59f67e16e6
This function is only called from arch/arm64/mm/fault.c. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
531 lines
15 KiB
C
531 lines
15 KiB
C
/*
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* Based on arch/arm/mm/fault.c
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*
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* Copyright (C) 1995 Linus Torvalds
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* Copyright (C) 1995-2004 Russell King
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* Copyright (C) 2012 ARM Ltd.
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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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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/module.h>
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#include <linux/signal.h>
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#include <linux/mm.h>
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#include <linux/hardirq.h>
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#include <linux/init.h>
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#include <linux/kprobes.h>
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#include <linux/uaccess.h>
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#include <linux/page-flags.h>
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#include <linux/sched.h>
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#include <linux/highmem.h>
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#include <linux/perf_event.h>
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#include <asm/exception.h>
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#include <asm/debug-monitors.h>
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#include <asm/system_misc.h>
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#include <asm/pgtable.h>
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#include <asm/tlbflush.h>
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static const char *fault_name(unsigned int esr);
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/*
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* Dump out the page tables associated with '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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pr_alert("pgd = %p\n", mm->pgd);
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pgd = pgd_offset(mm, addr);
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pr_alert("[%08lx] *pgd=%016llx", addr, pgd_val(*pgd));
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do {
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pud_t *pud;
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pmd_t *pmd;
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pte_t *pte;
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if (pgd_none(*pgd) || pgd_bad(*pgd))
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break;
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pud = pud_offset(pgd, addr);
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if (pud_none(*pud) || pud_bad(*pud))
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break;
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pmd = pmd_offset(pud, addr);
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printk(", *pmd=%016llx", pmd_val(*pmd));
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if (pmd_none(*pmd) || pmd_bad(*pmd))
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break;
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pte = pte_offset_map(pmd, addr);
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printk(", *pte=%016llx", pte_val(*pte));
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pte_unmap(pte);
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} while(0);
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printk("\n");
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}
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/*
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* The kernel tried to access some page that wasn't present.
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*/
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static void __do_kernel_fault(struct mm_struct *mm, unsigned long addr,
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unsigned int esr, 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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pr_alert("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, esr);
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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. User mode
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* accesses just cause a SIGSEGV
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*/
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static void __do_user_fault(struct task_struct *tsk, unsigned long addr,
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unsigned int esr, 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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if (show_unhandled_signals && unhandled_signal(tsk, sig) &&
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printk_ratelimit()) {
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pr_info("%s[%d]: unhandled %s (%d) at 0x%08lx, esr 0x%03x\n",
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tsk->comm, task_pid_nr(tsk), fault_name(esr), sig,
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addr, esr);
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show_pte(tsk->mm, addr);
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show_regs(regs);
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}
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tsk->thread.fault_address = addr;
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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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static void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *regs)
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{
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struct task_struct *tsk = current;
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struct mm_struct *mm = tsk->active_mm;
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/*
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* If we are in kernel mode at this point, we have no context to
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* 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, esr, SIGSEGV, SEGV_MAPERR, regs);
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else
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__do_kernel_fault(mm, addr, esr, regs);
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}
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#define VM_FAULT_BADMAP 0x010000
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#define VM_FAULT_BADACCESS 0x020000
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#define ESR_WRITE (1 << 6)
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#define ESR_CM (1 << 8)
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#define ESR_LNX_EXEC (1 << 24)
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static int __do_page_fault(struct mm_struct *mm, unsigned long addr,
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unsigned int mm_flags, unsigned long vm_flags,
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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;
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vma = find_vma(mm, addr);
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fault = VM_FAULT_BADMAP;
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if (unlikely(!vma))
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goto out;
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if (unlikely(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 memory access, so we can handle
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* it.
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*/
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good_area:
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/*
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* Check that the permissions on the VMA allow for the fault which
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* occurred. If we encountered a write or exec fault, we must have
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* appropriate permissions, otherwise we allow any permission.
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*/
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if (!(vma->vm_flags & vm_flags)) {
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fault = VM_FAULT_BADACCESS;
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goto out;
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}
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return handle_mm_fault(mm, vma, addr & PAGE_MASK, mm_flags);
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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 __kprobes do_page_fault(unsigned long addr, unsigned int esr,
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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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unsigned long vm_flags = VM_READ | VM_WRITE | VM_EXEC;
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unsigned int mm_flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
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tsk = current;
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mm = tsk->mm;
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/* Enable interrupts if they were enabled in the parent context. */
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if (interrupts_enabled(regs))
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local_irq_enable();
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/*
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* If we're in an interrupt or have no user context, we must not take
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* the fault.
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*/
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if (in_atomic() || !mm)
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goto no_context;
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if (user_mode(regs))
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mm_flags |= FAULT_FLAG_USER;
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if (esr & ESR_LNX_EXEC) {
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vm_flags = VM_EXEC;
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} else if ((esr & ESR_WRITE) && !(esr & ESR_CM)) {
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vm_flags = VM_WRITE;
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mm_flags |= FAULT_FLAG_WRITE;
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}
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/*
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* As per x86, we may deadlock here. However, since the kernel only
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* validly references user space from well defined areas of the code,
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* we can bug out early if this is from code which shouldn't.
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*/
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if (!down_read_trylock(&mm->mmap_sem)) {
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if (!user_mode(regs) && !search_exception_tables(regs->pc))
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goto no_context;
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retry:
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down_read(&mm->mmap_sem);
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} else {
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/*
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* The above down_read_trylock() might have succeeded in which
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* case, we'll have missed the might_sleep() from down_read().
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*/
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might_sleep();
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#ifdef CONFIG_DEBUG_VM
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if (!user_mode(regs) && !search_exception_tables(regs->pc))
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goto no_context;
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#endif
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}
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fault = __do_page_fault(mm, addr, mm_flags, vm_flags, tsk);
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/*
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* If we need to retry but a fatal signal is pending, handle the
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* signal first. We do not need to release the mmap_sem because it
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* would already be released in __lock_page_or_retry in mm/filemap.c.
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*/
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if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
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return 0;
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/*
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* Major/minor page fault accounting is only done on the initial
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* attempt. If we go through a retry, it is extremely likely that the
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* page will be found in page cache at that point.
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*/
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perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);
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if (mm_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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perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs,
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addr);
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} else {
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tsk->min_flt++;
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perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs,
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addr);
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}
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if (fault & VM_FAULT_RETRY) {
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/*
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* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk of
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* starvation.
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*/
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mm_flags &= ~FAULT_FLAG_ALLOW_RETRY;
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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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/*
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* Handle the "normal" case first - VM_FAULT_MAJOR / VM_FAULT_MINOR
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*/
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if (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP |
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VM_FAULT_BADACCESS))))
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return 0;
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/*
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* If we are in kernel mode at this point, we have no context to
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* 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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if (fault & VM_FAULT_OOM) {
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/*
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* We ran out of memory, call the OOM killer, and return to
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* userspace (which will retry the fault, or kill us if we got
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* oom-killed).
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*/
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pagefault_out_of_memory();
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return 0;
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}
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if (fault & VM_FAULT_SIGBUS) {
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/*
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* We had some memory, but were unable to successfully fix up
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* this page fault.
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*/
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sig = SIGBUS;
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code = BUS_ADRERR;
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} else {
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/*
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* Something tried to access memory that isn't in our memory
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* 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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}
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__do_user_fault(tsk, addr, esr, sig, code, regs);
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return 0;
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no_context:
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__do_kernel_fault(mm, addr, esr, 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 a valid
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* entry for the address.
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*
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* If the address is in kernel space (>= TASK_SIZE), then we are probably
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* 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 entry, we
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* copy the it to this task. If not, we send the process a signal, fixup the
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* 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 interrupt
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* or a critical region, and should only copy the information from the master
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* page table, nothing more.
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*/
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static int __kprobes do_translation_fault(unsigned long addr,
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unsigned int esr,
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struct pt_regs *regs)
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{
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if (addr < TASK_SIZE)
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return do_page_fault(addr, esr, regs);
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do_bad_area(addr, esr, 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 do_bad(unsigned long addr, unsigned int esr, struct pt_regs *regs)
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{
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return 1;
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}
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static struct fault_info {
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int (*fn)(unsigned long addr, unsigned int esr, struct pt_regs *regs);
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int sig;
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int code;
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const char *name;
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} fault_info[] = {
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{ do_bad, SIGBUS, 0, "ttbr address size fault" },
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{ do_bad, SIGBUS, 0, "level 1 address size fault" },
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{ do_bad, SIGBUS, 0, "level 2 address size fault" },
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{ do_bad, SIGBUS, 0, "level 3 address size fault" },
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{ do_translation_fault, SIGSEGV, SEGV_MAPERR, "input address range fault" },
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{ do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 1 translation fault" },
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{ do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 2 translation fault" },
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{ do_page_fault, SIGSEGV, SEGV_MAPERR, "level 3 translation fault" },
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{ do_bad, SIGBUS, 0, "reserved access flag fault" },
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{ do_page_fault, SIGSEGV, SEGV_ACCERR, "level 1 access flag fault" },
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{ do_page_fault, SIGSEGV, SEGV_ACCERR, "level 2 access flag fault" },
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{ do_page_fault, SIGSEGV, SEGV_ACCERR, "level 3 access flag fault" },
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{ do_bad, SIGBUS, 0, "reserved permission fault" },
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{ do_page_fault, SIGSEGV, SEGV_ACCERR, "level 1 permission fault" },
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{ do_page_fault, SIGSEGV, SEGV_ACCERR, "level 2 permission fault" },
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{ do_page_fault, SIGSEGV, SEGV_ACCERR, "level 3 permission fault" },
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{ do_bad, SIGBUS, 0, "synchronous external abort" },
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{ do_bad, SIGBUS, 0, "asynchronous external abort" },
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{ do_bad, SIGBUS, 0, "unknown 18" },
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{ do_bad, SIGBUS, 0, "unknown 19" },
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{ do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" },
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{ do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" },
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{ do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" },
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{ do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" },
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{ do_bad, SIGBUS, 0, "synchronous parity error" },
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{ do_bad, SIGBUS, 0, "asynchronous parity error" },
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{ do_bad, SIGBUS, 0, "unknown 26" },
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{ do_bad, SIGBUS, 0, "unknown 27" },
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{ do_bad, SIGBUS, 0, "synchronous parity error (translation table walk" },
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{ do_bad, SIGBUS, 0, "synchronous parity error (translation table walk" },
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{ do_bad, SIGBUS, 0, "synchronous parity error (translation table walk" },
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{ do_bad, SIGBUS, 0, "synchronous parity error (translation table walk" },
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{ do_bad, SIGBUS, 0, "unknown 32" },
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{ do_bad, SIGBUS, BUS_ADRALN, "alignment fault" },
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{ do_bad, SIGBUS, 0, "debug event" },
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{ do_bad, SIGBUS, 0, "unknown 35" },
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{ do_bad, SIGBUS, 0, "unknown 36" },
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{ do_bad, SIGBUS, 0, "unknown 37" },
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{ do_bad, SIGBUS, 0, "unknown 38" },
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{ do_bad, SIGBUS, 0, "unknown 39" },
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{ do_bad, SIGBUS, 0, "unknown 40" },
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{ do_bad, SIGBUS, 0, "unknown 41" },
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{ do_bad, SIGBUS, 0, "unknown 42" },
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{ do_bad, SIGBUS, 0, "unknown 43" },
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{ do_bad, SIGBUS, 0, "unknown 44" },
|
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{ do_bad, SIGBUS, 0, "unknown 45" },
|
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{ do_bad, SIGBUS, 0, "unknown 46" },
|
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{ do_bad, SIGBUS, 0, "unknown 47" },
|
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{ do_bad, SIGBUS, 0, "unknown 48" },
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{ do_bad, SIGBUS, 0, "unknown 49" },
|
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{ do_bad, SIGBUS, 0, "unknown 50" },
|
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{ do_bad, SIGBUS, 0, "unknown 51" },
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{ do_bad, SIGBUS, 0, "implementation fault (lockdown abort)" },
|
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{ do_bad, SIGBUS, 0, "unknown 53" },
|
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{ do_bad, SIGBUS, 0, "unknown 54" },
|
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{ do_bad, SIGBUS, 0, "unknown 55" },
|
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{ do_bad, SIGBUS, 0, "unknown 56" },
|
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{ do_bad, SIGBUS, 0, "unknown 57" },
|
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{ do_bad, SIGBUS, 0, "implementation fault (coprocessor abort)" },
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{ do_bad, SIGBUS, 0, "unknown 59" },
|
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{ do_bad, SIGBUS, 0, "unknown 60" },
|
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{ do_bad, SIGBUS, 0, "unknown 61" },
|
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{ do_bad, SIGBUS, 0, "unknown 62" },
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{ do_bad, SIGBUS, 0, "unknown 63" },
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};
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|
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static const char *fault_name(unsigned int esr)
|
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{
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const struct fault_info *inf = fault_info + (esr & 63);
|
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return inf->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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asmlinkage void __exception do_mem_abort(unsigned long addr, unsigned int esr,
|
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struct pt_regs *regs)
|
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{
|
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const struct fault_info *inf = fault_info + (esr & 63);
|
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struct siginfo info;
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|
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if (!inf->fn(addr, esr, regs))
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return;
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|
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pr_alert("Unhandled fault: %s (0x%08x) at 0x%016lx\n",
|
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inf->name, esr, addr);
|
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|
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info.si_signo = inf->sig;
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info.si_errno = 0;
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info.si_code = inf->code;
|
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info.si_addr = (void __user *)addr;
|
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arm64_notify_die("", regs, &info, esr);
|
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}
|
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|
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/*
|
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* Handle stack alignment exceptions.
|
|
*/
|
|
asmlinkage void __exception do_sp_pc_abort(unsigned long addr,
|
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unsigned int esr,
|
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struct pt_regs *regs)
|
|
{
|
|
struct siginfo info;
|
|
|
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info.si_signo = SIGBUS;
|
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info.si_errno = 0;
|
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info.si_code = BUS_ADRALN;
|
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info.si_addr = (void __user *)addr;
|
|
arm64_notify_die("", regs, &info, esr);
|
|
}
|
|
|
|
static struct fault_info debug_fault_info[] = {
|
|
{ do_bad, SIGTRAP, TRAP_HWBKPT, "hardware breakpoint" },
|
|
{ do_bad, SIGTRAP, TRAP_HWBKPT, "hardware single-step" },
|
|
{ do_bad, SIGTRAP, TRAP_HWBKPT, "hardware watchpoint" },
|
|
{ do_bad, SIGBUS, 0, "unknown 3" },
|
|
{ do_bad, SIGTRAP, TRAP_BRKPT, "aarch32 BKPT" },
|
|
{ do_bad, SIGTRAP, 0, "aarch32 vector catch" },
|
|
{ do_bad, SIGTRAP, TRAP_BRKPT, "aarch64 BRK" },
|
|
{ do_bad, SIGBUS, 0, "unknown 7" },
|
|
};
|
|
|
|
void __init hook_debug_fault_code(int nr,
|
|
int (*fn)(unsigned long, unsigned int, struct pt_regs *),
|
|
int sig, int code, const char *name)
|
|
{
|
|
BUG_ON(nr < 0 || nr >= ARRAY_SIZE(debug_fault_info));
|
|
|
|
debug_fault_info[nr].fn = fn;
|
|
debug_fault_info[nr].sig = sig;
|
|
debug_fault_info[nr].code = code;
|
|
debug_fault_info[nr].name = name;
|
|
}
|
|
|
|
asmlinkage int __exception do_debug_exception(unsigned long addr,
|
|
unsigned int esr,
|
|
struct pt_regs *regs)
|
|
{
|
|
const struct fault_info *inf = debug_fault_info + DBG_ESR_EVT(esr);
|
|
struct siginfo info;
|
|
|
|
if (!inf->fn(addr, esr, regs))
|
|
return 1;
|
|
|
|
pr_alert("Unhandled debug exception: %s (0x%08x) at 0x%016lx\n",
|
|
inf->name, esr, addr);
|
|
|
|
info.si_signo = inf->sig;
|
|
info.si_errno = 0;
|
|
info.si_code = inf->code;
|
|
info.si_addr = (void __user *)addr;
|
|
arm64_notify_die("", regs, &info, esr);
|
|
|
|
return 0;
|
|
}
|