~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/arch/unicore32/mm/fault.c

Version: ~ [ linux-5.2 ] ~ [ linux-5.1.16 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.57 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.132 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.184 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.184 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.69 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.39.4 ] ~ [ linux-2.6.38.8 ] ~ [ linux-2.6.37.6 ] ~ [ linux-2.6.36.4 ] ~ [ linux-2.6.35.14 ] ~ [ linux-2.6.34.15 ] ~ [ linux-2.6.33.20 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  * linux/arch/unicore32/mm/fault.c
  3  *
  4  * Code specific to PKUnity SoC and UniCore ISA
  5  *
  6  * Copyright (C) 2001-2010 GUAN Xue-tao
  7  *
  8  * This program is free software; you can redistribute it and/or modify
  9  * it under the terms of the GNU General Public License version 2 as
 10  * published by the Free Software Foundation.
 11  */
 12 #include <linux/module.h>
 13 #include <linux/signal.h>
 14 #include <linux/mm.h>
 15 #include <linux/hardirq.h>
 16 #include <linux/init.h>
 17 #include <linux/kprobes.h>
 18 #include <linux/uaccess.h>
 19 #include <linux/page-flags.h>
 20 #include <linux/sched.h>
 21 #include <linux/io.h>
 22 
 23 #include <asm/pgtable.h>
 24 #include <asm/tlbflush.h>
 25 
 26 /*
 27  * Fault status register encodings.  We steal bit 31 for our own purposes.
 28  */
 29 #define FSR_LNX_PF              (1 << 31)
 30 
 31 static inline int fsr_fs(unsigned int fsr)
 32 {
 33         /* xyabcde will be abcde+xy */
 34         return (fsr & 31) + ((fsr & (3 << 5)) >> 5);
 35 }
 36 
 37 /*
 38  * This is useful to dump out the page tables associated with
 39  * 'addr' in mm 'mm'.
 40  */
 41 void show_pte(struct mm_struct *mm, unsigned long addr)
 42 {
 43         pgd_t *pgd;
 44 
 45         if (!mm)
 46                 mm = &init_mm;
 47 
 48         printk(KERN_ALERT "pgd = %p\n", mm->pgd);
 49         pgd = pgd_offset(mm, addr);
 50         printk(KERN_ALERT "[%08lx] *pgd=%08lx", addr, pgd_val(*pgd));
 51 
 52         do {
 53                 pmd_t *pmd;
 54                 pte_t *pte;
 55 
 56                 if (pgd_none(*pgd))
 57                         break;
 58 
 59                 if (pgd_bad(*pgd)) {
 60                         printk("(bad)");
 61                         break;
 62                 }
 63 
 64                 pmd = pmd_offset((pud_t *) pgd, addr);
 65                 if (PTRS_PER_PMD != 1)
 66                         printk(", *pmd=%08lx", pmd_val(*pmd));
 67 
 68                 if (pmd_none(*pmd))
 69                         break;
 70 
 71                 if (pmd_bad(*pmd)) {
 72                         printk("(bad)");
 73                         break;
 74                 }
 75 
 76                 /* We must not map this if we have highmem enabled */
 77                 if (PageHighMem(pfn_to_page(pmd_val(*pmd) >> PAGE_SHIFT)))
 78                         break;
 79 
 80                 pte = pte_offset_map(pmd, addr);
 81                 printk(", *pte=%08lx", pte_val(*pte));
 82                 pte_unmap(pte);
 83         } while (0);
 84 
 85         printk("\n");
 86 }
 87 
 88 /*
 89  * Oops.  The kernel tried to access some page that wasn't present.
 90  */
 91 static void __do_kernel_fault(struct mm_struct *mm, unsigned long addr,
 92                 unsigned int fsr, struct pt_regs *regs)
 93 {
 94         /*
 95          * Are we prepared to handle this kernel fault?
 96          */
 97         if (fixup_exception(regs))
 98                 return;
 99 
100         /*
101          * No handler, we'll have to terminate things with extreme prejudice.
102          */
103         bust_spinlocks(1);
104         printk(KERN_ALERT
105                "Unable to handle kernel %s at virtual address %08lx\n",
106                (addr < PAGE_SIZE) ? "NULL pointer dereference" :
107                "paging request", addr);
108 
109         show_pte(mm, addr);
110         die("Oops", regs, fsr);
111         bust_spinlocks(0);
112         do_exit(SIGKILL);
113 }
114 
115 /*
116  * Something tried to access memory that isn't in our memory map..
117  * User mode accesses just cause a SIGSEGV
118  */
119 static void __do_user_fault(struct task_struct *tsk, unsigned long addr,
120                 unsigned int fsr, unsigned int sig, int code,
121                 struct pt_regs *regs)
122 {
123         struct siginfo si;
124 
125         tsk->thread.address = addr;
126         tsk->thread.error_code = fsr;
127         tsk->thread.trap_no = 14;
128         si.si_signo = sig;
129         si.si_errno = 0;
130         si.si_code = code;
131         si.si_addr = (void __user *)addr;
132         force_sig_info(sig, &si, tsk);
133 }
134 
135 void do_bad_area(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
136 {
137         struct task_struct *tsk = current;
138         struct mm_struct *mm = tsk->active_mm;
139 
140         /*
141          * If we are in kernel mode at this point, we
142          * have no context to handle this fault with.
143          */
144         if (user_mode(regs))
145                 __do_user_fault(tsk, addr, fsr, SIGSEGV, SEGV_MAPERR, regs);
146         else
147                 __do_kernel_fault(mm, addr, fsr, regs);
148 }
149 
150 #define VM_FAULT_BADMAP         0x010000
151 #define VM_FAULT_BADACCESS      0x020000
152 
153 /*
154  * Check that the permissions on the VMA allow for the fault which occurred.
155  * If we encountered a write fault, we must have write permission, otherwise
156  * we allow any permission.
157  */
158 static inline bool access_error(unsigned int fsr, struct vm_area_struct *vma)
159 {
160         unsigned int mask = VM_READ | VM_WRITE | VM_EXEC;
161 
162         if (!(fsr ^ 0x12))      /* write? */
163                 mask = VM_WRITE;
164         if (fsr & FSR_LNX_PF)
165                 mask = VM_EXEC;
166 
167         return vma->vm_flags & mask ? false : true;
168 }
169 
170 static int __do_pf(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
171                 unsigned int flags, struct task_struct *tsk)
172 {
173         struct vm_area_struct *vma;
174         int fault;
175 
176         vma = find_vma(mm, addr);
177         fault = VM_FAULT_BADMAP;
178         if (unlikely(!vma))
179                 goto out;
180         if (unlikely(vma->vm_start > addr))
181                 goto check_stack;
182 
183         /*
184          * Ok, we have a good vm_area for this
185          * memory access, so we can handle it.
186          */
187 good_area:
188         if (access_error(fsr, vma)) {
189                 fault = VM_FAULT_BADACCESS;
190                 goto out;
191         }
192 
193         /*
194          * If for any reason at all we couldn't handle the fault, make
195          * sure we exit gracefully rather than endlessly redo the fault.
196          */
197         fault = handle_mm_fault(mm, vma, addr & PAGE_MASK, flags);
198         return fault;
199 
200 check_stack:
201         if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr))
202                 goto good_area;
203 out:
204         return fault;
205 }
206 
207 static int do_pf(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
208 {
209         struct task_struct *tsk;
210         struct mm_struct *mm;
211         int fault, sig, code;
212         unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
213 
214         tsk = current;
215         mm = tsk->mm;
216 
217         /*
218          * If we're in an interrupt or have no user
219          * context, we must not take the fault..
220          */
221         if (faulthandler_disabled() || !mm)
222                 goto no_context;
223 
224         if (user_mode(regs))
225                 flags |= FAULT_FLAG_USER;
226         if (!(fsr ^ 0x12))
227                 flags |= FAULT_FLAG_WRITE;
228 
229         /*
230          * As per x86, we may deadlock here.  However, since the kernel only
231          * validly references user space from well defined areas of the code,
232          * we can bug out early if this is from code which shouldn't.
233          */
234         if (!down_read_trylock(&mm->mmap_sem)) {
235                 if (!user_mode(regs)
236                     && !search_exception_tables(regs->UCreg_pc))
237                         goto no_context;
238 retry:
239                 down_read(&mm->mmap_sem);
240         } else {
241                 /*
242                  * The above down_read_trylock() might have succeeded in
243                  * which case, we'll have missed the might_sleep() from
244                  * down_read()
245                  */
246                 might_sleep();
247 #ifdef CONFIG_DEBUG_VM
248                 if (!user_mode(regs) &&
249                     !search_exception_tables(regs->UCreg_pc))
250                         goto no_context;
251 #endif
252         }
253 
254         fault = __do_pf(mm, addr, fsr, flags, tsk);
255 
256         /* If we need to retry but a fatal signal is pending, handle the
257          * signal first. We do not need to release the mmap_sem because
258          * it would already be released in __lock_page_or_retry in
259          * mm/filemap.c. */
260         if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
261                 return 0;
262 
263         if (!(fault & VM_FAULT_ERROR) && (flags & FAULT_FLAG_ALLOW_RETRY)) {
264                 if (fault & VM_FAULT_MAJOR)
265                         tsk->maj_flt++;
266                 else
267                         tsk->min_flt++;
268                 if (fault & VM_FAULT_RETRY) {
269                         /* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk
270                         * of starvation. */
271                         flags &= ~FAULT_FLAG_ALLOW_RETRY;
272                         goto retry;
273                 }
274         }
275 
276         up_read(&mm->mmap_sem);
277 
278         /*
279          * Handle the "normal" case first - VM_FAULT_MAJOR / VM_FAULT_MINOR
280          */
281         if (likely(!(fault &
282                (VM_FAULT_ERROR | VM_FAULT_BADMAP | VM_FAULT_BADACCESS))))
283                 return 0;
284 
285         /*
286          * If we are in kernel mode at this point, we
287          * have no context to handle this fault with.
288          */
289         if (!user_mode(regs))
290                 goto no_context;
291 
292         if (fault & VM_FAULT_OOM) {
293                 /*
294                  * We ran out of memory, call the OOM killer, and return to
295                  * userspace (which will retry the fault, or kill us if we
296                  * got oom-killed)
297                  */
298                 pagefault_out_of_memory();
299                 return 0;
300         }
301 
302         if (fault & VM_FAULT_SIGBUS) {
303                 /*
304                  * We had some memory, but were unable to
305                  * successfully fix up this page fault.
306                  */
307                 sig = SIGBUS;
308                 code = BUS_ADRERR;
309         } else {
310                 /*
311                  * Something tried to access memory that
312                  * isn't in our memory map..
313                  */
314                 sig = SIGSEGV;
315                 code = fault == VM_FAULT_BADACCESS ? SEGV_ACCERR : SEGV_MAPERR;
316         }
317 
318         __do_user_fault(tsk, addr, fsr, sig, code, regs);
319         return 0;
320 
321 no_context:
322         __do_kernel_fault(mm, addr, fsr, regs);
323         return 0;
324 }
325 
326 /*
327  * First Level Translation Fault Handler
328  *
329  * We enter here because the first level page table doesn't contain
330  * a valid entry for the address.
331  *
332  * If the address is in kernel space (>= TASK_SIZE), then we are
333  * probably faulting in the vmalloc() area.
334  *
335  * If the init_task's first level page tables contains the relevant
336  * entry, we copy the it to this task.  If not, we send the process
337  * a signal, fixup the exception, or oops the kernel.
338  *
339  * NOTE! We MUST NOT take any locks for this case. We may be in an
340  * interrupt or a critical region, and should only copy the information
341  * from the master page table, nothing more.
342  */
343 static int do_ifault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
344 {
345         unsigned int index;
346         pgd_t *pgd, *pgd_k;
347         pmd_t *pmd, *pmd_k;
348 
349         if (addr < TASK_SIZE)
350                 return do_pf(addr, fsr, regs);
351 
352         if (user_mode(regs))
353                 goto bad_area;
354 
355         index = pgd_index(addr);
356 
357         pgd = cpu_get_pgd() + index;
358         pgd_k = init_mm.pgd + index;
359 
360         if (pgd_none(*pgd_k))
361                 goto bad_area;
362 
363         pmd_k = pmd_offset((pud_t *) pgd_k, addr);
364         pmd = pmd_offset((pud_t *) pgd, addr);
365 
366         if (pmd_none(*pmd_k))
367                 goto bad_area;
368 
369         set_pmd(pmd, *pmd_k);
370         flush_pmd_entry(pmd);
371         return 0;
372 
373 bad_area:
374         do_bad_area(addr, fsr, regs);
375         return 0;
376 }
377 
378 /*
379  * This abort handler always returns "fault".
380  */
381 static int do_bad(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
382 {
383         return 1;
384 }
385 
386 static int do_good(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
387 {
388         unsigned int res1, res2;
389 
390         printk("dabt exception but no error!\n");
391 
392         __asm__ __volatile__(
393                         "mff %0,f0\n"
394                         "mff %1,f1\n"
395                         : "=r"(res1), "=r"(res2)
396                         :
397                         : "memory");
398 
399         printk(KERN_EMERG "r0 :%08x  r1 :%08x\n", res1, res2);
400         panic("shut up\n");
401         return 0;
402 }
403 
404 static struct fsr_info {
405         int (*fn) (unsigned long addr, unsigned int fsr, struct pt_regs *regs);
406         int sig;
407         int code;
408         const char *name;
409 } fsr_info[] = {
410         /*
411          * The following are the standard Unicore-I and UniCore-II aborts.
412          */
413         { do_good,      SIGBUS,  0,             "no error"              },
414         { do_bad,       SIGBUS,  BUS_ADRALN,    "alignment exception"   },
415         { do_bad,       SIGBUS,  BUS_OBJERR,    "external exception"    },
416         { do_bad,       SIGBUS,  0,             "burst operation"       },
417         { do_bad,       SIGBUS,  0,             "unknown 00100"         },
418         { do_ifault,    SIGSEGV, SEGV_MAPERR,   "2nd level pt non-exist"},
419         { do_bad,       SIGBUS,  0,             "2nd lvl large pt non-exist" },
420         { do_bad,       SIGBUS,  0,             "invalid pte"           },
421         { do_pf,        SIGSEGV, SEGV_MAPERR,   "page miss"             },
422         { do_bad,       SIGBUS,  0,             "middle page miss"      },
423         { do_bad,       SIGBUS,  0,             "large page miss"       },
424         { do_pf,        SIGSEGV, SEGV_MAPERR,   "super page (section) miss" },
425         { do_bad,       SIGBUS,  0,             "unknown 01100"         },
426         { do_bad,       SIGBUS,  0,             "unknown 01101"         },
427         { do_bad,       SIGBUS,  0,             "unknown 01110"         },
428         { do_bad,       SIGBUS,  0,             "unknown 01111"         },
429         { do_bad,       SIGBUS,  0,             "addr: up 3G or IO"     },
430         { do_pf,        SIGSEGV, SEGV_ACCERR,   "read unreadable addr"  },
431         { do_pf,        SIGSEGV, SEGV_ACCERR,   "write unwriteable addr"},
432         { do_pf,        SIGSEGV, SEGV_ACCERR,   "exec unexecutable addr"},
433         { do_bad,       SIGBUS,  0,             "unknown 10100"         },
434         { do_bad,       SIGBUS,  0,             "unknown 10101"         },
435         { do_bad,       SIGBUS,  0,             "unknown 10110"         },
436         { do_bad,       SIGBUS,  0,             "unknown 10111"         },
437         { do_bad,       SIGBUS,  0,             "unknown 11000"         },
438         { do_bad,       SIGBUS,  0,             "unknown 11001"         },
439         { do_bad,       SIGBUS,  0,             "unknown 11010"         },
440         { do_bad,       SIGBUS,  0,             "unknown 11011"         },
441         { do_bad,       SIGBUS,  0,             "unknown 11100"         },
442         { do_bad,       SIGBUS,  0,             "unknown 11101"         },
443         { do_bad,       SIGBUS,  0,             "unknown 11110"         },
444         { do_bad,       SIGBUS,  0,             "unknown 11111"         }
445 };
446 
447 void __init hook_fault_code(int nr,
448                 int (*fn) (unsigned long, unsigned int, struct pt_regs *),
449                 int sig, int code, const char *name)
450 {
451         if (nr < 0 || nr >= ARRAY_SIZE(fsr_info))
452                 BUG();
453 
454         fsr_info[nr].fn   = fn;
455         fsr_info[nr].sig  = sig;
456         fsr_info[nr].code = code;
457         fsr_info[nr].name = name;
458 }
459 
460 /*
461  * Dispatch a data abort to the relevant handler.
462  */
463 asmlinkage void do_DataAbort(unsigned long addr, unsigned int fsr,
464                         struct pt_regs *regs)
465 {
466         const struct fsr_info *inf = fsr_info + fsr_fs(fsr);
467         struct siginfo info;
468 
469         if (!inf->fn(addr, fsr & ~FSR_LNX_PF, regs))
470                 return;
471 
472         printk(KERN_ALERT "Unhandled fault: %s (0x%03x) at 0x%08lx\n",
473                inf->name, fsr, addr);
474 
475         info.si_signo = inf->sig;
476         info.si_errno = 0;
477         info.si_code = inf->code;
478         info.si_addr = (void __user *)addr;
479         uc32_notify_die("", regs, &info, fsr, 0);
480 }
481 
482 asmlinkage void do_PrefetchAbort(unsigned long addr,
483                         unsigned int ifsr, struct pt_regs *regs)
484 {
485         const struct fsr_info *inf = fsr_info + fsr_fs(ifsr);
486         struct siginfo info;
487 
488         if (!inf->fn(addr, ifsr | FSR_LNX_PF, regs))
489                 return;
490 
491         printk(KERN_ALERT "Unhandled prefetch abort: %s (0x%03x) at 0x%08lx\n",
492                inf->name, ifsr, addr);
493 
494         info.si_signo = inf->sig;
495         info.si_errno = 0;
496         info.si_code = inf->code;
497         info.si_addr = (void __user *)addr;
498         uc32_notify_die("", regs, &info, ifsr, 0);
499 }
500 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp