Paul Mackerras | 14cf11a | 2005-09-26 16:04:21 +1000 | [diff] [blame] | 1 | /* |
Paul Mackerras | 14cf11a | 2005-09-26 16:04:21 +1000 | [diff] [blame] | 2 | * PowerPC version |
| 3 | * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) |
| 4 | * |
| 5 | * Derived from "arch/i386/mm/fault.c" |
| 6 | * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds |
| 7 | * |
| 8 | * Modified by Cort Dougan and Paul Mackerras. |
| 9 | * |
| 10 | * Modified for PPC64 by Dave Engebretsen (engebret@ibm.com) |
| 11 | * |
| 12 | * This program is free software; you can redistribute it and/or |
| 13 | * modify it under the terms of the GNU General Public License |
| 14 | * as published by the Free Software Foundation; either version |
| 15 | * 2 of the License, or (at your option) any later version. |
| 16 | */ |
| 17 | |
Paul Mackerras | 14cf11a | 2005-09-26 16:04:21 +1000 | [diff] [blame] | 18 | #include <linux/signal.h> |
| 19 | #include <linux/sched.h> |
| 20 | #include <linux/kernel.h> |
| 21 | #include <linux/errno.h> |
| 22 | #include <linux/string.h> |
| 23 | #include <linux/types.h> |
| 24 | #include <linux/ptrace.h> |
| 25 | #include <linux/mman.h> |
| 26 | #include <linux/mm.h> |
| 27 | #include <linux/interrupt.h> |
| 28 | #include <linux/highmem.h> |
| 29 | #include <linux/module.h> |
| 30 | #include <linux/kprobes.h> |
Christoph Hellwig | 1eeb66a | 2007-05-08 00:27:03 -0700 | [diff] [blame] | 31 | #include <linux/kdebug.h> |
Paul Mackerras | 14cf11a | 2005-09-26 16:04:21 +1000 | [diff] [blame] | 32 | |
| 33 | #include <asm/page.h> |
| 34 | #include <asm/pgtable.h> |
| 35 | #include <asm/mmu.h> |
| 36 | #include <asm/mmu_context.h> |
| 37 | #include <asm/system.h> |
| 38 | #include <asm/uaccess.h> |
| 39 | #include <asm/tlbflush.h> |
Paul Mackerras | 14cf11a | 2005-09-26 16:04:21 +1000 | [diff] [blame] | 40 | #include <asm/siginfo.h> |
| 41 | |
Christoph Hellwig | 9f90b99 | 2007-04-30 11:56:46 +0100 | [diff] [blame] | 42 | |
Anil S Keshavamurthy | 4f9e87c | 2006-06-26 00:25:27 -0700 | [diff] [blame] | 43 | #ifdef CONFIG_KPROBES |
Christoph Hellwig | 9f90b99 | 2007-04-30 11:56:46 +0100 | [diff] [blame] | 44 | static inline int notify_page_fault(struct pt_regs *regs) |
Anil S Keshavamurthy | 4f9e87c | 2006-06-26 00:25:27 -0700 | [diff] [blame] | 45 | { |
Christoph Hellwig | 9f90b99 | 2007-04-30 11:56:46 +0100 | [diff] [blame] | 46 | int ret = 0; |
Anil S Keshavamurthy | 4f9e87c | 2006-06-26 00:25:27 -0700 | [diff] [blame] | 47 | |
Christoph Hellwig | 9f90b99 | 2007-04-30 11:56:46 +0100 | [diff] [blame] | 48 | /* kprobe_running() needs smp_processor_id() */ |
| 49 | if (!user_mode(regs)) { |
| 50 | preempt_disable(); |
| 51 | if (kprobe_running() && kprobe_fault_handler(regs, 11)) |
| 52 | ret = 1; |
| 53 | preempt_enable(); |
| 54 | } |
Anil S Keshavamurthy | 4f9e87c | 2006-06-26 00:25:27 -0700 | [diff] [blame] | 55 | |
Christoph Hellwig | 9f90b99 | 2007-04-30 11:56:46 +0100 | [diff] [blame] | 56 | return ret; |
Anil S Keshavamurthy | 4f9e87c | 2006-06-26 00:25:27 -0700 | [diff] [blame] | 57 | } |
| 58 | #else |
Christoph Hellwig | 9f90b99 | 2007-04-30 11:56:46 +0100 | [diff] [blame] | 59 | static inline int notify_page_fault(struct pt_regs *regs) |
Anil S Keshavamurthy | 4f9e87c | 2006-06-26 00:25:27 -0700 | [diff] [blame] | 60 | { |
Christoph Hellwig | 9f90b99 | 2007-04-30 11:56:46 +0100 | [diff] [blame] | 61 | return 0; |
Anil S Keshavamurthy | 4f9e87c | 2006-06-26 00:25:27 -0700 | [diff] [blame] | 62 | } |
| 63 | #endif |
| 64 | |
Paul Mackerras | 14cf11a | 2005-09-26 16:04:21 +1000 | [diff] [blame] | 65 | /* |
| 66 | * Check whether the instruction at regs->nip is a store using |
| 67 | * an update addressing form which will update r1. |
| 68 | */ |
| 69 | static int store_updates_sp(struct pt_regs *regs) |
| 70 | { |
| 71 | unsigned int inst; |
| 72 | |
| 73 | if (get_user(inst, (unsigned int __user *)regs->nip)) |
| 74 | return 0; |
| 75 | /* check for 1 in the rA field */ |
| 76 | if (((inst >> 16) & 0x1f) != 1) |
| 77 | return 0; |
| 78 | /* check major opcode */ |
| 79 | switch (inst >> 26) { |
| 80 | case 37: /* stwu */ |
| 81 | case 39: /* stbu */ |
| 82 | case 45: /* sthu */ |
| 83 | case 53: /* stfsu */ |
| 84 | case 55: /* stfdu */ |
| 85 | return 1; |
| 86 | case 62: /* std or stdu */ |
| 87 | return (inst & 3) == 1; |
| 88 | case 31: |
| 89 | /* check minor opcode */ |
| 90 | switch ((inst >> 1) & 0x3ff) { |
| 91 | case 181: /* stdux */ |
| 92 | case 183: /* stwux */ |
| 93 | case 247: /* stbux */ |
| 94 | case 439: /* sthux */ |
| 95 | case 695: /* stfsux */ |
| 96 | case 759: /* stfdux */ |
| 97 | return 1; |
| 98 | } |
| 99 | } |
| 100 | return 0; |
| 101 | } |
| 102 | |
Kumar Gala | cffb09c | 2005-10-26 09:55:41 -0500 | [diff] [blame] | 103 | #if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE)) |
Anton Blanchard | bce6c5f | 2006-01-09 15:47:04 +1100 | [diff] [blame] | 104 | static void do_dabr(struct pt_regs *regs, unsigned long address, |
| 105 | unsigned long error_code) |
Paul Mackerras | 14cf11a | 2005-09-26 16:04:21 +1000 | [diff] [blame] | 106 | { |
| 107 | siginfo_t info; |
| 108 | |
| 109 | if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code, |
| 110 | 11, SIGSEGV) == NOTIFY_STOP) |
| 111 | return; |
| 112 | |
| 113 | if (debugger_dabr_match(regs)) |
| 114 | return; |
| 115 | |
| 116 | /* Clear the DABR */ |
| 117 | set_dabr(0); |
| 118 | |
| 119 | /* Deliver the signal to userspace */ |
| 120 | info.si_signo = SIGTRAP; |
| 121 | info.si_errno = 0; |
| 122 | info.si_code = TRAP_HWBKPT; |
Anton Blanchard | bce6c5f | 2006-01-09 15:47:04 +1100 | [diff] [blame] | 123 | info.si_addr = (void __user *)address; |
Paul Mackerras | 14cf11a | 2005-09-26 16:04:21 +1000 | [diff] [blame] | 124 | force_sig_info(SIGTRAP, &info, current); |
| 125 | } |
Kumar Gala | cffb09c | 2005-10-26 09:55:41 -0500 | [diff] [blame] | 126 | #endif /* !(CONFIG_4xx || CONFIG_BOOKE)*/ |
Paul Mackerras | 14cf11a | 2005-09-26 16:04:21 +1000 | [diff] [blame] | 127 | |
| 128 | /* |
| 129 | * For 600- and 800-family processors, the error_code parameter is DSISR |
| 130 | * for a data fault, SRR1 for an instruction fault. For 400-family processors |
| 131 | * the error_code parameter is ESR for a data fault, 0 for an instruction |
| 132 | * fault. |
| 133 | * For 64-bit processors, the error_code parameter is |
| 134 | * - DSISR for a non-SLB data access fault, |
| 135 | * - SRR1 & 0x08000000 for a non-SLB instruction access fault |
| 136 | * - 0 any SLB fault. |
| 137 | * |
| 138 | * The return value is 0 if the fault was handled, or the signal |
| 139 | * number if this is a kernel fault that can't be handled here. |
| 140 | */ |
| 141 | int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address, |
| 142 | unsigned long error_code) |
| 143 | { |
| 144 | struct vm_area_struct * vma; |
| 145 | struct mm_struct *mm = current->mm; |
| 146 | siginfo_t info; |
| 147 | int code = SEGV_MAPERR; |
Nick Piggin | 83c5407 | 2007-07-19 01:47:05 -0700 | [diff] [blame] | 148 | int is_write = 0, ret; |
Paul Mackerras | 14cf11a | 2005-09-26 16:04:21 +1000 | [diff] [blame] | 149 | int trap = TRAP(regs); |
| 150 | int is_exec = trap == 0x400; |
| 151 | |
| 152 | #if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE)) |
| 153 | /* |
| 154 | * Fortunately the bit assignments in SRR1 for an instruction |
| 155 | * fault and DSISR for a data fault are mostly the same for the |
| 156 | * bits we are interested in. But there are some bits which |
| 157 | * indicate errors in DSISR but can validly be set in SRR1. |
| 158 | */ |
| 159 | if (trap == 0x400) |
| 160 | error_code &= 0x48200000; |
| 161 | else |
| 162 | is_write = error_code & DSISR_ISSTORE; |
| 163 | #else |
| 164 | is_write = error_code & ESR_DST; |
| 165 | #endif /* CONFIG_4xx || CONFIG_BOOKE */ |
| 166 | |
Christoph Hellwig | 9f90b99 | 2007-04-30 11:56:46 +0100 | [diff] [blame] | 167 | if (notify_page_fault(regs)) |
Paul Mackerras | 14cf11a | 2005-09-26 16:04:21 +1000 | [diff] [blame] | 168 | return 0; |
| 169 | |
| 170 | if (trap == 0x300) { |
| 171 | if (debugger_fault_handler(regs)) |
| 172 | return 0; |
| 173 | } |
| 174 | |
| 175 | /* On a kernel SLB miss we can only check for a valid exception entry */ |
| 176 | if (!user_mode(regs) && (address >= TASK_SIZE)) |
| 177 | return SIGSEGV; |
| 178 | |
| 179 | #if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE)) |
| 180 | if (error_code & DSISR_DABRMATCH) { |
| 181 | /* DABR match */ |
Anton Blanchard | bce6c5f | 2006-01-09 15:47:04 +1100 | [diff] [blame] | 182 | do_dabr(regs, address, error_code); |
Paul Mackerras | 14cf11a | 2005-09-26 16:04:21 +1000 | [diff] [blame] | 183 | return 0; |
| 184 | } |
| 185 | #endif /* !(CONFIG_4xx || CONFIG_BOOKE)*/ |
| 186 | |
| 187 | if (in_atomic() || mm == NULL) { |
| 188 | if (!user_mode(regs)) |
| 189 | return SIGSEGV; |
| 190 | /* in_atomic() in user mode is really bad, |
| 191 | as is current->mm == NULL. */ |
| 192 | printk(KERN_EMERG "Page fault in user mode with" |
| 193 | "in_atomic() = %d mm = %p\n", in_atomic(), mm); |
| 194 | printk(KERN_EMERG "NIP = %lx MSR = %lx\n", |
| 195 | regs->nip, regs->msr); |
| 196 | die("Weird page fault", regs, SIGSEGV); |
| 197 | } |
| 198 | |
| 199 | /* When running in the kernel we expect faults to occur only to |
| 200 | * addresses in user space. All other faults represent errors in the |
Anton Blanchard | fc5266e | 2006-04-01 11:33:12 +1100 | [diff] [blame] | 201 | * kernel and should generate an OOPS. Unfortunately, in the case of an |
| 202 | * erroneous fault occurring in a code path which already holds mmap_sem |
Paul Mackerras | 14cf11a | 2005-09-26 16:04:21 +1000 | [diff] [blame] | 203 | * we will deadlock attempting to validate the fault against the |
| 204 | * address space. Luckily the kernel only validly references user |
| 205 | * space from well defined areas of code, which are listed in the |
| 206 | * exceptions table. |
| 207 | * |
| 208 | * As the vast majority of faults will be valid we will only perform |
Anton Blanchard | fc5266e | 2006-04-01 11:33:12 +1100 | [diff] [blame] | 209 | * the source reference check when there is a possibility of a deadlock. |
Paul Mackerras | 14cf11a | 2005-09-26 16:04:21 +1000 | [diff] [blame] | 210 | * Attempt to lock the address space, if we cannot we then validate the |
| 211 | * source. If this is invalid we can skip the address space check, |
| 212 | * thus avoiding the deadlock. |
| 213 | */ |
| 214 | if (!down_read_trylock(&mm->mmap_sem)) { |
| 215 | if (!user_mode(regs) && !search_exception_tables(regs->nip)) |
| 216 | goto bad_area_nosemaphore; |
| 217 | |
| 218 | down_read(&mm->mmap_sem); |
| 219 | } |
| 220 | |
| 221 | vma = find_vma(mm, address); |
| 222 | if (!vma) |
| 223 | goto bad_area; |
| 224 | if (vma->vm_start <= address) |
| 225 | goto good_area; |
| 226 | if (!(vma->vm_flags & VM_GROWSDOWN)) |
| 227 | goto bad_area; |
| 228 | |
| 229 | /* |
| 230 | * N.B. The POWER/Open ABI allows programs to access up to |
| 231 | * 288 bytes below the stack pointer. |
| 232 | * The kernel signal delivery code writes up to about 1.5kB |
| 233 | * below the stack pointer (r1) before decrementing it. |
| 234 | * The exec code can write slightly over 640kB to the stack |
| 235 | * before setting the user r1. Thus we allow the stack to |
| 236 | * expand to 1MB without further checks. |
| 237 | */ |
| 238 | if (address + 0x100000 < vma->vm_end) { |
| 239 | /* get user regs even if this fault is in kernel mode */ |
| 240 | struct pt_regs *uregs = current->thread.regs; |
| 241 | if (uregs == NULL) |
| 242 | goto bad_area; |
| 243 | |
| 244 | /* |
| 245 | * A user-mode access to an address a long way below |
| 246 | * the stack pointer is only valid if the instruction |
| 247 | * is one which would update the stack pointer to the |
| 248 | * address accessed if the instruction completed, |
| 249 | * i.e. either stwu rs,n(r1) or stwux rs,r1,rb |
| 250 | * (or the byte, halfword, float or double forms). |
| 251 | * |
| 252 | * If we don't check this then any write to the area |
| 253 | * between the last mapped region and the stack will |
| 254 | * expand the stack rather than segfaulting. |
| 255 | */ |
| 256 | if (address + 2048 < uregs->gpr[1] |
| 257 | && (!user_mode(regs) || !store_updates_sp(regs))) |
| 258 | goto bad_area; |
| 259 | } |
| 260 | if (expand_stack(vma, address)) |
| 261 | goto bad_area; |
| 262 | |
| 263 | good_area: |
| 264 | code = SEGV_ACCERR; |
| 265 | #if defined(CONFIG_6xx) |
| 266 | if (error_code & 0x95700000) |
| 267 | /* an error such as lwarx to I/O controller space, |
| 268 | address matching DABR, eciwx, etc. */ |
| 269 | goto bad_area; |
| 270 | #endif /* CONFIG_6xx */ |
| 271 | #if defined(CONFIG_8xx) |
| 272 | /* The MPC8xx seems to always set 0x80000000, which is |
| 273 | * "undefined". Of those that can be set, this is the only |
| 274 | * one which seems bad. |
| 275 | */ |
| 276 | if (error_code & 0x10000000) |
| 277 | /* Guarded storage error. */ |
| 278 | goto bad_area; |
| 279 | #endif /* CONFIG_8xx */ |
| 280 | |
| 281 | if (is_exec) { |
Segher Boessenkool | 9ba4ace | 2007-06-20 01:07:04 +1000 | [diff] [blame] | 282 | #if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE)) |
Paul Mackerras | 14cf11a | 2005-09-26 16:04:21 +1000 | [diff] [blame] | 283 | /* protection fault */ |
| 284 | if (error_code & DSISR_PROTFAULT) |
| 285 | goto bad_area; |
Paul Mackerras | 08ae6cc | 2007-07-19 10:00:20 +1000 | [diff] [blame] | 286 | /* |
| 287 | * Allow execution from readable areas if the MMU does not |
| 288 | * provide separate controls over reading and executing. |
| 289 | */ |
| 290 | if (!(vma->vm_flags & VM_EXEC) && |
| 291 | (cpu_has_feature(CPU_FTR_NOEXECUTE) || |
| 292 | !(vma->vm_flags & (VM_READ | VM_WRITE)))) |
Paul Mackerras | 14cf11a | 2005-09-26 16:04:21 +1000 | [diff] [blame] | 293 | goto bad_area; |
Segher Boessenkool | 9ba4ace | 2007-06-20 01:07:04 +1000 | [diff] [blame] | 294 | #else |
Paul Mackerras | 14cf11a | 2005-09-26 16:04:21 +1000 | [diff] [blame] | 295 | pte_t *ptep; |
Eugene Surovegin | bab70a4 | 2006-03-28 10:13:12 -0800 | [diff] [blame] | 296 | pmd_t *pmdp; |
Paul Mackerras | 14cf11a | 2005-09-26 16:04:21 +1000 | [diff] [blame] | 297 | |
| 298 | /* Since 4xx/Book-E supports per-page execute permission, |
| 299 | * we lazily flush dcache to icache. */ |
| 300 | ptep = NULL; |
Eugene Surovegin | bab70a4 | 2006-03-28 10:13:12 -0800 | [diff] [blame] | 301 | if (get_pteptr(mm, address, &ptep, &pmdp)) { |
| 302 | spinlock_t *ptl = pte_lockptr(mm, pmdp); |
| 303 | spin_lock(ptl); |
| 304 | if (pte_present(*ptep)) { |
| 305 | struct page *page = pte_page(*ptep); |
Paul Mackerras | 14cf11a | 2005-09-26 16:04:21 +1000 | [diff] [blame] | 306 | |
Eugene Surovegin | bab70a4 | 2006-03-28 10:13:12 -0800 | [diff] [blame] | 307 | if (!test_bit(PG_arch_1, &page->flags)) { |
| 308 | flush_dcache_icache_page(page); |
| 309 | set_bit(PG_arch_1, &page->flags); |
| 310 | } |
| 311 | pte_update(ptep, 0, _PAGE_HWEXEC); |
Benjamin Herrenschmidt | e701d26 | 2007-10-30 09:46:06 +1100 | [diff] [blame] | 312 | _tlbie(address, mm->context.id); |
Eugene Surovegin | bab70a4 | 2006-03-28 10:13:12 -0800 | [diff] [blame] | 313 | pte_unmap_unlock(ptep, ptl); |
| 314 | up_read(&mm->mmap_sem); |
| 315 | return 0; |
Paul Mackerras | 14cf11a | 2005-09-26 16:04:21 +1000 | [diff] [blame] | 316 | } |
Eugene Surovegin | bab70a4 | 2006-03-28 10:13:12 -0800 | [diff] [blame] | 317 | pte_unmap_unlock(ptep, ptl); |
Paul Mackerras | 14cf11a | 2005-09-26 16:04:21 +1000 | [diff] [blame] | 318 | } |
Paul Mackerras | 14cf11a | 2005-09-26 16:04:21 +1000 | [diff] [blame] | 319 | #endif |
| 320 | /* a write */ |
| 321 | } else if (is_write) { |
| 322 | if (!(vma->vm_flags & VM_WRITE)) |
| 323 | goto bad_area; |
| 324 | /* a read */ |
| 325 | } else { |
| 326 | /* protection fault */ |
| 327 | if (error_code & 0x08000000) |
| 328 | goto bad_area; |
Jason Baron | df67b3d | 2006-09-29 01:58:58 -0700 | [diff] [blame] | 329 | if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))) |
Paul Mackerras | 14cf11a | 2005-09-26 16:04:21 +1000 | [diff] [blame] | 330 | goto bad_area; |
| 331 | } |
| 332 | |
| 333 | /* |
| 334 | * If for any reason at all we couldn't handle the fault, |
| 335 | * make sure we exit gracefully rather than endlessly redo |
| 336 | * the fault. |
| 337 | */ |
| 338 | survive: |
Nick Piggin | 83c5407 | 2007-07-19 01:47:05 -0700 | [diff] [blame] | 339 | ret = handle_mm_fault(mm, vma, address, is_write); |
| 340 | if (unlikely(ret & VM_FAULT_ERROR)) { |
| 341 | if (ret & VM_FAULT_OOM) |
| 342 | goto out_of_memory; |
| 343 | else if (ret & VM_FAULT_SIGBUS) |
| 344 | goto do_sigbus; |
Paul Mackerras | 14cf11a | 2005-09-26 16:04:21 +1000 | [diff] [blame] | 345 | BUG(); |
| 346 | } |
Nick Piggin | 83c5407 | 2007-07-19 01:47:05 -0700 | [diff] [blame] | 347 | if (ret & VM_FAULT_MAJOR) |
| 348 | current->maj_flt++; |
| 349 | else |
| 350 | current->min_flt++; |
Paul Mackerras | 14cf11a | 2005-09-26 16:04:21 +1000 | [diff] [blame] | 351 | up_read(&mm->mmap_sem); |
| 352 | return 0; |
| 353 | |
| 354 | bad_area: |
| 355 | up_read(&mm->mmap_sem); |
| 356 | |
| 357 | bad_area_nosemaphore: |
| 358 | /* User mode accesses cause a SIGSEGV */ |
| 359 | if (user_mode(regs)) { |
| 360 | _exception(SIGSEGV, regs, code, address); |
| 361 | return 0; |
| 362 | } |
| 363 | |
| 364 | if (is_exec && (error_code & DSISR_PROTFAULT) |
| 365 | && printk_ratelimit()) |
| 366 | printk(KERN_CRIT "kernel tried to execute NX-protected" |
| 367 | " page (%lx) - exploit attempt? (uid: %d)\n", |
| 368 | address, current->uid); |
| 369 | |
| 370 | return SIGSEGV; |
| 371 | |
| 372 | /* |
| 373 | * We ran out of memory, or some other thing happened to us that made |
| 374 | * us unable to handle the page fault gracefully. |
| 375 | */ |
| 376 | out_of_memory: |
| 377 | up_read(&mm->mmap_sem); |
Serge E. Hallyn | b460cbc | 2007-10-18 23:39:52 -0700 | [diff] [blame] | 378 | if (is_global_init(current)) { |
Paul Mackerras | 14cf11a | 2005-09-26 16:04:21 +1000 | [diff] [blame] | 379 | yield(); |
| 380 | down_read(&mm->mmap_sem); |
| 381 | goto survive; |
| 382 | } |
| 383 | printk("VM: killing process %s\n", current->comm); |
| 384 | if (user_mode(regs)) |
will schmidt | effe24bd | 2007-06-13 01:19:01 +1000 | [diff] [blame] | 385 | do_group_exit(SIGKILL); |
Paul Mackerras | 14cf11a | 2005-09-26 16:04:21 +1000 | [diff] [blame] | 386 | return SIGKILL; |
| 387 | |
| 388 | do_sigbus: |
| 389 | up_read(&mm->mmap_sem); |
| 390 | if (user_mode(regs)) { |
| 391 | info.si_signo = SIGBUS; |
| 392 | info.si_errno = 0; |
| 393 | info.si_code = BUS_ADRERR; |
| 394 | info.si_addr = (void __user *)address; |
| 395 | force_sig_info(SIGBUS, &info, current); |
| 396 | return 0; |
| 397 | } |
| 398 | return SIGBUS; |
| 399 | } |
| 400 | |
| 401 | /* |
| 402 | * bad_page_fault is called when we have a bad access from the kernel. |
| 403 | * It is called from the DSI and ISI handlers in head.S and from some |
| 404 | * of the procedures in traps.c. |
| 405 | */ |
| 406 | void bad_page_fault(struct pt_regs *regs, unsigned long address, int sig) |
| 407 | { |
| 408 | const struct exception_table_entry *entry; |
| 409 | |
| 410 | /* Are we prepared to handle this fault? */ |
| 411 | if ((entry = search_exception_tables(regs->nip)) != NULL) { |
| 412 | regs->nip = entry->fixup; |
| 413 | return; |
| 414 | } |
| 415 | |
| 416 | /* kernel has accessed a bad area */ |
Olof Johansson | 723925b | 2005-11-06 14:54:36 -0800 | [diff] [blame] | 417 | |
Olof Johansson | 723925b | 2005-11-06 14:54:36 -0800 | [diff] [blame] | 418 | switch (regs->trap) { |
Michael Ellerman | a416dd8 | 2006-11-08 10:22:59 +1100 | [diff] [blame] | 419 | case 0x300: |
| 420 | case 0x380: |
| 421 | printk(KERN_ALERT "Unable to handle kernel paging request for " |
| 422 | "data at address 0x%08lx\n", regs->dar); |
| 423 | break; |
| 424 | case 0x400: |
| 425 | case 0x480: |
| 426 | printk(KERN_ALERT "Unable to handle kernel paging request for " |
| 427 | "instruction fetch\n"); |
| 428 | break; |
| 429 | default: |
| 430 | printk(KERN_ALERT "Unable to handle kernel paging request for " |
| 431 | "unknown fault\n"); |
| 432 | break; |
Olof Johansson | 723925b | 2005-11-06 14:54:36 -0800 | [diff] [blame] | 433 | } |
| 434 | printk(KERN_ALERT "Faulting instruction address: 0x%08lx\n", |
| 435 | regs->nip); |
| 436 | |
Paul Mackerras | 14cf11a | 2005-09-26 16:04:21 +1000 | [diff] [blame] | 437 | die("Kernel access of bad area", regs, sig); |
| 438 | } |