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/*
* linux/arch/alpha/mm/fault.c
*
* Copyright (C) 1995 Linus Torvalds
*/
#include <linux/config.h>
#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 <asm/system.h>
#include <asm/segment.h>
#include <asm/pgtable.h>
extern void die_if_kernel(char *,struct pt_regs *,long);
extern void tbi(unsigned long type, unsigned long arg);
#define tbisi(x) tbi(1,(x))
#define tbisd(x) tbi(2,(x))
#define tbis(x) tbi(3,(x))
/*
* This routine handles page faults. It determines the address,
* and the problem, and then passes it off to handle_mm_fault().
*
* mmcsr:
* 0 = translation not valid
* 1 = access violation
* 2 = fault-on-read
* 3 = fault-on-execute
* 4 = fault-on-write
*
* cause:
* -1 = instruction fetch
* 0 = load
* 1 = store
*/
asmlinkage void do_page_fault(unsigned long address, unsigned long mmcsr, long cause,
unsigned long a3, unsigned long a4, unsigned long a5,
struct pt_regs regs)
{
struct vm_area_struct * vma;
vma = find_vma(current, address);
if (!vma)
goto bad_area;
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)
goto bad_area;
vma->vm_offset -= vma->vm_start - (address & PAGE_MASK);
vma->vm_start = (address & PAGE_MASK);
/*
* Ok, we have a good vm_area for this memory access, so
* we can handle it..
*/
good_area:
if (cause < 0) {
if (!(vma->vm_flags & VM_EXEC))
goto bad_area;
} else if (!cause) {
/* Allow reads even for write-only mappings */
if (!(vma->vm_flags & (VM_READ | VM_WRITE)))
goto bad_area;
} else {
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;
}
tbis(address);
handle_mm_fault(vma, address, cause > 0);
return;
/*
* 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:
if (user_mode(®s)) {
printk("memory violation at pc=%08lx (%08lx)\n", regs.pc, address);
die_if_kernel("oops", ®s, cause);
send_sig(SIGSEGV, current, 1);
return;
}
/*
* Oops. The kernel tried to access some bad page. We'll have to
* terminate things with extreme prejudice.
*/
printk(KERN_ALERT "Unable to handle kernel paging request at virtual address %08lx\n",address);
die_if_kernel("Oops", ®s, cause);
do_exit(SIGKILL);
}
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