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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> | |
22 | ||
23 | #include <asm/system.h> | |
24 | #include <asm/pgtable.h> | |
25 | #include <asm/uaccess.h> | |
26 | #include <asm/gdb-stub.h> | |
27 | ||
28 | /*****************************************************************************/ | |
29 | /* | |
30 | * This routine handles page faults. It determines the problem, and | |
31 | * then passes it off to one of the appropriate routines. | |
32 | */ | |
33 | asmlinkage void do_page_fault(int datammu, unsigned long esr0, unsigned long ear0) | |
34 | { | |
35 | struct vm_area_struct *vma; | |
36 | struct mm_struct *mm; | |
37 | unsigned long _pme, lrai, lrad, fixup; | |
38 | siginfo_t info; | |
39 | pgd_t *pge; | |
40 | pud_t *pue; | |
41 | pte_t *pte; | |
42 | int write; | |
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 | */ | |
6edaf68a | 81 | if (in_atomic() || !mm) |
1da177e4 LT |
82 | goto no_context; |
83 | ||
84 | down_read(&mm->mmap_sem); | |
85 | ||
86 | vma = find_vma(mm, ear0); | |
87 | if (!vma) | |
88 | goto bad_area; | |
89 | if (vma->vm_start <= ear0) | |
90 | goto good_area; | |
91 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
92 | goto bad_area; | |
93 | ||
94 | if (user_mode(__frame)) { | |
95 | /* | |
96 | * accessing the stack below %esp is always a bug. | |
97 | * The "+ 32" is there due to some instructions (like | |
98 | * pusha) doing post-decrement on the stack and that | |
99 | * doesn't show up until later.. | |
100 | */ | |
101 | if ((ear0 & PAGE_MASK) + 2 * PAGE_SIZE < __frame->sp) { | |
102 | #if 0 | |
103 | printk("[%d] ### Access below stack @%lx (sp=%lx)\n", | |
104 | current->pid, ear0, __frame->sp); | |
105 | show_registers(__frame); | |
106 | printk("[%d] ### Code: [%08lx] %02x %02x %02x %02x %02x %02x %02x %02x\n", | |
107 | current->pid, | |
108 | __frame->pc, | |
109 | ((u8*)__frame->pc)[0], | |
110 | ((u8*)__frame->pc)[1], | |
111 | ((u8*)__frame->pc)[2], | |
112 | ((u8*)__frame->pc)[3], | |
113 | ((u8*)__frame->pc)[4], | |
114 | ((u8*)__frame->pc)[5], | |
115 | ((u8*)__frame->pc)[6], | |
116 | ((u8*)__frame->pc)[7] | |
117 | ); | |
118 | #endif | |
119 | goto bad_area; | |
120 | } | |
121 | } | |
122 | ||
123 | if (expand_stack(vma, ear0)) | |
124 | goto bad_area; | |
125 | ||
126 | /* | |
127 | * Ok, we have a good vm_area for this memory access, so | |
128 | * we can handle it.. | |
129 | */ | |
130 | good_area: | |
131 | info.si_code = SEGV_ACCERR; | |
132 | write = 0; | |
133 | switch (esr0 & ESR0_ATXC) { | |
134 | default: | |
135 | /* handle write to write protected page */ | |
136 | case ESR0_ATXC_WP_EXCEP: | |
137 | #ifdef TEST_VERIFY_AREA | |
138 | if (!(user_mode(__frame))) | |
139 | printk("WP fault at %08lx\n", __frame->pc); | |
140 | #endif | |
141 | if (!(vma->vm_flags & VM_WRITE)) | |
142 | goto bad_area; | |
143 | write = 1; | |
144 | break; | |
145 | ||
146 | /* handle read from protected page */ | |
147 | case ESR0_ATXC_PRIV_EXCEP: | |
148 | goto bad_area; | |
149 | ||
150 | /* handle read, write or exec on absent page | |
151 | * - can't support write without permitting read | |
152 | * - don't support execute without permitting read and vice-versa | |
153 | */ | |
154 | case ESR0_ATXC_AMRTLB_MISS: | |
155 | if (!(vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC))) | |
156 | goto bad_area; | |
157 | break; | |
158 | } | |
159 | ||
160 | /* | |
161 | * If for any reason at all we couldn't handle the fault, | |
162 | * make sure we exit gracefully rather than endlessly redo | |
163 | * the fault. | |
164 | */ | |
165 | switch (handle_mm_fault(mm, vma, ear0, write)) { | |
6e346228 | 166 | case VM_FAULT_MINOR: |
1da177e4 LT |
167 | current->min_flt++; |
168 | break; | |
6e346228 | 169 | case VM_FAULT_MAJOR: |
1da177e4 LT |
170 | current->maj_flt++; |
171 | break; | |
6e346228 | 172 | case VM_FAULT_SIGBUS: |
1da177e4 LT |
173 | goto do_sigbus; |
174 | default: | |
175 | goto out_of_memory; | |
176 | } | |
177 | ||
178 | up_read(&mm->mmap_sem); | |
179 | return; | |
180 | ||
181 | /* | |
182 | * Something tried to access memory that isn't in our memory map.. | |
183 | * Fix it, but check if it's kernel or user first.. | |
184 | */ | |
185 | bad_area: | |
186 | up_read(&mm->mmap_sem); | |
187 | ||
188 | /* User mode accesses just cause a SIGSEGV */ | |
189 | if (user_mode(__frame)) { | |
190 | info.si_signo = SIGSEGV; | |
191 | info.si_errno = 0; | |
192 | /* info.si_code has been set above */ | |
193 | info.si_addr = (void *) ear0; | |
194 | force_sig_info(SIGSEGV, &info, current); | |
195 | return; | |
196 | } | |
197 | ||
198 | no_context: | |
199 | /* are we prepared to handle this kernel fault? */ | |
200 | if ((fixup = search_exception_table(__frame->pc)) != 0) { | |
201 | __frame->pc = fixup; | |
202 | return; | |
203 | } | |
204 | ||
205 | /* | |
206 | * Oops. The kernel tried to access some bad page. We'll have to | |
207 | * terminate things with extreme prejudice. | |
208 | */ | |
209 | ||
210 | bust_spinlocks(1); | |
211 | ||
212 | if (ear0 < PAGE_SIZE) | |
213 | printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference"); | |
214 | else | |
215 | printk(KERN_ALERT "Unable to handle kernel paging request"); | |
216 | printk(" at virtual addr %08lx\n", ear0); | |
217 | printk(" PC : %08lx\n", __frame->pc); | |
218 | printk(" EXC : esr0=%08lx ear0=%08lx\n", esr0, ear0); | |
219 | ||
220 | asm("lrai %1,%0,#1,#0,#0" : "=&r"(lrai) : "r"(ear0)); | |
221 | asm("lrad %1,%0,#1,#0,#0" : "=&r"(lrad) : "r"(ear0)); | |
222 | ||
223 | printk(KERN_ALERT " LRAI: %08lx\n", lrai); | |
224 | printk(KERN_ALERT " LRAD: %08lx\n", lrad); | |
225 | ||
226 | __break_hijack_kernel_event(); | |
227 | ||
228 | pge = pgd_offset(current->mm, ear0); | |
229 | pue = pud_offset(pge, ear0); | |
230 | _pme = pue->pue[0].ste[0]; | |
231 | ||
232 | printk(KERN_ALERT " PGE : %8p { PME %08lx }\n", pge, _pme); | |
233 | ||
234 | if (_pme & xAMPRx_V) { | |
235 | unsigned long dampr, damlr, val; | |
236 | ||
237 | asm volatile("movsg dampr2,%0 ! movgs %2,dampr2 ! movsg damlr2,%1" | |
238 | : "=&r"(dampr), "=r"(damlr) | |
239 | : "r" (_pme | xAMPRx_L|xAMPRx_SS_16Kb|xAMPRx_S|xAMPRx_C|xAMPRx_V) | |
240 | ); | |
241 | ||
242 | pte = (pte_t *) damlr + __pte_index(ear0); | |
243 | val = pte_val(*pte); | |
244 | ||
245 | asm volatile("movgs %0,dampr2" :: "r" (dampr)); | |
246 | ||
247 | printk(KERN_ALERT " PTE : %8p { %08lx }\n", pte, val); | |
248 | } | |
249 | ||
250 | die_if_kernel("Oops\n"); | |
251 | do_exit(SIGKILL); | |
252 | ||
253 | /* | |
254 | * We ran out of memory, or some other thing happened to us that made | |
255 | * us unable to handle the page fault gracefully. | |
256 | */ | |
257 | out_of_memory: | |
258 | up_read(&mm->mmap_sem); | |
259 | printk("VM: killing process %s\n", current->comm); | |
260 | if (user_mode(__frame)) | |
261 | do_exit(SIGKILL); | |
262 | goto no_context; | |
263 | ||
264 | do_sigbus: | |
265 | up_read(&mm->mmap_sem); | |
266 | ||
267 | /* | |
268 | * Send a sigbus, regardless of whether we were in kernel | |
269 | * or user mode. | |
270 | */ | |
271 | info.si_signo = SIGBUS; | |
272 | info.si_errno = 0; | |
273 | info.si_code = BUS_ADRERR; | |
274 | info.si_addr = (void *) ear0; | |
275 | force_sig_info(SIGBUS, &info, current); | |
276 | ||
277 | /* Kernel mode? Handle exceptions or die */ | |
278 | if (!user_mode(__frame)) | |
279 | goto no_context; | |
280 | return; | |
281 | ||
282 | /* | |
283 | * The fault was caused by a kernel PTE (such as installed by vmalloc or kmap) | |
284 | */ | |
285 | kernel_pte_fault: | |
286 | { | |
287 | /* | |
288 | * Synchronize this task's top level page-table | |
289 | * with the 'reference' page table. | |
290 | * | |
291 | * Do _not_ use "tsk" here. We might be inside | |
292 | * an interrupt in the middle of a task switch.. | |
293 | */ | |
294 | int index = pgd_index(ear0); | |
295 | pgd_t *pgd, *pgd_k; | |
296 | pud_t *pud, *pud_k; | |
297 | pmd_t *pmd, *pmd_k; | |
298 | pte_t *pte_k; | |
299 | ||
300 | pgd = (pgd_t *) __get_TTBR(); | |
301 | pgd = (pgd_t *)__va(pgd) + index; | |
302 | pgd_k = ((pgd_t *)(init_mm.pgd)) + index; | |
303 | ||
304 | if (!pgd_present(*pgd_k)) | |
305 | goto no_context; | |
306 | //set_pgd(pgd, *pgd_k); /////// gcc ICE's on this line | |
307 | ||
308 | pud_k = pud_offset(pgd_k, ear0); | |
309 | if (!pud_present(*pud_k)) | |
310 | goto no_context; | |
311 | ||
312 | pmd_k = pmd_offset(pud_k, ear0); | |
313 | if (!pmd_present(*pmd_k)) | |
314 | goto no_context; | |
315 | ||
316 | pud = pud_offset(pgd, ear0); | |
317 | pmd = pmd_offset(pud, ear0); | |
318 | set_pmd(pmd, *pmd_k); | |
319 | ||
320 | pte_k = pte_offset_kernel(pmd_k, ear0); | |
321 | if (!pte_present(*pte_k)) | |
322 | goto no_context; | |
323 | return; | |
324 | } | |
325 | } /* end do_page_fault() */ |