X-Git-Url: https://scm.lunaixsky.com/lunaix-os.git/blobdiff_plain/2e21eb2f39dd80aa166216381d5d402be943686e..a89063b334fdc0b254f0791fca1812354049b86d:/lunaix-os/kernel/process.c

diff --git a/lunaix-os/kernel/process.c b/lunaix-os/kernel/process.c
index de6eaf6..a783efe 100644
--- a/lunaix-os/kernel/process.c
+++ b/lunaix-os/kernel/process.c
@@ -1,89 +1,252 @@
-#include <lunaix/process.h>
-#include <lunaix/mm/vmm.h>
+#include <klibc/string.h>
 #include <lunaix/clock.h>
-#include <lunaix/syslog.h>
 #include <lunaix/common.h>
+#include <lunaix/mm/pmm.h>
+#include <lunaix/mm/region.h>
+#include <lunaix/mm/vmm.h>
+#include <lunaix/process.h>
+#include <lunaix/spike.h>
+#include <lunaix/status.h>
+#include <lunaix/syscall.h>
+#include <lunaix/syslog.h>
 
 LOG_MODULE("PROC")
 
-void* __dup_pagetable(pid_t pid, uintptr_t mount_point) {
+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*) (mount_point | (0x3FF << 12));
+    vmm_set_mapping(PD_REFERENCED, PG_MOUNT_1, ptd_pp, PG_PREM_RW, VMAP_NULL);
+
+    x86_page_table* ptd = PG_MOUNT_1;
+    x86_page_table* pptd = (x86_page_table*)(mount_point | (0x3FF << 12));
+
+    size_t kspace_l1inx = L1_INDEX(KERNEL_MM_BASE);
+
+    for (size_t i = 0; i < PG_MAX_ENTRIES - 1; i++) {
 
-    for (size_t i = 0; i < PG_MAX_ENTRIES - 1; i++)
-    {
         x86_pte_t ptde = pptd->entry[i];
-        if (!ptde || !(ptde & PG_PRESENT)) {
+        // 空或者是未在内存中的L1页表项直接照搬过去。
+        // 内核地址空间直接共享过去。
+        if (!ptde || i >= kspace_l1inx || !(ptde & PG_PRESENT)) {
             ptd->entry[i] = ptde;
             continue;
         }
-        
-        x86_page_table* ppt = (x86_page_table*) (mount_point | (i << 12));
+
+        // 复制L2页表
         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;
-            }
+        vmm_set_mapping(
+          PD_REFERENCED, PG_MOUNT_2, pt_pp, PG_PREM_RW, VMAP_NULL);
 
-            // 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(pid, PG_ENTRY_ADDR(ppte));
-                ppte = ppte & 0xfff | (uintptr_t)ppa;
-            }
-            pt->entry[j] = ppte;
-            // ppte = ppte & ~PG_WRITE;
-            // pt->entry[j] = ppte;
-            // ppt->entry[j] = ppte;
+        x86_page_table* ppt = (x86_page_table*)(mount_point | (i << 12));
+        x86_page_table* pt = PG_MOUNT_2;
+
+        for (size_t j = 0; j < PG_MAX_ENTRIES; j++) {
+            x86_pte_t pte = ppt->entry[j];
+            pmm_ref_page(pid, PG_ENTRY_ADDR(pte));
+            pt->entry[j] = pte;
         }
 
-        ptd->entry[i] = (uintptr_t)pt_pp | PG_PREM_RW;
+        ptd->entry[i] = (uintptr_t)pt_pp | PG_ENTRY_FLAGS(ptde);
     }
-    
+
     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, L2_BASE_VADDR);
+void
+__del_pagetable(pid_t pid, uintptr_t mount_point)
+{
+    x86_page_table* pptd = (x86_page_table*)(mount_point | (0x3FF << 12));
+
+    // only remove user address space
+    for (size_t i = 0; i < L1_INDEX(KERNEL_MM_BASE); i++) {
+        x86_pte_t ptde = pptd->entry[i];
+        if (!ptde || !(ptde & PG_PRESENT)) {
+            continue;
+        }
+
+        x86_page_table* ppt = (x86_page_table*)(mount_point | (i << 12));
+
+        for (size_t j = 0; j < PG_MAX_ENTRIES; j++) {
+            x86_pte_t pte = ppt->entry[j];
+            // free the 4KB data page
+            if ((pte & PG_PRESENT)) {
+                pmm_free_page(pid, PG_ENTRY_ADDR(pte));
+            }
+        }
+        // free the L2 page table
+        pmm_free_page(pid, PG_ENTRY_ADDR(ptde));
+    }
+    // free the L1 directory
+    pmm_free_page(pid, PG_ENTRY_ADDR(pptd->entry[PG_MAX_ENTRIES - 1]));
+}
+
+void*
+vmm_dup_vmspace(pid_t pid)
+{
+    return __dup_pagetable(pid, PD_REFERENCED);
 }
 
-void dup_proc() {
-    pid_t pid = alloc_pid();
+__DEFINE_LXSYSCALL(pid_t, fork)
+{
+    return dup_proc();
+}
 
-    /* 
-        FIXME: Problematic! It should mount the page table of process then copy it.
-        The current implementation copy the CURRENTLY loaded pgt.
-        However, dup_pagetable is designed to copy current loaded pgt.
-        
-    */
+__DEFINE_LXSYSCALL(pid_t, getpid)
+{
+    return __current->pid;
+}
 
-    void* mnt_pt = vmm_mount_pd(__current->page_table);
+__DEFINE_LXSYSCALL(pid_t, getppid)
+{
+    return __current->parent->pid;
+}
 
-    void* pg = __dup_pagetable(pid, mnt_pt);
+__DEFINE_LXSYSCALL(pid_t, getpgid)
+{
+    return __current->pgid;
+}
 
-    vmm_unmount_pd();
+__DEFINE_LXSYSCALL2(int, setpgid, pid_t, pid, pid_t, pgid)
+{
+    struct proc_info* proc = pid ? get_process(pid) : __current;
+
+    if (!proc) {
+        __current->k_status = LXINVL;
+        return -1;
+    }
+
+    pgid = pgid ? pgid : proc->pid;
+
+    struct proc_info* gruppenfuhrer = get_process(pgid);
+
+    if (!gruppenfuhrer || proc->pgid == proc->pid) {
+        __current->k_status = LXINVL;
+        return -1;
+    }
 
-    struct proc_info pcb = (struct proc_info) {
-        .created = clock_systime(),
-        .pid = pid,
-        .mm = __current->mm,
-        .page_table = pg,
-        .intr_ctx = __current->intr_ctx,
-        .parent_created = __current->created
-    };
+    llist_delete(&proc->grp_member);
+    llist_append(&gruppenfuhrer->grp_member, &proc->grp_member);
+
+    proc->pgid = pgid;
+    return 0;
+}
+
+void
+init_proc_user_space(struct proc_info* pcb)
+{
+    vmm_mount_pd(PD_MOUNT_1, pcb->page_table);
+
+    /*---  分配用户栈  ---*/
+
+    // 注册用户栈区域
+    region_add(
+      &pcb->mm.regions, USTACK_END, USTACK_TOP, REGION_RW | REGION_RSHARED);
+
+    // 预留地址空间，具体物理页将由Page Fault Handler按需分配。
+    for (uintptr_t i = PG_ALIGN(USTACK_END); i < USTACK_TOP; i += PG_SIZE) {
+        vmm_set_mapping(PD_MOUNT_1, i, 0, PG_ALLOW_USER | PG_WRITE, VMAP_NULL);
+    }
+
+    // todo: other uspace initialization stuff
+
+    vmm_unmount_pd(PD_MOUNT_1);
+}
+
+void
+__mark_region(uintptr_t start_vpn, uintptr_t end_vpn, int attr)
+{
+    for (size_t i = start_vpn; i <= end_vpn; i++) {
+        x86_pte_t* curproc = &PTE_MOUNTED(PD_REFERENCED, i);
+        x86_pte_t* newproc = &PTE_MOUNTED(PD_MOUNT_1, i);
+        cpu_invplg(newproc);
+
+        if ((attr & REGION_MODE_MASK) == 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。
+            cpu_invplg(curproc);
+            cpu_invplg(i << 12);
+            *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;
+        }
+    }
+}
+
+pid_t
+dup_proc()
+{
+    struct proc_info* pcb = alloc_process();
+    pcb->mm.u_heap = __current->mm.u_heap;
+    pcb->intr_ctx = __current->intr_ctx;
+    pcb->parent = __current;
+
+    region_copy(&__current->mm.regions, &pcb->mm.regions);
+
+    setup_proc_mem(pcb, PD_REFERENCED);
+
+    // 根据 mm_region 进一步配置页表
+
+    struct mm_region *pos, *n;
+    llist_for_each(pos, n, &pcb->mm.regions.head, head)
+    {
+        // 如果写共享，则不作处理。
+        if ((pos->attr & REGION_WSHARED)) {
+            continue;
+        }
+
+        uintptr_t start_vpn = pos->start >> 12;
+        uintptr_t end_vpn = pos->end >> 12;
+        __mark_region(start_vpn, end_vpn, pos->attr);
+    }
+
+    vmm_unmount_pd(PD_MOUNT_1);
 
     // 正如同fork，返回两次。
-    pcb.intr_ctx.registers.eax = 0;
-    __current->intr_ctx.registers.eax = pid;
+    pcb->intr_ctx.registers.eax = 0;
+
+    commit_process(pcb);
+
+    return pcb->pid;
+}
+
+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_1, 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++) {
+        volatile x86_pte_t* ppte = &PTE_MOUNTED(PD_MOUNT_1, i);
+
+        /*
+            This is a fucking nightmare, the TLB caching keep the rewrite to PTE
+           from updating. Even the Nightmare Moon the Evil is far less nasty
+           than this. It took me hours of debugging to figure this out.
+
+            In the name of Celestia our glorious goddess, I will fucking HATE
+           the TLB for the rest of my LIFE!
+        */
+        cpu_invplg(ppte);
+
+        x86_pte_t p = *ppte;
+        void* ppa = vmm_dup_page(pid, PG_ENTRY_ADDR(p));
+        pmm_free_page(pid, PG_ENTRY_ADDR(p));
+        *ppte = (p & 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.
 
-    push_process(&pcb);
-    
+    // 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