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![Paul Gortmaker](/assets/img/avatar_default.png)
These files were only including module.h for exception table related functions. We've now separated that content out into its own file "extable.h" so now move over to that and avoid all the extra header content in module.h that we don't really need to compile these files. One uses "print_modules" so that prevents us removing module.h in that case, however. Cc: Haavard Skinnemoen <hskinnemoen@gmail.com> Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Acked-by: Hans-Christian Noren Egtvedt <egtvedt@samfundet.no>
268 lines
6.2 KiB
C
268 lines
6.2 KiB
C
/*
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* Copyright (C) 2004-2006 Atmel Corporation
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*
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* Based on linux/arch/sh/mm/fault.c:
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* Copyright (C) 1999 Niibe Yutaka
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/mm.h>
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#include <linux/extable.h>
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#include <linux/pagemap.h>
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#include <linux/kdebug.h>
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#include <linux/kprobes.h>
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#include <linux/uaccess.h>
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#include <asm/mmu_context.h>
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#include <asm/sysreg.h>
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#include <asm/tlb.h>
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#ifdef CONFIG_KPROBES
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static inline int notify_page_fault(struct pt_regs *regs, int trap)
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{
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int ret = 0;
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if (!user_mode(regs)) {
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if (kprobe_running() && kprobe_fault_handler(regs, trap))
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ret = 1;
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}
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return ret;
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}
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#else
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static inline int notify_page_fault(struct pt_regs *regs, int trap)
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{
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return 0;
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}
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#endif
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int exception_trace = 1;
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/*
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* This routine handles page faults. It determines the address and the
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* problem, and then passes it off to one of the appropriate routines.
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*
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* ecr is the Exception Cause Register. Possible values are:
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* 6: Protection fault (instruction access)
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* 15: Protection fault (read access)
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* 16: Protection fault (write access)
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* 20: Page not found (instruction access)
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* 24: Page not found (read access)
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* 28: Page not found (write access)
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*/
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asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs)
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{
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struct task_struct *tsk;
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struct mm_struct *mm;
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struct vm_area_struct *vma;
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const struct exception_table_entry *fixup;
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unsigned long address;
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unsigned long page;
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long signr;
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int code;
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int fault;
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unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
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if (notify_page_fault(regs, ecr))
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return;
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address = sysreg_read(TLBEAR);
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tsk = current;
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mm = tsk->mm;
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signr = SIGSEGV;
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code = SEGV_MAPERR;
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/*
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* If we're in an interrupt or have no user context, we must
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* not take the fault...
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*/
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if (faulthandler_disabled() || !mm || regs->sr & SYSREG_BIT(GM))
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goto no_context;
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local_irq_enable();
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if (user_mode(regs))
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flags |= FAULT_FLAG_USER;
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retry:
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down_read(&mm->mmap_sem);
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vma = find_vma(mm, address);
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if (!vma)
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goto bad_area;
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if (vma->vm_start <= address)
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goto good_area;
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if (!(vma->vm_flags & VM_GROWSDOWN))
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goto bad_area;
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if (expand_stack(vma, address))
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goto bad_area;
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/*
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* Ok, we have a good vm_area for this memory access, so we
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* can handle it...
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*/
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good_area:
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code = SEGV_ACCERR;
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switch (ecr) {
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case ECR_PROTECTION_X:
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case ECR_TLB_MISS_X:
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if (!(vma->vm_flags & VM_EXEC))
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goto bad_area;
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break;
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case ECR_PROTECTION_R:
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case ECR_TLB_MISS_R:
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if (!(vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC)))
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goto bad_area;
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break;
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case ECR_PROTECTION_W:
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case ECR_TLB_MISS_W:
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if (!(vma->vm_flags & VM_WRITE))
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goto bad_area;
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flags |= FAULT_FLAG_WRITE;
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break;
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default:
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panic("Unhandled case %lu in do_page_fault!", ecr);
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}
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/*
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* If for any reason at all we couldn't handle the fault, make
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* sure we exit gracefully rather than endlessly redo the
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* fault.
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*/
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fault = handle_mm_fault(vma, address, flags);
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if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
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return;
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if (unlikely(fault & VM_FAULT_ERROR)) {
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if (fault & VM_FAULT_OOM)
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goto out_of_memory;
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else if (fault & VM_FAULT_SIGSEGV)
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goto bad_area;
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else if (fault & VM_FAULT_SIGBUS)
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goto do_sigbus;
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BUG();
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}
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if (flags & FAULT_FLAG_ALLOW_RETRY) {
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if (fault & VM_FAULT_MAJOR)
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tsk->maj_flt++;
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else
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tsk->min_flt++;
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if (fault & VM_FAULT_RETRY) {
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flags &= ~FAULT_FLAG_ALLOW_RETRY;
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flags |= FAULT_FLAG_TRIED;
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/*
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* No need to up_read(&mm->mmap_sem) as we would have
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* already released it in __lock_page_or_retry() in
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* mm/filemap.c.
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*/
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goto retry;
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}
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}
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up_read(&mm->mmap_sem);
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return;
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/*
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* Something tried to access memory that isn't in our memory
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* map. Fix it, but check if it's kernel or user first...
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*/
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bad_area:
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up_read(&mm->mmap_sem);
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if (user_mode(regs)) {
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if (exception_trace && printk_ratelimit())
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printk("%s%s[%d]: segfault at %08lx pc %08lx "
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"sp %08lx ecr %lu\n",
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is_global_init(tsk) ? KERN_EMERG : KERN_INFO,
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tsk->comm, tsk->pid, address, regs->pc,
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regs->sp, ecr);
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_exception(SIGSEGV, regs, code, address);
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return;
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}
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no_context:
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/* Are we prepared to handle this kernel fault? */
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fixup = search_exception_tables(regs->pc);
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if (fixup) {
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regs->pc = fixup->fixup;
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return;
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}
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/*
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* Oops. The kernel tried to access some bad page. We'll have
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* to terminate things with extreme prejudice.
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*/
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if (address < PAGE_SIZE)
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printk(KERN_ALERT
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"Unable to handle kernel NULL pointer dereference");
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else
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printk(KERN_ALERT
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"Unable to handle kernel paging request");
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printk(" at virtual address %08lx\n", address);
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page = sysreg_read(PTBR);
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printk(KERN_ALERT "ptbr = %08lx", page);
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if (address >= TASK_SIZE)
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page = (unsigned long)swapper_pg_dir;
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if (page) {
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page = ((unsigned long *)page)[address >> 22];
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printk(" pgd = %08lx", page);
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if (page & _PAGE_PRESENT) {
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page &= PAGE_MASK;
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address &= 0x003ff000;
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page = ((unsigned long *)__va(page))[address >> PAGE_SHIFT];
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printk(" pte = %08lx", page);
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}
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}
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printk("\n");
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die("Kernel access of bad area", regs, signr);
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return;
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/*
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* We ran out of memory, or some other thing happened to us
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* that made us unable to handle the page fault gracefully.
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*/
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out_of_memory:
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up_read(&mm->mmap_sem);
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if (!user_mode(regs))
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goto no_context;
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pagefault_out_of_memory();
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return;
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do_sigbus:
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up_read(&mm->mmap_sem);
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/* Kernel mode? Handle exceptions or die */
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signr = SIGBUS;
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code = BUS_ADRERR;
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if (!user_mode(regs))
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goto no_context;
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if (exception_trace)
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printk("%s%s[%d]: bus error at %08lx pc %08lx "
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"sp %08lx ecr %lu\n",
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is_global_init(tsk) ? KERN_EMERG : KERN_INFO,
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tsk->comm, tsk->pid, address, regs->pc,
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regs->sp, ecr);
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_exception(SIGBUS, regs, BUS_ADRERR, address);
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}
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asmlinkage void do_bus_error(unsigned long addr, int write_access,
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struct pt_regs *regs)
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{
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printk(KERN_ALERT
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"Bus error at physical address 0x%08lx (%s access)\n",
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addr, write_access ? "write" : "read");
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printk(KERN_INFO "DTLB dump:\n");
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dump_dtlb();
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die("Bus Error", regs, SIGKILL);
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}
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