Skip to content
Navigation Menu
Toggle navigation
Sign in
In this repository
All GitHub Enterprise
↵
Jump to
↵
No suggested jump to results
In this repository
All GitHub Enterprise
↵
Jump to
↵
In this organization
All GitHub Enterprise
↵
Jump to
↵
In this repository
All GitHub Enterprise
↵
Jump to
↵
Sign in
Reseting focus
You signed in with another tab or window.
Reload
to refresh your session.
You signed out in another tab or window.
Reload
to refresh your session.
You switched accounts on another tab or window.
Reload
to refresh your session.
Dismiss alert
{{ message }}
mariux64
/
linux
Public
Notifications
You must be signed in to change notification settings
Fork
0
Star
0
Code
Issues
2
Pull requests
0
Actions
Projects
0
Wiki
Security
Insights
Additional navigation options
Code
Issues
Pull requests
Actions
Projects
Wiki
Security
Insights
Files
6edaf68
Documentation
arch
alpha
arm
arm26
boot
kernel
lib
machine
mm
Makefile
extable.c
fault.c
fault.h
init.c
memc.c
proc-funcs.S
small_page.c
nwfpe
ACKNOWLEDGEMENTS
Kconfig
Kconfig.debug
Makefile
defconfig
avr32
cris
frv
h8300
i386
ia64
m32r
m68k
m68knommu
mips
parisc
powerpc
ppc
s390
sh
sh64
sparc
sparc64
um
v850
x86_64
xtensa
block
crypto
drivers
fs
include
init
ipc
kernel
lib
mm
net
scripts
security
sound
usr
.gitignore
COPYING
CREDITS
Kbuild
MAINTAINERS
Makefile
README
REPORTING-BUGS
Breadcrumbs
linux
/
arch
/
arm26
/
mm
/
fault.c
Copy path
Blame
Blame
Latest commit
History
History
314 lines (271 loc) · 7.09 KB
Breadcrumbs
linux
/
arch
/
arm26
/
mm
/
fault.c
Top
File metadata and controls
Code
Blame
314 lines (271 loc) · 7.09 KB
Raw
/* * linux/arch/arm26/mm/fault.c * * Copyright (C) 1995 Linus Torvalds * Modifications for ARM processor (c) 1995-2001 Russell King * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include <linux/signal.h> #include <linux/sched.h> #include <linux/kernel.h> #include <linux/errno.h> #include <linux/string.h> #include <linux/types.h> #include <linux/ptrace.h> #include <linux/mman.h> #include <linux/mm.h> #include <linux/interrupt.h> #include <linux/proc_fs.h> #include <linux/init.h> #include <asm/system.h> #include <asm/pgtable.h> #include <asm/uaccess.h> //FIXME this header may be bogusly included #include "fault.h" #define FAULT_CODE_LDRSTRPOST 0x80 #define FAULT_CODE_LDRSTRPRE 0x40 #define FAULT_CODE_LDRSTRREG 0x20 #define FAULT_CODE_LDMSTM 0x10 #define FAULT_CODE_LDCSTC 0x08 #define FAULT_CODE_PREFETCH 0x04 #define FAULT_CODE_WRITE 0x02 #define FAULT_CODE_FORCECOW 0x01 #define DO_COW(m) ((m) & (FAULT_CODE_WRITE|FAULT_CODE_FORCECOW)) #define READ_FAULT(m) (!((m) & FAULT_CODE_WRITE)) #define DEBUG /* * This is useful to dump out the page tables associated with * 'addr' in mm 'mm'. */ void show_pte(struct mm_struct *mm, unsigned long addr) { pgd_t *pgd; if (!mm) mm = &init_mm; printk(KERN_ALERT "pgd = %p\n", mm->pgd); pgd = pgd_offset(mm, addr); printk(KERN_ALERT "[%08lx] *pgd=%08lx", addr, pgd_val(*pgd)); do { pmd_t *pmd; pte_t *pte; pmd = pmd_offset(pgd, addr); if (pmd_none(*pmd)) break; if (pmd_bad(*pmd)) { printk("(bad)"); break; } /* We must not map this if we have highmem enabled */ /* FIXME */ pte = pte_offset_map(pmd, addr); printk(", *pte=%08lx", pte_val(*pte)); pte_unmap(pte); } while(0); printk("\n"); } /* * Oops. The kernel tried to access some page that wasn't present. */ static void __do_kernel_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr, struct pt_regs *regs) { /* * Are we prepared to handle this kernel fault? */ if (fixup_exception(regs)) return; /* * No handler, we'll have to terminate things with extreme prejudice. */ bust_spinlocks(1); printk(KERN_ALERT "Unable to handle kernel %s at virtual address %08lx\n", (addr < PAGE_SIZE) ? "NULL pointer dereference" : "paging request", addr); show_pte(mm, addr); die("Oops", regs, fsr); bust_spinlocks(0); do_exit(SIGKILL); } /* * Something tried to access memory that isn't in our memory map.. * User mode accesses just cause a SIGSEGV */ static void __do_user_fault(struct task_struct *tsk, unsigned long addr, unsigned int fsr, int code, struct pt_regs *regs) { struct siginfo si; #ifdef CONFIG_DEBUG_USER printk("%s: unhandled page fault at 0x%08lx, code 0x%03x\n", tsk->comm, addr, fsr); show_pte(tsk->mm, addr); show_regs(regs); //dump_backtrace(regs, tsk); // FIXME ARM32 dropped this - why? while(1); //FIXME - hack to stop debug going nutso #endif tsk->thread.address = addr; tsk->thread.error_code = fsr; tsk->thread.trap_no = 14; si.si_signo = SIGSEGV; si.si_errno = 0; si.si_code = code; si.si_addr = (void *)addr; force_sig_info(SIGSEGV, &si, tsk); } static int __do_page_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr, struct task_struct *tsk) { struct vm_area_struct *vma; int fault, mask; vma = find_vma(mm, addr); fault = -2; /* bad map area */ if (!vma) goto out; if (vma->vm_start > addr) goto check_stack; /* * Ok, we have a good vm_area for this * memory access, so we can handle it. */ good_area: if (READ_FAULT(fsr)) /* read? */ mask = VM_READ|VM_EXEC|VM_WRITE; else mask = VM_WRITE; fault = -1; /* bad access type */ if (!(vma->vm_flags & mask)) goto out; /* * If for any reason at all we couldn't handle * the fault, make sure we exit gracefully rather * than endlessly redo the fault. */ survive: fault = handle_mm_fault(mm, vma, addr & PAGE_MASK, DO_COW(fsr)); /* * Handle the "normal" cases first - successful and sigbus */ switch (fault) { case VM_FAULT_MAJOR: tsk->maj_flt++; return fault; case VM_FAULT_MINOR: tsk->min_flt++; case VM_FAULT_SIGBUS: return fault; } fault = -3; /* out of memory */ if (!is_init(tsk)) goto out; /* * If we are out of memory for pid1, * sleep for a while and retry */ yield(); goto survive; check_stack: if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr)) goto good_area; out: return fault; } int do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs) { struct task_struct *tsk; struct mm_struct *mm; int fault; tsk = current; mm = tsk->mm; /* * If we're in an interrupt or have no user * context, we must not take the fault.. */ if (in_atomic() || !mm) goto no_context; down_read(&mm->mmap_sem); fault = __do_page_fault(mm, addr, fsr, tsk); up_read(&mm->mmap_sem); /* * Handle the "normal" case first */ switch (fault) { case VM_FAULT_MINOR: case VM_FAULT_MAJOR: return 0; case VM_FAULT_SIGBUS: goto do_sigbus; } /* * If we are in kernel mode at this point, we * have no context to handle this fault with. * FIXME - is this test right? */ if (!user_mode(regs)){ goto no_context; } if (fault == -3) { /* * We ran out of memory, or some other thing happened to * us that made us unable to handle the page fault gracefully. */ printk("VM: killing process %s\n", tsk->comm); do_exit(SIGKILL); } else{ __do_user_fault(tsk, addr, fsr, fault == -1 ? SEGV_ACCERR : SEGV_MAPERR, regs); } return 0; /* * We ran out of memory, or some other thing happened to us that made * us unable to handle the page fault gracefully. */ do_sigbus: /* * Send a sigbus, regardless of whether we were in kernel * or user mode. */ tsk->thread.address = addr; //FIXME - need other bits setting? tsk->thread.error_code = fsr; tsk->thread.trap_no = 14; force_sig(SIGBUS, tsk); #ifdef CONFIG_DEBUG_USER printk(KERN_DEBUG "%s: sigbus at 0x%08lx, pc=0x%08lx\n", current->comm, addr, instruction_pointer(regs)); #endif /* Kernel mode? Handle exceptions or die */ if (user_mode(regs)) return 0; no_context: __do_kernel_fault(mm, addr, fsr, regs); return 0; } /* * Handle a data abort. Note that we have to handle a range of addresses * on ARM2/3 for ldm. If both pages are zero-mapped, then we have to force * a copy-on-write. However, on the second page, we always force COW. */ asmlinkage void do_DataAbort(unsigned long min_addr, unsigned long max_addr, int mode, struct pt_regs *regs) { do_page_fault(min_addr, mode, regs); if ((min_addr ^ max_addr) >> PAGE_SHIFT){ do_page_fault(max_addr, mode | FAULT_CODE_FORCECOW, regs); } } asmlinkage int do_PrefetchAbort(unsigned long addr, struct pt_regs *regs) { #if 0 if (the memc mapping for this page exists) { printk ("Page in, but got abort (undefined instruction?)\n"); return 0; } #endif do_page_fault(addr, FAULT_CODE_PREFETCH, regs); return 1; }
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
You can’t perform that action at this time.