| 1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | /* |
| 3 | * S390 version |
| 4 | * Copyright IBM Corp. 1999 |
| 5 | * Author(s): Hartmut Penner (hp@de.ibm.com) |
| 6 | * Ulrich Weigand (uweigand@de.ibm.com) |
| 7 | * |
| 8 | * Derived from "arch/i386/mm/fault.c" |
| 9 | * Copyright (C) 1995 Linus Torvalds |
| 10 | */ |
| 11 | |
| 12 | #include <linux/kernel_stat.h> |
| 13 | #include <linux/mmu_context.h> |
| 14 | #include <linux/perf_event.h> |
| 15 | #include <linux/signal.h> |
| 16 | #include <linux/sched.h> |
| 17 | #include <linux/sched/debug.h> |
| 18 | #include <linux/jump_label.h> |
| 19 | #include <linux/kernel.h> |
| 20 | #include <linux/errno.h> |
| 21 | #include <linux/string.h> |
| 22 | #include <linux/types.h> |
| 23 | #include <linux/ptrace.h> |
| 24 | #include <linux/mman.h> |
| 25 | #include <linux/mm.h> |
| 26 | #include <linux/compat.h> |
| 27 | #include <linux/smp.h> |
| 28 | #include <linux/kdebug.h> |
| 29 | #include <linux/init.h> |
| 30 | #include <linux/console.h> |
| 31 | #include <linux/extable.h> |
| 32 | #include <linux/hardirq.h> |
| 33 | #include <linux/kprobes.h> |
| 34 | #include <linux/uaccess.h> |
| 35 | #include <linux/hugetlb.h> |
| 36 | #include <linux/kfence.h> |
| 37 | #include <linux/pagewalk.h> |
| 38 | #include <asm/asm-extable.h> |
| 39 | #include <asm/asm-offsets.h> |
| 40 | #include <asm/ptrace.h> |
| 41 | #include <asm/fault.h> |
| 42 | #include <asm/diag.h> |
| 43 | #include <asm/gmap.h> |
| 44 | #include <asm/irq.h> |
| 45 | #include <asm/facility.h> |
| 46 | #include <asm/uv.h> |
| 47 | #include "../kernel/entry.h" |
| 48 | |
| 49 | enum fault_type { |
| 50 | KERNEL_FAULT, |
| 51 | USER_FAULT, |
| 52 | GMAP_FAULT, |
| 53 | }; |
| 54 | |
| 55 | static DEFINE_STATIC_KEY_FALSE(have_store_indication); |
| 56 | |
| 57 | static int __init fault_init(void) |
| 58 | { |
| 59 | if (test_facility(75)) |
| 60 | static_branch_enable(&have_store_indication); |
| 61 | return 0; |
| 62 | } |
| 63 | early_initcall(fault_init); |
| 64 | |
| 65 | /* |
| 66 | * Find out which address space caused the exception. |
| 67 | */ |
| 68 | static enum fault_type get_fault_type(struct pt_regs *regs) |
| 69 | { |
| 70 | union teid teid = { .val = regs->int_parm_long }; |
| 71 | struct gmap *gmap; |
| 72 | |
| 73 | if (likely(teid.as == PSW_BITS_AS_PRIMARY)) { |
| 74 | if (user_mode(regs)) |
| 75 | return USER_FAULT; |
| 76 | if (!IS_ENABLED(CONFIG_PGSTE)) |
| 77 | return KERNEL_FAULT; |
| 78 | gmap = (struct gmap *)get_lowcore()->gmap; |
| 79 | if (gmap && gmap->asce == regs->cr1) |
| 80 | return GMAP_FAULT; |
| 81 | return KERNEL_FAULT; |
| 82 | } |
| 83 | if (teid.as == PSW_BITS_AS_SECONDARY) |
| 84 | return USER_FAULT; |
| 85 | /* Access register mode, not used in the kernel */ |
| 86 | if (teid.as == PSW_BITS_AS_ACCREG) |
| 87 | return USER_FAULT; |
| 88 | /* Home space -> access via kernel ASCE */ |
| 89 | return KERNEL_FAULT; |
| 90 | } |
| 91 | |
| 92 | static unsigned long get_fault_address(struct pt_regs *regs) |
| 93 | { |
| 94 | union teid teid = { .val = regs->int_parm_long }; |
| 95 | |
| 96 | return teid.addr * PAGE_SIZE; |
| 97 | } |
| 98 | |
| 99 | static __always_inline bool fault_is_write(struct pt_regs *regs) |
| 100 | { |
| 101 | union teid teid = { .val = regs->int_parm_long }; |
| 102 | |
| 103 | if (static_branch_likely(&have_store_indication)) |
| 104 | return teid.fsi == TEID_FSI_STORE; |
| 105 | return false; |
| 106 | } |
| 107 | |
| 108 | static void dump_pagetable(unsigned long asce, unsigned long address) |
| 109 | { |
| 110 | unsigned long entry, *table = __va(asce & _ASCE_ORIGIN); |
| 111 | |
| 112 | pr_alert("AS:%016lx ", asce); |
| 113 | switch (asce & _ASCE_TYPE_MASK) { |
| 114 | case _ASCE_TYPE_REGION1: |
| 115 | table += (address & _REGION1_INDEX) >> _REGION1_SHIFT; |
| 116 | if (get_kernel_nofault(entry, table)) |
| 117 | goto bad; |
| 118 | pr_cont("R1:%016lx ", entry); |
| 119 | if (entry & _REGION_ENTRY_INVALID) |
| 120 | goto out; |
| 121 | table = __va(entry & _REGION_ENTRY_ORIGIN); |
| 122 | fallthrough; |
| 123 | case _ASCE_TYPE_REGION2: |
| 124 | table += (address & _REGION2_INDEX) >> _REGION2_SHIFT; |
| 125 | if (get_kernel_nofault(entry, table)) |
| 126 | goto bad; |
| 127 | pr_cont("R2:%016lx ", entry); |
| 128 | if (entry & _REGION_ENTRY_INVALID) |
| 129 | goto out; |
| 130 | table = __va(entry & _REGION_ENTRY_ORIGIN); |
| 131 | fallthrough; |
| 132 | case _ASCE_TYPE_REGION3: |
| 133 | table += (address & _REGION3_INDEX) >> _REGION3_SHIFT; |
| 134 | if (get_kernel_nofault(entry, table)) |
| 135 | goto bad; |
| 136 | pr_cont("R3:%016lx ", entry); |
| 137 | if (entry & (_REGION_ENTRY_INVALID | _REGION3_ENTRY_LARGE)) |
| 138 | goto out; |
| 139 | table = __va(entry & _REGION_ENTRY_ORIGIN); |
| 140 | fallthrough; |
| 141 | case _ASCE_TYPE_SEGMENT: |
| 142 | table += (address & _SEGMENT_INDEX) >> _SEGMENT_SHIFT; |
| 143 | if (get_kernel_nofault(entry, table)) |
| 144 | goto bad; |
| 145 | pr_cont("S:%016lx ", entry); |
| 146 | if (entry & (_SEGMENT_ENTRY_INVALID | _SEGMENT_ENTRY_LARGE)) |
| 147 | goto out; |
| 148 | table = __va(entry & _SEGMENT_ENTRY_ORIGIN); |
| 149 | } |
| 150 | table += (address & _PAGE_INDEX) >> _PAGE_SHIFT; |
| 151 | if (get_kernel_nofault(entry, table)) |
| 152 | goto bad; |
| 153 | pr_cont("P:%016lx ", entry); |
| 154 | out: |
| 155 | pr_cont("\n"); |
| 156 | return; |
| 157 | bad: |
| 158 | pr_cont("BAD\n"); |
| 159 | } |
| 160 | |
| 161 | static void dump_fault_info(struct pt_regs *regs) |
| 162 | { |
| 163 | union teid teid = { .val = regs->int_parm_long }; |
| 164 | unsigned long asce; |
| 165 | |
| 166 | pr_alert("Failing address: %016lx TEID: %016lx\n", |
| 167 | get_fault_address(regs), teid.val); |
| 168 | pr_alert("Fault in "); |
| 169 | switch (teid.as) { |
| 170 | case PSW_BITS_AS_HOME: |
| 171 | pr_cont("home space "); |
| 172 | break; |
| 173 | case PSW_BITS_AS_SECONDARY: |
| 174 | pr_cont("secondary space "); |
| 175 | break; |
| 176 | case PSW_BITS_AS_ACCREG: |
| 177 | pr_cont("access register "); |
| 178 | break; |
| 179 | case PSW_BITS_AS_PRIMARY: |
| 180 | pr_cont("primary space "); |
| 181 | break; |
| 182 | } |
| 183 | pr_cont("mode while using "); |
| 184 | switch (get_fault_type(regs)) { |
| 185 | case USER_FAULT: |
| 186 | asce = get_lowcore()->user_asce.val; |
| 187 | pr_cont("user "); |
| 188 | break; |
| 189 | case GMAP_FAULT: |
| 190 | asce = ((struct gmap *)get_lowcore()->gmap)->asce; |
| 191 | pr_cont("gmap "); |
| 192 | break; |
| 193 | case KERNEL_FAULT: |
| 194 | asce = get_lowcore()->kernel_asce.val; |
| 195 | pr_cont("kernel "); |
| 196 | break; |
| 197 | default: |
| 198 | unreachable(); |
| 199 | } |
| 200 | pr_cont("ASCE.\n"); |
| 201 | dump_pagetable(asce, get_fault_address(regs)); |
| 202 | } |
| 203 | |
| 204 | int show_unhandled_signals = 1; |
| 205 | |
| 206 | void report_user_fault(struct pt_regs *regs, long signr, int is_mm_fault) |
| 207 | { |
| 208 | static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL, DEFAULT_RATELIMIT_BURST); |
| 209 | |
| 210 | if ((task_pid_nr(current) > 1) && !show_unhandled_signals) |
| 211 | return; |
| 212 | if (!unhandled_signal(current, signr)) |
| 213 | return; |
| 214 | if (!__ratelimit(&rs)) |
| 215 | return; |
| 216 | pr_alert("User process fault: interruption code %04x ilc:%d ", |
| 217 | regs->int_code & 0xffff, regs->int_code >> 17); |
| 218 | print_vma_addr(KERN_CONT "in ", regs->psw.addr); |
| 219 | pr_cont("\n"); |
| 220 | if (is_mm_fault) |
| 221 | dump_fault_info(regs); |
| 222 | show_regs(regs); |
| 223 | } |
| 224 | |
| 225 | static void do_sigsegv(struct pt_regs *regs, int si_code) |
| 226 | { |
| 227 | report_user_fault(regs, SIGSEGV, 1); |
| 228 | force_sig_fault(SIGSEGV, si_code, (void __user *)get_fault_address(regs)); |
| 229 | } |
| 230 | |
| 231 | static void handle_fault_error_nolock(struct pt_regs *regs, int si_code) |
| 232 | { |
| 233 | enum fault_type fault_type; |
| 234 | unsigned long address; |
| 235 | bool is_write; |
| 236 | |
| 237 | if (user_mode(regs)) { |
| 238 | if (WARN_ON_ONCE(!si_code)) |
| 239 | si_code = SEGV_MAPERR; |
| 240 | return do_sigsegv(regs, si_code); |
| 241 | } |
| 242 | if (fixup_exception(regs)) |
| 243 | return; |
| 244 | fault_type = get_fault_type(regs); |
| 245 | if (fault_type == KERNEL_FAULT) { |
| 246 | address = get_fault_address(regs); |
| 247 | is_write = fault_is_write(regs); |
| 248 | if (kfence_handle_page_fault(address, is_write, regs)) |
| 249 | return; |
| 250 | } |
| 251 | if (fault_type == KERNEL_FAULT) |
| 252 | pr_alert("Unable to handle kernel pointer dereference in virtual kernel address space\n"); |
| 253 | else |
| 254 | pr_alert("Unable to handle kernel paging request in virtual user address space\n"); |
| 255 | dump_fault_info(regs); |
| 256 | die(regs, "Oops"); |
| 257 | } |
| 258 | |
| 259 | static void handle_fault_error(struct pt_regs *regs, int si_code) |
| 260 | { |
| 261 | struct mm_struct *mm = current->mm; |
| 262 | |
| 263 | mmap_read_unlock(mm); |
| 264 | handle_fault_error_nolock(regs, si_code); |
| 265 | } |
| 266 | |
| 267 | static void do_sigbus(struct pt_regs *regs) |
| 268 | { |
| 269 | force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)get_fault_address(regs)); |
| 270 | } |
| 271 | |
| 272 | /* |
| 273 | * This routine handles page faults. It determines the address, |
| 274 | * and the problem, and then passes it off to one of the appropriate |
| 275 | * routines. |
| 276 | * |
| 277 | * interruption code (int_code): |
| 278 | * 04 Protection -> Write-Protection (suppression) |
| 279 | * 10 Segment translation -> Not present (nullification) |
| 280 | * 11 Page translation -> Not present (nullification) |
| 281 | * 3b Region third trans. -> Not present (nullification) |
| 282 | */ |
| 283 | static void do_exception(struct pt_regs *regs, int access) |
| 284 | { |
| 285 | struct vm_area_struct *vma; |
| 286 | unsigned long address; |
| 287 | struct mm_struct *mm; |
| 288 | enum fault_type type; |
| 289 | unsigned int flags; |
| 290 | struct gmap *gmap; |
| 291 | vm_fault_t fault; |
| 292 | bool is_write; |
| 293 | |
| 294 | /* |
| 295 | * The instruction that caused the program check has |
| 296 | * been nullified. Don't signal single step via SIGTRAP. |
| 297 | */ |
| 298 | clear_thread_flag(TIF_PER_TRAP); |
| 299 | if (kprobe_page_fault(regs, 14)) |
| 300 | return; |
| 301 | mm = current->mm; |
| 302 | address = get_fault_address(regs); |
| 303 | is_write = fault_is_write(regs); |
| 304 | type = get_fault_type(regs); |
| 305 | switch (type) { |
| 306 | case KERNEL_FAULT: |
| 307 | return handle_fault_error_nolock(regs, 0); |
| 308 | case USER_FAULT: |
| 309 | case GMAP_FAULT: |
| 310 | if (faulthandler_disabled() || !mm) |
| 311 | return handle_fault_error_nolock(regs, 0); |
| 312 | break; |
| 313 | } |
| 314 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); |
| 315 | flags = FAULT_FLAG_DEFAULT; |
| 316 | if (user_mode(regs)) |
| 317 | flags |= FAULT_FLAG_USER; |
| 318 | if (is_write) |
| 319 | access = VM_WRITE; |
| 320 | if (access == VM_WRITE) |
| 321 | flags |= FAULT_FLAG_WRITE; |
| 322 | if (!(flags & FAULT_FLAG_USER)) |
| 323 | goto lock_mmap; |
| 324 | vma = lock_vma_under_rcu(mm, address); |
| 325 | if (!vma) |
| 326 | goto lock_mmap; |
| 327 | if (!(vma->vm_flags & access)) { |
| 328 | vma_end_read(vma); |
| 329 | count_vm_vma_lock_event(VMA_LOCK_SUCCESS); |
| 330 | return handle_fault_error_nolock(regs, SEGV_ACCERR); |
| 331 | } |
| 332 | fault = handle_mm_fault(vma, address, flags | FAULT_FLAG_VMA_LOCK, regs); |
| 333 | if (!(fault & (VM_FAULT_RETRY | VM_FAULT_COMPLETED))) |
| 334 | vma_end_read(vma); |
| 335 | if (!(fault & VM_FAULT_RETRY)) { |
| 336 | count_vm_vma_lock_event(VMA_LOCK_SUCCESS); |
| 337 | if (unlikely(fault & VM_FAULT_ERROR)) |
| 338 | goto error; |
| 339 | return; |
| 340 | } |
| 341 | count_vm_vma_lock_event(VMA_LOCK_RETRY); |
| 342 | if (fault & VM_FAULT_MAJOR) |
| 343 | flags |= FAULT_FLAG_TRIED; |
| 344 | |
| 345 | /* Quick path to respond to signals */ |
| 346 | if (fault_signal_pending(fault, regs)) { |
| 347 | if (!user_mode(regs)) |
| 348 | handle_fault_error_nolock(regs, 0); |
| 349 | return; |
| 350 | } |
| 351 | lock_mmap: |
| 352 | mmap_read_lock(mm); |
| 353 | gmap = NULL; |
| 354 | if (IS_ENABLED(CONFIG_PGSTE) && type == GMAP_FAULT) { |
| 355 | gmap = (struct gmap *)get_lowcore()->gmap; |
| 356 | current->thread.gmap_addr = address; |
| 357 | current->thread.gmap_write_flag = !!(flags & FAULT_FLAG_WRITE); |
| 358 | current->thread.gmap_int_code = regs->int_code & 0xffff; |
| 359 | address = __gmap_translate(gmap, address); |
| 360 | if (address == -EFAULT) |
| 361 | return handle_fault_error(regs, SEGV_MAPERR); |
| 362 | if (gmap->pfault_enabled) |
| 363 | flags |= FAULT_FLAG_RETRY_NOWAIT; |
| 364 | } |
| 365 | retry: |
| 366 | vma = find_vma(mm, address); |
| 367 | if (!vma) |
| 368 | return handle_fault_error(regs, SEGV_MAPERR); |
| 369 | if (unlikely(vma->vm_start > address)) { |
| 370 | if (!(vma->vm_flags & VM_GROWSDOWN)) |
| 371 | return handle_fault_error(regs, SEGV_MAPERR); |
| 372 | vma = expand_stack(mm, address); |
| 373 | if (!vma) |
| 374 | return handle_fault_error_nolock(regs, SEGV_MAPERR); |
| 375 | } |
| 376 | if (unlikely(!(vma->vm_flags & access))) |
| 377 | return handle_fault_error(regs, SEGV_ACCERR); |
| 378 | fault = handle_mm_fault(vma, address, flags, regs); |
| 379 | if (fault_signal_pending(fault, regs)) { |
| 380 | if (flags & FAULT_FLAG_RETRY_NOWAIT) |
| 381 | mmap_read_unlock(mm); |
| 382 | if (!user_mode(regs)) |
| 383 | handle_fault_error_nolock(regs, 0); |
| 384 | return; |
| 385 | } |
| 386 | /* The fault is fully completed (including releasing mmap lock) */ |
| 387 | if (fault & VM_FAULT_COMPLETED) { |
| 388 | if (gmap) { |
| 389 | mmap_read_lock(mm); |
| 390 | goto gmap; |
| 391 | } |
| 392 | return; |
| 393 | } |
| 394 | if (unlikely(fault & VM_FAULT_ERROR)) { |
| 395 | mmap_read_unlock(mm); |
| 396 | goto error; |
| 397 | } |
| 398 | if (fault & VM_FAULT_RETRY) { |
| 399 | if (IS_ENABLED(CONFIG_PGSTE) && gmap && (flags & FAULT_FLAG_RETRY_NOWAIT)) { |
| 400 | /* |
| 401 | * FAULT_FLAG_RETRY_NOWAIT has been set, |
| 402 | * mmap_lock has not been released |
| 403 | */ |
| 404 | current->thread.gmap_pfault = 1; |
| 405 | return handle_fault_error(regs, 0); |
| 406 | } |
| 407 | flags &= ~FAULT_FLAG_RETRY_NOWAIT; |
| 408 | flags |= FAULT_FLAG_TRIED; |
| 409 | mmap_read_lock(mm); |
| 410 | goto retry; |
| 411 | } |
| 412 | gmap: |
| 413 | if (IS_ENABLED(CONFIG_PGSTE) && gmap) { |
| 414 | address = __gmap_link(gmap, current->thread.gmap_addr, |
| 415 | address); |
| 416 | if (address == -EFAULT) |
| 417 | return handle_fault_error(regs, SEGV_MAPERR); |
| 418 | if (address == -ENOMEM) { |
| 419 | fault = VM_FAULT_OOM; |
| 420 | mmap_read_unlock(mm); |
| 421 | goto error; |
| 422 | } |
| 423 | } |
| 424 | mmap_read_unlock(mm); |
| 425 | return; |
| 426 | error: |
| 427 | if (fault & VM_FAULT_OOM) { |
| 428 | if (!user_mode(regs)) |
| 429 | handle_fault_error_nolock(regs, 0); |
| 430 | else |
| 431 | pagefault_out_of_memory(); |
| 432 | } else if (fault & VM_FAULT_SIGSEGV) { |
| 433 | if (!user_mode(regs)) |
| 434 | handle_fault_error_nolock(regs, 0); |
| 435 | else |
| 436 | do_sigsegv(regs, SEGV_MAPERR); |
| 437 | } else if (fault & (VM_FAULT_SIGBUS | VM_FAULT_HWPOISON)) { |
| 438 | if (!user_mode(regs)) |
| 439 | handle_fault_error_nolock(regs, 0); |
| 440 | else |
| 441 | do_sigbus(regs); |
| 442 | } else { |
| 443 | pr_emerg("Unexpected fault flags: %08x\n", fault); |
| 444 | BUG(); |
| 445 | } |
| 446 | } |
| 447 | |
| 448 | void do_protection_exception(struct pt_regs *regs) |
| 449 | { |
| 450 | union teid teid = { .val = regs->int_parm_long }; |
| 451 | |
| 452 | /* |
| 453 | * Protection exceptions are suppressing, decrement psw address. |
| 454 | * The exception to this rule are aborted transactions, for these |
| 455 | * the PSW already points to the correct location. |
| 456 | */ |
| 457 | if (!(regs->int_code & 0x200)) |
| 458 | regs->psw.addr = __rewind_psw(regs->psw, regs->int_code >> 16); |
| 459 | /* |
| 460 | * Check for low-address protection. This needs to be treated |
| 461 | * as a special case because the translation exception code |
| 462 | * field is not guaranteed to contain valid data in this case. |
| 463 | */ |
| 464 | if (unlikely(!teid.b61)) { |
| 465 | if (user_mode(regs)) { |
| 466 | /* Low-address protection in user mode: cannot happen */ |
| 467 | die(regs, "Low-address protection"); |
| 468 | } |
| 469 | /* |
| 470 | * Low-address protection in kernel mode means |
| 471 | * NULL pointer write access in kernel mode. |
| 472 | */ |
| 473 | return handle_fault_error_nolock(regs, 0); |
| 474 | } |
| 475 | if (unlikely(MACHINE_HAS_NX && teid.b56)) { |
| 476 | regs->int_parm_long = (teid.addr * PAGE_SIZE) | (regs->psw.addr & PAGE_MASK); |
| 477 | return handle_fault_error_nolock(regs, SEGV_ACCERR); |
| 478 | } |
| 479 | do_exception(regs, VM_WRITE); |
| 480 | } |
| 481 | NOKPROBE_SYMBOL(do_protection_exception); |
| 482 | |
| 483 | void do_dat_exception(struct pt_regs *regs) |
| 484 | { |
| 485 | do_exception(regs, VM_ACCESS_FLAGS); |
| 486 | } |
| 487 | NOKPROBE_SYMBOL(do_dat_exception); |
| 488 | |
| 489 | #if IS_ENABLED(CONFIG_PGSTE) |
| 490 | |
| 491 | void do_secure_storage_access(struct pt_regs *regs) |
| 492 | { |
| 493 | union teid teid = { .val = regs->int_parm_long }; |
| 494 | unsigned long addr = get_fault_address(regs); |
| 495 | struct vm_area_struct *vma; |
| 496 | struct folio_walk fw; |
| 497 | struct mm_struct *mm; |
| 498 | struct folio *folio; |
| 499 | struct gmap *gmap; |
| 500 | int rc; |
| 501 | |
| 502 | /* |
| 503 | * Bit 61 indicates if the address is valid, if it is not the |
| 504 | * kernel should be stopped or SIGSEGV should be sent to the |
| 505 | * process. Bit 61 is not reliable without the misc UV feature, |
| 506 | * therefore this needs to be checked too. |
| 507 | */ |
| 508 | if (uv_has_feature(BIT_UV_FEAT_MISC) && !teid.b61) { |
| 509 | /* |
| 510 | * When this happens, userspace did something that it |
| 511 | * was not supposed to do, e.g. branching into secure |
| 512 | * memory. Trigger a segmentation fault. |
| 513 | */ |
| 514 | if (user_mode(regs)) { |
| 515 | send_sig(SIGSEGV, current, 0); |
| 516 | return; |
| 517 | } |
| 518 | /* |
| 519 | * The kernel should never run into this case and |
| 520 | * there is no way out of this situation. |
| 521 | */ |
| 522 | panic("Unexpected PGM 0x3d with TEID bit 61=0"); |
| 523 | } |
| 524 | switch (get_fault_type(regs)) { |
| 525 | case GMAP_FAULT: |
| 526 | mm = current->mm; |
| 527 | gmap = (struct gmap *)get_lowcore()->gmap; |
| 528 | mmap_read_lock(mm); |
| 529 | addr = __gmap_translate(gmap, addr); |
| 530 | mmap_read_unlock(mm); |
| 531 | if (IS_ERR_VALUE(addr)) |
| 532 | return handle_fault_error_nolock(regs, SEGV_MAPERR); |
| 533 | fallthrough; |
| 534 | case USER_FAULT: |
| 535 | mm = current->mm; |
| 536 | mmap_read_lock(mm); |
| 537 | vma = find_vma(mm, addr); |
| 538 | if (!vma) |
| 539 | return handle_fault_error(regs, SEGV_MAPERR); |
| 540 | folio = folio_walk_start(&fw, vma, addr, 0); |
| 541 | if (!folio) { |
| 542 | mmap_read_unlock(mm); |
| 543 | break; |
| 544 | } |
| 545 | /* arch_make_folio_accessible() needs a raised refcount. */ |
| 546 | folio_get(folio); |
| 547 | rc = arch_make_folio_accessible(folio); |
| 548 | folio_put(folio); |
| 549 | folio_walk_end(&fw, vma); |
| 550 | if (rc) |
| 551 | send_sig(SIGSEGV, current, 0); |
| 552 | mmap_read_unlock(mm); |
| 553 | break; |
| 554 | case KERNEL_FAULT: |
| 555 | folio = phys_to_folio(addr); |
| 556 | if (unlikely(!folio_try_get(folio))) |
| 557 | break; |
| 558 | rc = arch_make_folio_accessible(folio); |
| 559 | folio_put(folio); |
| 560 | if (rc) |
| 561 | BUG(); |
| 562 | break; |
| 563 | default: |
| 564 | unreachable(); |
| 565 | } |
| 566 | } |
| 567 | NOKPROBE_SYMBOL(do_secure_storage_access); |
| 568 | |
| 569 | void do_non_secure_storage_access(struct pt_regs *regs) |
| 570 | { |
| 571 | struct gmap *gmap = (struct gmap *)get_lowcore()->gmap; |
| 572 | unsigned long gaddr = get_fault_address(regs); |
| 573 | |
| 574 | if (WARN_ON_ONCE(get_fault_type(regs) != GMAP_FAULT)) |
| 575 | return handle_fault_error_nolock(regs, SEGV_MAPERR); |
| 576 | if (gmap_convert_to_secure(gmap, gaddr) == -EINVAL) |
| 577 | send_sig(SIGSEGV, current, 0); |
| 578 | } |
| 579 | NOKPROBE_SYMBOL(do_non_secure_storage_access); |
| 580 | |
| 581 | void do_secure_storage_violation(struct pt_regs *regs) |
| 582 | { |
| 583 | struct gmap *gmap = (struct gmap *)get_lowcore()->gmap; |
| 584 | unsigned long gaddr = get_fault_address(regs); |
| 585 | |
| 586 | /* |
| 587 | * If the VM has been rebooted, its address space might still contain |
| 588 | * secure pages from the previous boot. |
| 589 | * Clear the page so it can be reused. |
| 590 | */ |
| 591 | if (!gmap_destroy_page(gmap, gaddr)) |
| 592 | return; |
| 593 | /* |
| 594 | * Either KVM messed up the secure guest mapping or the same |
| 595 | * page is mapped into multiple secure guests. |
| 596 | * |
| 597 | * This exception is only triggered when a guest 2 is running |
| 598 | * and can therefore never occur in kernel context. |
| 599 | */ |
| 600 | pr_warn_ratelimited("Secure storage violation in task: %s, pid %d\n", |
| 601 | current->comm, current->pid); |
| 602 | send_sig(SIGSEGV, current, 0); |
| 603 | } |
| 604 | |
| 605 | #endif /* CONFIG_PGSTE */ |