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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> |
3bbf7157 | 37 | #include <asm/cmpxchg.h> |
338d4f49 | 38 | #include <asm/cpufeature.h> |
1d18c47c CM |
39 | #include <asm/exception.h> |
40 | #include <asm/debug-monitors.h> | |
9141300a | 41 | #include <asm/esr.h> |
338d4f49 | 42 | #include <asm/sysreg.h> |
1d18c47c CM |
43 | #include <asm/system_misc.h> |
44 | #include <asm/pgtable.h> | |
45 | #include <asm/tlbflush.h> | |
46 | ||
7edda088 TB |
47 | #include <acpi/ghes.h> |
48 | ||
09a6adf5 VK |
49 | struct fault_info { |
50 | int (*fn)(unsigned long addr, unsigned int esr, | |
51 | struct pt_regs *regs); | |
52 | int sig; | |
53 | int code; | |
54 | const char *name; | |
55 | }; | |
56 | ||
57 | static const struct fault_info fault_info[]; | |
58 | ||
59 | static inline const struct fault_info *esr_to_fault_info(unsigned int esr) | |
60 | { | |
61 | return fault_info + (esr & 63); | |
62 | } | |
3495386b | 63 | |
2dd0e8d2 SP |
64 | #ifdef CONFIG_KPROBES |
65 | static inline int notify_page_fault(struct pt_regs *regs, unsigned int esr) | |
66 | { | |
67 | int ret = 0; | |
68 | ||
69 | /* kprobe_running() needs smp_processor_id() */ | |
70 | if (!user_mode(regs)) { | |
71 | preempt_disable(); | |
72 | if (kprobe_running() && kprobe_fault_handler(regs, esr)) | |
73 | ret = 1; | |
74 | preempt_enable(); | |
75 | } | |
76 | ||
77 | return ret; | |
78 | } | |
79 | #else | |
80 | static inline int notify_page_fault(struct pt_regs *regs, unsigned int esr) | |
81 | { | |
82 | return 0; | |
83 | } | |
84 | #endif | |
85 | ||
1f9b8936 JT |
86 | static void data_abort_decode(unsigned int esr) |
87 | { | |
88 | pr_alert("Data abort info:\n"); | |
89 | ||
90 | if (esr & ESR_ELx_ISV) { | |
91 | pr_alert(" Access size = %u byte(s)\n", | |
92 | 1U << ((esr & ESR_ELx_SAS) >> ESR_ELx_SAS_SHIFT)); | |
93 | pr_alert(" SSE = %lu, SRT = %lu\n", | |
94 | (esr & ESR_ELx_SSE) >> ESR_ELx_SSE_SHIFT, | |
95 | (esr & ESR_ELx_SRT_MASK) >> ESR_ELx_SRT_SHIFT); | |
96 | pr_alert(" SF = %lu, AR = %lu\n", | |
97 | (esr & ESR_ELx_SF) >> ESR_ELx_SF_SHIFT, | |
98 | (esr & ESR_ELx_AR) >> ESR_ELx_AR_SHIFT); | |
99 | } else { | |
100 | pr_alert(" ISV = 0, ISS = 0x%08lu\n", esr & ESR_ELx_ISS_MASK); | |
101 | } | |
102 | ||
103 | pr_alert(" CM = %lu, WnR = %lu\n", | |
104 | (esr & ESR_ELx_CM) >> ESR_ELx_CM_SHIFT, | |
105 | (esr & ESR_ELx_WNR) >> ESR_ELx_WNR_SHIFT); | |
106 | } | |
107 | ||
108 | /* | |
109 | * Decode mem abort information | |
110 | */ | |
111 | static void mem_abort_decode(unsigned int esr) | |
112 | { | |
113 | pr_alert("Mem abort info:\n"); | |
114 | ||
115 | pr_alert(" Exception class = %s, IL = %u bits\n", | |
116 | esr_get_class_string(esr), | |
117 | (esr & ESR_ELx_IL) ? 32 : 16); | |
118 | pr_alert(" SET = %lu, FnV = %lu\n", | |
119 | (esr & ESR_ELx_SET_MASK) >> ESR_ELx_SET_SHIFT, | |
120 | (esr & ESR_ELx_FnV) >> ESR_ELx_FnV_SHIFT); | |
121 | pr_alert(" EA = %lu, S1PTW = %lu\n", | |
122 | (esr & ESR_ELx_EA) >> ESR_ELx_EA_SHIFT, | |
123 | (esr & ESR_ELx_S1PTW) >> ESR_ELx_S1PTW_SHIFT); | |
124 | ||
125 | if (esr_is_data_abort(esr)) | |
126 | data_abort_decode(esr); | |
127 | } | |
128 | ||
1d18c47c | 129 | /* |
67ce16ec | 130 | * Dump out the page tables associated with 'addr' in the currently active mm. |
1d18c47c | 131 | */ |
67ce16ec | 132 | void show_pte(unsigned long addr) |
1d18c47c | 133 | { |
67ce16ec | 134 | struct mm_struct *mm; |
1d18c47c CM |
135 | pgd_t *pgd; |
136 | ||
67ce16ec KM |
137 | if (addr < TASK_SIZE) { |
138 | /* TTBR0 */ | |
139 | mm = current->active_mm; | |
140 | if (mm == &init_mm) { | |
141 | pr_alert("[%016lx] user address but active_mm is swapper\n", | |
142 | addr); | |
143 | return; | |
144 | } | |
145 | } else if (addr >= VA_START) { | |
146 | /* TTBR1 */ | |
1d18c47c | 147 | mm = &init_mm; |
67ce16ec KM |
148 | } else { |
149 | pr_alert("[%016lx] address between user and kernel address ranges\n", | |
150 | addr); | |
151 | return; | |
152 | } | |
1d18c47c | 153 | |
1eb34b6e WD |
154 | pr_alert("%s pgtable: %luk pages, %u-bit VAs, pgd = %p\n", |
155 | mm == &init_mm ? "swapper" : "user", PAGE_SIZE / SZ_1K, | |
156 | VA_BITS, mm->pgd); | |
1d18c47c | 157 | pgd = pgd_offset(mm, addr); |
67ce16ec | 158 | pr_alert("[%016lx] *pgd=%016llx", addr, pgd_val(*pgd)); |
1d18c47c CM |
159 | |
160 | do { | |
161 | pud_t *pud; | |
162 | pmd_t *pmd; | |
163 | pte_t *pte; | |
164 | ||
4339e3f3 | 165 | if (pgd_none(*pgd) || pgd_bad(*pgd)) |
1d18c47c CM |
166 | break; |
167 | ||
168 | pud = pud_offset(pgd, addr); | |
6ef4fb38 | 169 | pr_cont(", *pud=%016llx", pud_val(*pud)); |
4339e3f3 | 170 | if (pud_none(*pud) || pud_bad(*pud)) |
1d18c47c CM |
171 | break; |
172 | ||
173 | pmd = pmd_offset(pud, addr); | |
6ef4fb38 | 174 | pr_cont(", *pmd=%016llx", pmd_val(*pmd)); |
4339e3f3 | 175 | if (pmd_none(*pmd) || pmd_bad(*pmd)) |
1d18c47c CM |
176 | break; |
177 | ||
178 | pte = pte_offset_map(pmd, addr); | |
6ef4fb38 | 179 | pr_cont(", *pte=%016llx", pte_val(*pte)); |
1d18c47c CM |
180 | pte_unmap(pte); |
181 | } while(0); | |
182 | ||
6ef4fb38 | 183 | pr_cont("\n"); |
1d18c47c CM |
184 | } |
185 | ||
66dbd6e6 CM |
186 | /* |
187 | * This function sets the access flags (dirty, accessed), as well as write | |
188 | * permission, and only to a more permissive setting. | |
189 | * | |
190 | * It needs to cope with hardware update of the accessed/dirty state by other | |
191 | * agents in the system and can safely skip the __sync_icache_dcache() call as, | |
192 | * like set_pte_at(), the PTE is never changed from no-exec to exec here. | |
193 | * | |
194 | * Returns whether or not the PTE actually changed. | |
195 | */ | |
196 | int ptep_set_access_flags(struct vm_area_struct *vma, | |
197 | unsigned long address, pte_t *ptep, | |
198 | pte_t entry, int dirty) | |
199 | { | |
3bbf7157 | 200 | pteval_t old_pteval, pteval; |
66dbd6e6 CM |
201 | |
202 | if (pte_same(*ptep, entry)) | |
203 | return 0; | |
204 | ||
205 | /* only preserve the access flags and write permission */ | |
73e86cb0 | 206 | pte_val(entry) &= PTE_RDONLY | PTE_AF | PTE_WRITE | PTE_DIRTY; |
66dbd6e6 CM |
207 | |
208 | /* | |
209 | * Setting the flags must be done atomically to avoid racing with the | |
6d332747 CM |
210 | * hardware update of the access/dirty state. The PTE_RDONLY bit must |
211 | * be set to the most permissive (lowest value) of *ptep and entry | |
212 | * (calculated as: a & b == ~(~a | ~b)). | |
66dbd6e6 | 213 | */ |
6d332747 | 214 | pte_val(entry) ^= PTE_RDONLY; |
3bbf7157 CM |
215 | pteval = READ_ONCE(pte_val(*ptep)); |
216 | do { | |
217 | old_pteval = pteval; | |
218 | pteval ^= PTE_RDONLY; | |
219 | pteval |= pte_val(entry); | |
220 | pteval ^= PTE_RDONLY; | |
221 | pteval = cmpxchg_relaxed(&pte_val(*ptep), old_pteval, pteval); | |
222 | } while (pteval != old_pteval); | |
66dbd6e6 CM |
223 | |
224 | flush_tlb_fix_spurious_fault(vma, address); | |
225 | return 1; | |
226 | } | |
66dbd6e6 | 227 | |
9adeb8e7 LA |
228 | static bool is_el1_instruction_abort(unsigned int esr) |
229 | { | |
230 | return ESR_ELx_EC(esr) == ESR_ELx_EC_IABT_CUR; | |
231 | } | |
232 | ||
b824b930 SB |
233 | static inline bool is_permission_fault(unsigned int esr, struct pt_regs *regs, |
234 | unsigned long addr) | |
235 | { | |
236 | unsigned int ec = ESR_ELx_EC(esr); | |
237 | unsigned int fsc_type = esr & ESR_ELx_FSC_TYPE; | |
238 | ||
239 | if (ec != ESR_ELx_EC_DABT_CUR && ec != ESR_ELx_EC_IABT_CUR) | |
240 | return false; | |
241 | ||
242 | if (fsc_type == ESR_ELx_FSC_PERM) | |
243 | return true; | |
244 | ||
245 | if (addr < USER_DS && system_uses_ttbr0_pan()) | |
246 | return fsc_type == ESR_ELx_FSC_FAULT && | |
247 | (regs->pstate & PSR_PAN_BIT); | |
248 | ||
249 | return false; | |
250 | } | |
251 | ||
1d18c47c CM |
252 | /* |
253 | * The kernel tried to access some page that wasn't present. | |
254 | */ | |
67ce16ec KM |
255 | static void __do_kernel_fault(unsigned long addr, unsigned int esr, |
256 | struct pt_regs *regs) | |
1d18c47c | 257 | { |
b824b930 SB |
258 | const char *msg; |
259 | ||
1d18c47c CM |
260 | /* |
261 | * Are we prepared to handle this kernel fault? | |
9adeb8e7 | 262 | * We are almost certainly not prepared to handle instruction faults. |
1d18c47c | 263 | */ |
9adeb8e7 | 264 | if (!is_el1_instruction_abort(esr) && fixup_exception(regs)) |
1d18c47c CM |
265 | return; |
266 | ||
267 | /* | |
268 | * No handler, we'll have to terminate things with extreme prejudice. | |
269 | */ | |
270 | bust_spinlocks(1); | |
b824b930 SB |
271 | |
272 | if (is_permission_fault(esr, regs, addr)) { | |
273 | if (esr & ESR_ELx_WNR) | |
274 | msg = "write to read-only memory"; | |
275 | else | |
276 | msg = "read from unreadable memory"; | |
277 | } else if (addr < PAGE_SIZE) { | |
278 | msg = "NULL pointer dereference"; | |
279 | } else { | |
280 | msg = "paging request"; | |
281 | } | |
282 | ||
283 | pr_alert("Unable to handle kernel %s at virtual address %08lx\n", msg, | |
284 | addr); | |
1d18c47c | 285 | |
1f9b8936 JT |
286 | mem_abort_decode(esr); |
287 | ||
67ce16ec | 288 | show_pte(addr); |
1d18c47c CM |
289 | die("Oops", regs, esr); |
290 | bust_spinlocks(0); | |
291 | do_exit(SIGKILL); | |
292 | } | |
293 | ||
294 | /* | |
295 | * Something tried to access memory that isn't in our memory map. User mode | |
296 | * accesses just cause a SIGSEGV | |
297 | */ | |
298 | static void __do_user_fault(struct task_struct *tsk, unsigned long addr, | |
299 | unsigned int esr, unsigned int sig, int code, | |
e7c600f1 | 300 | struct pt_regs *regs, int fault) |
1d18c47c CM |
301 | { |
302 | struct siginfo si; | |
09a6adf5 | 303 | const struct fault_info *inf; |
e7c600f1 | 304 | unsigned int lsb = 0; |
1d18c47c | 305 | |
f871d268 | 306 | if (unhandled_signal(tsk, sig) && show_unhandled_signals_ratelimited()) { |
09a6adf5 | 307 | inf = esr_to_fault_info(esr); |
83016b20 | 308 | pr_info("%s[%d]: unhandled %s (%d) at 0x%08lx, esr 0x%03x", |
09a6adf5 | 309 | tsk->comm, task_pid_nr(tsk), inf->name, sig, |
3495386b | 310 | addr, esr); |
83016b20 KM |
311 | print_vma_addr(KERN_CONT ", in ", regs->pc); |
312 | pr_cont("\n"); | |
c07ab957 | 313 | __show_regs(regs); |
1d18c47c CM |
314 | } |
315 | ||
316 | tsk->thread.fault_address = addr; | |
9141300a | 317 | tsk->thread.fault_code = esr; |
1d18c47c CM |
318 | si.si_signo = sig; |
319 | si.si_errno = 0; | |
320 | si.si_code = code; | |
321 | si.si_addr = (void __user *)addr; | |
e7c600f1 JZZ |
322 | /* |
323 | * Either small page or large page may be poisoned. | |
324 | * In other words, VM_FAULT_HWPOISON_LARGE and | |
325 | * VM_FAULT_HWPOISON are mutually exclusive. | |
326 | */ | |
327 | if (fault & VM_FAULT_HWPOISON_LARGE) | |
328 | lsb = hstate_index_to_shift(VM_FAULT_GET_HINDEX(fault)); | |
329 | else if (fault & VM_FAULT_HWPOISON) | |
330 | lsb = PAGE_SHIFT; | |
331 | si.si_addr_lsb = lsb; | |
332 | ||
1d18c47c CM |
333 | force_sig_info(sig, &si, tsk); |
334 | } | |
335 | ||
59f67e16 | 336 | static void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *regs) |
1d18c47c CM |
337 | { |
338 | struct task_struct *tsk = current; | |
09a6adf5 | 339 | const struct fault_info *inf; |
1d18c47c CM |
340 | |
341 | /* | |
342 | * If we are in kernel mode at this point, we have no context to | |
343 | * handle this fault with. | |
344 | */ | |
09a6adf5 VK |
345 | if (user_mode(regs)) { |
346 | inf = esr_to_fault_info(esr); | |
e7c600f1 | 347 | __do_user_fault(tsk, addr, esr, inf->sig, inf->code, regs, 0); |
09a6adf5 | 348 | } else |
67ce16ec | 349 | __do_kernel_fault(addr, esr, regs); |
1d18c47c CM |
350 | } |
351 | ||
352 | #define VM_FAULT_BADMAP 0x010000 | |
353 | #define VM_FAULT_BADACCESS 0x020000 | |
354 | ||
1d18c47c | 355 | static int __do_page_fault(struct mm_struct *mm, unsigned long addr, |
db6f4106 | 356 | unsigned int mm_flags, unsigned long vm_flags, |
1d18c47c CM |
357 | struct task_struct *tsk) |
358 | { | |
359 | struct vm_area_struct *vma; | |
360 | int fault; | |
361 | ||
362 | vma = find_vma(mm, addr); | |
363 | fault = VM_FAULT_BADMAP; | |
364 | if (unlikely(!vma)) | |
365 | goto out; | |
366 | if (unlikely(vma->vm_start > addr)) | |
367 | goto check_stack; | |
368 | ||
369 | /* | |
370 | * Ok, we have a good vm_area for this memory access, so we can handle | |
371 | * it. | |
372 | */ | |
373 | good_area: | |
db6f4106 WD |
374 | /* |
375 | * Check that the permissions on the VMA allow for the fault which | |
cab15ce6 | 376 | * occurred. |
db6f4106 WD |
377 | */ |
378 | if (!(vma->vm_flags & vm_flags)) { | |
1d18c47c CM |
379 | fault = VM_FAULT_BADACCESS; |
380 | goto out; | |
381 | } | |
382 | ||
dcddffd4 | 383 | return handle_mm_fault(vma, addr & PAGE_MASK, mm_flags); |
1d18c47c CM |
384 | |
385 | check_stack: | |
386 | if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr)) | |
387 | goto good_area; | |
388 | out: | |
389 | return fault; | |
390 | } | |
391 | ||
541ec870 MR |
392 | static bool is_el0_instruction_abort(unsigned int esr) |
393 | { | |
394 | return ESR_ELx_EC(esr) == ESR_ELx_EC_IABT_LOW; | |
395 | } | |
396 | ||
1d18c47c CM |
397 | static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, |
398 | struct pt_regs *regs) | |
399 | { | |
400 | struct task_struct *tsk; | |
401 | struct mm_struct *mm; | |
0e3a9026 | 402 | int fault, sig, code, major = 0; |
cab15ce6 | 403 | unsigned long vm_flags = VM_READ | VM_WRITE; |
db6f4106 WD |
404 | unsigned int mm_flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; |
405 | ||
2dd0e8d2 SP |
406 | if (notify_page_fault(regs, esr)) |
407 | return 0; | |
408 | ||
1d18c47c CM |
409 | tsk = current; |
410 | mm = tsk->mm; | |
411 | ||
1d18c47c CM |
412 | /* |
413 | * If we're in an interrupt or have no user context, we must not take | |
414 | * the fault. | |
415 | */ | |
70ffdb93 | 416 | if (faulthandler_disabled() || !mm) |
1d18c47c CM |
417 | goto no_context; |
418 | ||
759496ba JW |
419 | if (user_mode(regs)) |
420 | mm_flags |= FAULT_FLAG_USER; | |
421 | ||
541ec870 | 422 | if (is_el0_instruction_abort(esr)) { |
759496ba | 423 | vm_flags = VM_EXEC; |
aed40e01 | 424 | } else if ((esr & ESR_ELx_WNR) && !(esr & ESR_ELx_CM)) { |
759496ba JW |
425 | vm_flags = VM_WRITE; |
426 | mm_flags |= FAULT_FLAG_WRITE; | |
427 | } | |
428 | ||
b824b930 | 429 | if (addr < USER_DS && is_permission_fault(esr, regs, addr)) { |
e19a6ee2 JM |
430 | /* regs->orig_addr_limit may be 0 if we entered from EL0 */ |
431 | if (regs->orig_addr_limit == KERNEL_DS) | |
70c8abc2 | 432 | die("Accessing user space memory with fs=KERNEL_DS", regs, esr); |
70544196 | 433 | |
9adeb8e7 LA |
434 | if (is_el1_instruction_abort(esr)) |
435 | die("Attempting to execute userspace memory", regs, esr); | |
436 | ||
57f4959b | 437 | if (!search_exception_tables(regs->pc)) |
70c8abc2 | 438 | die("Accessing user space memory outside uaccess.h routines", regs, esr); |
57f4959b | 439 | } |
338d4f49 | 440 | |
0e3a9026 PA |
441 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr); |
442 | ||
1d18c47c CM |
443 | /* |
444 | * As per x86, we may deadlock here. However, since the kernel only | |
445 | * validly references user space from well defined areas of the code, | |
446 | * we can bug out early if this is from code which shouldn't. | |
447 | */ | |
448 | if (!down_read_trylock(&mm->mmap_sem)) { | |
449 | if (!user_mode(regs) && !search_exception_tables(regs->pc)) | |
450 | goto no_context; | |
451 | retry: | |
452 | down_read(&mm->mmap_sem); | |
453 | } else { | |
454 | /* | |
455 | * The above down_read_trylock() might have succeeded in which | |
456 | * case, we'll have missed the might_sleep() from down_read(). | |
457 | */ | |
458 | might_sleep(); | |
459 | #ifdef CONFIG_DEBUG_VM | |
460 | if (!user_mode(regs) && !search_exception_tables(regs->pc)) | |
461 | goto no_context; | |
462 | #endif | |
463 | } | |
464 | ||
db6f4106 | 465 | fault = __do_page_fault(mm, addr, mm_flags, vm_flags, tsk); |
0e3a9026 | 466 | major |= fault & VM_FAULT_MAJOR; |
1d18c47c | 467 | |
0e3a9026 PA |
468 | if (fault & VM_FAULT_RETRY) { |
469 | /* | |
470 | * If we need to retry but a fatal signal is pending, | |
471 | * handle the signal first. We do not need to release | |
472 | * the mmap_sem because it would already be released | |
473 | * in __lock_page_or_retry in mm/filemap.c. | |
474 | */ | |
289d07a2 MR |
475 | if (fatal_signal_pending(current)) { |
476 | if (!user_mode(regs)) | |
477 | goto no_context; | |
0e3a9026 | 478 | return 0; |
289d07a2 | 479 | } |
0e3a9026 PA |
480 | |
481 | /* | |
482 | * Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk of | |
483 | * starvation. | |
484 | */ | |
485 | if (mm_flags & FAULT_FLAG_ALLOW_RETRY) { | |
486 | mm_flags &= ~FAULT_FLAG_ALLOW_RETRY; | |
487 | mm_flags |= FAULT_FLAG_TRIED; | |
488 | goto retry; | |
489 | } | |
490 | } | |
491 | up_read(&mm->mmap_sem); | |
1d18c47c CM |
492 | |
493 | /* | |
0e3a9026 | 494 | * Handle the "normal" (no error) case first. |
1d18c47c | 495 | */ |
0e3a9026 PA |
496 | if (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP | |
497 | VM_FAULT_BADACCESS)))) { | |
498 | /* | |
499 | * Major/minor page fault accounting is only done | |
500 | * once. If we go through a retry, it is extremely | |
501 | * likely that the page will be found in page cache at | |
502 | * that point. | |
503 | */ | |
504 | if (major) { | |
1d18c47c CM |
505 | tsk->maj_flt++; |
506 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, | |
507 | addr); | |
508 | } else { | |
509 | tsk->min_flt++; | |
510 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, | |
511 | addr); | |
512 | } | |
1d18c47c | 513 | |
1d18c47c | 514 | return 0; |
0e3a9026 | 515 | } |
1d18c47c | 516 | |
87134102 JW |
517 | /* |
518 | * If we are in kernel mode at this point, we have no context to | |
519 | * handle this fault with. | |
520 | */ | |
521 | if (!user_mode(regs)) | |
522 | goto no_context; | |
523 | ||
1d18c47c CM |
524 | if (fault & VM_FAULT_OOM) { |
525 | /* | |
526 | * We ran out of memory, call the OOM killer, and return to | |
527 | * userspace (which will retry the fault, or kill us if we got | |
528 | * oom-killed). | |
529 | */ | |
530 | pagefault_out_of_memory(); | |
531 | return 0; | |
532 | } | |
533 | ||
1d18c47c CM |
534 | if (fault & VM_FAULT_SIGBUS) { |
535 | /* | |
536 | * We had some memory, but were unable to successfully fix up | |
537 | * this page fault. | |
538 | */ | |
539 | sig = SIGBUS; | |
540 | code = BUS_ADRERR; | |
e7c600f1 JZZ |
541 | } else if (fault & (VM_FAULT_HWPOISON | VM_FAULT_HWPOISON_LARGE)) { |
542 | sig = SIGBUS; | |
543 | code = BUS_MCEERR_AR; | |
1d18c47c CM |
544 | } else { |
545 | /* | |
546 | * Something tried to access memory that isn't in our memory | |
547 | * map. | |
548 | */ | |
549 | sig = SIGSEGV; | |
550 | code = fault == VM_FAULT_BADACCESS ? | |
551 | SEGV_ACCERR : SEGV_MAPERR; | |
552 | } | |
553 | ||
e7c600f1 | 554 | __do_user_fault(tsk, addr, esr, sig, code, regs, fault); |
1d18c47c CM |
555 | return 0; |
556 | ||
557 | no_context: | |
67ce16ec | 558 | __do_kernel_fault(addr, esr, regs); |
1d18c47c CM |
559 | return 0; |
560 | } | |
561 | ||
562 | /* | |
563 | * First Level Translation Fault Handler | |
564 | * | |
565 | * We enter here because the first level page table doesn't contain a valid | |
566 | * entry for the address. | |
567 | * | |
568 | * If the address is in kernel space (>= TASK_SIZE), then we are probably | |
569 | * faulting in the vmalloc() area. | |
570 | * | |
571 | * If the init_task's first level page tables contains the relevant entry, we | |
572 | * copy the it to this task. If not, we send the process a signal, fixup the | |
573 | * exception, or oops the kernel. | |
574 | * | |
575 | * NOTE! We MUST NOT take any locks for this case. We may be in an interrupt | |
576 | * or a critical region, and should only copy the information from the master | |
577 | * page table, nothing more. | |
578 | */ | |
579 | static int __kprobes do_translation_fault(unsigned long addr, | |
580 | unsigned int esr, | |
581 | struct pt_regs *regs) | |
582 | { | |
583 | if (addr < TASK_SIZE) | |
584 | return do_page_fault(addr, esr, regs); | |
585 | ||
586 | do_bad_area(addr, esr, regs); | |
587 | return 0; | |
588 | } | |
589 | ||
52d7523d EL |
590 | static int do_alignment_fault(unsigned long addr, unsigned int esr, |
591 | struct pt_regs *regs) | |
592 | { | |
593 | do_bad_area(addr, esr, regs); | |
594 | return 0; | |
595 | } | |
596 | ||
1d18c47c CM |
597 | /* |
598 | * This abort handler always returns "fault". | |
599 | */ | |
600 | static int do_bad(unsigned long addr, unsigned int esr, struct pt_regs *regs) | |
601 | { | |
602 | return 1; | |
603 | } | |
604 | ||
32015c23 TB |
605 | /* |
606 | * This abort handler deals with Synchronous External Abort. | |
607 | * It calls notifiers, and then returns "fault". | |
608 | */ | |
609 | static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs) | |
610 | { | |
611 | struct siginfo info; | |
612 | const struct fault_info *inf; | |
621f48e4 | 613 | int ret = 0; |
32015c23 TB |
614 | |
615 | inf = esr_to_fault_info(esr); | |
616 | pr_err("Synchronous External Abort: %s (0x%08x) at 0x%016lx\n", | |
617 | inf->name, esr, addr); | |
618 | ||
7edda088 TB |
619 | /* |
620 | * Synchronous aborts may interrupt code which had interrupts masked. | |
621 | * Before calling out into the wider kernel tell the interested | |
622 | * subsystems. | |
623 | */ | |
624 | if (IS_ENABLED(CONFIG_ACPI_APEI_SEA)) { | |
625 | if (interrupts_enabled(regs)) | |
626 | nmi_enter(); | |
627 | ||
621f48e4 | 628 | ret = ghes_notify_sea(); |
7edda088 TB |
629 | |
630 | if (interrupts_enabled(regs)) | |
631 | nmi_exit(); | |
632 | } | |
633 | ||
32015c23 TB |
634 | info.si_signo = SIGBUS; |
635 | info.si_errno = 0; | |
636 | info.si_code = 0; | |
637 | if (esr & ESR_ELx_FnV) | |
638 | info.si_addr = NULL; | |
639 | else | |
640 | info.si_addr = (void __user *)addr; | |
641 | arm64_notify_die("", regs, &info, esr); | |
642 | ||
621f48e4 | 643 | return ret; |
32015c23 TB |
644 | } |
645 | ||
09a6adf5 | 646 | static const struct fault_info fault_info[] = { |
1d18c47c CM |
647 | { do_bad, SIGBUS, 0, "ttbr address size fault" }, |
648 | { do_bad, SIGBUS, 0, "level 1 address size fault" }, | |
649 | { do_bad, SIGBUS, 0, "level 2 address size fault" }, | |
650 | { do_bad, SIGBUS, 0, "level 3 address size fault" }, | |
7f73f7ae | 651 | { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 0 translation fault" }, |
1d18c47c CM |
652 | { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 1 translation fault" }, |
653 | { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 2 translation fault" }, | |
760bfb47 | 654 | { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 3 translation fault" }, |
c03784ee | 655 | { do_bad, SIGBUS, 0, "unknown 8" }, |
084bd298 SC |
656 | { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 1 access flag fault" }, |
657 | { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 2 access flag fault" }, | |
1d18c47c | 658 | { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 3 access flag fault" }, |
c03784ee | 659 | { do_bad, SIGBUS, 0, "unknown 12" }, |
084bd298 SC |
660 | { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 1 permission fault" }, |
661 | { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 2 permission fault" }, | |
1d18c47c | 662 | { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 3 permission fault" }, |
32015c23 | 663 | { do_sea, SIGBUS, 0, "synchronous external abort" }, |
c03784ee | 664 | { do_bad, SIGBUS, 0, "unknown 17" }, |
1d18c47c CM |
665 | { do_bad, SIGBUS, 0, "unknown 18" }, |
666 | { do_bad, SIGBUS, 0, "unknown 19" }, | |
32015c23 TB |
667 | { do_sea, SIGBUS, 0, "level 0 (translation table walk)" }, |
668 | { do_sea, SIGBUS, 0, "level 1 (translation table walk)" }, | |
669 | { do_sea, SIGBUS, 0, "level 2 (translation table walk)" }, | |
670 | { do_sea, SIGBUS, 0, "level 3 (translation table walk)" }, | |
671 | { do_sea, SIGBUS, 0, "synchronous parity or ECC error" }, | |
c03784ee | 672 | { do_bad, SIGBUS, 0, "unknown 25" }, |
1d18c47c CM |
673 | { do_bad, SIGBUS, 0, "unknown 26" }, |
674 | { do_bad, SIGBUS, 0, "unknown 27" }, | |
32015c23 TB |
675 | { do_sea, SIGBUS, 0, "level 0 synchronous parity error (translation table walk)" }, |
676 | { do_sea, SIGBUS, 0, "level 1 synchronous parity error (translation table walk)" }, | |
677 | { do_sea, SIGBUS, 0, "level 2 synchronous parity error (translation table walk)" }, | |
678 | { do_sea, SIGBUS, 0, "level 3 synchronous parity error (translation table walk)" }, | |
1d18c47c | 679 | { do_bad, SIGBUS, 0, "unknown 32" }, |
52d7523d | 680 | { do_alignment_fault, SIGBUS, BUS_ADRALN, "alignment fault" }, |
c03784ee | 681 | { do_bad, SIGBUS, 0, "unknown 34" }, |
1d18c47c CM |
682 | { do_bad, SIGBUS, 0, "unknown 35" }, |
683 | { do_bad, SIGBUS, 0, "unknown 36" }, | |
684 | { do_bad, SIGBUS, 0, "unknown 37" }, | |
685 | { do_bad, SIGBUS, 0, "unknown 38" }, | |
686 | { do_bad, SIGBUS, 0, "unknown 39" }, | |
687 | { do_bad, SIGBUS, 0, "unknown 40" }, | |
688 | { do_bad, SIGBUS, 0, "unknown 41" }, | |
689 | { do_bad, SIGBUS, 0, "unknown 42" }, | |
690 | { do_bad, SIGBUS, 0, "unknown 43" }, | |
691 | { do_bad, SIGBUS, 0, "unknown 44" }, | |
692 | { do_bad, SIGBUS, 0, "unknown 45" }, | |
693 | { do_bad, SIGBUS, 0, "unknown 46" }, | |
694 | { do_bad, SIGBUS, 0, "unknown 47" }, | |
c03784ee | 695 | { do_bad, SIGBUS, 0, "TLB conflict abort" }, |
1d18c47c CM |
696 | { do_bad, SIGBUS, 0, "unknown 49" }, |
697 | { do_bad, SIGBUS, 0, "unknown 50" }, | |
698 | { do_bad, SIGBUS, 0, "unknown 51" }, | |
699 | { do_bad, SIGBUS, 0, "implementation fault (lockdown abort)" }, | |
c03784ee | 700 | { do_bad, SIGBUS, 0, "implementation fault (unsupported exclusive)" }, |
1d18c47c CM |
701 | { do_bad, SIGBUS, 0, "unknown 54" }, |
702 | { do_bad, SIGBUS, 0, "unknown 55" }, | |
703 | { do_bad, SIGBUS, 0, "unknown 56" }, | |
704 | { do_bad, SIGBUS, 0, "unknown 57" }, | |
c03784ee | 705 | { do_bad, SIGBUS, 0, "unknown 58" }, |
1d18c47c CM |
706 | { do_bad, SIGBUS, 0, "unknown 59" }, |
707 | { do_bad, SIGBUS, 0, "unknown 60" }, | |
c03784ee MR |
708 | { do_bad, SIGBUS, 0, "section domain fault" }, |
709 | { do_bad, SIGBUS, 0, "page domain fault" }, | |
1d18c47c CM |
710 | { do_bad, SIGBUS, 0, "unknown 63" }, |
711 | }; | |
712 | ||
621f48e4 TB |
713 | /* |
714 | * Handle Synchronous External Aborts that occur in a guest kernel. | |
715 | * | |
716 | * The return value will be zero if the SEA was successfully handled | |
717 | * and non-zero if there was an error processing the error or there was | |
718 | * no error to process. | |
719 | */ | |
720 | int handle_guest_sea(phys_addr_t addr, unsigned int esr) | |
721 | { | |
722 | int ret = -ENOENT; | |
723 | ||
724 | if (IS_ENABLED(CONFIG_ACPI_APEI_SEA)) | |
725 | ret = ghes_notify_sea(); | |
726 | ||
727 | return ret; | |
728 | } | |
729 | ||
1d18c47c CM |
730 | /* |
731 | * Dispatch a data abort to the relevant handler. | |
732 | */ | |
733 | asmlinkage void __exception do_mem_abort(unsigned long addr, unsigned int esr, | |
734 | struct pt_regs *regs) | |
735 | { | |
09a6adf5 | 736 | const struct fault_info *inf = esr_to_fault_info(esr); |
1d18c47c CM |
737 | struct siginfo info; |
738 | ||
739 | if (!inf->fn(addr, esr, regs)) | |
740 | return; | |
741 | ||
742 | pr_alert("Unhandled fault: %s (0x%08x) at 0x%016lx\n", | |
743 | inf->name, esr, addr); | |
744 | ||
1f9b8936 JT |
745 | mem_abort_decode(esr); |
746 | ||
1d18c47c CM |
747 | info.si_signo = inf->sig; |
748 | info.si_errno = 0; | |
749 | info.si_code = inf->code; | |
750 | info.si_addr = (void __user *)addr; | |
751 | arm64_notify_die("", regs, &info, esr); | |
752 | } | |
753 | ||
754 | /* | |
755 | * Handle stack alignment exceptions. | |
756 | */ | |
757 | asmlinkage void __exception do_sp_pc_abort(unsigned long addr, | |
758 | unsigned int esr, | |
759 | struct pt_regs *regs) | |
760 | { | |
761 | struct siginfo info; | |
9e793ab8 VM |
762 | struct task_struct *tsk = current; |
763 | ||
764 | if (show_unhandled_signals && unhandled_signal(tsk, SIGBUS)) | |
765 | pr_info_ratelimited("%s[%d]: %s exception: pc=%p sp=%p\n", | |
766 | tsk->comm, task_pid_nr(tsk), | |
767 | esr_get_class_string(esr), (void *)regs->pc, | |
768 | (void *)regs->sp); | |
1d18c47c CM |
769 | |
770 | info.si_signo = SIGBUS; | |
771 | info.si_errno = 0; | |
772 | info.si_code = BUS_ADRALN; | |
773 | info.si_addr = (void __user *)addr; | |
9e793ab8 | 774 | arm64_notify_die("Oops - SP/PC alignment exception", regs, &info, esr); |
1d18c47c CM |
775 | } |
776 | ||
9fb7410f DM |
777 | int __init early_brk64(unsigned long addr, unsigned int esr, |
778 | struct pt_regs *regs); | |
779 | ||
780 | /* | |
781 | * __refdata because early_brk64 is __init, but the reference to it is | |
782 | * clobbered at arch_initcall time. | |
783 | * See traps.c and debug-monitors.c:debug_traps_init(). | |
784 | */ | |
785 | static struct fault_info __refdata debug_fault_info[] = { | |
1d18c47c CM |
786 | { do_bad, SIGTRAP, TRAP_HWBKPT, "hardware breakpoint" }, |
787 | { do_bad, SIGTRAP, TRAP_HWBKPT, "hardware single-step" }, | |
788 | { do_bad, SIGTRAP, TRAP_HWBKPT, "hardware watchpoint" }, | |
789 | { do_bad, SIGBUS, 0, "unknown 3" }, | |
790 | { do_bad, SIGTRAP, TRAP_BRKPT, "aarch32 BKPT" }, | |
791 | { do_bad, SIGTRAP, 0, "aarch32 vector catch" }, | |
9fb7410f | 792 | { early_brk64, SIGTRAP, TRAP_BRKPT, "aarch64 BRK" }, |
1d18c47c CM |
793 | { do_bad, SIGBUS, 0, "unknown 7" }, |
794 | }; | |
795 | ||
796 | void __init hook_debug_fault_code(int nr, | |
797 | int (*fn)(unsigned long, unsigned int, struct pt_regs *), | |
798 | int sig, int code, const char *name) | |
799 | { | |
800 | BUG_ON(nr < 0 || nr >= ARRAY_SIZE(debug_fault_info)); | |
801 | ||
802 | debug_fault_info[nr].fn = fn; | |
803 | debug_fault_info[nr].sig = sig; | |
804 | debug_fault_info[nr].code = code; | |
805 | debug_fault_info[nr].name = name; | |
806 | } | |
807 | ||
808 | asmlinkage int __exception do_debug_exception(unsigned long addr, | |
809 | unsigned int esr, | |
810 | struct pt_regs *regs) | |
811 | { | |
812 | const struct fault_info *inf = debug_fault_info + DBG_ESR_EVT(esr); | |
813 | struct siginfo info; | |
6afedcd2 | 814 | int rv; |
1d18c47c | 815 | |
6afedcd2 JM |
816 | /* |
817 | * Tell lockdep we disabled irqs in entry.S. Do nothing if they were | |
818 | * already disabled to preserve the last enabled/disabled addresses. | |
819 | */ | |
820 | if (interrupts_enabled(regs)) | |
821 | trace_hardirqs_off(); | |
1d18c47c | 822 | |
6afedcd2 JM |
823 | if (!inf->fn(addr, esr, regs)) { |
824 | rv = 1; | |
825 | } else { | |
826 | pr_alert("Unhandled debug exception: %s (0x%08x) at 0x%016lx\n", | |
827 | inf->name, esr, addr); | |
828 | ||
829 | info.si_signo = inf->sig; | |
830 | info.si_errno = 0; | |
831 | info.si_code = inf->code; | |
832 | info.si_addr = (void __user *)addr; | |
833 | arm64_notify_die("", regs, &info, 0); | |
834 | rv = 0; | |
835 | } | |
1d18c47c | 836 | |
6afedcd2 JM |
837 | if (interrupts_enabled(regs)) |
838 | trace_hardirqs_on(); | |
1d18c47c | 839 | |
6afedcd2 | 840 | return rv; |
1d18c47c | 841 | } |
2dd0e8d2 | 842 | NOKPROBE_SYMBOL(do_debug_exception); |
338d4f49 JM |
843 | |
844 | #ifdef CONFIG_ARM64_PAN | |
2a6dcb2b | 845 | int cpu_enable_pan(void *__unused) |
338d4f49 | 846 | { |
7209c868 JM |
847 | /* |
848 | * We modify PSTATE. This won't work from irq context as the PSTATE | |
849 | * is discarded once we return from the exception. | |
850 | */ | |
851 | WARN_ON_ONCE(in_interrupt()); | |
852 | ||
338d4f49 | 853 | config_sctlr_el1(SCTLR_EL1_SPAN, 0); |
7209c868 | 854 | asm(SET_PSTATE_PAN(1)); |
2a6dcb2b | 855 | return 0; |
338d4f49 JM |
856 | } |
857 | #endif /* CONFIG_ARM64_PAN */ |