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TOMOYO Linux Cross Reference
Linux/arch/arm64/kernel/traps.c

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  1 /*
  2  * Based on arch/arm/kernel/traps.c
  3  *
  4  * Copyright (C) 1995-2009 Russell King
  5  * Copyright (C) 2012 ARM Ltd.
  6  *
  7  * This program is free software; you can redistribute it and/or modify
  8  * it under the terms of the GNU General Public License version 2 as
  9  * published by the Free Software Foundation.
 10  *
 11  * This program is distributed in the hope that it will be useful,
 12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 14  * GNU General Public License for more details.
 15  *
 16  * You should have received a copy of the GNU General Public License
 17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 18  */
 19 
 20 #include <linux/signal.h>
 21 #include <linux/personality.h>
 22 #include <linux/kallsyms.h>
 23 #include <linux/spinlock.h>
 24 #include <linux/uaccess.h>
 25 #include <linux/hardirq.h>
 26 #include <linux/kdebug.h>
 27 #include <linux/module.h>
 28 #include <linux/kexec.h>
 29 #include <linux/delay.h>
 30 #include <linux/init.h>
 31 #include <linux/sched.h>
 32 #include <linux/syscalls.h>
 33 
 34 #include <asm/atomic.h>
 35 #include <asm/debug-monitors.h>
 36 #include <asm/esr.h>
 37 #include <asm/traps.h>
 38 #include <asm/stacktrace.h>
 39 #include <asm/exception.h>
 40 #include <asm/system_misc.h>
 41 
 42 static const char *handler[]= {
 43         "Synchronous Abort",
 44         "IRQ",
 45         "FIQ",
 46         "Error"
 47 };
 48 
 49 int show_unhandled_signals = 1;
 50 
 51 /*
 52  * Dump out the contents of some memory nicely...
 53  */
 54 static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
 55                      unsigned long top)
 56 {
 57         unsigned long first;
 58         mm_segment_t fs;
 59         int i;
 60 
 61         /*
 62          * We need to switch to kernel mode so that we can use __get_user
 63          * to safely read from kernel space.  Note that we now dump the
 64          * code first, just in case the backtrace kills us.
 65          */
 66         fs = get_fs();
 67         set_fs(KERNEL_DS);
 68 
 69         printk("%s%s(0x%016lx to 0x%016lx)\n", lvl, str, bottom, top);
 70 
 71         for (first = bottom & ~31; first < top; first += 32) {
 72                 unsigned long p;
 73                 char str[sizeof(" 12345678") * 8 + 1];
 74 
 75                 memset(str, ' ', sizeof(str));
 76                 str[sizeof(str) - 1] = '\0';
 77 
 78                 for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
 79                         if (p >= bottom && p < top) {
 80                                 unsigned int val;
 81                                 if (__get_user(val, (unsigned int *)p) == 0)
 82                                         sprintf(str + i * 9, " %08x", val);
 83                                 else
 84                                         sprintf(str + i * 9, " ????????");
 85                         }
 86                 }
 87                 printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
 88         }
 89 
 90         set_fs(fs);
 91 }
 92 
 93 static void dump_backtrace_entry(unsigned long where, unsigned long stack)
 94 {
 95         print_ip_sym(where);
 96         if (in_exception_text(where))
 97                 dump_mem("", "Exception stack", stack,
 98                          stack + sizeof(struct pt_regs));
 99 }
100 
101 static void dump_instr(const char *lvl, struct pt_regs *regs)
102 {
103         unsigned long addr = instruction_pointer(regs);
104         mm_segment_t fs;
105         char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
106         int i;
107 
108         /*
109          * We need to switch to kernel mode so that we can use __get_user
110          * to safely read from kernel space.  Note that we now dump the
111          * code first, just in case the backtrace kills us.
112          */
113         fs = get_fs();
114         set_fs(KERNEL_DS);
115 
116         for (i = -4; i < 1; i++) {
117                 unsigned int val, bad;
118 
119                 bad = __get_user(val, &((u32 *)addr)[i]);
120 
121                 if (!bad)
122                         p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val);
123                 else {
124                         p += sprintf(p, "bad PC value");
125                         break;
126                 }
127         }
128         printk("%sCode: %s\n", lvl, str);
129 
130         set_fs(fs);
131 }
132 
133 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
134 {
135         struct stackframe frame;
136 
137         pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk);
138 
139         if (!tsk)
140                 tsk = current;
141 
142         if (regs) {
143                 frame.fp = regs->regs[29];
144                 frame.sp = regs->sp;
145                 frame.pc = regs->pc;
146         } else if (tsk == current) {
147                 frame.fp = (unsigned long)__builtin_frame_address(0);
148                 frame.sp = current_stack_pointer;
149                 frame.pc = (unsigned long)dump_backtrace;
150         } else {
151                 /*
152                  * task blocked in __switch_to
153                  */
154                 frame.fp = thread_saved_fp(tsk);
155                 frame.sp = thread_saved_sp(tsk);
156                 frame.pc = thread_saved_pc(tsk);
157         }
158 
159         pr_emerg("Call trace:\n");
160         while (1) {
161                 unsigned long where = frame.pc;
162                 int ret;
163 
164                 ret = unwind_frame(&frame);
165                 if (ret < 0)
166                         break;
167                 dump_backtrace_entry(where, frame.sp);
168         }
169 }
170 
171 void show_stack(struct task_struct *tsk, unsigned long *sp)
172 {
173         dump_backtrace(NULL, tsk);
174         barrier();
175 }
176 
177 #ifdef CONFIG_PREEMPT
178 #define S_PREEMPT " PREEMPT"
179 #else
180 #define S_PREEMPT ""
181 #endif
182 #ifdef CONFIG_SMP
183 #define S_SMP " SMP"
184 #else
185 #define S_SMP ""
186 #endif
187 
188 static int __die(const char *str, int err, struct thread_info *thread,
189                  struct pt_regs *regs)
190 {
191         struct task_struct *tsk = thread->task;
192         static int die_counter;
193         int ret;
194 
195         pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n",
196                  str, err, ++die_counter);
197 
198         /* trap and error numbers are mostly meaningless on ARM */
199         ret = notify_die(DIE_OOPS, str, regs, err, 0, SIGSEGV);
200         if (ret == NOTIFY_STOP)
201                 return ret;
202 
203         print_modules();
204         __show_regs(regs);
205         pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
206                  TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), thread + 1);
207 
208         if (!user_mode(regs) || in_interrupt()) {
209                 dump_mem(KERN_EMERG, "Stack: ", regs->sp,
210                          THREAD_SIZE + (unsigned long)task_stack_page(tsk));
211                 dump_backtrace(regs, tsk);
212                 dump_instr(KERN_EMERG, regs);
213         }
214 
215         return ret;
216 }
217 
218 static DEFINE_RAW_SPINLOCK(die_lock);
219 
220 /*
221  * This function is protected against re-entrancy.
222  */
223 void die(const char *str, struct pt_regs *regs, int err)
224 {
225         struct thread_info *thread = current_thread_info();
226         int ret;
227 
228         oops_enter();
229 
230         raw_spin_lock_irq(&die_lock);
231         console_verbose();
232         bust_spinlocks(1);
233         ret = __die(str, err, thread, regs);
234 
235         if (regs && kexec_should_crash(thread->task))
236                 crash_kexec(regs);
237 
238         bust_spinlocks(0);
239         add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
240         raw_spin_unlock_irq(&die_lock);
241         oops_exit();
242 
243         if (in_interrupt())
244                 panic("Fatal exception in interrupt");
245         if (panic_on_oops)
246                 panic("Fatal exception");
247         if (ret != NOTIFY_STOP)
248                 do_exit(SIGSEGV);
249 }
250 
251 void arm64_notify_die(const char *str, struct pt_regs *regs,
252                       struct siginfo *info, int err)
253 {
254         if (user_mode(regs)) {
255                 current->thread.fault_address = 0;
256                 current->thread.fault_code = err;
257                 force_sig_info(info->si_signo, info, current);
258         } else {
259                 die(str, regs, err);
260         }
261 }
262 
263 static LIST_HEAD(undef_hook);
264 static DEFINE_RAW_SPINLOCK(undef_lock);
265 
266 void register_undef_hook(struct undef_hook *hook)
267 {
268         unsigned long flags;
269 
270         raw_spin_lock_irqsave(&undef_lock, flags);
271         list_add(&hook->node, &undef_hook);
272         raw_spin_unlock_irqrestore(&undef_lock, flags);
273 }
274 
275 void unregister_undef_hook(struct undef_hook *hook)
276 {
277         unsigned long flags;
278 
279         raw_spin_lock_irqsave(&undef_lock, flags);
280         list_del(&hook->node);
281         raw_spin_unlock_irqrestore(&undef_lock, flags);
282 }
283 
284 static int call_undef_hook(struct pt_regs *regs)
285 {
286         struct undef_hook *hook;
287         unsigned long flags;
288         u32 instr;
289         int (*fn)(struct pt_regs *regs, u32 instr) = NULL;
290         void __user *pc = (void __user *)instruction_pointer(regs);
291 
292         if (!user_mode(regs))
293                 return 1;
294 
295         if (compat_thumb_mode(regs)) {
296                 /* 16-bit Thumb instruction */
297                 if (get_user(instr, (u16 __user *)pc))
298                         goto exit;
299                 instr = le16_to_cpu(instr);
300                 if (aarch32_insn_is_wide(instr)) {
301                         u32 instr2;
302 
303                         if (get_user(instr2, (u16 __user *)(pc + 2)))
304                                 goto exit;
305                         instr2 = le16_to_cpu(instr2);
306                         instr = (instr << 16) | instr2;
307                 }
308         } else {
309                 /* 32-bit ARM instruction */
310                 if (get_user(instr, (u32 __user *)pc))
311                         goto exit;
312                 instr = le32_to_cpu(instr);
313         }
314 
315         raw_spin_lock_irqsave(&undef_lock, flags);
316         list_for_each_entry(hook, &undef_hook, node)
317                 if ((instr & hook->instr_mask) == hook->instr_val &&
318                         (regs->pstate & hook->pstate_mask) == hook->pstate_val)
319                         fn = hook->fn;
320 
321         raw_spin_unlock_irqrestore(&undef_lock, flags);
322 exit:
323         return fn ? fn(regs, instr) : 1;
324 }
325 
326 asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
327 {
328         siginfo_t info;
329         void __user *pc = (void __user *)instruction_pointer(regs);
330 
331         /* check for AArch32 breakpoint instructions */
332         if (!aarch32_break_handler(regs))
333                 return;
334 
335         if (call_undef_hook(regs) == 0)
336                 return;
337 
338         if (unhandled_signal(current, SIGILL) && show_unhandled_signals_ratelimited()) {
339                 pr_info("%s[%d]: undefined instruction: pc=%p\n",
340                         current->comm, task_pid_nr(current), pc);
341                 dump_instr(KERN_INFO, regs);
342         }
343 
344         info.si_signo = SIGILL;
345         info.si_errno = 0;
346         info.si_code  = ILL_ILLOPC;
347         info.si_addr  = pc;
348 
349         arm64_notify_die("Oops - undefined instruction", regs, &info, 0);
350 }
351 
352 long compat_arm_syscall(struct pt_regs *regs);
353 
354 asmlinkage long do_ni_syscall(struct pt_regs *regs)
355 {
356 #ifdef CONFIG_COMPAT
357         long ret;
358         if (is_compat_task()) {
359                 ret = compat_arm_syscall(regs);
360                 if (ret != -ENOSYS)
361                         return ret;
362         }
363 #endif
364 
365         if (show_unhandled_signals_ratelimited()) {
366                 pr_info("%s[%d]: syscall %d\n", current->comm,
367                         task_pid_nr(current), (int)regs->syscallno);
368                 dump_instr("", regs);
369                 if (user_mode(regs))
370                         __show_regs(regs);
371         }
372 
373         return sys_ni_syscall();
374 }
375 
376 static const char *esr_class_str[] = {
377         [0 ... ESR_ELx_EC_MAX]          = "UNRECOGNIZED EC",
378         [ESR_ELx_EC_UNKNOWN]            = "Unknown/Uncategorized",
379         [ESR_ELx_EC_WFx]                = "WFI/WFE",
380         [ESR_ELx_EC_CP15_32]            = "CP15 MCR/MRC",
381         [ESR_ELx_EC_CP15_64]            = "CP15 MCRR/MRRC",
382         [ESR_ELx_EC_CP14_MR]            = "CP14 MCR/MRC",
383         [ESR_ELx_EC_CP14_LS]            = "CP14 LDC/STC",
384         [ESR_ELx_EC_FP_ASIMD]           = "ASIMD",
385         [ESR_ELx_EC_CP10_ID]            = "CP10 MRC/VMRS",
386         [ESR_ELx_EC_CP14_64]            = "CP14 MCRR/MRRC",
387         [ESR_ELx_EC_ILL]                = "PSTATE.IL",
388         [ESR_ELx_EC_SVC32]              = "SVC (AArch32)",
389         [ESR_ELx_EC_HVC32]              = "HVC (AArch32)",
390         [ESR_ELx_EC_SMC32]              = "SMC (AArch32)",
391         [ESR_ELx_EC_SVC64]              = "SVC (AArch64)",
392         [ESR_ELx_EC_HVC64]              = "HVC (AArch64)",
393         [ESR_ELx_EC_SMC64]              = "SMC (AArch64)",
394         [ESR_ELx_EC_SYS64]              = "MSR/MRS (AArch64)",
395         [ESR_ELx_EC_IMP_DEF]            = "EL3 IMP DEF",
396         [ESR_ELx_EC_IABT_LOW]           = "IABT (lower EL)",
397         [ESR_ELx_EC_IABT_CUR]           = "IABT (current EL)",
398         [ESR_ELx_EC_PC_ALIGN]           = "PC Alignment",
399         [ESR_ELx_EC_DABT_LOW]           = "DABT (lower EL)",
400         [ESR_ELx_EC_DABT_CUR]           = "DABT (current EL)",
401         [ESR_ELx_EC_SP_ALIGN]           = "SP Alignment",
402         [ESR_ELx_EC_FP_EXC32]           = "FP (AArch32)",
403         [ESR_ELx_EC_FP_EXC64]           = "FP (AArch64)",
404         [ESR_ELx_EC_SERROR]             = "SError",
405         [ESR_ELx_EC_BREAKPT_LOW]        = "Breakpoint (lower EL)",
406         [ESR_ELx_EC_BREAKPT_CUR]        = "Breakpoint (current EL)",
407         [ESR_ELx_EC_SOFTSTP_LOW]        = "Software Step (lower EL)",
408         [ESR_ELx_EC_SOFTSTP_CUR]        = "Software Step (current EL)",
409         [ESR_ELx_EC_WATCHPT_LOW]        = "Watchpoint (lower EL)",
410         [ESR_ELx_EC_WATCHPT_CUR]        = "Watchpoint (current EL)",
411         [ESR_ELx_EC_BKPT32]             = "BKPT (AArch32)",
412         [ESR_ELx_EC_VECTOR32]           = "Vector catch (AArch32)",
413         [ESR_ELx_EC_BRK64]              = "BRK (AArch64)",
414 };
415 
416 const char *esr_get_class_string(u32 esr)
417 {
418         return esr_class_str[esr >> ESR_ELx_EC_SHIFT];
419 }
420 
421 /*
422  * bad_mode handles the impossible case in the exception vector.
423  */
424 asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr)
425 {
426         siginfo_t info;
427         void __user *pc = (void __user *)instruction_pointer(regs);
428         console_verbose();
429 
430         pr_crit("Bad mode in %s handler detected, code 0x%08x -- %s\n",
431                 handler[reason], esr, esr_get_class_string(esr));
432         __show_regs(regs);
433 
434         info.si_signo = SIGILL;
435         info.si_errno = 0;
436         info.si_code  = ILL_ILLOPC;
437         info.si_addr  = pc;
438 
439         arm64_notify_die("Oops - bad mode", regs, &info, 0);
440 }
441 
442 void __pte_error(const char *file, int line, unsigned long val)
443 {
444         pr_crit("%s:%d: bad pte %016lx.\n", file, line, val);
445 }
446 
447 void __pmd_error(const char *file, int line, unsigned long val)
448 {
449         pr_crit("%s:%d: bad pmd %016lx.\n", file, line, val);
450 }
451 
452 void __pud_error(const char *file, int line, unsigned long val)
453 {
454         pr_crit("%s:%d: bad pud %016lx.\n", file, line, val);
455 }
456 
457 void __pgd_error(const char *file, int line, unsigned long val)
458 {
459         pr_crit("%s:%d: bad pgd %016lx.\n", file, line, val);
460 }
461 
462 void __init trap_init(void)
463 {
464         return;
465 }
466 

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