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git.proxmox.com Git - mirror_ubuntu-kernels.git/blob - arch/ia64/mm/fault.c
1 // SPDX-License-Identifier: GPL-2.0
3 * MMU fault handling support.
5 * Copyright (C) 1998-2002 Hewlett-Packard Co
6 * David Mosberger-Tang <davidm@hpl.hp.com>
8 #include <linux/sched/signal.h>
9 #include <linux/kernel.h>
11 #include <linux/extable.h>
12 #include <linux/interrupt.h>
13 #include <linux/kprobes.h>
14 #include <linux/kdebug.h>
15 #include <linux/prefetch.h>
16 #include <linux/uaccess.h>
18 #include <asm/processor.h>
19 #include <asm/exception.h>
21 extern int die(char *, struct pt_regs
*, long);
24 * Return TRUE if ADDRESS points at a page in the kernel's mapped segment
25 * (inside region 5, on ia64) and that page is present.
28 mapped_kernel_page_is_present (unsigned long address
)
36 pgd
= pgd_offset_k(address
);
37 if (pgd_none(*pgd
) || pgd_bad(*pgd
))
40 p4d
= p4d_offset(pgd
, address
);
41 if (p4d_none(*p4d
) || p4d_bad(*p4d
))
44 pud
= pud_offset(p4d
, address
);
45 if (pud_none(*pud
) || pud_bad(*pud
))
48 pmd
= pmd_offset(pud
, address
);
49 if (pmd_none(*pmd
) || pmd_bad(*pmd
))
52 ptep
= pte_offset_kernel(pmd
, address
);
57 return pte_present(pte
);
60 # define VM_READ_BIT 0
61 # define VM_WRITE_BIT 1
62 # define VM_EXEC_BIT 2
65 ia64_do_page_fault (unsigned long address
, unsigned long isr
, struct pt_regs
*regs
)
67 int signal
= SIGSEGV
, code
= SEGV_MAPERR
;
68 struct vm_area_struct
*vma
, *prev_vma
;
69 struct mm_struct
*mm
= current
->mm
;
72 unsigned int flags
= FAULT_FLAG_DEFAULT
;
74 mask
= ((((isr
>> IA64_ISR_X_BIT
) & 1UL) << VM_EXEC_BIT
)
75 | (((isr
>> IA64_ISR_W_BIT
) & 1UL) << VM_WRITE_BIT
));
77 /* mmap_lock is performance critical.... */
78 prefetchw(&mm
->mmap_lock
);
81 * If we're in an interrupt or have no user context, we must not take the fault..
83 if (faulthandler_disabled() || !mm
)
86 #ifdef CONFIG_VIRTUAL_MEM_MAP
88 * If fault is in region 5 and we are in the kernel, we may already
89 * have the mmap_lock (pfn_valid macro is called during mmap). There
90 * is no vma for region 5 addr's anyway, so skip getting the semaphore
91 * and go directly to the exception handling code.
94 if ((REGION_NUMBER(address
) == 5) && !user_mode(regs
))
99 * This is to handle the kprobes on user space access instructions
101 if (kprobe_page_fault(regs
, TRAP_BRKPT
))
105 flags
|= FAULT_FLAG_USER
;
107 flags
|= FAULT_FLAG_WRITE
;
111 vma
= find_vma_prev(mm
, address
, &prev_vma
);
112 if (!vma
&& !prev_vma
)
116 * find_vma_prev() returns vma such that address < vma->vm_end or NULL
118 * May find no vma, but could be that the last vm area is the
119 * register backing store that needs to expand upwards, in
120 * this case vma will be null, but prev_vma will ne non-null
122 if (( !vma
&& prev_vma
) || (address
< vma
->vm_start
) )
123 goto check_expansion
;
128 /* OK, we've got a good vm_area for this memory area. Check the access permissions: */
130 # if (((1 << VM_READ_BIT) != VM_READ || (1 << VM_WRITE_BIT) != VM_WRITE) \
131 || (1 << VM_EXEC_BIT) != VM_EXEC)
132 # error File is out of sync with <linux/mm.h>. Please update.
135 if (((isr
>> IA64_ISR_R_BIT
) & 1UL) && (!(vma
->vm_flags
& (VM_READ
| VM_WRITE
))))
138 if ((vma
->vm_flags
& mask
) != mask
)
142 * If for any reason at all we couldn't handle the fault, make
143 * sure we exit gracefully rather than endlessly redo the
146 fault
= handle_mm_fault(vma
, address
, flags
);
148 if (fault_signal_pending(fault
, regs
))
151 if (unlikely(fault
& VM_FAULT_ERROR
)) {
153 * We ran out of memory, or some other thing happened
154 * to us that made us unable to handle the page fault
157 if (fault
& VM_FAULT_OOM
) {
159 } else if (fault
& VM_FAULT_SIGSEGV
) {
161 } else if (fault
& VM_FAULT_SIGBUS
) {
168 if (flags
& FAULT_FLAG_ALLOW_RETRY
) {
169 if (fault
& VM_FAULT_MAJOR
)
173 if (fault
& VM_FAULT_RETRY
) {
174 flags
|= FAULT_FLAG_TRIED
;
176 /* No need to mmap_read_unlock(mm) as we would
177 * have already released it in __lock_page_or_retry
185 mmap_read_unlock(mm
);
189 if (!(prev_vma
&& (prev_vma
->vm_flags
& VM_GROWSUP
) && (address
== prev_vma
->vm_end
))) {
192 if (!(vma
->vm_flags
& VM_GROWSDOWN
))
194 if (REGION_NUMBER(address
) != REGION_NUMBER(vma
->vm_start
)
195 || REGION_OFFSET(address
) >= RGN_MAP_LIMIT
)
197 if (expand_stack(vma
, address
))
201 if (REGION_NUMBER(address
) != REGION_NUMBER(vma
->vm_start
)
202 || REGION_OFFSET(address
) >= RGN_MAP_LIMIT
)
205 * Since the register backing store is accessed sequentially,
206 * we disallow growing it by more than a page at a time.
208 if (address
> vma
->vm_end
+ PAGE_SIZE
- sizeof(long))
210 if (expand_upwards(vma
, address
))
216 mmap_read_unlock(mm
);
217 #ifdef CONFIG_VIRTUAL_MEM_MAP
220 if ((isr
& IA64_ISR_SP
)
221 || ((isr
& IA64_ISR_NA
) && (isr
& IA64_ISR_CODE_MASK
) == IA64_ISR_CODE_LFETCH
))
224 * This fault was due to a speculative load or lfetch.fault, set the "ed"
225 * bit in the psr to ensure forward progress. (Target register will get a
226 * NaT for ld.s, lfetch will be canceled.)
228 ia64_psr(regs
)->ed
= 1;
231 if (user_mode(regs
)) {
232 force_sig_fault(signal
, code
, (void __user
*) address
,
233 0, __ISR_VALID
, isr
);
238 if ((isr
& IA64_ISR_SP
)
239 || ((isr
& IA64_ISR_NA
) && (isr
& IA64_ISR_CODE_MASK
) == IA64_ISR_CODE_LFETCH
))
242 * This fault was due to a speculative load or lfetch.fault, set the "ed"
243 * bit in the psr to ensure forward progress. (Target register will get a
244 * NaT for ld.s, lfetch will be canceled.)
246 ia64_psr(regs
)->ed
= 1;
251 * Since we have no vma's for region 5, we might get here even if the address is
252 * valid, due to the VHPT walker inserting a non present translation that becomes
253 * stale. If that happens, the non present fault handler already purged the stale
254 * translation, which fixed the problem. So, we check to see if the translation is
255 * valid, and return if it is.
257 if (REGION_NUMBER(address
) == 5 && mapped_kernel_page_is_present(address
))
260 if (ia64_done_with_exception(regs
))
264 * Oops. The kernel tried to access some bad page. We'll have to terminate things
265 * with extreme prejudice.
269 if (address
< PAGE_SIZE
)
270 printk(KERN_ALERT
"Unable to handle kernel NULL pointer dereference (address %016lx)\n", address
);
272 printk(KERN_ALERT
"Unable to handle kernel paging request at "
273 "virtual address %016lx\n", address
);
274 if (die("Oops", regs
, isr
))
282 mmap_read_unlock(mm
);
283 if (!user_mode(regs
))
285 pagefault_out_of_memory();