1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
|
/*
* arch/mips/mm/fault.c
*
* Copyright (C) 1995 by Ralf Baechle
*/
#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);
/*
* This routine handles page faults. It determines the address,
* and the problem, and then passes it off to one of the appropriate
* routines.
*/
asmlinkage void
do_page_fault(struct pt_regs *regs, unsigned long writeaccess, unsigned long address)
{
struct vm_area_struct * vma;
#if 0
printk("do_page_fault() #1: %s %08lx (epc == %08lx, ra == %08lx)\n",
writeaccess ? "writeaccess to" : "readaccess from",
address, regs->cp0_epc, regs->reg31);
#endif
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 (expand_stack(vma, address))
goto bad_area;
/*
* Ok, we have a good vm_area for this memory access, so
* we can handle it..
*/
good_area:
if (writeaccess) {
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;
} else {
if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
goto bad_area;
}
handle_mm_fault(vma, address, writeaccess);
/* FIXME: This flushes the cache far to often */
sys_cacheflush(address, PAGE_SIZE, BCACHE);
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(regs)) {
current->tss.cp0_badvaddr = address;
current->tss.error_code = writeaccess;
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", regs, writeaccess);
do_exit(SIGKILL);
}
|
