uint64_t process_copy_mm(uint64_t clone_flags, struct process_control_block *pcb
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// 与父进程共享内存空间
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if (clone_flags & CLONE_VM)
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{
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// kdebug("copy_vm\t current_pcb->mm->pgd=%#018lx", current_pcb->mm->pgd);
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pcb->mm = current_pcb->mm;
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return retval;
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@ -973,6 +982,48 @@ uint64_t process_exit_mm(struct process_control_block *pcb)
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return 0;
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}
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/**
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* @brief 重写内核栈中的rbp地址
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*
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* @param new_regs 子进程的reg
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* @param new_pcb 子进程的pcb
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* @return int
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*/
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static int process_rewrite_rbp(struct pt_regs *new_regs, struct process_control_block *new_pcb)
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{
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uint64_t new_top = ((uint64_t)new_pcb) + STACK_SIZE;
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uint64_t old_top = (uint64_t)(current_pcb) + STACK_SIZE;
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uint64_t *rbp = &new_regs->rbp;
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uint64_t *tmp = rbp;
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// 超出内核栈范围
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if ((uint64_t)*rbp >= old_top || (uint64_t)*rbp < (old_top - STACK_SIZE))
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return 0;
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while (1)
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{
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// 计算delta
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uint64_t delta = old_top - *rbp;
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// 计算新的rbp值
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uint64_t newVal = new_top - delta;
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// 新的值不合法
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if (unlikely((uint64_t)newVal >= new_top || (uint64_t)newVal < (new_top - STACK_SIZE)))
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break;
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// 将新的值写入对应位置
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*rbp = newVal;
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// 跳转栈帧
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rbp = (uint64_t *)*rbp;
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}
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// 设置内核态fork返回到enter_syscall_int()函数内的时候，rsp寄存器的值
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new_regs->rsp = new_top - (old_top - new_regs->rsp);
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return 0;
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}
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/**
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* @brief 拷贝当前进程的线程结构体
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*
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@ -987,26 +1038,45 @@ uint64_t process_copy_thread(uint64_t clone_flags, struct process_control_block
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memset(thd, 0, sizeof(struct thread_struct));
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pcb->thread = thd;
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struct pt_regs *child_regs = NULL;
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// 拷贝栈空间
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struct pt_regs *child_regs = (struct pt_regs *)((uint64_t)pcb + STACK_SIZE - sizeof(struct pt_regs));
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if (pcb->flags & PF_KFORK) // 内核态下的fork
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{
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// 内核态下则拷贝整个内核栈
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uint32_t size = ((uint64_t)current_pcb) + STACK_SIZE - (uint64_t)(current_regs);
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child_regs = (struct pt_regs *)(((uint64_t)pcb) + STACK_SIZE - size);
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memcpy(child_regs, (void *)current_regs, size);
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// 然后重写新的栈中，每个栈帧的rbp值
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process_rewrite_rbp(child_regs, pcb);
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}
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else
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{
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child_regs = (struct pt_regs *)((uint64_t)pcb + STACK_SIZE - sizeof(struct pt_regs));
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memcpy(child_regs, current_regs, sizeof(struct pt_regs));
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child_regs->rsp = stack_start;
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}
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// 设置子进程的返回值为0
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child_regs->rax = 0;
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child_regs->rsp = stack_start;
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if (pcb->flags & PF_KFORK)
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thd->rbp = (uint64_t)(child_regs + 1); // 设置新的内核线程开始执行时的rbp（也就是进入ret_from_system_call时的rbp）
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else
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thd->rbp = (uint64_t)pcb + STACK_SIZE;
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// 设置新的内核线程开始执行的时候的rsp
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thd->rsp = (uint64_t)child_regs;
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thd->fs = current_pcb->thread->fs;
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thd->gs = current_pcb->thread->gs;
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// kdebug("pcb->flags=%ld", pcb->flags);
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// 根据是否为内核线程，设置进程的开始执行的地址
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if (pcb->flags & PF_KTHREAD)
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// 根据是否为内核线程、是否在内核态fork，设置进程的开始执行的地址
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if (pcb->flags & PF_KFORK)
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thd->rip = (uint64_t)ret_from_system_call;
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else if (pcb->flags & PF_KTHREAD && (!(pcb->flags & PF_KFORK)))
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thd->rip = (uint64_t)kernel_thread_func;
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else
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thd->rip = (uint64_t)ret_from_system_call;
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// kdebug("new proc's ret addr = %#018lx\tthd->rip=%#018lx stack_start=%#018lx child_regs->rsp = %#018lx, new_rip=%#018lx)", child_regs->rbx, thd->rip, stack_start, child_regs->rsp, child_regs->rip);
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return 0;
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}
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@ -95,6 +95,7 @@ struct thread_struct
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#define PF_KTHREAD (1UL << 0) // 内核线程
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#define PF_NEED_SCHED (1UL << 1) // 进程需要被调度
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#define PF_VFORK (1UL << 2) // 标志进程是否由于vfork而存在资源共享
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#define PF_KFORK (1UL << 3) // 标志在内核态下调用fork（临时标记，do_fork()结束后会将其复位）
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/**
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* @brief 进程控制块
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@ -86,6 +86,7 @@ long enter_syscall_int(ul syscall_id, ul arg0, ul arg1, ul arg2, ul arg3, ul arg
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: "=a"(err_code)
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: "a"(syscall_id), "m"(arg0), "m"(arg1), "m"(arg2), "m"(arg3), "m"(arg4), "m"(arg5), "m"(arg6), "m"(arg7)
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: "memory", "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15", "rcx", "rdx");
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return err_code;
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}
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@ -426,12 +427,10 @@ uint64_t sys_lseek(struct pt_regs *regs)
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uint64_t sys_fork(struct pt_regs *regs)
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{
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// kdebug("sys_fork");
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return do_fork(regs, 0, regs->rsp, 0);
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}
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uint64_t sys_vfork(struct pt_regs *regs)
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{
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kdebug("sys vfork");
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return do_fork(regs, CLONE_VM | CLONE_FS | CLONE_SIGNAL, regs->rsp, 0);
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}
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