patch-2.1.80 linux/arch/arm/mm/fault-armv.c

• Lines: 201
• Date: Tue Jan 20 16:39:42 1998
• Orig file: v2.1.79/linux/arch/arm/mm/fault-armv.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.79/linux/arch/arm/mm/fault-armv.c linux/arch/arm/mm/fault-armv.c
@@ -0,0 +1,200 @@
+/*
+ *  linux/arch/arm/mm/fault.c
+ *
+ *  Copyright (C) 1995  Linus Torvalds
+ *  Modifications for ARM processor (c) 1995, 1996 Russell King
+ */
+
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/head.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/ptrace.h>
+#include <linux/mman.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/smp_lock.h>
+
+#include <asm/system.h>
+#include <asm/uaccess.h>
+#include <asm/pgtable.h>
+
+#define FAULT_CODE_READ		0x02
+#define FAULT_CODE_USER		0x01
+
+extern void die_if_kernel(char *msg, struct pt_regs *regs, unsigned int err, unsigned int ret);
+
+static void kernel_page_fault (unsigned long addr, int mode, struct pt_regs *regs,
+			       struct task_struct *tsk, struct mm_struct *mm)
+{
+	/*
+	 * Oops. The kernel tried to access some bad page. We'll have to
+	 * terminate things with extreme prejudice.
+	 */
+	pgd_t *pgd;
+	if (addr < PAGE_SIZE)
+	    printk (KERN_ALERT "Unable to handle kernel NULL pointer dereference");
+	else
+	    printk (KERN_ALERT "Unable to handle kernel paging request");
+	printk (" at virtual address %08lx\n", addr);
+	printk (KERN_ALERT "current->tss.memmap = %08lX\n", tsk->tss.memmap);
+	pgd = pgd_offset (mm, addr);
+	printk (KERN_ALERT "*pgd = %08lx", pgd_val (*pgd));
+	if (!pgd_none (*pgd)) {
+		pmd_t *pmd;
+		pmd = pmd_offset (pgd, addr);
+		printk (", *pmd = %08lx", pmd_val (*pmd));
+		if (!pmd_none (*pmd))
+			printk (", *pte = %08lx", pte_val (*pte_offset (pmd, addr)));
+	}
+	printk ("\n");
+	die_if_kernel ("Oops", regs, mode, SIGKILL);
+	do_exit (SIGKILL);
+}
+
+static void page_fault (unsigned long addr, int mode, struct pt_regs *regs)
+{
+	struct task_struct *tsk;
+	struct mm_struct *mm;
+	struct vm_area_struct *vma;
+	unsigned long fixup;
+
+	lock_kernel();
+	tsk = current;
+	mm = tsk->mm;
+
+	down(&mm->mmap_sem);
+	vma = find_vma (mm, addr);
+	if (!vma)
+		goto bad_area;
+	if (vma->vm_start <= addr)
+		goto good_area;
+	if (!(vma->vm_flags & VM_GROWSDOWN) || expand_stack (vma, addr))
+		goto bad_area;
+
+	/*
+	 * Ok, we have a good vm_area for this memory access, so
+	 * we can handle it..
+	 */
+good_area:
+	if (mode & FAULT_CODE_READ) { /* read? */
+		if (!(vma->vm_flags & (VM_READ|VM_EXEC)))
+			goto bad_area;
+	} else {
+		if (!(vma->vm_flags & VM_WRITE))
+			goto bad_area;
+	}
+	handle_mm_fault (tsk, vma, addr & PAGE_MASK, !(mode & FAULT_CODE_READ));
+	up(&mm->mmap_sem);
+	goto out;
+
+	/*
+	 * Something tried to access memory that isn't in our memory map..
+	 * Fix it, but check if it's kernel or user first..
+	 */
+bad_area:
+	up(&mm->mmap_sem);
+	if (mode & FAULT_CODE_USER) {
+		tsk->tss.error_code = mode;
+		tsk->tss.trap_no = 14;
+		printk ("%s: memory violation at pc=0x%08lx, lr=0x%08lx (bad address=0x%08lx, code %d)\n",
+			tsk->comm, regs->ARM_pc, regs->ARM_lr, addr, mode);
+#ifdef DEBUG
+		show_regs (regs);
+		c_backtrace (regs->ARM_fp, regs->ARM_cpsr);
+#endif
+		force_sig(SIGSEGV, tsk);
+		goto out;
+	}
+
+	/* Are we prepared to handle this kernel fault?  */
+	if ((fixup = search_exception_table(regs->ARM_pc)) != 0) {
+		printk(KERN_DEBUG "%s: Exception at [<%lx>] addr=%lx (fixup: %lx)\n",
+			tsk->comm, regs->ARM_pc, addr, fixup);
+		regs->ARM_pc = fixup;
+		goto out;
+	}
+
+	kernel_page_fault (addr, mode, regs, tsk, mm);
+out:
+	unlock_kernel();
+}
+
+/*
+ * Handle a data abort.  Note that we have to handle a range of addresses
+ * on ARM2/3 for ldm.  If both pages are zero-mapped, then we have to force
+ * a copy-on-write
+ */
+asmlinkage void
+do_DataAbort (unsigned long addr, int fsr, int error_code, struct pt_regs *regs)
+{
+	if (user_mode(regs))
+		error_code |= FAULT_CODE_USER;
+
+#define DIE(signr,nam)\
+		force_sig(signr, current);\
+		die_if_kernel(nam, regs, fsr, signr);\
+		break;
+
+	switch (fsr & 15) {
+	case 2:
+		DIE(SIGKILL, "Terminal exception")
+	case 0:
+		DIE(SIGSEGV, "Vector exception")
+	case 1:
+	case 3:
+		DIE(SIGBUS, "Alignment exception")
+	case 12:
+	case 14:
+		DIE(SIGBUS, "External abort on translation")
+	case 9:
+	case 11:
+		DIE(SIGSEGV, "Domain fault")
+	case 13:/* permission fault on section */
+#ifndef DEBUG
+		{
+			unsigned int i, j, a;
+static int count=2;
+if (count-- == 0) while (1);
+			a = regs->ARM_sp;
+			for (j = 0; j < 10; j++) {
+				printk ("%08x: ", a);
+				for (i = 0; i < 8; i += 1, a += 4)
+					printk ("%08lx ", *(unsigned long *)a);
+				printk ("\n");
+			}
+		}
+#endif
+		DIE(SIGSEGV, "Permission fault")
+
+	case 15:/* permission fault on page */
+	case 5:	/* page-table entry descriptor fault */
+	case 7:	/* first-level descriptor fault */
+		page_fault (addr, error_code, regs);
+		break;
+	case 4:
+	case 6:
+		DIE(SIGBUS, "External abort on linefetch")
+	case 8:
+	case 10:
+		DIE(SIGBUS, "External abort on non-linefetch")
+	}
+}
+
+asmlinkage int
+do_PrefetchAbort (unsigned long addr, struct pt_regs *regs)
+{
+#if 0
+	/* does this still apply ? */
+	if (the memc mapping for this page exists - can check now...) {
+		printk ("Page in, but got abort (undefined instruction?)\n");
+		return 0;
+	}
+#endif
+	page_fault (addr, FAULT_CODE_USER|FAULT_CODE_READ, regs);
+	return 1;
+}
+