1 #ifndef _ASM_IA64_UACCESS_H
2 #define _ASM_IA64_UACCESS_H
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
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.
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.
29 * Based on <asm-alpha/uaccess.h>.
31 * Copyright (C) 1998, 1999, 2001-2004 Hewlett-Packard Co
32 * David Mosberger-Tang <davidm@hpl.hp.com>
35 #include <linux/compiler.h>
36 #include <linux/errno.h>
37 #include <linux/sched.h>
39 #include <asm/intrinsics.h>
40 #include <asm/pgtable.h>
43 * For historical reasons, the following macros are grossly misnamed:
45 #define KERNEL_DS ((mm_segment_t) { ~0UL }) /* cf. access_ok() */
46 #define USER_DS ((mm_segment_t) { TASK_SIZE-1 }) /* cf. access_ok() */
49 #define VERIFY_WRITE 1
51 #define get_ds() (KERNEL_DS)
52 #define get_fs() (current_thread_info()->addr_limit)
53 #define set_fs(x) (current_thread_info()->addr_limit = (x))
55 #define segment_eq(a, b) ((a).seg == (b).seg)
58 * When accessing user memory, we need to make sure the entire area really is in
59 * user-level space. In order to do this efficiently, we make sure that the page at
60 * address TASK_SIZE is never valid. We also need to make sure that the address doesn't
61 * point inside the virtually mapped linear page table.
63 #define __access_ok(addr, size, segment) \
64 (likely((unsigned long) (addr) <= (segment).seg) \
65 && ((segment).seg == KERNEL_DS.seg \
66 || likely(REGION_OFFSET((unsigned long) (addr)) < RGN_MAP_LIMIT)))
67 #define access_ok(type, addr, size) __access_ok((addr), (size), get_fs())
70 verify_area (int type, const void *addr, unsigned long size)
72 return access_ok(type, addr, size) ? 0 : -EFAULT;
76 * These are the main single-value transfer routines. They automatically
77 * use the right size if we just have the right pointer type.
80 * (a) re-use the arguments for side effects (sizeof/typeof is ok)
81 * (b) require any knowledge of processes at this stage
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())
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()")
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)))
95 struct __large_struct { unsigned long buf[100]; };
96 # define __m(x) (*(struct __large_struct *)(x))
98 /* We need to declare the __ex_table section before we can use it in .xdata. */
99 asm (".section \"__ex_table\", \"a\"\n\t.previous");
101 # define __get_user_size(val, addr, n, err) \
103 register long __gu_r8 asm ("r8") = 0; \
104 register long __gu_r9 asm ("r9"); \
105 asm ("\n[1:]\tld"#n" %0=%2%P2\t// %0 and %1 get overwritten by exception handler\n" \
106 "\t.xdata4 \"__ex_table\", 1b-., 1f-.+4\n" \
108 : "=r"(__gu_r9), "=r"(__gu_r8) : "m"(__m(addr)), "1"(__gu_r8)); \
114 * The "__put_user_size()" macro tells gcc it reads from memory instead of writing it. This
115 * is because they do not write to any memory gcc knows about, so there are no aliasing
118 # define __put_user_size(val, addr, n, err) \
120 register long __pu_r8 asm ("r8") = 0; \
121 asm volatile ("\n[1:]\tst"#n" %1=%r2%P1\t// %0 gets overwritten by exception handler\n" \
122 "\t.xdata4 \"__ex_table\", 1b-., 1f-.\n" \
124 : "=r"(__pu_r8) : "m"(__m(addr)), "rO"(val), "0"(__pu_r8)); \
128 #else /* !ASM_SUPPORTED */
129 # define RELOC_TYPE 2 /* ip-rel */
130 # define __get_user_size(val, addr, n, err) \
132 __ld_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE); \
133 (err) = ia64_getreg(_IA64_REG_R8); \
134 (val) = ia64_getreg(_IA64_REG_R9); \
136 # define __put_user_size(val, addr, n, err) \
138 __st_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE, (unsigned long) (val)); \
139 (err) = ia64_getreg(_IA64_REG_R8); \
141 #endif /* !ASM_SUPPORTED */
143 extern void __get_user_unknown (void);
146 * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which
147 * could clobber r8 and r9 (among others). Thus, be careful not to evaluate it while
150 #define __do_get_user(check, x, ptr, size, segment) \
152 const __typeof__(*(ptr)) *__gu_ptr = (ptr); \
153 __typeof__ (size) __gu_size = (size); \
154 long __gu_err = -EFAULT, __gu_val = 0; \
156 if (!check || __access_ok((long) __gu_ptr, size, segment)) \
157 switch (__gu_size) { \
158 case 1: __get_user_size(__gu_val, __gu_ptr, 1, __gu_err); break; \
159 case 2: __get_user_size(__gu_val, __gu_ptr, 2, __gu_err); break; \
160 case 4: __get_user_size(__gu_val, __gu_ptr, 4, __gu_err); break; \
161 case 8: __get_user_size(__gu_val, __gu_ptr, 8, __gu_err); break; \
162 default: __get_user_unknown(); break; \
164 (x) = (__typeof__(*(__gu_ptr))) __gu_val; \
168 #define __get_user_nocheck(x, ptr, size) __do_get_user(0, x, ptr, size, KERNEL_DS)
169 #define __get_user_check(x, ptr, size, segment) __do_get_user(1, x, ptr, size, segment)
171 extern void __put_user_unknown (void);
174 * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which
175 * could clobber r8 (among others). Thus, be careful not to evaluate them while using r8.
177 #define __do_put_user(check, x, ptr, size, segment) \
179 __typeof__ (x) __pu_x = (x); \
180 __typeof__ (*(ptr)) *__pu_ptr = (ptr); \
181 __typeof__ (size) __pu_size = (size); \
182 long __pu_err = -EFAULT; \
184 if (!check || __access_ok((long) __pu_ptr, __pu_size, segment)) \
185 switch (__pu_size) { \
186 case 1: __put_user_size(__pu_x, __pu_ptr, 1, __pu_err); break; \
187 case 2: __put_user_size(__pu_x, __pu_ptr, 2, __pu_err); break; \
188 case 4: __put_user_size(__pu_x, __pu_ptr, 4, __pu_err); break; \
189 case 8: __put_user_size(__pu_x, __pu_ptr, 8, __pu_err); break; \
190 default: __put_user_unknown(); break; \
195 #define __put_user_nocheck(x, ptr, size) __do_put_user(0, x, ptr, size, KERNEL_DS)
196 #define __put_user_check(x, ptr, size, segment) __do_put_user(1, x, ptr, size, segment)
199 * Complex access routines
201 extern unsigned long __copy_user (void *to, const void *from, unsigned long count);
203 #define __copy_to_user(to, from, n) __copy_user((to), (from), (n))
204 #define __copy_from_user(to, from, n) __copy_user((to), (from), (n))
206 #define copy_to_user(to, from, n) __copy_tofrom_user((to), (from), (n), 1)
207 #define copy_from_user(to, from, n) __copy_tofrom_user((to), (from), (n), 0)
209 #define __copy_tofrom_user(to, from, n, check_to) \
211 void *__cu_to = (to); \
212 const void *__cu_from = (from); \
213 long __cu_len = (n); \
215 if (__access_ok((long) ((check_to) ? __cu_to : __cu_from), __cu_len, get_fs())) \
216 __cu_len = __copy_user(__cu_to, __cu_from, __cu_len); \
220 #define __copy_in_user(to, from, size) __copy_user((to), (from), (size))
222 static inline unsigned long
223 copy_in_user (void *to, const void *from, unsigned long n)
225 if (likely(access_ok(VERIFY_READ, from, n) && access_ok(VERIFY_WRITE, to, n)))
226 n = __copy_user(to, from, n);
230 extern unsigned long __do_clear_user (void *, unsigned long);
232 #define __clear_user(to, n) __do_clear_user(to, n)
234 #define clear_user(to, n) \
236 unsigned long __cu_len = (n); \
237 if (__access_ok((long) to, __cu_len, get_fs())) \
238 __cu_len = __do_clear_user(to, __cu_len); \
244 * Returns: -EFAULT if exception before terminator, N if the entire buffer filled, else
247 extern long __strncpy_from_user (char *to, const char *from, long to_len);
249 #define strncpy_from_user(to, from, n) \
251 const char * __sfu_from = (from); \
252 long __sfu_ret = -EFAULT; \
253 if (__access_ok((long) __sfu_from, 0, get_fs())) \
254 __sfu_ret = __strncpy_from_user((to), __sfu_from, (n)); \
258 /* Returns: 0 if bad, string length+1 (memory size) of string if ok */
259 extern unsigned long __strlen_user (const char *);
261 #define strlen_user(str) \
263 const char *__su_str = (str); \
264 unsigned long __su_ret = 0; \
265 if (__access_ok((long) __su_str, 0, get_fs())) \
266 __su_ret = __strlen_user(__su_str); \
271 * Returns: 0 if exception before NUL or reaching the supplied limit
272 * (N), a value greater than N if the limit would be exceeded, else
275 extern unsigned long __strnlen_user (const char *, long);
277 #define strnlen_user(str, len) \
279 const char *__su_str = (str); \
280 unsigned long __su_ret = 0; \
281 if (__access_ok((long) __su_str, 0, get_fs())) \
282 __su_ret = __strnlen_user(__su_str, len); \
286 /* Generic code can't deal with the location-relative format that we use for compactness. */
287 #define ARCH_HAS_SORT_EXTABLE
288 #define ARCH_HAS_SEARCH_EXTABLE
290 struct exception_table_entry {
291 int addr; /* location-relative address of insn this fixup is for */
292 int cont; /* location-relative continuation addr.; if bit 2 is set, r9 is set to 0 */
295 extern void ia64_handle_exception (struct pt_regs *regs, const struct exception_table_entry *e);
296 extern const struct exception_table_entry *search_exception_tables (unsigned long addr);
299 ia64_done_with_exception (struct pt_regs *regs)
301 const struct exception_table_entry *e;
302 e = search_exception_tables(regs->cr_iip + ia64_psr(regs)->ri);
304 ia64_handle_exception(regs, e);
310 #endif /* _ASM_IA64_UACCESS_H */