+++ /dev/null
-// SPDX-License-Identifier: GPL-2.0
-/*
- * MMU fault handling support.
- *
- * Copyright (C) 1998-2002 Hewlett-Packard Co
- * David Mosberger-Tang <davidm@hpl.hp.com>
- */
-#include <linux/sched/signal.h>
-#include <linux/kernel.h>
-#include <linux/mm.h>
-#include <linux/extable.h>
-#include <linux/interrupt.h>
-#include <linux/kprobes.h>
-#include <linux/kdebug.h>
-#include <linux/prefetch.h>
-#include <linux/uaccess.h>
-#include <linux/perf_event.h>
-
-#include <asm/processor.h>
-#include <asm/exception.h>
-
-extern int die(char *, struct pt_regs *, long);
-
-/*
- * Return TRUE if ADDRESS points at a page in the kernel's mapped segment
- * (inside region 5, on ia64) and that page is present.
- */
-static int
-mapped_kernel_page_is_present (unsigned long address)
-{
- pgd_t *pgd;
- p4d_t *p4d;
- pud_t *pud;
- pmd_t *pmd;
- pte_t *ptep, pte;
-
- pgd = pgd_offset_k(address);
- if (pgd_none(*pgd) || pgd_bad(*pgd))
- return 0;
-
- p4d = p4d_offset(pgd, address);
- if (p4d_none(*p4d) || p4d_bad(*p4d))
- return 0;
-
- pud = pud_offset(p4d, address);
- if (pud_none(*pud) || pud_bad(*pud))
- return 0;
-
- pmd = pmd_offset(pud, address);
- if (pmd_none(*pmd) || pmd_bad(*pmd))
- return 0;
-
- ptep = pte_offset_kernel(pmd, address);
- if (!ptep)
- return 0;
-
- pte = *ptep;
- return pte_present(pte);
-}
-
-# define VM_READ_BIT 0
-# define VM_WRITE_BIT 1
-# define VM_EXEC_BIT 2
-
-void __kprobes
-ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *regs)
-{
- int signal = SIGSEGV, code = SEGV_MAPERR;
- struct vm_area_struct *vma, *prev_vma;
- struct mm_struct *mm = current->mm;
- unsigned long mask;
- vm_fault_t fault;
- unsigned int flags = FAULT_FLAG_DEFAULT;
-
- mask = ((((isr >> IA64_ISR_X_BIT) & 1UL) << VM_EXEC_BIT)
- | (((isr >> IA64_ISR_W_BIT) & 1UL) << VM_WRITE_BIT));
-
- /* mmap_lock is performance critical.... */
- prefetchw(&mm->mmap_lock);
-
- /*
- * If we're in an interrupt or have no user context, we must not take the fault..
- */
- if (faulthandler_disabled() || !mm)
- goto no_context;
-
- /*
- * This is to handle the kprobes on user space access instructions
- */
- if (kprobe_page_fault(regs, TRAP_BRKPT))
- return;
-
- if (user_mode(regs))
- flags |= FAULT_FLAG_USER;
- if (mask & VM_WRITE)
- flags |= FAULT_FLAG_WRITE;
-
- perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
-retry:
- mmap_read_lock(mm);
-
- vma = find_vma_prev(mm, address, &prev_vma);
- if (!vma && !prev_vma )
- goto bad_area;
-
- /*
- * find_vma_prev() returns vma such that address < vma->vm_end or NULL
- *
- * May find no vma, but could be that the last vm area is the
- * register backing store that needs to expand upwards, in
- * this case vma will be null, but prev_vma will ne non-null
- */
- if (( !vma && prev_vma ) || (address < vma->vm_start) ) {
- vma = expand_stack(mm, address);
- if (!vma)
- goto bad_area_nosemaphore;
- }
-
- code = SEGV_ACCERR;
-
- /* OK, we've got a good vm_area for this memory area. Check the access permissions: */
-
-# if (((1 << VM_READ_BIT) != VM_READ || (1 << VM_WRITE_BIT) != VM_WRITE) \
- || (1 << VM_EXEC_BIT) != VM_EXEC)
-# error File is out of sync with <linux/mm.h>. Please update.
-# endif
-
- if (((isr >> IA64_ISR_R_BIT) & 1UL) && (!(vma->vm_flags & (VM_READ | VM_WRITE))))
- goto bad_area;
-
- if ((vma->vm_flags & mask) != mask)
- goto bad_area;
-
- /*
- * If for any reason at all we couldn't handle the fault, make
- * sure we exit gracefully rather than endlessly redo the
- * fault.
- */
- fault = handle_mm_fault(vma, address, flags, regs);
-
- if (fault_signal_pending(fault, regs)) {
- if (!user_mode(regs))
- goto no_context;
- return;
- }
-
- /* The fault is fully completed (including releasing mmap lock) */
- if (fault & VM_FAULT_COMPLETED)
- return;
-
- if (unlikely(fault & VM_FAULT_ERROR)) {
- /*
- * We ran out of memory, or some other thing happened
- * to us that made us unable to handle the page fault
- * gracefully.
- */
- if (fault & VM_FAULT_OOM) {
- goto out_of_memory;
- } else if (fault & VM_FAULT_SIGSEGV) {
- goto bad_area;
- } else if (fault & VM_FAULT_SIGBUS) {
- signal = SIGBUS;
- goto bad_area;
- }
- BUG();
- }
-
- if (fault & VM_FAULT_RETRY) {
- flags |= FAULT_FLAG_TRIED;
-
- /* No need to mmap_read_unlock(mm) as we would
- * have already released it in __lock_page_or_retry
- * in mm/filemap.c.
- */
-
- goto retry;
- }
-
- mmap_read_unlock(mm);
- return;
-
- bad_area:
- mmap_read_unlock(mm);
- bad_area_nosemaphore:
- if ((isr & IA64_ISR_SP)
- || ((isr & IA64_ISR_NA) && (isr & IA64_ISR_CODE_MASK) == IA64_ISR_CODE_LFETCH))
- {
- /*
- * This fault was due to a speculative load or lfetch.fault, set the "ed"
- * bit in the psr to ensure forward progress. (Target register will get a
- * NaT for ld.s, lfetch will be canceled.)
- */
- ia64_psr(regs)->ed = 1;
- return;
- }
- if (user_mode(regs)) {
- force_sig_fault(signal, code, (void __user *) address,
- 0, __ISR_VALID, isr);
- return;
- }
-
- no_context:
- if ((isr & IA64_ISR_SP)
- || ((isr & IA64_ISR_NA) && (isr & IA64_ISR_CODE_MASK) == IA64_ISR_CODE_LFETCH))
- {
- /*
- * This fault was due to a speculative load or lfetch.fault, set the "ed"
- * bit in the psr to ensure forward progress. (Target register will get a
- * NaT for ld.s, lfetch will be canceled.)
- */
- ia64_psr(regs)->ed = 1;
- return;
- }
-
- /*
- * Since we have no vma's for region 5, we might get here even if the address is
- * valid, due to the VHPT walker inserting a non present translation that becomes
- * stale. If that happens, the non present fault handler already purged the stale
- * translation, which fixed the problem. So, we check to see if the translation is
- * valid, and return if it is.
- */
- if (REGION_NUMBER(address) == 5 && mapped_kernel_page_is_present(address))
- return;
-
- if (ia64_done_with_exception(regs))
- return;
-
- /*
- * Oops. The kernel tried to access some bad page. We'll have to terminate things
- * with extreme prejudice.
- */
- bust_spinlocks(1);
-
- if (address < PAGE_SIZE)
- printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference (address %016lx)\n", address);
- else
- printk(KERN_ALERT "Unable to handle kernel paging request at "
- "virtual address %016lx\n", address);
- if (die("Oops", regs, isr))
- regs = NULL;
- bust_spinlocks(0);
- if (regs)
- make_task_dead(SIGKILL);
- return;
-
- out_of_memory:
- mmap_read_unlock(mm);
- if (!user_mode(regs))
- goto no_context;
- pagefault_out_of_memory();
-}
projects / linux-2.6-block.git / blobdiff