2 * Memory fault handling for Hexagon
4 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 and
8 * only version 2 as published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
22 * Page fault handling for the Hexagon Virtual Machine.
23 * Can also be called by a native port emulating the HVM
27 #include <asm/pgtable.h>
28 #include <asm/traps.h>
29 #include <asm/uaccess.h>
31 #include <linux/signal.h>
32 #include <linux/module.h>
33 #include <linux/hardirq.h>
36 * Decode of hardware exception sends us to one of several
37 * entry points. At each, we generate canonical arguments
38 * for handling by the abstract memory management code.
46 * Canonical page fault handler
48 void do_page_fault(unsigned long address, long cause, struct pt_regs *regs)
50 struct vm_area_struct *vma;
51 struct mm_struct *mm = current->mm;
53 int si_code = SEGV_MAPERR;
55 const struct exception_table_entry *fixup;
56 unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
59 * If we're in an interrupt or have no user context,
60 * then must not take the fault.
62 if (unlikely(in_interrupt() || !mm))
68 flags |= FAULT_FLAG_USER;
70 down_read(&mm->mmap_sem);
71 vma = find_vma(mm, address);
75 if (vma->vm_start <= address)
78 if (!(vma->vm_flags & VM_GROWSDOWN))
81 if (expand_stack(vma, address))
85 /* Address space is OK. Now check access rights. */
86 si_code = SEGV_ACCERR;
90 if (!(vma->vm_flags & VM_EXEC))
94 if (!(vma->vm_flags & VM_READ))
98 if (!(vma->vm_flags & VM_WRITE))
100 flags |= FAULT_FLAG_WRITE;
104 fault = handle_mm_fault(mm, vma, address, flags);
106 if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
109 /* The most common case -- we are done. */
110 if (likely(!(fault & VM_FAULT_ERROR))) {
111 if (flags & FAULT_FLAG_ALLOW_RETRY) {
112 if (fault & VM_FAULT_MAJOR)
116 if (fault & VM_FAULT_RETRY) {
117 flags &= ~FAULT_FLAG_ALLOW_RETRY;
118 flags |= FAULT_FLAG_TRIED;
123 up_read(&mm->mmap_sem);
127 up_read(&mm->mmap_sem);
129 /* Handle copyin/out exception cases */
130 if (!user_mode(regs))
133 if (fault & VM_FAULT_OOM) {
134 pagefault_out_of_memory();
138 /* User-mode address is in the memory map, but we are
139 * unable to fix up the page fault.
141 if (fault & VM_FAULT_SIGBUS) {
142 info.si_signo = SIGBUS;
143 info.si_code = BUS_ADRERR;
145 /* Address is not in the memory map */
147 info.si_signo = SIGSEGV;
148 info.si_code = SEGV_ACCERR;
151 info.si_addr = (void __user *)address;
152 force_sig_info(info.si_signo, &info, current);
156 up_read(&mm->mmap_sem);
158 if (user_mode(regs)) {
159 info.si_signo = SIGSEGV;
161 info.si_code = si_code;
162 info.si_addr = (void *)address;
163 force_sig_info(info.si_signo, &info, current);
166 /* Kernel-mode fault falls through */
169 fixup = search_exception_tables(pt_elr(regs));
171 pt_set_elr(regs, fixup->fixup);
175 /* Things are looking very, very bad now */
177 printk(KERN_EMERG "Unable to handle kernel paging request at "
178 "virtual address 0x%08lx, regs %p\n", address, regs);
179 die("Bad Kernel VA", regs, SIGKILL);
183 void read_protection_fault(struct pt_regs *regs)
185 unsigned long badvadr = pt_badva(regs);
187 do_page_fault(badvadr, FLT_LOAD, regs);
190 void write_protection_fault(struct pt_regs *regs)
192 unsigned long badvadr = pt_badva(regs);
194 do_page_fault(badvadr, FLT_STORE, regs);
197 void execute_protection_fault(struct pt_regs *regs)
199 unsigned long badvadr = pt_badva(regs);
201 do_page_fault(badvadr, FLT_IFETCH, regs);