Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/arch/frv/mm/fault.c | |
3 | * | |
4 | * Copyright (C) 2003 Red Hat, Inc. All Rights Reserved. | |
5 | * - Written by David Howells (dhowells@redhat.com) | |
6 | * - Derived from arch/m68knommu/mm/fault.c | |
7 | * - Copyright (C) 1998 D. Jeff Dionne <jeff@lineo.ca>, | |
8 | * - Copyright (C) 2000 Lineo, Inc. (www.lineo.com) | |
9 | * | |
10 | * Based on: | |
11 | * | |
12 | * linux/arch/m68k/mm/fault.c | |
13 | * | |
14 | * Copyright (C) 1995 Hamish Macdonald | |
15 | */ | |
16 | ||
17 | #include <linux/mman.h> | |
18 | #include <linux/mm.h> | |
19 | #include <linux/kernel.h> | |
20 | #include <linux/ptrace.h> | |
21 | #include <linux/hardirq.h> | |
70ffdb93 | 22 | #include <linux/uaccess.h> |
1da177e4 | 23 | |
1da177e4 | 24 | #include <asm/pgtable.h> |
1da177e4 LT |
25 | #include <asm/gdb-stub.h> |
26 | ||
27 | /*****************************************************************************/ | |
28 | /* | |
29 | * This routine handles page faults. It determines the problem, and | |
30 | * then passes it off to one of the appropriate routines. | |
31 | */ | |
32 | asmlinkage void do_page_fault(int datammu, unsigned long esr0, unsigned long ear0) | |
33 | { | |
34 | struct vm_area_struct *vma; | |
35 | struct mm_struct *mm; | |
36 | unsigned long _pme, lrai, lrad, fixup; | |
759496ba | 37 | unsigned long flags = 0; |
1da177e4 LT |
38 | siginfo_t info; |
39 | pgd_t *pge; | |
40 | pud_t *pue; | |
41 | pte_t *pte; | |
83c54070 | 42 | int fault; |
1da177e4 LT |
43 | |
44 | #if 0 | |
45 | const char *atxc[16] = { | |
46 | [0x0] = "mmu-miss", [0x8] = "multi-dat", [0x9] = "multi-sat", | |
47 | [0xa] = "tlb-miss", [0xc] = "privilege", [0xd] = "write-prot", | |
48 | }; | |
49 | ||
50 | printk("do_page_fault(%d,%lx [%s],%lx)\n", | |
51 | datammu, esr0, atxc[esr0 >> 20 & 0xf], ear0); | |
52 | #endif | |
53 | ||
54 | mm = current->mm; | |
55 | ||
56 | /* | |
57 | * We fault-in kernel-space virtual memory on-demand. The | |
58 | * 'reference' page table is init_mm.pgd. | |
59 | * | |
60 | * NOTE! We MUST NOT take any locks for this case. We may | |
61 | * be in an interrupt or a critical region, and should | |
62 | * only copy the information from the master page table, | |
63 | * nothing more. | |
64 | * | |
65 | * This verifies that the fault happens in kernel space | |
66 | * and that the fault was a page not present (invalid) error | |
67 | */ | |
68 | if (!user_mode(__frame) && (esr0 & ESR0_ATXC) == ESR0_ATXC_AMRTLB_MISS) { | |
69 | if (ear0 >= VMALLOC_START && ear0 < VMALLOC_END) | |
70 | goto kernel_pte_fault; | |
71 | if (ear0 >= PKMAP_BASE && ear0 < PKMAP_END) | |
72 | goto kernel_pte_fault; | |
73 | } | |
74 | ||
75 | info.si_code = SEGV_MAPERR; | |
76 | ||
77 | /* | |
78 | * If we're in an interrupt or have no user | |
79 | * context, we must not take the fault.. | |
80 | */ | |
70ffdb93 | 81 | if (faulthandler_disabled() || !mm) |
1da177e4 LT |
82 | goto no_context; |
83 | ||
759496ba JW |
84 | if (user_mode(__frame)) |
85 | flags |= FAULT_FLAG_USER; | |
86 | ||
1da177e4 LT |
87 | down_read(&mm->mmap_sem); |
88 | ||
89 | vma = find_vma(mm, ear0); | |
90 | if (!vma) | |
91 | goto bad_area; | |
92 | if (vma->vm_start <= ear0) | |
93 | goto good_area; | |
94 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
95 | goto bad_area; | |
96 | ||
97 | if (user_mode(__frame)) { | |
98 | /* | |
99 | * accessing the stack below %esp is always a bug. | |
100 | * The "+ 32" is there due to some instructions (like | |
101 | * pusha) doing post-decrement on the stack and that | |
102 | * doesn't show up until later.. | |
103 | */ | |
104 | if ((ear0 & PAGE_MASK) + 2 * PAGE_SIZE < __frame->sp) { | |
105 | #if 0 | |
106 | printk("[%d] ### Access below stack @%lx (sp=%lx)\n", | |
107 | current->pid, ear0, __frame->sp); | |
108 | show_registers(__frame); | |
109 | printk("[%d] ### Code: [%08lx] %02x %02x %02x %02x %02x %02x %02x %02x\n", | |
110 | current->pid, | |
111 | __frame->pc, | |
112 | ((u8*)__frame->pc)[0], | |
113 | ((u8*)__frame->pc)[1], | |
114 | ((u8*)__frame->pc)[2], | |
115 | ((u8*)__frame->pc)[3], | |
116 | ((u8*)__frame->pc)[4], | |
117 | ((u8*)__frame->pc)[5], | |
118 | ((u8*)__frame->pc)[6], | |
119 | ((u8*)__frame->pc)[7] | |
120 | ); | |
121 | #endif | |
122 | goto bad_area; | |
123 | } | |
124 | } | |
125 | ||
126 | if (expand_stack(vma, ear0)) | |
127 | goto bad_area; | |
128 | ||
129 | /* | |
130 | * Ok, we have a good vm_area for this memory access, so | |
131 | * we can handle it.. | |
132 | */ | |
133 | good_area: | |
134 | info.si_code = SEGV_ACCERR; | |
1da177e4 LT |
135 | switch (esr0 & ESR0_ATXC) { |
136 | default: | |
137 | /* handle write to write protected page */ | |
138 | case ESR0_ATXC_WP_EXCEP: | |
139 | #ifdef TEST_VERIFY_AREA | |
140 | if (!(user_mode(__frame))) | |
141 | printk("WP fault at %08lx\n", __frame->pc); | |
142 | #endif | |
143 | if (!(vma->vm_flags & VM_WRITE)) | |
144 | goto bad_area; | |
759496ba | 145 | flags |= FAULT_FLAG_WRITE; |
1da177e4 LT |
146 | break; |
147 | ||
148 | /* handle read from protected page */ | |
149 | case ESR0_ATXC_PRIV_EXCEP: | |
150 | goto bad_area; | |
151 | ||
152 | /* handle read, write or exec on absent page | |
153 | * - can't support write without permitting read | |
154 | * - don't support execute without permitting read and vice-versa | |
155 | */ | |
156 | case ESR0_ATXC_AMRTLB_MISS: | |
157 | if (!(vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC))) | |
158 | goto bad_area; | |
159 | break; | |
160 | } | |
161 | ||
162 | /* | |
163 | * If for any reason at all we couldn't handle the fault, | |
164 | * make sure we exit gracefully rather than endlessly redo | |
165 | * the fault. | |
166 | */ | |
759496ba | 167 | fault = handle_mm_fault(mm, vma, ear0, flags); |
83c54070 NP |
168 | if (unlikely(fault & VM_FAULT_ERROR)) { |
169 | if (fault & VM_FAULT_OOM) | |
170 | goto out_of_memory; | |
33692f27 LT |
171 | else if (fault & VM_FAULT_SIGSEGV) |
172 | goto bad_area; | |
83c54070 NP |
173 | else if (fault & VM_FAULT_SIGBUS) |
174 | goto do_sigbus; | |
175 | BUG(); | |
1da177e4 | 176 | } |
83c54070 NP |
177 | if (fault & VM_FAULT_MAJOR) |
178 | current->maj_flt++; | |
179 | else | |
180 | current->min_flt++; | |
1da177e4 LT |
181 | |
182 | up_read(&mm->mmap_sem); | |
183 | return; | |
184 | ||
185 | /* | |
186 | * Something tried to access memory that isn't in our memory map.. | |
187 | * Fix it, but check if it's kernel or user first.. | |
188 | */ | |
189 | bad_area: | |
190 | up_read(&mm->mmap_sem); | |
191 | ||
192 | /* User mode accesses just cause a SIGSEGV */ | |
193 | if (user_mode(__frame)) { | |
194 | info.si_signo = SIGSEGV; | |
195 | info.si_errno = 0; | |
196 | /* info.si_code has been set above */ | |
197 | info.si_addr = (void *) ear0; | |
198 | force_sig_info(SIGSEGV, &info, current); | |
199 | return; | |
200 | } | |
201 | ||
202 | no_context: | |
203 | /* are we prepared to handle this kernel fault? */ | |
204 | if ((fixup = search_exception_table(__frame->pc)) != 0) { | |
205 | __frame->pc = fixup; | |
206 | return; | |
207 | } | |
208 | ||
209 | /* | |
210 | * Oops. The kernel tried to access some bad page. We'll have to | |
211 | * terminate things with extreme prejudice. | |
212 | */ | |
213 | ||
214 | bust_spinlocks(1); | |
215 | ||
216 | if (ear0 < PAGE_SIZE) | |
217 | printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference"); | |
218 | else | |
219 | printk(KERN_ALERT "Unable to handle kernel paging request"); | |
220 | printk(" at virtual addr %08lx\n", ear0); | |
221 | printk(" PC : %08lx\n", __frame->pc); | |
222 | printk(" EXC : esr0=%08lx ear0=%08lx\n", esr0, ear0); | |
223 | ||
224 | asm("lrai %1,%0,#1,#0,#0" : "=&r"(lrai) : "r"(ear0)); | |
225 | asm("lrad %1,%0,#1,#0,#0" : "=&r"(lrad) : "r"(ear0)); | |
226 | ||
227 | printk(KERN_ALERT " LRAI: %08lx\n", lrai); | |
228 | printk(KERN_ALERT " LRAD: %08lx\n", lrad); | |
229 | ||
230 | __break_hijack_kernel_event(); | |
231 | ||
232 | pge = pgd_offset(current->mm, ear0); | |
233 | pue = pud_offset(pge, ear0); | |
234 | _pme = pue->pue[0].ste[0]; | |
235 | ||
236 | printk(KERN_ALERT " PGE : %8p { PME %08lx }\n", pge, _pme); | |
237 | ||
238 | if (_pme & xAMPRx_V) { | |
239 | unsigned long dampr, damlr, val; | |
240 | ||
241 | asm volatile("movsg dampr2,%0 ! movgs %2,dampr2 ! movsg damlr2,%1" | |
242 | : "=&r"(dampr), "=r"(damlr) | |
243 | : "r" (_pme | xAMPRx_L|xAMPRx_SS_16Kb|xAMPRx_S|xAMPRx_C|xAMPRx_V) | |
244 | ); | |
245 | ||
246 | pte = (pte_t *) damlr + __pte_index(ear0); | |
247 | val = pte_val(*pte); | |
248 | ||
249 | asm volatile("movgs %0,dampr2" :: "r" (dampr)); | |
250 | ||
251 | printk(KERN_ALERT " PTE : %8p { %08lx }\n", pte, val); | |
252 | } | |
253 | ||
254 | die_if_kernel("Oops\n"); | |
255 | do_exit(SIGKILL); | |
256 | ||
257 | /* | |
258 | * We ran out of memory, or some other thing happened to us that made | |
259 | * us unable to handle the page fault gracefully. | |
260 | */ | |
261 | out_of_memory: | |
262 | up_read(&mm->mmap_sem); | |
f9c497c4 NP |
263 | if (!user_mode(__frame)) |
264 | goto no_context; | |
265 | pagefault_out_of_memory(); | |
266 | return; | |
1da177e4 LT |
267 | |
268 | do_sigbus: | |
269 | up_read(&mm->mmap_sem); | |
270 | ||
271 | /* | |
272 | * Send a sigbus, regardless of whether we were in kernel | |
273 | * or user mode. | |
274 | */ | |
275 | info.si_signo = SIGBUS; | |
276 | info.si_errno = 0; | |
277 | info.si_code = BUS_ADRERR; | |
278 | info.si_addr = (void *) ear0; | |
279 | force_sig_info(SIGBUS, &info, current); | |
280 | ||
281 | /* Kernel mode? Handle exceptions or die */ | |
282 | if (!user_mode(__frame)) | |
283 | goto no_context; | |
284 | return; | |
285 | ||
286 | /* | |
287 | * The fault was caused by a kernel PTE (such as installed by vmalloc or kmap) | |
288 | */ | |
289 | kernel_pte_fault: | |
290 | { | |
291 | /* | |
292 | * Synchronize this task's top level page-table | |
293 | * with the 'reference' page table. | |
294 | * | |
295 | * Do _not_ use "tsk" here. We might be inside | |
296 | * an interrupt in the middle of a task switch.. | |
297 | */ | |
298 | int index = pgd_index(ear0); | |
299 | pgd_t *pgd, *pgd_k; | |
300 | pud_t *pud, *pud_k; | |
301 | pmd_t *pmd, *pmd_k; | |
302 | pte_t *pte_k; | |
303 | ||
304 | pgd = (pgd_t *) __get_TTBR(); | |
305 | pgd = (pgd_t *)__va(pgd) + index; | |
306 | pgd_k = ((pgd_t *)(init_mm.pgd)) + index; | |
307 | ||
308 | if (!pgd_present(*pgd_k)) | |
309 | goto no_context; | |
310 | //set_pgd(pgd, *pgd_k); /////// gcc ICE's on this line | |
311 | ||
312 | pud_k = pud_offset(pgd_k, ear0); | |
313 | if (!pud_present(*pud_k)) | |
314 | goto no_context; | |
315 | ||
316 | pmd_k = pmd_offset(pud_k, ear0); | |
317 | if (!pmd_present(*pmd_k)) | |
318 | goto no_context; | |
319 | ||
320 | pud = pud_offset(pgd, ear0); | |
321 | pmd = pmd_offset(pud, ear0); | |
322 | set_pmd(pmd, *pmd_k); | |
323 | ||
324 | pte_k = pte_offset_kernel(pmd_k, ear0); | |
325 | if (!pte_present(*pte_k)) | |
326 | goto no_context; | |
327 | return; | |
328 | } | |
329 | } /* end do_page_fault() */ |