Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * arch/s390/mm/fault.c |
| 3 | * |
| 4 | * S390 version |
| 5 | * Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation |
| 6 | * Author(s): Hartmut Penner (hp@de.ibm.com) |
| 7 | * Ulrich Weigand (uweigand@de.ibm.com) |
| 8 | * |
| 9 | * Derived from "arch/i386/mm/fault.c" |
| 10 | * Copyright (C) 1995 Linus Torvalds |
| 11 | */ |
| 12 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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> |
| 22 | #include <linux/smp.h> |
| 23 | #include <linux/smp_lock.h> |
| 24 | #include <linux/init.h> |
| 25 | #include <linux/console.h> |
| 26 | #include <linux/module.h> |
| 27 | #include <linux/hardirq.h> |
Michael Grundy | 4ba069b | 2006-09-20 15:58:39 +0200 | [diff] [blame] | 28 | #include <linux/kprobes.h> |
Martin Schwidefsky | be5ec36 | 2007-04-27 16:01:44 +0200 | [diff] [blame^] | 29 | #include <linux/uaccess.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 30 | |
| 31 | #include <asm/system.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 32 | #include <asm/pgtable.h> |
Michael Grundy | 4ba069b | 2006-09-20 15:58:39 +0200 | [diff] [blame] | 33 | #include <asm/kdebug.h> |
Heiko Carstens | 29b08d2 | 2006-12-04 15:40:40 +0100 | [diff] [blame] | 34 | #include <asm/s390_ext.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | |
Martin Schwidefsky | 347a8dc | 2006-01-06 00:19:28 -0800 | [diff] [blame] | 36 | #ifndef CONFIG_64BIT |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 37 | #define __FAIL_ADDR_MASK 0x7ffff000 |
| 38 | #define __FIXUP_MASK 0x7fffffff |
| 39 | #define __SUBCODE_MASK 0x0200 |
| 40 | #define __PF_RES_FIELD 0ULL |
Martin Schwidefsky | 347a8dc | 2006-01-06 00:19:28 -0800 | [diff] [blame] | 41 | #else /* CONFIG_64BIT */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 42 | #define __FAIL_ADDR_MASK -4096L |
| 43 | #define __FIXUP_MASK ~0L |
| 44 | #define __SUBCODE_MASK 0x0600 |
| 45 | #define __PF_RES_FIELD 0x8000000000000000ULL |
Martin Schwidefsky | 347a8dc | 2006-01-06 00:19:28 -0800 | [diff] [blame] | 46 | #endif /* CONFIG_64BIT */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 47 | |
| 48 | #ifdef CONFIG_SYSCTL |
| 49 | extern int sysctl_userprocess_debug; |
| 50 | #endif |
| 51 | |
| 52 | extern void die(const char *,struct pt_regs *,long); |
| 53 | |
Michael Grundy | 4ba069b | 2006-09-20 15:58:39 +0200 | [diff] [blame] | 54 | #ifdef CONFIG_KPROBES |
Heiko Carstens | 2b67fc4 | 2007-02-05 21:16:47 +0100 | [diff] [blame] | 55 | static ATOMIC_NOTIFIER_HEAD(notify_page_fault_chain); |
Michael Grundy | 4ba069b | 2006-09-20 15:58:39 +0200 | [diff] [blame] | 56 | int register_page_fault_notifier(struct notifier_block *nb) |
| 57 | { |
| 58 | return atomic_notifier_chain_register(¬ify_page_fault_chain, nb); |
| 59 | } |
| 60 | |
| 61 | int unregister_page_fault_notifier(struct notifier_block *nb) |
| 62 | { |
| 63 | return atomic_notifier_chain_unregister(¬ify_page_fault_chain, nb); |
| 64 | } |
| 65 | |
Martin Schwidefsky | 10c1031 | 2007-04-27 16:01:43 +0200 | [diff] [blame] | 66 | static int __kprobes __notify_page_fault(struct pt_regs *regs, long err) |
Michael Grundy | 4ba069b | 2006-09-20 15:58:39 +0200 | [diff] [blame] | 67 | { |
Martin Schwidefsky | 10c1031 | 2007-04-27 16:01:43 +0200 | [diff] [blame] | 68 | struct die_args args = { .str = "page fault", |
| 69 | .trapnr = 14, |
| 70 | .signr = SIGSEGV }; |
| 71 | args.regs = regs; |
| 72 | args.err = err; |
| 73 | return atomic_notifier_call_chain(¬ify_page_fault_chain, |
| 74 | DIE_PAGE_FAULT, &args); |
| 75 | } |
| 76 | |
| 77 | static inline int notify_page_fault(struct pt_regs *regs, long err) |
| 78 | { |
| 79 | if (unlikely(kprobe_running())) |
| 80 | return __notify_page_fault(regs, err); |
| 81 | return NOTIFY_DONE; |
Michael Grundy | 4ba069b | 2006-09-20 15:58:39 +0200 | [diff] [blame] | 82 | } |
| 83 | #else |
Martin Schwidefsky | 10c1031 | 2007-04-27 16:01:43 +0200 | [diff] [blame] | 84 | static inline int notify_page_fault(struct pt_regs *regs, long err) |
Michael Grundy | 4ba069b | 2006-09-20 15:58:39 +0200 | [diff] [blame] | 85 | { |
| 86 | return NOTIFY_DONE; |
| 87 | } |
| 88 | #endif |
| 89 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 90 | |
| 91 | /* |
| 92 | * Unlock any spinlocks which will prevent us from getting the |
Kirill Korotaev | cefc8be | 2007-02-10 01:46:18 -0800 | [diff] [blame] | 93 | * message out. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 94 | */ |
| 95 | void bust_spinlocks(int yes) |
| 96 | { |
| 97 | if (yes) { |
| 98 | oops_in_progress = 1; |
| 99 | } else { |
| 100 | int loglevel_save = console_loglevel; |
| 101 | console_unblank(); |
| 102 | oops_in_progress = 0; |
| 103 | /* |
| 104 | * OK, the message is on the console. Now we call printk() |
| 105 | * without oops_in_progress set so that printk will give klogd |
| 106 | * a poke. Hold onto your hats... |
| 107 | */ |
| 108 | console_loglevel = 15; |
| 109 | printk(" "); |
| 110 | console_loglevel = loglevel_save; |
| 111 | } |
| 112 | } |
| 113 | |
| 114 | /* |
Gerald Schaefer | 482b05d | 2007-03-05 23:35:54 +0100 | [diff] [blame] | 115 | * Returns the address space associated with the fault. |
| 116 | * Returns 0 for kernel space, 1 for user space and |
| 117 | * 2 for code execution in user space with noexec=on. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 118 | */ |
Gerald Schaefer | 482b05d | 2007-03-05 23:35:54 +0100 | [diff] [blame] | 119 | static inline int check_space(struct task_struct *tsk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 120 | { |
| 121 | /* |
Gerald Schaefer | 482b05d | 2007-03-05 23:35:54 +0100 | [diff] [blame] | 122 | * The lowest two bits of S390_lowcore.trans_exc_code |
| 123 | * indicate which paging table was used. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 124 | */ |
Gerald Schaefer | 482b05d | 2007-03-05 23:35:54 +0100 | [diff] [blame] | 125 | int desc = S390_lowcore.trans_exc_code & 3; |
| 126 | |
| 127 | if (desc == 3) /* Home Segment Table Descriptor */ |
| 128 | return switch_amode == 0; |
| 129 | if (desc == 2) /* Secondary Segment Table Descriptor */ |
| 130 | return tsk->thread.mm_segment.ar4; |
| 131 | #ifdef CONFIG_S390_SWITCH_AMODE |
| 132 | if (unlikely(desc == 1)) { /* STD determined via access register */ |
| 133 | /* %a0 always indicates primary space. */ |
| 134 | if (S390_lowcore.exc_access_id != 0) { |
| 135 | save_access_regs(tsk->thread.acrs); |
| 136 | /* |
| 137 | * An alet of 0 indicates primary space. |
| 138 | * An alet of 1 indicates secondary space. |
| 139 | * Any other alet values generate an |
| 140 | * alen-translation exception. |
| 141 | */ |
| 142 | if (tsk->thread.acrs[S390_lowcore.exc_access_id]) |
| 143 | return tsk->thread.mm_segment.ar4; |
| 144 | } |
| 145 | } |
| 146 | #endif |
| 147 | /* Primary Segment Table Descriptor */ |
| 148 | return switch_amode << s390_noexec; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 149 | } |
| 150 | |
| 151 | /* |
| 152 | * Send SIGSEGV to task. This is an external routine |
| 153 | * to keep the stack usage of do_page_fault small. |
| 154 | */ |
| 155 | static void do_sigsegv(struct pt_regs *regs, unsigned long error_code, |
| 156 | int si_code, unsigned long address) |
| 157 | { |
| 158 | struct siginfo si; |
| 159 | |
| 160 | #if defined(CONFIG_SYSCTL) || defined(CONFIG_PROCESS_DEBUG) |
| 161 | #if defined(CONFIG_SYSCTL) |
| 162 | if (sysctl_userprocess_debug) |
| 163 | #endif |
| 164 | { |
| 165 | printk("User process fault: interruption code 0x%lX\n", |
| 166 | error_code); |
| 167 | printk("failing address: %lX\n", address); |
| 168 | show_regs(regs); |
| 169 | } |
| 170 | #endif |
| 171 | si.si_signo = SIGSEGV; |
| 172 | si.si_code = si_code; |
Heiko Carstens | d2c993d | 2006-07-12 16:41:55 +0200 | [diff] [blame] | 173 | si.si_addr = (void __user *) address; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 174 | force_sig_info(SIGSEGV, &si, current); |
| 175 | } |
| 176 | |
Martin Schwidefsky | 10c1031 | 2007-04-27 16:01:43 +0200 | [diff] [blame] | 177 | static void do_no_context(struct pt_regs *regs, unsigned long error_code, |
| 178 | unsigned long address) |
| 179 | { |
| 180 | const struct exception_table_entry *fixup; |
| 181 | |
| 182 | /* Are we prepared to handle this kernel fault? */ |
| 183 | fixup = search_exception_tables(regs->psw.addr & __FIXUP_MASK); |
| 184 | if (fixup) { |
| 185 | regs->psw.addr = fixup->fixup | PSW_ADDR_AMODE; |
| 186 | return; |
| 187 | } |
| 188 | |
| 189 | /* |
| 190 | * Oops. The kernel tried to access some bad page. We'll have to |
| 191 | * terminate things with extreme prejudice. |
| 192 | */ |
| 193 | if (check_space(current) == 0) |
| 194 | printk(KERN_ALERT "Unable to handle kernel pointer dereference" |
| 195 | " at virtual kernel address %p\n", (void *)address); |
| 196 | else |
| 197 | printk(KERN_ALERT "Unable to handle kernel paging request" |
| 198 | " at virtual user address %p\n", (void *)address); |
| 199 | |
| 200 | die("Oops", regs, error_code); |
| 201 | do_exit(SIGKILL); |
| 202 | } |
| 203 | |
| 204 | static void do_low_address(struct pt_regs *regs, unsigned long error_code) |
| 205 | { |
| 206 | /* Low-address protection hit in kernel mode means |
| 207 | NULL pointer write access in kernel mode. */ |
| 208 | if (regs->psw.mask & PSW_MASK_PSTATE) { |
| 209 | /* Low-address protection hit in user mode 'cannot happen'. */ |
| 210 | die ("Low-address protection", regs, error_code); |
| 211 | do_exit(SIGKILL); |
| 212 | } |
| 213 | |
| 214 | do_no_context(regs, error_code, 0); |
| 215 | } |
| 216 | |
| 217 | /* |
| 218 | * We ran out of memory, or some other thing happened to us that made |
| 219 | * us unable to handle the page fault gracefully. |
| 220 | */ |
| 221 | static int do_out_of_memory(struct pt_regs *regs, unsigned long error_code, |
| 222 | unsigned long address) |
| 223 | { |
| 224 | struct task_struct *tsk = current; |
| 225 | struct mm_struct *mm = tsk->mm; |
| 226 | |
| 227 | up_read(&mm->mmap_sem); |
| 228 | if (is_init(tsk)) { |
| 229 | yield(); |
| 230 | down_read(&mm->mmap_sem); |
| 231 | return 1; |
| 232 | } |
| 233 | printk("VM: killing process %s\n", tsk->comm); |
| 234 | if (regs->psw.mask & PSW_MASK_PSTATE) |
| 235 | do_exit(SIGKILL); |
| 236 | do_no_context(regs, error_code, address); |
| 237 | return 0; |
| 238 | } |
| 239 | |
| 240 | static void do_sigbus(struct pt_regs *regs, unsigned long error_code, |
| 241 | unsigned long address) |
| 242 | { |
| 243 | struct task_struct *tsk = current; |
| 244 | struct mm_struct *mm = tsk->mm; |
| 245 | |
| 246 | up_read(&mm->mmap_sem); |
| 247 | /* |
| 248 | * Send a sigbus, regardless of whether we were in kernel |
| 249 | * or user mode. |
| 250 | */ |
| 251 | tsk->thread.prot_addr = address; |
| 252 | tsk->thread.trap_no = error_code; |
| 253 | force_sig(SIGBUS, tsk); |
| 254 | |
| 255 | /* Kernel mode? Handle exceptions or die */ |
| 256 | if (!(regs->psw.mask & PSW_MASK_PSTATE)) |
| 257 | do_no_context(regs, error_code, address); |
| 258 | } |
| 259 | |
Gerald Schaefer | c1821c2 | 2007-02-05 21:18:17 +0100 | [diff] [blame] | 260 | #ifdef CONFIG_S390_EXEC_PROTECT |
| 261 | extern long sys_sigreturn(struct pt_regs *regs); |
| 262 | extern long sys_rt_sigreturn(struct pt_regs *regs); |
| 263 | extern long sys32_sigreturn(struct pt_regs *regs); |
| 264 | extern long sys32_rt_sigreturn(struct pt_regs *regs); |
| 265 | |
Gerald Schaefer | c1821c2 | 2007-02-05 21:18:17 +0100 | [diff] [blame] | 266 | static int signal_return(struct mm_struct *mm, struct pt_regs *regs, |
| 267 | unsigned long address, unsigned long error_code) |
| 268 | { |
Martin Schwidefsky | be5ec36 | 2007-04-27 16:01:44 +0200 | [diff] [blame^] | 269 | u16 instruction; |
| 270 | int rc, compat; |
Gerald Schaefer | c1821c2 | 2007-02-05 21:18:17 +0100 | [diff] [blame] | 271 | |
Martin Schwidefsky | be5ec36 | 2007-04-27 16:01:44 +0200 | [diff] [blame^] | 272 | pagefault_disable(); |
| 273 | rc = __get_user(instruction, (u16 __user *) regs->psw.addr); |
| 274 | pagefault_enable(); |
| 275 | if (rc) |
| 276 | return -EFAULT; |
Gerald Schaefer | c1821c2 | 2007-02-05 21:18:17 +0100 | [diff] [blame] | 277 | |
Martin Schwidefsky | be5ec36 | 2007-04-27 16:01:44 +0200 | [diff] [blame^] | 278 | up_read(&mm->mmap_sem); |
| 279 | clear_tsk_thread_flag(current, TIF_SINGLE_STEP); |
| 280 | #ifdef CONFIG_COMPAT |
| 281 | compat = test_tsk_thread_flag(current, TIF_31BIT); |
| 282 | if (compat && instruction == 0x0a77) |
| 283 | sys32_sigreturn(regs); |
| 284 | else if (compat && instruction == 0x0aad) |
| 285 | sys32_rt_sigreturn(regs); |
| 286 | else |
| 287 | #endif |
| 288 | if (instruction == 0x0a77) |
| 289 | sys_sigreturn(regs); |
| 290 | else if (instruction == 0x0aad) |
| 291 | sys_rt_sigreturn(regs); |
Gerald Schaefer | c1821c2 | 2007-02-05 21:18:17 +0100 | [diff] [blame] | 292 | else { |
Gerald Schaefer | c1821c2 | 2007-02-05 21:18:17 +0100 | [diff] [blame] | 293 | current->thread.prot_addr = address; |
| 294 | current->thread.trap_no = error_code; |
| 295 | do_sigsegv(regs, error_code, SEGV_MAPERR, address); |
| 296 | } |
| 297 | return 0; |
Gerald Schaefer | c1821c2 | 2007-02-05 21:18:17 +0100 | [diff] [blame] | 298 | } |
| 299 | #endif /* CONFIG_S390_EXEC_PROTECT */ |
| 300 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 301 | /* |
| 302 | * This routine handles page faults. It determines the address, |
| 303 | * and the problem, and then passes it off to one of the appropriate |
| 304 | * routines. |
| 305 | * |
| 306 | * error_code: |
| 307 | * 04 Protection -> Write-Protection (suprression) |
| 308 | * 10 Segment translation -> Not present (nullification) |
| 309 | * 11 Page translation -> Not present (nullification) |
| 310 | * 3b Region third trans. -> Not present (nullification) |
| 311 | */ |
Gerald Schaefer | 482b05d | 2007-03-05 23:35:54 +0100 | [diff] [blame] | 312 | static inline void |
Martin Schwidefsky | 10c1031 | 2007-04-27 16:01:43 +0200 | [diff] [blame] | 313 | do_exception(struct pt_regs *regs, unsigned long error_code, int write) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 314 | { |
Martin Schwidefsky | 10c1031 | 2007-04-27 16:01:43 +0200 | [diff] [blame] | 315 | struct task_struct *tsk; |
| 316 | struct mm_struct *mm; |
| 317 | struct vm_area_struct *vma; |
| 318 | unsigned long address; |
Gerald Schaefer | 482b05d | 2007-03-05 23:35:54 +0100 | [diff] [blame] | 319 | int space; |
Martin Schwidefsky | 10c1031 | 2007-04-27 16:01:43 +0200 | [diff] [blame] | 320 | int si_code; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 321 | |
Martin Schwidefsky | 10c1031 | 2007-04-27 16:01:43 +0200 | [diff] [blame] | 322 | if (notify_page_fault(regs, error_code) == NOTIFY_STOP) |
Michael Grundy | 4ba069b | 2006-09-20 15:58:39 +0200 | [diff] [blame] | 323 | return; |
| 324 | |
Martin Schwidefsky | 10c1031 | 2007-04-27 16:01:43 +0200 | [diff] [blame] | 325 | tsk = current; |
| 326 | mm = tsk->mm; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 327 | |
Martin Schwidefsky | 10c1031 | 2007-04-27 16:01:43 +0200 | [diff] [blame] | 328 | /* get the failing address and the affected space */ |
| 329 | address = S390_lowcore.trans_exc_code & __FAIL_ADDR_MASK; |
Gerald Schaefer | 482b05d | 2007-03-05 23:35:54 +0100 | [diff] [blame] | 330 | space = check_space(tsk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 331 | |
| 332 | /* |
| 333 | * Verify that the fault happened in user space, that |
| 334 | * we are not in an interrupt and that there is a |
| 335 | * user context. |
| 336 | */ |
Gerald Schaefer | 482b05d | 2007-03-05 23:35:54 +0100 | [diff] [blame] | 337 | if (unlikely(space == 0 || in_atomic() || !mm)) |
| 338 | goto no_context; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 339 | |
| 340 | /* |
| 341 | * When we get here, the fault happened in the current |
| 342 | * task's user address space, so we can switch on the |
| 343 | * interrupts again and then search the VMAs |
| 344 | */ |
| 345 | local_irq_enable(); |
| 346 | |
Martin Schwidefsky | 10c1031 | 2007-04-27 16:01:43 +0200 | [diff] [blame] | 347 | down_read(&mm->mmap_sem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 348 | |
Gerald Schaefer | 482b05d | 2007-03-05 23:35:54 +0100 | [diff] [blame] | 349 | si_code = SEGV_MAPERR; |
| 350 | vma = find_vma(mm, address); |
| 351 | if (!vma) |
| 352 | goto bad_area; |
Gerald Schaefer | c1821c2 | 2007-02-05 21:18:17 +0100 | [diff] [blame] | 353 | |
| 354 | #ifdef CONFIG_S390_EXEC_PROTECT |
Gerald Schaefer | 482b05d | 2007-03-05 23:35:54 +0100 | [diff] [blame] | 355 | if (unlikely((space == 2) && !(vma->vm_flags & VM_EXEC))) |
Gerald Schaefer | c1821c2 | 2007-02-05 21:18:17 +0100 | [diff] [blame] | 356 | if (!signal_return(mm, regs, address, error_code)) |
| 357 | /* |
| 358 | * signal_return() has done an up_read(&mm->mmap_sem) |
| 359 | * if it returns 0. |
| 360 | */ |
| 361 | return; |
| 362 | #endif |
| 363 | |
Martin Schwidefsky | 10c1031 | 2007-04-27 16:01:43 +0200 | [diff] [blame] | 364 | if (vma->vm_start <= address) |
| 365 | goto good_area; |
| 366 | if (!(vma->vm_flags & VM_GROWSDOWN)) |
| 367 | goto bad_area; |
| 368 | if (expand_stack(vma, address)) |
| 369 | goto bad_area; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 370 | /* |
| 371 | * Ok, we have a good vm_area for this memory access, so |
| 372 | * we can handle it.. |
| 373 | */ |
| 374 | good_area: |
| 375 | si_code = SEGV_ACCERR; |
Martin Schwidefsky | 10c1031 | 2007-04-27 16:01:43 +0200 | [diff] [blame] | 376 | if (!write) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 377 | /* page not present, check vm flags */ |
| 378 | if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))) |
| 379 | goto bad_area; |
| 380 | } else { |
| 381 | if (!(vma->vm_flags & VM_WRITE)) |
| 382 | goto bad_area; |
| 383 | } |
| 384 | |
| 385 | survive: |
| 386 | /* |
| 387 | * If for any reason at all we couldn't handle the fault, |
| 388 | * make sure we exit gracefully rather than endlessly redo |
| 389 | * the fault. |
| 390 | */ |
Martin Schwidefsky | 10c1031 | 2007-04-27 16:01:43 +0200 | [diff] [blame] | 391 | switch (handle_mm_fault(mm, vma, address, write)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 392 | case VM_FAULT_MINOR: |
| 393 | tsk->min_flt++; |
| 394 | break; |
| 395 | case VM_FAULT_MAJOR: |
| 396 | tsk->maj_flt++; |
| 397 | break; |
| 398 | case VM_FAULT_SIGBUS: |
Martin Schwidefsky | 10c1031 | 2007-04-27 16:01:43 +0200 | [diff] [blame] | 399 | do_sigbus(regs, error_code, address); |
| 400 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 401 | case VM_FAULT_OOM: |
Martin Schwidefsky | 10c1031 | 2007-04-27 16:01:43 +0200 | [diff] [blame] | 402 | if (do_out_of_memory(regs, error_code, address)) |
| 403 | goto survive; |
| 404 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 405 | default: |
| 406 | BUG(); |
| 407 | } |
| 408 | |
| 409 | up_read(&mm->mmap_sem); |
| 410 | /* |
| 411 | * The instruction that caused the program check will |
| 412 | * be repeated. Don't signal single step via SIGTRAP. |
| 413 | */ |
Gerald Schaefer | 482b05d | 2007-03-05 23:35:54 +0100 | [diff] [blame] | 414 | clear_tsk_thread_flag(tsk, TIF_SINGLE_STEP); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 415 | return; |
| 416 | |
| 417 | /* |
| 418 | * Something tried to access memory that isn't in our memory map.. |
| 419 | * Fix it, but check if it's kernel or user first.. |
| 420 | */ |
| 421 | bad_area: |
Martin Schwidefsky | 10c1031 | 2007-04-27 16:01:43 +0200 | [diff] [blame] | 422 | up_read(&mm->mmap_sem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 423 | |
Martin Schwidefsky | 10c1031 | 2007-04-27 16:01:43 +0200 | [diff] [blame] | 424 | /* User mode accesses just cause a SIGSEGV */ |
| 425 | if (regs->psw.mask & PSW_MASK_PSTATE) { |
| 426 | tsk->thread.prot_addr = address; |
| 427 | tsk->thread.trap_no = error_code; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 428 | do_sigsegv(regs, error_code, si_code, address); |
Martin Schwidefsky | 10c1031 | 2007-04-27 16:01:43 +0200 | [diff] [blame] | 429 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 430 | } |
| 431 | |
| 432 | no_context: |
Martin Schwidefsky | 10c1031 | 2007-04-27 16:01:43 +0200 | [diff] [blame] | 433 | do_no_context(regs, error_code, address); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 434 | } |
| 435 | |
Gerald Schaefer | 482b05d | 2007-03-05 23:35:54 +0100 | [diff] [blame] | 436 | void __kprobes do_protection_exception(struct pt_regs *regs, |
| 437 | unsigned long error_code) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 438 | { |
Martin Schwidefsky | 10c1031 | 2007-04-27 16:01:43 +0200 | [diff] [blame] | 439 | /* Protection exception is supressing, decrement psw address. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 440 | regs->psw.addr -= (error_code >> 16); |
Martin Schwidefsky | 10c1031 | 2007-04-27 16:01:43 +0200 | [diff] [blame] | 441 | /* |
| 442 | * Check for low-address protection. This needs to be treated |
| 443 | * as a special case because the translation exception code |
| 444 | * field is not guaranteed to contain valid data in this case. |
| 445 | */ |
| 446 | if (unlikely(!(S390_lowcore.trans_exc_code & 4))) { |
| 447 | do_low_address(regs, error_code); |
| 448 | return; |
| 449 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 450 | do_exception(regs, 4, 1); |
| 451 | } |
| 452 | |
Gerald Schaefer | 482b05d | 2007-03-05 23:35:54 +0100 | [diff] [blame] | 453 | void __kprobes do_dat_exception(struct pt_regs *regs, unsigned long error_code) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 454 | { |
| 455 | do_exception(regs, error_code & 0xff, 0); |
| 456 | } |
| 457 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 458 | #ifdef CONFIG_PFAULT |
| 459 | /* |
| 460 | * 'pfault' pseudo page faults routines. |
| 461 | */ |
Heiko Carstens | 29b08d2 | 2006-12-04 15:40:40 +0100 | [diff] [blame] | 462 | static ext_int_info_t ext_int_pfault; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 463 | static int pfault_disable = 0; |
| 464 | |
| 465 | static int __init nopfault(char *str) |
| 466 | { |
| 467 | pfault_disable = 1; |
| 468 | return 1; |
| 469 | } |
| 470 | |
| 471 | __setup("nopfault", nopfault); |
| 472 | |
| 473 | typedef struct { |
| 474 | __u16 refdiagc; |
| 475 | __u16 reffcode; |
| 476 | __u16 refdwlen; |
| 477 | __u16 refversn; |
| 478 | __u64 refgaddr; |
| 479 | __u64 refselmk; |
| 480 | __u64 refcmpmk; |
| 481 | __u64 reserved; |
| 482 | } __attribute__ ((packed)) pfault_refbk_t; |
| 483 | |
| 484 | int pfault_init(void) |
| 485 | { |
| 486 | pfault_refbk_t refbk = |
| 487 | { 0x258, 0, 5, 2, __LC_CURRENT, 1ULL << 48, 1ULL << 48, |
| 488 | __PF_RES_FIELD }; |
| 489 | int rc; |
| 490 | |
Heiko Carstens | 29b08d2 | 2006-12-04 15:40:40 +0100 | [diff] [blame] | 491 | if (!MACHINE_IS_VM || pfault_disable) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 492 | return -1; |
Martin Schwidefsky | 94c12cc | 2006-09-28 16:56:43 +0200 | [diff] [blame] | 493 | asm volatile( |
| 494 | " diag %1,%0,0x258\n" |
| 495 | "0: j 2f\n" |
| 496 | "1: la %0,8\n" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 497 | "2:\n" |
Martin Schwidefsky | 94c12cc | 2006-09-28 16:56:43 +0200 | [diff] [blame] | 498 | EX_TABLE(0b,1b) |
| 499 | : "=d" (rc) : "a" (&refbk), "m" (refbk) : "cc"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 500 | __ctl_set_bit(0, 9); |
| 501 | return rc; |
| 502 | } |
| 503 | |
| 504 | void pfault_fini(void) |
| 505 | { |
| 506 | pfault_refbk_t refbk = |
| 507 | { 0x258, 1, 5, 2, 0ULL, 0ULL, 0ULL, 0ULL }; |
| 508 | |
Heiko Carstens | 29b08d2 | 2006-12-04 15:40:40 +0100 | [diff] [blame] | 509 | if (!MACHINE_IS_VM || pfault_disable) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 510 | return; |
| 511 | __ctl_clear_bit(0,9); |
Martin Schwidefsky | 94c12cc | 2006-09-28 16:56:43 +0200 | [diff] [blame] | 512 | asm volatile( |
| 513 | " diag %0,0,0x258\n" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 514 | "0:\n" |
Martin Schwidefsky | 94c12cc | 2006-09-28 16:56:43 +0200 | [diff] [blame] | 515 | EX_TABLE(0b,0b) |
| 516 | : : "a" (&refbk), "m" (refbk) : "cc"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 517 | } |
| 518 | |
Heiko Carstens | 2b67fc4 | 2007-02-05 21:16:47 +0100 | [diff] [blame] | 519 | static void pfault_interrupt(__u16 error_code) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 520 | { |
| 521 | struct task_struct *tsk; |
| 522 | __u16 subcode; |
| 523 | |
| 524 | /* |
| 525 | * Get the external interruption subcode & pfault |
| 526 | * initial/completion signal bit. VM stores this |
| 527 | * in the 'cpu address' field associated with the |
| 528 | * external interrupt. |
| 529 | */ |
| 530 | subcode = S390_lowcore.cpu_addr; |
| 531 | if ((subcode & 0xff00) != __SUBCODE_MASK) |
| 532 | return; |
| 533 | |
| 534 | /* |
| 535 | * Get the token (= address of the task structure of the affected task). |
| 536 | */ |
| 537 | tsk = *(struct task_struct **) __LC_PFAULT_INTPARM; |
| 538 | |
| 539 | if (subcode & 0x0080) { |
| 540 | /* signal bit is set -> a page has been swapped in by VM */ |
| 541 | if (xchg(&tsk->thread.pfault_wait, -1) != 0) { |
| 542 | /* Initial interrupt was faster than the completion |
| 543 | * interrupt. pfault_wait is valid. Set pfault_wait |
| 544 | * back to zero and wake up the process. This can |
| 545 | * safely be done because the task is still sleeping |
Martin Schwidefsky | b6d0944 | 2005-09-03 15:58:02 -0700 | [diff] [blame] | 546 | * and can't produce new pfaults. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 547 | tsk->thread.pfault_wait = 0; |
| 548 | wake_up_process(tsk); |
Martin Schwidefsky | b6d0944 | 2005-09-03 15:58:02 -0700 | [diff] [blame] | 549 | put_task_struct(tsk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 550 | } |
| 551 | } else { |
| 552 | /* signal bit not set -> a real page is missing. */ |
Martin Schwidefsky | b6d0944 | 2005-09-03 15:58:02 -0700 | [diff] [blame] | 553 | get_task_struct(tsk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 554 | set_task_state(tsk, TASK_UNINTERRUPTIBLE); |
| 555 | if (xchg(&tsk->thread.pfault_wait, 1) != 0) { |
| 556 | /* Completion interrupt was faster than the initial |
| 557 | * interrupt (swapped in a -1 for pfault_wait). Set |
| 558 | * pfault_wait back to zero and exit. This can be |
| 559 | * done safely because tsk is running in kernel |
| 560 | * mode and can't produce new pfaults. */ |
| 561 | tsk->thread.pfault_wait = 0; |
| 562 | set_task_state(tsk, TASK_RUNNING); |
Martin Schwidefsky | b6d0944 | 2005-09-03 15:58:02 -0700 | [diff] [blame] | 563 | put_task_struct(tsk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 564 | } else |
| 565 | set_tsk_need_resched(tsk); |
| 566 | } |
| 567 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 568 | |
Heiko Carstens | 29b08d2 | 2006-12-04 15:40:40 +0100 | [diff] [blame] | 569 | void __init pfault_irq_init(void) |
| 570 | { |
| 571 | if (!MACHINE_IS_VM) |
| 572 | return; |
| 573 | |
| 574 | /* |
| 575 | * Try to get pfault pseudo page faults going. |
| 576 | */ |
| 577 | if (register_early_external_interrupt(0x2603, pfault_interrupt, |
| 578 | &ext_int_pfault) != 0) |
| 579 | panic("Couldn't request external interrupt 0x2603"); |
| 580 | |
| 581 | if (pfault_init() == 0) |
| 582 | return; |
| 583 | |
| 584 | /* Tough luck, no pfault. */ |
| 585 | pfault_disable = 1; |
| 586 | unregister_early_external_interrupt(0x2603, pfault_interrupt, |
| 587 | &ext_int_pfault); |
| 588 | } |
| 589 | #endif |