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