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Linux/arch/ia64/include/asm/uaccess.h

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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/page-flags.h>
 37 #include <linux/mm.h>
 38 
 39 #include <asm/intrinsics.h>
 40 #include <asm/pgtable.h>
 41 #include <asm/io.h>
 42 #include <asm/extable.h>
 43 
 44 /*
 45  * For historical reasons, the following macros are grossly misnamed:
 46  */
 47 #define KERNEL_DS       ((mm_segment_t) { ~0UL })               /* cf. access_ok() */
 48 #define USER_DS         ((mm_segment_t) { TASK_SIZE-1 })        /* cf. access_ok() */
 49 
 50 #define get_ds()  (KERNEL_DS)
 51 #define get_fs()  (current_thread_info()->addr_limit)
 52 #define set_fs(x) (current_thread_info()->addr_limit = (x))
 53 
 54 #define segment_eq(a, b)        ((a).seg == (b).seg)
 55 
 56 /*
 57  * When accessing user memory, we need to make sure the entire area really is in
 58  * user-level space.  In order to do this efficiently, we make sure that the page at
 59  * address TASK_SIZE is never valid.  We also need to make sure that the address doesn't
 60  * point inside the virtually mapped linear page table.
 61  */
 62 static inline int __access_ok(const void __user *p, unsigned long size)
 63 {
 64         unsigned long addr = (unsigned long)p;
 65         unsigned long seg = get_fs().seg;
 66         return likely(addr <= seg) &&
 67          (seg == KERNEL_DS.seg || likely(REGION_OFFSET(addr) < RGN_MAP_LIMIT));
 68 }
 69 #define access_ok(type, addr, size)     __access_ok((addr), (size))
 70 
 71 /*
 72  * These are the main single-value transfer routines.  They automatically
 73  * use the right size if we just have the right pointer type.
 74  *
 75  * Careful to not
 76  * (a) re-use the arguments for side effects (sizeof/typeof is ok)
 77  * (b) require any knowledge of processes at this stage
 78  */
 79 #define put_user(x, ptr)        __put_user_check((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr)))
 80 #define get_user(x, ptr)        __get_user_check((x), (ptr), sizeof(*(ptr)))
 81 
 82 /*
 83  * The "__xxx" versions do not do address space checking, useful when
 84  * doing multiple accesses to the same area (the programmer has to do the
 85  * checks by hand with "access_ok()")
 86  */
 87 #define __put_user(x, ptr)      __put_user_nocheck((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr)))
 88 #define __get_user(x, ptr)      __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 89 
 90 extern long __put_user_unaligned_unknown (void);
 91 
 92 #define __put_user_unaligned(x, ptr)                                                            \
 93 ({                                                                                              \
 94         long __ret;                                                                             \
 95         switch (sizeof(*(ptr))) {                                                               \
 96                 case 1: __ret = __put_user((x), (ptr)); break;                                  \
 97                 case 2: __ret = (__put_user((x), (u8 __user *)(ptr)))                           \
 98                         | (__put_user((x) >> 8, ((u8 __user *)(ptr) + 1))); break;              \
 99                 case 4: __ret = (__put_user((x), (u16 __user *)(ptr)))                          \
100                         | (__put_user((x) >> 16, ((u16 __user *)(ptr) + 1))); break;            \
101                 case 8: __ret = (__put_user((x), (u32 __user *)(ptr)))                          \
102                         | (__put_user((x) >> 32, ((u32 __user *)(ptr) + 1))); break;            \
103                 default: __ret = __put_user_unaligned_unknown();                                \
104         }                                                                                       \
105         __ret;                                                                                  \
106 })
107 
108 extern long __get_user_unaligned_unknown (void);
109 
110 #define __get_user_unaligned(x, ptr)                                                            \
111 ({                                                                                              \
112         long __ret;                                                                             \
113         switch (sizeof(*(ptr))) {                                                               \
114                 case 1: __ret = __get_user((x), (ptr)); break;                                  \
115                 case 2: __ret = (__get_user((x), (u8 __user *)(ptr)))                           \
116                         | (__get_user((x) >> 8, ((u8 __user *)(ptr) + 1))); break;              \
117                 case 4: __ret = (__get_user((x), (u16 __user *)(ptr)))                          \
118                         | (__get_user((x) >> 16, ((u16 __user *)(ptr) + 1))); break;            \
119                 case 8: __ret = (__get_user((x), (u32 __user *)(ptr)))                          \
120                         | (__get_user((x) >> 32, ((u32 __user *)(ptr) + 1))); break;            \
121                 default: __ret = __get_user_unaligned_unknown();                                \
122         }                                                                                       \
123         __ret;                                                                                  \
124 })
125 
126 #ifdef ASM_SUPPORTED
127   struct __large_struct { unsigned long buf[100]; };
128 # define __m(x) (*(struct __large_struct __user *)(x))
129 
130 /* We need to declare the __ex_table section before we can use it in .xdata.  */
131 asm (".section \"__ex_table\", \"a\"\n\t.previous");
132 
133 # define __get_user_size(val, addr, n, err)                                                     \
134 do {                                                                                            \
135         register long __gu_r8 asm ("r8") = 0;                                                   \
136         register long __gu_r9 asm ("r9");                                                       \
137         asm ("\n[1:]\tld"#n" %0=%2%P2\t// %0 and %1 get overwritten by exception handler\n"     \
138              "\t.xdata4 \"__ex_table\", 1b-., 1f-.+4\n"                                         \
139              "[1:]"                                                                             \
140              : "=r"(__gu_r9), "=r"(__gu_r8) : "m"(__m(addr)), "1"(__gu_r8));                    \
141         (err) = __gu_r8;                                                                        \
142         (val) = __gu_r9;                                                                        \
143 } while (0)
144 
145 /*
146  * The "__put_user_size()" macro tells gcc it reads from memory instead of writing it.  This
147  * is because they do not write to any memory gcc knows about, so there are no aliasing
148  * issues.
149  */
150 # define __put_user_size(val, addr, n, err)                                                     \
151 do {                                                                                            \
152         register long __pu_r8 asm ("r8") = 0;                                                   \
153         asm volatile ("\n[1:]\tst"#n" %1=%r2%P1\t// %0 gets overwritten by exception handler\n" \
154                       "\t.xdata4 \"__ex_table\", 1b-., 1f-.\n"                                  \
155                       "[1:]"                                                                    \
156                       : "=r"(__pu_r8) : "m"(__m(addr)), "rO"(val), ""(__pu_r8));               \
157         (err) = __pu_r8;                                                                        \
158 } while (0)
159 
160 #else /* !ASM_SUPPORTED */
161 # define RELOC_TYPE     2       /* ip-rel */
162 # define __get_user_size(val, addr, n, err)                             \
163 do {                                                                    \
164         __ld_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE);   \
165         (err) = ia64_getreg(_IA64_REG_R8);                              \
166         (val) = ia64_getreg(_IA64_REG_R9);                              \
167 } while (0)
168 # define __put_user_size(val, addr, n, err)                             \
169 do {                                                                    \
170         __st_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE,    \
171                   (__force unsigned long) (val));                       \
172         (err) = ia64_getreg(_IA64_REG_R8);                              \
173 } while (0)
174 #endif /* !ASM_SUPPORTED */
175 
176 extern void __get_user_unknown (void);
177 
178 /*
179  * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which
180  * could clobber r8 and r9 (among others).  Thus, be careful not to evaluate it while
181  * using r8/r9.
182  */
183 #define __do_get_user(check, x, ptr, size)                                              \
184 ({                                                                                      \
185         const __typeof__(*(ptr)) __user *__gu_ptr = (ptr);                              \
186         __typeof__ (size) __gu_size = (size);                                           \
187         long __gu_err = -EFAULT;                                                        \
188         unsigned long __gu_val = 0;                                                     \
189         if (!check || __access_ok(__gu_ptr, size))                                      \
190                 switch (__gu_size) {                                                    \
191                       case 1: __get_user_size(__gu_val, __gu_ptr, 1, __gu_err); break;  \
192                       case 2: __get_user_size(__gu_val, __gu_ptr, 2, __gu_err); break;  \
193                       case 4: __get_user_size(__gu_val, __gu_ptr, 4, __gu_err); break;  \
194                       case 8: __get_user_size(__gu_val, __gu_ptr, 8, __gu_err); break;  \
195                       default: __get_user_unknown(); break;                             \
196                 }                                                                       \
197         (x) = (__force __typeof__(*(__gu_ptr))) __gu_val;                               \
198         __gu_err;                                                                       \
199 })
200 
201 #define __get_user_nocheck(x, ptr, size)        __do_get_user(0, x, ptr, size)
202 #define __get_user_check(x, ptr, size)  __do_get_user(1, x, ptr, size)
203 
204 extern void __put_user_unknown (void);
205 
206 /*
207  * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which
208  * could clobber r8 (among others).  Thus, be careful not to evaluate them while using r8.
209  */
210 #define __do_put_user(check, x, ptr, size)                                              \
211 ({                                                                                      \
212         __typeof__ (x) __pu_x = (x);                                                    \
213         __typeof__ (*(ptr)) __user *__pu_ptr = (ptr);                                   \
214         __typeof__ (size) __pu_size = (size);                                           \
215         long __pu_err = -EFAULT;                                                        \
216                                                                                         \
217         if (!check || __access_ok(__pu_ptr, __pu_size))                                 \
218                 switch (__pu_size) {                                                    \
219                       case 1: __put_user_size(__pu_x, __pu_ptr, 1, __pu_err); break;    \
220                       case 2: __put_user_size(__pu_x, __pu_ptr, 2, __pu_err); break;    \
221                       case 4: __put_user_size(__pu_x, __pu_ptr, 4, __pu_err); break;    \
222                       case 8: __put_user_size(__pu_x, __pu_ptr, 8, __pu_err); break;    \
223                       default: __put_user_unknown(); break;                             \
224                 }                                                                       \
225         __pu_err;                                                                       \
226 })
227 
228 #define __put_user_nocheck(x, ptr, size)        __do_put_user(0, x, ptr, size)
229 #define __put_user_check(x, ptr, size)  __do_put_user(1, x, ptr, size)
230 
231 /*
232  * Complex access routines
233  */
234 extern unsigned long __must_check __copy_user (void __user *to, const void __user *from,
235                                                unsigned long count);
236 
237 static inline unsigned long
238 raw_copy_to_user(void __user *to, const void *from, unsigned long count)
239 {
240         return __copy_user(to, (__force void __user *) from, count);
241 }
242 
243 static inline unsigned long
244 raw_copy_from_user(void *to, const void __user *from, unsigned long count)
245 {
246         return __copy_user((__force void __user *) to, from, count);
247 }
248 
249 #define INLINE_COPY_FROM_USER
250 #define INLINE_COPY_TO_USER
251 
252 extern unsigned long __do_clear_user (void __user *, unsigned long);
253 
254 #define __clear_user(to, n)             __do_clear_user(to, n)
255 
256 #define clear_user(to, n)                                       \
257 ({                                                              \
258         unsigned long __cu_len = (n);                           \
259         if (__access_ok(to, __cu_len))                          \
260                 __cu_len = __do_clear_user(to, __cu_len);       \
261         __cu_len;                                               \
262 })
263 
264 
265 /*
266  * Returns: -EFAULT if exception before terminator, N if the entire buffer filled, else
267  * strlen.
268  */
269 extern long __must_check __strncpy_from_user (char *to, const char __user *from, long to_len);
270 
271 #define strncpy_from_user(to, from, n)                                  \
272 ({                                                                      \
273         const char __user * __sfu_from = (from);                        \
274         long __sfu_ret = -EFAULT;                                       \
275         if (__access_ok(__sfu_from, 0))                                 \
276                 __sfu_ret = __strncpy_from_user((to), __sfu_from, (n)); \
277         __sfu_ret;                                                      \
278 })
279 
280 /* Returns: 0 if bad, string length+1 (memory size) of string if ok */
281 extern unsigned long __strlen_user (const char __user *);
282 
283 #define strlen_user(str)                                \
284 ({                                                      \
285         const char __user *__su_str = (str);            \
286         unsigned long __su_ret = 0;                     \
287         if (__access_ok(__su_str, 0))                   \
288                 __su_ret = __strlen_user(__su_str);     \
289         __su_ret;                                       \
290 })
291 
292 /*
293  * Returns: 0 if exception before NUL or reaching the supplied limit
294  * (N), a value greater than N if the limit would be exceeded, else
295  * strlen.
296  */
297 extern unsigned long __strnlen_user (const char __user *, long);
298 
299 #define strnlen_user(str, len)                                  \
300 ({                                                              \
301         const char __user *__su_str = (str);                    \
302         unsigned long __su_ret = 0;                             \
303         if (__access_ok(__su_str, 0))                           \
304                 __su_ret = __strnlen_user(__su_str, len);       \
305         __su_ret;                                               \
306 })
307 
308 #define ARCH_HAS_TRANSLATE_MEM_PTR      1
309 static __inline__ void *
310 xlate_dev_mem_ptr(phys_addr_t p)
311 {
312         struct page *page;
313         void *ptr;
314 
315         page = pfn_to_page(p >> PAGE_SHIFT);
316         if (PageUncached(page))
317                 ptr = (void *)p + __IA64_UNCACHED_OFFSET;
318         else
319                 ptr = __va(p);
320 
321         return ptr;
322 }
323 
324 /*
325  * Convert a virtual cached kernel memory pointer to an uncached pointer
326  */
327 static __inline__ void *
328 xlate_dev_kmem_ptr(void *p)
329 {
330         struct page *page;
331         void *ptr;
332 
333         page = virt_to_page((unsigned long)p);
334         if (PageUncached(page))
335                 ptr = (void *)__pa(p) + __IA64_UNCACHED_OFFSET;
336         else
337                 ptr = p;
338 
339         return ptr;
340 }
341 
342 #endif /* _ASM_IA64_UACCESS_H */
343 

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