]>
Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
1da177e4 | 2 | * S390 version |
a53c8fab | 3 | * Copyright IBM Corp. 1999 |
1da177e4 LT |
4 | * Author(s): Hartmut Penner (hp@de.ibm.com) |
5 | * Ulrich Weigand (uweigand@de.ibm.com) | |
6 | * | |
7 | * Derived from "arch/i386/mm/fault.c" | |
8 | * Copyright (C) 1995 Linus Torvalds | |
9 | */ | |
10 | ||
052ff461 | 11 | #include <linux/kernel_stat.h> |
cdd6c482 | 12 | #include <linux/perf_event.h> |
1da177e4 LT |
13 | #include <linux/signal.h> |
14 | #include <linux/sched.h> | |
15 | #include <linux/kernel.h> | |
16 | #include <linux/errno.h> | |
17 | #include <linux/string.h> | |
18 | #include <linux/types.h> | |
19 | #include <linux/ptrace.h> | |
20 | #include <linux/mman.h> | |
21 | #include <linux/mm.h> | |
7757591a | 22 | #include <linux/compat.h> |
1da177e4 | 23 | #include <linux/smp.h> |
1eeb66a1 | 24 | #include <linux/kdebug.h> |
1da177e4 LT |
25 | #include <linux/init.h> |
26 | #include <linux/console.h> | |
27 | #include <linux/module.h> | |
28 | #include <linux/hardirq.h> | |
4ba069b8 | 29 | #include <linux/kprobes.h> |
be5ec363 | 30 | #include <linux/uaccess.h> |
53492b1d | 31 | #include <linux/hugetlb.h> |
cbb870c8 | 32 | #include <asm/asm-offsets.h> |
1da177e4 | 33 | #include <asm/pgtable.h> |
d7b250e2 | 34 | #include <asm/irq.h> |
6252d702 | 35 | #include <asm/mmu_context.h> |
a0616cde | 36 | #include <asm/facility.h> |
a806170e | 37 | #include "../kernel/entry.h" |
1da177e4 | 38 | |
347a8dc3 | 39 | #ifndef CONFIG_64BIT |
1da177e4 | 40 | #define __FAIL_ADDR_MASK 0x7ffff000 |
1da177e4 LT |
41 | #define __SUBCODE_MASK 0x0200 |
42 | #define __PF_RES_FIELD 0ULL | |
347a8dc3 | 43 | #else /* CONFIG_64BIT */ |
1da177e4 | 44 | #define __FAIL_ADDR_MASK -4096L |
1da177e4 LT |
45 | #define __SUBCODE_MASK 0x0600 |
46 | #define __PF_RES_FIELD 0x8000000000000000ULL | |
347a8dc3 | 47 | #endif /* CONFIG_64BIT */ |
1da177e4 | 48 | |
50d7280d MS |
49 | #define VM_FAULT_BADCONTEXT 0x010000 |
50 | #define VM_FAULT_BADMAP 0x020000 | |
51 | #define VM_FAULT_BADACCESS 0x040000 | |
a4f32bdb | 52 | #define VM_FAULT_SIGNAL 0x080000 |
50d7280d | 53 | |
a4f32bdb | 54 | static unsigned long store_indication __read_mostly; |
92f842ea | 55 | |
a4f32bdb HC |
56 | #ifdef CONFIG_64BIT |
57 | static int __init fault_init(void) | |
92f842ea | 58 | { |
a4f32bdb | 59 | if (test_facility(75)) |
92f842ea | 60 | store_indication = 0xc00; |
a4f32bdb | 61 | return 0; |
92f842ea | 62 | } |
a4f32bdb HC |
63 | early_initcall(fault_init); |
64 | #endif | |
92f842ea | 65 | |
7ecb344a | 66 | static inline int notify_page_fault(struct pt_regs *regs) |
10c1031f | 67 | { |
33464e3b CH |
68 | int ret = 0; |
69 | ||
70 | /* kprobe_running() needs smp_processor_id() */ | |
22e0a046 | 71 | if (kprobes_built_in() && !user_mode(regs)) { |
33464e3b CH |
72 | preempt_disable(); |
73 | if (kprobe_running() && kprobe_fault_handler(regs, 14)) | |
74 | ret = 1; | |
75 | preempt_enable(); | |
76 | } | |
33464e3b | 77 | return ret; |
4ba069b8 | 78 | } |
4ba069b8 | 79 | |
1da177e4 LT |
80 | |
81 | /* | |
82 | * Unlock any spinlocks which will prevent us from getting the | |
cefc8be8 | 83 | * message out. |
1da177e4 LT |
84 | */ |
85 | void bust_spinlocks(int yes) | |
86 | { | |
87 | if (yes) { | |
88 | oops_in_progress = 1; | |
89 | } else { | |
90 | int loglevel_save = console_loglevel; | |
91 | console_unblank(); | |
92 | oops_in_progress = 0; | |
93 | /* | |
94 | * OK, the message is on the console. Now we call printk() | |
95 | * without oops_in_progress set so that printk will give klogd | |
96 | * a poke. Hold onto your hats... | |
97 | */ | |
98 | console_loglevel = 15; | |
99 | printk(" "); | |
100 | console_loglevel = loglevel_save; | |
101 | } | |
102 | } | |
103 | ||
104 | /* | |
482b05dd | 105 | * Returns the address space associated with the fault. |
61365e13 | 106 | * Returns 0 for kernel space and 1 for user space. |
1da177e4 | 107 | */ |
61365e13 | 108 | static inline int user_space_fault(unsigned long trans_exc_code) |
1da177e4 LT |
109 | { |
110 | /* | |
61365e13 MS |
111 | * The lowest two bits of the translation exception |
112 | * identification indicate which paging table was used. | |
1da177e4 | 113 | */ |
61365e13 MS |
114 | trans_exc_code &= 3; |
115 | if (trans_exc_code == 2) | |
116 | /* Access via secondary space, set_fs setting decides */ | |
117 | return current->thread.mm_segment.ar4; | |
d1b0d842 | 118 | if (s390_user_mode == HOME_SPACE_MODE) |
61365e13 MS |
119 | /* User space if the access has been done via home space. */ |
120 | return trans_exc_code == 3; | |
121 | /* | |
122 | * If the user space is not the home space the kernel runs in home | |
123 | * space. Access via secondary space has already been covered, | |
124 | * access via primary space or access register is from user space | |
125 | * and access via home space is from the kernel. | |
126 | */ | |
127 | return trans_exc_code != 3; | |
1da177e4 LT |
128 | } |
129 | ||
aa33c8cb | 130 | static inline void report_user_fault(struct pt_regs *regs, long signr) |
ab3c68ee HC |
131 | { |
132 | if ((task_pid_nr(current) > 1) && !show_unhandled_signals) | |
133 | return; | |
134 | if (!unhandled_signal(current, signr)) | |
135 | return; | |
136 | if (!printk_ratelimit()) | |
137 | return; | |
aa33c8cb MS |
138 | printk(KERN_ALERT "User process fault: interruption code 0x%X ", |
139 | regs->int_code); | |
ab3c68ee | 140 | print_vma_addr(KERN_CONT "in ", regs->psw.addr & PSW_ADDR_INSN); |
aa33c8cb MS |
141 | printk(KERN_CONT "\n"); |
142 | printk(KERN_ALERT "failing address: %lX\n", | |
143 | regs->int_parm_long & __FAIL_ADDR_MASK); | |
ab3c68ee HC |
144 | show_regs(regs); |
145 | } | |
146 | ||
1da177e4 LT |
147 | /* |
148 | * Send SIGSEGV to task. This is an external routine | |
149 | * to keep the stack usage of do_page_fault small. | |
150 | */ | |
aa33c8cb | 151 | static noinline void do_sigsegv(struct pt_regs *regs, int si_code) |
1da177e4 LT |
152 | { |
153 | struct siginfo si; | |
154 | ||
aa33c8cb | 155 | report_user_fault(regs, SIGSEGV); |
1da177e4 LT |
156 | si.si_signo = SIGSEGV; |
157 | si.si_code = si_code; | |
aa33c8cb | 158 | si.si_addr = (void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK); |
1da177e4 LT |
159 | force_sig_info(SIGSEGV, &si, current); |
160 | } | |
161 | ||
aa33c8cb | 162 | static noinline void do_no_context(struct pt_regs *regs) |
10c1031f MS |
163 | { |
164 | const struct exception_table_entry *fixup; | |
61365e13 | 165 | unsigned long address; |
10c1031f MS |
166 | |
167 | /* Are we prepared to handle this kernel fault? */ | |
50d7280d | 168 | fixup = search_exception_tables(regs->psw.addr & PSW_ADDR_INSN); |
10c1031f | 169 | if (fixup) { |
eb608fb3 | 170 | regs->psw.addr = extable_fixup(fixup) | PSW_ADDR_AMODE; |
10c1031f MS |
171 | return; |
172 | } | |
173 | ||
174 | /* | |
175 | * Oops. The kernel tried to access some bad page. We'll have to | |
176 | * terminate things with extreme prejudice. | |
177 | */ | |
aa33c8cb MS |
178 | address = regs->int_parm_long & __FAIL_ADDR_MASK; |
179 | if (!user_space_fault(regs->int_parm_long)) | |
10c1031f MS |
180 | printk(KERN_ALERT "Unable to handle kernel pointer dereference" |
181 | " at virtual kernel address %p\n", (void *)address); | |
182 | else | |
183 | printk(KERN_ALERT "Unable to handle kernel paging request" | |
184 | " at virtual user address %p\n", (void *)address); | |
185 | ||
aa33c8cb | 186 | die(regs, "Oops"); |
10c1031f MS |
187 | do_exit(SIGKILL); |
188 | } | |
189 | ||
aa33c8cb | 190 | static noinline void do_low_address(struct pt_regs *regs) |
10c1031f MS |
191 | { |
192 | /* Low-address protection hit in kernel mode means | |
193 | NULL pointer write access in kernel mode. */ | |
194 | if (regs->psw.mask & PSW_MASK_PSTATE) { | |
195 | /* Low-address protection hit in user mode 'cannot happen'. */ | |
aa33c8cb | 196 | die (regs, "Low-address protection"); |
10c1031f MS |
197 | do_exit(SIGKILL); |
198 | } | |
199 | ||
aa33c8cb | 200 | do_no_context(regs); |
10c1031f MS |
201 | } |
202 | ||
aa33c8cb | 203 | static noinline void do_sigbus(struct pt_regs *regs) |
10c1031f MS |
204 | { |
205 | struct task_struct *tsk = current; | |
36bf9680 | 206 | struct siginfo si; |
10c1031f | 207 | |
10c1031f MS |
208 | /* |
209 | * Send a sigbus, regardless of whether we were in kernel | |
210 | * or user mode. | |
211 | */ | |
36bf9680 MS |
212 | si.si_signo = SIGBUS; |
213 | si.si_errno = 0; | |
214 | si.si_code = BUS_ADRERR; | |
aa33c8cb | 215 | si.si_addr = (void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK); |
36bf9680 | 216 | force_sig_info(SIGBUS, &si, tsk); |
10c1031f MS |
217 | } |
218 | ||
aa33c8cb | 219 | static noinline void do_fault_error(struct pt_regs *regs, int fault) |
50d7280d MS |
220 | { |
221 | int si_code; | |
222 | ||
223 | switch (fault) { | |
224 | case VM_FAULT_BADACCESS: | |
50d7280d MS |
225 | case VM_FAULT_BADMAP: |
226 | /* Bad memory access. Check if it is kernel or user space. */ | |
7d256175 | 227 | if (user_mode(regs)) { |
50d7280d MS |
228 | /* User mode accesses just cause a SIGSEGV */ |
229 | si_code = (fault == VM_FAULT_BADMAP) ? | |
230 | SEGV_MAPERR : SEGV_ACCERR; | |
aa33c8cb | 231 | do_sigsegv(regs, si_code); |
50d7280d MS |
232 | return; |
233 | } | |
234 | case VM_FAULT_BADCONTEXT: | |
aa33c8cb | 235 | do_no_context(regs); |
50d7280d | 236 | break; |
f2c76e3b HC |
237 | case VM_FAULT_SIGNAL: |
238 | if (!user_mode(regs)) | |
239 | do_no_context(regs); | |
240 | break; | |
50d7280d | 241 | default: /* fault & VM_FAULT_ERROR */ |
99583181 | 242 | if (fault & VM_FAULT_OOM) { |
7d256175 | 243 | if (!user_mode(regs)) |
aa33c8cb | 244 | do_no_context(regs); |
99583181 HC |
245 | else |
246 | pagefault_out_of_memory(); | |
247 | } else if (fault & VM_FAULT_SIGBUS) { | |
50d7280d | 248 | /* Kernel mode? Handle exceptions or die */ |
7d256175 | 249 | if (!user_mode(regs)) |
aa33c8cb | 250 | do_no_context(regs); |
36bf9680 | 251 | else |
aa33c8cb | 252 | do_sigbus(regs); |
50d7280d MS |
253 | } else |
254 | BUG(); | |
255 | break; | |
256 | } | |
257 | } | |
258 | ||
1da177e4 LT |
259 | /* |
260 | * This routine handles page faults. It determines the address, | |
261 | * and the problem, and then passes it off to one of the appropriate | |
262 | * routines. | |
263 | * | |
50d7280d | 264 | * interruption code (int_code): |
1da177e4 LT |
265 | * 04 Protection -> Write-Protection (suprression) |
266 | * 10 Segment translation -> Not present (nullification) | |
267 | * 11 Page translation -> Not present (nullification) | |
268 | * 3b Region third trans. -> Not present (nullification) | |
269 | */ | |
aa33c8cb | 270 | static inline int do_exception(struct pt_regs *regs, int access) |
1da177e4 | 271 | { |
10c1031f MS |
272 | struct task_struct *tsk; |
273 | struct mm_struct *mm; | |
274 | struct vm_area_struct *vma; | |
aa33c8cb | 275 | unsigned long trans_exc_code; |
10c1031f | 276 | unsigned long address; |
33ce6140 HC |
277 | unsigned int flags; |
278 | int fault; | |
1da177e4 | 279 | |
39efd4ec MS |
280 | tsk = current; |
281 | /* | |
282 | * The instruction that caused the program check has | |
283 | * been nullified. Don't signal single step via SIGTRAP. | |
284 | */ | |
285 | clear_tsk_thread_flag(tsk, TIF_PER_TRAP); | |
286 | ||
7ecb344a | 287 | if (notify_page_fault(regs)) |
50d7280d | 288 | return 0; |
4ba069b8 | 289 | |
10c1031f | 290 | mm = tsk->mm; |
aa33c8cb | 291 | trans_exc_code = regs->int_parm_long; |
1da177e4 | 292 | |
1da177e4 LT |
293 | /* |
294 | * Verify that the fault happened in user space, that | |
295 | * we are not in an interrupt and that there is a | |
296 | * user context. | |
297 | */ | |
50d7280d | 298 | fault = VM_FAULT_BADCONTEXT; |
61365e13 | 299 | if (unlikely(!user_space_fault(trans_exc_code) || in_atomic() || !mm)) |
50d7280d | 300 | goto out; |
1da177e4 | 301 | |
61365e13 | 302 | address = trans_exc_code & __FAIL_ADDR_MASK; |
a8b0ca17 | 303 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); |
f2c76e3b | 304 | flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; |
759496ba JW |
305 | if (user_mode(regs)) |
306 | flags |= FAULT_FLAG_USER; | |
33ce6140 HC |
307 | if (access == VM_WRITE || (trans_exc_code & store_indication) == 0x400) |
308 | flags |= FAULT_FLAG_WRITE; | |
10c1031f | 309 | down_read(&mm->mmap_sem); |
1da177e4 | 310 | |
e5992f2e | 311 | #ifdef CONFIG_PGSTE |
5e8010cb | 312 | if ((current->flags & PF_VCPU) && S390_lowcore.gmap) { |
499069e1 | 313 | address = __gmap_fault(address, |
e5992f2e MS |
314 | (struct gmap *) S390_lowcore.gmap); |
315 | if (address == -EFAULT) { | |
316 | fault = VM_FAULT_BADMAP; | |
317 | goto out_up; | |
318 | } | |
319 | if (address == -ENOMEM) { | |
320 | fault = VM_FAULT_OOM; | |
321 | goto out_up; | |
322 | } | |
323 | } | |
324 | #endif | |
325 | ||
326 | retry: | |
50d7280d | 327 | fault = VM_FAULT_BADMAP; |
482b05dd GS |
328 | vma = find_vma(mm, address); |
329 | if (!vma) | |
50d7280d | 330 | goto out_up; |
c1821c2e | 331 | |
50d7280d MS |
332 | if (unlikely(vma->vm_start > address)) { |
333 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
334 | goto out_up; | |
335 | if (expand_stack(vma, address)) | |
336 | goto out_up; | |
337 | } | |
338 | ||
339 | /* | |
340 | * Ok, we have a good vm_area for this memory access, so | |
341 | * we can handle it.. | |
342 | */ | |
343 | fault = VM_FAULT_BADACCESS; | |
1ab947de | 344 | if (unlikely(!(vma->vm_flags & access))) |
50d7280d | 345 | goto out_up; |
1da177e4 | 346 | |
53492b1d GS |
347 | if (is_vm_hugetlb_page(vma)) |
348 | address &= HPAGE_MASK; | |
1da177e4 LT |
349 | /* |
350 | * If for any reason at all we couldn't handle the fault, | |
351 | * make sure we exit gracefully rather than endlessly redo | |
352 | * the fault. | |
353 | */ | |
33ce6140 | 354 | fault = handle_mm_fault(mm, vma, address, flags); |
f2c76e3b HC |
355 | /* No reason to continue if interrupted by SIGKILL. */ |
356 | if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) { | |
357 | fault = VM_FAULT_SIGNAL; | |
358 | goto out; | |
359 | } | |
50d7280d MS |
360 | if (unlikely(fault & VM_FAULT_ERROR)) |
361 | goto out_up; | |
362 | ||
33ce6140 HC |
363 | /* |
364 | * Major/minor page fault accounting is only done on the | |
365 | * initial attempt. If we go through a retry, it is extremely | |
366 | * likely that the page will be found in page cache at that point. | |
367 | */ | |
368 | if (flags & FAULT_FLAG_ALLOW_RETRY) { | |
369 | if (fault & VM_FAULT_MAJOR) { | |
370 | tsk->maj_flt++; | |
a8b0ca17 | 371 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, |
33ce6140 HC |
372 | regs, address); |
373 | } else { | |
374 | tsk->min_flt++; | |
a8b0ca17 | 375 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, |
33ce6140 HC |
376 | regs, address); |
377 | } | |
378 | if (fault & VM_FAULT_RETRY) { | |
379 | /* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk | |
380 | * of starvation. */ | |
381 | flags &= ~FAULT_FLAG_ALLOW_RETRY; | |
45cac65b | 382 | flags |= FAULT_FLAG_TRIED; |
e5992f2e | 383 | down_read(&mm->mmap_sem); |
33ce6140 HC |
384 | goto retry; |
385 | } | |
bde69af2 | 386 | } |
50d7280d MS |
387 | fault = 0; |
388 | out_up: | |
10c1031f | 389 | up_read(&mm->mmap_sem); |
50d7280d MS |
390 | out: |
391 | return fault; | |
1da177e4 LT |
392 | } |
393 | ||
aa33c8cb | 394 | void __kprobes do_protection_exception(struct pt_regs *regs) |
1da177e4 | 395 | { |
aa33c8cb | 396 | unsigned long trans_exc_code; |
50d7280d | 397 | int fault; |
61365e13 | 398 | |
aa33c8cb | 399 | trans_exc_code = regs->int_parm_long; |
f752ac4d MS |
400 | /* |
401 | * Protection exceptions are suppressing, decrement psw address. | |
402 | * The exception to this rule are aborted transactions, for these | |
403 | * the PSW already points to the correct location. | |
404 | */ | |
405 | if (!(regs->int_code & 0x200)) | |
406 | regs->psw.addr = __rewind_psw(regs->psw, regs->int_code >> 16); | |
10c1031f MS |
407 | /* |
408 | * Check for low-address protection. This needs to be treated | |
409 | * as a special case because the translation exception code | |
410 | * field is not guaranteed to contain valid data in this case. | |
411 | */ | |
61365e13 | 412 | if (unlikely(!(trans_exc_code & 4))) { |
aa33c8cb | 413 | do_low_address(regs); |
10c1031f MS |
414 | return; |
415 | } | |
aa33c8cb | 416 | fault = do_exception(regs, VM_WRITE); |
50d7280d | 417 | if (unlikely(fault)) |
aa33c8cb | 418 | do_fault_error(regs, fault); |
1da177e4 LT |
419 | } |
420 | ||
aa33c8cb | 421 | void __kprobes do_dat_exception(struct pt_regs *regs) |
1da177e4 | 422 | { |
1ab947de | 423 | int access, fault; |
50d7280d | 424 | |
1ab947de | 425 | access = VM_READ | VM_EXEC | VM_WRITE; |
aa33c8cb | 426 | fault = do_exception(regs, access); |
50d7280d | 427 | if (unlikely(fault)) |
aa33c8cb | 428 | do_fault_error(regs, fault); |
1da177e4 LT |
429 | } |
430 | ||
6252d702 | 431 | #ifdef CONFIG_64BIT |
aa33c8cb | 432 | void __kprobes do_asce_exception(struct pt_regs *regs) |
6252d702 | 433 | { |
50d7280d | 434 | struct mm_struct *mm = current->mm; |
6252d702 | 435 | struct vm_area_struct *vma; |
aa33c8cb | 436 | unsigned long trans_exc_code; |
6252d702 | 437 | |
39efd4ec MS |
438 | /* |
439 | * The instruction that caused the program check has | |
440 | * been nullified. Don't signal single step via SIGTRAP. | |
441 | */ | |
442 | clear_tsk_thread_flag(current, TIF_PER_TRAP); | |
443 | ||
aa33c8cb | 444 | trans_exc_code = regs->int_parm_long; |
61365e13 | 445 | if (unlikely(!user_space_fault(trans_exc_code) || in_atomic() || !mm)) |
6252d702 MS |
446 | goto no_context; |
447 | ||
6252d702 | 448 | down_read(&mm->mmap_sem); |
50d7280d | 449 | vma = find_vma(mm, trans_exc_code & __FAIL_ADDR_MASK); |
6252d702 MS |
450 | up_read(&mm->mmap_sem); |
451 | ||
452 | if (vma) { | |
453 | update_mm(mm, current); | |
454 | return; | |
455 | } | |
456 | ||
457 | /* User mode accesses just cause a SIGSEGV */ | |
7d256175 | 458 | if (user_mode(regs)) { |
aa33c8cb | 459 | do_sigsegv(regs, SEGV_MAPERR); |
6252d702 MS |
460 | return; |
461 | } | |
462 | ||
463 | no_context: | |
aa33c8cb | 464 | do_no_context(regs); |
6252d702 MS |
465 | } |
466 | #endif | |
467 | ||
1e54622e | 468 | int __handle_fault(unsigned long uaddr, unsigned long pgm_int_code, int write) |
6c1e3e79 GS |
469 | { |
470 | struct pt_regs regs; | |
471 | int access, fault; | |
472 | ||
008c2e8f | 473 | /* Emulate a uaccess fault from kernel mode. */ |
b50511e4 | 474 | regs.psw.mask = psw_kernel_bits | PSW_MASK_DAT | PSW_MASK_MCHECK; |
6c1e3e79 GS |
475 | if (!irqs_disabled()) |
476 | regs.psw.mask |= PSW_MASK_IO | PSW_MASK_EXT; | |
477 | regs.psw.addr = (unsigned long) __builtin_return_address(0); | |
478 | regs.psw.addr |= PSW_ADDR_AMODE; | |
aa33c8cb MS |
479 | regs.int_code = pgm_int_code; |
480 | regs.int_parm_long = (uaddr & PAGE_MASK) | 2; | |
1e54622e | 481 | access = write ? VM_WRITE : VM_READ; |
aa33c8cb | 482 | fault = do_exception(®s, access); |
008c2e8f HC |
483 | /* |
484 | * Since the fault happened in kernel mode while performing a uaccess | |
485 | * all we need to do now is emulating a fixup in case "fault" is not | |
486 | * zero. | |
487 | * For the calling uaccess functions this results always in -EFAULT. | |
488 | */ | |
6c1e3e79 GS |
489 | return fault ? -EFAULT : 0; |
490 | } | |
491 | ||
1da177e4 LT |
492 | #ifdef CONFIG_PFAULT |
493 | /* | |
494 | * 'pfault' pseudo page faults routines. | |
495 | */ | |
fb0a9d7e | 496 | static int pfault_disable; |
1da177e4 LT |
497 | |
498 | static int __init nopfault(char *str) | |
499 | { | |
500 | pfault_disable = 1; | |
501 | return 1; | |
502 | } | |
503 | ||
504 | __setup("nopfault", nopfault); | |
505 | ||
7dd8fe1f HC |
506 | struct pfault_refbk { |
507 | u16 refdiagc; | |
508 | u16 reffcode; | |
509 | u16 refdwlen; | |
510 | u16 refversn; | |
511 | u64 refgaddr; | |
512 | u64 refselmk; | |
513 | u64 refcmpmk; | |
514 | u64 reserved; | |
515 | } __attribute__ ((packed, aligned(8))); | |
1da177e4 LT |
516 | |
517 | int pfault_init(void) | |
518 | { | |
7dd8fe1f HC |
519 | struct pfault_refbk refbk = { |
520 | .refdiagc = 0x258, | |
521 | .reffcode = 0, | |
522 | .refdwlen = 5, | |
523 | .refversn = 2, | |
524 | .refgaddr = __LC_CURRENT_PID, | |
525 | .refselmk = 1ULL << 48, | |
526 | .refcmpmk = 1ULL << 48, | |
527 | .reserved = __PF_RES_FIELD }; | |
1da177e4 LT |
528 | int rc; |
529 | ||
f32269a0 | 530 | if (pfault_disable) |
1da177e4 | 531 | return -1; |
94c12cc7 MS |
532 | asm volatile( |
533 | " diag %1,%0,0x258\n" | |
534 | "0: j 2f\n" | |
535 | "1: la %0,8\n" | |
1da177e4 | 536 | "2:\n" |
94c12cc7 MS |
537 | EX_TABLE(0b,1b) |
538 | : "=d" (rc) : "a" (&refbk), "m" (refbk) : "cc"); | |
1da177e4 LT |
539 | return rc; |
540 | } | |
541 | ||
542 | void pfault_fini(void) | |
543 | { | |
7dd8fe1f HC |
544 | struct pfault_refbk refbk = { |
545 | .refdiagc = 0x258, | |
546 | .reffcode = 1, | |
547 | .refdwlen = 5, | |
548 | .refversn = 2, | |
549 | }; | |
1da177e4 | 550 | |
f32269a0 | 551 | if (pfault_disable) |
1da177e4 | 552 | return; |
94c12cc7 MS |
553 | asm volatile( |
554 | " diag %0,0,0x258\n" | |
1da177e4 | 555 | "0:\n" |
94c12cc7 MS |
556 | EX_TABLE(0b,0b) |
557 | : : "a" (&refbk), "m" (refbk) : "cc"); | |
1da177e4 LT |
558 | } |
559 | ||
f2db2e6c HC |
560 | static DEFINE_SPINLOCK(pfault_lock); |
561 | static LIST_HEAD(pfault_list); | |
562 | ||
fde15c3a | 563 | static void pfault_interrupt(struct ext_code ext_code, |
f6649a7e | 564 | unsigned int param32, unsigned long param64) |
1da177e4 LT |
565 | { |
566 | struct task_struct *tsk; | |
567 | __u16 subcode; | |
f2db2e6c | 568 | pid_t pid; |
1da177e4 LT |
569 | |
570 | /* | |
571 | * Get the external interruption subcode & pfault | |
572 | * initial/completion signal bit. VM stores this | |
573 | * in the 'cpu address' field associated with the | |
574 | * external interrupt. | |
575 | */ | |
fde15c3a | 576 | subcode = ext_code.subcode; |
1da177e4 LT |
577 | if ((subcode & 0xff00) != __SUBCODE_MASK) |
578 | return; | |
420f42ec | 579 | inc_irq_stat(IRQEXT_PFL); |
54c27791 HC |
580 | /* Get the token (= pid of the affected task). */ |
581 | pid = sizeof(void *) == 4 ? param32 : param64; | |
582 | rcu_read_lock(); | |
583 | tsk = find_task_by_pid_ns(pid, &init_pid_ns); | |
584 | if (tsk) | |
585 | get_task_struct(tsk); | |
586 | rcu_read_unlock(); | |
587 | if (!tsk) | |
588 | return; | |
f2db2e6c | 589 | spin_lock(&pfault_lock); |
1da177e4 LT |
590 | if (subcode & 0x0080) { |
591 | /* signal bit is set -> a page has been swapped in by VM */ | |
f2db2e6c | 592 | if (tsk->thread.pfault_wait == 1) { |
1da177e4 LT |
593 | /* Initial interrupt was faster than the completion |
594 | * interrupt. pfault_wait is valid. Set pfault_wait | |
595 | * back to zero and wake up the process. This can | |
596 | * safely be done because the task is still sleeping | |
b6d09449 | 597 | * and can't produce new pfaults. */ |
1da177e4 | 598 | tsk->thread.pfault_wait = 0; |
f2db2e6c | 599 | list_del(&tsk->thread.list); |
1da177e4 | 600 | wake_up_process(tsk); |
d5e50a51 | 601 | put_task_struct(tsk); |
f2db2e6c HC |
602 | } else { |
603 | /* Completion interrupt was faster than initial | |
604 | * interrupt. Set pfault_wait to -1 so the initial | |
fa2fb2f4 HC |
605 | * interrupt doesn't put the task to sleep. |
606 | * If the task is not running, ignore the completion | |
607 | * interrupt since it must be a leftover of a PFAULT | |
608 | * CANCEL operation which didn't remove all pending | |
609 | * completion interrupts. */ | |
610 | if (tsk->state == TASK_RUNNING) | |
611 | tsk->thread.pfault_wait = -1; | |
1da177e4 LT |
612 | } |
613 | } else { | |
614 | /* signal bit not set -> a real page is missing. */ | |
d49f47f8 HC |
615 | if (WARN_ON_ONCE(tsk != current)) |
616 | goto out; | |
d5e50a51 HC |
617 | if (tsk->thread.pfault_wait == 1) { |
618 | /* Already on the list with a reference: put to sleep */ | |
0a16ba78 | 619 | __set_task_state(tsk, TASK_UNINTERRUPTIBLE); |
d5e50a51 HC |
620 | set_tsk_need_resched(tsk); |
621 | } else if (tsk->thread.pfault_wait == -1) { | |
1da177e4 | 622 | /* Completion interrupt was faster than the initial |
f2db2e6c HC |
623 | * interrupt (pfault_wait == -1). Set pfault_wait |
624 | * back to zero and exit. */ | |
1da177e4 | 625 | tsk->thread.pfault_wait = 0; |
f2db2e6c HC |
626 | } else { |
627 | /* Initial interrupt arrived before completion | |
d5e50a51 HC |
628 | * interrupt. Let the task sleep. |
629 | * An extra task reference is needed since a different | |
630 | * cpu may set the task state to TASK_RUNNING again | |
631 | * before the scheduler is reached. */ | |
632 | get_task_struct(tsk); | |
f2db2e6c HC |
633 | tsk->thread.pfault_wait = 1; |
634 | list_add(&tsk->thread.list, &pfault_list); | |
0a16ba78 | 635 | __set_task_state(tsk, TASK_UNINTERRUPTIBLE); |
1da177e4 | 636 | set_tsk_need_resched(tsk); |
f2db2e6c HC |
637 | } |
638 | } | |
d49f47f8 | 639 | out: |
f2db2e6c | 640 | spin_unlock(&pfault_lock); |
54c27791 | 641 | put_task_struct(tsk); |
f2db2e6c HC |
642 | } |
643 | ||
e2741f17 PG |
644 | static int pfault_cpu_notify(struct notifier_block *self, unsigned long action, |
645 | void *hcpu) | |
f2db2e6c HC |
646 | { |
647 | struct thread_struct *thread, *next; | |
648 | struct task_struct *tsk; | |
649 | ||
1c725922 | 650 | switch (action & ~CPU_TASKS_FROZEN) { |
f2db2e6c | 651 | case CPU_DEAD: |
f2db2e6c HC |
652 | spin_lock_irq(&pfault_lock); |
653 | list_for_each_entry_safe(thread, next, &pfault_list, list) { | |
654 | thread->pfault_wait = 0; | |
655 | list_del(&thread->list); | |
656 | tsk = container_of(thread, struct task_struct, thread); | |
657 | wake_up_process(tsk); | |
d5e50a51 | 658 | put_task_struct(tsk); |
f2db2e6c HC |
659 | } |
660 | spin_unlock_irq(&pfault_lock); | |
661 | break; | |
662 | default: | |
663 | break; | |
1da177e4 | 664 | } |
f2db2e6c | 665 | return NOTIFY_OK; |
1da177e4 | 666 | } |
1da177e4 | 667 | |
fb0a9d7e | 668 | static int __init pfault_irq_init(void) |
29b08d2b | 669 | { |
fb0a9d7e | 670 | int rc; |
29b08d2b | 671 | |
fb0a9d7e | 672 | rc = register_external_interrupt(0x2603, pfault_interrupt); |
7dd8fe1f HC |
673 | if (rc) |
674 | goto out_extint; | |
675 | rc = pfault_init() == 0 ? 0 : -EOPNOTSUPP; | |
676 | if (rc) | |
677 | goto out_pfault; | |
82003c3e | 678 | irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL); |
7dd8fe1f HC |
679 | hotcpu_notifier(pfault_cpu_notify, 0); |
680 | return 0; | |
29b08d2b | 681 | |
7dd8fe1f | 682 | out_pfault: |
fb0a9d7e | 683 | unregister_external_interrupt(0x2603, pfault_interrupt); |
7dd8fe1f HC |
684 | out_extint: |
685 | pfault_disable = 1; | |
686 | return rc; | |
29b08d2b | 687 | } |
fb0a9d7e HC |
688 | early_initcall(pfault_irq_init); |
689 | ||
7dd8fe1f | 690 | #endif /* CONFIG_PFAULT */ |