feat: No more kernel page table switching upon interrupt.

[lunaix-os.git] / lunaix-os / kernel / process.c

diff --git a/lunaix-os/kernel/process.c b/lunaix-os/kernel/process.c
index 29cff62c78f16805077a2bbe277ffbc7b2125440..5112ae19e04a7e78ddf2cc36587e5684799ff5a0 100644 (file)
--- a/lunaix-os/kernel/process.c
+++ b/lunaix-os/kernel/process.c
@@ -6,6 +6,7 @@
 #include <lunaix/common.h>
 #include <lunaix/syscall.h>
 #include <lunaix/spike.h>
 #include <lunaix/common.h>
 #include <lunaix/syscall.h>
 #include <lunaix/spike.h>

+#include <klibc/string.h>

 
 LOG_MODULE("PROC")
 
 
 LOG_MODULE("PROC")
 


@@ -29,7 +30,7 @@ void* __dup_pagetable(pid_t pid, uintptr_t mount_point) {
         for (size_t j = 0; j < PG_MAX_ENTRIES; j++)
         {
             x86_pte_t pte = ppt->entry[j];
         for (size_t j = 0; j < PG_MAX_ENTRIES; j++)
         {
             x86_pte_t pte = ppt->entry[j];

-            pmm_ref_page(pid, pte & ~0xfff);
+            pmm_ref_page(pid, PG_ENTRY_ADDR(pte));

             pt->entry[j] = pte;
         }
 
             pt->entry[j] = pte;
         }
 


@@ -41,12 +42,39 @@ void* __dup_pagetable(pid_t pid, uintptr_t mount_point) {
     return ptd_pp;
 }
 
     return ptd_pp;
 }
 

+void __del_pagetable(pid_t pid, uintptr_t mount_point) {
+    x86_page_table* pptd = (x86_page_table*) (mount_point | (0x3FF << 12));
+
+    for (size_t i = 0; i < PG_MAX_ENTRIES - 1; 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* dup_pagetable(pid_t pid) {
     return __dup_pagetable(pid, PD_REFERENCED);
 }
 
 void* dup_pagetable(pid_t pid) {
     return __dup_pagetable(pid, PD_REFERENCED);
 }
 

-__DEFINE_LXSYSCALL(void, fork) {
-    dup_proc();
+__DEFINE_LXSYSCALL(pid_t, fork) {
+    return dup_proc();

 }
 
 __DEFINE_LXSYSCALL(pid_t, getpid) {
 }
 
 __DEFINE_LXSYSCALL(pid_t, getpid) {


@@ -57,57 +85,71 @@ __DEFINE_LXSYSCALL(pid_t, getppid) {
     return __current->parent->pid;
 }
 
     return __current->parent->pid;
 }
 

-void dup_proc() {
-    pid_t pid = alloc_pid();
+void init_proc(struct proc_info *pcb) {
+    memset(pcb, 0, sizeof(*pcb));
+
+    pcb->pid = alloc_pid();
+    pcb->created = clock_systime();
+    pcb->state = PROC_CREATED;
+}

 
 

-    struct proc_info pcb = (struct proc_info) {
-        .created = clock_systime(),
-        .pid = pid,
-        .mm = __current->mm,
-        .intr_ctx = __current->intr_ctx,
-        .parent = __current
-    };
+pid_t dup_proc() {
+    struct proc_info pcb;
+    init_proc(&pcb);
+    pcb.mm = __current->mm;
+    pcb.intr_ctx = __current->intr_ctx;
+    pcb.parent = __current;

 
 

+#ifdef USE_KERNEL_PG

     setup_proc_mem(&pcb, PD_MOUNT_1);    //挂载点#1是当前进程的页表
     setup_proc_mem(&pcb, PD_MOUNT_1);    //挂载点#1是当前进程的页表

+#else
+    setup_proc_mem(&pcb, PD_REFERENCED);
+#endif

 
     // 根据 mm_region 进一步配置页表
 
     // 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;
-            }
+    if (!__current->mm.regions) {
+        goto not_copy;
+    }
+    
+    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;
-                }
+        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 = &PTE_MOUNTED(PD_MOUNT_1, i);
+            x86_pte_t *newproc = &PTE_MOUNTED(PD_MOUNT_2, i);
+            cpu_invplg(curproc);
+            cpu_invplg(newproc);
+
+            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;

             }
         }
     }
     
             }
         }
     }
     

+not_copy:

     vmm_unmount_pd(PD_MOUNT_2);
 
     // 正如同fork，返回两次。
     pcb.intr_ctx.registers.eax = 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);
 
     push_process(&pcb);

+
+    return pcb.pid;

 }
 
 extern void __kernel_end;
 }
 
 extern void __kernel_end;


@@ -122,9 +164,20 @@ void setup_proc_mem(struct proc_info* proc, uintptr_t usedMnt) {
     // copy the kernel stack
     for (size_t i = KSTACK_START >> 12; i <= KSTACK_TOP >> 12; i++)
     {
     // 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;
+        volatile x86_pte_t *ppte = &PTE_MOUNTED(PD_MOUNT_2, 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));
+        *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
     }
 
     // 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