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

TOMOYO Linux Cross Reference
Linux/arch/ia64/mm/fault.c

Version: ~ [ linux-5.14-rc3 ] ~ [ linux-5.13.5 ] ~ [ linux-5.12.19 ] ~ [ linux-5.11.22 ] ~ [ linux-5.10.53 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.135 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.198 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.240 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.276 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.276 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.18.140 ] ~ [ linux-3.16.85 ] ~ [ linux-3.14.79 ] ~ [ linux-3.12.74 ] ~ [ linux-3.10.108 ] ~ [ 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  * MMU fault handling support.
  3  *
  4  * Copyright (C) 1998-2002 Hewlett-Packard Co
  5  *      David Mosberger-Tang <davidm@hpl.hp.com>
  6  */
  7 #include <linux/sched.h>
  8 #include <linux/kernel.h>
  9 #include <linux/mm.h>
 10 #include <linux/interrupt.h>
 11 #include <linux/kprobes.h>
 12 #include <linux/kdebug.h>
 13 #include <linux/prefetch.h>
 14 
 15 #include <asm/pgtable.h>
 16 #include <asm/processor.h>
 17 #include <asm/uaccess.h>
 18 
 19 extern int die(char *, struct pt_regs *, long);
 20 
 21 #ifdef CONFIG_KPROBES
 22 static inline int notify_page_fault(struct pt_regs *regs, int trap)
 23 {
 24         int ret = 0;
 25 
 26         if (!user_mode(regs)) {
 27                 /* kprobe_running() needs smp_processor_id() */
 28                 preempt_disable();
 29                 if (kprobe_running() && kprobe_fault_handler(regs, trap))
 30                         ret = 1;
 31                 preempt_enable();
 32         }
 33 
 34         return ret;
 35 }
 36 #else
 37 static inline int notify_page_fault(struct pt_regs *regs, int trap)
 38 {
 39         return 0;
 40 }
 41 #endif
 42 
 43 /*
 44  * Return TRUE if ADDRESS points at a page in the kernel's mapped segment
 45  * (inside region 5, on ia64) and that page is present.
 46  */
 47 static int
 48 mapped_kernel_page_is_present (unsigned long address)
 49 {
 50         pgd_t *pgd;
 51         pud_t *pud;
 52         pmd_t *pmd;
 53         pte_t *ptep, pte;
 54 
 55         pgd = pgd_offset_k(address);
 56         if (pgd_none(*pgd) || pgd_bad(*pgd))
 57                 return 0;
 58 
 59         pud = pud_offset(pgd, address);
 60         if (pud_none(*pud) || pud_bad(*pud))
 61                 return 0;
 62 
 63         pmd = pmd_offset(pud, address);
 64         if (pmd_none(*pmd) || pmd_bad(*pmd))
 65                 return 0;
 66 
 67         ptep = pte_offset_kernel(pmd, address);
 68         if (!ptep)
 69                 return 0;
 70 
 71         pte = *ptep;
 72         return pte_present(pte);
 73 }
 74 
 75 #       define VM_READ_BIT      0
 76 #       define VM_WRITE_BIT     1
 77 #       define VM_EXEC_BIT      2
 78 
 79 void __kprobes
 80 ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *regs)
 81 {
 82         int signal = SIGSEGV, code = SEGV_MAPERR;
 83         struct vm_area_struct *vma, *prev_vma;
 84         struct mm_struct *mm = current->mm;
 85         struct siginfo si;
 86         unsigned long mask;
 87         int fault;
 88         unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
 89 
 90         mask = ((((isr >> IA64_ISR_X_BIT) & 1UL) << VM_EXEC_BIT)
 91                 | (((isr >> IA64_ISR_W_BIT) & 1UL) << VM_WRITE_BIT));
 92 
 93         /* mmap_sem is performance critical.... */
 94         prefetchw(&mm->mmap_sem);
 95 
 96         /*
 97          * If we're in an interrupt or have no user context, we must not take the fault..
 98          */
 99         if (in_atomic() || !mm)
100                 goto no_context;
101 
102 #ifdef CONFIG_VIRTUAL_MEM_MAP
103         /*
104          * If fault is in region 5 and we are in the kernel, we may already
105          * have the mmap_sem (pfn_valid macro is called during mmap). There
106          * is no vma for region 5 addr's anyway, so skip getting the semaphore
107          * and go directly to the exception handling code.
108          */
109 
110         if ((REGION_NUMBER(address) == 5) && !user_mode(regs))
111                 goto bad_area_no_up;
112 #endif
113 
114         /*
115          * This is to handle the kprobes on user space access instructions
116          */
117         if (notify_page_fault(regs, TRAP_BRKPT))
118                 return;
119 
120         if (user_mode(regs))
121                 flags |= FAULT_FLAG_USER;
122         if (mask & VM_WRITE)
123                 flags |= FAULT_FLAG_WRITE;
124 retry:
125         down_read(&mm->mmap_sem);
126 
127         vma = find_vma_prev(mm, address, &prev_vma);
128         if (!vma && !prev_vma )
129                 goto bad_area;
130 
131         /*
132          * find_vma_prev() returns vma such that address < vma->vm_end or NULL
133          *
134          * May find no vma, but could be that the last vm area is the
135          * register backing store that needs to expand upwards, in
136          * this case vma will be null, but prev_vma will ne non-null
137          */
138         if (( !vma && prev_vma ) || (address < vma->vm_start) )
139                 goto check_expansion;
140 
141   good_area:
142         code = SEGV_ACCERR;
143 
144         /* OK, we've got a good vm_area for this memory area.  Check the access permissions: */
145 
146 #       if (((1 << VM_READ_BIT) != VM_READ || (1 << VM_WRITE_BIT) != VM_WRITE) \
147             || (1 << VM_EXEC_BIT) != VM_EXEC)
148 #               error File is out of sync with <linux/mm.h>.  Please update.
149 #       endif
150 
151         if (((isr >> IA64_ISR_R_BIT) & 1UL) && (!(vma->vm_flags & (VM_READ | VM_WRITE))))
152                 goto bad_area;
153 
154         if ((vma->vm_flags & mask) != mask)
155                 goto bad_area;
156 
157         /*
158          * If for any reason at all we couldn't handle the fault, make
159          * sure we exit gracefully rather than endlessly redo the
160          * fault.
161          */
162         fault = handle_mm_fault(mm, vma, address, flags);
163 
164         if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
165                 return;
166 
167         if (unlikely(fault & VM_FAULT_ERROR)) {
168                 /*
169                  * We ran out of memory, or some other thing happened
170                  * to us that made us unable to handle the page fault
171                  * gracefully.
172                  */
173                 if (fault & VM_FAULT_OOM) {
174                         goto out_of_memory;
175                 } else if (fault & VM_FAULT_SIGSEGV) {
176                         goto bad_area;
177                 } else if (fault & VM_FAULT_SIGBUS) {
178                         signal = SIGBUS;
179                         goto bad_area;
180                 }
181                 BUG();
182         }
183 
184         if (flags & FAULT_FLAG_ALLOW_RETRY) {
185                 if (fault & VM_FAULT_MAJOR)
186                         current->maj_flt++;
187                 else
188                         current->min_flt++;
189                 if (fault & VM_FAULT_RETRY) {
190                         flags &= ~FAULT_FLAG_ALLOW_RETRY;
191                         flags |= FAULT_FLAG_TRIED;
192 
193                          /* No need to up_read(&mm->mmap_sem) as we would
194                          * have already released it in __lock_page_or_retry
195                          * in mm/filemap.c.
196                          */
197 
198                         goto retry;
199                 }
200         }
201 
202         up_read(&mm->mmap_sem);
203         return;
204 
205   check_expansion:
206         if (!(prev_vma && (prev_vma->vm_flags & VM_GROWSUP) && (address == prev_vma->vm_end))) {
207                 if (!vma)
208                         goto bad_area;
209                 if (!(vma->vm_flags & VM_GROWSDOWN))
210                         goto bad_area;
211                 if (REGION_NUMBER(address) != REGION_NUMBER(vma->vm_start)
212                     || REGION_OFFSET(address) >= RGN_MAP_LIMIT)
213                         goto bad_area;
214                 if (expand_stack(vma, address))
215                         goto bad_area;
216         } else {
217                 vma = prev_vma;
218                 if (REGION_NUMBER(address) != REGION_NUMBER(vma->vm_start)
219                     || REGION_OFFSET(address) >= RGN_MAP_LIMIT)
220                         goto bad_area;
221                 /*
222                  * Since the register backing store is accessed sequentially,
223                  * we disallow growing it by more than a page at a time.
224                  */
225                 if (address > vma->vm_end + PAGE_SIZE - sizeof(long))
226                         goto bad_area;
227                 if (expand_upwards(vma, address))
228                         goto bad_area;
229         }
230         goto good_area;
231 
232   bad_area:
233         up_read(&mm->mmap_sem);
234 #ifdef CONFIG_VIRTUAL_MEM_MAP
235   bad_area_no_up:
236 #endif
237         if ((isr & IA64_ISR_SP)
238             || ((isr & IA64_ISR_NA) && (isr & IA64_ISR_CODE_MASK) == IA64_ISR_CODE_LFETCH))
239         {
240                 /*
241                  * This fault was due to a speculative load or lfetch.fault, set the "ed"
242                  * bit in the psr to ensure forward progress.  (Target register will get a
243                  * NaT for ld.s, lfetch will be canceled.)
244                  */
245                 ia64_psr(regs)->ed = 1;
246                 return;
247         }
248         if (user_mode(regs)) {
249                 si.si_signo = signal;
250                 si.si_errno = 0;
251                 si.si_code = code;
252                 si.si_addr = (void __user *) address;
253                 si.si_isr = isr;
254                 si.si_flags = __ISR_VALID;
255                 force_sig_info(signal, &si, current);
256                 return;
257         }
258 
259   no_context:
260         if ((isr & IA64_ISR_SP)
261             || ((isr & IA64_ISR_NA) && (isr & IA64_ISR_CODE_MASK) == IA64_ISR_CODE_LFETCH))
262         {
263                 /*
264                  * This fault was due to a speculative load or lfetch.fault, set the "ed"
265                  * bit in the psr to ensure forward progress.  (Target register will get a
266                  * NaT for ld.s, lfetch will be canceled.)
267                  */
268                 ia64_psr(regs)->ed = 1;
269                 return;
270         }
271 
272         /*
273          * Since we have no vma's for region 5, we might get here even if the address is
274          * valid, due to the VHPT walker inserting a non present translation that becomes
275          * stale. If that happens, the non present fault handler already purged the stale
276          * translation, which fixed the problem. So, we check to see if the translation is
277          * valid, and return if it is.
278          */
279         if (REGION_NUMBER(address) == 5 && mapped_kernel_page_is_present(address))
280                 return;
281 
282         if (ia64_done_with_exception(regs))
283                 return;
284 
285         /*
286          * Oops. The kernel tried to access some bad page. We'll have to terminate things
287          * with extreme prejudice.
288          */
289         bust_spinlocks(1);
290 
291         if (address < PAGE_SIZE)
292                 printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference (address %016lx)\n", address);
293         else
294                 printk(KERN_ALERT "Unable to handle kernel paging request at "
295                        "virtual address %016lx\n", address);
296         if (die("Oops", regs, isr))
297                 regs = NULL;
298         bust_spinlocks(0);
299         if (regs)
300                 do_exit(SIGKILL);
301         return;
302 
303   out_of_memory:
304         up_read(&mm->mmap_sem);
305         if (!user_mode(regs))
306                 goto no_context;
307         pagefault_out_of_memory();
308 }
309 

~ [ 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