1 /* $Id: fault.c,v 1.5 2000/01/26 16:20:29 jsm Exp $
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
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.
15 #include <linux/ptrace.h>
16 #include <linux/sched.h>
17 #include <linux/interrupt.h>
18 #include <linux/module.h>
20 #include <asm/uaccess.h>
21 #include <asm/traps.h>
23 #define PRINT_USER_FAULTS /* (turn this on if you want user faults to be */
24 /* dumped to the console via printk) */
27 /* Defines for parisc_acctyp() */
31 /* Various important other fields */
32 #define bit22set(x) (x & 0x00000200)
33 #define bits23_25set(x) (x & 0x000001c0)
34 #define isGraphicsFlushRead(x) ((x & 0xfc003fdf) == 0x04001a80)
35 /* extended opcode is 0x6a */
37 #define BITSSET 0x1c0 /* for identifying LDCW */
40 * parisc_acctyp(unsigned int inst) --
41 * Given a PA-RISC memory access instruction, determine if the
42 * the instruction would perform a memory read or memory write
45 * This function assumes that the given instruction is a memory access
46 * instruction (i.e. you should really only call it if you know that
47 * the instruction has generated some sort of a memory access fault).
50 * VM_READ if read operation
51 * VM_WRITE if write operation
52 * VM_EXEC if execute operation
55 parisc_acctyp(unsigned long code, unsigned int inst)
57 if (code == 6 || code == 16)
60 switch (inst & 0xf0000000) {
61 case 0x40000000: /* load */
62 case 0x50000000: /* new load */
65 case 0x60000000: /* store */
66 case 0x70000000: /* new store */
69 case 0x20000000: /* coproc */
70 case 0x30000000: /* coproc2 */
74 case 0x0: /* indexed/memory management */
77 * Check for the 'Graphics Flush Read' instruction.
78 * It resembles an FDC instruction, except for bits
79 * 20 and 21. Any combination other than zero will
80 * utilize the block mover functionality on some
81 * older PA-RISC platforms. The case where a block
82 * move is performed from VM to graphics IO space
83 * should be treated as a READ.
85 * The significance of bits 20,21 in the FDC
88 * 00 Flush data cache (normal instruction behavior)
89 * 01 Graphics flush write (IO space -> VM)
90 * 10 Graphics flush read (VM -> IO space)
91 * 11 Graphics flush read/write (VM <-> IO space)
93 if (isGraphicsFlushRead(inst))
98 * Check for LDCWX and LDCWS (semaphore instructions).
99 * If bits 23 through 25 are all 1's it is one of
100 * the above two instructions and is a write.
102 * Note: With the limited bits we are looking at,
103 * this will also catch PROBEW and PROBEWI. However,
104 * these should never get in here because they don't
105 * generate exceptions of the type:
106 * Data TLB miss fault/data page fault
107 * Data memory protection trap
109 if (bits23_25set(inst) == BITSSET)
112 return VM_READ; /* Default */
114 return VM_READ; /* Default */
119 #undef isGraphicsFlushRead
124 /* This is the treewalk to find a vma which is the highest that has
125 * a start < addr. We're using find_vma_prev instead right now, but
126 * we might want to use this at some point in the future. Probably
127 * not, but I want it committed to CVS so I don't lose it :-)
129 while (tree != vm_avl_empty) {
130 if (tree->vm_start > addr) {
131 tree = tree->vm_avl_left;
134 if (prev->vm_next == NULL)
136 if (prev->vm_next->vm_start > addr)
138 tree = tree->vm_avl_right;
143 void do_page_fault(struct pt_regs *regs, unsigned long code,
144 unsigned long address)
146 struct vm_area_struct *vma, *prev_vma;
147 struct task_struct *tsk = current;
148 struct mm_struct *mm = tsk->mm;
149 const struct exception_table_entry *fix;
150 unsigned long acc_type;
152 if (in_interrupt() || !mm)
155 down_read(&mm->mmap_sem);
156 vma = find_vma_prev(mm, address, &prev_vma);
157 if (!vma || address < vma->vm_start)
158 goto check_expansion;
160 * Ok, we have a good vm_area for this memory access. We still need to
161 * check the access permissions.
166 acc_type = parisc_acctyp(code,regs->iir);
168 if ((vma->vm_flags & acc_type) != acc_type)
172 * If for any reason at all we couldn't handle the fault, make
173 * sure we exit gracefully rather than endlessly redo the
177 switch (handle_mm_fault(mm, vma, address, (acc_type & VM_WRITE) != 0)) {
186 * We ran out of memory, or some other thing happened
187 * to us that made us unable to handle the page fault
194 up_read(&mm->mmap_sem);
199 if (vma && (expand_stack(vma, address) == 0))
203 * Something tried to access memory that isn't in our memory map..
206 up_read(&mm->mmap_sem);
208 if (user_mode(regs)) {
211 #ifdef PRINT_USER_FAULTS
212 printk(KERN_DEBUG "\n");
213 printk(KERN_DEBUG "do_page_fault() pid=%d command='%s' type=%lu address=0x%08lx\n",
214 tsk->pid, tsk->comm, code, address);
216 printk(KERN_DEBUG "vm_start = 0x%08lx, vm_end = 0x%08lx\n",
217 vma->vm_start, vma->vm_end);
221 /* FIXME: actually we need to get the signo and code correct */
222 si.si_signo = SIGSEGV;
224 si.si_code = SEGV_MAPERR;
225 si.si_addr = (void *) address;
226 force_sig_info(SIGSEGV, &si, current);
232 if (!user_mode(regs)) {
234 fix = search_exception_tables(regs->iaoq[0]);
239 regs->gr[8] = -EFAULT;
243 regs->iaoq[0] += ((fix->skip) & ~3);
246 * NOTE: In some cases the faulting instruction
247 * may be in the delay slot of a branch. We
248 * don't want to take the branch, so we don't
249 * increment iaoq[1], instead we set it to be
250 * iaoq[0]+4, and clear the B bit in the PSW
253 regs->iaoq[1] = regs->iaoq[0] + 4;
254 regs->gr[0] &= ~PSW_B; /* IPSW in gr[0] */
260 parisc_terminate("Bad Address (null pointer deref?)", regs, code, address);
263 up_read(&mm->mmap_sem);
264 printk(KERN_CRIT "VM: killing process %s\n", current->comm);