diff options
Diffstat (limited to 'kernel/arch/avr32/mm/fault.c')
| -rw-r--r-- | kernel/arch/avr32/mm/fault.c | 268 |
1 files changed, 268 insertions, 0 deletions
diff --git a/kernel/arch/avr32/mm/fault.c b/kernel/arch/avr32/mm/fault.c new file mode 100644 index 000000000..c03533937 --- /dev/null +++ b/kernel/arch/avr32/mm/fault.c @@ -0,0 +1,268 @@ +/* + * Copyright (C) 2004-2006 Atmel Corporation + * + * Based on linux/arch/sh/mm/fault.c: + * Copyright (C) 1999 Niibe Yutaka + * + * 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/mm.h> +#include <linux/module.h> +#include <linux/pagemap.h> +#include <linux/kdebug.h> +#include <linux/kprobes.h> +#include <linux/uaccess.h> + +#include <asm/mmu_context.h> +#include <asm/sysreg.h> +#include <asm/tlb.h> + +#ifdef CONFIG_KPROBES +static inline int notify_page_fault(struct pt_regs *regs, int trap) +{ + int ret = 0; + + if (!user_mode(regs)) { + if (kprobe_running() && kprobe_fault_handler(regs, trap)) + ret = 1; + } + + return ret; +} +#else +static inline int notify_page_fault(struct pt_regs *regs, int trap) +{ + return 0; +} +#endif + +int exception_trace = 1; + +/* + * This routine handles page faults. It determines the address and the + * problem, and then passes it off to one of the appropriate routines. + * + * ecr is the Exception Cause Register. Possible values are: + * 6: Protection fault (instruction access) + * 15: Protection fault (read access) + * 16: Protection fault (write access) + * 20: Page not found (instruction access) + * 24: Page not found (read access) + * 28: Page not found (write access) + */ +asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs) +{ + struct task_struct *tsk; + struct mm_struct *mm; + struct vm_area_struct *vma; + const struct exception_table_entry *fixup; + unsigned long address; + unsigned long page; + long signr; + int code; + int fault; + unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + + if (notify_page_fault(regs, ecr)) + return; + + address = sysreg_read(TLBEAR); + + tsk = current; + mm = tsk->mm; + + signr = SIGSEGV; + code = SEGV_MAPERR; + + /* + * If we're in an interrupt or have no user context, we must + * not take the fault... + */ + if (faulthandler_disabled() || !mm || regs->sr & SYSREG_BIT(GM)) + goto no_context; + + local_irq_enable(); + + if (user_mode(regs)) + flags |= FAULT_FLAG_USER; +retry: + down_read(&mm->mmap_sem); + + vma = find_vma(mm, address); + if (!vma) + goto bad_area; + if (vma->vm_start <= address) + goto good_area; + if (!(vma->vm_flags & VM_GROWSDOWN)) + goto bad_area; + if (expand_stack(vma, address)) + goto bad_area; + + /* + * Ok, we have a good vm_area for this memory access, so we + * can handle it... + */ +good_area: + code = SEGV_ACCERR; + + switch (ecr) { + case ECR_PROTECTION_X: + case ECR_TLB_MISS_X: + if (!(vma->vm_flags & VM_EXEC)) + goto bad_area; + break; + case ECR_PROTECTION_R: + case ECR_TLB_MISS_R: + if (!(vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC))) + goto bad_area; + break; + case ECR_PROTECTION_W: + case ECR_TLB_MISS_W: + if (!(vma->vm_flags & VM_WRITE)) + goto bad_area; + flags |= FAULT_FLAG_WRITE; + break; + default: + panic("Unhandled case %lu in do_page_fault!", ecr); + } + + /* + * 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, flags); + + if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + return; + + if (unlikely(fault & VM_FAULT_ERROR)) { + if (fault & VM_FAULT_OOM) + goto out_of_memory; + else if (fault & VM_FAULT_SIGSEGV) + goto bad_area; + else if (fault & VM_FAULT_SIGBUS) + goto do_sigbus; + BUG(); + } + + if (flags & FAULT_FLAG_ALLOW_RETRY) { + if (fault & VM_FAULT_MAJOR) + tsk->maj_flt++; + else + tsk->min_flt++; + if (fault & VM_FAULT_RETRY) { + flags &= ~FAULT_FLAG_ALLOW_RETRY; + flags |= FAULT_FLAG_TRIED; + + /* + * No need to up_read(&mm->mmap_sem) as we would have + * already released it in __lock_page_or_retry() in + * mm/filemap.c. + */ + goto retry; + } + } + + up_read(&mm->mmap_sem); + return; + + /* + * Something tried to access memory that isn't in our memory + * map. Fix it, but check if it's kernel or user first... + */ +bad_area: + up_read(&mm->mmap_sem); + + if (user_mode(regs)) { + if (exception_trace && printk_ratelimit()) + printk("%s%s[%d]: segfault at %08lx pc %08lx " + "sp %08lx ecr %lu\n", + is_global_init(tsk) ? KERN_EMERG : KERN_INFO, + tsk->comm, tsk->pid, address, regs->pc, + regs->sp, ecr); + _exception(SIGSEGV, regs, code, address); + return; + } + +no_context: + /* Are we prepared to handle this kernel fault? */ + fixup = search_exception_tables(regs->pc); + if (fixup) { + regs->pc = fixup->fixup; + return; + } + + /* + * Oops. The kernel tried to access some bad page. We'll have + * to terminate things with extreme prejudice. + */ + if (address < PAGE_SIZE) + printk(KERN_ALERT + "Unable to handle kernel NULL pointer dereference"); + else + printk(KERN_ALERT + "Unable to handle kernel paging request"); + printk(" at virtual address %08lx\n", address); + + page = sysreg_read(PTBR); + printk(KERN_ALERT "ptbr = %08lx", page); + if (address >= TASK_SIZE) + page = (unsigned long)swapper_pg_dir; + if (page) { + page = ((unsigned long *)page)[address >> 22]; + printk(" pgd = %08lx", page); + if (page & _PAGE_PRESENT) { + page &= PAGE_MASK; + address &= 0x003ff000; + page = ((unsigned long *)__va(page))[address >> PAGE_SHIFT]; + printk(" pte = %08lx", page); + } + } + printk("\n"); + die("Kernel access of bad area", regs, signr); + return; + + /* + * We ran out of memory, or some other thing happened to us + * that made us unable to handle the page fault gracefully. + */ +out_of_memory: + up_read(&mm->mmap_sem); + if (!user_mode(regs)) + goto no_context; + pagefault_out_of_memory(); + return; + +do_sigbus: + up_read(&mm->mmap_sem); + + /* Kernel mode? Handle exceptions or die */ + signr = SIGBUS; + code = BUS_ADRERR; + if (!user_mode(regs)) + goto no_context; + + if (exception_trace) + printk("%s%s[%d]: bus error at %08lx pc %08lx " + "sp %08lx ecr %lu\n", + is_global_init(tsk) ? KERN_EMERG : KERN_INFO, + tsk->comm, tsk->pid, address, regs->pc, + regs->sp, ecr); + + _exception(SIGBUS, regs, BUS_ADRERR, address); +} + +asmlinkage void do_bus_error(unsigned long addr, int write_access, + struct pt_regs *regs) +{ + printk(KERN_ALERT + "Bus error at physical address 0x%08lx (%s access)\n", + addr, write_access ? "write" : "read"); + printk(KERN_INFO "DTLB dump:\n"); + dump_dtlb(); + die("Bus Error", regs, SIGKILL); +} |