[PARISC] whitespace cleanups and unify 32/64bit user-access assembler inlines
[linux-2.6.git] / arch / parisc / mm / fault.c
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
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
151         if (in_atomic() || !mm)
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)) {
177               case VM_FAULT_MINOR:
178                 ++current->min_flt;
179                 break;
180               case VM_FAULT_MAJOR:
181                 ++current->maj_flt;
182                 break;
183               case VM_FAULT_SIGBUS:
184                 /*
185                  * We hit a shared mapping outside of the file, or some
186                  * other thing happened to us that made us unable to
187                  * handle the page fault gracefully.
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 }