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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/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 /*
 76  * These are the main single-value transfer routines.  They automatically
 77  * use the right size if we just have the right pointer type.
 78  *
 79  * Careful to not
 80  * (a) re-use the arguments for side effects (sizeof/typeof is ok)
 81  * (b) require any knowledge of processes at this stage
 82  */
 83 #define put_user(x, ptr)        __put_user_check((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr)), get_fs())
 84 #define get_user(x, ptr)        __get_user_check((x), (ptr), sizeof(*(ptr)), get_fs())
 85 
 86 /*
 87  * The "__xxx" versions do not do address space checking, useful when
 88  * doing multiple accesses to the same area (the programmer has to do the
 89  * checks by hand with "access_ok()")
 90  */
 91 #define __put_user(x, ptr)      __put_user_nocheck((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr)))
 92 #define __get_user(x, ptr)      __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 93 
 94 extern long __put_user_unaligned_unknown (void);
 95 
 96 #define __put_user_unaligned(x, ptr)                                                            \
 97 ({                                                                                              \
 98         long __ret;                                                                             \
 99         switch (sizeof(*(ptr))) {                                                               \
100                 case 1: __ret = __put_user((x), (ptr)); break;                                  \
101                 case 2: __ret = (__put_user((x), (u8 __user *)(ptr)))                           \
102                         | (__put_user((x) >> 8, ((u8 __user *)(ptr) + 1))); break;              \
103                 case 4: __ret = (__put_user((x), (u16 __user *)(ptr)))                          \
104                         | (__put_user((x) >> 16, ((u16 __user *)(ptr) + 1))); break;            \
105                 case 8: __ret = (__put_user((x), (u32 __user *)(ptr)))                          \
106                         | (__put_user((x) >> 32, ((u32 __user *)(ptr) + 1))); break;            \
107                 default: __ret = __put_user_unaligned_unknown();                                \
108         }                                                                                       \
109         __ret;                                                                                  \
110 })
111 
112 extern long __get_user_unaligned_unknown (void);
113 
114 #define __get_user_unaligned(x, ptr)                                                            \
115 ({                                                                                              \
116         long __ret;                                                                             \
117         switch (sizeof(*(ptr))) {                                                               \
118                 case 1: __ret = __get_user((x), (ptr)); break;                                  \
119                 case 2: __ret = (__get_user((x), (u8 __user *)(ptr)))                           \
120                         | (__get_user((x) >> 8, ((u8 __user *)(ptr) + 1))); break;              \
121                 case 4: __ret = (__get_user((x), (u16 __user *)(ptr)))                          \
122                         | (__get_user((x) >> 16, ((u16 __user *)(ptr) + 1))); break;            \
123                 case 8: __ret = (__get_user((x), (u32 __user *)(ptr)))                          \
124                         | (__get_user((x) >> 32, ((u32 __user *)(ptr) + 1))); break;            \
125                 default: __ret = __get_user_unaligned_unknown();                                \
126         }                                                                                       \
127         __ret;                                                                                  \
128 })
129 
130 #ifdef ASM_SUPPORTED
131   struct __large_struct { unsigned long buf[100]; };
132 # define __m(x) (*(struct __large_struct __user *)(x))
133 
134 /* We need to declare the __ex_table section before we can use it in .xdata.  */
135 asm (".section \"__ex_table\", \"a\"\n\t.previous");
136 
137 # define __get_user_size(val, addr, n, err)                                                     \
138 do {                                                                                            \
139         register long __gu_r8 asm ("r8") = 0;                                                   \
140         register long __gu_r9 asm ("r9");                                                       \
141         asm ("\n[1:]\tld"#n" %0=%2%P2\t// %0 and %1 get overwritten by exception handler\n"     \
142              "\t.xdata4 \"__ex_table\", 1b-., 1f-.+4\n"                                         \
143              "[1:]"                                                                             \
144              : "=r"(__gu_r9), "=r"(__gu_r8) : "m"(__m(addr)), "1"(__gu_r8));                    \
145         (err) = __gu_r8;                                                                        \
146         (val) = __gu_r9;                                                                        \
147 } while (0)
148 
149 /*
150  * The "__put_user_size()" macro tells gcc it reads from memory instead of writing it.  This
151  * is because they do not write to any memory gcc knows about, so there are no aliasing
152  * issues.
153  */
154 # define __put_user_size(val, addr, n, err)                                                     \
155 do {                                                                                            \
156         register long __pu_r8 asm ("r8") = 0;                                                   \
157         asm volatile ("\n[1:]\tst"#n" %1=%r2%P1\t// %0 gets overwritten by exception handler\n" \
158                       "\t.xdata4 \"__ex_table\", 1b-., 1f-.\n"                                  \
159                       "[1:]"                                                                    \
160                       : "=r"(__pu_r8) : "m"(__m(addr)), "rO"(val), ""(__pu_r8));               \
161         (err) = __pu_r8;                                                                        \
162 } while (0)
163 
164 #else /* !ASM_SUPPORTED */
165 # define RELOC_TYPE     2       /* ip-rel */
166 # define __get_user_size(val, addr, n, err)                             \
167 do {                                                                    \
168         __ld_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE);   \
169         (err) = ia64_getreg(_IA64_REG_R8);                              \
170         (val) = ia64_getreg(_IA64_REG_R9);                              \
171 } while (0)
172 # define __put_user_size(val, addr, n, err)                             \
173 do {                                                                    \
174         __st_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE,    \
175                   (__force unsigned long) (val));                       \
176         (err) = ia64_getreg(_IA64_REG_R8);                              \
177 } while (0)
178 #endif /* !ASM_SUPPORTED */
179 
180 extern void __get_user_unknown (void);
181 
182 /*
183  * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which
184  * could clobber r8 and r9 (among others).  Thus, be careful not to evaluate it while
185  * using r8/r9.
186  */
187 #define __do_get_user(check, x, ptr, size, segment)                                     \
188 ({                                                                                      \
189         const __typeof__(*(ptr)) __user *__gu_ptr = (ptr);                              \
190         __typeof__ (size) __gu_size = (size);                                           \
191         long __gu_err = -EFAULT;                                                        \
192         unsigned long __gu_val = 0;                                                     \
193         if (!check || __access_ok(__gu_ptr, size, segment))                             \
194                 switch (__gu_size) {                                                    \
195                       case 1: __get_user_size(__gu_val, __gu_ptr, 1, __gu_err); break;  \
196                       case 2: __get_user_size(__gu_val, __gu_ptr, 2, __gu_err); break;  \
197                       case 4: __get_user_size(__gu_val, __gu_ptr, 4, __gu_err); break;  \
198                       case 8: __get_user_size(__gu_val, __gu_ptr, 8, __gu_err); break;  \
199                       default: __get_user_unknown(); break;                             \
200                 }                                                                       \
201         (x) = (__force __typeof__(*(__gu_ptr))) __gu_val;                               \
202         __gu_err;                                                                       \
203 })
204 
205 #define __get_user_nocheck(x, ptr, size)        __do_get_user(0, x, ptr, size, KERNEL_DS)
206 #define __get_user_check(x, ptr, size, segment) __do_get_user(1, x, ptr, size, segment)
207 
208 extern void __put_user_unknown (void);
209 
210 /*
211  * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which
212  * could clobber r8 (among others).  Thus, be careful not to evaluate them while using r8.
213  */
214 #define __do_put_user(check, x, ptr, size, segment)                                     \
215 ({                                                                                      \
216         __typeof__ (x) __pu_x = (x);                                                    \
217         __typeof__ (*(ptr)) __user *__pu_ptr = (ptr);                                   \
218         __typeof__ (size) __pu_size = (size);                                           \
219         long __pu_err = -EFAULT;                                                        \
220                                                                                         \
221         if (!check || __access_ok(__pu_ptr, __pu_size, segment))                        \
222                 switch (__pu_size) {                                                    \
223                       case 1: __put_user_size(__pu_x, __pu_ptr, 1, __pu_err); break;    \
224                       case 2: __put_user_size(__pu_x, __pu_ptr, 2, __pu_err); break;    \
225                       case 4: __put_user_size(__pu_x, __pu_ptr, 4, __pu_err); break;    \
226                       case 8: __put_user_size(__pu_x, __pu_ptr, 8, __pu_err); break;    \
227                       default: __put_user_unknown(); break;                             \
228                 }                                                                       \
229         __pu_err;                                                                       \
230 })
231 
232 #define __put_user_nocheck(x, ptr, size)        __do_put_user(0, x, ptr, size, KERNEL_DS)
233 #define __put_user_check(x, ptr, size, segment) __do_put_user(1, x, ptr, size, segment)
234 
235 /*
236  * Complex access routines
237  */
238 extern unsigned long __must_check __copy_user (void __user *to, const void __user *from,
239                                                unsigned long count);
240 
241 static inline unsigned long
242 __copy_to_user (void __user *to, const void *from, unsigned long count)
243 {
244         check_object_size(from, count, true);
245 
246         return __copy_user(to, (__force void __user *) from, count);
247 }
248 
249 static inline unsigned long
250 __copy_from_user (void *to, const void __user *from, unsigned long count)
251 {
252         check_object_size(to, count, false);
253 
254         return __copy_user((__force void __user *) to, from, count);
255 }
256 
257 #define __copy_to_user_inatomic         __copy_to_user
258 #define __copy_from_user_inatomic       __copy_from_user
259 #define copy_to_user(to, from, n)                                                       \
260 ({                                                                                      \
261         void __user *__cu_to = (to);                                                    \
262         const void *__cu_from = (from);                                                 \
263         long __cu_len = (n);                                                            \
264                                                                                         \
265         if (__access_ok(__cu_to, __cu_len, get_fs())) {                                 \
266                 check_object_size(__cu_from, __cu_len, true);                   \
267                 __cu_len = __copy_user(__cu_to, (__force void __user *)  __cu_from, __cu_len);  \
268         }                                                                               \
269         __cu_len;                                                                       \
270 })
271 
272 static inline unsigned long
273 copy_from_user(void *to, const void __user *from, unsigned long n)
274 {
275         check_object_size(to, n, false);
276         if (likely(__access_ok(from, n, get_fs())))
277                 n = __copy_user((__force void __user *) to, from, n);
278         else
279                 memset(to, 0, n);
280         return n;
281 }
282 
283 #define __copy_in_user(to, from, size)  __copy_user((to), (from), (size))
284 
285 static inline unsigned long
286 copy_in_user (void __user *to, const void __user *from, unsigned long n)
287 {
288         if (likely(access_ok(VERIFY_READ, from, n) && access_ok(VERIFY_WRITE, to, n)))
289                 n = __copy_user(to, from, n);
290         return n;
291 }
292 
293 extern unsigned long __do_clear_user (void __user *, unsigned long);
294 
295 #define __clear_user(to, n)             __do_clear_user(to, n)
296 
297 #define clear_user(to, n)                                       \
298 ({                                                              \
299         unsigned long __cu_len = (n);                           \
300         if (__access_ok(to, __cu_len, get_fs()))                \
301                 __cu_len = __do_clear_user(to, __cu_len);       \
302         __cu_len;                                               \
303 })
304 
305 
306 /*
307  * Returns: -EFAULT if exception before terminator, N if the entire buffer filled, else
308  * strlen.
309  */
310 extern long __must_check __strncpy_from_user (char *to, const char __user *from, long to_len);
311 
312 #define strncpy_from_user(to, from, n)                                  \
313 ({                                                                      \
314         const char __user * __sfu_from = (from);                        \
315         long __sfu_ret = -EFAULT;                                       \
316         if (__access_ok(__sfu_from, 0, get_fs()))                       \
317                 __sfu_ret = __strncpy_from_user((to), __sfu_from, (n)); \
318         __sfu_ret;                                                      \
319 })
320 
321 /* Returns: 0 if bad, string length+1 (memory size) of string if ok */
322 extern unsigned long __strlen_user (const char __user *);
323 
324 #define strlen_user(str)                                \
325 ({                                                      \
326         const char __user *__su_str = (str);            \
327         unsigned long __su_ret = 0;                     \
328         if (__access_ok(__su_str, 0, get_fs()))         \
329                 __su_ret = __strlen_user(__su_str);     \
330         __su_ret;                                       \
331 })
332 
333 /*
334  * Returns: 0 if exception before NUL or reaching the supplied limit
335  * (N), a value greater than N if the limit would be exceeded, else
336  * strlen.
337  */
338 extern unsigned long __strnlen_user (const char __user *, long);
339 
340 #define strnlen_user(str, len)                                  \
341 ({                                                              \
342         const char __user *__su_str = (str);                    \
343         unsigned long __su_ret = 0;                             \
344         if (__access_ok(__su_str, 0, get_fs()))                 \
345                 __su_ret = __strnlen_user(__su_str, len);       \
346         __su_ret;                                               \
347 })
348 
349 #define ARCH_HAS_RELATIVE_EXTABLE
350 
351 struct exception_table_entry {
352         int insn;       /* location-relative address of insn this fixup is for */
353         int fixup;      /* location-relative continuation addr.; if bit 2 is set, r9 is set to 0 */
354 };
355 
356 extern void ia64_handle_exception (struct pt_regs *regs, const struct exception_table_entry *e);
357 extern const struct exception_table_entry *search_exception_tables (unsigned long addr);
358 
359 static inline int
360 ia64_done_with_exception (struct pt_regs *regs)
361 {
362         const struct exception_table_entry *e;
363         e = search_exception_tables(regs->cr_iip + ia64_psr(regs)->ri);
364         if (e) {
365                 ia64_handle_exception(regs, e);
366                 return 1;
367         }
368         return 0;
369 }
370 
371 #define ARCH_HAS_TRANSLATE_MEM_PTR      1
372 static __inline__ void *
373 xlate_dev_mem_ptr(phys_addr_t p)
374 {
375         struct page *page;
376         void *ptr;
377 
378         page = pfn_to_page(p >> PAGE_SHIFT);
379         if (PageUncached(page))
380                 ptr = (void *)p + __IA64_UNCACHED_OFFSET;
381         else
382                 ptr = __va(p);
383 
384         return ptr;
385 }
386 
387 /*
388  * Convert a virtual cached kernel memory pointer to an uncached pointer
389  */
390 static __inline__ void *
391 xlate_dev_kmem_ptr(void *p)
392 {
393         struct page *page;
394         void *ptr;
395 
396         page = virt_to_page((unsigned long)p);
397         if (PageUncached(page))
398                 ptr = (void *)__pa(p) + __IA64_UNCACHED_OFFSET;
399         else
400                 ptr = p;
401 
402         return ptr;
403 }
404 
405 #endif /* _ASM_IA64_UACCESS_H */
406 

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