summaryrefslogtreecommitdiffstats
path: root/arch/ppc/mm/fault.c
blob: 9d0914979d420563234a0435a75db71af72d5bef (plain)
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
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
/*
 *  arch/ppc/mm/fault.c
 *
 *  PowerPC version 
 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 *
 *  Derived from "arch/i386/mm/fault.c"
 *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
 *
 *  Modified by Cort Dougan and Paul Mackerras.
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version
 *  2 of the License, or (at your option) any later version.
 */

#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 <linux/interrupt.h>

#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/mmu.h>
#include <asm/mmu_context.h>
#include <asm/system.h>
#include <asm/uaccess.h>

#if defined(CONFIG_XMON) || defined(CONFIG_KGDB)
extern void (*debugger)(struct pt_regs *);
extern void (*debugger_fault_handler)(struct pt_regs *);
extern int (*debugger_dabr_match)(struct pt_regs *);
int debugger_kernel_faults = 0;
#endif

unsigned long htab_reloads = 0; /* updated by head.S:hash_page() */
unsigned long htab_evicts = 0;  /* updated by head.S:hash_page() */
unsigned long pte_misses = 0; /* updated by do_page_fault() */
unsigned long pte_errors = 0; /* updated by do_page_fault() */
unsigned int probingmem = 0;

extern void die_if_kernel(char *, struct pt_regs *, long);
void bad_page_fault(struct pt_regs *, unsigned long);
void do_page_fault(struct pt_regs *, unsigned long, unsigned long);

/*
 * The error_code parameter is DSISR for a data fault, SRR1 for
 * an instruction fault.
 */
void do_page_fault(struct pt_regs *regs, unsigned long address,
		   unsigned long error_code)
{
	struct vm_area_struct * vma;
	struct mm_struct *mm = current->mm;

	/*printk("address: %08lx code: %08lx %s%s%s%s%s%s\n",
	       address,error_code,
	       (error_code&0x40000000)?"604 tlb&htab miss ":"",
	       (error_code&0x20000000)?"603 tlbmiss ":"",
	       (error_code&0x02000000)?"write ":"",
	       (error_code&0x08000000)?"prot ":"",
	       (error_code&0x95700000)?"I/O ":"",
	       (regs->trap == 0x400)?"instr":"data"
	       );*/
	       
#if defined(CONFIG_XMON) || defined(CONFIG_KGDB)
	if (debugger_fault_handler && regs->trap == 0x300) {
		debugger_fault_handler(regs);
		return;
	}
	if (error_code & 0x00400000) {
		/* DABR match */
		if (debugger_dabr_match(regs))
			return;
	}
#endif
	if (in_interrupt()) {
		static int complained;
		if (complained < 20) {
			++complained;
			printk("page fault in interrupt handler, addr=%lx\n",
			       address);
			show_regs(regs);
#if defined(CONFIG_XMON) || defined(CONFIG_KGDB)
			if (debugger_kernel_faults)
				debugger(regs);
#endif
		}
	}
	if (current == NULL) {
		bad_page_fault(regs, address);
		return;
	}
	down(&mm->mmap_sem);
	vma = find_vma(mm, 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;

good_area:
#ifdef CONFIG_6xx
	if (error_code & 0x95700000)
		/* an error such as lwarx to I/O controller space,
		   address matching DABR, eciwx, etc. */
#endif /* CONFIG_6xx */
#ifdef CONFIG_8xx
        /* The MPC8xx seems to always set 0x80000000, which is
         * "undefined".  Of those that can be set, this is the only
         * one which seems bad.
         */
	if (error_code & 0x10000000)
                /* Guarded storage error. */
#endif /* CONFIG_8xx */
		goto bad_area;
	
	
	/* a write */
	if (error_code & 0x02000000) {
		if (!(vma->vm_flags & VM_WRITE))
			goto bad_area;
	/* a read */
	} else {
		/* protection fault */
		if (error_code & 0x08000000)
			goto bad_area;
		if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
			goto bad_area;
	}
	handle_mm_fault(current, vma, address, error_code & 0x02000000);
	up(&mm->mmap_sem);
	/*
	 * keep track of tlb+htab misses that are good addrs but
	 * just need pte's created via handle_mm_fault()
	 * -- Cort
	 */
	pte_misses++;
	return;

bad_area:

	up(&mm->mmap_sem);
	pte_errors++;	
	bad_page_fault(regs, address);
}

void
bad_page_fault(struct pt_regs *regs, unsigned long address)
{
	unsigned long fixup;
#if 0	
	extern unsigned long video_mem_base;
	extern unsigned long video_mem_term;
	
	/*
	 * Remap video IO areas for buggy X servers.
	 * The S3 server wants direct access to video memory
	 * at 0x8000 0000 and 0xc000 0000 on prep systems, but
	 * we don't allow that AND we remap the io areas so it's not
	 * even there!
	 * So, for this task only give a virtual=physical mapping of the
	 * video mem.
	 * -- Cort
	 */
	if ( is_prep && user_mode(regs) )
	{
			printk("%s/%d: fault on %x\n",
			       current->comm,current->pid,address);
			printk("mapping: %x -> %x\n",
			       address&PAGE_MASK, address&PAGE_MASK);
			map_page(current,address&PAGE_MASK,address&PAGE_MASK,
				 _PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_RW | _PAGE_DIRTY | _PAGE_HWWRITE|_PAGE_NO_CACHE|_PAGE_WRITETHRU);
			return;
	}
#endif	
	
	if (user_mode(regs)) {
		force_sig(SIGSEGV, current);
		return;
	}
	
	/* Are we prepared to handle this fault?  */
	if ((fixup = search_exception_table(regs->nip)) != 0) {
		regs->nip = fixup;
		return;
	}

	/* kernel has accessed a bad area */
	show_regs(regs);
	print_backtrace( (unsigned long *)regs->gpr[1] );
#if defined(CONFIG_XMON) || defined(CONFIG_KGDB)
	if (debugger_kernel_faults)
		debugger(regs);
#endif
	panic("kernel access of bad area pc %lx lr %lx address %lX tsk %s/%d",
	      regs->nip,regs->link,address,current->comm,current->pid);
}

/*
 * I need a va to pte function for the MPC8xx so I can set the cache
 * attributes on individual pages used by the Communication Processor
 * Module.
 */
pte_t *va_to_pte(struct task_struct *tsk, unsigned long address)
{
        pgd_t *dir;
        pmd_t *pmd;
        pte_t *pte;
        
        dir = pgd_offset(tsk->mm, address & PAGE_MASK);
        if (dir)
        {
                pmd = pmd_offset(dir, address & PAGE_MASK);
                if (pmd && pmd_present(*pmd))
                {
                        pte = pte_offset(pmd, address & PAGE_MASK);
                        if (pte && pte_present(*pte))
                        {
                                return(pte);
                        }
                } else
                {
                        return (0);
                }
        } else
        {
                return (0);
        }
        return (0);
}

unsigned long va_to_phys(unsigned long address)
{
	pgd_t *dir;
	pmd_t *pmd;
	pte_t *pte;
	
	dir = pgd_offset(current->mm, address & PAGE_MASK);
	if (dir)
	{
		pmd = pmd_offset(dir, address & PAGE_MASK);
		if (pmd && pmd_present(*pmd))
		{
			pte = pte_offset(pmd, address & PAGE_MASK);
			if (pte && pte_present(*pte))
			{
				return(pte_page(*pte) | (address & ~(PAGE_MASK-1)));
			}
		} else
		{
			return (0);
		}
	} else
	{
		return (0);
	}
	return (0);
}

void
print_8xx_pte(struct mm_struct *mm, unsigned long addr)
{
        pgd_t * pgd;
        pmd_t * pmd;
        pte_t * pte;

        printk(" pte @ 0x%8lx: ", addr);
        pgd = pgd_offset(mm, addr & PAGE_MASK);
        if (pgd) {
                pmd = pmd_offset(pgd, addr & PAGE_MASK);
                if (pmd && pmd_present(*pmd)) {
                        pte = pte_offset(pmd, addr & PAGE_MASK);
                        if (pte) {
                                printk(" (0x%08lx)->(0x%08lx)->0x%08lx\n",
                                        (long)pgd, (long)pte, (long)pte_val(*pte));
                        }
                        else {
                                printk("no pte\n");
                        }
                }
                else {
                        printk("no pmd\n");
                }
        }
        else {
                printk("no pgd\n");
        }
}

int
get_8xx_pte(struct mm_struct *mm, unsigned long addr)
{
        pgd_t * pgd;
        pmd_t * pmd;
        pte_t * pte;
        int     retval = 0;

        pgd = pgd_offset(mm, addr & PAGE_MASK);
        if (pgd) {
                pmd = pmd_offset(pgd, addr & PAGE_MASK);
                if (pmd && pmd_present(*pmd)) {
                        pte = pte_offset(pmd, addr & PAGE_MASK);
                        if (pte) {
                                        retval = (int)pte_val(*pte);
                        }
                }
        }
        return(retval);
}

#if 0
/*
 * Misc debugging functions.  Please leave them here. -- Cort
 */
void print_pte(struct _PTE p)
{
	printk(
"%08x %08x vsid: %06x h: %01x api: %02x rpn: %05x rcwimg: %d%d%d%d%d%d pp: %02x\n",
		*((unsigned long *)(&p)), *((long *)&p+1),
		p.vsid, p.h, p.api, p.rpn,
		p.r,p.c,p.w,p.i,p.m,p.g,p.pp);
}

/*
 * Search the hw hash table for a mapping to the given physical
 * address. -- Cort
 */
unsigned long htab_phys_to_va(unsigned long address)
{
	extern PTE *Hash, *Hash_end;
	PTE *ptr;

	for ( ptr = Hash ; ptr < Hash_end ; ptr++ )
	{
		if ( ptr->rpn == (address>>12) )
			printk("phys %08lX -> va ???\n",
			       address);
	}
}
#endif