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394 lines
8.9 KiB
394 lines
8.9 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* fault.c: Page fault handlers for the Sparc. |
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* |
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* Copyright (C) 1995 David S. Miller ([email protected]) |
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* Copyright (C) 1996 Eddie C. Dost ([email protected]) |
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* Copyright (C) 1997 Jakub Jelinek ([email protected]) |
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*/ |
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#include <asm/head.h> |
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#include <linux/string.h> |
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#include <linux/types.h> |
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#include <linux/sched.h> |
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#include <linux/ptrace.h> |
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#include <linux/mman.h> |
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#include <linux/threads.h> |
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#include <linux/kernel.h> |
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#include <linux/signal.h> |
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#include <linux/mm.h> |
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#include <linux/smp.h> |
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#include <linux/perf_event.h> |
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#include <linux/interrupt.h> |
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#include <linux/kdebug.h> |
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#include <linux/uaccess.h> |
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#include <linux/extable.h> |
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#include <asm/page.h> |
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#include <asm/openprom.h> |
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#include <asm/oplib.h> |
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#include <asm/setup.h> |
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#include <asm/smp.h> |
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#include <asm/traps.h> |
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#include "mm_32.h" |
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int show_unhandled_signals = 1; |
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static void __noreturn unhandled_fault(unsigned long address, |
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struct task_struct *tsk, |
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struct pt_regs *regs) |
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{ |
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if ((unsigned long) address < PAGE_SIZE) { |
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printk(KERN_ALERT |
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"Unable to handle kernel NULL pointer dereference\n"); |
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} else { |
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printk(KERN_ALERT "Unable to handle kernel paging request at virtual address %08lx\n", |
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address); |
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} |
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printk(KERN_ALERT "tsk->{mm,active_mm}->context = %08lx\n", |
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(tsk->mm ? tsk->mm->context : tsk->active_mm->context)); |
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printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %08lx\n", |
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(tsk->mm ? (unsigned long) tsk->mm->pgd : |
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(unsigned long) tsk->active_mm->pgd)); |
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die_if_kernel("Oops", regs); |
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} |
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static inline void |
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show_signal_msg(struct pt_regs *regs, int sig, int code, |
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unsigned long address, struct task_struct *tsk) |
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{ |
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if (!unhandled_signal(tsk, sig)) |
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return; |
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if (!printk_ratelimit()) |
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return; |
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printk("%s%s[%d]: segfault at %lx ip %px (rpc %px) sp %px error %x", |
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task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG, |
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tsk->comm, task_pid_nr(tsk), address, |
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(void *)regs->pc, (void *)regs->u_regs[UREG_I7], |
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(void *)regs->u_regs[UREG_FP], code); |
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print_vma_addr(KERN_CONT " in ", regs->pc); |
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printk(KERN_CONT "\n"); |
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} |
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static void __do_fault_siginfo(int code, int sig, struct pt_regs *regs, |
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unsigned long addr) |
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{ |
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if (unlikely(show_unhandled_signals)) |
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show_signal_msg(regs, sig, code, |
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addr, current); |
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force_sig_fault(sig, code, (void __user *) addr, 0); |
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} |
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static unsigned long compute_si_addr(struct pt_regs *regs, int text_fault) |
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{ |
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unsigned int insn; |
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if (text_fault) |
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return regs->pc; |
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if (regs->psr & PSR_PS) |
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insn = *(unsigned int *) regs->pc; |
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else |
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__get_user(insn, (unsigned int *) regs->pc); |
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return safe_compute_effective_address(regs, insn); |
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} |
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static noinline void do_fault_siginfo(int code, int sig, struct pt_regs *regs, |
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int text_fault) |
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{ |
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unsigned long addr = compute_si_addr(regs, text_fault); |
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__do_fault_siginfo(code, sig, regs, addr); |
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} |
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asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write, |
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unsigned long address) |
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{ |
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struct vm_area_struct *vma; |
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struct task_struct *tsk = current; |
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struct mm_struct *mm = tsk->mm; |
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int from_user = !(regs->psr & PSR_PS); |
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int code; |
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vm_fault_t fault; |
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unsigned int flags = FAULT_FLAG_DEFAULT; |
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if (text_fault) |
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address = regs->pc; |
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/* |
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* We fault-in kernel-space virtual memory on-demand. The |
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* 'reference' page table is init_mm.pgd. |
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* |
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* NOTE! We MUST NOT take any locks for this case. We may |
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* be in an interrupt or a critical region, and should |
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* only copy the information from the master page table, |
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* nothing more. |
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*/ |
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code = SEGV_MAPERR; |
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if (address >= TASK_SIZE) |
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goto vmalloc_fault; |
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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 (pagefault_disabled() || !mm) |
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goto no_context; |
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perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); |
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retry: |
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mmap_read_lock(mm); |
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if (!from_user && address >= PAGE_OFFSET) |
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goto bad_area; |
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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 |
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* we can handle it.. |
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*/ |
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good_area: |
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code = SEGV_ACCERR; |
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if (write) { |
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if (!(vma->vm_flags & VM_WRITE)) |
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goto bad_area; |
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} else { |
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/* Allow reads even for write-only mappings */ |
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if (!(vma->vm_flags & (VM_READ | VM_EXEC))) |
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goto bad_area; |
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} |
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if (from_user) |
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flags |= FAULT_FLAG_USER; |
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if (write) |
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flags |= FAULT_FLAG_WRITE; |
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/* |
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* If for any reason at all we couldn't handle the fault, |
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* make sure we exit gracefully rather than endlessly redo |
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* the fault. |
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*/ |
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fault = handle_mm_fault(vma, address, flags, regs); |
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if (fault_signal_pending(fault, regs)) |
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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_RETRY) { |
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flags |= FAULT_FLAG_TRIED; |
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/* No need to mmap_read_unlock(mm) as we would |
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* have already released it in __lock_page_or_retry |
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* in 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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mmap_read_unlock(mm); |
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return; |
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/* |
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* Something tried to access memory that isn't in our memory map.. |
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* 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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mmap_read_unlock(mm); |
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bad_area_nosemaphore: |
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/* User mode accesses just cause a SIGSEGV */ |
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if (from_user) { |
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do_fault_siginfo(code, SIGSEGV, regs, text_fault); |
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return; |
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} |
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/* Is this in ex_table? */ |
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no_context: |
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if (!from_user) { |
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const struct exception_table_entry *entry; |
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entry = search_exception_tables(regs->pc); |
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#ifdef DEBUG_EXCEPTIONS |
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printk("Exception: PC<%08lx> faddr<%08lx>\n", |
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regs->pc, address); |
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printk("EX_TABLE: insn<%08lx> fixup<%08x>\n", |
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regs->pc, entry->fixup); |
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#endif |
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regs->pc = entry->fixup; |
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regs->npc = regs->pc + 4; |
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return; |
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} |
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unhandled_fault(address, tsk, regs); |
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do_exit(SIGKILL); |
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/* |
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* We ran out of memory, or some other thing happened to us that made |
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* us unable to handle the page fault gracefully. |
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*/ |
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out_of_memory: |
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mmap_read_unlock(mm); |
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if (from_user) { |
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pagefault_out_of_memory(); |
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return; |
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} |
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goto no_context; |
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do_sigbus: |
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mmap_read_unlock(mm); |
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do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, text_fault); |
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if (!from_user) |
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goto no_context; |
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vmalloc_fault: |
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{ |
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/* |
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* Synchronize this task's top level page-table |
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* with the 'reference' page table. |
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*/ |
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int offset = pgd_index(address); |
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pgd_t *pgd, *pgd_k; |
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p4d_t *p4d, *p4d_k; |
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pud_t *pud, *pud_k; |
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pmd_t *pmd, *pmd_k; |
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pgd = tsk->active_mm->pgd + offset; |
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pgd_k = init_mm.pgd + offset; |
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if (!pgd_present(*pgd)) { |
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if (!pgd_present(*pgd_k)) |
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goto bad_area_nosemaphore; |
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pgd_val(*pgd) = pgd_val(*pgd_k); |
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return; |
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} |
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p4d = p4d_offset(pgd, address); |
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pud = pud_offset(p4d, address); |
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pmd = pmd_offset(pud, address); |
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p4d_k = p4d_offset(pgd_k, address); |
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pud_k = pud_offset(p4d_k, address); |
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pmd_k = pmd_offset(pud_k, address); |
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if (pmd_present(*pmd) || !pmd_present(*pmd_k)) |
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goto bad_area_nosemaphore; |
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*pmd = *pmd_k; |
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return; |
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} |
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} |
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/* This always deals with user addresses. */ |
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static void force_user_fault(unsigned long address, int write) |
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{ |
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struct vm_area_struct *vma; |
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struct task_struct *tsk = current; |
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struct mm_struct *mm = tsk->mm; |
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unsigned int flags = FAULT_FLAG_USER; |
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int code; |
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code = SEGV_MAPERR; |
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mmap_read_lock(mm); |
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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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good_area: |
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code = SEGV_ACCERR; |
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if (write) { |
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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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} else { |
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if (!(vma->vm_flags & (VM_READ | VM_EXEC))) |
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goto bad_area; |
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} |
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switch (handle_mm_fault(vma, address, flags, NULL)) { |
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case VM_FAULT_SIGBUS: |
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case VM_FAULT_OOM: |
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goto do_sigbus; |
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} |
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mmap_read_unlock(mm); |
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return; |
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bad_area: |
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mmap_read_unlock(mm); |
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__do_fault_siginfo(code, SIGSEGV, tsk->thread.kregs, address); |
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return; |
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do_sigbus: |
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mmap_read_unlock(mm); |
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__do_fault_siginfo(BUS_ADRERR, SIGBUS, tsk->thread.kregs, address); |
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} |
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static void check_stack_aligned(unsigned long sp) |
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{ |
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if (sp & 0x7UL) |
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force_sig(SIGILL); |
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} |
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void window_overflow_fault(void) |
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{ |
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unsigned long sp; |
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sp = current_thread_info()->rwbuf_stkptrs[0]; |
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if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK)) |
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force_user_fault(sp + 0x38, 1); |
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force_user_fault(sp, 1); |
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check_stack_aligned(sp); |
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} |
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void window_underflow_fault(unsigned long sp) |
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{ |
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if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK)) |
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force_user_fault(sp + 0x38, 0); |
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force_user_fault(sp, 0); |
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check_stack_aligned(sp); |
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} |
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void window_ret_fault(struct pt_regs *regs) |
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{ |
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unsigned long sp; |
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sp = regs->u_regs[UREG_FP]; |
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if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK)) |
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force_user_fault(sp + 0x38, 0); |
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force_user_fault(sp, 0); |
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check_stack_aligned(sp); |
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}
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