regression: mmap for fd

[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 9d5e1d1bdbe2bc10fab8514bec0fe71f6b915bb7..bbaf59f407655225f86794fd6c0025e3af7c7374 100644 (file)
--- a/lunaix-os/kernel/asm/x86/pfault.c
+++ b/lunaix-os/kernel/asm/x86/pfault.c
@@ -1,5 +1,6 @@
 #include <arch/x86/interrupts.h>
 #include <lunaix/common.h>
+#include <lunaix/lxsignal.h>
 #include <lunaix/mm/mm.h>
 #include <lunaix/mm/pmm.h>
 #include <lunaix/mm/region.h>
@@ -8,6 +9,8 @@
 #include <lunaix/status.h>
 #include <lunaix/syslog.h>
 
+#include <klibc/string.h>
+
 static void
 kprintf(const char* fmt, ...)
 {
@@ -17,6 +20,8 @@ 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);
 
@@ -28,53 +33,116 @@ intr_routine_page_fault(const isr_param* param)
         goto segv_term;
     }
 
-    struct mm_region* hit_region = region_get(__current, ptr);
+    v_mapping mapping;
+    if (!vmm_lookup(ptr, &mapping)) {
+        goto segv_term;
+    }
+
+    if (!SEL_RPL(param->cs)) {
+        // 如果是内核页错误……
+        if (do_kernel(&mapping)) {
+            return;
+        }
+        // 如果不是，那么看看内核是不是需要用户页。
+    }
+
+    struct mm_region* hit_region = region_get(&__current->mm.regions, 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)) {
+    volatile x86_pte_t* pte = &PTE_MOUNTED(PD_REFERENCED, ptr >> 12);
+    if (PG_PRESENTED(*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));
             pmm_free_page(__current->pid, *pte & ~0xFFF);
             *pte = (*pte & 0xFFF) | pa | PG_WRITE;
-            return;
+            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_PRESENTED(*pte)) {
+            cpu_invplg(pte);
+            uintptr_t pa = pmm_alloc_page(__current->pid, 0);
+            if (!pa) {
+                goto oom;
+            }
+
+            *pte = *pte | pa | PG_PRESENT;
+            goto resolved;
+        }
+        // permission denied on anon 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);
+
+    // if mfile is set (Non-anonymous), then it is a mem map
+    if (hit_region->mfile && !PG_PRESENTED(*pte)) {
+        struct v_file* file = hit_region->mfile;
+        u32_t offset =
+          (ptr - hit_region->start) & (PG_SIZE - 1) + hit_region->offset;
         uintptr_t pa = pmm_alloc_page(__current->pid, 0);
-        *pte = *pte | pa | PG_PRESENT;
-        return;
+
+        if (!pa) {
+            goto oom;
+        }
+
+        cpu_invplg(pte);
+        *pte = (*pte & 0xFFF) | pa | PG_PRESENT;
+
+        ptr = ptr & ~(PG_SIZE - 1);
+        memset(ptr, 0, PG_SIZE);
+
+        int errno = file->ops->read_page(file->inode, ptr, PG_SIZE, offset);
+        if (errno < 0) {
+            kprintf(KERROR "fail to read page (%d)\n", errno);
+            goto segv_term;
+        }
+
+        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",
             __current->pid,
             ptr,
             param->cs,
             param->eip);
-    terminate_proc(LXSEGFAULT);
+    __SIGSET(__current->sig_pending, _SIGSEGV);
+    schedule();
     // should not reach
+    while (1)
+        ;
+
+resolved:
+    cpu_invplg(ptr);
+    return;
+}
+
+int
+do_kernel(v_mapping* mapping)
+{
+    uintptr_t addr = mapping->va;
+
+    // TODO
+
+    return 0;
+done:
+    return 1;
 }
\ No newline at end of file