| /* MN10300 MMU Fault handler |
| * |
| * Copyright (C) 2007 Matsushita Electric Industrial Co., Ltd. |
| * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. |
| * Modified by David Howells (dhowells@redhat.com) |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public Licence |
| * as published by the Free Software Foundation; either version |
| * 2 of the Licence, or (at your option) any later version. |
| */ |
| |
| #include <linux/signal.h> |
| #include <linux/sched.h> |
| #include <linux/kernel.h> |
| #include <linux/errno.h> |
| #include <linux/string.h> |
| #include <linux/types.h> |
| #include <linux/ptrace.h> |
| #include <linux/mman.h> |
| #include <linux/mm.h> |
| #include <linux/smp.h> |
| #include <linux/interrupt.h> |
| #include <linux/init.h> |
| #include <linux/vt_kern.h> /* For unblank_screen() */ |
| #include <linux/uaccess.h> |
| |
| #include <asm/pgalloc.h> |
| #include <asm/hardirq.h> |
| #include <asm/cpu-regs.h> |
| #include <asm/debugger.h> |
| #include <asm/gdb-stub.h> |
| |
| /* |
| * Unlock any spinlocks which will prevent us from getting the |
| * message out |
| */ |
| void bust_spinlocks(int yes) |
| { |
| if (yes) { |
| oops_in_progress = 1; |
| } else { |
| int loglevel_save = console_loglevel; |
| #ifdef CONFIG_VT |
| unblank_screen(); |
| #endif |
| oops_in_progress = 0; |
| /* |
| * OK, the message is on the console. Now we call printk() |
| * without oops_in_progress set so that printk will give klogd |
| * a poke. Hold onto your hats... |
| */ |
| console_loglevel = 15; /* NMI oopser may have shut the console |
| * up */ |
| printk(" "); |
| console_loglevel = loglevel_save; |
| } |
| } |
| |
| void do_BUG(const char *file, int line) |
| { |
| bust_spinlocks(1); |
| printk(KERN_EMERG CUT_HERE); |
| printk(KERN_EMERG "kernel BUG at %s:%d!\n", file, line); |
| } |
| |
| #if 0 |
| static void print_pagetable_entries(pgd_t *pgdir, unsigned long address) |
| { |
| pgd_t *pgd; |
| pmd_t *pmd; |
| pte_t *pte; |
| |
| pgd = pgdir + __pgd_offset(address); |
| printk(KERN_DEBUG "pgd entry %p: %016Lx\n", |
| pgd, (long long) pgd_val(*pgd)); |
| |
| if (!pgd_present(*pgd)) { |
| printk(KERN_DEBUG "... pgd not present!\n"); |
| return; |
| } |
| pmd = pmd_offset(pgd, address); |
| printk(KERN_DEBUG "pmd entry %p: %016Lx\n", |
| pmd, (long long)pmd_val(*pmd)); |
| |
| if (!pmd_present(*pmd)) { |
| printk(KERN_DEBUG "... pmd not present!\n"); |
| return; |
| } |
| pte = pte_offset(pmd, address); |
| printk(KERN_DEBUG "pte entry %p: %016Lx\n", |
| pte, (long long) pte_val(*pte)); |
| |
| if (!pte_present(*pte)) |
| printk(KERN_DEBUG "... pte not present!\n"); |
| } |
| #endif |
| |
| /* |
| * This routine handles page faults. It determines the address, |
| * and the problem, and then passes it off to one of the appropriate |
| * routines. |
| * |
| * fault_code: |
| * - LSW: either MMUFCR_IFC or MMUFCR_DFC as appropriate |
| * - MSW: 0 if data access, 1 if instruction access |
| * - bit 0: TLB miss flag |
| * - bit 1: initial write |
| * - bit 2: page invalid |
| * - bit 3: protection violation |
| * - bit 4: accessor (0=user 1=kernel) |
| * - bit 5: 0=read 1=write |
| * - bit 6-8: page protection spec |
| * - bit 9: illegal address |
| * - bit 16: 0=data 1=ins |
| * |
| */ |
| asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long fault_code, |
| unsigned long address) |
| { |
| struct vm_area_struct *vma; |
| struct task_struct *tsk; |
| struct mm_struct *mm; |
| unsigned long page; |
| siginfo_t info; |
| int fault; |
| unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; |
| |
| #ifdef CONFIG_GDBSTUB |
| /* handle GDB stub causing a fault */ |
| if (gdbstub_busy) { |
| gdbstub_exception(regs, TBR & TBR_INT_CODE); |
| return; |
| } |
| #endif |
| |
| #if 0 |
| printk(KERN_DEBUG "--- do_page_fault(%p,%s:%04lx,%08lx)\n", |
| regs, |
| fault_code & 0x10000 ? "ins" : "data", |
| fault_code & 0xffff, address); |
| #endif |
| |
| tsk = current; |
| |
| /* |
| * We fault-in kernel-space virtual memory on-demand. The |
| * 'reference' page table is init_mm.pgd. |
| * |
| * NOTE! We MUST NOT take any locks for this case. We may |
| * be in an interrupt or a critical region, and should |
| * only copy the information from the master page table, |
| * nothing more. |
| * |
| * This verifies that the fault happens in kernel space |
| * and that the fault was a page not present (invalid) error |
| */ |
| if (address >= VMALLOC_START && address < VMALLOC_END && |
| (fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_SR && |
| (fault_code & MMUFCR_xFC_PGINVAL) == MMUFCR_xFC_PGINVAL |
| ) |
| goto vmalloc_fault; |
| |
| mm = tsk->mm; |
| info.si_code = SEGV_MAPERR; |
| |
| /* |
| * If we're in an interrupt or have no user |
| * context, we must not take the fault.. |
| */ |
| if (faulthandler_disabled() || !mm) |
| goto no_context; |
| |
| if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_USR) |
| 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 ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_USR) { |
| /* accessing the stack below the stack pointer is always a |
| * bug */ |
| if ((address & PAGE_MASK) + 2 * PAGE_SIZE < regs->sp) { |
| #if 0 |
| printk(KERN_WARNING |
| "[%d] ### Access below stack @%lx (sp=%lx)\n", |
| current->pid, address, regs->sp); |
| printk(KERN_WARNING |
| "vma [%08x - %08x]\n", |
| vma->vm_start, vma->vm_end); |
| show_registers(regs); |
| printk(KERN_WARNING |
| "[%d] ### Code: [%08lx]" |
| " %02x %02x %02x %02x %02x %02x %02x %02x\n", |
| current->pid, |
| regs->pc, |
| ((u8 *) regs->pc)[0], |
| ((u8 *) regs->pc)[1], |
| ((u8 *) regs->pc)[2], |
| ((u8 *) regs->pc)[3], |
| ((u8 *) regs->pc)[4], |
| ((u8 *) regs->pc)[5], |
| ((u8 *) regs->pc)[6], |
| ((u8 *) regs->pc)[7] |
| ); |
| #endif |
| 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: |
| info.si_code = SEGV_ACCERR; |
| switch (fault_code & (MMUFCR_xFC_PGINVAL|MMUFCR_xFC_TYPE)) { |
| default: /* 3: write, present */ |
| case MMUFCR_xFC_TYPE_WRITE: |
| #ifdef TEST_VERIFY_AREA |
| if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_SR) |
| printk(KERN_DEBUG "WP fault at %08lx\n", regs->pc); |
| #endif |
| /* write to absent page */ |
| case MMUFCR_xFC_PGINVAL | MMUFCR_xFC_TYPE_WRITE: |
| if (!(vma->vm_flags & VM_WRITE)) |
| goto bad_area; |
| flags |= FAULT_FLAG_WRITE; |
| break; |
| |
| /* read from protected page */ |
| case MMUFCR_xFC_TYPE_READ: |
| goto bad_area; |
| |
| /* read from absent page present */ |
| case MMUFCR_xFC_PGINVAL | MMUFCR_xFC_TYPE_READ: |
| if (!(vma->vm_flags & (VM_READ | VM_EXEC))) |
| goto bad_area; |
| break; |
| } |
| |
| /* |
| * 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(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) |
| current->maj_flt++; |
| else |
| current->min_flt++; |
| if (fault & VM_FAULT_RETRY) { |
| flags &= ~FAULT_FLAG_ALLOW_RETRY; |
| |
| /* 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); |
| |
| /* User mode accesses just cause a SIGSEGV */ |
| if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_USR) { |
| info.si_signo = SIGSEGV; |
| info.si_errno = 0; |
| /* info.si_code has been set above */ |
| info.si_addr = (void *)address; |
| force_sig_info(SIGSEGV, &info, tsk); |
| return; |
| } |
| |
| no_context: |
| /* Are we prepared to handle this kernel fault? */ |
| if (fixup_exception(regs)) |
| return; |
| |
| /* |
| * Oops. The kernel tried to access some bad page. We'll have to |
| * terminate things with extreme prejudice. |
| */ |
| |
| bust_spinlocks(1); |
| |
| 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); |
| printk(" printing pc:\n"); |
| printk(KERN_ALERT "%08lx\n", regs->pc); |
| |
| debugger_intercept(fault_code & 0x00010000 ? EXCEP_IAERROR : EXCEP_DAERROR, |
| SIGSEGV, SEGV_ACCERR, regs); |
| |
| page = PTBR; |
| page = ((unsigned long *) __va(page))[address >> 22]; |
| printk(KERN_ALERT "*pde = %08lx\n", page); |
| if (page & 1) { |
| page &= PAGE_MASK; |
| address &= 0x003ff000; |
| page = ((unsigned long *) __va(page))[address >> PAGE_SHIFT]; |
| printk(KERN_ALERT "*pte = %08lx\n", page); |
| } |
| |
| die("Oops", regs, fault_code); |
| do_exit(SIGKILL); |
| |
| /* |
| * 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 ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_USR) { |
| pagefault_out_of_memory(); |
| return; |
| } |
| goto no_context; |
| |
| do_sigbus: |
| up_read(&mm->mmap_sem); |
| |
| /* |
| * Send a sigbus, regardless of whether we were in kernel |
| * or user mode. |
| */ |
| info.si_signo = SIGBUS; |
| info.si_errno = 0; |
| info.si_code = BUS_ADRERR; |
| info.si_addr = (void *)address; |
| force_sig_info(SIGBUS, &info, tsk); |
| |
| /* Kernel mode? Handle exceptions or die */ |
| if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_SR) |
| goto no_context; |
| return; |
| |
| vmalloc_fault: |
| { |
| /* |
| * Synchronize this task's top level page-table |
| * with the 'reference' page table. |
| * |
| * Do _not_ use "tsk" here. We might be inside |
| * an interrupt in the middle of a task switch.. |
| */ |
| int index = pgd_index(address); |
| pgd_t *pgd, *pgd_k; |
| pud_t *pud, *pud_k; |
| pmd_t *pmd, *pmd_k; |
| pte_t *pte_k; |
| |
| pgd_k = init_mm.pgd + index; |
| |
| if (!pgd_present(*pgd_k)) |
| goto no_context; |
| |
| pud_k = pud_offset(pgd_k, address); |
| if (!pud_present(*pud_k)) |
| goto no_context; |
| |
| pmd_k = pmd_offset(pud_k, address); |
| if (!pmd_present(*pmd_k)) |
| goto no_context; |
| |
| pgd = (pgd_t *) PTBR + index; |
| pud = pud_offset(pgd, address); |
| pmd = pmd_offset(pud, address); |
| set_pmd(pmd, *pmd_k); |
| |
| pte_k = pte_offset_kernel(pmd_k, address); |
| if (!pte_present(*pte_k)) |
| goto no_context; |
| return; |
| } |
| } |