Hexagon: Add page-fault support.
Signed-off-by: Richard Kuo <rkuo@codeaurora.org> Signed-off-by: Linas Vepstas <linas@codeaurora.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Richard Kuo
committed by
Linus Torvalds
Linus Torvalds
parent
a7e7984099
commit
499236d9db
187
arch/hexagon/mm/vm_fault.c
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187
arch/hexagon/mm/vm_fault.c
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/*
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* Memory fault handling for Hexagon
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*
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* Copyright (c) 2010-2011 Code Aurora Forum. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 and
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* only version 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*/
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/*
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* Page fault handling for the Hexagon Virtual Machine.
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* Can also be called by a native port emulating the HVM
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* execptions.
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*/
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#include <asm/pgtable.h>
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#include <asm/traps.h>
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#include <asm/uaccess.h>
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#include <linux/mm.h>
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#include <linux/signal.h>
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#include <linux/module.h>
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#include <linux/hardirq.h>
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/*
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* Decode of hardware exception sends us to one of several
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* entry points. At each, we generate canonical arguments
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* for handling by the abstract memory management code.
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*/
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#define FLT_IFETCH -1
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#define FLT_LOAD 0
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#define FLT_STORE 1
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/*
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* Canonical page fault handler
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*/
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void do_page_fault(unsigned long address, long cause, struct pt_regs *regs)
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{
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struct vm_area_struct *vma;
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struct mm_struct *mm = current->mm;
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siginfo_t info;
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int si_code = SEGV_MAPERR;
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int fault;
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const struct exception_table_entry *fixup;
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/*
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* If we're in an interrupt or have no user context,
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* then must not take the fault.
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*/
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if (unlikely(in_interrupt() || !mm))
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goto no_context;
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local_irq_enable();
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down_read(&mm->mmap_sem);
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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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/* Address space is OK. Now check access rights. */
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si_code = SEGV_ACCERR;
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switch (cause) {
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case FLT_IFETCH:
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if (!(vma->vm_flags & VM_EXEC))
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goto bad_area;
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break;
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case FLT_LOAD:
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if (!(vma->vm_flags & VM_READ))
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goto bad_area;
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break;
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case FLT_STORE:
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if (!(vma->vm_flags & VM_WRITE))
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goto bad_area;
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break;
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}
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fault = handle_mm_fault(mm, vma, address, (cause > 0));
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/* The most common case -- we are done. */
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if (likely(!(fault & VM_FAULT_ERROR))) {
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if (fault & VM_FAULT_MAJOR)
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current->maj_flt++;
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else
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current->min_flt++;
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up_read(&mm->mmap_sem);
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return;
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}
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up_read(&mm->mmap_sem);
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/* Handle copyin/out exception cases */
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if (!user_mode(regs))
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goto no_context;
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if (fault & VM_FAULT_OOM) {
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pagefault_out_of_memory();
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return;
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}
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/* User-mode address is in the memory map, but we are
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* unable to fix up the page fault.
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*/
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if (fault & VM_FAULT_SIGBUS) {
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info.si_signo = SIGBUS;
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info.si_code = BUS_ADRERR;
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}
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/* Address is not in the memory map */
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else {
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info.si_signo = SIGSEGV;
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info.si_code = SEGV_ACCERR;
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}
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info.si_errno = 0;
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info.si_addr = (void __user *)address;
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force_sig_info(info.si_code, &info, current);
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return;
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bad_area:
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up_read(&mm->mmap_sem);
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if (user_mode(regs)) {
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info.si_signo = SIGSEGV;
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info.si_errno = 0;
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info.si_code = si_code;
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info.si_addr = (void *)address;
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force_sig_info(SIGSEGV, &info, current);
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return;
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}
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/* Kernel-mode fault falls through */
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no_context:
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fixup = search_exception_tables(pt_elr(regs));
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if (fixup) {
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pt_set_elr(regs, fixup->fixup);
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return;
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}
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/* Things are looking very, very bad now */
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bust_spinlocks(1);
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printk(KERN_EMERG "Unable to handle kernel paging request at "
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"virtual address 0x%08lx, regs %p\n", address, regs);
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die("Bad Kernel VA", regs, SIGKILL);
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}
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void read_protection_fault(struct pt_regs *regs)
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{
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unsigned long badvadr = pt_badva(regs);
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do_page_fault(badvadr, FLT_LOAD, regs);
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}
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void write_protection_fault(struct pt_regs *regs)
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{
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unsigned long badvadr = pt_badva(regs);
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do_page_fault(badvadr, FLT_STORE, regs);
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}
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void execute_protection_fault(struct pt_regs *regs)
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{
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unsigned long badvadr = pt_badva(regs);
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do_page_fault(badvadr, FLT_IFETCH, regs);
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}
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