diff options
Diffstat (limited to 'kernel/arch/hexagon/mm/vm_fault.c')
| -rw-r--r-- | kernel/arch/hexagon/mm/vm_fault.c | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/kernel/arch/hexagon/mm/vm_fault.c b/kernel/arch/hexagon/mm/vm_fault.c new file mode 100644 index 000000000..8704c9320 --- /dev/null +++ b/kernel/arch/hexagon/mm/vm_fault.c @@ -0,0 +1,202 @@ +/* + * Memory fault handling for Hexagon + * + * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 and + * only version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + */ + +/* + * Page fault handling for the Hexagon Virtual Machine. + * Can also be called by a native port emulating the HVM + * execptions. + */ + +#include <asm/pgtable.h> +#include <asm/traps.h> +#include <asm/uaccess.h> +#include <linux/mm.h> +#include <linux/signal.h> +#include <linux/module.h> +#include <linux/hardirq.h> + +/* + * Decode of hardware exception sends us to one of several + * entry points. At each, we generate canonical arguments + * for handling by the abstract memory management code. + */ +#define FLT_IFETCH -1 +#define FLT_LOAD 0 +#define FLT_STORE 1 + + +/* + * Canonical page fault handler + */ +void do_page_fault(unsigned long address, long cause, struct pt_regs *regs) +{ + struct vm_area_struct *vma; + struct mm_struct *mm = current->mm; + siginfo_t info; + int si_code = SEGV_MAPERR; + int fault; + const struct exception_table_entry *fixup; + unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + + /* + * If we're in an interrupt or have no user context, + * then must not take the fault. + */ + if (unlikely(in_interrupt() || !mm)) + goto no_context; + + local_irq_enable(); + + 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 (expand_stack(vma, address)) + goto bad_area; + +good_area: + /* Address space is OK. Now check access rights. */ + si_code = SEGV_ACCERR; + + switch (cause) { + case FLT_IFETCH: + if (!(vma->vm_flags & VM_EXEC)) + goto bad_area; + break; + case FLT_LOAD: + if (!(vma->vm_flags & VM_READ)) + goto bad_area; + break; + case FLT_STORE: + if (!(vma->vm_flags & VM_WRITE)) + goto bad_area; + flags |= FAULT_FLAG_WRITE; + break; + } + + fault = handle_mm_fault(mm, vma, address, flags); + + if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + return; + + /* The most common case -- we are done. */ + if (likely(!(fault & VM_FAULT_ERROR))) { + 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; + goto retry; + } + } + + up_read(&mm->mmap_sem); + return; + } + + up_read(&mm->mmap_sem); + + /* Handle copyin/out exception cases */ + if (!user_mode(regs)) + goto no_context; + + if (fault & VM_FAULT_OOM) { + pagefault_out_of_memory(); + return; + } + + /* User-mode address is in the memory map, but we are + * unable to fix up the page fault. + */ + if (fault & VM_FAULT_SIGBUS) { + info.si_signo = SIGBUS; + info.si_code = BUS_ADRERR; + } + /* Address is not in the memory map */ + else { + info.si_signo = SIGSEGV; + info.si_code = SEGV_ACCERR; + } + info.si_errno = 0; + info.si_addr = (void __user *)address; + force_sig_info(info.si_signo, &info, current); + return; + +bad_area: + up_read(&mm->mmap_sem); + + if (user_mode(regs)) { + info.si_signo = SIGSEGV; + info.si_errno = 0; + info.si_code = si_code; + info.si_addr = (void *)address; + force_sig_info(info.si_signo, &info, current); + return; + } + /* Kernel-mode fault falls through */ + +no_context: + fixup = search_exception_tables(pt_elr(regs)); + if (fixup) { + pt_set_elr(regs, fixup->fixup); + return; + } + + /* Things are looking very, very bad now */ + bust_spinlocks(1); + printk(KERN_EMERG "Unable to handle kernel paging request at " + "virtual address 0x%08lx, regs %p\n", address, regs); + die("Bad Kernel VA", regs, SIGKILL); +} + + +void read_protection_fault(struct pt_regs *regs) +{ + unsigned long badvadr = pt_badva(regs); + + do_page_fault(badvadr, FLT_LOAD, regs); +} + +void write_protection_fault(struct pt_regs *regs) +{ + unsigned long badvadr = pt_badva(regs); + + do_page_fault(badvadr, FLT_STORE, regs); +} + +void execute_protection_fault(struct pt_regs *regs) +{ + unsigned long badvadr = pt_badva(regs); + + do_page_fault(badvadr, FLT_IFETCH, regs); +} |