| /* $Id: fault.c,v 1.5 2000/01/26 16:20:29 jsm Exp $ |
| * |
| * This file is subject to the terms and conditions of the GNU General Public |
| * License. See the file "COPYING" in the main directory of this archive |
| * for more details. |
| * |
| * |
| * Copyright (C) 1995, 1996, 1997, 1998 by Ralf Baechle |
| * Copyright 1999 SuSE GmbH (Philipp Rumpf, prumpf@tux.org) |
| * Copyright 1999 Hewlett Packard Co. |
| * |
| */ |
| |
| #include <linux/mm.h> |
| #include <linux/ptrace.h> |
| #include <linux/sched.h> |
| #include <linux/interrupt.h> |
| #include <linux/module.h> |
| |
| #include <asm/uaccess.h> |
| #include <asm/traps.h> |
| |
| #define PRINT_USER_FAULTS /* (turn this on if you want user faults to be */ |
| /* dumped to the console via printk) */ |
| |
| |
| /* Various important other fields */ |
| #define bit22set(x) (x & 0x00000200) |
| #define bits23_25set(x) (x & 0x000001c0) |
| #define isGraphicsFlushRead(x) ((x & 0xfc003fdf) == 0x04001a80) |
| /* extended opcode is 0x6a */ |
| |
| #define BITSSET 0x1c0 /* for identifying LDCW */ |
| |
| |
| DEFINE_PER_CPU(struct exception_data, exception_data); |
| |
| /* |
| * parisc_acctyp(unsigned int inst) -- |
| * Given a PA-RISC memory access instruction, determine if the |
| * the instruction would perform a memory read or memory write |
| * operation. |
| * |
| * This function assumes that the given instruction is a memory access |
| * instruction (i.e. you should really only call it if you know that |
| * the instruction has generated some sort of a memory access fault). |
| * |
| * Returns: |
| * VM_READ if read operation |
| * VM_WRITE if write operation |
| * VM_EXEC if execute operation |
| */ |
| static unsigned long |
| parisc_acctyp(unsigned long code, unsigned int inst) |
| { |
| if (code == 6 || code == 16) |
| return VM_EXEC; |
| |
| switch (inst & 0xf0000000) { |
| case 0x40000000: /* load */ |
| case 0x50000000: /* new load */ |
| return VM_READ; |
| |
| case 0x60000000: /* store */ |
| case 0x70000000: /* new store */ |
| return VM_WRITE; |
| |
| case 0x20000000: /* coproc */ |
| case 0x30000000: /* coproc2 */ |
| if (bit22set(inst)) |
| return VM_WRITE; |
| |
| case 0x0: /* indexed/memory management */ |
| if (bit22set(inst)) { |
| /* |
| * Check for the 'Graphics Flush Read' instruction. |
| * It resembles an FDC instruction, except for bits |
| * 20 and 21. Any combination other than zero will |
| * utilize the block mover functionality on some |
| * older PA-RISC platforms. The case where a block |
| * move is performed from VM to graphics IO space |
| * should be treated as a READ. |
| * |
| * The significance of bits 20,21 in the FDC |
| * instruction is: |
| * |
| * 00 Flush data cache (normal instruction behavior) |
| * 01 Graphics flush write (IO space -> VM) |
| * 10 Graphics flush read (VM -> IO space) |
| * 11 Graphics flush read/write (VM <-> IO space) |
| */ |
| if (isGraphicsFlushRead(inst)) |
| return VM_READ; |
| return VM_WRITE; |
| } else { |
| /* |
| * Check for LDCWX and LDCWS (semaphore instructions). |
| * If bits 23 through 25 are all 1's it is one of |
| * the above two instructions and is a write. |
| * |
| * Note: With the limited bits we are looking at, |
| * this will also catch PROBEW and PROBEWI. However, |
| * these should never get in here because they don't |
| * generate exceptions of the type: |
| * Data TLB miss fault/data page fault |
| * Data memory protection trap |
| */ |
| if (bits23_25set(inst) == BITSSET) |
| return VM_WRITE; |
| } |
| return VM_READ; /* Default */ |
| } |
| return VM_READ; /* Default */ |
| } |
| |
| #undef bit22set |
| #undef bits23_25set |
| #undef isGraphicsFlushRead |
| #undef BITSSET |
| |
| |
| #if 0 |
| /* This is the treewalk to find a vma which is the highest that has |
| * a start < addr. We're using find_vma_prev instead right now, but |
| * we might want to use this at some point in the future. Probably |
| * not, but I want it committed to CVS so I don't lose it :-) |
| */ |
| while (tree != vm_avl_empty) { |
| if (tree->vm_start > addr) { |
| tree = tree->vm_avl_left; |
| } else { |
| prev = tree; |
| if (prev->vm_next == NULL) |
| break; |
| if (prev->vm_next->vm_start > addr) |
| break; |
| tree = tree->vm_avl_right; |
| } |
| } |
| #endif |
| |
| void do_page_fault(struct pt_regs *regs, unsigned long code, |
| unsigned long address) |
| { |
| struct vm_area_struct *vma, *prev_vma; |
| struct task_struct *tsk = current; |
| struct mm_struct *mm = tsk->mm; |
| const struct exception_table_entry *fix; |
| unsigned long acc_type; |
| int fault; |
| |
| if (in_atomic() || !mm) |
| goto no_context; |
| |
| down_read(&mm->mmap_sem); |
| vma = find_vma_prev(mm, address, &prev_vma); |
| if (!vma || address < vma->vm_start) |
| goto check_expansion; |
| /* |
| * Ok, we have a good vm_area for this memory access. We still need to |
| * check the access permissions. |
| */ |
| |
| good_area: |
| |
| acc_type = parisc_acctyp(code,regs->iir); |
| |
| if ((vma->vm_flags & acc_type) != acc_type) |
| goto bad_area; |
| |
| /* |
| * If for any reason at all we couldn't handle the fault, make |
| * sure we exit gracefully rather than endlessly redo the |
| * fault. |
| */ |
| |
| fault = handle_mm_fault(mm, vma, address, (acc_type & VM_WRITE) != 0); |
| if (unlikely(fault & VM_FAULT_ERROR)) { |
| /* |
| * We hit a shared mapping outside of the file, or some |
| * other thing happened to us that made us unable to |
| * handle the page fault gracefully. |
| */ |
| if (fault & VM_FAULT_OOM) |
| goto out_of_memory; |
| else if (fault & VM_FAULT_SIGBUS) |
| goto bad_area; |
| BUG(); |
| } |
| if (fault & VM_FAULT_MAJOR) |
| current->maj_flt++; |
| else |
| current->min_flt++; |
| up_read(&mm->mmap_sem); |
| return; |
| |
| check_expansion: |
| vma = prev_vma; |
| if (vma && (expand_stack(vma, address) == 0)) |
| goto good_area; |
| |
| /* |
| * Something tried to access memory that isn't in our memory map.. |
| */ |
| bad_area: |
| up_read(&mm->mmap_sem); |
| |
| if (user_mode(regs)) { |
| struct siginfo si; |
| |
| #ifdef PRINT_USER_FAULTS |
| printk(KERN_DEBUG "\n"); |
| printk(KERN_DEBUG "do_page_fault() pid=%d command='%s' type=%lu address=0x%08lx\n", |
| task_pid_nr(tsk), tsk->comm, code, address); |
| if (vma) { |
| printk(KERN_DEBUG "vm_start = 0x%08lx, vm_end = 0x%08lx\n", |
| vma->vm_start, vma->vm_end); |
| } |
| show_regs(regs); |
| #endif |
| /* FIXME: actually we need to get the signo and code correct */ |
| si.si_signo = SIGSEGV; |
| si.si_errno = 0; |
| si.si_code = SEGV_MAPERR; |
| si.si_addr = (void __user *) address; |
| force_sig_info(SIGSEGV, &si, current); |
| return; |
| } |
| |
| no_context: |
| |
| if (!user_mode(regs)) { |
| fix = search_exception_tables(regs->iaoq[0]); |
| |
| if (fix) { |
| struct exception_data *d; |
| |
| d = &__get_cpu_var(exception_data); |
| d->fault_ip = regs->iaoq[0]; |
| d->fault_space = regs->isr; |
| d->fault_addr = regs->ior; |
| |
| regs->iaoq[0] = ((fix->fixup) & ~3); |
| |
| /* |
| * NOTE: In some cases the faulting instruction |
| * may be in the delay slot of a branch. We |
| * don't want to take the branch, so we don't |
| * increment iaoq[1], instead we set it to be |
| * iaoq[0]+4, and clear the B bit in the PSW |
| */ |
| |
| regs->iaoq[1] = regs->iaoq[0] + 4; |
| regs->gr[0] &= ~PSW_B; /* IPSW in gr[0] */ |
| |
| return; |
| } |
| } |
| |
| parisc_terminate("Bad Address (null pointer deref?)", regs, code, address); |
| |
| out_of_memory: |
| up_read(&mm->mmap_sem); |
| printk(KERN_CRIT "VM: killing process %s\n", current->comm); |
| if (user_mode(regs)) |
| do_group_exit(SIGKILL); |
| goto no_context; |
| } |
