feat: basic elf32 loader (only LOAD segment is supported)

[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 64986190bddf58c85cc5c2cc3c792267d6730151..2388f38c2db7f8017859b6be8fd3987ed80a6c61 100644 (file)
--- a/lunaix-os/kernel/asm/x86/pfault.c
+++ b/lunaix-os/kernel/asm/x86/pfault.c
@@ -1,14 +1,16 @@
 #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>
 #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, ...)
 {
@@ -51,43 +53,40 @@ intr_routine_page_fault(const isr_param* param)
         goto segv_term;
     }
 
-    volatile x86_pte_t* pte = &PTE_MOUNTED(PD_REFERENCED, ptr >> 12);
-    if ((*pte & PG_PRESENT)) {
+    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));
             pmm_free_page(__current->pid, *pte & ~0xFFF);
-            *pte = (*pte & 0xFFF) | pa | PG_WRITE;
+            *pte = (*pte & 0xFFF & ~PG_DIRTY) | pa | PG_WRITE;
             goto resolved;
         }
         // impossible cases or accessing privileged page
         goto segv_term;
     }
 
-    // if (!(*pte)) {
-    //     // Invalid location
-    //     goto segv_term;
-    // }
-
-    uintptr_t loc = *pte & ~0xfff;
-
-    // a writable page, not present, not cached, pte attr is not null
+    // an anonymous page and not present
     //   -> 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);
-        if (!pa) {
-            goto oom;
-        }
+    if ((hit_region->attr & REGION_ANON)) {
+        if (!PG_IS_PRESENT(*pte)) {
+            cpu_invplg(pte);
+            uintptr_t pa = pmm_alloc_page(__current->pid, 0);
+            if (!pa) {
+                goto oom;
+            }
 
-        *pte = *pte | pa | PG_PRESENT;
-        goto resolved;
+            *pte = *pte | pa | PG_PRESENT;
+            goto resolved;
+        }
+        // permission denied on anon page (e.g., write on readonly page)
+        goto segv_term;
     }
 
-    // if mfile is set, then it is a mem map
-    if (hit_region->mfile) {
+    // 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;
         u32_t offset =
           (ptr - hit_region->start) & (PG_SIZE - 1) + hit_region->offset;
@@ -98,17 +97,29 @@ intr_routine_page_fault(const isr_param* param)
         }
 
         cpu_invplg(pte);
-        *pte = *pte | pa | PG_PRESENT;
-        int errno = file->ops->read_page(
-          file->inode, ptr & (PG_SIZE - 1), PG_SIZE, offset);
+        *pte = (*pte & 0xFFF) | pa | PG_PRESENT;
+
+        ptr = PG_ALIGN(ptr);
+        memset(ptr, 0, PG_SIZE);
+
+        int errno = 0;
+        if (hit_region->init_page) {
+            errno = hit_region->init_page(hit_region, ptr, offset);
+        } else {
+            errno = file->ops->read_page(file->inode, ptr, PG_SIZE, offset);
+        }
+
         if (errno < 0) {
-            kprintf(KERROR "fail to read page (%d)\n", errno);
+            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)
         ;