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[/] [or1k/] [trunk/] [linux/] [linux-2.4/] [arch/] [parisc/] [mm/] [fault.c] - Blame information for rev 1765

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/* $Id: fault.c,v 1.1.1.1 2004-04-15 01:35:21 phoenix Exp $
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 *
 * Copyright (C) 1995, 1996, 1997, 1998 by Ralf Baechle
 * Copyright 1999 SuSE GmbH (Philipp Rumpf, prumpf@tux.org)
 * Copyright 1999 Hewlett Packard Co.
 *
 */
 
#include <linux/mm.h>
#include <linux/ptrace.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
 
#include <asm/uaccess.h>
#include <asm/traps.h>
 
#define PRINT_USER_FAULTS /* (turn this on if you want user faults to be */
                         /*  dumped to the console via printk)          */
 
 
/* Defines for parisc_acctyp()  */
#define READ            0
#define WRITE           1
 
/* Various important other fields */
#define bit22set(x)             (x & 0x00000200)
#define bits23_25set(x)         (x & 0x000001c0)
#define isGraphicsFlushRead(x)  ((x & 0xfc003fdf) == 0x04001a80)
                                /* extended opcode is 0x6a */
 
#define BITSSET         0x1c0   /* for identifying LDCW */
 
/*
 * parisc_acctyp(unsigned int inst) --
 *    Given a PA-RISC memory access instruction, determine if the
 *    the instruction would perform a memory read or memory write
 *    operation.
 *
 *    This function assumes that the given instruction is a memory access
 *    instruction (i.e. you should really only call it if you know that
 *    the instruction has generated some sort of a memory access fault).
 *
 * Returns:
 *   VM_READ  if read operation
 *   VM_WRITE if write operation
 *   VM_EXEC  if execute operation
 */
static unsigned long
parisc_acctyp(unsigned long code, unsigned int inst)
{
        if (code == 6 || code == 16)
            return VM_EXEC;
 
        switch (inst & 0xf0000000) {
        case 0x40000000: /* load */
        case 0x50000000: /* new load */
                return VM_READ;
 
        case 0x60000000: /* store */
        case 0x70000000: /* new store */
                return VM_WRITE;
 
        case 0x20000000: /* coproc */
        case 0x30000000: /* coproc2 */
                if (bit22set(inst))
                        return VM_WRITE;
 
        case 0x0: /* indexed/memory management */
                if (bit22set(inst)) {
                        /*
                         * Check for the 'Graphics Flush Read' instruction.
                         * It resembles an FDC instruction, except for bits
                         * 20 and 21. Any combination other than zero will
                         * utilize the block mover functionality on some
                         * older PA-RISC platforms.  The case where a block
                         * move is performed from VM to graphics IO space
                         * should be treated as a READ.
                         *
                         * The significance of bits 20,21 in the FDC
                         * instruction is:
                         *
                         *   00  Flush data cache (normal instruction behavior)
                         *   01  Graphics flush write  (IO space -> VM)
                         *   10  Graphics flush read   (VM -> IO space)
                         *   11  Graphics flush read/write (VM <-> IO space)
                         */
                        if (isGraphicsFlushRead(inst))
                                return VM_READ;
                        return VM_WRITE;
                } else {
                        /*
                         * Check for LDCWX and LDCWS (semaphore instructions).
                         * If bits 23 through 25 are all 1's it is one of
                         * the above two instructions and is a write.
                         *
                         * Note: With the limited bits we are looking at,
                         * this will also catch PROBEW and PROBEWI. However,
                         * these should never get in here because they don't
                         * generate exceptions of the type:
                         *   Data TLB miss fault/data page fault
                         *   Data memory protection trap
                         */
                        if (bits23_25set(inst) == BITSSET)
                                return VM_WRITE;
                }
                return VM_READ; /* Default */
        }
        return VM_READ; /* Default */
}
 
#undef bit22set
#undef bits23_25set
#undef isGraphicsFlushRead
#undef BITSSET
 
 
#if 0
/* This is the treewalk to find a vma which is the highest that has
 * a start < addr.  We're using find_vma_prev instead right now, but
 * we might want to use this at some point in the future.  Probably
 * not, but I want it committed to CVS so I don't lose it :-)
 */
                        while (tree != vm_avl_empty) {
                                if (tree->vm_start > addr) {
                                        tree = tree->vm_avl_left;
                                } else {
                                        prev = tree;
                                        if (prev->vm_next == NULL)
                                                break;
                                        if (prev->vm_next->vm_start > addr)
                                                break;
                                        tree = tree->vm_avl_right;
                                }
                        }
#endif
 
void do_page_fault(struct pt_regs *regs, unsigned long code,
                              unsigned long address)
{
        struct vm_area_struct *vma, *prev_vma;
        struct task_struct *tsk = current;
        struct mm_struct *mm = tsk->mm;
        const struct exception_table_entry *fix;
        unsigned long acc_type;
 
        if (in_interrupt() || !mm)
                goto no_context;
 
        down_read(&mm->mmap_sem);
        vma = find_vma_prev(mm, address, &prev_vma);
        if (!vma || address < vma->vm_start)
                goto check_expansion;
/*
 * Ok, we have a good vm_area for this memory access. We still need to
 * check the access permissions.
 */
 
good_area:
 
        acc_type = parisc_acctyp(code,regs->iir);
 
        if ((vma->vm_flags & acc_type) != acc_type)
                goto bad_area;
 
        /*
         * If for any reason at all we couldn't handle the fault, make
         * sure we exit gracefully rather than endlessly redo the
         * fault.
         */
 
        switch (handle_mm_fault(mm, vma, address, (acc_type & VM_WRITE) != 0)) {
              case 1:
                ++current->min_flt;
                break;
              case 2:
                ++current->maj_flt;
                break;
              case 0:
                /*
                 * We ran out of memory, or some other thing happened
                 * to us that made us unable to handle the page fault
                 * gracefully.
                 */
                goto bad_area;
              default:
                goto out_of_memory;
        }
        up_read(&mm->mmap_sem);
        return;
 
check_expansion:
        vma = prev_vma;
        if (vma && (expand_stack(vma, address) == 0))
                goto good_area;
 
/*
 * Something tried to access memory that isn't in our memory map..
 */
bad_area:
        up_read(&mm->mmap_sem);
 
        if (user_mode(regs)) {
                struct siginfo si;
 
#ifdef PRINT_USER_FAULTS
                printk(KERN_DEBUG "\n");
                printk(KERN_DEBUG "do_page_fault() pid=%d command='%s' type=%lu address=0x%08lx\n",
                    tsk->pid, tsk->comm, code, address);
                if (vma) {
                        printk(KERN_DEBUG "vm_start = 0x%08lx, vm_end = 0x%08lx\n",
                                        vma->vm_start, vma->vm_end);
                }
                show_regs(regs);
#endif
                /* FIXME: actually we need to get the signo and code correct */
                si.si_signo = SIGSEGV;
                si.si_errno = 0;
                si.si_code = SEGV_MAPERR;
                si.si_addr = (void *) address;
                force_sig_info(SIGSEGV, &si, current);
                return;
        }
 
no_context:
 
        if (!user_mode(regs)) {
 
                fix = search_exception_table(regs->iaoq[0]);
 
                if (fix) {
 
                        if (fix->skip & 1)
                                regs->gr[8] = -EFAULT;
                        if (fix->skip & 2)
                                regs->gr[9] = 0;
 
                        regs->iaoq[0] += ((fix->skip) & ~3);
 
                        /*
                         * NOTE: In some cases the faulting instruction
                         * may be in the delay slot of a branch. We
                         * don't want to take the branch, so we don't
                         * increment iaoq[1], instead we set it to be
                         * iaoq[0]+4, and clear the B bit in the PSW
                         */
 
                        regs->iaoq[1] = regs->iaoq[0] + 4;
                        regs->gr[0] &= ~PSW_B; /* IPSW in gr[0] */
 
                        return;
                }
        }
 
        parisc_terminate("Bad Address (null pointer deref?)", regs, code, address);
        /* NOT REACHED! */
 
  out_of_memory:
        up_read(&mm->mmap_sem);
        printk(KERN_CRIT "VM: killing process %s\n", current->comm);
        if (user_mode(regs))
                do_exit(SIGKILL);
        goto no_context;
}

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[/] [or1k/] [trunk/] [linux/] [linux-2.4/] [arch/] [parisc/] [mm/] [fault.c] - Blame information for rev 1765

Line No.	Rev	Author	Line
1	1275	phoenix	`/* $Id: fault.c,v 1.1.1.1 2004-04-15 01:35:21 phoenix Exp $`
2			`*`
3			`* This file is subject to the terms and conditions of the GNU General Public`
4			`* License. See the file "COPYING" in the main directory of this archive`
5			`* for more details.`
6			`*`
7			`*`
8			`* Copyright (C) 1995, 1996, 1997, 1998 by Ralf Baechle`
9			`* Copyright 1999 SuSE GmbH (Philipp Rumpf, prumpf@tux.org)`
10			`* Copyright 1999 Hewlett Packard Co.`
11			`*`
12			`*/`
13
14			`#include <linux/mm.h>`
15			`#include <linux/ptrace.h>`
16			`#include <linux/sched.h>`
17			`#include <linux/interrupt.h>`
18
19			`#include <asm/uaccess.h>`
20			`#include <asm/traps.h>`
21
22			`#define PRINT_USER_FAULTS /* (turn this on if you want user faults to be */`
23			`/* dumped to the console via printk) */`
24
25
26			`/* Defines for parisc_acctyp() */`
27			`#define READ 0`
28			`#define WRITE 1`
29
30			`/* Various important other fields */`
31			`#define bit22set(x) (x & 0x00000200)`
32			`#define bits23_25set(x) (x & 0x000001c0)`
33			`#define isGraphicsFlushRead(x) ((x & 0xfc003fdf) == 0x04001a80)`
34			`/* extended opcode is 0x6a */`
35
36			`#define BITSSET 0x1c0 /* for identifying LDCW */`
37
38			`/*`
39			`* parisc_acctyp(unsigned int inst) --`
40			`* Given a PA-RISC memory access instruction, determine if the`
41			`* the instruction would perform a memory read or memory write`
42			`* operation.`
43			`*`
44			`* This function assumes that the given instruction is a memory access`
45			`* instruction (i.e. you should really only call it if you know that`
46			`* the instruction has generated some sort of a memory access fault).`
47			`*`
48			`* Returns:`
49			`* VM_READ if read operation`
50			`* VM_WRITE if write operation`
51			`* VM_EXEC if execute operation`
52			`*/`
53			`static unsigned long`
54			`parisc_acctyp(unsigned long code, unsigned int inst)`
55			`{`
56			`if (code == 6 \|\| code == 16)`
57			`return VM_EXEC;`
58
59			`switch (inst & 0xf0000000) {`
60			`case 0x40000000: /* load */`
61			`case 0x50000000: /* new load */`
62			`return VM_READ;`
63
64			`case 0x60000000: /* store */`
65			`case 0x70000000: /* new store */`
66			`return VM_WRITE;`
67
68			`case 0x20000000: /* coproc */`
69			`case 0x30000000: /* coproc2 */`
70			`if (bit22set(inst))`
71			`return VM_WRITE;`
72
73			`case 0x0: /* indexed/memory management */`
74			`if (bit22set(inst)) {`
75			`/*`
76			`* Check for the 'Graphics Flush Read' instruction.`
77			`* It resembles an FDC instruction, except for bits`
78			`* 20 and 21. Any combination other than zero will`
79			`* utilize the block mover functionality on some`
80			`* older PA-RISC platforms. The case where a block`
81			`* move is performed from VM to graphics IO space`
82			`* should be treated as a READ.`
83			`*`
84			`* The significance of bits 20,21 in the FDC`
85			`* instruction is:`
86			`*`
87			`* 00 Flush data cache (normal instruction behavior)`
88			`* 01 Graphics flush write (IO space -> VM)`
89			`* 10 Graphics flush read (VM -> IO space)`
90			`* 11 Graphics flush read/write (VM <-> IO space)`
91			`*/`
92			`if (isGraphicsFlushRead(inst))`
93			`return VM_READ;`
94			`return VM_WRITE;`
95			`} else {`
96			`/*`
97			`* Check for LDCWX and LDCWS (semaphore instructions).`
98			`* If bits 23 through 25 are all 1's it is one of`
99			`* the above two instructions and is a write.`
100			`*`
101			`* Note: With the limited bits we are looking at,`
102			`* this will also catch PROBEW and PROBEWI. However,`
103			`* these should never get in here because they don't`
104			`* generate exceptions of the type:`
105			`* Data TLB miss fault/data page fault`
106			`* Data memory protection trap`
107			`*/`
108			`if (bits23_25set(inst) == BITSSET)`
109			`return VM_WRITE;`
110			`}`
111			`return VM_READ; /* Default */`
112			`}`
113			`return VM_READ; /* Default */`
114			`}`
115
116			`#undef bit22set`
117			`#undef bits23_25set`
118			`#undef isGraphicsFlushRead`
119			`#undef BITSSET`
120
121
122			`#if 0`
123			`/* This is the treewalk to find a vma which is the highest that has`
124			`* a start < addr. We're using find_vma_prev instead right now, but`
125			`* we might want to use this at some point in the future. Probably`
126			`* not, but I want it committed to CVS so I don't lose it :-)`
127			`*/`
128			`while (tree != vm_avl_empty) {`
129			`if (tree->vm_start > addr) {`
130			`tree = tree->vm_avl_left;`
131			`} else {`
132			`prev = tree;`
133			`if (prev->vm_next == NULL)`
134			`break;`
135			`if (prev->vm_next->vm_start > addr)`
136			`break;`
137			`tree = tree->vm_avl_right;`
138			`}`
139			`}`
140			`#endif`
141
142			`void do_page_fault(struct pt_regs *regs, unsigned long code,`
143			`unsigned long address)`
144			`{`
145			`struct vm_area_struct vma, prev_vma;`
146			`struct task_struct *tsk = current;`
147			`struct mm_struct *mm = tsk->mm;`
148			`const struct exception_table_entry *fix;`
149			`unsigned long acc_type;`
150
151			`if (in_interrupt() \|\| !mm)`
152			`goto no_context;`
153
154			`down_read(&mm->mmap_sem);`
155			`vma = find_vma_prev(mm, address, &prev_vma);`
156			`if (!vma \|\| address < vma->vm_start)`
157			`goto check_expansion;`
158			`/*`
159			`* Ok, we have a good vm_area for this memory access. We still need to`
160			`* check the access permissions.`
161			`*/`
162
163			`good_area:`
164
165			`acc_type = parisc_acctyp(code,regs->iir);`
166
167			`if ((vma->vm_flags & acc_type) != acc_type)`
168			`goto bad_area;`
169
170			`/*`
171			`* If for any reason at all we couldn't handle the fault, make`
172			`* sure we exit gracefully rather than endlessly redo the`
173			`* fault.`
174			`*/`
175
176			`switch (handle_mm_fault(mm, vma, address, (acc_type & VM_WRITE) != 0)) {`
177			`case 1:`
178			`++current->min_flt;`
179			`break;`
180			`case 2:`
181			`++current->maj_flt;`
182			`break;`
183			`case 0:`
184			`/*`
185			`* We ran out of memory, or some other thing happened`
186			`* to us that made us unable to handle the page fault`
187			`* gracefully.`
188			`*/`
189			`goto bad_area;`
190			`default:`
191			`goto out_of_memory;`
192			`}`
193			`up_read(&mm->mmap_sem);`
194			`return;`
195
196			`check_expansion:`
197			`vma = prev_vma;`
198			`if (vma && (expand_stack(vma, address) == 0))`
199			`goto good_area;`
200
201			`/*`
202			`* Something tried to access memory that isn't in our memory map..`
203			`*/`
204			`bad_area:`
205			`up_read(&mm->mmap_sem);`
206
207			`if (user_mode(regs)) {`
208			`struct siginfo si;`
209
210			`#ifdef PRINT_USER_FAULTS`
211			`printk(KERN_DEBUG "\n");`
212			`printk(KERN_DEBUG "do_page_fault() pid=%d command='%s' type=%lu address=0x%08lx\n",`
213			`tsk->pid, tsk->comm, code, address);`
214			`if (vma) {`
215			`printk(KERN_DEBUG "vm_start = 0x%08lx, vm_end = 0x%08lx\n",`
216			`vma->vm_start, vma->vm_end);`
217			`}`
218			`show_regs(regs);`
219			`#endif`
220			`/* FIXME: actually we need to get the signo and code correct */`
221			`si.si_signo = SIGSEGV;`
222			`si.si_errno = 0;`
223			`si.si_code = SEGV_MAPERR;`
224			`si.si_addr = (void *) address;`
225			`force_sig_info(SIGSEGV, &si, current);`
226			`return;`
227			`}`
228
229			`no_context:`
230
231			`if (!user_mode(regs)) {`
232
233			`fix = search_exception_table(regs->iaoq[0]);`
234
235			`if (fix) {`
236
237			`if (fix->skip & 1)`
238			`regs->gr[8] = -EFAULT;`
239			`if (fix->skip & 2)`
240			`regs->gr[9] = 0;`
241
242			`regs->iaoq[0] += ((fix->skip) & ~3);`
243
244			`/*`
245			`* NOTE: In some cases the faulting instruction`
246			`* may be in the delay slot of a branch. We`
247			`* don't want to take the branch, so we don't`
248			`* increment iaoq[1], instead we set it to be`
249			`* iaoq[0]+4, and clear the B bit in the PSW`
250			`*/`
251
252			`regs->iaoq[1] = regs->iaoq[0] + 4;`
253			`regs->gr[0] &= ~PSW_B; /* IPSW in gr[0] */`
254
255			`return;`
256			`}`
257			`}`
258
259			`parisc_terminate("Bad Address (null pointer deref?)", regs, code, address);`
260			`/* NOT REACHED! */`
261
262			`out_of_memory:`
263			`up_read(&mm->mmap_sem);`
264			`printk(KERN_CRIT "VM: killing process %s\n", current->comm);`
265			`if (user_mode(regs))`
266			`do_exit(SIGKILL);`
267			`goto no_context;`
268			`}`