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1/*
2 * Memory fault handling for Hexagon
3 *
4 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
5 *
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.
9 *
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.
14 *
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
18 * 02110-1301, USA.
19 */
20
21/*
22 * Page fault handling for the Hexagon Virtual Machine.
23 * Can also be called by a native port emulating the HVM
24 * execptions.
25 */
26
27#include <asm/pgtable.h>
28#include <asm/traps.h>
29#include <linux/uaccess.h>
30#include <linux/mm.h>
31#include <linux/sched/signal.h>
32#include <linux/signal.h>
33#include <linux/extable.h>
34#include <linux/hardirq.h>
35
36/*
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.
40 */
41#define FLT_IFETCH -1
42#define FLT_LOAD 0
43#define FLT_STORE 1
44
45
46/*
47 * Canonical page fault handler
48 */
49void do_page_fault(unsigned long address, long cause, struct pt_regs *regs)
50{
51 struct vm_area_struct *vma;
52 struct mm_struct *mm = current->mm;
53 siginfo_t info;
54 int si_code = SEGV_MAPERR;
55 int fault;
56 const struct exception_table_entry *fixup;
57 unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
58
59 /*
60 * If we're in an interrupt or have no user context,
61 * then must not take the fault.
62 */
63 if (unlikely(in_interrupt() || !mm))
64 goto no_context;
65
66 local_irq_enable();
67
68 if (user_mode(regs))
69 flags |= FAULT_FLAG_USER;
70retry:
71 down_read(&mm->mmap_sem);
72 vma = find_vma(mm, address);
73 if (!vma)
74 goto bad_area;
75
76 if (vma->vm_start <= address)
77 goto good_area;
78
79 if (!(vma->vm_flags & VM_GROWSDOWN))
80 goto bad_area;
81
82 if (expand_stack(vma, address))
83 goto bad_area;
84
85good_area:
86 /* Address space is OK. Now check access rights. */
87 si_code = SEGV_ACCERR;
88
89 switch (cause) {
90 case FLT_IFETCH:
91 if (!(vma->vm_flags & VM_EXEC))
92 goto bad_area;
93 break;
94 case FLT_LOAD:
95 if (!(vma->vm_flags & VM_READ))
96 goto bad_area;
97 break;
98 case FLT_STORE:
99 if (!(vma->vm_flags & VM_WRITE))
100 goto bad_area;
101 flags |= FAULT_FLAG_WRITE;
102 break;
103 }
104
105 fault = handle_mm_fault(vma, address, flags);
106
107 if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
108 return;
109
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)
114 current->maj_flt++;
115 else
116 current->min_flt++;
117 if (fault & VM_FAULT_RETRY) {
118 flags &= ~FAULT_FLAG_ALLOW_RETRY;
119 flags |= FAULT_FLAG_TRIED;
120 goto retry;
121 }
122 }
123
124 up_read(&mm->mmap_sem);
125 return;
126 }
127
128 up_read(&mm->mmap_sem);
129
130 /* Handle copyin/out exception cases */
131 if (!user_mode(regs))
132 goto no_context;
133
134 if (fault & VM_FAULT_OOM) {
135 pagefault_out_of_memory();
136 return;
137 }
138
139 /* User-mode address is in the memory map, but we are
140 * unable to fix up the page fault.
141 */
142 if (fault & VM_FAULT_SIGBUS) {
143 info.si_signo = SIGBUS;
144 info.si_code = BUS_ADRERR;
145 }
146 /* Address is not in the memory map */
147 else {
148 info.si_signo = SIGSEGV;
149 info.si_code = SEGV_ACCERR;
150 }
151 info.si_errno = 0;
152 info.si_addr = (void __user *)address;
153 force_sig_info(info.si_signo, &info, current);
154 return;
155
156bad_area:
157 up_read(&mm->mmap_sem);
158
159 if (user_mode(regs)) {
160 info.si_signo = SIGSEGV;
161 info.si_errno = 0;
162 info.si_code = si_code;
163 info.si_addr = (void *)address;
164 force_sig_info(info.si_signo, &info, current);
165 return;
166 }
167 /* Kernel-mode fault falls through */
168
169no_context:
170 fixup = search_exception_tables(pt_elr(regs));
171 if (fixup) {
172 pt_set_elr(regs, fixup->fixup);
173 return;
174 }
175
176 /* Things are looking very, very bad now */
177 bust_spinlocks(1);
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);
181}
182
183
184void read_protection_fault(struct pt_regs *regs)
185{
186 unsigned long badvadr = pt_badva(regs);
187
188 do_page_fault(badvadr, FLT_LOAD, regs);
189}
190
191void write_protection_fault(struct pt_regs *regs)
192{
193 unsigned long badvadr = pt_badva(regs);
194
195 do_page_fault(badvadr, FLT_STORE, regs);
196}
197
198void execute_protection_fault(struct pt_regs *regs)
199{
200 unsigned long badvadr = pt_badva(regs);
201
202 do_page_fault(badvadr, FLT_IFETCH, regs);
203}
1/*
2 * Memory fault handling for Hexagon
3 *
4 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
5 *
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.
9 *
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.
14 *
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
18 * 02110-1301, USA.
19 */
20
21/*
22 * Page fault handling for the Hexagon Virtual Machine.
23 * Can also be called by a native port emulating the HVM
24 * execptions.
25 */
26
27#include <asm/pgtable.h>
28#include <asm/traps.h>
29#include <asm/uaccess.h>
30#include <linux/mm.h>
31#include <linux/signal.h>
32#include <linux/module.h>
33#include <linux/hardirq.h>
34
35/*
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.
39 */
40#define FLT_IFETCH -1
41#define FLT_LOAD 0
42#define FLT_STORE 1
43
44
45/*
46 * Canonical page fault handler
47 */
48void do_page_fault(unsigned long address, long cause, struct pt_regs *regs)
49{
50 struct vm_area_struct *vma;
51 struct mm_struct *mm = current->mm;
52 siginfo_t info;
53 int si_code = SEGV_MAPERR;
54 int fault;
55 const struct exception_table_entry *fixup;
56 unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
57
58 /*
59 * If we're in an interrupt or have no user context,
60 * then must not take the fault.
61 */
62 if (unlikely(in_interrupt() || !mm))
63 goto no_context;
64
65 local_irq_enable();
66
67 if (user_mode(regs))
68 flags |= FAULT_FLAG_USER;
69retry:
70 down_read(&mm->mmap_sem);
71 vma = find_vma(mm, address);
72 if (!vma)
73 goto bad_area;
74
75 if (vma->vm_start <= address)
76 goto good_area;
77
78 if (!(vma->vm_flags & VM_GROWSDOWN))
79 goto bad_area;
80
81 if (expand_stack(vma, address))
82 goto bad_area;
83
84good_area:
85 /* Address space is OK. Now check access rights. */
86 si_code = SEGV_ACCERR;
87
88 switch (cause) {
89 case FLT_IFETCH:
90 if (!(vma->vm_flags & VM_EXEC))
91 goto bad_area;
92 break;
93 case FLT_LOAD:
94 if (!(vma->vm_flags & VM_READ))
95 goto bad_area;
96 break;
97 case FLT_STORE:
98 if (!(vma->vm_flags & VM_WRITE))
99 goto bad_area;
100 flags |= FAULT_FLAG_WRITE;
101 break;
102 }
103
104 fault = handle_mm_fault(mm, vma, address, flags);
105
106 if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
107 return;
108
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)
113 current->maj_flt++;
114 else
115 current->min_flt++;
116 if (fault & VM_FAULT_RETRY) {
117 flags &= ~FAULT_FLAG_ALLOW_RETRY;
118 flags |= FAULT_FLAG_TRIED;
119 goto retry;
120 }
121 }
122
123 up_read(&mm->mmap_sem);
124 return;
125 }
126
127 up_read(&mm->mmap_sem);
128
129 /* Handle copyin/out exception cases */
130 if (!user_mode(regs))
131 goto no_context;
132
133 if (fault & VM_FAULT_OOM) {
134 pagefault_out_of_memory();
135 return;
136 }
137
138 /* User-mode address is in the memory map, but we are
139 * unable to fix up the page fault.
140 */
141 if (fault & VM_FAULT_SIGBUS) {
142 info.si_signo = SIGBUS;
143 info.si_code = BUS_ADRERR;
144 }
145 /* Address is not in the memory map */
146 else {
147 info.si_signo = SIGSEGV;
148 info.si_code = SEGV_ACCERR;
149 }
150 info.si_errno = 0;
151 info.si_addr = (void __user *)address;
152 force_sig_info(info.si_signo, &info, current);
153 return;
154
155bad_area:
156 up_read(&mm->mmap_sem);
157
158 if (user_mode(regs)) {
159 info.si_signo = SIGSEGV;
160 info.si_errno = 0;
161 info.si_code = si_code;
162 info.si_addr = (void *)address;
163 force_sig_info(info.si_signo, &info, current);
164 return;
165 }
166 /* Kernel-mode fault falls through */
167
168no_context:
169 fixup = search_exception_tables(pt_elr(regs));
170 if (fixup) {
171 pt_set_elr(regs, fixup->fixup);
172 return;
173 }
174
175 /* Things are looking very, very bad now */
176 bust_spinlocks(1);
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);
180}
181
182
183void read_protection_fault(struct pt_regs *regs)
184{
185 unsigned long badvadr = pt_badva(regs);
186
187 do_page_fault(badvadr, FLT_LOAD, regs);
188}
189
190void write_protection_fault(struct pt_regs *regs)
191{
192 unsigned long badvadr = pt_badva(regs);
193
194 do_page_fault(badvadr, FLT_STORE, regs);
195}
196
197void execute_protection_fault(struct pt_regs *regs)
198{
199 unsigned long badvadr = pt_badva(regs);
200
201 do_page_fault(badvadr, FLT_IFETCH, regs);
202}