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[/] [or1k/] [trunk/] [uclinux/] [uClinux-2.0.x/] [arch/] [m68k/] [mm/] [fault.c] - Blame information for rev 1765

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/*
 *  linux/arch/m68k/mm/fault.c
 *
 *  Copyright (C) 1995  Hamish Macdonald
 */
 
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/kernel.h>
#include <linux/ptrace.h>
 
#include <asm/system.h>
#include <asm/pgtable.h>
 
extern void die_if_kernel(char *, struct pt_regs *, long);
 
/*
 * This routine handles page faults.  It determines the problem, and
 * then passes it off to one of the appropriate routines.
 *
 * error_code:
 *      bit 0 == 0 means no page found, 1 means protection fault
 *      bit 1 == 0 means read, 1 means write
 *
 * If this routine detects a bad access, it returns 1, otherwise it
 * returns 0.
 */
asmlinkage int do_page_fault(struct pt_regs *regs, unsigned long address,
                              unsigned long error_code)
{
        struct vm_area_struct * vma;
 
#ifdef DEBUG
        printk ("regs->sr=%#x, regs->pc=%#lx, address=%#lx, %ld, %p\n",
                regs->sr, regs->pc, address, error_code,
                current->tss.pagedir_v);
#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 (user_mode(regs)) {
                /* Accessing the stack below usp is always a bug.  The
                   "+ 256" is there due to some instructions doing
                   pre-decrement on the stack and that doesn't show up
                   until later.  */
                if (address + 256 < rdusp())
                        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:
        /*
         * was it a write?
         */
        if (error_code & 2) {
          if (!(vma->vm_flags & VM_WRITE))
            goto bad_area;
        } else {
                /* read with protection fault? */
          if (error_code & 1)
            goto bad_area;
          if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
            goto bad_area;
        }
        if (error_code & 1) {
                do_wp_page(current, vma, address, error_code & 2);
                return 0;
        }
        do_no_page(current, vma, address, error_code & 2);
 
        /* There seems to be a missing invalidate somewhere in do_no_page.
         * Until I found it, this one cures the problem and makes
         * 1.2 run on the 68040 (Martin Apel).
         */
        flush_tlb_all();
 
        return 0;
 
/*
 * 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)) {
                /* User memory access */
                force_sig (SIGSEGV, current);
                return 1;
        }
 
/*
 * Oops. The kernel tried to access some bad page. We'll have to
 * terminate things with extreme prejudice.
 */
        if ((unsigned long) address < PAGE_SIZE) {
                printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");
        } else
                printk(KERN_ALERT "Unable to handle kernel access");
        printk(" at virtual address %08lx\n",address);
        die_if_kernel("Oops", regs, error_code);
        do_exit(SIGKILL);
 
        return 1;
}

Line No.	Rev	Author	Line
1	199	simons	`/*`
2			`* linux/arch/m68k/mm/fault.c`
3			`*`
4			`* Copyright (C) 1995 Hamish Macdonald`
5			`*/`
6
7			`#include <linux/mman.h>`
8			`#include <linux/mm.h>`
9			`#include <linux/kernel.h>`
10			`#include <linux/ptrace.h>`
11
12			`#include <asm/system.h>`
13			`#include <asm/pgtable.h>`
14
15			`extern void die_if_kernel(char , struct pt_regs , long);`
16
17			`/*`
18			`* This routine handles page faults. It determines the problem, and`
19			`* then passes it off to one of the appropriate routines.`
20			`*`
21			`* error_code:`
22			`* bit 0 == 0 means no page found, 1 means protection fault`
23			`* bit 1 == 0 means read, 1 means write`
24			`*`
25			`* If this routine detects a bad access, it returns 1, otherwise it`
26			`* returns 0.`
27			`*/`
28			`asmlinkage int do_page_fault(struct pt_regs *regs, unsigned long address,`
29			`unsigned long error_code)`
30			`{`
31			`struct vm_area_struct * vma;`
32
33			`#ifdef DEBUG`
34			`printk ("regs->sr=%#x, regs->pc=%#lx, address=%#lx, %ld, %p\n",`
35			`regs->sr, regs->pc, address, error_code,`
36			`current->tss.pagedir_v);`
37			`#endif`
38
39			`vma = find_vma(current, address);`
40			`if (!vma)`
41			`goto bad_area;`
42			`if (vma->vm_start <= address)`
43			`goto good_area;`
44			`if (!(vma->vm_flags & VM_GROWSDOWN))`
45			`goto bad_area;`
46			`if (user_mode(regs)) {`
47			`/* Accessing the stack below usp is always a bug. The`
48			`"+ 256" is there due to some instructions doing`
49			`pre-decrement on the stack and that doesn't show up`
50			`until later. */`
51			`if (address + 256 < rdusp())`
52			`goto bad_area;`
53			`}`
54			`if (expand_stack(vma, address))`
55			`goto bad_area;`
56
57			`/*`
58			`* Ok, we have a good vm_area for this memory access, so`
59			`* we can handle it..`
60			`*/`
61			`good_area:`
62			`/*`
63			`* was it a write?`
64			`*/`
65			`if (error_code & 2) {`
66			`if (!(vma->vm_flags & VM_WRITE))`
67			`goto bad_area;`
68			`} else {`
69			`/* read with protection fault? */`
70			`if (error_code & 1)`
71			`goto bad_area;`
72			`if (!(vma->vm_flags & (VM_READ \| VM_EXEC)))`
73			`goto bad_area;`
74			`}`
75			`if (error_code & 1) {`
76			`do_wp_page(current, vma, address, error_code & 2);`
77			`return 0;`
78			`}`
79			`do_no_page(current, vma, address, error_code & 2);`
80
81			`/* There seems to be a missing invalidate somewhere in do_no_page.`
82			`* Until I found it, this one cures the problem and makes`
83			`* 1.2 run on the 68040 (Martin Apel).`
84			`*/`
85			`flush_tlb_all();`
86
87			`return 0;`
88
89			`/*`
90			`* Something tried to access memory that isn't in our memory map..`
91			`* Fix it, but check if it's kernel or user first..`
92			`*/`
93			`bad_area:`
94			`if (user_mode(regs)) {`
95			`/* User memory access */`
96			`force_sig (SIGSEGV, current);`
97			`return 1;`
98			`}`
99
100			`/*`
101			`* Oops. The kernel tried to access some bad page. We'll have to`
102			`* terminate things with extreme prejudice.`
103			`*/`
104			`if ((unsigned long) address < PAGE_SIZE) {`
105			`printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");`
106			`} else`
107			`printk(KERN_ALERT "Unable to handle kernel access");`
108			`printk(" at virtual address %08lx\n",address);`
109			`die_if_kernel("Oops", regs, error_code);`
110			`do_exit(SIGKILL);`
111
112			`return 1;`
113			`}`

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[/] [or1k/] [trunk/] [uclinux/] [uClinux-2.0.x/] [arch/] [m68k/] [mm/] [fault.c] - Blame information for rev 1765