diff options
Diffstat (limited to 'arch/cris/mm/fault.c')
| -rw-r--r-- | arch/cris/mm/fault.c | 390 |
1 files changed, 0 insertions, 390 deletions
diff --git a/arch/cris/mm/fault.c b/arch/cris/mm/fault.c deleted file mode 100644 index 29cc58038b98..000000000000 --- a/arch/cris/mm/fault.c +++ /dev/null @@ -1,390 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -/* - * arch/cris/mm/fault.c - * - * Copyright (C) 2000-2010 Axis Communications AB - */ - -#include <linux/mm.h> -#include <linux/interrupt.h> -#include <linux/extable.h> -#include <linux/wait.h> -#include <linux/sched/signal.h> -#include <linux/uaccess.h> -#include <arch/system.h> - -extern int find_fixup_code(struct pt_regs *); -extern void die_if_kernel(const char *, struct pt_regs *, long); -extern void show_registers(struct pt_regs *regs); - -/* debug of low-level TLB reload */ -#undef DEBUG - -#ifdef DEBUG -#define D(x) x -#else -#define D(x) -#endif - -/* debug of higher-level faults */ -#define DPG(x) - -/* current active page directory */ - -DEFINE_PER_CPU(pgd_t *, current_pgd); -unsigned long cris_signal_return_page; - -/* - * This routine handles page faults. It determines the address, - * and the problem, and then passes it off to one of the appropriate - * routines. - * - * Notice that the address we're given is aligned to the page the fault - * occurred in, since we only get the PFN in R_MMU_CAUSE not the complete - * address. - * - * error_code: - * bit 0 == 0 means no page found, 1 means protection fault - * bit 1 == 0 means read, 1 means write - * - * If this routine detects a bad access, it returns 1, otherwise it - * returns 0. - */ - -asmlinkage void -do_page_fault(unsigned long address, struct pt_regs *regs, - int protection, int writeaccess) -{ - struct task_struct *tsk; - struct mm_struct *mm; - struct vm_area_struct * vma; - siginfo_t info; - int fault; - unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; - - D(printk(KERN_DEBUG - "Page fault for %lX on %X at %lX, prot %d write %d\n", - address, smp_processor_id(), instruction_pointer(regs), - protection, writeaccess)); - - tsk = current; - - /* - * We fault-in kernel-space virtual memory on-demand. The - * 'reference' page table is init_mm.pgd. - * - * NOTE! We MUST NOT take any locks for this case. We may - * be in an interrupt or a critical region, and should - * only copy the information from the master page table, - * nothing more. - * - * NOTE2: This is done so that, when updating the vmalloc - * mappings we don't have to walk all processes pgdirs and - * add the high mappings all at once. Instead we do it as they - * are used. However vmalloc'ed page entries have the PAGE_GLOBAL - * bit set so sometimes the TLB can use a lingering entry. - * - * This verifies that the fault happens in kernel space - * and that the fault was not a protection error (error_code & 1). - */ - - if (address >= VMALLOC_START && - !protection && - !user_mode(regs)) - goto vmalloc_fault; - - /* When stack execution is not allowed we store the signal - * trampolines in the reserved cris_signal_return_page. - * Handle this in the exact same way as vmalloc (we know - * that the mapping is there and is valid so no need to - * call handle_mm_fault). - */ - if (cris_signal_return_page && - address == cris_signal_return_page && - !protection && user_mode(regs)) - goto vmalloc_fault; - - /* we can and should enable interrupts at this point */ - local_irq_enable(); - - mm = tsk->mm; - info.si_code = SEGV_MAPERR; - - /* - * If we're in an interrupt, have pagefaults disabled or have no - * user context, we must not take the fault. - */ - - if (faulthandler_disabled() || !mm) - goto no_context; - - if (user_mode(regs)) - flags |= FAULT_FLAG_USER; -retry: - down_read(&mm->mmap_sem); - vma = find_vma(mm, address); - if (!vma) - goto bad_area; - if (vma->vm_start <= address) - goto good_area; - if (!(vma->vm_flags & VM_GROWSDOWN)) - goto bad_area; - if (user_mode(regs)) { - /* - * accessing the stack below usp is always a bug. - * we get page-aligned addresses so we can only check - * if we're within a page from usp, but that might be - * enough to catch brutal errors at least. - */ - if (address + PAGE_SIZE < rdusp()) - goto bad_area; - } - if (expand_stack(vma, address)) - goto bad_area; - - /* - * Ok, we have a good vm_area for this memory access, so - * we can handle it.. - */ - - good_area: - info.si_code = SEGV_ACCERR; - - /* first do some preliminary protection checks */ - - if (writeaccess == 2){ - if (!(vma->vm_flags & VM_EXEC)) - goto bad_area; - } else if (writeaccess == 1) { - if (!(vma->vm_flags & VM_WRITE)) - goto bad_area; - flags |= FAULT_FLAG_WRITE; - } else { - if (!(vma->vm_flags & (VM_READ | VM_EXEC))) - 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); - - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) - return; - - if (unlikely(fault & VM_FAULT_ERROR)) { - if (fault & VM_FAULT_OOM) - goto out_of_memory; - else if (fault & VM_FAULT_SIGSEGV) - goto bad_area; - else if (fault & VM_FAULT_SIGBUS) - goto do_sigbus; - BUG(); - } - - if (flags & FAULT_FLAG_ALLOW_RETRY) { - if (fault & VM_FAULT_MAJOR) - tsk->maj_flt++; - else - tsk->min_flt++; - if (fault & VM_FAULT_RETRY) { - flags &= ~FAULT_FLAG_ALLOW_RETRY; - flags |= FAULT_FLAG_TRIED; - - /* - * No need to up_read(&mm->mmap_sem) as we would - * have already released it in __lock_page_or_retry - * in mm/filemap.c. - */ - - goto retry; - } - } - - up_read(&mm->mmap_sem); - return; - - /* - * Something tried to access memory that isn't in our memory map.. - * Fix it, but check if it's kernel or user first.. - */ - - bad_area: - up_read(&mm->mmap_sem); - - bad_area_nosemaphore: - DPG(show_registers(regs)); - - /* User mode accesses just cause a SIGSEGV */ - - if (user_mode(regs)) { -#ifdef CONFIG_NO_SEGFAULT_TERMINATION - DECLARE_WAIT_QUEUE_HEAD(wq); -#endif - printk(KERN_NOTICE "%s (pid %d) segfaults for page " - "address %08lx at pc %08lx\n", - tsk->comm, tsk->pid, - address, instruction_pointer(regs)); - - /* With DPG on, we've already dumped registers above. */ - DPG(if (0)) - show_registers(regs); - -#ifdef CONFIG_NO_SEGFAULT_TERMINATION - wait_event_interruptible(wq, 0 == 1); -#else - info.si_signo = SIGSEGV; - info.si_errno = 0; - /* info.si_code has been set above */ - info.si_addr = (void *)address; - force_sig_info(SIGSEGV, &info, tsk); -#endif - return; - } - - no_context: - - /* Are we prepared to handle this kernel fault? - * - * (The kernel has valid exception-points in the source - * when it accesses user-memory. When it fails in one - * of those points, we find it in a table and do a jump - * to some fixup code that loads an appropriate error - * code) - */ - - if (find_fixup_code(regs)) - return; - - /* - * Oops. The kernel tried to access some bad page. We'll have to - * terminate things with extreme prejudice. - */ - - if (!oops_in_progress) { - oops_in_progress = 1; - if ((unsigned long) (address) < PAGE_SIZE) - printk(KERN_ALERT "Unable to handle kernel NULL " - "pointer dereference"); - else - printk(KERN_ALERT "Unable to handle kernel access" - " at virtual address %08lx\n", address); - - die_if_kernel("Oops", regs, (writeaccess << 1) | protection); - oops_in_progress = 0; - } - - do_exit(SIGKILL); - - /* - * We ran out of memory, or some other thing happened to us that made - * us unable to handle the page fault gracefully. - */ - - out_of_memory: - up_read(&mm->mmap_sem); - if (!user_mode(regs)) - goto no_context; - pagefault_out_of_memory(); - return; - - do_sigbus: - up_read(&mm->mmap_sem); - - /* - * Send a sigbus, regardless of whether we were in kernel - * or user mode. - */ - info.si_signo = SIGBUS; - info.si_errno = 0; - info.si_code = BUS_ADRERR; - info.si_addr = (void *)address; - force_sig_info(SIGBUS, &info, tsk); - - /* Kernel mode? Handle exceptions or die */ - if (!user_mode(regs)) - goto no_context; - return; - -vmalloc_fault: - { - /* - * Synchronize this task's top level page-table - * with the 'reference' page table. - * - * Use current_pgd instead of tsk->active_mm->pgd - * since the latter might be unavailable if this - * code is executed in a misfortunately run irq - * (like inside schedule() between switch_mm and - * switch_to...). - */ - - int offset = pgd_index(address); - pgd_t *pgd, *pgd_k; - pud_t *pud, *pud_k; - pmd_t *pmd, *pmd_k; - pte_t *pte_k; - - pgd = (pgd_t *)per_cpu(current_pgd, smp_processor_id()) + offset; - pgd_k = init_mm.pgd + offset; - - /* Since we're two-level, we don't need to do both - * set_pgd and set_pmd (they do the same thing). If - * we go three-level at some point, do the right thing - * with pgd_present and set_pgd here. - * - * Also, since the vmalloc area is global, we don't - * need to copy individual PTE's, it is enough to - * copy the pgd pointer into the pte page of the - * root task. If that is there, we'll find our pte if - * it exists. - */ - - pud = pud_offset(pgd, address); - pud_k = pud_offset(pgd_k, address); - if (!pud_present(*pud_k)) - goto no_context; - - pmd = pmd_offset(pud, address); - pmd_k = pmd_offset(pud_k, address); - - if (!pmd_present(*pmd_k)) - goto bad_area_nosemaphore; - - set_pmd(pmd, *pmd_k); - - /* Make sure the actual PTE exists as well to - * catch kernel vmalloc-area accesses to non-mapped - * addresses. If we don't do this, this will just - * silently loop forever. - */ - - pte_k = pte_offset_kernel(pmd_k, address); - if (!pte_present(*pte_k)) - goto no_context; - - return; - } -} - -/* Find fixup code. */ -int -find_fixup_code(struct pt_regs *regs) -{ - const struct exception_table_entry *fixup; - /* in case of delay slot fault (v32) */ - unsigned long ip = (instruction_pointer(regs) & ~0x1); - - fixup = search_exception_tables(ip); - if (fixup != 0) { - /* Adjust the instruction pointer in the stackframe. */ - instruction_pointer(regs) = fixup->fixup; - arch_fixup(regs); - return 1; - } - - return 0; -} |