#include <lunaix/process.h>
#include <lunaix/mm/vmm.h>
+#include <lunaix/mm/region.h>
#include <lunaix/clock.h>
#include <lunaix/syslog.h>
#include <lunaix/common.h>
+#include <lunaix/syscall.h>
+#include <lunaix/spike.h>
LOG_MODULE("PROC")
-void dup_proc() {
- pid_t pid = alloc_pid();
-
+void* __dup_pagetable(pid_t pid, uintptr_t mount_point) {
void* ptd_pp = pmm_alloc_page(pid, PP_FGPERSIST);
x86_page_table* ptd = vmm_fmap_page(pid, PG_MOUNT_1, ptd_pp, PG_PREM_RW);
- x86_page_table* pptd = (x86_page_table*) L1_BASE_VADDR;
+ x86_page_table* pptd = (x86_page_table*) (mount_point | (0x3FF << 12));
for (size_t i = 0; i < PG_MAX_ENTRIES - 1; i++)
{
continue;
}
- x86_page_table* ppt = (x86_page_table*) L2_VADDR(i);
+ x86_page_table* ppt = (x86_page_table*) (mount_point | (i << 12));
void* pt_pp = pmm_alloc_page(pid, PP_FGPERSIST);
x86_page_table* pt = vmm_fmap_page(pid, PG_MOUNT_2, pt_pp, PG_PREM_RW);
for (size_t j = 0; j < PG_MAX_ENTRIES; j++)
{
- uintptr_t va = ((i << 10) | j) << 12;
- x86_pte_t ppte = ppt->entry[j];
- if (!ppte || !(ppte & PG_PRESENT)) {
- pt->entry[j] = ppte;
- continue;
- }
-
- // FIXME: 根据 mm_region 将读共享的页（如堆）标为只读，而私有的页（如栈），则复制；而写共享的页则无需更改flags
- if (va >= KSTACK_START) {
- void* ppa = vmm_dup_page(va);
- ppte = ppte & 0xfff | (uintptr_t)ppa;
- }
- pt->entry[j] = ppte;
- // ppte = ppte & ~PG_WRITE;
- // pt->entry[j] = ppte;
- // ppt->entry[j] = ppte;
+ x86_pte_t pte = ppt->entry[j];
+ pmm_ref_page(pid, pte & ~0xfff);
+ pt->entry[j] = pte;
}
ptd->entry[i] = (uintptr_t)pt_pp | PG_PREM_RW;
ptd->entry[PG_MAX_ENTRIES - 1] = NEW_L1_ENTRY(T_SELF_REF_PERM, ptd_pp);
+ return ptd_pp;
+}
+
+void* dup_pagetable(pid_t pid) {
+ return __dup_pagetable(pid, PD_REFERENCED);
+}
+
+__DEFINE_LXSYSCALL(void, fork) {
+ dup_proc();
+}
+
+__DEFINE_LXSYSCALL(pid_t, getpid) {
+ return __current->pid;
+}
+
+__DEFINE_LXSYSCALL(pid_t, getppid) {
+ return __current->parent->pid;
+}
+
+void dup_proc() {
+ pid_t pid = alloc_pid();
+
struct proc_info pcb = (struct proc_info) {
.created = clock_systime(),
.pid = pid,
.mm = __current->mm,
- .page_table = ptd_pp,
.intr_ctx = __current->intr_ctx,
- .parent_created = __current->created
+ .parent = __current
};
- // 正如同fork一样，返回两次。
+ setup_proc_mem(&pcb, PD_MOUNT_1); //挂载点#1是当前进程的页表
+
+ // 根据 mm_region 进一步配置页表
+ if (__current->mm.regions) {
+ struct mm_region *pos, *n;
+ llist_for_each(pos, n, &__current->mm.regions->head, head) {
+ region_add(&pcb, pos->start, pos->end, pos->attr);
+
+ // 如果写共享，则不作处理。
+ if ((pos->attr & REGION_WSHARED)) {
+ continue;
+ }
+
+ uintptr_t start_vpn = PG_ALIGN(pos->start) >> 12;
+ uintptr_t end_vpn = PG_ALIGN(pos->end) >> 12;
+ for (size_t i = start_vpn; i < end_vpn; i++)
+ {
+ x86_pte_t *curproc = &((x86_page_table*)(PD_MOUNT_1 | ((i & 0xffc00) << 2)))->entry[i & 0x3ff];
+ x86_pte_t *newproc = &((x86_page_table*)(PD_MOUNT_2 | ((i & 0xffc00) << 2)))->entry[i & 0x3ff];
+
+ if (pos->attr == REGION_RSHARED) {
+ // 如果读共享，则将两者的都标注为只读，那么任何写入都将会应用COW策略。
+ *curproc = *curproc & ~PG_WRITE;
+ *newproc = *newproc & ~PG_WRITE;
+ }
+ else {
+ // 如果是私有页，则将该页从新进程中移除。
+ *newproc = 0;
+ }
+ }
+ }
+ }
+
+ vmm_unmount_pd(PD_MOUNT_2);
+
+ // 正如同fork，返回两次。
pcb.intr_ctx.registers.eax = 0;
__current->intr_ctx.registers.eax = pid;
push_process(&pcb);
+}
+
+extern void __kernel_end;
+
+void setup_proc_mem(struct proc_info* proc, uintptr_t usedMnt) {
+ // copy the entire kernel page table
+ pid_t pid = proc->pid;
+ void* pt_copy = __dup_pagetable(pid, usedMnt);
+
+ vmm_mount_pd(PD_MOUNT_2, pt_copy); // 将新进程的页表挂载到挂载点#2
+
+ // copy the kernel stack
+ for (size_t i = KSTACK_START >> 12; i <= KSTACK_TOP >> 12; i++)
+ {
+ x86_pte_t *ppte = &((x86_page_table*)(PD_MOUNT_2 | ((i & 0xffc00) << 2)))->entry[i & 0x3ff];
+ void* ppa = vmm_dup_page(pid, PG_ENTRY_ADDR(*ppte));
+ *ppte = (*ppte & 0xfff) | (uintptr_t)ppa;
+ }
+
+ // 我们不需要分配内核的区域，因为所有的内核代码和数据段只能通过系统调用来访问，任何非法的访问
+ // 都会导致eip落在区域外面，从而segmentation fault.
+ // 定义用户栈区域，但是不分配实际的物理页。我们会在Page fault handler里面实现动态分配物理页的逻辑。（虚拟内存的好处！）
+ // FIXME: 这里应该放到spawn_proc里面。
+ // region_add(proc, USTACK_END, USTACK_SIZE, REGION_PRIVATE | REGION_RW);
+
+ // 至于其他的区域我们暂时没有办法知道，因为那需要知道用户程序的信息。我们留到之后在处理。
+
+ proc->page_table = pt_copy;
}
\ No newline at end of file
git://scm.lunaixsky.com / lunaix-os.git / blobdiff