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1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_IA64_UACCESS_H
3 #define _ASM_IA64_UACCESS_H
6 * This file defines various macros to transfer memory areas across
7 * the user/kernel boundary. This needs to be done carefully because
8 * this code is executed in kernel mode and uses user-specified
9 * addresses. Thus, we need to be careful not to let the user to
10 * trick us into accessing kernel memory that would normally be
11 * inaccessible. This code is also fairly performance sensitive,
12 * so we want to spend as little time doing safety checks as
15 * To make matters a bit more interesting, these macros sometimes also
16 * called from within the kernel itself, in which case the address
17 * validity check must be skipped. The get_fs() macro tells us what
18 * to do: if get_fs()==USER_DS, checking is performed, if
19 * get_fs()==KERNEL_DS, checking is bypassed.
21 * Note that even if the memory area specified by the user is in a
22 * valid address range, it is still possible that we'll get a page
23 * fault while accessing it. This is handled by filling out an
24 * exception handler fixup entry for each instruction that has the
25 * potential to fault. When such a fault occurs, the page fault
26 * handler checks to see whether the faulting instruction has a fixup
27 * associated and, if so, sets r8 to -EFAULT and clears r9 to 0 and
28 * then resumes execution at the continuation point.
30 * Based on <asm-alpha/uaccess.h>.
32 * Copyright (C) 1998, 1999, 2001-2004 Hewlett-Packard Co
33 * David Mosberger-Tang <davidm@hpl.hp.com>
36 #include <linux/compiler.h>
37 #include <linux/page-flags.h>
39 #include <asm/intrinsics.h>
40 #include <linux/pgtable.h>
42 #include <asm/extable.h>
45 * For historical reasons, the following macros are grossly misnamed:
47 #define KERNEL_DS ((mm_segment_t) { ~0UL }) /* cf. access_ok() */
48 #define USER_DS ((mm_segment_t) { TASK_SIZE-1 }) /* cf. access_ok() */
50 #define get_fs() (current_thread_info()->addr_limit)
51 #define set_fs(x) (current_thread_info()->addr_limit = (x))
53 #define segment_eq(a, b) ((a).seg == (b).seg)
56 * When accessing user memory, we need to make sure the entire area really is in
57 * user-level space. In order to do this efficiently, we make sure that the page at
58 * address TASK_SIZE is never valid. We also need to make sure that the address doesn't
59 * point inside the virtually mapped linear page table.
61 static inline int __access_ok(const void __user
*p
, unsigned long size
)
63 unsigned long addr
= (unsigned long)p
;
64 unsigned long seg
= get_fs().seg
;
65 return likely(addr
<= seg
) &&
66 (seg
== KERNEL_DS
.seg
|| likely(REGION_OFFSET(addr
) < RGN_MAP_LIMIT
));
68 #define access_ok(addr, size) __access_ok((addr), (size))
71 * These are the main single-value transfer routines. They automatically
72 * use the right size if we just have the right pointer type.
75 * (a) re-use the arguments for side effects (sizeof/typeof is ok)
76 * (b) require any knowledge of processes at this stage
78 #define put_user(x, ptr) __put_user_check((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr)))
79 #define get_user(x, ptr) __get_user_check((x), (ptr), sizeof(*(ptr)))
82 * The "__xxx" versions do not do address space checking, useful when
83 * doing multiple accesses to the same area (the programmer has to do the
84 * checks by hand with "access_ok()")
86 #define __put_user(x, ptr) __put_user_nocheck((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr)))
87 #define __get_user(x, ptr) __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
90 struct __large_struct
{ unsigned long buf
[100]; };
91 # define __m(x) (*(struct __large_struct __user *)(x))
93 /* We need to declare the __ex_table section before we can use it in .xdata. */
94 asm (".section \"__ex_table\", \"a\"\n\t.previous");
96 # define __get_user_size(val, addr, n, err) \
98 register long __gu_r8 asm ("r8") = 0; \
99 register long __gu_r9 asm ("r9"); \
100 asm ("\n[1:]\tld"#n" %0=%2%P2\t// %0 and %1 get overwritten by exception handler\n" \
101 "\t.xdata4 \"__ex_table\", 1b-., 1f-.+4\n" \
103 : "=r"(__gu_r9), "=r"(__gu_r8) : "m"(__m(addr)), "1"(__gu_r8)); \
109 * The "__put_user_size()" macro tells gcc it reads from memory instead of writing it. This
110 * is because they do not write to any memory gcc knows about, so there are no aliasing
113 # define __put_user_size(val, addr, n, err) \
115 register long __pu_r8 asm ("r8") = 0; \
116 asm volatile ("\n[1:]\tst"#n" %1=%r2%P1\t// %0 gets overwritten by exception handler\n" \
117 "\t.xdata4 \"__ex_table\", 1b-., 1f-.\n" \
119 : "=r"(__pu_r8) : "m"(__m(addr)), "rO"(val), "0"(__pu_r8)); \
123 #else /* !ASM_SUPPORTED */
124 # define RELOC_TYPE 2 /* ip-rel */
125 # define __get_user_size(val, addr, n, err) \
127 __ld_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE); \
128 (err) = ia64_getreg(_IA64_REG_R8); \
129 (val) = ia64_getreg(_IA64_REG_R9); \
131 # define __put_user_size(val, addr, n, err) \
133 __st_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE, \
134 (__force unsigned long) (val)); \
135 (err) = ia64_getreg(_IA64_REG_R8); \
137 #endif /* !ASM_SUPPORTED */
139 extern void __get_user_unknown (void);
142 * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which
143 * could clobber r8 and r9 (among others). Thus, be careful not to evaluate it while
146 #define __do_get_user(check, x, ptr, size) \
148 const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
149 __typeof__ (size) __gu_size = (size); \
150 long __gu_err = -EFAULT; \
151 unsigned long __gu_val = 0; \
152 if (!check || __access_ok(__gu_ptr, size)) \
153 switch (__gu_size) { \
154 case 1: __get_user_size(__gu_val, __gu_ptr, 1, __gu_err); break; \
155 case 2: __get_user_size(__gu_val, __gu_ptr, 2, __gu_err); break; \
156 case 4: __get_user_size(__gu_val, __gu_ptr, 4, __gu_err); break; \
157 case 8: __get_user_size(__gu_val, __gu_ptr, 8, __gu_err); break; \
158 default: __get_user_unknown(); break; \
160 (x) = (__force __typeof__(*(__gu_ptr))) __gu_val; \
164 #define __get_user_nocheck(x, ptr, size) __do_get_user(0, x, ptr, size)
165 #define __get_user_check(x, ptr, size) __do_get_user(1, x, ptr, size)
167 extern void __put_user_unknown (void);
170 * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which
171 * could clobber r8 (among others). Thus, be careful not to evaluate them while using r8.
173 #define __do_put_user(check, x, ptr, size) \
175 __typeof__ (x) __pu_x = (x); \
176 __typeof__ (*(ptr)) __user *__pu_ptr = (ptr); \
177 __typeof__ (size) __pu_size = (size); \
178 long __pu_err = -EFAULT; \
180 if (!check || __access_ok(__pu_ptr, __pu_size)) \
181 switch (__pu_size) { \
182 case 1: __put_user_size(__pu_x, __pu_ptr, 1, __pu_err); break; \
183 case 2: __put_user_size(__pu_x, __pu_ptr, 2, __pu_err); break; \
184 case 4: __put_user_size(__pu_x, __pu_ptr, 4, __pu_err); break; \
185 case 8: __put_user_size(__pu_x, __pu_ptr, 8, __pu_err); break; \
186 default: __put_user_unknown(); break; \
191 #define __put_user_nocheck(x, ptr, size) __do_put_user(0, x, ptr, size)
192 #define __put_user_check(x, ptr, size) __do_put_user(1, x, ptr, size)
195 * Complex access routines
197 extern unsigned long __must_check
__copy_user (void __user
*to
, const void __user
*from
,
198 unsigned long count
);
200 static inline unsigned long
201 raw_copy_to_user(void __user
*to
, const void *from
, unsigned long count
)
203 return __copy_user(to
, (__force
void __user
*) from
, count
);
206 static inline unsigned long
207 raw_copy_from_user(void *to
, const void __user
*from
, unsigned long count
)
209 return __copy_user((__force
void __user
*) to
, from
, count
);
212 #define INLINE_COPY_FROM_USER
213 #define INLINE_COPY_TO_USER
215 extern unsigned long __do_clear_user (void __user
*, unsigned long);
217 #define __clear_user(to, n) __do_clear_user(to, n)
219 #define clear_user(to, n) \
221 unsigned long __cu_len = (n); \
222 if (__access_ok(to, __cu_len)) \
223 __cu_len = __do_clear_user(to, __cu_len); \
229 * Returns: -EFAULT if exception before terminator, N if the entire buffer filled, else
232 extern long __must_check
__strncpy_from_user (char *to
, const char __user
*from
, long to_len
);
234 #define strncpy_from_user(to, from, n) \
236 const char __user * __sfu_from = (from); \
237 long __sfu_ret = -EFAULT; \
238 if (__access_ok(__sfu_from, 0)) \
239 __sfu_ret = __strncpy_from_user((to), __sfu_from, (n)); \
244 * Returns: 0 if exception before NUL or reaching the supplied limit
245 * (N), a value greater than N if the limit would be exceeded, else
248 extern unsigned long __strnlen_user (const char __user
*, long);
250 #define strnlen_user(str, len) \
252 const char __user *__su_str = (str); \
253 unsigned long __su_ret = 0; \
254 if (__access_ok(__su_str, 0)) \
255 __su_ret = __strnlen_user(__su_str, len); \
259 #define ARCH_HAS_TRANSLATE_MEM_PTR 1
260 static __inline__
void *
261 xlate_dev_mem_ptr(phys_addr_t p
)
266 page
= pfn_to_page(p
>> PAGE_SHIFT
);
267 if (PageUncached(page
))
268 ptr
= (void *)p
+ __IA64_UNCACHED_OFFSET
;
276 * Convert a virtual cached kernel memory pointer to an uncached pointer
278 static __inline__
void *
279 xlate_dev_kmem_ptr(void *p
)
284 page
= virt_to_page((unsigned long)p
);
285 if (PageUncached(page
))
286 ptr
= (void *)__pa(p
) + __IA64_UNCACHED_OFFSET
;
293 #endif /* _ASM_IA64_UACCESS_H */