2d137c24e9
) From: Russell King <rmk+lkml@arm.linux.org.uk> ARM wasn't raising a SIGBUS with a siginfo structure. Fix __do_user_fault() to allow us to use it for SIGBUS conditions, and arrange for the sigbus path to use this. We need to prevent the siginfo code being called if we do not have a user space context to call it, so consolidate the "user_mode()" tests. Thanks to Ian Campbell who spotted this oversight. Signed-off-by: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
455 lines
10 KiB
C
455 lines
10 KiB
C
/*
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* linux/arch/arm/mm/fault.c
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*
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* Copyright (C) 1995 Linus Torvalds
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* Modifications for ARM processor (c) 1995-2004 Russell King
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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/config.h>
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#include <linux/module.h>
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#include <linux/signal.h>
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#include <linux/ptrace.h>
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#include <linux/mm.h>
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#include <linux/init.h>
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#include <asm/system.h>
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#include <asm/pgtable.h>
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#include <asm/tlbflush.h>
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#include <asm/uaccess.h>
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#include "fault.h"
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/*
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* This is useful to dump out the page tables associated with
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* 'addr' in mm 'mm'.
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*/
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void show_pte(struct mm_struct *mm, unsigned long addr)
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{
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pgd_t *pgd;
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if (!mm)
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mm = &init_mm;
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printk(KERN_ALERT "pgd = %p\n", mm->pgd);
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pgd = pgd_offset(mm, addr);
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printk(KERN_ALERT "[%08lx] *pgd=%08lx", addr, pgd_val(*pgd));
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do {
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pmd_t *pmd;
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pte_t *pte;
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if (pgd_none(*pgd))
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break;
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if (pgd_bad(*pgd)) {
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printk("(bad)");
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break;
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}
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pmd = pmd_offset(pgd, addr);
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#if PTRS_PER_PMD != 1
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printk(", *pmd=%08lx", pmd_val(*pmd));
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#endif
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if (pmd_none(*pmd))
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break;
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if (pmd_bad(*pmd)) {
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printk("(bad)");
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break;
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}
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#ifndef CONFIG_HIGHMEM
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/* We must not map this if we have highmem enabled */
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pte = pte_offset_map(pmd, addr);
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printk(", *pte=%08lx", pte_val(*pte));
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printk(", *ppte=%08lx", pte_val(pte[-PTRS_PER_PTE]));
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pte_unmap(pte);
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#endif
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} while(0);
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printk("\n");
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}
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/*
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* Oops. The kernel tried to access some page that wasn't present.
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*/
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static void
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__do_kernel_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
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struct pt_regs *regs)
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{
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/*
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* Are we prepared to handle this kernel fault?
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*/
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if (fixup_exception(regs))
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return;
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/*
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* No handler, we'll have to terminate things with extreme prejudice.
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*/
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bust_spinlocks(1);
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printk(KERN_ALERT
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"Unable to handle kernel %s at virtual address %08lx\n",
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(addr < PAGE_SIZE) ? "NULL pointer dereference" :
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"paging request", addr);
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show_pte(mm, addr);
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die("Oops", regs, fsr);
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bust_spinlocks(0);
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do_exit(SIGKILL);
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}
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/*
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* Something tried to access memory that isn't in our memory map..
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* User mode accesses just cause a SIGSEGV
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*/
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static void
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__do_user_fault(struct task_struct *tsk, unsigned long addr,
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unsigned int fsr, unsigned int sig, int code,
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struct pt_regs *regs)
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{
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struct siginfo si;
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#ifdef CONFIG_DEBUG_USER
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if (user_debug & UDBG_SEGV) {
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printk(KERN_DEBUG "%s: unhandled page fault (%d) at 0x%08lx, code 0x%03x\n",
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tsk->comm, sig, addr, fsr);
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show_pte(tsk->mm, addr);
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show_regs(regs);
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}
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#endif
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tsk->thread.address = addr;
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tsk->thread.error_code = fsr;
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tsk->thread.trap_no = 14;
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si.si_signo = sig;
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si.si_errno = 0;
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si.si_code = code;
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si.si_addr = (void __user *)addr;
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force_sig_info(sig, &si, tsk);
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}
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void
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do_bad_area(struct task_struct *tsk, struct mm_struct *mm, unsigned long addr,
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unsigned int fsr, struct pt_regs *regs)
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{
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/*
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* If we are in kernel mode at this point, we
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* have no context to handle this fault with.
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*/
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if (user_mode(regs))
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__do_user_fault(tsk, addr, fsr, SIGSEGV, SEGV_MAPERR, regs);
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else
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__do_kernel_fault(mm, addr, fsr, regs);
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}
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#define VM_FAULT_BADMAP (-20)
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#define VM_FAULT_BADACCESS (-21)
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static int
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__do_page_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
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struct task_struct *tsk)
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{
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struct vm_area_struct *vma;
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int fault, mask;
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vma = find_vma(mm, addr);
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fault = VM_FAULT_BADMAP;
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if (!vma)
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goto out;
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if (vma->vm_start > addr)
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goto check_stack;
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/*
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* Ok, we have a good vm_area for this
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* memory access, so we can handle it.
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*/
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good_area:
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if (fsr & (1 << 11)) /* write? */
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mask = VM_WRITE;
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else
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mask = VM_READ|VM_EXEC;
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fault = VM_FAULT_BADACCESS;
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if (!(vma->vm_flags & mask))
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goto out;
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/*
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* If for any reason at all we couldn't handle
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* the fault, make sure we exit gracefully rather
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* than endlessly redo the fault.
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*/
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survive:
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fault = handle_mm_fault(mm, vma, addr & PAGE_MASK, fsr & (1 << 11));
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/*
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* Handle the "normal" cases first - successful and sigbus
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*/
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switch (fault) {
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case VM_FAULT_MAJOR:
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tsk->maj_flt++;
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return fault;
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case VM_FAULT_MINOR:
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tsk->min_flt++;
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case VM_FAULT_SIGBUS:
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return fault;
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}
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if (tsk->pid != 1)
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goto out;
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/*
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* If we are out of memory for pid1, sleep for a while and retry
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*/
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up_read(&mm->mmap_sem);
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yield();
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down_read(&mm->mmap_sem);
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goto survive;
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check_stack:
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if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr))
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goto good_area;
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out:
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return fault;
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}
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static int
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do_page_fault(unsigned long addr, unsigned int fsr, 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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int fault, sig, code;
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tsk = current;
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mm = tsk->mm;
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/*
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* If we're in an interrupt or have no user
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* context, we must not take the fault..
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*/
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if (in_interrupt() || !mm)
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goto no_context;
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down_read(&mm->mmap_sem);
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fault = __do_page_fault(mm, addr, fsr, tsk);
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up_read(&mm->mmap_sem);
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/*
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* Handle the "normal" case first
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*/
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if (fault > 0)
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return 0;
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/*
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* If we are in kernel mode at this point, we
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* have no context to handle this fault with.
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*/
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if (!user_mode(regs))
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goto no_context;
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switch (fault) {
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case VM_FAULT_OOM:
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/*
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* We ran out of memory, or some other thing
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* happened to us that made us unable to handle
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* the page fault gracefully.
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*/
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printk("VM: killing process %s\n", tsk->comm);
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do_exit(SIGKILL);
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return 0;
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case 0:
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/*
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* We had some memory, but were unable to
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* successfully fix up this page fault.
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*/
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sig = SIGBUS;
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code = BUS_ADRERR;
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break;
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default:
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/*
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* Something tried to access memory that
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* isn't in our memory map..
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*/
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sig = SIGSEGV;
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code = fault == VM_FAULT_BADACCESS ?
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SEGV_ACCERR : SEGV_MAPERR;
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break;
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}
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__do_user_fault(tsk, addr, fsr, sig, code, regs);
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return 0;
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no_context:
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__do_kernel_fault(mm, addr, fsr, regs);
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return 0;
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}
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/*
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* First Level Translation Fault Handler
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*
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* We enter here because the first level page table doesn't contain
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* a valid entry for the address.
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*
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* If the address is in kernel space (>= TASK_SIZE), then we are
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* probably faulting in the vmalloc() area.
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*
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* If the init_task's first level page tables contains the relevant
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* entry, we copy the it to this task. If not, we send the process
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* a signal, fixup the exception, or oops the kernel.
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*
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* NOTE! We MUST NOT take any locks for this case. We may be in an
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* interrupt or a critical region, and should only copy the information
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* from the master page table, nothing more.
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*/
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static int
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do_translation_fault(unsigned long addr, unsigned int fsr,
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struct pt_regs *regs)
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{
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struct task_struct *tsk;
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unsigned int index;
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pgd_t *pgd, *pgd_k;
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pmd_t *pmd, *pmd_k;
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if (addr < TASK_SIZE)
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return do_page_fault(addr, fsr, regs);
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index = pgd_index(addr);
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/*
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* FIXME: CP15 C1 is write only on ARMv3 architectures.
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*/
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pgd = cpu_get_pgd() + index;
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pgd_k = init_mm.pgd + index;
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if (pgd_none(*pgd_k))
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goto bad_area;
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if (!pgd_present(*pgd))
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set_pgd(pgd, *pgd_k);
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pmd_k = pmd_offset(pgd_k, addr);
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pmd = pmd_offset(pgd, addr);
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if (pmd_none(*pmd_k))
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goto bad_area;
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copy_pmd(pmd, pmd_k);
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return 0;
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bad_area:
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tsk = current;
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do_bad_area(tsk, tsk->active_mm, addr, fsr, regs);
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return 0;
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}
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/*
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* Some section permission faults need to be handled gracefully.
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* They can happen due to a __{get,put}_user during an oops.
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*/
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static int
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do_sect_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
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{
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struct task_struct *tsk = current;
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do_bad_area(tsk, tsk->active_mm, addr, fsr, regs);
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return 0;
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}
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/*
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* This abort handler always returns "fault".
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*/
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static int
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do_bad(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
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{
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return 1;
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}
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static struct fsr_info {
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int (*fn)(unsigned long addr, unsigned int fsr, struct pt_regs *regs);
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int sig;
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const char *name;
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} fsr_info[] = {
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/*
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* The following are the standard ARMv3 and ARMv4 aborts. ARMv5
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* defines these to be "precise" aborts.
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*/
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{ do_bad, SIGSEGV, "vector exception" },
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{ do_bad, SIGILL, "alignment exception" },
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{ do_bad, SIGKILL, "terminal exception" },
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{ do_bad, SIGILL, "alignment exception" },
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{ do_bad, SIGBUS, "external abort on linefetch" },
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{ do_translation_fault, SIGSEGV, "section translation fault" },
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{ do_bad, SIGBUS, "external abort on linefetch" },
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{ do_page_fault, SIGSEGV, "page translation fault" },
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{ do_bad, SIGBUS, "external abort on non-linefetch" },
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{ do_bad, SIGSEGV, "section domain fault" },
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{ do_bad, SIGBUS, "external abort on non-linefetch" },
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{ do_bad, SIGSEGV, "page domain fault" },
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{ do_bad, SIGBUS, "external abort on translation" },
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{ do_sect_fault, SIGSEGV, "section permission fault" },
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{ do_bad, SIGBUS, "external abort on translation" },
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{ do_page_fault, SIGSEGV, "page permission fault" },
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/*
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* The following are "imprecise" aborts, which are signalled by bit
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* 10 of the FSR, and may not be recoverable. These are only
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* supported if the CPU abort handler supports bit 10.
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*/
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{ do_bad, SIGBUS, "unknown 16" },
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{ do_bad, SIGBUS, "unknown 17" },
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{ do_bad, SIGBUS, "unknown 18" },
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{ do_bad, SIGBUS, "unknown 19" },
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{ do_bad, SIGBUS, "lock abort" }, /* xscale */
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{ do_bad, SIGBUS, "unknown 21" },
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{ do_bad, SIGBUS, "imprecise external abort" }, /* xscale */
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{ do_bad, SIGBUS, "unknown 23" },
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{ do_bad, SIGBUS, "dcache parity error" }, /* xscale */
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{ do_bad, SIGBUS, "unknown 25" },
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{ do_bad, SIGBUS, "unknown 26" },
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{ do_bad, SIGBUS, "unknown 27" },
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{ do_bad, SIGBUS, "unknown 28" },
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{ do_bad, SIGBUS, "unknown 29" },
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{ do_bad, SIGBUS, "unknown 30" },
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{ do_bad, SIGBUS, "unknown 31" }
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};
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void __init
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hook_fault_code(int nr, int (*fn)(unsigned long, unsigned int, struct pt_regs *),
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int sig, const char *name)
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{
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if (nr >= 0 && nr < ARRAY_SIZE(fsr_info)) {
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fsr_info[nr].fn = fn;
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fsr_info[nr].sig = sig;
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fsr_info[nr].name = name;
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}
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}
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/*
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* Dispatch a data abort to the relevant handler.
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*/
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asmlinkage void
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do_DataAbort(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
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{
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const struct fsr_info *inf = fsr_info + (fsr & 15) + ((fsr & (1 << 10)) >> 6);
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if (!inf->fn(addr, fsr, regs))
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return;
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printk(KERN_ALERT "Unhandled fault: %s (0x%03x) at 0x%08lx\n",
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inf->name, fsr, addr);
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force_sig(inf->sig, current);
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show_pte(current->mm, addr);
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die_if_kernel("Oops", regs, 0);
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}
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asmlinkage void
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do_PrefetchAbort(unsigned long addr, struct pt_regs *regs)
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{
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do_translation_fault(addr, 0, regs);
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}
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