aboutsummaryrefslogtreecommitdiffstats
path: root/arch/frv/mm/fault.c
blob: 8b3eb50c510544c57d9a0cbc4093575400ba52cf (plain) (blame)
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
/*
 *  linux/arch/frv/mm/fault.c
 *
 * Copyright (C) 2003 Red Hat, Inc. All Rights Reserved.
 * - Written by David Howells (dhowells@redhat.com)
 * - Derived from arch/m68knommu/mm/fault.c
 *   - Copyright (C) 1998  D. Jeff Dionne <jeff@lineo.ca>,
 *   - Copyright (C) 2000  Lineo, Inc.  (www.lineo.com)
 *
 *  Based on:
 *
 *  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 <linux/hardirq.h>

#include <asm/system.h>
#include <asm/pgtable.h>
#include <asm/uaccess.h>
#include <asm/gdb-stub.h>

/*****************************************************************************/
/*
 * This routine handles page faults.  It determines the problem, and
 * then passes it off to one of the appropriate routines.
 */
asmlinkage void do_page_fault(int datammu, unsigned long esr0, unsigned long ear0)
{
	struct vm_area_struct *vma;
	struct mm_struct *mm;
	unsigned long _pme, lrai, lrad, fixup;
	siginfo_t info;
	pgd_t *pge;
	pud_t *pue;
	pte_t *pte;
	int write;

#if 0
	const char *atxc[16] = {
		[0x0] = "mmu-miss", [0x8] = "multi-dat", [0x9] = "multi-sat",
		[0xa] = "tlb-miss", [0xc] = "privilege", [0xd] = "write-prot",
	};

	printk("do_page_fault(%d,%lx [%s],%lx)\n",
	       datammu, esr0, atxc[esr0 >> 20 & 0xf], ear0);
#endif

	mm = current->mm;

	/*
	 * We fault-in kernel-space virtual memory on-demand. The
	 * 'reference' page table is init_mm.pgd.
	 *
	 * NOTE! We MUST NOT take any locks for this case. We may
	 * be in an interrupt or a critical region, and should
	 * only copy the information from the master page table,
	 * nothing more.
	 *
	 * This verifies that the fault happens in kernel space
	 * and that the fault was a page not present (invalid) error
	 */
	if (!user_mode(__frame) && (esr0 & ESR0_ATXC) == ESR0_ATXC_AMRTLB_MISS) {
		if (ear0 >= VMALLOC_START && ear0 < VMALLOC_END)
			goto kernel_pte_fault;
		if (ear0 >= PKMAP_BASE && ear0 < PKMAP_END)
			goto kernel_pte_fault;
	}

	info.si_code = SEGV_MAPERR;

	/*
	 * If we're in an interrupt or have no user
	 * context, we must not take the fault..
	 */
	if (in_interrupt() || !mm)
		goto no_context;

	down_read(&mm->mmap_sem);

	vma = find_vma(mm, ear0);
	if (!vma)
		goto bad_area;
	if (vma->vm_start <= ear0)
		goto good_area;
	if (!(vma->vm_flags & VM_GROWSDOWN))
		goto bad_area;

	if (user_mode(__frame)) {
		/*
		 * accessing the stack below %esp is always a bug.
		 * The "+ 32" is there due to some instructions (like
		 * pusha) doing post-decrement on the stack and that
		 * doesn't show up until later..
		 */
		if ((ear0 & PAGE_MASK) + 2 * PAGE_SIZE < __frame->sp) {
#if 0
			printk("[%d] ### Access below stack @%lx (sp=%lx)\n",
			       current->pid, ear0, __frame->sp);
			show_registers(__frame);
			printk("[%d] ### Code: [%08lx] %02x %02x %02x %02x %02x %02x %02x %02x\n",
			       current->pid,
			       __frame->pc,
			       ((u8*)__frame->pc)[0],
			       ((u8*)__frame->pc)[1],
			       ((u8*)__frame->pc)[2],
			       ((u8*)__frame->pc)[3],
			       ((u8*)__frame->pc)[4],
			       ((u8*)__frame->pc)[5],
			       ((u8*)__frame->pc)[6],
			       ((u8*)__frame->pc)[7]
			       );
#endif
			goto bad_area;
		}
	}

	if (expand_stack(vma, ear0))
		goto bad_area;

/*
 * Ok, we have a good vm_area for this memory access, so
 * we can handle it..
 */
 good_area:
	info.si_code = SEGV_ACCERR;
	write = 0;
	switch (esr0 & ESR0_ATXC) {
	default:
		/* handle write to write protected page */
	case ESR0_ATXC_WP_EXCEP:
#ifdef TEST_VERIFY_AREA
		if (!(user_mode(__frame)))
			printk("WP fault at %08lx\n", __frame->pc);
#endif
		if (!(vma->vm_flags & VM_WRITE))
			goto bad_area;
		write = 1;
		break;

		 /* handle read from protected page */
	case ESR0_ATXC_PRIV_EXCEP:
		goto bad_area;

		 /* handle read, write or exec on absent page
		  * - can't support write without permitting read
		  * - don't support execute without permitting read and vice-versa
		  */
	case ESR0_ATXC_AMRTLB_MISS:
		if (!(vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC)))
			goto bad_area;
		break;
	}

	/*
	 * 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, ear0, write)) {
	case VM_FAULT_MINOR:
		current->min_flt++;
		break;
	case VM_FAULT_MAJOR:
		current->maj_flt++;
		break;
	case VM_FAULT_SIGBUS:
		goto do_sigbus;
	default:
		goto out_of_memory;
	}

	up_read(&mm->mmap_sem);
	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:
	up_read(&mm->mmap_sem);

	/* User mode accesses just cause a SIGSEGV */
	if (user_mode(__frame)) {
		info.si_signo = SIGSEGV;
		info.si_errno = 0;
		/* info.si_code has been set above */
		info.si_addr = (void *) ear0;
		force_sig_info(SIGSEGV, &info, current);
		return;
	}

 no_context:
	/* are we prepared to handle this kernel fault? */
	if ((fixup = search_exception_table(__frame->pc)) != 0) {
		__frame->pc = fixup;
		return;
	}

/*
 * Oops. The kernel tried to access some bad page. We'll have to
 * terminate things with extreme prejudice.
 */

	bust_spinlocks(1);

	if (ear0 < PAGE_SIZE)
		printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");
	else
		printk(KERN_ALERT "Unable to handle kernel paging request");
	printk(" at virtual addr %08lx\n", ear0);
	printk("  PC  : %08lx\n", __frame->pc);
	printk("  EXC : esr0=%08lx ear0=%08lx\n", esr0, ear0);

	asm("lrai %1,%0,#1,#0,#0" : "=&r"(lrai) : "r"(ear0));
	asm("lrad %1,%0,#1,#0,#0" : "=&r"(lrad) : "r"(ear0));

	printk(KERN_ALERT "  LRAI: %08lx\n", lrai);
	printk(KERN_ALERT "  LRAD: %08lx\n", lrad);

	__break_hijack_kernel_event();

	pge = pgd_offset(current->mm, ear0);
	pue = pud_offset(pge, ear0);
	_pme = pue->pue[0].ste[0];

	printk(KERN_ALERT "  PGE : %8p { PME %08lx }\n", pge, _pme);

	if (_pme & xAMPRx_V) {
		unsigned long dampr, damlr, val;

		asm volatile("movsg dampr2,%0 ! movgs %2,dampr2 ! movsg damlr2,%1"
			     : "=&r"(dampr), "=r"(damlr)
			     : "r" (_pme | xAMPRx_L|xAMPRx_SS_16Kb|xAMPRx_S|xAMPRx_C|xAMPRx_V)
			     );

		pte = (pte_t *) damlr + __pte_index(ear0);
		val = pte_val(*pte);

		asm volatile("movgs %0,dampr2" :: "r" (dampr));

		printk(KERN_ALERT "  PTE : %8p { %08lx }\n", pte, val);
	}

	die_if_kernel("Oops\n");
	do_exit(SIGKILL);

/*
 * We ran out of memory, or some other thing happened to us that made
 * us unable to handle the page fault gracefully.
 */
 out_of_memory:
	up_read(&mm->mmap_sem);
	printk("VM: killing process %s\n", current->comm);
	if (user_mode(__frame))
		do_exit(SIGKILL);
	goto no_context;

 do_sigbus:
	up_read(&mm->mmap_sem);

	/*
	 * Send a sigbus, regardless of whether we were in kernel
	 * or user mode.
	 */
	info.si_signo = SIGBUS;
	info.si_errno = 0;
	info.si_code = BUS_ADRERR;
	info.si_addr = (void *) ear0;
	force_sig_info(SIGBUS, &info, current);

	/* Kernel mode? Handle exceptions or die */
	if (!user_mode(__frame))
		goto no_context;
	return;

/*
 * The fault was caused by a kernel PTE (such as installed by vmalloc or kmap)
 */
 kernel_pte_fault:
	{
		/*
		 * Synchronize this task's top level page-table
		 * with the 'reference' page table.
		 *
		 * Do _not_ use "tsk" here. We might be inside
		 * an interrupt in the middle of a task switch..
		 */
		int index = pgd_index(ear0);
		pgd_t *pgd, *pgd_k;
		pud_t *pud, *pud_k;
		pmd_t *pmd, *pmd_k;
		pte_t *pte_k;

		pgd = (pgd_t *) __get_TTBR();
		pgd = (pgd_t *)__va(pgd) + index;
		pgd_k = ((pgd_t *)(init_mm.pgd)) + index;

		if (!pgd_present(*pgd_k))
			goto no_context;
		//set_pgd(pgd, *pgd_k); /////// gcc ICE's on this line

		pud_k = pud_offset(pgd_k, ear0);
		if (!pud_present(*pud_k))
			goto no_context;

		pmd_k = pmd_offset(pud_k, ear0);
		if (!pmd_present(*pmd_k))
			goto no_context;

		pud = pud_offset(pgd, ear0);
		pmd = pmd_offset(pud, ear0);
		set_pmd(pmd, *pmd_k);

		pte_k = pte_offset_kernel(pmd_k, ear0);
		if (!pte_present(*pte_k))
			goto no_context;
		return;
	}
} /* end do_page_fault() */