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 |
57 (cause > 0 ? FAULT_FLAG_WRITE : 0);
60 * If we're in an interrupt or have no user context,
61 * then must not take the fault.
63 if (unlikely(in_interrupt() || !mm))
69 down_read(&mm->mmap_sem);
70 vma = find_vma(mm, address);
74 if (vma->vm_start <= address)
77 if (!(vma->vm_flags & VM_GROWSDOWN))
80 if (expand_stack(vma, address))
84 /* Address space is OK. Now check access rights. */
85 si_code = SEGV_ACCERR;
89 if (!(vma->vm_flags & VM_EXEC))
93 if (!(vma->vm_flags & VM_READ))
97 if (!(vma->vm_flags & VM_WRITE))
102 fault = handle_mm_fault(mm, vma, address, flags);
104 if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
107 /* The most common case -- we are done. */
108 if (likely(!(fault & VM_FAULT_ERROR))) {
109 if (flags & FAULT_FLAG_ALLOW_RETRY) {
110 if (fault & VM_FAULT_MAJOR)
114 if (fault & VM_FAULT_RETRY) {
115 flags &= ~FAULT_FLAG_ALLOW_RETRY;
116 flags |= FAULT_FLAG_TRIED;
121 up_read(&mm->mmap_sem);
125 up_read(&mm->mmap_sem);
127 /* Handle copyin/out exception cases */
128 if (!user_mode(regs))
131 if (fault & VM_FAULT_OOM) {
132 pagefault_out_of_memory();
136 /* User-mode address is in the memory map, but we are
137 * unable to fix up the page fault.
139 if (fault & VM_FAULT_SIGBUS) {
140 info.si_signo = SIGBUS;
141 info.si_code = BUS_ADRERR;
143 /* Address is not in the memory map */
145 info.si_signo = SIGSEGV;
146 info.si_code = SEGV_ACCERR;
149 info.si_addr = (void __user *)address;
150 force_sig_info(info.si_code, &info, current);
154 up_read(&mm->mmap_sem);
156 if (user_mode(regs)) {
157 info.si_signo = SIGSEGV;
159 info.si_code = si_code;
160 info.si_addr = (void *)address;
161 force_sig_info(SIGSEGV, &info, current);
164 /* Kernel-mode fault falls through */
167 fixup = search_exception_tables(pt_elr(regs));
169 pt_set_elr(regs, fixup->fixup);
173 /* Things are looking very, very bad now */
175 printk(KERN_EMERG "Unable to handle kernel paging request at "
176 "virtual address 0x%08lx, regs %p\n", address, regs);
177 die("Bad Kernel VA", regs, SIGKILL);
181 void read_protection_fault(struct pt_regs *regs)
183 unsigned long badvadr = pt_badva(regs);
185 do_page_fault(badvadr, FLT_LOAD, regs);
188 void write_protection_fault(struct pt_regs *regs)
190 unsigned long badvadr = pt_badva(regs);
192 do_page_fault(badvadr, FLT_STORE, regs);
195 void execute_protection_fault(struct pt_regs *regs)
197 unsigned long badvadr = pt_badva(regs);
199 do_page_fault(badvadr, FLT_IFETCH, regs);