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 <linux/uaccess.h>
31 #include <linux/sched/signal.h>
32 #include <linux/signal.h>
33 #include <linux/extable.h>
34 #include <linux/hardirq.h>
37 * Decode of hardware exception sends us to one of several
38 * entry points. At each, we generate canonical arguments
39 * for handling by the abstract memory management code.
47 * Canonical page fault handler
49 void do_page_fault(unsigned long address, long cause, struct pt_regs *regs)
51 struct vm_area_struct *vma;
52 struct mm_struct *mm = current->mm;
54 int si_code = SEGV_MAPERR;
56 const struct exception_table_entry *fixup;
57 unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
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 flags |= FAULT_FLAG_USER;
71 down_read(&mm->mmap_sem);
72 vma = find_vma(mm, address);
76 if (vma->vm_start <= address)
79 if (!(vma->vm_flags & VM_GROWSDOWN))
82 if (expand_stack(vma, address))
86 /* Address space is OK. Now check access rights. */
87 si_code = SEGV_ACCERR;
91 if (!(vma->vm_flags & VM_EXEC))
95 if (!(vma->vm_flags & VM_READ))
99 if (!(vma->vm_flags & VM_WRITE))
101 flags |= FAULT_FLAG_WRITE;
105 fault = handle_mm_fault(vma, address, flags);
107 if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
110 /* The most common case -- we are done. */
111 if (likely(!(fault & VM_FAULT_ERROR))) {
112 if (flags & FAULT_FLAG_ALLOW_RETRY) {
113 if (fault & VM_FAULT_MAJOR)
117 if (fault & VM_FAULT_RETRY) {
118 flags &= ~FAULT_FLAG_ALLOW_RETRY;
119 flags |= FAULT_FLAG_TRIED;
124 up_read(&mm->mmap_sem);
128 up_read(&mm->mmap_sem);
130 /* Handle copyin/out exception cases */
131 if (!user_mode(regs))
134 if (fault & VM_FAULT_OOM) {
135 pagefault_out_of_memory();
139 /* User-mode address is in the memory map, but we are
140 * unable to fix up the page fault.
142 if (fault & VM_FAULT_SIGBUS) {
143 info.si_signo = SIGBUS;
144 info.si_code = BUS_ADRERR;
146 /* Address is not in the memory map */
148 info.si_signo = SIGSEGV;
149 info.si_code = SEGV_ACCERR;
152 info.si_addr = (void __user *)address;
153 force_sig_info(info.si_signo, &info, current);
157 up_read(&mm->mmap_sem);
159 if (user_mode(regs)) {
160 info.si_signo = SIGSEGV;
162 info.si_code = si_code;
163 info.si_addr = (void *)address;
164 force_sig_info(info.si_signo, &info, current);
167 /* Kernel-mode fault falls through */
170 fixup = search_exception_tables(pt_elr(regs));
172 pt_set_elr(regs, fixup->fixup);
176 /* Things are looking very, very bad now */
178 printk(KERN_EMERG "Unable to handle kernel paging request at "
179 "virtual address 0x%08lx, regs %p\n", address, regs);
180 die("Bad Kernel VA", regs, SIGKILL);
184 void read_protection_fault(struct pt_regs *regs)
186 unsigned long badvadr = pt_badva(regs);
188 do_page_fault(badvadr, FLT_LOAD, regs);
191 void write_protection_fault(struct pt_regs *regs)
193 unsigned long badvadr = pt_badva(regs);
195 do_page_fault(badvadr, FLT_STORE, regs);
198 void execute_protection_fault(struct pt_regs *regs)
200 unsigned long badvadr = pt_badva(regs);
202 do_page_fault(badvadr, FLT_IFETCH, regs);