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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
21#include <linux/module.h>
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>
29#include <linux/sched.h>
30#include <linux/highmem.h>
31#include <linux/perf_event.h>
32
33#include <asm/cpufeature.h>
34#include <asm/exception.h>
35#include <asm/debug-monitors.h>
36#include <asm/esr.h>
37#include <asm/sysreg.h>
38#include <asm/system_misc.h>
39#include <asm/pgtable.h>
40#include <asm/tlbflush.h>
41
42static const char *fault_name(unsigned int esr);
43
44/*
45 * Dump out the page tables associated with 'addr' in mm 'mm'.
46 */
47void show_pte(struct mm_struct *mm, unsigned long addr)
48{
49 pgd_t *pgd;
50
51 if (!mm)
52 mm = &init_mm;
53
54 pr_alert("pgd = %p\n", mm->pgd);
55 pgd = pgd_offset(mm, addr);
56 pr_alert("[%08lx] *pgd=%016llx", addr, pgd_val(*pgd));
57
58 do {
59 pud_t *pud;
60 pmd_t *pmd;
61 pte_t *pte;
62
63 if (pgd_none(*pgd) || pgd_bad(*pgd))
64 break;
65
66 pud = pud_offset(pgd, addr);
67 printk(", *pud=%016llx", pud_val(*pud));
68 if (pud_none(*pud) || pud_bad(*pud))
69 break;
70
71 pmd = pmd_offset(pud, addr);
72 printk(", *pmd=%016llx", pmd_val(*pmd));
73 if (pmd_none(*pmd) || pmd_bad(*pmd))
74 break;
75
76 pte = pte_offset_map(pmd, addr);
77 printk(", *pte=%016llx", pte_val(*pte));
78 pte_unmap(pte);
79 } while(0);
80
81 printk("\n");
82}
83
84/*
85 * The kernel tried to access some page that wasn't present.
86 */
87static void __do_kernel_fault(struct mm_struct *mm, unsigned long addr,
88 unsigned int esr, struct pt_regs *regs)
89{
90 /*
91 * Are we prepared to handle this kernel fault?
92 */
93 if (fixup_exception(regs))
94 return;
95
96 /*
97 * No handler, we'll have to terminate things with extreme prejudice.
98 */
99 bust_spinlocks(1);
100 pr_alert("Unable to handle kernel %s at virtual address %08lx\n",
101 (addr < PAGE_SIZE) ? "NULL pointer dereference" :
102 "paging request", addr);
103
104 show_pte(mm, addr);
105 die("Oops", regs, esr);
106 bust_spinlocks(0);
107 do_exit(SIGKILL);
108}
109
110/*
111 * Something tried to access memory that isn't in our memory map. User mode
112 * accesses just cause a SIGSEGV
113 */
114static void __do_user_fault(struct task_struct *tsk, unsigned long addr,
115 unsigned int esr, unsigned int sig, int code,
116 struct pt_regs *regs)
117{
118 struct siginfo si;
119
120 if (unhandled_signal(tsk, sig) && show_unhandled_signals_ratelimited()) {
121 pr_info("%s[%d]: unhandled %s (%d) at 0x%08lx, esr 0x%03x\n",
122 tsk->comm, task_pid_nr(tsk), fault_name(esr), sig,
123 addr, esr);
124 show_pte(tsk->mm, addr);
125 show_regs(regs);
126 }
127
128 tsk->thread.fault_address = addr;
129 tsk->thread.fault_code = esr;
130 si.si_signo = sig;
131 si.si_errno = 0;
132 si.si_code = code;
133 si.si_addr = (void __user *)addr;
134 force_sig_info(sig, &si, tsk);
135}
136
137static void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *regs)
138{
139 struct task_struct *tsk = current;
140 struct mm_struct *mm = tsk->active_mm;
141
142 /*
143 * If we are in kernel mode at this point, we have no context to
144 * handle this fault with.
145 */
146 if (user_mode(regs))
147 __do_user_fault(tsk, addr, esr, SIGSEGV, SEGV_MAPERR, regs);
148 else
149 __do_kernel_fault(mm, addr, esr, regs);
150}
151
152#define VM_FAULT_BADMAP 0x010000
153#define VM_FAULT_BADACCESS 0x020000
154
155#define ESR_LNX_EXEC (1 << 24)
156
157static int __do_page_fault(struct mm_struct *mm, unsigned long addr,
158 unsigned int mm_flags, unsigned long vm_flags,
159 struct task_struct *tsk)
160{
161 struct vm_area_struct *vma;
162 int fault;
163
164 vma = find_vma(mm, addr);
165 fault = VM_FAULT_BADMAP;
166 if (unlikely(!vma))
167 goto out;
168 if (unlikely(vma->vm_start > addr))
169 goto check_stack;
170
171 /*
172 * Ok, we have a good vm_area for this memory access, so we can handle
173 * it.
174 */
175good_area:
176 /*
177 * Check that the permissions on the VMA allow for the fault which
178 * occurred. If we encountered a write or exec fault, we must have
179 * appropriate permissions, otherwise we allow any permission.
180 */
181 if (!(vma->vm_flags & vm_flags)) {
182 fault = VM_FAULT_BADACCESS;
183 goto out;
184 }
185
186 return handle_mm_fault(mm, vma, addr & PAGE_MASK, mm_flags);
187
188check_stack:
189 if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr))
190 goto good_area;
191out:
192 return fault;
193}
194
195static inline int permission_fault(unsigned int esr)
196{
197 unsigned int ec = (esr & ESR_ELx_EC_MASK) >> ESR_ELx_EC_SHIFT;
198 unsigned int fsc_type = esr & ESR_ELx_FSC_TYPE;
199
200 return (ec == ESR_ELx_EC_DABT_CUR && fsc_type == ESR_ELx_FSC_PERM);
201}
202
203static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
204 struct pt_regs *regs)
205{
206 struct task_struct *tsk;
207 struct mm_struct *mm;
208 int fault, sig, code;
209 unsigned long vm_flags = VM_READ | VM_WRITE | VM_EXEC;
210 unsigned int mm_flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
211
212 tsk = current;
213 mm = tsk->mm;
214
215 /* Enable interrupts if they were enabled in the parent context. */
216 if (interrupts_enabled(regs))
217 local_irq_enable();
218
219 /*
220 * If we're in an interrupt or have no user context, we must not take
221 * the fault.
222 */
223 if (faulthandler_disabled() || !mm)
224 goto no_context;
225
226 if (user_mode(regs))
227 mm_flags |= FAULT_FLAG_USER;
228
229 if (esr & ESR_LNX_EXEC) {
230 vm_flags = VM_EXEC;
231 } else if ((esr & ESR_ELx_WNR) && !(esr & ESR_ELx_CM)) {
232 vm_flags = VM_WRITE;
233 mm_flags |= FAULT_FLAG_WRITE;
234 }
235
236 if (permission_fault(esr) && (addr < USER_DS)) {
237 if (get_fs() == KERNEL_DS)
238 die("Accessing user space memory with fs=KERNEL_DS", regs, esr);
239
240 if (!search_exception_tables(regs->pc))
241 die("Accessing user space memory outside uaccess.h routines", regs, esr);
242 }
243
244 /*
245 * As per x86, we may deadlock here. However, since the kernel only
246 * validly references user space from well defined areas of the code,
247 * we can bug out early if this is from code which shouldn't.
248 */
249 if (!down_read_trylock(&mm->mmap_sem)) {
250 if (!user_mode(regs) && !search_exception_tables(regs->pc))
251 goto no_context;
252retry:
253 down_read(&mm->mmap_sem);
254 } else {
255 /*
256 * The above down_read_trylock() might have succeeded in which
257 * case, we'll have missed the might_sleep() from down_read().
258 */
259 might_sleep();
260#ifdef CONFIG_DEBUG_VM
261 if (!user_mode(regs) && !search_exception_tables(regs->pc))
262 goto no_context;
263#endif
264 }
265
266 fault = __do_page_fault(mm, addr, mm_flags, vm_flags, tsk);
267
268 /*
269 * If we need to retry but a fatal signal is pending, handle the
270 * signal first. We do not need to release the mmap_sem because it
271 * would already be released in __lock_page_or_retry in mm/filemap.c.
272 */
273 if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
274 return 0;
275
276 /*
277 * Major/minor page fault accounting is only done on the initial
278 * attempt. If we go through a retry, it is extremely likely that the
279 * page will be found in page cache at that point.
280 */
281
282 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);
283 if (mm_flags & FAULT_FLAG_ALLOW_RETRY) {
284 if (fault & VM_FAULT_MAJOR) {
285 tsk->maj_flt++;
286 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs,
287 addr);
288 } else {
289 tsk->min_flt++;
290 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs,
291 addr);
292 }
293 if (fault & VM_FAULT_RETRY) {
294 /*
295 * Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk of
296 * starvation.
297 */
298 mm_flags &= ~FAULT_FLAG_ALLOW_RETRY;
299 mm_flags |= FAULT_FLAG_TRIED;
300 goto retry;
301 }
302 }
303
304 up_read(&mm->mmap_sem);
305
306 /*
307 * Handle the "normal" case first - VM_FAULT_MAJOR
308 */
309 if (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP |
310 VM_FAULT_BADACCESS))))
311 return 0;
312
313 /*
314 * If we are in kernel mode at this point, we have no context to
315 * handle this fault with.
316 */
317 if (!user_mode(regs))
318 goto no_context;
319
320 if (fault & VM_FAULT_OOM) {
321 /*
322 * We ran out of memory, call the OOM killer, and return to
323 * userspace (which will retry the fault, or kill us if we got
324 * oom-killed).
325 */
326 pagefault_out_of_memory();
327 return 0;
328 }
329
330 if (fault & VM_FAULT_SIGBUS) {
331 /*
332 * We had some memory, but were unable to successfully fix up
333 * this page fault.
334 */
335 sig = SIGBUS;
336 code = BUS_ADRERR;
337 } else {
338 /*
339 * Something tried to access memory that isn't in our memory
340 * map.
341 */
342 sig = SIGSEGV;
343 code = fault == VM_FAULT_BADACCESS ?
344 SEGV_ACCERR : SEGV_MAPERR;
345 }
346
347 __do_user_fault(tsk, addr, esr, sig, code, regs);
348 return 0;
349
350no_context:
351 __do_kernel_fault(mm, addr, esr, regs);
352 return 0;
353}
354
355/*
356 * First Level Translation Fault Handler
357 *
358 * We enter here because the first level page table doesn't contain a valid
359 * entry for the address.
360 *
361 * If the address is in kernel space (>= TASK_SIZE), then we are probably
362 * faulting in the vmalloc() area.
363 *
364 * If the init_task's first level page tables contains the relevant entry, we
365 * copy the it to this task. If not, we send the process a signal, fixup the
366 * exception, or oops the kernel.
367 *
368 * NOTE! We MUST NOT take any locks for this case. We may be in an interrupt
369 * or a critical region, and should only copy the information from the master
370 * page table, nothing more.
371 */
372static int __kprobes do_translation_fault(unsigned long addr,
373 unsigned int esr,
374 struct pt_regs *regs)
375{
376 if (addr < TASK_SIZE)
377 return do_page_fault(addr, esr, regs);
378
379 do_bad_area(addr, esr, regs);
380 return 0;
381}
382
383static int do_alignment_fault(unsigned long addr, unsigned int esr,
384 struct pt_regs *regs)
385{
386 do_bad_area(addr, esr, regs);
387 return 0;
388}
389
390/*
391 * This abort handler always returns "fault".
392 */
393static int do_bad(unsigned long addr, unsigned int esr, struct pt_regs *regs)
394{
395 return 1;
396}
397
398static struct fault_info {
399 int (*fn)(unsigned long addr, unsigned int esr, struct pt_regs *regs);
400 int sig;
401 int code;
402 const char *name;
403} fault_info[] = {
404 { do_bad, SIGBUS, 0, "ttbr address size fault" },
405 { do_bad, SIGBUS, 0, "level 1 address size fault" },
406 { do_bad, SIGBUS, 0, "level 2 address size fault" },
407 { do_bad, SIGBUS, 0, "level 3 address size fault" },
408 { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 0 translation fault" },
409 { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 1 translation fault" },
410 { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 2 translation fault" },
411 { do_page_fault, SIGSEGV, SEGV_MAPERR, "level 3 translation fault" },
412 { do_bad, SIGBUS, 0, "unknown 8" },
413 { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 1 access flag fault" },
414 { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 2 access flag fault" },
415 { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 3 access flag fault" },
416 { do_bad, SIGBUS, 0, "unknown 12" },
417 { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 1 permission fault" },
418 { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 2 permission fault" },
419 { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 3 permission fault" },
420 { do_bad, SIGBUS, 0, "synchronous external abort" },
421 { do_bad, SIGBUS, 0, "unknown 17" },
422 { do_bad, SIGBUS, 0, "unknown 18" },
423 { do_bad, SIGBUS, 0, "unknown 19" },
424 { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" },
425 { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" },
426 { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" },
427 { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" },
428 { do_bad, SIGBUS, 0, "synchronous parity error" },
429 { do_bad, SIGBUS, 0, "unknown 25" },
430 { do_bad, SIGBUS, 0, "unknown 26" },
431 { do_bad, SIGBUS, 0, "unknown 27" },
432 { do_bad, SIGBUS, 0, "synchronous parity error (translation table walk)" },
433 { do_bad, SIGBUS, 0, "synchronous parity error (translation table walk)" },
434 { do_bad, SIGBUS, 0, "synchronous parity error (translation table walk)" },
435 { do_bad, SIGBUS, 0, "synchronous parity error (translation table walk)" },
436 { do_bad, SIGBUS, 0, "unknown 32" },
437 { do_alignment_fault, SIGBUS, BUS_ADRALN, "alignment fault" },
438 { do_bad, SIGBUS, 0, "unknown 34" },
439 { do_bad, SIGBUS, 0, "unknown 35" },
440 { do_bad, SIGBUS, 0, "unknown 36" },
441 { do_bad, SIGBUS, 0, "unknown 37" },
442 { do_bad, SIGBUS, 0, "unknown 38" },
443 { do_bad, SIGBUS, 0, "unknown 39" },
444 { do_bad, SIGBUS, 0, "unknown 40" },
445 { do_bad, SIGBUS, 0, "unknown 41" },
446 { do_bad, SIGBUS, 0, "unknown 42" },
447 { do_bad, SIGBUS, 0, "unknown 43" },
448 { do_bad, SIGBUS, 0, "unknown 44" },
449 { do_bad, SIGBUS, 0, "unknown 45" },
450 { do_bad, SIGBUS, 0, "unknown 46" },
451 { do_bad, SIGBUS, 0, "unknown 47" },
452 { do_bad, SIGBUS, 0, "TLB conflict abort" },
453 { do_bad, SIGBUS, 0, "unknown 49" },
454 { do_bad, SIGBUS, 0, "unknown 50" },
455 { do_bad, SIGBUS, 0, "unknown 51" },
456 { do_bad, SIGBUS, 0, "implementation fault (lockdown abort)" },
457 { do_bad, SIGBUS, 0, "implementation fault (unsupported exclusive)" },
458 { do_bad, SIGBUS, 0, "unknown 54" },
459 { do_bad, SIGBUS, 0, "unknown 55" },
460 { do_bad, SIGBUS, 0, "unknown 56" },
461 { do_bad, SIGBUS, 0, "unknown 57" },
462 { do_bad, SIGBUS, 0, "unknown 58" },
463 { do_bad, SIGBUS, 0, "unknown 59" },
464 { do_bad, SIGBUS, 0, "unknown 60" },
465 { do_bad, SIGBUS, 0, "section domain fault" },
466 { do_bad, SIGBUS, 0, "page domain fault" },
467 { do_bad, SIGBUS, 0, "unknown 63" },
468};
469
470static const char *fault_name(unsigned int esr)
471{
472 const struct fault_info *inf = fault_info + (esr & 63);
473 return inf->name;
474}
475
476/*
477 * Dispatch a data abort to the relevant handler.
478 */
479asmlinkage void __exception do_mem_abort(unsigned long addr, unsigned int esr,
480 struct pt_regs *regs)
481{
482 const struct fault_info *inf = fault_info + (esr & 63);
483 struct siginfo info;
484
485 if (!inf->fn(addr, esr, regs))
486 return;
487
488 pr_alert("Unhandled fault: %s (0x%08x) at 0x%016lx\n",
489 inf->name, esr, addr);
490
491 info.si_signo = inf->sig;
492 info.si_errno = 0;
493 info.si_code = inf->code;
494 info.si_addr = (void __user *)addr;
495 arm64_notify_die("", regs, &info, esr);
496}
497
498/*
499 * Handle stack alignment exceptions.
500 */
501asmlinkage void __exception do_sp_pc_abort(unsigned long addr,
502 unsigned int esr,
503 struct pt_regs *regs)
504{
505 struct siginfo info;
506 struct task_struct *tsk = current;
507
508 if (show_unhandled_signals && unhandled_signal(tsk, SIGBUS))
509 pr_info_ratelimited("%s[%d]: %s exception: pc=%p sp=%p\n",
510 tsk->comm, task_pid_nr(tsk),
511 esr_get_class_string(esr), (void *)regs->pc,
512 (void *)regs->sp);
513
514 info.si_signo = SIGBUS;
515 info.si_errno = 0;
516 info.si_code = BUS_ADRALN;
517 info.si_addr = (void __user *)addr;
518 arm64_notify_die("Oops - SP/PC alignment exception", regs, &info, esr);
519}
520
521int __init early_brk64(unsigned long addr, unsigned int esr,
522 struct pt_regs *regs);
523
524/*
525 * __refdata because early_brk64 is __init, but the reference to it is
526 * clobbered at arch_initcall time.
527 * See traps.c and debug-monitors.c:debug_traps_init().
528 */
529static struct fault_info __refdata debug_fault_info[] = {
530 { do_bad, SIGTRAP, TRAP_HWBKPT, "hardware breakpoint" },
531 { do_bad, SIGTRAP, TRAP_HWBKPT, "hardware single-step" },
532 { do_bad, SIGTRAP, TRAP_HWBKPT, "hardware watchpoint" },
533 { do_bad, SIGBUS, 0, "unknown 3" },
534 { do_bad, SIGTRAP, TRAP_BRKPT, "aarch32 BKPT" },
535 { do_bad, SIGTRAP, 0, "aarch32 vector catch" },
536 { early_brk64, SIGTRAP, TRAP_BRKPT, "aarch64 BRK" },
537 { do_bad, SIGBUS, 0, "unknown 7" },
538};
539
540void __init hook_debug_fault_code(int nr,
541 int (*fn)(unsigned long, unsigned int, struct pt_regs *),
542 int sig, int code, const char *name)
543{
544 BUG_ON(nr < 0 || nr >= ARRAY_SIZE(debug_fault_info));
545
546 debug_fault_info[nr].fn = fn;
547 debug_fault_info[nr].sig = sig;
548 debug_fault_info[nr].code = code;
549 debug_fault_info[nr].name = name;
550}
551
552asmlinkage int __exception do_debug_exception(unsigned long addr,
553 unsigned int esr,
554 struct pt_regs *regs)
555{
556 const struct fault_info *inf = debug_fault_info + DBG_ESR_EVT(esr);
557 struct siginfo info;
558
559 if (!inf->fn(addr, esr, regs))
560 return 1;
561
562 pr_alert("Unhandled debug exception: %s (0x%08x) at 0x%016lx\n",
563 inf->name, esr, addr);
564
565 info.si_signo = inf->sig;
566 info.si_errno = 0;
567 info.si_code = inf->code;
568 info.si_addr = (void __user *)addr;
569 arm64_notify_die("", regs, &info, 0);
570
571 return 0;
572}
573
574#ifdef CONFIG_ARM64_PAN
575void cpu_enable_pan(void *__unused)
576{
577 config_sctlr_el1(SCTLR_EL1_SPAN, 0);
578}
579#endif /* CONFIG_ARM64_PAN */
580
581#ifdef CONFIG_ARM64_UAO
582/*
583 * Kernel threads have fs=KERNEL_DS by default, and don't need to call
584 * set_fs(), devtmpfs in particular relies on this behaviour.
585 * We need to enable the feature at runtime (instead of adding it to
586 * PSR_MODE_EL1h) as the feature may not be implemented by the cpu.
587 */
588void cpu_enable_uao(void *__unused)
589{
590 asm(SET_PSTATE_UAO(1));
591}
592#endif /* CONFIG_ARM64_UAO */
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Based on arch/arm/mm/fault.c
4 *
5 * Copyright (C) 1995 Linus Torvalds
6 * Copyright (C) 1995-2004 Russell King
7 * Copyright (C) 2012 ARM Ltd.
8 */
9
10#include <linux/acpi.h>
11#include <linux/bitfield.h>
12#include <linux/extable.h>
13#include <linux/kfence.h>
14#include <linux/signal.h>
15#include <linux/mm.h>
16#include <linux/hardirq.h>
17#include <linux/init.h>
18#include <linux/kasan.h>
19#include <linux/kprobes.h>
20#include <linux/uaccess.h>
21#include <linux/page-flags.h>
22#include <linux/sched/signal.h>
23#include <linux/sched/debug.h>
24#include <linux/highmem.h>
25#include <linux/perf_event.h>
26#include <linux/preempt.h>
27#include <linux/hugetlb.h>
28
29#include <asm/acpi.h>
30#include <asm/bug.h>
31#include <asm/cmpxchg.h>
32#include <asm/cpufeature.h>
33#include <asm/exception.h>
34#include <asm/daifflags.h>
35#include <asm/debug-monitors.h>
36#include <asm/esr.h>
37#include <asm/kprobes.h>
38#include <asm/mte.h>
39#include <asm/processor.h>
40#include <asm/sysreg.h>
41#include <asm/system_misc.h>
42#include <asm/tlbflush.h>
43#include <asm/traps.h>
44
45struct fault_info {
46 int (*fn)(unsigned long far, unsigned int esr,
47 struct pt_regs *regs);
48 int sig;
49 int code;
50 const char *name;
51};
52
53static const struct fault_info fault_info[];
54static struct fault_info debug_fault_info[];
55
56static inline const struct fault_info *esr_to_fault_info(unsigned int esr)
57{
58 return fault_info + (esr & ESR_ELx_FSC);
59}
60
61static inline const struct fault_info *esr_to_debug_fault_info(unsigned int esr)
62{
63 return debug_fault_info + DBG_ESR_EVT(esr);
64}
65
66static void data_abort_decode(unsigned int esr)
67{
68 pr_alert("Data abort info:\n");
69
70 if (esr & ESR_ELx_ISV) {
71 pr_alert(" Access size = %u byte(s)\n",
72 1U << ((esr & ESR_ELx_SAS) >> ESR_ELx_SAS_SHIFT));
73 pr_alert(" SSE = %lu, SRT = %lu\n",
74 (esr & ESR_ELx_SSE) >> ESR_ELx_SSE_SHIFT,
75 (esr & ESR_ELx_SRT_MASK) >> ESR_ELx_SRT_SHIFT);
76 pr_alert(" SF = %lu, AR = %lu\n",
77 (esr & ESR_ELx_SF) >> ESR_ELx_SF_SHIFT,
78 (esr & ESR_ELx_AR) >> ESR_ELx_AR_SHIFT);
79 } else {
80 pr_alert(" ISV = 0, ISS = 0x%08lx\n", esr & ESR_ELx_ISS_MASK);
81 }
82
83 pr_alert(" CM = %lu, WnR = %lu\n",
84 (esr & ESR_ELx_CM) >> ESR_ELx_CM_SHIFT,
85 (esr & ESR_ELx_WNR) >> ESR_ELx_WNR_SHIFT);
86}
87
88static void mem_abort_decode(unsigned int esr)
89{
90 pr_alert("Mem abort info:\n");
91
92 pr_alert(" ESR = 0x%08x\n", esr);
93 pr_alert(" EC = 0x%02lx: %s, IL = %u bits\n",
94 ESR_ELx_EC(esr), esr_get_class_string(esr),
95 (esr & ESR_ELx_IL) ? 32 : 16);
96 pr_alert(" SET = %lu, FnV = %lu\n",
97 (esr & ESR_ELx_SET_MASK) >> ESR_ELx_SET_SHIFT,
98 (esr & ESR_ELx_FnV) >> ESR_ELx_FnV_SHIFT);
99 pr_alert(" EA = %lu, S1PTW = %lu\n",
100 (esr & ESR_ELx_EA) >> ESR_ELx_EA_SHIFT,
101 (esr & ESR_ELx_S1PTW) >> ESR_ELx_S1PTW_SHIFT);
102 pr_alert(" FSC = 0x%02x: %s\n", (esr & ESR_ELx_FSC),
103 esr_to_fault_info(esr)->name);
104
105 if (esr_is_data_abort(esr))
106 data_abort_decode(esr);
107}
108
109static inline unsigned long mm_to_pgd_phys(struct mm_struct *mm)
110{
111 /* Either init_pg_dir or swapper_pg_dir */
112 if (mm == &init_mm)
113 return __pa_symbol(mm->pgd);
114
115 return (unsigned long)virt_to_phys(mm->pgd);
116}
117
118/*
119 * Dump out the page tables associated with 'addr' in the currently active mm.
120 */
121static void show_pte(unsigned long addr)
122{
123 struct mm_struct *mm;
124 pgd_t *pgdp;
125 pgd_t pgd;
126
127 if (is_ttbr0_addr(addr)) {
128 /* TTBR0 */
129 mm = current->active_mm;
130 if (mm == &init_mm) {
131 pr_alert("[%016lx] user address but active_mm is swapper\n",
132 addr);
133 return;
134 }
135 } else if (is_ttbr1_addr(addr)) {
136 /* TTBR1 */
137 mm = &init_mm;
138 } else {
139 pr_alert("[%016lx] address between user and kernel address ranges\n",
140 addr);
141 return;
142 }
143
144 pr_alert("%s pgtable: %luk pages, %llu-bit VAs, pgdp=%016lx\n",
145 mm == &init_mm ? "swapper" : "user", PAGE_SIZE / SZ_1K,
146 vabits_actual, mm_to_pgd_phys(mm));
147 pgdp = pgd_offset(mm, addr);
148 pgd = READ_ONCE(*pgdp);
149 pr_alert("[%016lx] pgd=%016llx", addr, pgd_val(pgd));
150
151 do {
152 p4d_t *p4dp, p4d;
153 pud_t *pudp, pud;
154 pmd_t *pmdp, pmd;
155 pte_t *ptep, pte;
156
157 if (pgd_none(pgd) || pgd_bad(pgd))
158 break;
159
160 p4dp = p4d_offset(pgdp, addr);
161 p4d = READ_ONCE(*p4dp);
162 pr_cont(", p4d=%016llx", p4d_val(p4d));
163 if (p4d_none(p4d) || p4d_bad(p4d))
164 break;
165
166 pudp = pud_offset(p4dp, addr);
167 pud = READ_ONCE(*pudp);
168 pr_cont(", pud=%016llx", pud_val(pud));
169 if (pud_none(pud) || pud_bad(pud))
170 break;
171
172 pmdp = pmd_offset(pudp, addr);
173 pmd = READ_ONCE(*pmdp);
174 pr_cont(", pmd=%016llx", pmd_val(pmd));
175 if (pmd_none(pmd) || pmd_bad(pmd))
176 break;
177
178 ptep = pte_offset_map(pmdp, addr);
179 pte = READ_ONCE(*ptep);
180 pr_cont(", pte=%016llx", pte_val(pte));
181 pte_unmap(ptep);
182 } while(0);
183
184 pr_cont("\n");
185}
186
187/*
188 * This function sets the access flags (dirty, accessed), as well as write
189 * permission, and only to a more permissive setting.
190 *
191 * It needs to cope with hardware update of the accessed/dirty state by other
192 * agents in the system and can safely skip the __sync_icache_dcache() call as,
193 * like set_pte_at(), the PTE is never changed from no-exec to exec here.
194 *
195 * Returns whether or not the PTE actually changed.
196 */
197int ptep_set_access_flags(struct vm_area_struct *vma,
198 unsigned long address, pte_t *ptep,
199 pte_t entry, int dirty)
200{
201 pteval_t old_pteval, pteval;
202 pte_t pte = READ_ONCE(*ptep);
203
204 if (pte_same(pte, entry))
205 return 0;
206
207 /* only preserve the access flags and write permission */
208 pte_val(entry) &= PTE_RDONLY | PTE_AF | PTE_WRITE | PTE_DIRTY;
209
210 /*
211 * Setting the flags must be done atomically to avoid racing with the
212 * hardware update of the access/dirty state. The PTE_RDONLY bit must
213 * be set to the most permissive (lowest value) of *ptep and entry
214 * (calculated as: a & b == ~(~a | ~b)).
215 */
216 pte_val(entry) ^= PTE_RDONLY;
217 pteval = pte_val(pte);
218 do {
219 old_pteval = pteval;
220 pteval ^= PTE_RDONLY;
221 pteval |= pte_val(entry);
222 pteval ^= PTE_RDONLY;
223 pteval = cmpxchg_relaxed(&pte_val(*ptep), old_pteval, pteval);
224 } while (pteval != old_pteval);
225
226 /* Invalidate a stale read-only entry */
227 if (dirty)
228 flush_tlb_page(vma, address);
229 return 1;
230}
231
232static bool is_el1_instruction_abort(unsigned int esr)
233{
234 return ESR_ELx_EC(esr) == ESR_ELx_EC_IABT_CUR;
235}
236
237static bool is_el1_data_abort(unsigned int esr)
238{
239 return ESR_ELx_EC(esr) == ESR_ELx_EC_DABT_CUR;
240}
241
242static inline bool is_el1_permission_fault(unsigned long addr, unsigned int esr,
243 struct pt_regs *regs)
244{
245 unsigned int fsc_type = esr & ESR_ELx_FSC_TYPE;
246
247 if (!is_el1_data_abort(esr) && !is_el1_instruction_abort(esr))
248 return false;
249
250 if (fsc_type == ESR_ELx_FSC_PERM)
251 return true;
252
253 if (is_ttbr0_addr(addr) && system_uses_ttbr0_pan())
254 return fsc_type == ESR_ELx_FSC_FAULT &&
255 (regs->pstate & PSR_PAN_BIT);
256
257 return false;
258}
259
260static bool __kprobes is_spurious_el1_translation_fault(unsigned long addr,
261 unsigned int esr,
262 struct pt_regs *regs)
263{
264 unsigned long flags;
265 u64 par, dfsc;
266
267 if (!is_el1_data_abort(esr) ||
268 (esr & ESR_ELx_FSC_TYPE) != ESR_ELx_FSC_FAULT)
269 return false;
270
271 local_irq_save(flags);
272 asm volatile("at s1e1r, %0" :: "r" (addr));
273 isb();
274 par = read_sysreg_par();
275 local_irq_restore(flags);
276
277 /*
278 * If we now have a valid translation, treat the translation fault as
279 * spurious.
280 */
281 if (!(par & SYS_PAR_EL1_F))
282 return true;
283
284 /*
285 * If we got a different type of fault from the AT instruction,
286 * treat the translation fault as spurious.
287 */
288 dfsc = FIELD_GET(SYS_PAR_EL1_FST, par);
289 return (dfsc & ESR_ELx_FSC_TYPE) != ESR_ELx_FSC_FAULT;
290}
291
292static void die_kernel_fault(const char *msg, unsigned long addr,
293 unsigned int esr, struct pt_regs *regs)
294{
295 bust_spinlocks(1);
296
297 pr_alert("Unable to handle kernel %s at virtual address %016lx\n", msg,
298 addr);
299
300 mem_abort_decode(esr);
301
302 show_pte(addr);
303 die("Oops", regs, esr);
304 bust_spinlocks(0);
305 do_exit(SIGKILL);
306}
307
308#ifdef CONFIG_KASAN_HW_TAGS
309static void report_tag_fault(unsigned long addr, unsigned int esr,
310 struct pt_regs *regs)
311{
312 static bool reported;
313 bool is_write;
314
315 if (READ_ONCE(reported))
316 return;
317
318 /*
319 * This is used for KASAN tests and assumes that no MTE faults
320 * happened before running the tests.
321 */
322 if (mte_report_once())
323 WRITE_ONCE(reported, true);
324
325 /*
326 * SAS bits aren't set for all faults reported in EL1, so we can't
327 * find out access size.
328 */
329 is_write = !!(esr & ESR_ELx_WNR);
330 kasan_report(addr, 0, is_write, regs->pc);
331}
332#else
333/* Tag faults aren't enabled without CONFIG_KASAN_HW_TAGS. */
334static inline void report_tag_fault(unsigned long addr, unsigned int esr,
335 struct pt_regs *regs) { }
336#endif
337
338static void do_tag_recovery(unsigned long addr, unsigned int esr,
339 struct pt_regs *regs)
340{
341
342 report_tag_fault(addr, esr, regs);
343
344 /*
345 * Disable MTE Tag Checking on the local CPU for the current EL.
346 * It will be done lazily on the other CPUs when they will hit a
347 * tag fault.
348 */
349 sysreg_clear_set(sctlr_el1, SCTLR_ELx_TCF_MASK, SCTLR_ELx_TCF_NONE);
350 isb();
351}
352
353static bool is_el1_mte_sync_tag_check_fault(unsigned int esr)
354{
355 unsigned int fsc = esr & ESR_ELx_FSC;
356
357 if (!is_el1_data_abort(esr))
358 return false;
359
360 if (fsc == ESR_ELx_FSC_MTE)
361 return true;
362
363 return false;
364}
365
366static void __do_kernel_fault(unsigned long addr, unsigned int esr,
367 struct pt_regs *regs)
368{
369 const char *msg;
370
371 /*
372 * Are we prepared to handle this kernel fault?
373 * We are almost certainly not prepared to handle instruction faults.
374 */
375 if (!is_el1_instruction_abort(esr) && fixup_exception(regs))
376 return;
377
378 if (WARN_RATELIMIT(is_spurious_el1_translation_fault(addr, esr, regs),
379 "Ignoring spurious kernel translation fault at virtual address %016lx\n", addr))
380 return;
381
382 if (is_el1_mte_sync_tag_check_fault(esr)) {
383 do_tag_recovery(addr, esr, regs);
384
385 return;
386 }
387
388 if (is_el1_permission_fault(addr, esr, regs)) {
389 if (esr & ESR_ELx_WNR)
390 msg = "write to read-only memory";
391 else if (is_el1_instruction_abort(esr))
392 msg = "execute from non-executable memory";
393 else
394 msg = "read from unreadable memory";
395 } else if (addr < PAGE_SIZE) {
396 msg = "NULL pointer dereference";
397 } else {
398 if (kfence_handle_page_fault(addr, esr & ESR_ELx_WNR, regs))
399 return;
400
401 msg = "paging request";
402 }
403
404 die_kernel_fault(msg, addr, esr, regs);
405}
406
407static void set_thread_esr(unsigned long address, unsigned int esr)
408{
409 current->thread.fault_address = address;
410
411 /*
412 * If the faulting address is in the kernel, we must sanitize the ESR.
413 * From userspace's point of view, kernel-only mappings don't exist
414 * at all, so we report them as level 0 translation faults.
415 * (This is not quite the way that "no mapping there at all" behaves:
416 * an alignment fault not caused by the memory type would take
417 * precedence over translation fault for a real access to empty
418 * space. Unfortunately we can't easily distinguish "alignment fault
419 * not caused by memory type" from "alignment fault caused by memory
420 * type", so we ignore this wrinkle and just return the translation
421 * fault.)
422 */
423 if (!is_ttbr0_addr(current->thread.fault_address)) {
424 switch (ESR_ELx_EC(esr)) {
425 case ESR_ELx_EC_DABT_LOW:
426 /*
427 * These bits provide only information about the
428 * faulting instruction, which userspace knows already.
429 * We explicitly clear bits which are architecturally
430 * RES0 in case they are given meanings in future.
431 * We always report the ESR as if the fault was taken
432 * to EL1 and so ISV and the bits in ISS[23:14] are
433 * clear. (In fact it always will be a fault to EL1.)
434 */
435 esr &= ESR_ELx_EC_MASK | ESR_ELx_IL |
436 ESR_ELx_CM | ESR_ELx_WNR;
437 esr |= ESR_ELx_FSC_FAULT;
438 break;
439 case ESR_ELx_EC_IABT_LOW:
440 /*
441 * Claim a level 0 translation fault.
442 * All other bits are architecturally RES0 for faults
443 * reported with that DFSC value, so we clear them.
444 */
445 esr &= ESR_ELx_EC_MASK | ESR_ELx_IL;
446 esr |= ESR_ELx_FSC_FAULT;
447 break;
448 default:
449 /*
450 * This should never happen (entry.S only brings us
451 * into this code for insn and data aborts from a lower
452 * exception level). Fail safe by not providing an ESR
453 * context record at all.
454 */
455 WARN(1, "ESR 0x%x is not DABT or IABT from EL0\n", esr);
456 esr = 0;
457 break;
458 }
459 }
460
461 current->thread.fault_code = esr;
462}
463
464static void do_bad_area(unsigned long far, unsigned int esr,
465 struct pt_regs *regs)
466{
467 unsigned long addr = untagged_addr(far);
468
469 /*
470 * If we are in kernel mode at this point, we have no context to
471 * handle this fault with.
472 */
473 if (user_mode(regs)) {
474 const struct fault_info *inf = esr_to_fault_info(esr);
475
476 set_thread_esr(addr, esr);
477 arm64_force_sig_fault(inf->sig, inf->code, far, inf->name);
478 } else {
479 __do_kernel_fault(addr, esr, regs);
480 }
481}
482
483#define VM_FAULT_BADMAP 0x010000
484#define VM_FAULT_BADACCESS 0x020000
485
486static vm_fault_t __do_page_fault(struct mm_struct *mm, unsigned long addr,
487 unsigned int mm_flags, unsigned long vm_flags,
488 struct pt_regs *regs)
489{
490 struct vm_area_struct *vma = find_vma(mm, addr);
491
492 if (unlikely(!vma))
493 return VM_FAULT_BADMAP;
494
495 /*
496 * Ok, we have a good vm_area for this memory access, so we can handle
497 * it.
498 */
499 if (unlikely(vma->vm_start > addr)) {
500 if (!(vma->vm_flags & VM_GROWSDOWN))
501 return VM_FAULT_BADMAP;
502 if (expand_stack(vma, addr))
503 return VM_FAULT_BADMAP;
504 }
505
506 /*
507 * Check that the permissions on the VMA allow for the fault which
508 * occurred.
509 */
510 if (!(vma->vm_flags & vm_flags))
511 return VM_FAULT_BADACCESS;
512 return handle_mm_fault(vma, addr, mm_flags, regs);
513}
514
515static bool is_el0_instruction_abort(unsigned int esr)
516{
517 return ESR_ELx_EC(esr) == ESR_ELx_EC_IABT_LOW;
518}
519
520/*
521 * Note: not valid for EL1 DC IVAC, but we never use that such that it
522 * should fault. EL0 cannot issue DC IVAC (undef).
523 */
524static bool is_write_abort(unsigned int esr)
525{
526 return (esr & ESR_ELx_WNR) && !(esr & ESR_ELx_CM);
527}
528
529static int __kprobes do_page_fault(unsigned long far, unsigned int esr,
530 struct pt_regs *regs)
531{
532 const struct fault_info *inf;
533 struct mm_struct *mm = current->mm;
534 vm_fault_t fault;
535 unsigned long vm_flags;
536 unsigned int mm_flags = FAULT_FLAG_DEFAULT;
537 unsigned long addr = untagged_addr(far);
538
539 if (kprobe_page_fault(regs, esr))
540 return 0;
541
542 /*
543 * If we're in an interrupt or have no user context, we must not take
544 * the fault.
545 */
546 if (faulthandler_disabled() || !mm)
547 goto no_context;
548
549 if (user_mode(regs))
550 mm_flags |= FAULT_FLAG_USER;
551
552 /*
553 * vm_flags tells us what bits we must have in vma->vm_flags
554 * for the fault to be benign, __do_page_fault() would check
555 * vma->vm_flags & vm_flags and returns an error if the
556 * intersection is empty
557 */
558 if (is_el0_instruction_abort(esr)) {
559 /* It was exec fault */
560 vm_flags = VM_EXEC;
561 mm_flags |= FAULT_FLAG_INSTRUCTION;
562 } else if (is_write_abort(esr)) {
563 /* It was write fault */
564 vm_flags = VM_WRITE;
565 mm_flags |= FAULT_FLAG_WRITE;
566 } else {
567 /* It was read fault */
568 vm_flags = VM_READ;
569 /* Write implies read */
570 vm_flags |= VM_WRITE;
571 /* If EPAN is absent then exec implies read */
572 if (!cpus_have_const_cap(ARM64_HAS_EPAN))
573 vm_flags |= VM_EXEC;
574 }
575
576 if (is_ttbr0_addr(addr) && is_el1_permission_fault(addr, esr, regs)) {
577 if (is_el1_instruction_abort(esr))
578 die_kernel_fault("execution of user memory",
579 addr, esr, regs);
580
581 if (!search_exception_tables(regs->pc))
582 die_kernel_fault("access to user memory outside uaccess routines",
583 addr, esr, regs);
584 }
585
586 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);
587
588 /*
589 * As per x86, we may deadlock here. However, since the kernel only
590 * validly references user space from well defined areas of the code,
591 * we can bug out early if this is from code which shouldn't.
592 */
593 if (!mmap_read_trylock(mm)) {
594 if (!user_mode(regs) && !search_exception_tables(regs->pc))
595 goto no_context;
596retry:
597 mmap_read_lock(mm);
598 } else {
599 /*
600 * The above mmap_read_trylock() might have succeeded in which
601 * case, we'll have missed the might_sleep() from down_read().
602 */
603 might_sleep();
604#ifdef CONFIG_DEBUG_VM
605 if (!user_mode(regs) && !search_exception_tables(regs->pc)) {
606 mmap_read_unlock(mm);
607 goto no_context;
608 }
609#endif
610 }
611
612 fault = __do_page_fault(mm, addr, mm_flags, vm_flags, regs);
613
614 /* Quick path to respond to signals */
615 if (fault_signal_pending(fault, regs)) {
616 if (!user_mode(regs))
617 goto no_context;
618 return 0;
619 }
620
621 if (fault & VM_FAULT_RETRY) {
622 if (mm_flags & FAULT_FLAG_ALLOW_RETRY) {
623 mm_flags |= FAULT_FLAG_TRIED;
624 goto retry;
625 }
626 }
627 mmap_read_unlock(mm);
628
629 /*
630 * Handle the "normal" (no error) case first.
631 */
632 if (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP |
633 VM_FAULT_BADACCESS))))
634 return 0;
635
636 /*
637 * If we are in kernel mode at this point, we have no context to
638 * handle this fault with.
639 */
640 if (!user_mode(regs))
641 goto no_context;
642
643 if (fault & VM_FAULT_OOM) {
644 /*
645 * We ran out of memory, call the OOM killer, and return to
646 * userspace (which will retry the fault, or kill us if we got
647 * oom-killed).
648 */
649 pagefault_out_of_memory();
650 return 0;
651 }
652
653 inf = esr_to_fault_info(esr);
654 set_thread_esr(addr, esr);
655 if (fault & VM_FAULT_SIGBUS) {
656 /*
657 * We had some memory, but were unable to successfully fix up
658 * this page fault.
659 */
660 arm64_force_sig_fault(SIGBUS, BUS_ADRERR, far, inf->name);
661 } else if (fault & (VM_FAULT_HWPOISON_LARGE | VM_FAULT_HWPOISON)) {
662 unsigned int lsb;
663
664 lsb = PAGE_SHIFT;
665 if (fault & VM_FAULT_HWPOISON_LARGE)
666 lsb = hstate_index_to_shift(VM_FAULT_GET_HINDEX(fault));
667
668 arm64_force_sig_mceerr(BUS_MCEERR_AR, far, lsb, inf->name);
669 } else {
670 /*
671 * Something tried to access memory that isn't in our memory
672 * map.
673 */
674 arm64_force_sig_fault(SIGSEGV,
675 fault == VM_FAULT_BADACCESS ? SEGV_ACCERR : SEGV_MAPERR,
676 far, inf->name);
677 }
678
679 return 0;
680
681no_context:
682 __do_kernel_fault(addr, esr, regs);
683 return 0;
684}
685
686static int __kprobes do_translation_fault(unsigned long far,
687 unsigned int esr,
688 struct pt_regs *regs)
689{
690 unsigned long addr = untagged_addr(far);
691
692 if (is_ttbr0_addr(addr))
693 return do_page_fault(far, esr, regs);
694
695 do_bad_area(far, esr, regs);
696 return 0;
697}
698
699static int do_alignment_fault(unsigned long far, unsigned int esr,
700 struct pt_regs *regs)
701{
702 do_bad_area(far, esr, regs);
703 return 0;
704}
705
706static int do_bad(unsigned long far, unsigned int esr, struct pt_regs *regs)
707{
708 return 1; /* "fault" */
709}
710
711static int do_sea(unsigned long far, unsigned int esr, struct pt_regs *regs)
712{
713 const struct fault_info *inf;
714 unsigned long siaddr;
715
716 inf = esr_to_fault_info(esr);
717
718 if (user_mode(regs) && apei_claim_sea(regs) == 0) {
719 /*
720 * APEI claimed this as a firmware-first notification.
721 * Some processing deferred to task_work before ret_to_user().
722 */
723 return 0;
724 }
725
726 if (esr & ESR_ELx_FnV) {
727 siaddr = 0;
728 } else {
729 /*
730 * The architecture specifies that the tag bits of FAR_EL1 are
731 * UNKNOWN for synchronous external aborts. Mask them out now
732 * so that userspace doesn't see them.
733 */
734 siaddr = untagged_addr(far);
735 }
736 arm64_notify_die(inf->name, regs, inf->sig, inf->code, siaddr, esr);
737
738 return 0;
739}
740
741static int do_tag_check_fault(unsigned long far, unsigned int esr,
742 struct pt_regs *regs)
743{
744 /*
745 * The architecture specifies that bits 63:60 of FAR_EL1 are UNKNOWN
746 * for tag check faults. Set them to corresponding bits in the untagged
747 * address.
748 */
749 far = (__untagged_addr(far) & ~MTE_TAG_MASK) | (far & MTE_TAG_MASK);
750 do_bad_area(far, esr, regs);
751 return 0;
752}
753
754static const struct fault_info fault_info[] = {
755 { do_bad, SIGKILL, SI_KERNEL, "ttbr address size fault" },
756 { do_bad, SIGKILL, SI_KERNEL, "level 1 address size fault" },
757 { do_bad, SIGKILL, SI_KERNEL, "level 2 address size fault" },
758 { do_bad, SIGKILL, SI_KERNEL, "level 3 address size fault" },
759 { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 0 translation fault" },
760 { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 1 translation fault" },
761 { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 2 translation fault" },
762 { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 3 translation fault" },
763 { do_bad, SIGKILL, SI_KERNEL, "unknown 8" },
764 { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 1 access flag fault" },
765 { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 2 access flag fault" },
766 { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 3 access flag fault" },
767 { do_bad, SIGKILL, SI_KERNEL, "unknown 12" },
768 { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 1 permission fault" },
769 { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 2 permission fault" },
770 { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 3 permission fault" },
771 { do_sea, SIGBUS, BUS_OBJERR, "synchronous external abort" },
772 { do_tag_check_fault, SIGSEGV, SEGV_MTESERR, "synchronous tag check fault" },
773 { do_bad, SIGKILL, SI_KERNEL, "unknown 18" },
774 { do_bad, SIGKILL, SI_KERNEL, "unknown 19" },
775 { do_sea, SIGKILL, SI_KERNEL, "level 0 (translation table walk)" },
776 { do_sea, SIGKILL, SI_KERNEL, "level 1 (translation table walk)" },
777 { do_sea, SIGKILL, SI_KERNEL, "level 2 (translation table walk)" },
778 { do_sea, SIGKILL, SI_KERNEL, "level 3 (translation table walk)" },
779 { do_sea, SIGBUS, BUS_OBJERR, "synchronous parity or ECC error" }, // Reserved when RAS is implemented
780 { do_bad, SIGKILL, SI_KERNEL, "unknown 25" },
781 { do_bad, SIGKILL, SI_KERNEL, "unknown 26" },
782 { do_bad, SIGKILL, SI_KERNEL, "unknown 27" },
783 { do_sea, SIGKILL, SI_KERNEL, "level 0 synchronous parity error (translation table walk)" }, // Reserved when RAS is implemented
784 { do_sea, SIGKILL, SI_KERNEL, "level 1 synchronous parity error (translation table walk)" }, // Reserved when RAS is implemented
785 { do_sea, SIGKILL, SI_KERNEL, "level 2 synchronous parity error (translation table walk)" }, // Reserved when RAS is implemented
786 { do_sea, SIGKILL, SI_KERNEL, "level 3 synchronous parity error (translation table walk)" }, // Reserved when RAS is implemented
787 { do_bad, SIGKILL, SI_KERNEL, "unknown 32" },
788 { do_alignment_fault, SIGBUS, BUS_ADRALN, "alignment fault" },
789 { do_bad, SIGKILL, SI_KERNEL, "unknown 34" },
790 { do_bad, SIGKILL, SI_KERNEL, "unknown 35" },
791 { do_bad, SIGKILL, SI_KERNEL, "unknown 36" },
792 { do_bad, SIGKILL, SI_KERNEL, "unknown 37" },
793 { do_bad, SIGKILL, SI_KERNEL, "unknown 38" },
794 { do_bad, SIGKILL, SI_KERNEL, "unknown 39" },
795 { do_bad, SIGKILL, SI_KERNEL, "unknown 40" },
796 { do_bad, SIGKILL, SI_KERNEL, "unknown 41" },
797 { do_bad, SIGKILL, SI_KERNEL, "unknown 42" },
798 { do_bad, SIGKILL, SI_KERNEL, "unknown 43" },
799 { do_bad, SIGKILL, SI_KERNEL, "unknown 44" },
800 { do_bad, SIGKILL, SI_KERNEL, "unknown 45" },
801 { do_bad, SIGKILL, SI_KERNEL, "unknown 46" },
802 { do_bad, SIGKILL, SI_KERNEL, "unknown 47" },
803 { do_bad, SIGKILL, SI_KERNEL, "TLB conflict abort" },
804 { do_bad, SIGKILL, SI_KERNEL, "Unsupported atomic hardware update fault" },
805 { do_bad, SIGKILL, SI_KERNEL, "unknown 50" },
806 { do_bad, SIGKILL, SI_KERNEL, "unknown 51" },
807 { do_bad, SIGKILL, SI_KERNEL, "implementation fault (lockdown abort)" },
808 { do_bad, SIGBUS, BUS_OBJERR, "implementation fault (unsupported exclusive)" },
809 { do_bad, SIGKILL, SI_KERNEL, "unknown 54" },
810 { do_bad, SIGKILL, SI_KERNEL, "unknown 55" },
811 { do_bad, SIGKILL, SI_KERNEL, "unknown 56" },
812 { do_bad, SIGKILL, SI_KERNEL, "unknown 57" },
813 { do_bad, SIGKILL, SI_KERNEL, "unknown 58" },
814 { do_bad, SIGKILL, SI_KERNEL, "unknown 59" },
815 { do_bad, SIGKILL, SI_KERNEL, "unknown 60" },
816 { do_bad, SIGKILL, SI_KERNEL, "section domain fault" },
817 { do_bad, SIGKILL, SI_KERNEL, "page domain fault" },
818 { do_bad, SIGKILL, SI_KERNEL, "unknown 63" },
819};
820
821void do_mem_abort(unsigned long far, unsigned int esr, struct pt_regs *regs)
822{
823 const struct fault_info *inf = esr_to_fault_info(esr);
824 unsigned long addr = untagged_addr(far);
825
826 if (!inf->fn(far, esr, regs))
827 return;
828
829 if (!user_mode(regs)) {
830 pr_alert("Unhandled fault at 0x%016lx\n", addr);
831 mem_abort_decode(esr);
832 show_pte(addr);
833 }
834
835 /*
836 * At this point we have an unrecognized fault type whose tag bits may
837 * have been defined as UNKNOWN. Therefore we only expose the untagged
838 * address to the signal handler.
839 */
840 arm64_notify_die(inf->name, regs, inf->sig, inf->code, addr, esr);
841}
842NOKPROBE_SYMBOL(do_mem_abort);
843
844void do_sp_pc_abort(unsigned long addr, unsigned int esr, struct pt_regs *regs)
845{
846 arm64_notify_die("SP/PC alignment exception", regs, SIGBUS, BUS_ADRALN,
847 addr, esr);
848}
849NOKPROBE_SYMBOL(do_sp_pc_abort);
850
851int __init early_brk64(unsigned long addr, unsigned int esr,
852 struct pt_regs *regs);
853
854/*
855 * __refdata because early_brk64 is __init, but the reference to it is
856 * clobbered at arch_initcall time.
857 * See traps.c and debug-monitors.c:debug_traps_init().
858 */
859static struct fault_info __refdata debug_fault_info[] = {
860 { do_bad, SIGTRAP, TRAP_HWBKPT, "hardware breakpoint" },
861 { do_bad, SIGTRAP, TRAP_HWBKPT, "hardware single-step" },
862 { do_bad, SIGTRAP, TRAP_HWBKPT, "hardware watchpoint" },
863 { do_bad, SIGKILL, SI_KERNEL, "unknown 3" },
864 { do_bad, SIGTRAP, TRAP_BRKPT, "aarch32 BKPT" },
865 { do_bad, SIGKILL, SI_KERNEL, "aarch32 vector catch" },
866 { early_brk64, SIGTRAP, TRAP_BRKPT, "aarch64 BRK" },
867 { do_bad, SIGKILL, SI_KERNEL, "unknown 7" },
868};
869
870void __init hook_debug_fault_code(int nr,
871 int (*fn)(unsigned long, unsigned int, struct pt_regs *),
872 int sig, int code, const char *name)
873{
874 BUG_ON(nr < 0 || nr >= ARRAY_SIZE(debug_fault_info));
875
876 debug_fault_info[nr].fn = fn;
877 debug_fault_info[nr].sig = sig;
878 debug_fault_info[nr].code = code;
879 debug_fault_info[nr].name = name;
880}
881
882/*
883 * In debug exception context, we explicitly disable preemption despite
884 * having interrupts disabled.
885 * This serves two purposes: it makes it much less likely that we would
886 * accidentally schedule in exception context and it will force a warning
887 * if we somehow manage to schedule by accident.
888 */
889static void debug_exception_enter(struct pt_regs *regs)
890{
891 preempt_disable();
892
893 /* This code is a bit fragile. Test it. */
894 RCU_LOCKDEP_WARN(!rcu_is_watching(), "exception_enter didn't work");
895}
896NOKPROBE_SYMBOL(debug_exception_enter);
897
898static void debug_exception_exit(struct pt_regs *regs)
899{
900 preempt_enable_no_resched();
901}
902NOKPROBE_SYMBOL(debug_exception_exit);
903
904void do_debug_exception(unsigned long addr_if_watchpoint, unsigned int esr,
905 struct pt_regs *regs)
906{
907 const struct fault_info *inf = esr_to_debug_fault_info(esr);
908 unsigned long pc = instruction_pointer(regs);
909
910 debug_exception_enter(regs);
911
912 if (user_mode(regs) && !is_ttbr0_addr(pc))
913 arm64_apply_bp_hardening();
914
915 if (inf->fn(addr_if_watchpoint, esr, regs)) {
916 arm64_notify_die(inf->name, regs, inf->sig, inf->code, pc, esr);
917 }
918
919 debug_exception_exit(regs);
920}
921NOKPROBE_SYMBOL(do_debug_exception);
922
923/*
924 * Used during anonymous page fault handling.
925 */
926struct page *alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma,
927 unsigned long vaddr)
928{
929 gfp_t flags = GFP_HIGHUSER_MOVABLE | __GFP_ZERO;
930
931 /*
932 * If the page is mapped with PROT_MTE, initialise the tags at the
933 * point of allocation and page zeroing as this is usually faster than
934 * separate DC ZVA and STGM.
935 */
936 if (vma->vm_flags & VM_MTE)
937 flags |= __GFP_ZEROTAGS;
938
939 return alloc_page_vma(flags, vma, vaddr);
940}
941
942void tag_clear_highpage(struct page *page)
943{
944 mte_zero_clear_page_tags(page_address(page));
945 page_kasan_tag_reset(page);
946 set_bit(PG_mte_tagged, &page->flags);
947}