patch-2.1.16 linux/arch/ppc/mm/fault.c

• Lines: 294
• Date: Wed Dec 18 10:49:52 1996
• Orig file: v2.1.15/linux/arch/ppc/mm/fault.c
• Orig date: Mon Jul 8 11:27:43 1996

diff -u --recursive --new-file v2.1.15/linux/arch/ppc/mm/fault.c linux/arch/ppc/mm/fault.c
@@ -3,6 +3,7 @@
  *
  *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
  *  Ported to PPC by Gary Thomas
+ *  Modified by Cort Dougan (cort@cs.nmt.edu) 
  */
 
 #include <linux/config.h>
@@ -22,164 +23,71 @@
 
 extern void die_if_kernel(char *, struct pt_regs *, long);
 extern void do_page_fault(struct pt_regs *, unsigned long, unsigned long);
+void new_page_fault(unsigned long address, unsigned long code, unsigned long text,
+		    struct pt_regs *regs);
+
 
 #undef SHOW_FAULTS
 #undef NOISY_INSTRFAULT
 #undef NOISY_DATAFAULT
 
+unsigned int probingmem = 0;
 #define NEWMM 1
 
-void
-DataAccessException(struct pt_regs *regs)
+void new_page_fault(unsigned long address, unsigned long ppc_code,
+		    unsigned long text, struct pt_regs *regs)
 {
-  pgd_t *dir;
-  pmd_t *pmd;
-  pte_t *pte;
-  int tries, mode = 0;
-  
-#ifdef NOISY_DATAFAULT
-  printk("Data fault on %x\n",regs->dar);
-#endif
-  
-  if (user_mode(regs)) mode |= 0x04;
-  if (regs->dsisr & 0x02000000) mode |= 0x02;  /* Load/store */
-  if (regs->dsisr & 0x08000000) mode |= 0x01;  /* Protection violation */
-  if (mode & 0x01)
-  {
-#ifdef NOISY_DATAFAULT
-    printk("Write Protect fault\n ");
-#endif
-    do_page_fault(regs, regs->dar, mode);
-#ifdef NOISY_DATAFAULT    
-    printk("Write Protect fault handled\n");
-#endif
-    return;
-  }
-
-    
-  for (tries = 0;  tries < 1;  tries++)
-  {
-    dir = pgd_offset(current->mm, regs->dar & PAGE_MASK);
-    if (dir)
-    {
-      pmd = pmd_offset(dir, regs->dar & PAGE_MASK);
-      if (pmd && pmd_present(*pmd))
-      {
-	pte = pte_offset(pmd, regs->dar & PAGE_MASK);
-	if (pte && pte_present(*pte))
-	{
-#if NOISY_DATAFAULT
-	  printk("Page mapped - PTE: %x[%x]\n", pte, *(long *)pte);
-#endif
-	  MMU_hash_page(&current->tss, regs->dar & PAGE_MASK, pte);
-	  /*MMU_hash_page2(current->mm, regs->dar & PAGE_MASK, pte);*/
-	  return;
-	}
-      }
-    } else
-    {
-#if NOISY_DATAFAULT
-      printk("No PGD\n");      
-#endif 
-    }
-    do_page_fault(regs, regs->dar, mode);
-  }
-}
+  struct vm_area_struct * vma;
+  struct mm_struct *mm = current->mm;
 
-void
-InstructionAccessException(struct pt_regs *regs)
-{
+  int intel_code = 0;
   pgd_t *dir;
   pmd_t *pmd;
   pte_t *pte;
-  int tries, mode = 0;
   
-#if NOISY_INSTRFAULT
-  printk("Instr fault on %x\n",regs->dar);
-#endif
-
-#ifdef NEWMM
-  if (!user_mode(regs))
-  {
-    
-    panic("InstructionAcessException in kernel mode. PC %x addr %x",
-	  regs->nip, regs->dar);
+  /*
+   *	bit 0 == 0 means no page found, 1 means protection fault
+   *	bit 1 == 0 means read, 1 means write
+   *	bit 2 == 0 means kernel, 1 means user-mode
+   */
+  if (user_mode(regs)) intel_code |= 0x04;
+  if (!text && (ppc_code & 0x02000000)) intel_code |= 0x02;  /* Load/store */
+  if (!text && (ppc_code & 0x08000000))
+  {
+    intel_code |= 0x01;  /* prot viol */
+    goto do_page;
   }
-#endif
-  if (user_mode(regs)) mode |= 0x04;
-  if (regs->dsisr & 0x02000000) mode |= 0x02;  /* Load/store */
-  if (regs->dsisr & 0x08000000) mode |= 0x01;  /* Protection violation */
   
-  if (mode & 0x01)
-  {
-    do_page_fault(regs, regs->dar, mode); 
-    return;
-  }
-  for (tries = 0;  tries < 1;  tries++)
+  dir = pgd_offset(mm, address & PAGE_MASK);
+  if (dir)
   {
-    dir = pgd_offset(current->mm, regs->dar & PAGE_MASK);
-    if (dir)
+    pmd = pmd_offset(dir, address & PAGE_MASK);
+    if (pmd && pmd_present(*pmd))
     {
-      pmd = pmd_offset(dir, regs->dar & PAGE_MASK); 
-      if (pmd && pmd_present(*pmd))
+      pte = pte_offset(pmd, address & PAGE_MASK);
+      if (pte && pte_present(*pte))
       {
- 	pte = pte_offset(pmd, regs->dar & PAGE_MASK); 
-	if (pte && pte_present(*pte))
-	  {
-	    
-	    MMU_hash_page(&current->tss, regs->dar & PAGE_MASK, pte); 
-	    /*	  MMU_hash_page2(current->mm, regs->dar & PAGE_MASK, pte);*/
-	    return;
-	  }
+	MMU_hash_page(&current->tss, address & PAGE_MASK, pte);
+	return;
       }
-    } else
-      {
-      }
-    do_page_fault(regs, regs->dar, mode);
+    }
   }
-}
-
-
-/*
- * This routine handles page faults.  It determines the address,
- * and the problem, and then passes it off to one of the appropriate
- * routines.
- *
- * The error_code parameter just the same as in the i386 version:
- *
- *	bit 0 == 0 means no page found, 1 means protection fault
- *	bit 1 == 0 means read, 1 means write
- *	bit 2 == 0 means kernel, 1 means user-mode
- */
-void do_page_fault(struct pt_regs *regs, unsigned long address, unsigned long error_code)
-{
-  struct vm_area_struct * vma;
-  unsigned long page;
 
-  vma = find_vma(current, address);
+do_page:
+  down(&mm->mmap_sem);
+  vma = find_vma(current->mm, address);
   if (!vma)
-  {
     goto bad_area;
-  }
-
-  if (vma->vm_start <= address){
+  if (vma->vm_start <= address)
     goto good_area;
-  }
   if (!(vma->vm_flags & VM_GROWSDOWN))
-  {
     goto bad_area;
-  }
-  if (vma->vm_end - address > current->rlim[RLIMIT_STACK].rlim_cur)
-  {
+  if (expand_stack(vma, address))
     goto bad_area;
-  }
-  vma->vm_offset -= vma->vm_start - (address & PAGE_MASK);
-
-  vma->vm_start = (address & PAGE_MASK);
   
 good_area:
   /* a write */
-  if (error_code & 2) {
+  if (intel_code & 2) {
     if (!(vma->vm_flags & VM_WRITE))
     {
       goto bad_area;
@@ -187,32 +95,49 @@
   /* a read */
   } else {
     /* protection fault */
-    if (error_code & 1)
+    if (intel_code & 1)
     {
+      printk("prot fault\n");
       goto bad_area;
     }
     if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
     {
+      printk("no read or exec\n");      
       goto bad_area; 
     }
   }
-  handle_mm_fault(vma, address, error_code & 2);
-  flush_page(address);  /* Flush & Invalidate cache - note: address is OK now */  
+  handle_mm_fault(vma, address, intel_code & 2);
+  up(&mm->mmap_sem);  flush_page(address);  /* Flush & Invalidate cache - note: address is OK now */  
   return;
   
 bad_area:
+  up(&mm->mmap_sem);
+
+  /* Did we have an exception handler installed? */
+  if(current->tss.excount != 0) {
+    if(user_mode(regs)) {
+      printk("Exception signalled from user mode!\n");
+    } else {
+#if 0      
+      printk("Exception from kernel mode. pc %x expc %x count %d\n",
+	     regs->nip,current->tss.expc,current->tss.excount);
+#endif      
+      current->tss.excount = 0;
+      regs->gpr[3] = -EFAULT;
+      regs->nip = current->tss.expc;
+      return;
+    }
+  }
+  
   if (user_mode(regs))
   {
-/*    printk("Bad User Area: Addr %x PC %x Task %x pid %d %s\n",
-	   address,regs->nip, current,current->pid,current->comm);*/
-    send_sig(SIGSEGV, current, 1);
+    force_sig(SIGSEGV, current);
     return;
   }
   panic("KERNEL access of bad area PC %x address %x vm_flags %x\n",
 	regs->nip,address,vma->vm_flags);
 }
 
-
 va_to_phys(unsigned long address)
 {
 	pgd_t *dir;
@@ -240,25 +165,8 @@
 	return (0);
 }
 
-
-/*
- * See if an address should be valid in the current context.
- */
-valid_addr(unsigned long addr)
+inline void
+update_mmu_cache(struct vm_area_struct * vma, unsigned long address, pte_t _pte)
 {
-	struct vm_area_struct * vma;
-	for (vma = current->mm->mmap ; ; vma = vma->vm_next)
-	{
-		if (!vma)
-		{
-			return (0);
-		}
-		if (vma->vm_end > addr)
-			break;
-	}
-	if (vma->vm_start <= addr)
-	{
-		return (1);
-	}
-	return (0);
+   MMU_hash_page(&current->tss, address & PAGE_MASK, (pte *)&_pte);
 }