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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 */
5
6#include <linux/err.h>
7#include <linux/highmem.h>
8#include <linux/mm.h>
9#include <linux/module.h>
10#include <linux/sched.h>
11#include <asm/current.h>
12#include <asm/page.h>
13#include <kern_util.h>
14#include <os.h>
15
16pte_t *virt_to_pte(struct mm_struct *mm, unsigned long addr)
17{
18 pgd_t *pgd;
19 p4d_t *p4d;
20 pud_t *pud;
21 pmd_t *pmd;
22
23 if (mm == NULL)
24 return NULL;
25
26 pgd = pgd_offset(mm, addr);
27 if (!pgd_present(*pgd))
28 return NULL;
29
30 p4d = p4d_offset(pgd, addr);
31 if (!p4d_present(*p4d))
32 return NULL;
33
34 pud = pud_offset(p4d, addr);
35 if (!pud_present(*pud))
36 return NULL;
37
38 pmd = pmd_offset(pud, addr);
39 if (!pmd_present(*pmd))
40 return NULL;
41
42 return pte_offset_kernel(pmd, addr);
43}
44
45static pte_t *maybe_map(unsigned long virt, int is_write)
46{
47 pte_t *pte = virt_to_pte(current->mm, virt);
48 int err, dummy_code;
49
50 if ((pte == NULL) || !pte_present(*pte) ||
51 (is_write && !pte_write(*pte))) {
52 err = handle_page_fault(virt, 0, is_write, 1, &dummy_code);
53 if (err)
54 return NULL;
55 pte = virt_to_pte(current->mm, virt);
56 }
57 if (!pte_present(*pte))
58 pte = NULL;
59
60 return pte;
61}
62
63static int do_op_one_page(unsigned long addr, int len, int is_write,
64 int (*op)(unsigned long addr, int len, void *arg), void *arg)
65{
66 struct page *page;
67 pte_t *pte;
68 int n;
69
70 pte = maybe_map(addr, is_write);
71 if (pte == NULL)
72 return -1;
73
74 page = pte_page(*pte);
75#ifdef CONFIG_64BIT
76 pagefault_disable();
77 addr = (unsigned long) page_address(page) +
78 (addr & ~PAGE_MASK);
79#else
80 addr = (unsigned long) kmap_atomic(page) +
81 (addr & ~PAGE_MASK);
82#endif
83 n = (*op)(addr, len, arg);
84
85#ifdef CONFIG_64BIT
86 pagefault_enable();
87#else
88 kunmap_atomic((void *)addr);
89#endif
90
91 return n;
92}
93
94static long buffer_op(unsigned long addr, int len, int is_write,
95 int (*op)(unsigned long, int, void *), void *arg)
96{
97 long size, remain, n;
98
99 size = min(PAGE_ALIGN(addr) - addr, (unsigned long) len);
100 remain = len;
101
102 n = do_op_one_page(addr, size, is_write, op, arg);
103 if (n != 0) {
104 remain = (n < 0 ? remain : 0);
105 goto out;
106 }
107
108 addr += size;
109 remain -= size;
110 if (remain == 0)
111 goto out;
112
113 while (addr < ((addr + remain) & PAGE_MASK)) {
114 n = do_op_one_page(addr, PAGE_SIZE, is_write, op, arg);
115 if (n != 0) {
116 remain = (n < 0 ? remain : 0);
117 goto out;
118 }
119
120 addr += PAGE_SIZE;
121 remain -= PAGE_SIZE;
122 }
123 if (remain == 0)
124 goto out;
125
126 n = do_op_one_page(addr, remain, is_write, op, arg);
127 if (n != 0) {
128 remain = (n < 0 ? remain : 0);
129 goto out;
130 }
131
132 return 0;
133 out:
134 return remain;
135}
136
137static int copy_chunk_from_user(unsigned long from, int len, void *arg)
138{
139 unsigned long *to_ptr = arg, to = *to_ptr;
140
141 memcpy((void *) to, (void *) from, len);
142 *to_ptr += len;
143 return 0;
144}
145
146unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n)
147{
148 if (uaccess_kernel()) {
149 memcpy(to, (__force void*)from, n);
150 return 0;
151 }
152
153 return buffer_op((unsigned long) from, n, 0, copy_chunk_from_user, &to);
154}
155EXPORT_SYMBOL(raw_copy_from_user);
156
157static int copy_chunk_to_user(unsigned long to, int len, void *arg)
158{
159 unsigned long *from_ptr = arg, from = *from_ptr;
160
161 memcpy((void *) to, (void *) from, len);
162 *from_ptr += len;
163 return 0;
164}
165
166unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n)
167{
168 if (uaccess_kernel()) {
169 memcpy((__force void *) to, from, n);
170 return 0;
171 }
172
173 return buffer_op((unsigned long) to, n, 1, copy_chunk_to_user, &from);
174}
175EXPORT_SYMBOL(raw_copy_to_user);
176
177static int strncpy_chunk_from_user(unsigned long from, int len, void *arg)
178{
179 char **to_ptr = arg, *to = *to_ptr;
180 int n;
181
182 strncpy(to, (void *) from, len);
183 n = strnlen(to, len);
184 *to_ptr += n;
185
186 if (n < len)
187 return 1;
188 return 0;
189}
190
191long __strncpy_from_user(char *dst, const char __user *src, long count)
192{
193 long n;
194 char *ptr = dst;
195
196 if (uaccess_kernel()) {
197 strncpy(dst, (__force void *) src, count);
198 return strnlen(dst, count);
199 }
200
201 n = buffer_op((unsigned long) src, count, 0, strncpy_chunk_from_user,
202 &ptr);
203 if (n != 0)
204 return -EFAULT;
205 return strnlen(dst, count);
206}
207EXPORT_SYMBOL(__strncpy_from_user);
208
209static int clear_chunk(unsigned long addr, int len, void *unused)
210{
211 memset((void *) addr, 0, len);
212 return 0;
213}
214
215unsigned long __clear_user(void __user *mem, unsigned long len)
216{
217 if (uaccess_kernel()) {
218 memset((__force void*)mem, 0, len);
219 return 0;
220 }
221
222 return buffer_op((unsigned long) mem, len, 1, clear_chunk, NULL);
223}
224EXPORT_SYMBOL(__clear_user);
225
226static int strnlen_chunk(unsigned long str, int len, void *arg)
227{
228 int *len_ptr = arg, n;
229
230 n = strnlen((void *) str, len);
231 *len_ptr += n;
232
233 if (n < len)
234 return 1;
235 return 0;
236}
237
238long __strnlen_user(const void __user *str, long len)
239{
240 int count = 0, n;
241
242 if (uaccess_kernel())
243 return strnlen((__force char*)str, len) + 1;
244
245 n = buffer_op((unsigned long) str, len, 0, strnlen_chunk, &count);
246 if (n == 0)
247 return count + 1;
248 return 0;
249}
250EXPORT_SYMBOL(__strnlen_user);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 */
5
6#include <linux/err.h>
7#include <linux/highmem.h>
8#include <linux/mm.h>
9#include <linux/module.h>
10#include <linux/sched.h>
11#include <asm/current.h>
12#include <asm/page.h>
13#include <kern_util.h>
14#include <asm/futex.h>
15#include <os.h>
16
17pte_t *virt_to_pte(struct mm_struct *mm, unsigned long addr)
18{
19 pgd_t *pgd;
20 p4d_t *p4d;
21 pud_t *pud;
22 pmd_t *pmd;
23
24 if (mm == NULL)
25 return NULL;
26
27 pgd = pgd_offset(mm, addr);
28 if (!pgd_present(*pgd))
29 return NULL;
30
31 p4d = p4d_offset(pgd, addr);
32 if (!p4d_present(*p4d))
33 return NULL;
34
35 pud = pud_offset(p4d, addr);
36 if (!pud_present(*pud))
37 return NULL;
38
39 pmd = pmd_offset(pud, addr);
40 if (!pmd_present(*pmd))
41 return NULL;
42
43 return pte_offset_kernel(pmd, addr);
44}
45
46static pte_t *maybe_map(unsigned long virt, int is_write)
47{
48 pte_t *pte = virt_to_pte(current->mm, virt);
49 int err, dummy_code;
50
51 if ((pte == NULL) || !pte_present(*pte) ||
52 (is_write && !pte_write(*pte))) {
53 err = handle_page_fault(virt, 0, is_write, 1, &dummy_code);
54 if (err)
55 return NULL;
56 pte = virt_to_pte(current->mm, virt);
57 }
58 if (!pte_present(*pte))
59 pte = NULL;
60
61 return pte;
62}
63
64static int do_op_one_page(unsigned long addr, int len, int is_write,
65 int (*op)(unsigned long addr, int len, void *arg), void *arg)
66{
67 struct page *page;
68 pte_t *pte;
69 int n;
70
71 pte = maybe_map(addr, is_write);
72 if (pte == NULL)
73 return -1;
74
75 page = pte_page(*pte);
76#ifdef CONFIG_64BIT
77 pagefault_disable();
78 addr = (unsigned long) page_address(page) +
79 (addr & ~PAGE_MASK);
80#else
81 addr = (unsigned long) kmap_atomic(page) +
82 (addr & ~PAGE_MASK);
83#endif
84 n = (*op)(addr, len, arg);
85
86#ifdef CONFIG_64BIT
87 pagefault_enable();
88#else
89 kunmap_atomic((void *)addr);
90#endif
91
92 return n;
93}
94
95static long buffer_op(unsigned long addr, int len, int is_write,
96 int (*op)(unsigned long, int, void *), void *arg)
97{
98 long size, remain, n;
99
100 size = min(PAGE_ALIGN(addr) - addr, (unsigned long) len);
101 remain = len;
102
103 n = do_op_one_page(addr, size, is_write, op, arg);
104 if (n != 0) {
105 remain = (n < 0 ? remain : 0);
106 goto out;
107 }
108
109 addr += size;
110 remain -= size;
111 if (remain == 0)
112 goto out;
113
114 while (addr < ((addr + remain) & PAGE_MASK)) {
115 n = do_op_one_page(addr, PAGE_SIZE, is_write, op, arg);
116 if (n != 0) {
117 remain = (n < 0 ? remain : 0);
118 goto out;
119 }
120
121 addr += PAGE_SIZE;
122 remain -= PAGE_SIZE;
123 }
124 if (remain == 0)
125 goto out;
126
127 n = do_op_one_page(addr, remain, is_write, op, arg);
128 if (n != 0) {
129 remain = (n < 0 ? remain : 0);
130 goto out;
131 }
132
133 return 0;
134 out:
135 return remain;
136}
137
138static int copy_chunk_from_user(unsigned long from, int len, void *arg)
139{
140 unsigned long *to_ptr = arg, to = *to_ptr;
141
142 memcpy((void *) to, (void *) from, len);
143 *to_ptr += len;
144 return 0;
145}
146
147unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n)
148{
149 return buffer_op((unsigned long) from, n, 0, copy_chunk_from_user, &to);
150}
151EXPORT_SYMBOL(raw_copy_from_user);
152
153static int copy_chunk_to_user(unsigned long to, int len, void *arg)
154{
155 unsigned long *from_ptr = arg, from = *from_ptr;
156
157 memcpy((void *) to, (void *) from, len);
158 *from_ptr += len;
159 return 0;
160}
161
162unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n)
163{
164 return buffer_op((unsigned long) to, n, 1, copy_chunk_to_user, &from);
165}
166EXPORT_SYMBOL(raw_copy_to_user);
167
168static int strncpy_chunk_from_user(unsigned long from, int len, void *arg)
169{
170 char **to_ptr = arg, *to = *to_ptr;
171 int n;
172
173 strncpy(to, (void *) from, len);
174 n = strnlen(to, len);
175 *to_ptr += n;
176
177 if (n < len)
178 return 1;
179 return 0;
180}
181
182long strncpy_from_user(char *dst, const char __user *src, long count)
183{
184 long n;
185 char *ptr = dst;
186
187 if (!access_ok(src, 1))
188 return -EFAULT;
189 n = buffer_op((unsigned long) src, count, 0, strncpy_chunk_from_user,
190 &ptr);
191 if (n != 0)
192 return -EFAULT;
193 return strnlen(dst, count);
194}
195EXPORT_SYMBOL(strncpy_from_user);
196
197static int clear_chunk(unsigned long addr, int len, void *unused)
198{
199 memset((void *) addr, 0, len);
200 return 0;
201}
202
203unsigned long __clear_user(void __user *mem, unsigned long len)
204{
205 return buffer_op((unsigned long) mem, len, 1, clear_chunk, NULL);
206}
207EXPORT_SYMBOL(__clear_user);
208
209static int strnlen_chunk(unsigned long str, int len, void *arg)
210{
211 int *len_ptr = arg, n;
212
213 n = strnlen((void *) str, len);
214 *len_ptr += n;
215
216 if (n < len)
217 return 1;
218 return 0;
219}
220
221long strnlen_user(const char __user *str, long len)
222{
223 int count = 0, n;
224
225 if (!access_ok(str, 1))
226 return -EFAULT;
227 n = buffer_op((unsigned long) str, len, 0, strnlen_chunk, &count);
228 if (n == 0)
229 return count + 1;
230 return 0;
231}
232EXPORT_SYMBOL(strnlen_user);
233
234/**
235 * arch_futex_atomic_op_inuser() - Atomic arithmetic operation with constant
236 * argument and comparison of the previous
237 * futex value with another constant.
238 *
239 * @op: operation to execute
240 * @oparg: argument to operation
241 * @oval: old value at uaddr
242 * @uaddr: pointer to user space address
243 *
244 * Return:
245 * 0 - On success
246 * -EFAULT - User access resulted in a page fault
247 * -EAGAIN - Atomic operation was unable to complete due to contention
248 * -ENOSYS - Operation not supported
249 */
250
251int arch_futex_atomic_op_inuser(int op, u32 oparg, int *oval, u32 __user *uaddr)
252{
253 int oldval, ret;
254 struct page *page;
255 unsigned long addr = (unsigned long) uaddr;
256 pte_t *pte;
257
258 ret = -EFAULT;
259 if (!access_ok(uaddr, sizeof(*uaddr)))
260 return -EFAULT;
261 preempt_disable();
262 pte = maybe_map(addr, 1);
263 if (pte == NULL)
264 goto out_inuser;
265
266 page = pte_page(*pte);
267#ifdef CONFIG_64BIT
268 pagefault_disable();
269 addr = (unsigned long) page_address(page) +
270 (((unsigned long) addr) & ~PAGE_MASK);
271#else
272 addr = (unsigned long) kmap_atomic(page) +
273 ((unsigned long) addr & ~PAGE_MASK);
274#endif
275 uaddr = (u32 *) addr;
276 oldval = *uaddr;
277
278 ret = 0;
279
280 switch (op) {
281 case FUTEX_OP_SET:
282 *uaddr = oparg;
283 break;
284 case FUTEX_OP_ADD:
285 *uaddr += oparg;
286 break;
287 case FUTEX_OP_OR:
288 *uaddr |= oparg;
289 break;
290 case FUTEX_OP_ANDN:
291 *uaddr &= ~oparg;
292 break;
293 case FUTEX_OP_XOR:
294 *uaddr ^= oparg;
295 break;
296 default:
297 ret = -ENOSYS;
298 }
299#ifdef CONFIG_64BIT
300 pagefault_enable();
301#else
302 kunmap_atomic((void *)addr);
303#endif
304
305out_inuser:
306 preempt_enable();
307
308 if (ret == 0)
309 *oval = oldval;
310
311 return ret;
312}
313EXPORT_SYMBOL(arch_futex_atomic_op_inuser);
314
315/**
316 * futex_atomic_cmpxchg_inatomic() - Compare and exchange the content of the
317 * uaddr with newval if the current value is
318 * oldval.
319 * @uval: pointer to store content of @uaddr
320 * @uaddr: pointer to user space address
321 * @oldval: old value
322 * @newval: new value to store to @uaddr
323 *
324 * Return:
325 * 0 - On success
326 * -EFAULT - User access resulted in a page fault
327 * -EAGAIN - Atomic operation was unable to complete due to contention
328 */
329
330int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
331 u32 oldval, u32 newval)
332{
333 struct page *page;
334 pte_t *pte;
335 int ret = -EFAULT;
336
337 if (!access_ok(uaddr, sizeof(*uaddr)))
338 return -EFAULT;
339
340 preempt_disable();
341 pte = maybe_map((unsigned long) uaddr, 1);
342 if (pte == NULL)
343 goto out_inatomic;
344
345 page = pte_page(*pte);
346#ifdef CONFIG_64BIT
347 pagefault_disable();
348 uaddr = page_address(page) + (((unsigned long) uaddr) & ~PAGE_MASK);
349#else
350 uaddr = kmap_atomic(page) + ((unsigned long) uaddr & ~PAGE_MASK);
351#endif
352
353 *uval = *uaddr;
354
355 ret = cmpxchg(uaddr, oldval, newval);
356
357#ifdef CONFIG_64BIT
358 pagefault_enable();
359#else
360 kunmap_atomic(uaddr);
361#endif
362 ret = 0;
363
364out_inatomic:
365 preempt_enable();
366 return ret;
367}
368EXPORT_SYMBOL(futex_atomic_cmpxchg_inatomic);