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1d18c47c CM |
1 | /* |
2 | * Based on arch/arm/mm/fault.c | |
3 | * | |
4 | * Copyright (C) 1995 Linus Torvalds | |
5 | * Copyright (C) 1995-2004 Russell King | |
6 | * Copyright (C) 2012 ARM Ltd. | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | * | |
12 | * This program is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | * GNU General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU General Public License | |
18 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
19 | */ | |
20 | ||
0edfa839 | 21 | #include <linux/extable.h> |
1d18c47c CM |
22 | #include <linux/signal.h> |
23 | #include <linux/mm.h> | |
24 | #include <linux/hardirq.h> | |
25 | #include <linux/init.h> | |
26 | #include <linux/kprobes.h> | |
27 | #include <linux/uaccess.h> | |
28 | #include <linux/page-flags.h> | |
3f07c014 | 29 | #include <linux/sched/signal.h> |
b17b0153 | 30 | #include <linux/sched/debug.h> |
1d18c47c CM |
31 | #include <linux/highmem.h> |
32 | #include <linux/perf_event.h> | |
7209c868 | 33 | #include <linux/preempt.h> |
e7c600f1 | 34 | #include <linux/hugetlb.h> |
1d18c47c | 35 | |
7209c868 | 36 | #include <asm/bug.h> |
338d4f49 | 37 | #include <asm/cpufeature.h> |
1d18c47c CM |
38 | #include <asm/exception.h> |
39 | #include <asm/debug-monitors.h> | |
9141300a | 40 | #include <asm/esr.h> |
338d4f49 | 41 | #include <asm/sysreg.h> |
1d18c47c CM |
42 | #include <asm/system_misc.h> |
43 | #include <asm/pgtable.h> | |
44 | #include <asm/tlbflush.h> | |
45 | ||
7edda088 TB |
46 | #include <acpi/ghes.h> |
47 | ||
09a6adf5 VK |
48 | struct fault_info { |
49 | int (*fn)(unsigned long addr, unsigned int esr, | |
50 | struct pt_regs *regs); | |
51 | int sig; | |
52 | int code; | |
53 | const char *name; | |
54 | }; | |
55 | ||
56 | static const struct fault_info fault_info[]; | |
57 | ||
58 | static inline const struct fault_info *esr_to_fault_info(unsigned int esr) | |
59 | { | |
60 | return fault_info + (esr & 63); | |
61 | } | |
3495386b | 62 | |
2dd0e8d2 SP |
63 | #ifdef CONFIG_KPROBES |
64 | static inline int notify_page_fault(struct pt_regs *regs, unsigned int esr) | |
65 | { | |
66 | int ret = 0; | |
67 | ||
68 | /* kprobe_running() needs smp_processor_id() */ | |
69 | if (!user_mode(regs)) { | |
70 | preempt_disable(); | |
71 | if (kprobe_running() && kprobe_fault_handler(regs, esr)) | |
72 | ret = 1; | |
73 | preempt_enable(); | |
74 | } | |
75 | ||
76 | return ret; | |
77 | } | |
78 | #else | |
79 | static inline int notify_page_fault(struct pt_regs *regs, unsigned int esr) | |
80 | { | |
81 | return 0; | |
82 | } | |
83 | #endif | |
84 | ||
1d18c47c | 85 | /* |
67ce16ec | 86 | * Dump out the page tables associated with 'addr' in the currently active mm. |
1d18c47c | 87 | */ |
67ce16ec | 88 | void show_pte(unsigned long addr) |
1d18c47c | 89 | { |
67ce16ec | 90 | struct mm_struct *mm; |
1d18c47c CM |
91 | pgd_t *pgd; |
92 | ||
67ce16ec KM |
93 | if (addr < TASK_SIZE) { |
94 | /* TTBR0 */ | |
95 | mm = current->active_mm; | |
96 | if (mm == &init_mm) { | |
97 | pr_alert("[%016lx] user address but active_mm is swapper\n", | |
98 | addr); | |
99 | return; | |
100 | } | |
101 | } else if (addr >= VA_START) { | |
102 | /* TTBR1 */ | |
1d18c47c | 103 | mm = &init_mm; |
67ce16ec KM |
104 | } else { |
105 | pr_alert("[%016lx] address between user and kernel address ranges\n", | |
106 | addr); | |
107 | return; | |
108 | } | |
1d18c47c | 109 | |
1eb34b6e WD |
110 | pr_alert("%s pgtable: %luk pages, %u-bit VAs, pgd = %p\n", |
111 | mm == &init_mm ? "swapper" : "user", PAGE_SIZE / SZ_1K, | |
112 | VA_BITS, mm->pgd); | |
1d18c47c | 113 | pgd = pgd_offset(mm, addr); |
67ce16ec | 114 | pr_alert("[%016lx] *pgd=%016llx", addr, pgd_val(*pgd)); |
1d18c47c CM |
115 | |
116 | do { | |
117 | pud_t *pud; | |
118 | pmd_t *pmd; | |
119 | pte_t *pte; | |
120 | ||
4339e3f3 | 121 | if (pgd_none(*pgd) || pgd_bad(*pgd)) |
1d18c47c CM |
122 | break; |
123 | ||
124 | pud = pud_offset(pgd, addr); | |
6ef4fb38 | 125 | pr_cont(", *pud=%016llx", pud_val(*pud)); |
4339e3f3 | 126 | if (pud_none(*pud) || pud_bad(*pud)) |
1d18c47c CM |
127 | break; |
128 | ||
129 | pmd = pmd_offset(pud, addr); | |
6ef4fb38 | 130 | pr_cont(", *pmd=%016llx", pmd_val(*pmd)); |
4339e3f3 | 131 | if (pmd_none(*pmd) || pmd_bad(*pmd)) |
1d18c47c CM |
132 | break; |
133 | ||
134 | pte = pte_offset_map(pmd, addr); | |
6ef4fb38 | 135 | pr_cont(", *pte=%016llx", pte_val(*pte)); |
1d18c47c CM |
136 | pte_unmap(pte); |
137 | } while(0); | |
138 | ||
6ef4fb38 | 139 | pr_cont("\n"); |
1d18c47c CM |
140 | } |
141 | ||
66dbd6e6 CM |
142 | #ifdef CONFIG_ARM64_HW_AFDBM |
143 | /* | |
144 | * This function sets the access flags (dirty, accessed), as well as write | |
145 | * permission, and only to a more permissive setting. | |
146 | * | |
147 | * It needs to cope with hardware update of the accessed/dirty state by other | |
148 | * agents in the system and can safely skip the __sync_icache_dcache() call as, | |
149 | * like set_pte_at(), the PTE is never changed from no-exec to exec here. | |
150 | * | |
151 | * Returns whether or not the PTE actually changed. | |
152 | */ | |
153 | int ptep_set_access_flags(struct vm_area_struct *vma, | |
154 | unsigned long address, pte_t *ptep, | |
155 | pte_t entry, int dirty) | |
156 | { | |
157 | pteval_t old_pteval; | |
158 | unsigned int tmp; | |
159 | ||
160 | if (pte_same(*ptep, entry)) | |
161 | return 0; | |
162 | ||
163 | /* only preserve the access flags and write permission */ | |
164 | pte_val(entry) &= PTE_AF | PTE_WRITE | PTE_DIRTY; | |
165 | ||
6d332747 | 166 | /* set PTE_RDONLY if actual read-only or clean PTE */ |
0106d456 | 167 | if (!pte_write(entry) || !pte_sw_dirty(entry)) |
66dbd6e6 CM |
168 | pte_val(entry) |= PTE_RDONLY; |
169 | ||
170 | /* | |
171 | * Setting the flags must be done atomically to avoid racing with the | |
6d332747 CM |
172 | * hardware update of the access/dirty state. The PTE_RDONLY bit must |
173 | * be set to the most permissive (lowest value) of *ptep and entry | |
174 | * (calculated as: a & b == ~(~a | ~b)). | |
66dbd6e6 | 175 | */ |
6d332747 | 176 | pte_val(entry) ^= PTE_RDONLY; |
66dbd6e6 CM |
177 | asm volatile("// ptep_set_access_flags\n" |
178 | " prfm pstl1strm, %2\n" | |
179 | "1: ldxr %0, %2\n" | |
6d332747 | 180 | " eor %0, %0, %3 // negate PTE_RDONLY in *ptep\n" |
66dbd6e6 | 181 | " orr %0, %0, %4 // set flags\n" |
6d332747 | 182 | " eor %0, %0, %3 // negate final PTE_RDONLY\n" |
66dbd6e6 CM |
183 | " stxr %w1, %0, %2\n" |
184 | " cbnz %w1, 1b\n" | |
185 | : "=&r" (old_pteval), "=&r" (tmp), "+Q" (pte_val(*ptep)) | |
6d332747 | 186 | : "L" (PTE_RDONLY), "r" (pte_val(entry))); |
66dbd6e6 CM |
187 | |
188 | flush_tlb_fix_spurious_fault(vma, address); | |
189 | return 1; | |
190 | } | |
191 | #endif | |
192 | ||
9adeb8e7 LA |
193 | static bool is_el1_instruction_abort(unsigned int esr) |
194 | { | |
195 | return ESR_ELx_EC(esr) == ESR_ELx_EC_IABT_CUR; | |
196 | } | |
197 | ||
b824b930 SB |
198 | static inline bool is_permission_fault(unsigned int esr, struct pt_regs *regs, |
199 | unsigned long addr) | |
200 | { | |
201 | unsigned int ec = ESR_ELx_EC(esr); | |
202 | unsigned int fsc_type = esr & ESR_ELx_FSC_TYPE; | |
203 | ||
204 | if (ec != ESR_ELx_EC_DABT_CUR && ec != ESR_ELx_EC_IABT_CUR) | |
205 | return false; | |
206 | ||
207 | if (fsc_type == ESR_ELx_FSC_PERM) | |
208 | return true; | |
209 | ||
210 | if (addr < USER_DS && system_uses_ttbr0_pan()) | |
211 | return fsc_type == ESR_ELx_FSC_FAULT && | |
212 | (regs->pstate & PSR_PAN_BIT); | |
213 | ||
214 | return false; | |
215 | } | |
216 | ||
1d18c47c CM |
217 | /* |
218 | * The kernel tried to access some page that wasn't present. | |
219 | */ | |
67ce16ec KM |
220 | static void __do_kernel_fault(unsigned long addr, unsigned int esr, |
221 | struct pt_regs *regs) | |
1d18c47c | 222 | { |
b824b930 SB |
223 | const char *msg; |
224 | ||
1d18c47c CM |
225 | /* |
226 | * Are we prepared to handle this kernel fault? | |
9adeb8e7 | 227 | * We are almost certainly not prepared to handle instruction faults. |
1d18c47c | 228 | */ |
9adeb8e7 | 229 | if (!is_el1_instruction_abort(esr) && fixup_exception(regs)) |
1d18c47c CM |
230 | return; |
231 | ||
232 | /* | |
233 | * No handler, we'll have to terminate things with extreme prejudice. | |
234 | */ | |
235 | bust_spinlocks(1); | |
b824b930 SB |
236 | |
237 | if (is_permission_fault(esr, regs, addr)) { | |
238 | if (esr & ESR_ELx_WNR) | |
239 | msg = "write to read-only memory"; | |
240 | else | |
241 | msg = "read from unreadable memory"; | |
242 | } else if (addr < PAGE_SIZE) { | |
243 | msg = "NULL pointer dereference"; | |
244 | } else { | |
245 | msg = "paging request"; | |
246 | } | |
247 | ||
248 | pr_alert("Unable to handle kernel %s at virtual address %08lx\n", msg, | |
249 | addr); | |
1d18c47c | 250 | |
67ce16ec | 251 | show_pte(addr); |
1d18c47c CM |
252 | die("Oops", regs, esr); |
253 | bust_spinlocks(0); | |
254 | do_exit(SIGKILL); | |
255 | } | |
256 | ||
257 | /* | |
258 | * Something tried to access memory that isn't in our memory map. User mode | |
259 | * accesses just cause a SIGSEGV | |
260 | */ | |
261 | static void __do_user_fault(struct task_struct *tsk, unsigned long addr, | |
262 | unsigned int esr, unsigned int sig, int code, | |
e7c600f1 | 263 | struct pt_regs *regs, int fault) |
1d18c47c CM |
264 | { |
265 | struct siginfo si; | |
09a6adf5 | 266 | const struct fault_info *inf; |
e7c600f1 | 267 | unsigned int lsb = 0; |
1d18c47c | 268 | |
f871d268 | 269 | if (unhandled_signal(tsk, sig) && show_unhandled_signals_ratelimited()) { |
09a6adf5 | 270 | inf = esr_to_fault_info(esr); |
83016b20 | 271 | pr_info("%s[%d]: unhandled %s (%d) at 0x%08lx, esr 0x%03x", |
09a6adf5 | 272 | tsk->comm, task_pid_nr(tsk), inf->name, sig, |
3495386b | 273 | addr, esr); |
83016b20 KM |
274 | print_vma_addr(KERN_CONT ", in ", regs->pc); |
275 | pr_cont("\n"); | |
c07ab957 | 276 | __show_regs(regs); |
1d18c47c CM |
277 | } |
278 | ||
279 | tsk->thread.fault_address = addr; | |
9141300a | 280 | tsk->thread.fault_code = esr; |
1d18c47c CM |
281 | si.si_signo = sig; |
282 | si.si_errno = 0; | |
283 | si.si_code = code; | |
284 | si.si_addr = (void __user *)addr; | |
e7c600f1 JZZ |
285 | /* |
286 | * Either small page or large page may be poisoned. | |
287 | * In other words, VM_FAULT_HWPOISON_LARGE and | |
288 | * VM_FAULT_HWPOISON are mutually exclusive. | |
289 | */ | |
290 | if (fault & VM_FAULT_HWPOISON_LARGE) | |
291 | lsb = hstate_index_to_shift(VM_FAULT_GET_HINDEX(fault)); | |
292 | else if (fault & VM_FAULT_HWPOISON) | |
293 | lsb = PAGE_SHIFT; | |
294 | si.si_addr_lsb = lsb; | |
295 | ||
1d18c47c CM |
296 | force_sig_info(sig, &si, tsk); |
297 | } | |
298 | ||
59f67e16 | 299 | static void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *regs) |
1d18c47c CM |
300 | { |
301 | struct task_struct *tsk = current; | |
09a6adf5 | 302 | const struct fault_info *inf; |
1d18c47c CM |
303 | |
304 | /* | |
305 | * If we are in kernel mode at this point, we have no context to | |
306 | * handle this fault with. | |
307 | */ | |
09a6adf5 VK |
308 | if (user_mode(regs)) { |
309 | inf = esr_to_fault_info(esr); | |
e7c600f1 | 310 | __do_user_fault(tsk, addr, esr, inf->sig, inf->code, regs, 0); |
09a6adf5 | 311 | } else |
67ce16ec | 312 | __do_kernel_fault(addr, esr, regs); |
1d18c47c CM |
313 | } |
314 | ||
315 | #define VM_FAULT_BADMAP 0x010000 | |
316 | #define VM_FAULT_BADACCESS 0x020000 | |
317 | ||
1d18c47c | 318 | static int __do_page_fault(struct mm_struct *mm, unsigned long addr, |
db6f4106 | 319 | unsigned int mm_flags, unsigned long vm_flags, |
1d18c47c CM |
320 | struct task_struct *tsk) |
321 | { | |
322 | struct vm_area_struct *vma; | |
323 | int fault; | |
324 | ||
325 | vma = find_vma(mm, addr); | |
326 | fault = VM_FAULT_BADMAP; | |
327 | if (unlikely(!vma)) | |
328 | goto out; | |
329 | if (unlikely(vma->vm_start > addr)) | |
330 | goto check_stack; | |
331 | ||
332 | /* | |
333 | * Ok, we have a good vm_area for this memory access, so we can handle | |
334 | * it. | |
335 | */ | |
336 | good_area: | |
db6f4106 WD |
337 | /* |
338 | * Check that the permissions on the VMA allow for the fault which | |
cab15ce6 | 339 | * occurred. |
db6f4106 WD |
340 | */ |
341 | if (!(vma->vm_flags & vm_flags)) { | |
1d18c47c CM |
342 | fault = VM_FAULT_BADACCESS; |
343 | goto out; | |
344 | } | |
345 | ||
dcddffd4 | 346 | return handle_mm_fault(vma, addr & PAGE_MASK, mm_flags); |
1d18c47c CM |
347 | |
348 | check_stack: | |
349 | if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr)) | |
350 | goto good_area; | |
351 | out: | |
352 | return fault; | |
353 | } | |
354 | ||
541ec870 MR |
355 | static bool is_el0_instruction_abort(unsigned int esr) |
356 | { | |
357 | return ESR_ELx_EC(esr) == ESR_ELx_EC_IABT_LOW; | |
358 | } | |
359 | ||
1d18c47c CM |
360 | static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, |
361 | struct pt_regs *regs) | |
362 | { | |
363 | struct task_struct *tsk; | |
364 | struct mm_struct *mm; | |
0e3a9026 | 365 | int fault, sig, code, major = 0; |
cab15ce6 | 366 | unsigned long vm_flags = VM_READ | VM_WRITE; |
db6f4106 WD |
367 | unsigned int mm_flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; |
368 | ||
2dd0e8d2 SP |
369 | if (notify_page_fault(regs, esr)) |
370 | return 0; | |
371 | ||
1d18c47c CM |
372 | tsk = current; |
373 | mm = tsk->mm; | |
374 | ||
1d18c47c CM |
375 | /* |
376 | * If we're in an interrupt or have no user context, we must not take | |
377 | * the fault. | |
378 | */ | |
70ffdb93 | 379 | if (faulthandler_disabled() || !mm) |
1d18c47c CM |
380 | goto no_context; |
381 | ||
759496ba JW |
382 | if (user_mode(regs)) |
383 | mm_flags |= FAULT_FLAG_USER; | |
384 | ||
541ec870 | 385 | if (is_el0_instruction_abort(esr)) { |
759496ba | 386 | vm_flags = VM_EXEC; |
aed40e01 | 387 | } else if ((esr & ESR_ELx_WNR) && !(esr & ESR_ELx_CM)) { |
759496ba JW |
388 | vm_flags = VM_WRITE; |
389 | mm_flags |= FAULT_FLAG_WRITE; | |
390 | } | |
391 | ||
b824b930 | 392 | if (addr < USER_DS && is_permission_fault(esr, regs, addr)) { |
e19a6ee2 JM |
393 | /* regs->orig_addr_limit may be 0 if we entered from EL0 */ |
394 | if (regs->orig_addr_limit == KERNEL_DS) | |
70c8abc2 | 395 | die("Accessing user space memory with fs=KERNEL_DS", regs, esr); |
70544196 | 396 | |
9adeb8e7 LA |
397 | if (is_el1_instruction_abort(esr)) |
398 | die("Attempting to execute userspace memory", regs, esr); | |
399 | ||
57f4959b | 400 | if (!search_exception_tables(regs->pc)) |
70c8abc2 | 401 | die("Accessing user space memory outside uaccess.h routines", regs, esr); |
57f4959b | 402 | } |
338d4f49 | 403 | |
0e3a9026 PA |
404 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr); |
405 | ||
1d18c47c CM |
406 | /* |
407 | * As per x86, we may deadlock here. However, since the kernel only | |
408 | * validly references user space from well defined areas of the code, | |
409 | * we can bug out early if this is from code which shouldn't. | |
410 | */ | |
411 | if (!down_read_trylock(&mm->mmap_sem)) { | |
412 | if (!user_mode(regs) && !search_exception_tables(regs->pc)) | |
413 | goto no_context; | |
414 | retry: | |
415 | down_read(&mm->mmap_sem); | |
416 | } else { | |
417 | /* | |
418 | * The above down_read_trylock() might have succeeded in which | |
419 | * case, we'll have missed the might_sleep() from down_read(). | |
420 | */ | |
421 | might_sleep(); | |
422 | #ifdef CONFIG_DEBUG_VM | |
423 | if (!user_mode(regs) && !search_exception_tables(regs->pc)) | |
424 | goto no_context; | |
425 | #endif | |
426 | } | |
427 | ||
db6f4106 | 428 | fault = __do_page_fault(mm, addr, mm_flags, vm_flags, tsk); |
0e3a9026 | 429 | major |= fault & VM_FAULT_MAJOR; |
1d18c47c | 430 | |
0e3a9026 PA |
431 | if (fault & VM_FAULT_RETRY) { |
432 | /* | |
433 | * If we need to retry but a fatal signal is pending, | |
434 | * handle the signal first. We do not need to release | |
435 | * the mmap_sem because it would already be released | |
436 | * in __lock_page_or_retry in mm/filemap.c. | |
437 | */ | |
289d07a2 MR |
438 | if (fatal_signal_pending(current)) { |
439 | if (!user_mode(regs)) | |
440 | goto no_context; | |
0e3a9026 | 441 | return 0; |
289d07a2 | 442 | } |
0e3a9026 PA |
443 | |
444 | /* | |
445 | * Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk of | |
446 | * starvation. | |
447 | */ | |
448 | if (mm_flags & FAULT_FLAG_ALLOW_RETRY) { | |
449 | mm_flags &= ~FAULT_FLAG_ALLOW_RETRY; | |
450 | mm_flags |= FAULT_FLAG_TRIED; | |
451 | goto retry; | |
452 | } | |
453 | } | |
454 | up_read(&mm->mmap_sem); | |
1d18c47c CM |
455 | |
456 | /* | |
0e3a9026 | 457 | * Handle the "normal" (no error) case first. |
1d18c47c | 458 | */ |
0e3a9026 PA |
459 | if (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP | |
460 | VM_FAULT_BADACCESS)))) { | |
461 | /* | |
462 | * Major/minor page fault accounting is only done | |
463 | * once. If we go through a retry, it is extremely | |
464 | * likely that the page will be found in page cache at | |
465 | * that point. | |
466 | */ | |
467 | if (major) { | |
1d18c47c CM |
468 | tsk->maj_flt++; |
469 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, | |
470 | addr); | |
471 | } else { | |
472 | tsk->min_flt++; | |
473 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, | |
474 | addr); | |
475 | } | |
1d18c47c | 476 | |
1d18c47c | 477 | return 0; |
0e3a9026 | 478 | } |
1d18c47c | 479 | |
87134102 JW |
480 | /* |
481 | * If we are in kernel mode at this point, we have no context to | |
482 | * handle this fault with. | |
483 | */ | |
484 | if (!user_mode(regs)) | |
485 | goto no_context; | |
486 | ||
1d18c47c CM |
487 | if (fault & VM_FAULT_OOM) { |
488 | /* | |
489 | * We ran out of memory, call the OOM killer, and return to | |
490 | * userspace (which will retry the fault, or kill us if we got | |
491 | * oom-killed). | |
492 | */ | |
493 | pagefault_out_of_memory(); | |
494 | return 0; | |
495 | } | |
496 | ||
1d18c47c CM |
497 | if (fault & VM_FAULT_SIGBUS) { |
498 | /* | |
499 | * We had some memory, but were unable to successfully fix up | |
500 | * this page fault. | |
501 | */ | |
502 | sig = SIGBUS; | |
503 | code = BUS_ADRERR; | |
e7c600f1 JZZ |
504 | } else if (fault & (VM_FAULT_HWPOISON | VM_FAULT_HWPOISON_LARGE)) { |
505 | sig = SIGBUS; | |
506 | code = BUS_MCEERR_AR; | |
1d18c47c CM |
507 | } else { |
508 | /* | |
509 | * Something tried to access memory that isn't in our memory | |
510 | * map. | |
511 | */ | |
512 | sig = SIGSEGV; | |
513 | code = fault == VM_FAULT_BADACCESS ? | |
514 | SEGV_ACCERR : SEGV_MAPERR; | |
515 | } | |
516 | ||
e7c600f1 | 517 | __do_user_fault(tsk, addr, esr, sig, code, regs, fault); |
1d18c47c CM |
518 | return 0; |
519 | ||
520 | no_context: | |
67ce16ec | 521 | __do_kernel_fault(addr, esr, regs); |
1d18c47c CM |
522 | return 0; |
523 | } | |
524 | ||
525 | /* | |
526 | * First Level Translation Fault Handler | |
527 | * | |
528 | * We enter here because the first level page table doesn't contain a valid | |
529 | * entry for the address. | |
530 | * | |
531 | * If the address is in kernel space (>= TASK_SIZE), then we are probably | |
532 | * faulting in the vmalloc() area. | |
533 | * | |
534 | * If the init_task's first level page tables contains the relevant entry, we | |
535 | * copy the it to this task. If not, we send the process a signal, fixup the | |
536 | * exception, or oops the kernel. | |
537 | * | |
538 | * NOTE! We MUST NOT take any locks for this case. We may be in an interrupt | |
539 | * or a critical region, and should only copy the information from the master | |
540 | * page table, nothing more. | |
541 | */ | |
542 | static int __kprobes do_translation_fault(unsigned long addr, | |
543 | unsigned int esr, | |
544 | struct pt_regs *regs) | |
545 | { | |
546 | if (addr < TASK_SIZE) | |
547 | return do_page_fault(addr, esr, regs); | |
548 | ||
549 | do_bad_area(addr, esr, regs); | |
550 | return 0; | |
551 | } | |
552 | ||
52d7523d EL |
553 | static int do_alignment_fault(unsigned long addr, unsigned int esr, |
554 | struct pt_regs *regs) | |
555 | { | |
556 | do_bad_area(addr, esr, regs); | |
557 | return 0; | |
558 | } | |
559 | ||
1d18c47c CM |
560 | /* |
561 | * This abort handler always returns "fault". | |
562 | */ | |
563 | static int do_bad(unsigned long addr, unsigned int esr, struct pt_regs *regs) | |
564 | { | |
565 | return 1; | |
566 | } | |
567 | ||
32015c23 TB |
568 | /* |
569 | * This abort handler deals with Synchronous External Abort. | |
570 | * It calls notifiers, and then returns "fault". | |
571 | */ | |
572 | static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs) | |
573 | { | |
574 | struct siginfo info; | |
575 | const struct fault_info *inf; | |
621f48e4 | 576 | int ret = 0; |
32015c23 TB |
577 | |
578 | inf = esr_to_fault_info(esr); | |
579 | pr_err("Synchronous External Abort: %s (0x%08x) at 0x%016lx\n", | |
580 | inf->name, esr, addr); | |
581 | ||
7edda088 TB |
582 | /* |
583 | * Synchronous aborts may interrupt code which had interrupts masked. | |
584 | * Before calling out into the wider kernel tell the interested | |
585 | * subsystems. | |
586 | */ | |
587 | if (IS_ENABLED(CONFIG_ACPI_APEI_SEA)) { | |
588 | if (interrupts_enabled(regs)) | |
589 | nmi_enter(); | |
590 | ||
621f48e4 | 591 | ret = ghes_notify_sea(); |
7edda088 TB |
592 | |
593 | if (interrupts_enabled(regs)) | |
594 | nmi_exit(); | |
595 | } | |
596 | ||
32015c23 TB |
597 | info.si_signo = SIGBUS; |
598 | info.si_errno = 0; | |
599 | info.si_code = 0; | |
600 | if (esr & ESR_ELx_FnV) | |
601 | info.si_addr = NULL; | |
602 | else | |
603 | info.si_addr = (void __user *)addr; | |
604 | arm64_notify_die("", regs, &info, esr); | |
605 | ||
621f48e4 | 606 | return ret; |
32015c23 TB |
607 | } |
608 | ||
09a6adf5 | 609 | static const struct fault_info fault_info[] = { |
1d18c47c CM |
610 | { do_bad, SIGBUS, 0, "ttbr address size fault" }, |
611 | { do_bad, SIGBUS, 0, "level 1 address size fault" }, | |
612 | { do_bad, SIGBUS, 0, "level 2 address size fault" }, | |
613 | { do_bad, SIGBUS, 0, "level 3 address size fault" }, | |
7f73f7ae | 614 | { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 0 translation fault" }, |
1d18c47c CM |
615 | { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 1 translation fault" }, |
616 | { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 2 translation fault" }, | |
617 | { do_page_fault, SIGSEGV, SEGV_MAPERR, "level 3 translation fault" }, | |
c03784ee | 618 | { do_bad, SIGBUS, 0, "unknown 8" }, |
084bd298 SC |
619 | { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 1 access flag fault" }, |
620 | { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 2 access flag fault" }, | |
1d18c47c | 621 | { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 3 access flag fault" }, |
c03784ee | 622 | { do_bad, SIGBUS, 0, "unknown 12" }, |
084bd298 SC |
623 | { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 1 permission fault" }, |
624 | { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 2 permission fault" }, | |
1d18c47c | 625 | { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 3 permission fault" }, |
32015c23 | 626 | { do_sea, SIGBUS, 0, "synchronous external abort" }, |
c03784ee | 627 | { do_bad, SIGBUS, 0, "unknown 17" }, |
1d18c47c CM |
628 | { do_bad, SIGBUS, 0, "unknown 18" }, |
629 | { do_bad, SIGBUS, 0, "unknown 19" }, | |
32015c23 TB |
630 | { do_sea, SIGBUS, 0, "level 0 (translation table walk)" }, |
631 | { do_sea, SIGBUS, 0, "level 1 (translation table walk)" }, | |
632 | { do_sea, SIGBUS, 0, "level 2 (translation table walk)" }, | |
633 | { do_sea, SIGBUS, 0, "level 3 (translation table walk)" }, | |
634 | { do_sea, SIGBUS, 0, "synchronous parity or ECC error" }, | |
c03784ee | 635 | { do_bad, SIGBUS, 0, "unknown 25" }, |
1d18c47c CM |
636 | { do_bad, SIGBUS, 0, "unknown 26" }, |
637 | { do_bad, SIGBUS, 0, "unknown 27" }, | |
32015c23 TB |
638 | { do_sea, SIGBUS, 0, "level 0 synchronous parity error (translation table walk)" }, |
639 | { do_sea, SIGBUS, 0, "level 1 synchronous parity error (translation table walk)" }, | |
640 | { do_sea, SIGBUS, 0, "level 2 synchronous parity error (translation table walk)" }, | |
641 | { do_sea, SIGBUS, 0, "level 3 synchronous parity error (translation table walk)" }, | |
1d18c47c | 642 | { do_bad, SIGBUS, 0, "unknown 32" }, |
52d7523d | 643 | { do_alignment_fault, SIGBUS, BUS_ADRALN, "alignment fault" }, |
c03784ee | 644 | { do_bad, SIGBUS, 0, "unknown 34" }, |
1d18c47c CM |
645 | { do_bad, SIGBUS, 0, "unknown 35" }, |
646 | { do_bad, SIGBUS, 0, "unknown 36" }, | |
647 | { do_bad, SIGBUS, 0, "unknown 37" }, | |
648 | { do_bad, SIGBUS, 0, "unknown 38" }, | |
649 | { do_bad, SIGBUS, 0, "unknown 39" }, | |
650 | { do_bad, SIGBUS, 0, "unknown 40" }, | |
651 | { do_bad, SIGBUS, 0, "unknown 41" }, | |
652 | { do_bad, SIGBUS, 0, "unknown 42" }, | |
653 | { do_bad, SIGBUS, 0, "unknown 43" }, | |
654 | { do_bad, SIGBUS, 0, "unknown 44" }, | |
655 | { do_bad, SIGBUS, 0, "unknown 45" }, | |
656 | { do_bad, SIGBUS, 0, "unknown 46" }, | |
657 | { do_bad, SIGBUS, 0, "unknown 47" }, | |
c03784ee | 658 | { do_bad, SIGBUS, 0, "TLB conflict abort" }, |
1d18c47c CM |
659 | { do_bad, SIGBUS, 0, "unknown 49" }, |
660 | { do_bad, SIGBUS, 0, "unknown 50" }, | |
661 | { do_bad, SIGBUS, 0, "unknown 51" }, | |
662 | { do_bad, SIGBUS, 0, "implementation fault (lockdown abort)" }, | |
c03784ee | 663 | { do_bad, SIGBUS, 0, "implementation fault (unsupported exclusive)" }, |
1d18c47c CM |
664 | { do_bad, SIGBUS, 0, "unknown 54" }, |
665 | { do_bad, SIGBUS, 0, "unknown 55" }, | |
666 | { do_bad, SIGBUS, 0, "unknown 56" }, | |
667 | { do_bad, SIGBUS, 0, "unknown 57" }, | |
c03784ee | 668 | { do_bad, SIGBUS, 0, "unknown 58" }, |
1d18c47c CM |
669 | { do_bad, SIGBUS, 0, "unknown 59" }, |
670 | { do_bad, SIGBUS, 0, "unknown 60" }, | |
c03784ee MR |
671 | { do_bad, SIGBUS, 0, "section domain fault" }, |
672 | { do_bad, SIGBUS, 0, "page domain fault" }, | |
1d18c47c CM |
673 | { do_bad, SIGBUS, 0, "unknown 63" }, |
674 | }; | |
675 | ||
621f48e4 TB |
676 | /* |
677 | * Handle Synchronous External Aborts that occur in a guest kernel. | |
678 | * | |
679 | * The return value will be zero if the SEA was successfully handled | |
680 | * and non-zero if there was an error processing the error or there was | |
681 | * no error to process. | |
682 | */ | |
683 | int handle_guest_sea(phys_addr_t addr, unsigned int esr) | |
684 | { | |
685 | int ret = -ENOENT; | |
686 | ||
687 | if (IS_ENABLED(CONFIG_ACPI_APEI_SEA)) | |
688 | ret = ghes_notify_sea(); | |
689 | ||
690 | return ret; | |
691 | } | |
692 | ||
1d18c47c CM |
693 | /* |
694 | * Dispatch a data abort to the relevant handler. | |
695 | */ | |
696 | asmlinkage void __exception do_mem_abort(unsigned long addr, unsigned int esr, | |
697 | struct pt_regs *regs) | |
698 | { | |
09a6adf5 | 699 | const struct fault_info *inf = esr_to_fault_info(esr); |
1d18c47c CM |
700 | struct siginfo info; |
701 | ||
702 | if (!inf->fn(addr, esr, regs)) | |
703 | return; | |
704 | ||
705 | pr_alert("Unhandled fault: %s (0x%08x) at 0x%016lx\n", | |
706 | inf->name, esr, addr); | |
707 | ||
708 | info.si_signo = inf->sig; | |
709 | info.si_errno = 0; | |
710 | info.si_code = inf->code; | |
711 | info.si_addr = (void __user *)addr; | |
712 | arm64_notify_die("", regs, &info, esr); | |
713 | } | |
714 | ||
715 | /* | |
716 | * Handle stack alignment exceptions. | |
717 | */ | |
718 | asmlinkage void __exception do_sp_pc_abort(unsigned long addr, | |
719 | unsigned int esr, | |
720 | struct pt_regs *regs) | |
721 | { | |
722 | struct siginfo info; | |
9e793ab8 VM |
723 | struct task_struct *tsk = current; |
724 | ||
725 | if (show_unhandled_signals && unhandled_signal(tsk, SIGBUS)) | |
726 | pr_info_ratelimited("%s[%d]: %s exception: pc=%p sp=%p\n", | |
727 | tsk->comm, task_pid_nr(tsk), | |
728 | esr_get_class_string(esr), (void *)regs->pc, | |
729 | (void *)regs->sp); | |
1d18c47c CM |
730 | |
731 | info.si_signo = SIGBUS; | |
732 | info.si_errno = 0; | |
733 | info.si_code = BUS_ADRALN; | |
734 | info.si_addr = (void __user *)addr; | |
9e793ab8 | 735 | arm64_notify_die("Oops - SP/PC alignment exception", regs, &info, esr); |
1d18c47c CM |
736 | } |
737 | ||
9fb7410f DM |
738 | int __init early_brk64(unsigned long addr, unsigned int esr, |
739 | struct pt_regs *regs); | |
740 | ||
741 | /* | |
742 | * __refdata because early_brk64 is __init, but the reference to it is | |
743 | * clobbered at arch_initcall time. | |
744 | * See traps.c and debug-monitors.c:debug_traps_init(). | |
745 | */ | |
746 | static struct fault_info __refdata debug_fault_info[] = { | |
1d18c47c CM |
747 | { do_bad, SIGTRAP, TRAP_HWBKPT, "hardware breakpoint" }, |
748 | { do_bad, SIGTRAP, TRAP_HWBKPT, "hardware single-step" }, | |
749 | { do_bad, SIGTRAP, TRAP_HWBKPT, "hardware watchpoint" }, | |
750 | { do_bad, SIGBUS, 0, "unknown 3" }, | |
751 | { do_bad, SIGTRAP, TRAP_BRKPT, "aarch32 BKPT" }, | |
752 | { do_bad, SIGTRAP, 0, "aarch32 vector catch" }, | |
9fb7410f | 753 | { early_brk64, SIGTRAP, TRAP_BRKPT, "aarch64 BRK" }, |
1d18c47c CM |
754 | { do_bad, SIGBUS, 0, "unknown 7" }, |
755 | }; | |
756 | ||
757 | void __init hook_debug_fault_code(int nr, | |
758 | int (*fn)(unsigned long, unsigned int, struct pt_regs *), | |
759 | int sig, int code, const char *name) | |
760 | { | |
761 | BUG_ON(nr < 0 || nr >= ARRAY_SIZE(debug_fault_info)); | |
762 | ||
763 | debug_fault_info[nr].fn = fn; | |
764 | debug_fault_info[nr].sig = sig; | |
765 | debug_fault_info[nr].code = code; | |
766 | debug_fault_info[nr].name = name; | |
767 | } | |
768 | ||
769 | asmlinkage int __exception do_debug_exception(unsigned long addr, | |
770 | unsigned int esr, | |
771 | struct pt_regs *regs) | |
772 | { | |
773 | const struct fault_info *inf = debug_fault_info + DBG_ESR_EVT(esr); | |
774 | struct siginfo info; | |
6afedcd2 | 775 | int rv; |
1d18c47c | 776 | |
6afedcd2 JM |
777 | /* |
778 | * Tell lockdep we disabled irqs in entry.S. Do nothing if they were | |
779 | * already disabled to preserve the last enabled/disabled addresses. | |
780 | */ | |
781 | if (interrupts_enabled(regs)) | |
782 | trace_hardirqs_off(); | |
1d18c47c | 783 | |
6afedcd2 JM |
784 | if (!inf->fn(addr, esr, regs)) { |
785 | rv = 1; | |
786 | } else { | |
787 | pr_alert("Unhandled debug exception: %s (0x%08x) at 0x%016lx\n", | |
788 | inf->name, esr, addr); | |
789 | ||
790 | info.si_signo = inf->sig; | |
791 | info.si_errno = 0; | |
792 | info.si_code = inf->code; | |
793 | info.si_addr = (void __user *)addr; | |
794 | arm64_notify_die("", regs, &info, 0); | |
795 | rv = 0; | |
796 | } | |
1d18c47c | 797 | |
6afedcd2 JM |
798 | if (interrupts_enabled(regs)) |
799 | trace_hardirqs_on(); | |
1d18c47c | 800 | |
6afedcd2 | 801 | return rv; |
1d18c47c | 802 | } |
2dd0e8d2 | 803 | NOKPROBE_SYMBOL(do_debug_exception); |
338d4f49 JM |
804 | |
805 | #ifdef CONFIG_ARM64_PAN | |
2a6dcb2b | 806 | int cpu_enable_pan(void *__unused) |
338d4f49 | 807 | { |
7209c868 JM |
808 | /* |
809 | * We modify PSTATE. This won't work from irq context as the PSTATE | |
810 | * is discarded once we return from the exception. | |
811 | */ | |
812 | WARN_ON_ONCE(in_interrupt()); | |
813 | ||
338d4f49 | 814 | config_sctlr_el1(SCTLR_EL1_SPAN, 0); |
7209c868 | 815 | asm(SET_PSTATE_PAN(1)); |
2a6dcb2b | 816 | return 0; |
338d4f49 JM |
817 | } |
818 | #endif /* CONFIG_ARM64_PAN */ |