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1da177e4 LT |
1 | /* $Id: fault.c,v 1.5 2000/01/26 16:20:29 jsm Exp $ |
2 | * | |
3 | * This file is subject to the terms and conditions of the GNU General Public | |
4 | * License. See the file "COPYING" in the main directory of this archive | |
5 | * for more details. | |
6 | * | |
7 | * | |
8 | * Copyright (C) 1995, 1996, 1997, 1998 by Ralf Baechle | |
9 | * Copyright 1999 SuSE GmbH (Philipp Rumpf, prumpf@tux.org) | |
10 | * Copyright 1999 Hewlett Packard Co. | |
11 | * | |
12 | */ | |
13 | ||
14 | #include <linux/mm.h> | |
15 | #include <linux/ptrace.h> | |
16 | #include <linux/sched.h> | |
17 | #include <linux/interrupt.h> | |
18 | #include <linux/module.h> | |
19 | ||
20 | #include <asm/uaccess.h> | |
21 | #include <asm/traps.h> | |
22 | ||
23 | #define PRINT_USER_FAULTS /* (turn this on if you want user faults to be */ | |
24 | /* dumped to the console via printk) */ | |
25 | ||
26 | ||
1da177e4 LT |
27 | /* Various important other fields */ |
28 | #define bit22set(x) (x & 0x00000200) | |
29 | #define bits23_25set(x) (x & 0x000001c0) | |
30 | #define isGraphicsFlushRead(x) ((x & 0xfc003fdf) == 0x04001a80) | |
31 | /* extended opcode is 0x6a */ | |
32 | ||
33 | #define BITSSET 0x1c0 /* for identifying LDCW */ | |
34 | ||
35 | ||
36 | DEFINE_PER_CPU(struct exception_data, exception_data); | |
37 | ||
38 | /* | |
39 | * parisc_acctyp(unsigned int inst) -- | |
40 | * Given a PA-RISC memory access instruction, determine if the | |
41 | * the instruction would perform a memory read or memory write | |
42 | * operation. | |
43 | * | |
44 | * This function assumes that the given instruction is a memory access | |
45 | * instruction (i.e. you should really only call it if you know that | |
46 | * the instruction has generated some sort of a memory access fault). | |
47 | * | |
48 | * Returns: | |
49 | * VM_READ if read operation | |
50 | * VM_WRITE if write operation | |
51 | * VM_EXEC if execute operation | |
52 | */ | |
53 | static unsigned long | |
54 | parisc_acctyp(unsigned long code, unsigned int inst) | |
55 | { | |
56 | if (code == 6 || code == 16) | |
57 | return VM_EXEC; | |
58 | ||
59 | switch (inst & 0xf0000000) { | |
60 | case 0x40000000: /* load */ | |
61 | case 0x50000000: /* new load */ | |
62 | return VM_READ; | |
63 | ||
64 | case 0x60000000: /* store */ | |
65 | case 0x70000000: /* new store */ | |
66 | return VM_WRITE; | |
67 | ||
68 | case 0x20000000: /* coproc */ | |
69 | case 0x30000000: /* coproc2 */ | |
70 | if (bit22set(inst)) | |
71 | return VM_WRITE; | |
72 | ||
73 | case 0x0: /* indexed/memory management */ | |
74 | if (bit22set(inst)) { | |
75 | /* | |
76 | * Check for the 'Graphics Flush Read' instruction. | |
77 | * It resembles an FDC instruction, except for bits | |
78 | * 20 and 21. Any combination other than zero will | |
79 | * utilize the block mover functionality on some | |
80 | * older PA-RISC platforms. The case where a block | |
81 | * move is performed from VM to graphics IO space | |
82 | * should be treated as a READ. | |
83 | * | |
84 | * The significance of bits 20,21 in the FDC | |
85 | * instruction is: | |
86 | * | |
87 | * 00 Flush data cache (normal instruction behavior) | |
88 | * 01 Graphics flush write (IO space -> VM) | |
89 | * 10 Graphics flush read (VM -> IO space) | |
90 | * 11 Graphics flush read/write (VM <-> IO space) | |
91 | */ | |
92 | if (isGraphicsFlushRead(inst)) | |
93 | return VM_READ; | |
94 | return VM_WRITE; | |
95 | } else { | |
96 | /* | |
97 | * Check for LDCWX and LDCWS (semaphore instructions). | |
98 | * If bits 23 through 25 are all 1's it is one of | |
99 | * the above two instructions and is a write. | |
100 | * | |
101 | * Note: With the limited bits we are looking at, | |
102 | * this will also catch PROBEW and PROBEWI. However, | |
103 | * these should never get in here because they don't | |
104 | * generate exceptions of the type: | |
105 | * Data TLB miss fault/data page fault | |
106 | * Data memory protection trap | |
107 | */ | |
108 | if (bits23_25set(inst) == BITSSET) | |
109 | return VM_WRITE; | |
110 | } | |
111 | return VM_READ; /* Default */ | |
112 | } | |
113 | return VM_READ; /* Default */ | |
114 | } | |
115 | ||
116 | #undef bit22set | |
117 | #undef bits23_25set | |
118 | #undef isGraphicsFlushRead | |
119 | #undef BITSSET | |
120 | ||
121 | ||
122 | #if 0 | |
123 | /* This is the treewalk to find a vma which is the highest that has | |
124 | * a start < addr. We're using find_vma_prev instead right now, but | |
125 | * we might want to use this at some point in the future. Probably | |
126 | * not, but I want it committed to CVS so I don't lose it :-) | |
127 | */ | |
128 | while (tree != vm_avl_empty) { | |
129 | if (tree->vm_start > addr) { | |
130 | tree = tree->vm_avl_left; | |
131 | } else { | |
132 | prev = tree; | |
133 | if (prev->vm_next == NULL) | |
134 | break; | |
135 | if (prev->vm_next->vm_start > addr) | |
136 | break; | |
137 | tree = tree->vm_avl_right; | |
138 | } | |
139 | } | |
140 | #endif | |
141 | ||
142 | void do_page_fault(struct pt_regs *regs, unsigned long code, | |
143 | unsigned long address) | |
144 | { | |
145 | struct vm_area_struct *vma, *prev_vma; | |
146 | struct task_struct *tsk = current; | |
147 | struct mm_struct *mm = tsk->mm; | |
148 | const struct exception_table_entry *fix; | |
149 | unsigned long acc_type; | |
150 | ||
6edaf68a | 151 | if (in_atomic() || !mm) |
1da177e4 LT |
152 | goto no_context; |
153 | ||
154 | down_read(&mm->mmap_sem); | |
155 | vma = find_vma_prev(mm, address, &prev_vma); | |
156 | if (!vma || address < vma->vm_start) | |
157 | goto check_expansion; | |
158 | /* | |
159 | * Ok, we have a good vm_area for this memory access. We still need to | |
160 | * check the access permissions. | |
161 | */ | |
162 | ||
163 | good_area: | |
164 | ||
165 | acc_type = parisc_acctyp(code,regs->iir); | |
166 | ||
167 | if ((vma->vm_flags & acc_type) != acc_type) | |
168 | goto bad_area; | |
169 | ||
170 | /* | |
171 | * If for any reason at all we couldn't handle the fault, make | |
172 | * sure we exit gracefully rather than endlessly redo the | |
173 | * fault. | |
174 | */ | |
175 | ||
176 | switch (handle_mm_fault(mm, vma, address, (acc_type & VM_WRITE) != 0)) { | |
6e346228 | 177 | case VM_FAULT_MINOR: |
1da177e4 LT |
178 | ++current->min_flt; |
179 | break; | |
6e346228 | 180 | case VM_FAULT_MAJOR: |
1da177e4 LT |
181 | ++current->maj_flt; |
182 | break; | |
6e346228 | 183 | case VM_FAULT_SIGBUS: |
1da177e4 | 184 | /* |
67a5a59d | 185 | * We hit a shared mapping outside of the file, or some |
6e346228 LT |
186 | * other thing happened to us that made us unable to |
187 | * handle the page fault gracefully. | |
1da177e4 LT |
188 | */ |
189 | goto bad_area; | |
190 | default: | |
191 | goto out_of_memory; | |
192 | } | |
193 | up_read(&mm->mmap_sem); | |
194 | return; | |
195 | ||
196 | check_expansion: | |
197 | vma = prev_vma; | |
198 | if (vma && (expand_stack(vma, address) == 0)) | |
199 | goto good_area; | |
200 | ||
201 | /* | |
202 | * Something tried to access memory that isn't in our memory map.. | |
203 | */ | |
204 | bad_area: | |
205 | up_read(&mm->mmap_sem); | |
206 | ||
207 | if (user_mode(regs)) { | |
208 | struct siginfo si; | |
209 | ||
210 | #ifdef PRINT_USER_FAULTS | |
211 | printk(KERN_DEBUG "\n"); | |
212 | printk(KERN_DEBUG "do_page_fault() pid=%d command='%s' type=%lu address=0x%08lx\n", | |
213 | tsk->pid, tsk->comm, code, address); | |
214 | if (vma) { | |
215 | printk(KERN_DEBUG "vm_start = 0x%08lx, vm_end = 0x%08lx\n", | |
216 | vma->vm_start, vma->vm_end); | |
217 | } | |
218 | show_regs(regs); | |
219 | #endif | |
220 | /* FIXME: actually we need to get the signo and code correct */ | |
221 | si.si_signo = SIGSEGV; | |
222 | si.si_errno = 0; | |
223 | si.si_code = SEGV_MAPERR; | |
224 | si.si_addr = (void __user *) address; | |
225 | force_sig_info(SIGSEGV, &si, current); | |
226 | return; | |
227 | } | |
228 | ||
229 | no_context: | |
230 | ||
231 | if (!user_mode(regs)) { | |
232 | fix = search_exception_tables(regs->iaoq[0]); | |
233 | ||
234 | if (fix) { | |
235 | struct exception_data *d; | |
236 | ||
237 | d = &__get_cpu_var(exception_data); | |
238 | d->fault_ip = regs->iaoq[0]; | |
239 | d->fault_space = regs->isr; | |
240 | d->fault_addr = regs->ior; | |
241 | ||
242 | regs->iaoq[0] = ((fix->fixup) & ~3); | |
243 | ||
244 | /* | |
245 | * NOTE: In some cases the faulting instruction | |
246 | * may be in the delay slot of a branch. We | |
247 | * don't want to take the branch, so we don't | |
248 | * increment iaoq[1], instead we set it to be | |
249 | * iaoq[0]+4, and clear the B bit in the PSW | |
250 | */ | |
251 | ||
252 | regs->iaoq[1] = regs->iaoq[0] + 4; | |
253 | regs->gr[0] &= ~PSW_B; /* IPSW in gr[0] */ | |
254 | ||
255 | return; | |
256 | } | |
257 | } | |
258 | ||
259 | parisc_terminate("Bad Address (null pointer deref?)", regs, code, address); | |
260 | ||
261 | out_of_memory: | |
262 | up_read(&mm->mmap_sem); | |
263 | printk(KERN_CRIT "VM: killing process %s\n", current->comm); | |
264 | if (user_mode(regs)) | |
265 | do_exit(SIGKILL); | |
266 | goto no_context; | |
267 | } |