tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
arm64: MMU fault handling and page table management
This patch adds support for the handling of the MMU faults (exception
entry code introduced by a previous patch) and page table management.
The user translation table is pointed to by TTBR0 and the kernel one
(swapper_pg_dir) by TTBR1. There is no translation information shared or
address space overlapping between user and kernel page tables.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
+965
+67
arch/arm64/include/asm/page.h
+67
arch/arm64/include/asm/page.h
···
1
+
/*
2
+
* Based on arch/arm/include/asm/page.h
3
+
*
4
+
* Copyright (C) 1995-2003 Russell King
5
+
* Copyright (C) 2012 ARM Ltd.
6
+
*
7
+
* This program is free software; you can redistribute it and/or modify
8
+
* it under the terms of the GNU General Public License version 2 as
9
+
* published by the Free Software Foundation.
10
+
*
11
+
* This program is distributed in the hope that it will be useful,
12
+
* but WITHOUT ANY WARRANTY; without even the implied warranty of
13
+
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14
+
* GNU General Public License for more details.
15
+
*
16
+
* You should have received a copy of the GNU General Public License
17
+
* along with this program. If not, see <http://www.gnu.org/licenses/>.
18
+
*/
19
+
#ifndef __ASM_PAGE_H
20
+
#define __ASM_PAGE_H
21
+
22
+
/* PAGE_SHIFT determines the page size */
23
+
#ifdef CONFIG_ARM64_64K_PAGES
24
+
#define PAGE_SHIFT 16
25
+
#else
26
+
#define PAGE_SHIFT 12
27
+
#endif
28
+
#define PAGE_SIZE (_AC(1,UL) << PAGE_SHIFT)
29
+
#define PAGE_MASK (~(PAGE_SIZE-1))
30
+
31
+
/* We do define AT_SYSINFO_EHDR but don't use the gate mechanism */
32
+
#define __HAVE_ARCH_GATE_AREA 1
33
+
34
+
#ifndef __ASSEMBLY__
35
+
36
+
#ifdef CONFIG_ARM64_64K_PAGES
37
+
#include <asm/pgtable-2level-types.h>
38
+
#else
39
+
#include <asm/pgtable-3level-types.h>
40
+
#endif
41
+
42
+
extern void __cpu_clear_user_page(void *p, unsigned long user);
43
+
extern void __cpu_copy_user_page(void *to, const void *from,
44
+
unsigned long user);
45
+
extern void copy_page(void *to, const void *from);
46
+
extern void clear_page(void *to);
47
+
48
+
#define clear_user_page(addr,vaddr,pg) __cpu_clear_user_page(addr, vaddr)
49
+
#define copy_user_page(to,from,vaddr,pg) __cpu_copy_user_page(to, from, vaddr)
50
+
51
+
typedef struct page *pgtable_t;
52
+
53
+
#ifdef CONFIG_HAVE_ARCH_PFN_VALID
54
+
extern int pfn_valid(unsigned long);
55
+
#endif
56
+
57
+
#include <asm/memory.h>
58
+
59
+
#endif /* !__ASSEMBLY__ */
60
+
61
+
#define VM_DATA_DEFAULT_FLAGS \
62
+
(((current->personality & READ_IMPLIES_EXEC) ? VM_EXEC : 0) | \
63
+
VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
64
+
65
+
#include <asm-generic/getorder.h>
66
+
67
+
#endif
+113
arch/arm64/include/asm/pgalloc.h
+113
arch/arm64/include/asm/pgalloc.h
···
1
+
/*
2
+
* Based on arch/arm/include/asm/pgalloc.h
3
+
*
4
+
* Copyright (C) 2000-2001 Russell King
5
+
* Copyright (C) 2012 ARM Ltd.
6
+
*
7
+
* This program is free software; you can redistribute it and/or modify
8
+
* it under the terms of the GNU General Public License version 2 as
9
+
* published by the Free Software Foundation.
10
+
*
11
+
* This program is distributed in the hope that it will be useful,
12
+
* but WITHOUT ANY WARRANTY; without even the implied warranty of
13
+
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14
+
* GNU General Public License for more details.
15
+
*
16
+
* You should have received a copy of the GNU General Public License
17
+
* along with this program. If not, see <http://www.gnu.org/licenses/>.
18
+
*/
19
+
#ifndef __ASM_PGALLOC_H
20
+
#define __ASM_PGALLOC_H
21
+
22
+
#include <asm/pgtable-hwdef.h>
23
+
#include <asm/processor.h>
24
+
#include <asm/cacheflush.h>
25
+
#include <asm/tlbflush.h>
26
+
27
+
#define check_pgt_cache() do { } while (0)
28
+
29
+
#ifndef CONFIG_ARM64_64K_PAGES
30
+
31
+
static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
32
+
{
33
+
return (pmd_t *)get_zeroed_page(GFP_KERNEL | __GFP_REPEAT);
34
+
}
35
+
36
+
static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
37
+
{
38
+
BUG_ON((unsigned long)pmd & (PAGE_SIZE-1));
39
+
free_page((unsigned long)pmd);
40
+
}
41
+
42
+
static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)
43
+
{
44
+
set_pud(pud, __pud(__pa(pmd) | PMD_TYPE_TABLE));
45
+
}
46
+
47
+
#endif /* CONFIG_ARM64_64K_PAGES */
48
+
49
+
extern pgd_t *pgd_alloc(struct mm_struct *mm);
50
+
extern void pgd_free(struct mm_struct *mm, pgd_t *pgd);
51
+
52
+
#define PGALLOC_GFP (GFP_KERNEL | __GFP_NOTRACK | __GFP_REPEAT | __GFP_ZERO)
53
+
54
+
static inline pte_t *
55
+
pte_alloc_one_kernel(struct mm_struct *mm, unsigned long addr)
56
+
{
57
+
return (pte_t *)__get_free_page(PGALLOC_GFP);
58
+
}
59
+
60
+
static inline pgtable_t
61
+
pte_alloc_one(struct mm_struct *mm, unsigned long addr)
62
+
{
63
+
struct page *pte;
64
+
65
+
pte = alloc_pages(PGALLOC_GFP, 0);
66
+
if (pte)
67
+
pgtable_page_ctor(pte);
68
+
69
+
return pte;
70
+
}
71
+
72
+
/*
73
+
* Free a PTE table.
74
+
*/
75
+
static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
76
+
{
77
+
if (pte)
78
+
free_page((unsigned long)pte);
79
+
}
80
+
81
+
static inline void pte_free(struct mm_struct *mm, pgtable_t pte)
82
+
{
83
+
pgtable_page_dtor(pte);
84
+
__free_page(pte);
85
+
}
86
+
87
+
static inline void __pmd_populate(pmd_t *pmdp, phys_addr_t pte,
88
+
pmdval_t prot)
89
+
{
90
+
set_pmd(pmdp, __pmd(pte | prot));
91
+
}
92
+
93
+
/*
94
+
* Populate the pmdp entry with a pointer to the pte. This pmd is part
95
+
* of the mm address space.
96
+
*/
97
+
static inline void
98
+
pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmdp, pte_t *ptep)
99
+
{
100
+
/*
101
+
* The pmd must be loaded with the physical address of the PTE table
102
+
*/
103
+
__pmd_populate(pmdp, __pa(ptep), PMD_TYPE_TABLE);
104
+
}
105
+
106
+
static inline void
107
+
pmd_populate(struct mm_struct *mm, pmd_t *pmdp, pgtable_t ptep)
108
+
{
109
+
__pmd_populate(pmdp, page_to_phys(ptep), PMD_TYPE_TABLE);
110
+
}
111
+
#define pmd_pgtable(pmd) pmd_page(pmd)
112
+
113
+
#endif
+34
arch/arm64/mm/copypage.c
+34
arch/arm64/mm/copypage.c
···
1
+
/*
2
+
* Based on arch/arm/mm/copypage.c
3
+
*
4
+
* Copyright (C) 2002 Deep Blue Solutions Ltd, All Rights Reserved.
5
+
* Copyright (C) 2012 ARM Ltd.
6
+
*
7
+
* This program is free software; you can redistribute it and/or modify
8
+
* it under the terms of the GNU General Public License version 2 as
9
+
* published by the Free Software Foundation.
10
+
*
11
+
* This program is distributed in the hope that it will be useful,
12
+
* but WITHOUT ANY WARRANTY; without even the implied warranty of
13
+
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14
+
* GNU General Public License for more details.
15
+
*
16
+
* You should have received a copy of the GNU General Public License
17
+
* along with this program. If not, see <http://www.gnu.org/licenses/>.
18
+
*/
19
+
20
+
#include <linux/mm.h>
21
+
22
+
#include <asm/page.h>
23
+
#include <asm/cacheflush.h>
24
+
25
+
void __cpu_copy_user_page(void *kto, const void *kfrom, unsigned long vaddr)
26
+
{
27
+
copy_page(kto, kfrom);
28
+
__flush_dcache_area(kto, PAGE_SIZE);
29
+
}
30
+
31
+
void __cpu_clear_user_page(void *kaddr, unsigned long vaddr)
32
+
{
33
+
clear_page(kaddr);
34
+
}
+17
arch/arm64/mm/extable.c
+17
arch/arm64/mm/extable.c
···
1
+
/*
2
+
* Based on arch/arm/mm/extable.c
3
+
*/
4
+
5
+
#include <linux/module.h>
6
+
#include <linux/uaccess.h>
7
+
8
+
int fixup_exception(struct pt_regs *regs)
9
+
{
10
+
const struct exception_table_entry *fixup;
11
+
12
+
fixup = search_exception_tables(instruction_pointer(regs));
13
+
if (fixup)
14
+
regs->pc = fixup->fixup;
15
+
16
+
return fixup != NULL;
17
+
}
+534
arch/arm64/mm/fault.c
+534
arch/arm64/mm/fault.c
···
1
+
/*
2
+
* Based on arch/arm/mm/fault.c
3
+
*
4
+
* Copyright (C) 1995 Linus Torvalds
5
+
* Copyright (C) 1995-2004 Russell King
6
+
* Copyright (C) 2012 ARM Ltd.
7
+
*
8
+
* This program is free software; you can redistribute it and/or modify
9
+
* it under the terms of the GNU General Public License version 2 as
10
+
* published by the Free Software Foundation.
11
+
*
12
+
* This program is distributed in the hope that it will be useful,
13
+
* but WITHOUT ANY WARRANTY; without even the implied warranty of
14
+
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15
+
* GNU General Public License for more details.
16
+
*
17
+
* You should have received a copy of the GNU General Public License
18
+
* along with this program. If not, see <http://www.gnu.org/licenses/>.
19
+
*/
20
+
21
+
#include <linux/module.h>
22
+
#include <linux/signal.h>
23
+
#include <linux/mm.h>
24
+
#include <linux/hardirq.h>
25
+
#include <linux/init.h>
26
+
#include <linux/kprobes.h>
27
+
#include <linux/uaccess.h>
28
+
#include <linux/page-flags.h>
29
+
#include <linux/sched.h>
30
+
#include <linux/highmem.h>
31
+
#include <linux/perf_event.h>
32
+
33
+
#include <asm/exception.h>
34
+
#include <asm/debug-monitors.h>
35
+
#include <asm/system_misc.h>
36
+
#include <asm/pgtable.h>
37
+
#include <asm/tlbflush.h>
38
+
39
+
/*
40
+
* Dump out the page tables associated with 'addr' in mm 'mm'.
41
+
*/
42
+
void show_pte(struct mm_struct *mm, unsigned long addr)
43
+
{
44
+
pgd_t *pgd;
45
+
46
+
if (!mm)
47
+
mm = &init_mm;
48
+
49
+
pr_alert("pgd = %p\n", mm->pgd);
50
+
pgd = pgd_offset(mm, addr);
51
+
pr_alert("[%08lx] *pgd=%016llx", addr, pgd_val(*pgd));
52
+
53
+
do {
54
+
pud_t *pud;
55
+
pmd_t *pmd;
56
+
pte_t *pte;
57
+
58
+
if (pgd_none_or_clear_bad(pgd))
59
+
break;
60
+
61
+
pud = pud_offset(pgd, addr);
62
+
if (pud_none_or_clear_bad(pud))
63
+
break;
64
+
65
+
pmd = pmd_offset(pud, addr);
66
+
printk(", *pmd=%016llx", pmd_val(*pmd));
67
+
if (pmd_none_or_clear_bad(pmd))
68
+
break;
69
+
70
+
pte = pte_offset_map(pmd, addr);
71
+
printk(", *pte=%016llx", pte_val(*pte));
72
+
pte_unmap(pte);
73
+
} while(0);
74
+
75
+
printk("\n");
76
+
}
77
+
78
+
/*
79
+
* The kernel tried to access some page that wasn't present.
80
+
*/
81
+
static void __do_kernel_fault(struct mm_struct *mm, unsigned long addr,
82
+
unsigned int esr, struct pt_regs *regs)
83
+
{
84
+
/*
85
+
* Are we prepared to handle this kernel fault?
86
+
*/
87
+
if (fixup_exception(regs))
88
+
return;
89
+
90
+
/*
91
+
* No handler, we'll have to terminate things with extreme prejudice.
92
+
*/
93
+
bust_spinlocks(1);
94
+
pr_alert("Unable to handle kernel %s at virtual address %08lx\n",
95
+
(addr < PAGE_SIZE) ? "NULL pointer dereference" :
96
+
"paging request", addr);
97
+
98
+
show_pte(mm, addr);
99
+
die("Oops", regs, esr);
100
+
bust_spinlocks(0);
101
+
do_exit(SIGKILL);
102
+
}
103
+
104
+
/*
105
+
* Something tried to access memory that isn't in our memory map. User mode
106
+
* accesses just cause a SIGSEGV
107
+
*/
108
+
static void __do_user_fault(struct task_struct *tsk, unsigned long addr,
109
+
unsigned int esr, unsigned int sig, int code,
110
+
struct pt_regs *regs)
111
+
{
112
+
struct siginfo si;
113
+
114
+
if (show_unhandled_signals) {
115
+
pr_info("%s[%d]: unhandled page fault (%d) at 0x%08lx, code 0x%03x\n",
116
+
tsk->comm, task_pid_nr(tsk), sig, addr, esr);
117
+
show_pte(tsk->mm, addr);
118
+
show_regs(regs);
119
+
}
120
+
121
+
tsk->thread.fault_address = addr;
122
+
si.si_signo = sig;
123
+
si.si_errno = 0;
124
+
si.si_code = code;
125
+
si.si_addr = (void __user *)addr;
126
+
force_sig_info(sig, &si, tsk);
127
+
}
128
+
129
+
void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *regs)
130
+
{
131
+
struct task_struct *tsk = current;
132
+
struct mm_struct *mm = tsk->active_mm;
133
+
134
+
/*
135
+
* If we are in kernel mode at this point, we have no context to
136
+
* handle this fault with.
137
+
*/
138
+
if (user_mode(regs))
139
+
__do_user_fault(tsk, addr, esr, SIGSEGV, SEGV_MAPERR, regs);
140
+
else
141
+
__do_kernel_fault(mm, addr, esr, regs);
142
+
}
143
+
144
+
#define VM_FAULT_BADMAP 0x010000
145
+
#define VM_FAULT_BADACCESS 0x020000
146
+
147
+
#define ESR_WRITE (1 << 6)
148
+
#define ESR_LNX_EXEC (1 << 24)
149
+
150
+
/*
151
+
* Check that the permissions on the VMA allow for the fault which occurred.
152
+
* If we encountered a write fault, we must have write permission, otherwise
153
+
* we allow any permission.
154
+
*/
155
+
static inline bool access_error(unsigned int esr, struct vm_area_struct *vma)
156
+
{
157
+
unsigned int mask = VM_READ | VM_WRITE | VM_EXEC;
158
+
159
+
if (esr & ESR_WRITE)
160
+
mask = VM_WRITE;
161
+
if (esr & ESR_LNX_EXEC)
162
+
mask = VM_EXEC;
163
+
164
+
return vma->vm_flags & mask ? false : true;
165
+
}
166
+
167
+
static int __do_page_fault(struct mm_struct *mm, unsigned long addr,
168
+
unsigned int esr, unsigned int flags,
169
+
struct task_struct *tsk)
170
+
{
171
+
struct vm_area_struct *vma;
172
+
int fault;
173
+
174
+
vma = find_vma(mm, addr);
175
+
fault = VM_FAULT_BADMAP;
176
+
if (unlikely(!vma))
177
+
goto out;
178
+
if (unlikely(vma->vm_start > addr))
179
+
goto check_stack;
180
+
181
+
/*
182
+
* Ok, we have a good vm_area for this memory access, so we can handle
183
+
* it.
184
+
*/
185
+
good_area:
186
+
if (access_error(esr, vma)) {
187
+
fault = VM_FAULT_BADACCESS;
188
+
goto out;
189
+
}
190
+
191
+
return handle_mm_fault(mm, vma, addr & PAGE_MASK, flags);
192
+
193
+
check_stack:
194
+
if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr))
195
+
goto good_area;
196
+
out:
197
+
return fault;
198
+
}
199
+
200
+
static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
201
+
struct pt_regs *regs)
202
+
{
203
+
struct task_struct *tsk;
204
+
struct mm_struct *mm;
205
+
int fault, sig, code;
206
+
int write = esr & ESR_WRITE;
207
+
unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
208
+
(write ? FAULT_FLAG_WRITE : 0);
209
+
210
+
tsk = current;
211
+
mm = tsk->mm;
212
+
213
+
/* Enable interrupts if they were enabled in the parent context. */
214
+
if (interrupts_enabled(regs))
215
+
local_irq_enable();
216
+
217
+
/*
218
+
* If we're in an interrupt or have no user context, we must not take
219
+
* the fault.
220
+
*/
221
+
if (in_atomic() || !mm)
222
+
goto no_context;
223
+
224
+
/*
225
+
* As per x86, we may deadlock here. However, since the kernel only
226
+
* validly references user space from well defined areas of the code,
227
+
* we can bug out early if this is from code which shouldn't.
228
+
*/
229
+
if (!down_read_trylock(&mm->mmap_sem)) {
230
+
if (!user_mode(regs) && !search_exception_tables(regs->pc))
231
+
goto no_context;
232
+
retry:
233
+
down_read(&mm->mmap_sem);
234
+
} else {
235
+
/*
236
+
* The above down_read_trylock() might have succeeded in which
237
+
* case, we'll have missed the might_sleep() from down_read().
238
+
*/
239
+
might_sleep();
240
+
#ifdef CONFIG_DEBUG_VM
241
+
if (!user_mode(regs) && !search_exception_tables(regs->pc))
242
+
goto no_context;
243
+
#endif
244
+
}
245
+
246
+
fault = __do_page_fault(mm, addr, esr, flags, tsk);
247
+
248
+
/*
249
+
* If we need to retry but a fatal signal is pending, handle the
250
+
* signal first. We do not need to release the mmap_sem because it
251
+
* would already be released in __lock_page_or_retry in mm/filemap.c.
252
+
*/
253
+
if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
254
+
return 0;
255
+
256
+
/*
257
+
* Major/minor page fault accounting is only done on the initial
258
+
* attempt. If we go through a retry, it is extremely likely that the
259
+
* page will be found in page cache at that point.
260
+
*/
261
+
262
+
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);
263
+
if (flags & FAULT_FLAG_ALLOW_RETRY) {
264
+
if (fault & VM_FAULT_MAJOR) {
265
+
tsk->maj_flt++;
266
+
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs,
267
+
addr);
268
+
} else {
269
+
tsk->min_flt++;
270
+
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs,
271
+
addr);
272
+
}
273
+
if (fault & VM_FAULT_RETRY) {
274
+
/*
275
+
* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk of
276
+
* starvation.
277
+
*/
278
+
flags &= ~FAULT_FLAG_ALLOW_RETRY;
279
+
goto retry;
280
+
}
281
+
}
282
+
283
+
up_read(&mm->mmap_sem);
284
+
285
+
/*
286
+
* Handle the "normal" case first - VM_FAULT_MAJOR / VM_FAULT_MINOR
287
+
*/
288
+
if (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP |
289
+
VM_FAULT_BADACCESS))))
290
+
return 0;
291
+
292
+
if (fault & VM_FAULT_OOM) {
293
+
/*
294
+
* We ran out of memory, call the OOM killer, and return to
295
+
* userspace (which will retry the fault, or kill us if we got
296
+
* oom-killed).
297
+
*/
298
+
pagefault_out_of_memory();
299
+
return 0;
300
+
}
301
+
302
+
/*
303
+
* If we are in kernel mode at this point, we have no context to
304
+
* handle this fault with.
305
+
*/
306
+
if (!user_mode(regs))
307
+
goto no_context;
308
+
309
+
if (fault & VM_FAULT_SIGBUS) {
310
+
/*
311
+
* We had some memory, but were unable to successfully fix up
312
+
* this page fault.
313
+
*/
314
+
sig = SIGBUS;
315
+
code = BUS_ADRERR;
316
+
} else {
317
+
/*
318
+
* Something tried to access memory that isn't in our memory
319
+
* map.
320
+
*/
321
+
sig = SIGSEGV;
322
+
code = fault == VM_FAULT_BADACCESS ?
323
+
SEGV_ACCERR : SEGV_MAPERR;
324
+
}
325
+
326
+
__do_user_fault(tsk, addr, esr, sig, code, regs);
327
+
return 0;
328
+
329
+
no_context:
330
+
__do_kernel_fault(mm, addr, esr, regs);
331
+
return 0;
332
+
}
333
+
334
+
/*
335
+
* First Level Translation Fault Handler
336
+
*
337
+
* We enter here because the first level page table doesn't contain a valid
338
+
* entry for the address.
339
+
*
340
+
* If the address is in kernel space (>= TASK_SIZE), then we are probably
341
+
* faulting in the vmalloc() area.
342
+
*
343
+
* If the init_task's first level page tables contains the relevant entry, we
344
+
* copy the it to this task. If not, we send the process a signal, fixup the
345
+
* exception, or oops the kernel.
346
+
*
347
+
* NOTE! We MUST NOT take any locks for this case. We may be in an interrupt
348
+
* or a critical region, and should only copy the information from the master
349
+
* page table, nothing more.
350
+
*/
351
+
static int __kprobes do_translation_fault(unsigned long addr,
352
+
unsigned int esr,
353
+
struct pt_regs *regs)
354
+
{
355
+
if (addr < TASK_SIZE)
356
+
return do_page_fault(addr, esr, regs);
357
+
358
+
do_bad_area(addr, esr, regs);
359
+
return 0;
360
+
}
361
+
362
+
/*
363
+
* Some section permission faults need to be handled gracefully. They can
364
+
* happen due to a __{get,put}_user during an oops.
365
+
*/
366
+
static int do_sect_fault(unsigned long addr, unsigned int esr,
367
+
struct pt_regs *regs)
368
+
{
369
+
do_bad_area(addr, esr, regs);
370
+
return 0;
371
+
}
372
+
373
+
/*
374
+
* This abort handler always returns "fault".
375
+
*/
376
+
static int do_bad(unsigned long addr, unsigned int esr, struct pt_regs *regs)
377
+
{
378
+
return 1;
379
+
}
380
+
381
+
static struct fault_info {
382
+
int (*fn)(unsigned long addr, unsigned int esr, struct pt_regs *regs);
383
+
int sig;
384
+
int code;
385
+
const char *name;
386
+
} fault_info[] = {
387
+
{ do_bad, SIGBUS, 0, "ttbr address size fault" },
388
+
{ do_bad, SIGBUS, 0, "level 1 address size fault" },
389
+
{ do_bad, SIGBUS, 0, "level 2 address size fault" },
390
+
{ do_bad, SIGBUS, 0, "level 3 address size fault" },
391
+
{ do_translation_fault, SIGSEGV, SEGV_MAPERR, "input address range fault" },
392
+
{ do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 1 translation fault" },
393
+
{ do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 2 translation fault" },
394
+
{ do_page_fault, SIGSEGV, SEGV_MAPERR, "level 3 translation fault" },
395
+
{ do_bad, SIGBUS, 0, "reserved access flag fault" },
396
+
{ do_bad, SIGSEGV, SEGV_ACCERR, "level 1 access flag fault" },
397
+
{ do_bad, SIGSEGV, SEGV_ACCERR, "level 2 access flag fault" },
398
+
{ do_page_fault, SIGSEGV, SEGV_ACCERR, "level 3 access flag fault" },
399
+
{ do_bad, SIGBUS, 0, "reserved permission fault" },
400
+
{ do_bad, SIGSEGV, SEGV_ACCERR, "level 1 permission fault" },
401
+
{ do_sect_fault, SIGSEGV, SEGV_ACCERR, "level 2 permission fault" },
402
+
{ do_page_fault, SIGSEGV, SEGV_ACCERR, "level 3 permission fault" },
403
+
{ do_bad, SIGBUS, 0, "synchronous external abort" },
404
+
{ do_bad, SIGBUS, 0, "asynchronous external abort" },
405
+
{ do_bad, SIGBUS, 0, "unknown 18" },
406
+
{ do_bad, SIGBUS, 0, "unknown 19" },
407
+
{ do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" },
408
+
{ do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" },
409
+
{ do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" },
410
+
{ do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" },
411
+
{ do_bad, SIGBUS, 0, "synchronous parity error" },
412
+
{ do_bad, SIGBUS, 0, "asynchronous parity error" },
413
+
{ do_bad, SIGBUS, 0, "unknown 26" },
414
+
{ do_bad, SIGBUS, 0, "unknown 27" },
415
+
{ do_bad, SIGBUS, 0, "synchronous parity error (translation table walk" },
416
+
{ do_bad, SIGBUS, 0, "synchronous parity error (translation table walk" },
417
+
{ do_bad, SIGBUS, 0, "synchronous parity error (translation table walk" },
418
+
{ do_bad, SIGBUS, 0, "synchronous parity error (translation table walk" },
419
+
{ do_bad, SIGBUS, 0, "unknown 32" },
420
+
{ do_bad, SIGBUS, BUS_ADRALN, "alignment fault" },
421
+
{ do_bad, SIGBUS, 0, "debug event" },
422
+
{ do_bad, SIGBUS, 0, "unknown 35" },
423
+
{ do_bad, SIGBUS, 0, "unknown 36" },
424
+
{ do_bad, SIGBUS, 0, "unknown 37" },
425
+
{ do_bad, SIGBUS, 0, "unknown 38" },
426
+
{ do_bad, SIGBUS, 0, "unknown 39" },
427
+
{ do_bad, SIGBUS, 0, "unknown 40" },
428
+
{ do_bad, SIGBUS, 0, "unknown 41" },
429
+
{ do_bad, SIGBUS, 0, "unknown 42" },
430
+
{ do_bad, SIGBUS, 0, "unknown 43" },
431
+
{ do_bad, SIGBUS, 0, "unknown 44" },
432
+
{ do_bad, SIGBUS, 0, "unknown 45" },
433
+
{ do_bad, SIGBUS, 0, "unknown 46" },
434
+
{ do_bad, SIGBUS, 0, "unknown 47" },
435
+
{ do_bad, SIGBUS, 0, "unknown 48" },
436
+
{ do_bad, SIGBUS, 0, "unknown 49" },
437
+
{ do_bad, SIGBUS, 0, "unknown 50" },
438
+
{ do_bad, SIGBUS, 0, "unknown 51" },
439
+
{ do_bad, SIGBUS, 0, "implementation fault (lockdown abort)" },
440
+
{ do_bad, SIGBUS, 0, "unknown 53" },
441
+
{ do_bad, SIGBUS, 0, "unknown 54" },
442
+
{ do_bad, SIGBUS, 0, "unknown 55" },
443
+
{ do_bad, SIGBUS, 0, "unknown 56" },
444
+
{ do_bad, SIGBUS, 0, "unknown 57" },
445
+
{ do_bad, SIGBUS, 0, "implementation fault (coprocessor abort)" },
446
+
{ do_bad, SIGBUS, 0, "unknown 59" },
447
+
{ do_bad, SIGBUS, 0, "unknown 60" },
448
+
{ do_bad, SIGBUS, 0, "unknown 61" },
449
+
{ do_bad, SIGBUS, 0, "unknown 62" },
450
+
{ do_bad, SIGBUS, 0, "unknown 63" },
451
+
};
452
+
453
+
/*
454
+
* Dispatch a data abort to the relevant handler.
455
+
*/
456
+
asmlinkage void __exception do_mem_abort(unsigned long addr, unsigned int esr,
457
+
struct pt_regs *regs)
458
+
{
459
+
const struct fault_info *inf = fault_info + (esr & 63);
460
+
struct siginfo info;
461
+
462
+
if (!inf->fn(addr, esr, regs))
463
+
return;
464
+
465
+
pr_alert("Unhandled fault: %s (0x%08x) at 0x%016lx\n",
466
+
inf->name, esr, addr);
467
+
468
+
info.si_signo = inf->sig;
469
+
info.si_errno = 0;
470
+
info.si_code = inf->code;
471
+
info.si_addr = (void __user *)addr;
472
+
arm64_notify_die("", regs, &info, esr);
473
+
}
474
+
475
+
/*
476
+
* Handle stack alignment exceptions.
477
+
*/
478
+
asmlinkage void __exception do_sp_pc_abort(unsigned long addr,
479
+
unsigned int esr,
480
+
struct pt_regs *regs)
481
+
{
482
+
struct siginfo info;
483
+
484
+
info.si_signo = SIGBUS;
485
+
info.si_errno = 0;
486
+
info.si_code = BUS_ADRALN;
487
+
info.si_addr = (void __user *)addr;
488
+
arm64_notify_die("", regs, &info, esr);
489
+
}
490
+
491
+
static struct fault_info debug_fault_info[] = {
492
+
{ do_bad, SIGTRAP, TRAP_HWBKPT, "hardware breakpoint" },
493
+
{ do_bad, SIGTRAP, TRAP_HWBKPT, "hardware single-step" },
494
+
{ do_bad, SIGTRAP, TRAP_HWBKPT, "hardware watchpoint" },
495
+
{ do_bad, SIGBUS, 0, "unknown 3" },
496
+
{ do_bad, SIGTRAP, TRAP_BRKPT, "aarch32 BKPT" },
497
+
{ do_bad, SIGTRAP, 0, "aarch32 vector catch" },
498
+
{ do_bad, SIGTRAP, TRAP_BRKPT, "aarch64 BRK" },
499
+
{ do_bad, SIGBUS, 0, "unknown 7" },
500
+
};
501
+
502
+
void __init hook_debug_fault_code(int nr,
503
+
int (*fn)(unsigned long, unsigned int, struct pt_regs *),
504
+
int sig, int code, const char *name)
505
+
{
506
+
BUG_ON(nr < 0 || nr >= ARRAY_SIZE(debug_fault_info));
507
+
508
+
debug_fault_info[nr].fn = fn;
509
+
debug_fault_info[nr].sig = sig;
510
+
debug_fault_info[nr].code = code;
511
+
debug_fault_info[nr].name = name;
512
+
}
513
+
514
+
asmlinkage int __exception do_debug_exception(unsigned long addr,
515
+
unsigned int esr,
516
+
struct pt_regs *regs)
517
+
{
518
+
const struct fault_info *inf = debug_fault_info + DBG_ESR_EVT(esr);
519
+
struct siginfo info;
520
+
521
+
if (!inf->fn(addr, esr, regs))
522
+
return 1;
523
+
524
+
pr_alert("Unhandled debug exception: %s (0x%08x) at 0x%016lx\n",
525
+
inf->name, esr, addr);
526
+
527
+
info.si_signo = inf->sig;
528
+
info.si_errno = 0;
529
+
info.si_code = inf->code;
530
+
info.si_addr = (void __user *)addr;
531
+
arm64_notify_die("", regs, &info, esr);
532
+
533
+
return 0;
534
+
}
+2
arch/arm64/mm/mm.h
+2
arch/arm64/mm/mm.h
+144
arch/arm64/mm/mmap.c
+144
arch/arm64/mm/mmap.c
···
1
+
/*
2
+
* Based on arch/arm/mm/mmap.c
3
+
*
4
+
* Copyright (C) 2012 ARM Ltd.
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 as
8
+
* 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, see <http://www.gnu.org/licenses/>.
17
+
*/
18
+
19
+
#include <linux/elf.h>
20
+
#include <linux/fs.h>
21
+
#include <linux/mm.h>
22
+
#include <linux/mman.h>
23
+
#include <linux/export.h>
24
+
#include <linux/shm.h>
25
+
#include <linux/sched.h>
26
+
#include <linux/io.h>
27
+
#include <linux/personality.h>
28
+
#include <linux/random.h>
29
+
30
+
#include <asm/cputype.h>
31
+
32
+
/*
33
+
* Leave enough space between the mmap area and the stack to honour ulimit in
34
+
* the face of randomisation.
35
+
*/
36
+
#define MIN_GAP (SZ_128M + ((STACK_RND_MASK << PAGE_SHIFT) + 1))
37
+
#define MAX_GAP (STACK_TOP/6*5)
38
+
39
+
static int mmap_is_legacy(void)
40
+
{
41
+
if (current->personality & ADDR_COMPAT_LAYOUT)
42
+
return 1;
43
+
44
+
if (rlimit(RLIMIT_STACK) == RLIM_INFINITY)
45
+
return 1;
46
+
47
+
return sysctl_legacy_va_layout;
48
+
}
49
+
50
+
/*
51
+
* Since get_random_int() returns the same value within a 1 jiffy window, we
52
+
* will almost always get the same randomisation for the stack and mmap
53
+
* region. This will mean the relative distance between stack and mmap will be
54
+
* the same.
55
+
*
56
+
* To avoid this we can shift the randomness by 1 bit.
57
+
*/
58
+
static unsigned long mmap_rnd(void)
59
+
{
60
+
unsigned long rnd = 0;
61
+
62
+
if (current->flags & PF_RANDOMIZE)
63
+
rnd = (long)get_random_int() & (STACK_RND_MASK >> 1);
64
+
65
+
return rnd << (PAGE_SHIFT + 1);
66
+
}
67
+
68
+
static unsigned long mmap_base(void)
69
+
{
70
+
unsigned long gap = rlimit(RLIMIT_STACK);
71
+
72
+
if (gap < MIN_GAP)
73
+
gap = MIN_GAP;
74
+
else if (gap > MAX_GAP)
75
+
gap = MAX_GAP;
76
+
77
+
return PAGE_ALIGN(STACK_TOP - gap - mmap_rnd());
78
+
}
79
+
80
+
/*
81
+
* This function, called very early during the creation of a new process VM
82
+
* image, sets up which VM layout function to use:
83
+
*/
84
+
void arch_pick_mmap_layout(struct mm_struct *mm)
85
+
{
86
+
/*
87
+
* Fall back to the standard layout if the personality bit is set, or
88
+
* if the expected stack growth is unlimited:
89
+
*/
90
+
if (mmap_is_legacy()) {
91
+
mm->mmap_base = TASK_UNMAPPED_BASE;
92
+
mm->get_unmapped_area = arch_get_unmapped_area;
93
+
mm->unmap_area = arch_unmap_area;
94
+
} else {
95
+
mm->mmap_base = mmap_base();
96
+
mm->get_unmapped_area = arch_get_unmapped_area_topdown;
97
+
mm->unmap_area = arch_unmap_area_topdown;
98
+
}
99
+
}
100
+
EXPORT_SYMBOL_GPL(arch_pick_mmap_layout);
101
+
102
+
103
+
/*
104
+
* You really shouldn't be using read() or write() on /dev/mem. This might go
105
+
* away in the future.
106
+
*/
107
+
int valid_phys_addr_range(unsigned long addr, size_t size)
108
+
{
109
+
if (addr < PHYS_OFFSET)
110
+
return 0;
111
+
if (addr + size > __pa(high_memory - 1) + 1)
112
+
return 0;
113
+
114
+
return 1;
115
+
}
116
+
117
+
/*
118
+
* Do not allow /dev/mem mappings beyond the supported physical range.
119
+
*/
120
+
int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
121
+
{
122
+
return !(((pfn << PAGE_SHIFT) + size) & ~PHYS_MASK);
123
+
}
124
+
125
+
#ifdef CONFIG_STRICT_DEVMEM
126
+
127
+
#include <linux/ioport.h>
128
+
129
+
/*
130
+
* devmem_is_allowed() checks to see if /dev/mem access to a certain address
131
+
* is valid. The argument is a physical page number. We mimic x86 here by
132
+
* disallowing access to system RAM as well as device-exclusive MMIO regions.
133
+
* This effectively disable read()/write() on /dev/mem.
134
+
*/
135
+
int devmem_is_allowed(unsigned long pfn)
136
+
{
137
+
if (iomem_is_exclusive(pfn << PAGE_SHIFT))
138
+
return 0;
139
+
if (!page_is_ram(pfn))
140
+
return 1;
141
+
return 0;
142
+
}
143
+
144
+
#endif
+54
arch/arm64/mm/pgd.c
+54
arch/arm64/mm/pgd.c
···
1
+
/*
2
+
* PGD allocation/freeing
3
+
*
4
+
* Copyright (C) 2012 ARM Ltd.
5
+
* Author: Catalin Marinas <catalin.marinas@arm.com>
6
+
*
7
+
* This program is free software; you can redistribute it and/or modify
8
+
* it under the terms of the GNU General Public License version 2 as
9
+
* published by the Free Software Foundation.
10
+
*
11
+
* This program is distributed in the hope that it will be useful,
12
+
* but WITHOUT ANY WARRANTY; without even the implied warranty of
13
+
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14
+
* GNU General Public License for more details.
15
+
*
16
+
* You should have received a copy of the GNU General Public License
17
+
* along with this program. If not, see <http://www.gnu.org/licenses/>.
18
+
*/
19
+
20
+
#include <linux/mm.h>
21
+
#include <linux/gfp.h>
22
+
#include <linux/highmem.h>
23
+
#include <linux/slab.h>
24
+
25
+
#include <asm/pgalloc.h>
26
+
#include <asm/page.h>
27
+
#include <asm/tlbflush.h>
28
+
29
+
#include "mm.h"
30
+
31
+
#define PGD_SIZE (PTRS_PER_PGD * sizeof(pgd_t))
32
+
33
+
pgd_t *pgd_alloc(struct mm_struct *mm)
34
+
{
35
+
pgd_t *new_pgd;
36
+
37
+
if (PGD_SIZE == PAGE_SIZE)
38
+
new_pgd = (pgd_t *)get_zeroed_page(GFP_KERNEL);
39
+
else
40
+
new_pgd = kzalloc(PGD_SIZE, GFP_KERNEL);
41
+
42
+
if (!new_pgd)
43
+
return NULL;
44
+
45
+
return new_pgd;
46
+
}
47
+
48
+
void pgd_free(struct mm_struct *mm, pgd_t *pgd)
49
+
{
50
+
if (PGD_SIZE == PAGE_SIZE)
51
+
free_page((unsigned long)pgd);
52
+
else
53
+
kfree(pgd);
54
+
}