refactor: full rewrite of signal feature

[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 c5ec07f5f37bdf9dd61bb9975d68c1b1c2f303b6..f527e12c3dcc0f81c292c3761c78c125943faa80 100644 (file)
--- a/lunaix-os/kernel/asm/x86/pfault.c
+++ b/lunaix-os/kernel/asm/x86/pfault.c
@@ -1,21 +1,172 @@
 #include <arch/x86/interrupts.h>
 #include <arch/x86/interrupts.h>

+#include <lunaix/common.h>
+#include <lunaix/mm/mm.h>

 #include <lunaix/mm/pmm.h>
 #include <lunaix/mm/pmm.h>

+#include <lunaix/mm/region.h>

 #include <lunaix/mm/vmm.h>
 #include <lunaix/mm/vmm.h>

-#include <lunaix/common.h>
+#include <lunaix/sched.h>
+#include <lunaix/signal.h>
+#include <lunaix/status.h>
+#include <lunaix/syslog.h>
+
+#include <klibc/string.h>
+
+static u32_t
+get_ptattr(struct mm_region* vmr)
+{
+    u32_t vmr_attr = vmr->attr;
+    u32_t ptattr = PG_PRESENT | PG_ALLOW_USER;
+
+    if ((vmr_attr & PROT_WRITE)) {
+        ptattr |= PG_WRITE;
+    }
+
+    return ptattr & 0xfff;
+}
+
+static void
+kprintf(const char* fmt, ...)
+{
+    va_list args;
+    va_start(args, fmt);
+    __kprintf("PFAULT", fmt, args);
+    va_end(args);
+}
+
+#define COW_MASK (REGION_RSHARED | REGION_READ | REGION_WRITE)

 
 

-extern void __print_panic_msg(const char* msg, const isr_param* param);
+extern void
+__print_panic_msg(const char* msg, const isr_param* param);

 
 void
 
 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;
+    uint32_t errcode = param->execp->err_code;
+    ptr_t ptr = cpu_rcr2();
+    if (!ptr) {
+        goto segv_term;
+    }
+
+    v_mapping mapping;
+    if (!vmm_lookup(ptr, &mapping)) {
+        goto segv_term;
+    }
+
+    if (!SEL_RPL(param->execp->cs)) {
+        // TODO if kernel pfault
+    }
+
+    vm_regions_t* vmr = (vm_regions_t*)&__current->mm.regions;
+    struct mm_region* hit_region = region_get(vmr, ptr);
+
+    if (!hit_region) {
+        // 当你凝视深渊时……
+        goto segv_term;
+    }
+
+    volatile x86_pte_t* pte = &PTE_MOUNTED(VMS_SELF, ptr >> 12);
+    if (PG_IS_PRESENT(*pte)) {
+        if (((errcode ^ mapping.flags) & PG_ALLOW_USER)) {
+            // invalid access
+            kprintf(KDEBUG "invalid user access. (%p->%p, attr:0x%x)\n",
+                    mapping.va,
+                    mapping.pa,
+                    mapping.flags);
+            goto segv_term;
+        }
+        if ((hit_region->attr & COW_MASK) == COW_MASK) {
+            // normal page fault, do COW
+            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 & ~PG_DIRTY) | pa | PG_WRITE;
+
+            goto resolved;
+        }
+        // impossible cases or accessing privileged page
+        goto segv_term;
+    }
+
+    // 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 | get_ptattr(hit_region);
+            memset((void*)PG_ALIGN(ptr), 0, PG_SIZE);
+            goto resolved;
+        }
+        // permission denied on anon page (e.g., write on readonly page)
+        goto segv_term;

     }
 
     }
 

-    __print_panic_msg("Page fault", param);
+    // 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 | get_ptattr(hit_region);
+
+        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, 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,e=0x%x)\n",
+            __current->pid,
+            ptr,
+            param->execp->cs,
+            param->execp->eip,
+            param->execp->err_code);
+
+    sigset_add(__current->sigctx.sig_pending, _SIGSEGV);
+
+    schedule();
+    // should not reach
+    while (1)
+        ;

 
 

-done:
-    while(1);
+resolved:
+    cpu_invplg(ptr);
+    return;

 }
\ No newline at end of file
 }
\ No newline at end of file