refactor: rewrite kernel's make script

[lunaix-os.git] / lunaix-os / kernel / asm / x86 / pfault.c

diff --git a/lunaix-os/kernel/asm/x86/pfault.c b/lunaix-os/kernel/asm/x86/pfault.c
index 34589cbe6685fc60b49aeb65fcf95819cef4e4cf..70d5e560da7a145ca1b154f9e52cafd749e38d26 100644 (file)
--- a/lunaix-os/kernel/asm/x86/pfault.c
+++ b/lunaix-os/kernel/asm/x86/pfault.c
@@ -5,9 +5,12 @@
 #include <lunaix/mm/region.h>
 #include <lunaix/mm/vmm.h>
 #include <lunaix/sched.h>
+#include <lunaix/signal.h>
 #include <lunaix/status.h>
 #include <lunaix/syslog.h>
 
+#include <klibc/string.h>
+
 static void
 kprintf(const char* fmt, ...)
 {
@@ -17,13 +20,16 @@ kprintf(const char* fmt, ...)
     va_end(args);
 }
 
+#define COW_MASK (REGION_RSHARED | REGION_READ | REGION_WRITE)
+
 extern void
 __print_panic_msg(const char* msg, const isr_param* param);
 
 void
 intr_routine_page_fault(const isr_param* param)
 {
-    uintptr_t ptr = cpu_rcr2();
+    uint32_t errcode = param->execp->err_code;
+    ptr_t ptr = cpu_rcr2();
     if (!ptr) {
         goto segv_term;
     }
@@ -33,79 +39,118 @@ intr_routine_page_fault(const isr_param* param)
         goto segv_term;
     }
 
-    if (!SEL_RPL(param->cs)) {
-        // 如果是内核页错误……
-        if (do_kernel(&mapping)) {
-            return;
-        }
-        goto segv_term;
+    if (!SEL_RPL(param->execp->cs)) {
+        // TODO if kernel pfault
     }
 
-    struct mm_region* hit_region = region_get(&__current->mm.regions, ptr);
+    vm_regions_t* vmr = (vm_regions_t*)&__current->mm.regions;
+    struct mm_region* hit_region = region_get(vmr, ptr);
 
     if (!hit_region) {
-        // Into the void...
+        // 当你凝视深渊时……
         goto segv_term;
     }
 
-    x86_pte_t* pte = PTE_MOUNTED(PD_REFERENCED, ptr >> 12);
-    if (*pte & PG_PRESENT) {
-        if ((hit_region->attr & REGION_PERM_MASK) ==
-            (REGION_RSHARED | REGION_READ)) {
+    if ((errcode & PG_ALLOW_USER)) {
+        // invalid access
+        goto segv_term;
+    }
+
+    volatile x86_pte_t* pte = &PTE_MOUNTED(VMS_SELF, ptr >> 12);
+    if (PG_IS_PRESENT(*pte)) {
+        if ((hit_region->attr & COW_MASK) == COW_MASK) {
             // normal page fault, do COW
-            cpu_invplg(pte);
-            uintptr_t pa =
-              (uintptr_t)vmm_dup_page(__current->pid, PG_ENTRY_ADDR(*pte));
+            cpu_invplg((ptr_t)pte);
+
+            ptr_t pa = (ptr_t)vmm_dup_page(__current->pid, PG_ENTRY_ADDR(*pte));
+
             pmm_free_page(__current->pid, *pte & ~0xFFF);
-            *pte = (*pte & 0xFFF) | pa | PG_WRITE;
-            return;
+            *pte = (*pte & 0xFFF & ~PG_DIRTY) | pa | PG_WRITE;
+
+            goto resolved;
         }
         // impossible cases or accessing privileged page
         goto segv_term;
     }
 
-    if (!(*pte)) {
-        // Invalid location
+    // an anonymous page and not present
+    //   -> a new page need to be alloc
+    if ((hit_region->attr & REGION_ANON)) {
+        if (!PG_IS_PRESENT(*pte)) {
+            cpu_invplg((ptr_t)pte);
+
+            ptr_t pa = pmm_alloc_page(__current->pid, 0);
+            if (!pa) {
+                goto oom;
+            }
+
+            *pte = *pte | pa | PG_PRESENT | PG_ALLOW_USER;
+            memset((void*)PG_ALIGN(ptr), 0, PG_SIZE);
+            goto resolved;
+        }
+        // permission denied on anon page (e.g., write on readonly page)
         goto segv_term;
     }
-    uintptr_t loc = *pte & ~0xfff;
-    // a writable page, not present, pte attr is not null
-    //   and no indication of cached page -> a new page need to be alloc
-    if ((hit_region->attr & REGION_WRITE) && (*pte & 0xfff) && !loc) {
-        cpu_invplg(pte);
-        uintptr_t pa = pmm_alloc_page(__current->pid, 0);
-        *pte = *pte | pa | PG_PRESENT;
-        return;
+
+    // if mfile is set (Non-anonymous), then it is a mem map
+    if (hit_region->mfile && !PG_IS_PRESENT(*pte)) {
+        struct v_file* file = hit_region->mfile;
+
+        ptr = PG_ALIGN(ptr);
+
+        u32_t mseg_off = (ptr - hit_region->start);
+        u32_t mfile_off = mseg_off + hit_region->foff;
+        ptr_t pa = pmm_alloc_page(__current->pid, 0);
+
+        if (!pa) {
+            goto oom;
+        }
+
+        cpu_invplg((ptr_t)pte);
+        *pte = (*pte & 0xFFF) | pa | PG_PRESENT | PG_ALLOW_USER;
+
+        memset((void*)ptr, 0, PG_SIZE);
+
+        int errno = 0;
+        if (mseg_off < hit_region->flen) {
+            errno =
+              file->ops->read_page(file->inode, (void*)ptr, PG_SIZE, mfile_off);
+        }
+
+        if (errno < 0) {
+            kprintf(KERROR "fail to populate page (%d)\n", errno);
+            goto segv_term;
+        }
+
+        *pte &= ~PG_DIRTY;
+
+        goto resolved;
     }
-    // page not present, bring it from disk or somewhere else
+
+    // page not present, might be a chance to introduce swap file?
     __print_panic_msg("WIP page fault route", param);
     while (1)
         ;
 
+oom:
+    kprintf(KERROR "out of memory\n");
+
 segv_term:
-    kprintf(KERROR "(pid: %d) Segmentation fault on %p (%p:%p)\n",
+    kprintf(KERROR "(pid: %d) Segmentation fault on %p (%p:%p,e=0x%x)\n",
             __current->pid,
             ptr,
-            param->cs,
-            param->eip);
-    terminate_proc(LXSEGFAULT);
-    // should not reach
-}
+            param->execp->cs,
+            param->execp->eip,
+            param->execp->err_code);
 
-int
-do_kernel(v_mapping* mapping)
-{
-    uintptr_t addr = mapping->va;
-    if (addr >= KHEAP_START && addr < PROC_START) {
-        // This is kernel heap page
-        uintptr_t pa = pmm_alloc_page(KERNEL_PID, 0);
-        *mapping->pte = (*mapping->pte & 0xfff) | pa | PG_PRESENT;
-        cpu_invplg(mapping->pte);
-        cpu_invplg(addr);
-        goto done;
-    }
+    __SIGSET(__current->sig_pending, _SIGSEGV);
+
+    schedule();
+    // should not reach
+    while (1)
+        ;
 
-    return 0;
-done:
-    return 1;
+resolved:
+    cpu_invplg(ptr);
+    return;
 }
\ No newline at end of file