X-Git-Url: https://scm.lunaixsky.com/lunaix-os.git/blobdiff_plain/48b4a227035048fdebcd32532deb7a857c6199ac..db4d7d52fa00cc2fd3f25d971f57b73406d816ba:/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 c5ec07f..6df3182 100644
--- a/lunaix-os/kernel/asm/x86/pfault.c
+++ b/lunaix-os/kernel/asm/x86/pfault.c
@@ -1,21 +1,123 @@
 #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/common.h>
+#include <lunaix/sched.h>
+#include <lunaix/status.h>
+#include <lunaix/syslog.h>
+
+static void
+kprintf(const char* fmt, ...)
+{
+    va_list args;
+    va_start(args, fmt);
+    __kprintf("PFAULT", fmt, args);
+    va_end(args);
+}
 
-extern void __print_panic_msg(const char* msg, const isr_param* param);
+#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) 
+intr_routine_page_fault(const isr_param* param)
 {
-    void* pg_fault_ptr = cpu_rcr2();
-    if (!pg_fault_ptr) {
-        __print_panic_msg("Null pointer reference", param);
-        goto done;
+    uintptr_t ptr = cpu_rcr2();
+    if (!ptr) {
+        goto segv_term;
+    }
+
+    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) {
+        // 当你凝视深渊时……
+        goto segv_term;
     }
 
-    __print_panic_msg("Page fault", param);
+    volatile x86_pte_t* pte = &PTE_MOUNTED(PD_REFERENCED, ptr >> 12);
+    if ((*pte & PG_PRESENT)) {
+        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;
+            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
+    //   -> 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;
+        goto resolved;
+    }
+
+    // page not present, bring it from disk or somewhere else
+    __print_panic_msg("WIP page fault route", param);
+    while (1)
+        ;
+
+segv_term:
+    kprintf(KERROR "(pid: %d) Segmentation fault on %p (%p:%p)\n",
+            __current->pid,
+            ptr,
+            param->cs,
+            param->eip);
+    __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;
+    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;
+    }
 
+    return 0;
 done:
-    while(1);
+    return 1;
 }
\ No newline at end of file