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1#ifndef _ASM_IA64_UACCESS_H
2#define _ASM_IA64_UACCESS_H
3
4/*
5 * This file defines various macros to transfer memory areas across
6 * the user/kernel boundary. This needs to be done carefully because
7 * this code is executed in kernel mode and uses user-specified
8 * addresses. Thus, we need to be careful not to let the user to
9 * trick us into accessing kernel memory that would normally be
10 * inaccessible. This code is also fairly performance sensitive,
11 * so we want to spend as little time doing safety checks as
12 * possible.
13 *
14 * To make matters a bit more interesting, these macros sometimes also
15 * called from within the kernel itself, in which case the address
16 * validity check must be skipped. The get_fs() macro tells us what
17 * to do: if get_fs()==USER_DS, checking is performed, if
18 * get_fs()==KERNEL_DS, checking is bypassed.
19 *
20 * Note that even if the memory area specified by the user is in a
21 * valid address range, it is still possible that we'll get a page
22 * fault while accessing it. This is handled by filling out an
23 * exception handler fixup entry for each instruction that has the
24 * potential to fault. When such a fault occurs, the page fault
25 * handler checks to see whether the faulting instruction has a fixup
26 * associated and, if so, sets r8 to -EFAULT and clears r9 to 0 and
27 * then resumes execution at the continuation point.
28 *
29 * Based on <asm-alpha/uaccess.h>.
30 *
31 * Copyright (C) 1998, 1999, 2001-2004 Hewlett-Packard Co
32 * David Mosberger-Tang <davidm@hpl.hp.com>
33 */
34
35#include <linux/compiler.h>
36#include <linux/errno.h>
37#include <linux/sched.h>
38#include <linux/page-flags.h>
39#include <linux/mm.h>
40
41#include <asm/intrinsics.h>
42#include <asm/pgtable.h>
43#include <asm/io.h>
44
45/*
46 * For historical reasons, the following macros are grossly misnamed:
47 */
48#define KERNEL_DS ((mm_segment_t) { ~0UL }) /* cf. access_ok() */
49#define USER_DS ((mm_segment_t) { TASK_SIZE-1 }) /* cf. access_ok() */
50
51#define VERIFY_READ 0
52#define VERIFY_WRITE 1
53
54#define get_ds() (KERNEL_DS)
55#define get_fs() (current_thread_info()->addr_limit)
56#define set_fs(x) (current_thread_info()->addr_limit = (x))
57
58#define segment_eq(a, b) ((a).seg == (b).seg)
59
60/*
61 * When accessing user memory, we need to make sure the entire area really is in
62 * user-level space. In order to do this efficiently, we make sure that the page at
63 * address TASK_SIZE is never valid. We also need to make sure that the address doesn't
64 * point inside the virtually mapped linear page table.
65 */
66#define __access_ok(addr, size, segment) \
67({ \
68 __chk_user_ptr(addr); \
69 (likely((unsigned long) (addr) <= (segment).seg) \
70 && ((segment).seg == KERNEL_DS.seg \
71 || likely(REGION_OFFSET((unsigned long) (addr)) < RGN_MAP_LIMIT))); \
72})
73#define access_ok(type, addr, size) __access_ok((addr), (size), get_fs())
74
75/* this function will go away soon - use access_ok() instead */
76static inline int __deprecated
77verify_area (int type, const void __user *addr, unsigned long size)
78{
79 return access_ok(type, addr, size) ? 0 : -EFAULT;
80}
81
82/*
83 * These are the main single-value transfer routines. They automatically
84 * use the right size if we just have the right pointer type.
85 *
86 * Careful to not
87 * (a) re-use the arguments for side effects (sizeof/typeof is ok)
88 * (b) require any knowledge of processes at this stage
89 */
90#define put_user(x, ptr) __put_user_check((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr)), get_fs())
91#define get_user(x, ptr) __get_user_check((x), (ptr), sizeof(*(ptr)), get_fs())
92
93/*
94 * The "__xxx" versions do not do address space checking, useful when
95 * doing multiple accesses to the same area (the programmer has to do the
96 * checks by hand with "access_ok()")
97 */
98#define __put_user(x, ptr) __put_user_nocheck((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr)))
99#define __get_user(x, ptr) __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
100
101extern long __put_user_unaligned_unknown (void);
102
103#define __put_user_unaligned(x, ptr) \
104({ \
105 long __ret; \
106 switch (sizeof(*(ptr))) { \
107 case 1: __ret = __put_user((x), (ptr)); break; \
108 case 2: __ret = (__put_user((x), (u8 __user *)(ptr))) \
109 | (__put_user((x) >> 8, ((u8 __user *)(ptr) + 1))); break; \
110 case 4: __ret = (__put_user((x), (u16 __user *)(ptr))) \
111 | (__put_user((x) >> 16, ((u16 __user *)(ptr) + 1))); break; \
112 case 8: __ret = (__put_user((x), (u32 __user *)(ptr))) \
113 | (__put_user((x) >> 32, ((u32 __user *)(ptr) + 1))); break; \
114 default: __ret = __put_user_unaligned_unknown(); \
115 } \
116 __ret; \
117})
118
119extern long __get_user_unaligned_unknown (void);
120
121#define __get_user_unaligned(x, ptr) \
122({ \
123 long __ret; \
124 switch (sizeof(*(ptr))) { \
125 case 1: __ret = __get_user((x), (ptr)); break; \
126 case 2: __ret = (__get_user((x), (u8 __user *)(ptr))) \
127 | (__get_user((x) >> 8, ((u8 __user *)(ptr) + 1))); break; \
128 case 4: __ret = (__get_user((x), (u16 __user *)(ptr))) \
129 | (__get_user((x) >> 16, ((u16 __user *)(ptr) + 1))); break; \
130 case 8: __ret = (__get_user((x), (u32 __user *)(ptr))) \
131 | (__get_user((x) >> 32, ((u32 __user *)(ptr) + 1))); break; \
132 default: __ret = __get_user_unaligned_unknown(); \
133 } \
134 __ret; \
135})
136
137#ifdef ASM_SUPPORTED
138 struct __large_struct { unsigned long buf[100]; };
139# define __m(x) (*(struct __large_struct __user *)(x))
140
141/* We need to declare the __ex_table section before we can use it in .xdata. */
142asm (".section \"__ex_table\", \"a\"\n\t.previous");
143
144# define __get_user_size(val, addr, n, err) \
145do { \
146 register long __gu_r8 asm ("r8") = 0; \
147 register long __gu_r9 asm ("r9"); \
148 asm ("\n[1:]\tld"#n" %0=%2%P2\t// %0 and %1 get overwritten by exception handler\n" \
149 "\t.xdata4 \"__ex_table\", 1b-., 1f-.+4\n" \
150 "[1:]" \
151 : "=r"(__gu_r9), "=r"(__gu_r8) : "m"(__m(addr)), "1"(__gu_r8)); \
152 (err) = __gu_r8; \
153 (val) = __gu_r9; \
154} while (0)
155
156/*
157 * The "__put_user_size()" macro tells gcc it reads from memory instead of writing it. This
158 * is because they do not write to any memory gcc knows about, so there are no aliasing
159 * issues.
160 */
161# define __put_user_size(val, addr, n, err) \
162do { \
163 register long __pu_r8 asm ("r8") = 0; \
164 asm volatile ("\n[1:]\tst"#n" %1=%r2%P1\t// %0 gets overwritten by exception handler\n" \
165 "\t.xdata4 \"__ex_table\", 1b-., 1f-.\n" \
166 "[1:]" \
167 : "=r"(__pu_r8) : "m"(__m(addr)), "rO"(val), "0"(__pu_r8)); \
168 (err) = __pu_r8; \
169} while (0)
170
171#else /* !ASM_SUPPORTED */
172# define RELOC_TYPE 2 /* ip-rel */
173# define __get_user_size(val, addr, n, err) \
174do { \
175 __ld_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE); \
176 (err) = ia64_getreg(_IA64_REG_R8); \
177 (val) = ia64_getreg(_IA64_REG_R9); \
178} while (0)
179# define __put_user_size(val, addr, n, err) \
180do { \
181 __st_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE, (unsigned long) (val)); \
182 (err) = ia64_getreg(_IA64_REG_R8); \
183} while (0)
184#endif /* !ASM_SUPPORTED */
185
186extern void __get_user_unknown (void);
187
188/*
189 * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which
190 * could clobber r8 and r9 (among others). Thus, be careful not to evaluate it while
191 * using r8/r9.
192 */
193#define __do_get_user(check, x, ptr, size, segment) \
194({ \
195 const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
196 __typeof__ (size) __gu_size = (size); \
197 long __gu_err = -EFAULT, __gu_val = 0; \
198 \
199 if (!check || __access_ok(__gu_ptr, size, segment)) \
200 switch (__gu_size) { \
201 case 1: __get_user_size(__gu_val, __gu_ptr, 1, __gu_err); break; \
202 case 2: __get_user_size(__gu_val, __gu_ptr, 2, __gu_err); break; \
203 case 4: __get_user_size(__gu_val, __gu_ptr, 4, __gu_err); break; \
204 case 8: __get_user_size(__gu_val, __gu_ptr, 8, __gu_err); break; \
205 default: __get_user_unknown(); break; \
206 } \
207 (x) = (__typeof__(*(__gu_ptr))) __gu_val; \
208 __gu_err; \
209})
210
211#define __get_user_nocheck(x, ptr, size) __do_get_user(0, x, ptr, size, KERNEL_DS)
212#define __get_user_check(x, ptr, size, segment) __do_get_user(1, x, ptr, size, segment)
213
214extern void __put_user_unknown (void);
215
216/*
217 * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which
218 * could clobber r8 (among others). Thus, be careful not to evaluate them while using r8.
219 */
220#define __do_put_user(check, x, ptr, size, segment) \
221({ \
222 __typeof__ (x) __pu_x = (x); \
223 __typeof__ (*(ptr)) __user *__pu_ptr = (ptr); \
224 __typeof__ (size) __pu_size = (size); \
225 long __pu_err = -EFAULT; \
226 \
227 if (!check || __access_ok(__pu_ptr, __pu_size, segment)) \
228 switch (__pu_size) { \
229 case 1: __put_user_size(__pu_x, __pu_ptr, 1, __pu_err); break; \
230 case 2: __put_user_size(__pu_x, __pu_ptr, 2, __pu_err); break; \
231 case 4: __put_user_size(__pu_x, __pu_ptr, 4, __pu_err); break; \
232 case 8: __put_user_size(__pu_x, __pu_ptr, 8, __pu_err); break; \
233 default: __put_user_unknown(); break; \
234 } \
235 __pu_err; \
236})
237
238#define __put_user_nocheck(x, ptr, size) __do_put_user(0, x, ptr, size, KERNEL_DS)
239#define __put_user_check(x, ptr, size, segment) __do_put_user(1, x, ptr, size, segment)
240
241/*
242 * Complex access routines
243 */
244extern unsigned long __must_check __copy_user (void __user *to, const void __user *from,
245 unsigned long count);
246
247static inline unsigned long
248__copy_to_user (void __user *to, const void *from, unsigned long count)
249{
250 return __copy_user(to, (void __user *) from, count);
251}
252
253static inline unsigned long
254__copy_from_user (void *to, const void __user *from, unsigned long count)
255{
256 return __copy_user((void __user *) to, from, count);
257}
258
259#define __copy_to_user_inatomic __copy_to_user
260#define __copy_from_user_inatomic __copy_from_user
261#define copy_to_user(to, from, n) \
262({ \
263 void __user *__cu_to = (to); \
264 const void *__cu_from = (from); \
265 long __cu_len = (n); \
266 \
267 if (__access_ok(__cu_to, __cu_len, get_fs())) \
268 __cu_len = __copy_user(__cu_to, (void __user *) __cu_from, __cu_len); \
269 __cu_len; \
270})
271
272#define copy_from_user(to, from, n) \
273({ \
274 void *__cu_to = (to); \
275 const void __user *__cu_from = (from); \
276 long __cu_len = (n); \
277 \
278 __chk_user_ptr(__cu_from); \
279 if (__access_ok(__cu_from, __cu_len, get_fs())) \
280 __cu_len = __copy_user((void __user *) __cu_to, __cu_from, __cu_len); \
281 __cu_len; \
282})
283
284#define __copy_in_user(to, from, size) __copy_user((to), (from), (size))
285
286static inline unsigned long
287copy_in_user (void __user *to, const void __user *from, unsigned long n)
288{
289 if (likely(access_ok(VERIFY_READ, from, n) && access_ok(VERIFY_WRITE, to, n)))
290 n = __copy_user(to, from, n);
291 return n;
292}
293
294extern unsigned long __do_clear_user (void __user *, unsigned long);
295
296#define __clear_user(to, n) __do_clear_user(to, n)
297
298#define clear_user(to, n) \
299({ \
300 unsigned long __cu_len = (n); \
301 if (__access_ok(to, __cu_len, get_fs())) \
302 __cu_len = __do_clear_user(to, __cu_len); \
303 __cu_len; \
304})
305
306
307/*
308 * Returns: -EFAULT if exception before terminator, N if the entire buffer filled, else
309 * strlen.
310 */
311extern long __must_check __strncpy_from_user (char *to, const char __user *from, long to_len);
312
313#define strncpy_from_user(to, from, n) \
314({ \
315 const char __user * __sfu_from = (from); \
316 long __sfu_ret = -EFAULT; \
317 if (__access_ok(__sfu_from, 0, get_fs())) \
318 __sfu_ret = __strncpy_from_user((to), __sfu_from, (n)); \
319 __sfu_ret; \
320})
321
322/* Returns: 0 if bad, string length+1 (memory size) of string if ok */
323extern unsigned long __strlen_user (const char __user *);
324
325#define strlen_user(str) \
326({ \
327 const char __user *__su_str = (str); \
328 unsigned long __su_ret = 0; \
329 if (__access_ok(__su_str, 0, get_fs())) \
330 __su_ret = __strlen_user(__su_str); \
331 __su_ret; \
332})
333
334/*
335 * Returns: 0 if exception before NUL or reaching the supplied limit
336 * (N), a value greater than N if the limit would be exceeded, else
337 * strlen.
338 */
339extern unsigned long __strnlen_user (const char __user *, long);
340
341#define strnlen_user(str, len) \
342({ \
343 const char __user *__su_str = (str); \
344 unsigned long __su_ret = 0; \
345 if (__access_ok(__su_str, 0, get_fs())) \
346 __su_ret = __strnlen_user(__su_str, len); \
347 __su_ret; \
348})
349
350/* Generic code can't deal with the location-relative format that we use for compactness. */
351#define ARCH_HAS_SORT_EXTABLE
352#define ARCH_HAS_SEARCH_EXTABLE
353
354struct exception_table_entry {
355 int addr; /* location-relative address of insn this fixup is for */
356 int cont; /* location-relative continuation addr.; if bit 2 is set, r9 is set to 0 */
357};
358
359extern void ia64_handle_exception (struct pt_regs *regs, const struct exception_table_entry *e);
360extern const struct exception_table_entry *search_exception_tables (unsigned long addr);
361
362static inline int
363ia64_done_with_exception (struct pt_regs *regs)
364{
365 const struct exception_table_entry *e;
366 e = search_exception_tables(regs->cr_iip + ia64_psr(regs)->ri);
367 if (e) {
368 ia64_handle_exception(regs, e);
369 return 1;
370 }
371 return 0;
372}
373
374#define ARCH_HAS_TRANSLATE_MEM_PTR 1
375static __inline__ char *
376xlate_dev_mem_ptr (unsigned long p)
377{
378 struct page *page;
379 char * ptr;
380
381 page = pfn_to_page(p >> PAGE_SHIFT);
382 if (PageUncached(page))
383 ptr = (char *)p + __IA64_UNCACHED_OFFSET;
384 else
385 ptr = __va(p);
386
387 return ptr;
388}
389
390/*
391 * Convert a virtual cached kernel memory pointer to an uncached pointer
392 */
393static __inline__ char *
394xlate_dev_kmem_ptr (char * p)
395{
396 struct page *page;
397 char * ptr;
398
399 page = virt_to_page((unsigned long)p >> PAGE_SHIFT);
400 if (PageUncached(page))
401 ptr = (char *)__pa(p) + __IA64_UNCACHED_OFFSET;
402 else
403 ptr = p;
404
405 return ptr;
406}
407
408#endif /* _ASM_IA64_UACCESS_H */
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