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/*
* 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_FORCECOW 0x80
#define FAULT_CODE_PREFETCH 0x04
#define FAULT_CODE_WRITE 0x02
#define FAULT_CODE_USER 0x01
struct pgtable_cache_struct quicklists;
void __bad_pte(pmd_t *pmd)
{
printk("Bad pmd in pte_alloc: %08lx\n", pmd_val(*pmd));
set_pmd(pmd, mk_pmd(BAD_PAGETABLE));
}
pgd_t *get_pgd_slow(void)
{
pgd_t *pgd = (pgd_t *) kmalloc(PTRS_PER_PGD * BYTES_PER_PTR, GFP_KERNEL);
pgd_t *init;
if (pgd) {
init = pgd_offset(&init_mm, 0);
memzero (pgd, USER_PTRS_PER_PGD * BYTES_PER_PTR);
memcpy (pgd + USER_PTRS_PER_PGD, init + USER_PTRS_PER_PGD,
(PTRS_PER_PGD - USER_PTRS_PER_PGD) * BYTES_PER_PTR);
}
return pgd;
}
pte_t *get_pte_slow(pmd_t *pmd, unsigned long offset)
{
pte_t *pte;
pte = (pte_t *) kmalloc (PTRS_PER_PTE * BYTES_PER_PTR, GFP_KERNEL);
if (pmd_none(*pmd)) {
if (pte) {
memzero (pte, PTRS_PER_PTE * BYTES_PER_PTR);
set_pmd(pmd, mk_pmd(pte));
return pte + offset;
}
set_pmd(pmd, mk_pmd(BAD_PAGETABLE));
return NULL;
}
kfree (pte);
if (pmd_bad(*pmd)) {
__bad_pte(pmd);
return NULL;
}
return (pte_t *) pmd_page(*pmd) + offset;
}
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
handle_dataabort (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 (addr >= vma->vm_start)
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_WRITE)) { /* write? */
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, mode & (FAULT_CODE_WRITE|FAULT_CODE_FORCECOW));
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) {
extern int console_loglevel;
cli();
tsk->tss.error_code = mode;
tsk->tss.trap_no = 14;
console_loglevel = 9;
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, 0);
//#endif
force_sig(SIGSEGV, tsk);
while (1);
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 min_addr, unsigned long max_addr, int mode, struct pt_regs *regs)
{
handle_dataabort (min_addr, mode, regs);
if ((min_addr ^ max_addr) >> PAGE_SHIFT)
handle_dataabort (max_addr, mode | FAULT_CODE_FORCECOW, regs);
}
asmlinkage int
do_PrefetchAbort (unsigned long addr, int mode, struct pt_regs *regs)
{
#if 0
if (the memc mapping for this page exists - can check now...) {
printk ("Page in, but got abort (undefined instruction?)\n");
return 0;
}
#endif
handle_dataabort (addr, mode, regs);
return 1;
}
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