From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- arch/ia64/mm/fault.c | 308 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 308 insertions(+) create mode 100644 arch/ia64/mm/fault.c (limited to 'arch/ia64/mm/fault.c') diff --git a/arch/ia64/mm/fault.c b/arch/ia64/mm/fault.c new file mode 100644 index 000000000..ba5ba7acc --- /dev/null +++ b/arch/ia64/mm/fault.c @@ -0,0 +1,308 @@ +/* + * MMU fault handling support. + * + * Copyright (C) 1998-2002 Hewlett-Packard Co + * David Mosberger-Tang + */ +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include + +extern int die(char *, struct pt_regs *, long); + +#ifdef CONFIG_KPROBES +static inline int notify_page_fault(struct pt_regs *regs, int trap) +{ + int ret = 0; + + if (!user_mode(regs)) { + /* kprobe_running() needs smp_processor_id() */ + preempt_disable(); + if (kprobe_running() && kprobe_fault_handler(regs, trap)) + ret = 1; + preempt_enable(); + } + + return ret; +} +#else +static inline int notify_page_fault(struct pt_regs *regs, int trap) +{ + return 0; +} +#endif + +/* + * 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; + pud_t *pud; + pmd_t *pmd; + pte_t *ptep, pte; + + pgd = pgd_offset_k(address); + if (pgd_none(*pgd) || pgd_bad(*pgd)) + return 0; + + pud = pud_offset(pgd, 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; + struct siginfo si; + unsigned long mask; + int fault; + unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + + mask = ((((isr >> IA64_ISR_X_BIT) & 1UL) << VM_EXEC_BIT) + | (((isr >> IA64_ISR_W_BIT) & 1UL) << VM_WRITE_BIT)); + + /* mmap_sem is performance critical.... */ + prefetchw(&mm->mmap_sem); + + /* + * If we're in an interrupt or have no user context, we must not take the fault.. + */ + if (in_atomic() || !mm) + goto no_context; + +#ifdef CONFIG_VIRTUAL_MEM_MAP + /* + * If fault is in region 5 and we are in the kernel, we may already + * have the mmap_sem (pfn_valid macro is called during mmap). There + * is no vma for region 5 addr's anyway, so skip getting the semaphore + * and go directly to the exception handling code. + */ + + if ((REGION_NUMBER(address) == 5) && !user_mode(regs)) + goto bad_area_no_up; +#endif + + /* + * This is to handle the kprobes on user space access instructions + */ + if (notify_page_fault(regs, TRAP_BRKPT)) + return; + + if (user_mode(regs)) + flags |= FAULT_FLAG_USER; + if (mask & VM_WRITE) + flags |= FAULT_FLAG_WRITE; +retry: + down_read(&mm->mmap_sem); + + 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) ) + goto check_expansion; + + good_area: + 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 . 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(mm, vma, address, flags); + + if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + 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 (flags & FAULT_FLAG_ALLOW_RETRY) { + if (fault & VM_FAULT_MAJOR) + current->maj_flt++; + else + current->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; + + check_expansion: + if (!(prev_vma && (prev_vma->vm_flags & VM_GROWSUP) && (address == prev_vma->vm_end))) { + if (!vma) + goto bad_area; + if (!(vma->vm_flags & VM_GROWSDOWN)) + goto bad_area; + if (REGION_NUMBER(address) != REGION_NUMBER(vma->vm_start) + || REGION_OFFSET(address) >= RGN_MAP_LIMIT) + goto bad_area; + if (expand_stack(vma, address)) + goto bad_area; + } else { + vma = prev_vma; + if (REGION_NUMBER(address) != REGION_NUMBER(vma->vm_start) + || REGION_OFFSET(address) >= RGN_MAP_LIMIT) + goto bad_area; + /* + * Since the register backing store is accessed sequentially, + * we disallow growing it by more than a page at a time. + */ + if (address > vma->vm_end + PAGE_SIZE - sizeof(long)) + goto bad_area; + if (expand_upwards(vma, address)) + goto bad_area; + } + goto good_area; + + bad_area: + up_read(&mm->mmap_sem); +#ifdef CONFIG_VIRTUAL_MEM_MAP + bad_area_no_up: +#endif + 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)) { + si.si_signo = signal; + si.si_errno = 0; + si.si_code = code; + si.si_addr = (void __user *) address; + si.si_isr = isr; + si.si_flags = __ISR_VALID; + force_sig_info(signal, &si, current); + 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) + do_exit(SIGKILL); + return; + + out_of_memory: + up_read(&mm->mmap_sem); + if (!user_mode(regs)) + goto no_context; + pagefault_out_of_memory(); +} -- cgit v1.2.3-54-g00ecf