diff options
Diffstat (limited to 'arch/mn10300/mm/fault.c')
| -rw-r--r-- | arch/mn10300/mm/fault.c | 414 |
1 files changed, 414 insertions, 0 deletions
diff --git a/arch/mn10300/mm/fault.c b/arch/mn10300/mm/fault.c new file mode 100644 index 000000000..0c2cc5d39 --- /dev/null +++ b/arch/mn10300/mm/fault.c @@ -0,0 +1,414 @@ +/* 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 <asm/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 ]------------\n"); + 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 (in_atomic() || !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(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) + 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; + } +} |