xref: /openbmc/linux/arch/parisc/include/asm/uaccess.h (revision 12eb4683)
1 #ifndef __PARISC_UACCESS_H
2 #define __PARISC_UACCESS_H
3 
4 /*
5  * User space memory access functions
6  */
7 #include <asm/page.h>
8 #include <asm/cache.h>
9 #include <asm/errno.h>
10 #include <asm-generic/uaccess-unaligned.h>
11 
12 #define VERIFY_READ 0
13 #define VERIFY_WRITE 1
14 
15 #define KERNEL_DS	((mm_segment_t){0})
16 #define USER_DS 	((mm_segment_t){1})
17 
18 #define segment_eq(a,b)	((a).seg == (b).seg)
19 
20 #define get_ds()	(KERNEL_DS)
21 #define get_fs()	(current_thread_info()->addr_limit)
22 #define set_fs(x)	(current_thread_info()->addr_limit = (x))
23 
24 /*
25  * Note that since kernel addresses are in a separate address space on
26  * parisc, we don't need to do anything for access_ok().
27  * We just let the page fault handler do the right thing. This also means
28  * that put_user is the same as __put_user, etc.
29  */
30 
31 extern int __get_kernel_bad(void);
32 extern int __get_user_bad(void);
33 extern int __put_kernel_bad(void);
34 extern int __put_user_bad(void);
35 
36 static inline long access_ok(int type, const void __user * addr,
37 		unsigned long size)
38 {
39 	return 1;
40 }
41 
42 #define put_user __put_user
43 #define get_user __get_user
44 
45 #if !defined(CONFIG_64BIT)
46 #define LDD_KERNEL(ptr)		__get_kernel_bad();
47 #define LDD_USER(ptr)		__get_user_bad();
48 #define STD_KERNEL(x, ptr)	__put_kernel_asm64(x,ptr)
49 #define STD_USER(x, ptr)	__put_user_asm64(x,ptr)
50 #define ASM_WORD_INSN		".word\t"
51 #else
52 #define LDD_KERNEL(ptr)		__get_kernel_asm("ldd",ptr)
53 #define LDD_USER(ptr)		__get_user_asm("ldd",ptr)
54 #define STD_KERNEL(x, ptr)	__put_kernel_asm("std",x,ptr)
55 #define STD_USER(x, ptr)	__put_user_asm("std",x,ptr)
56 #define ASM_WORD_INSN		".dword\t"
57 #endif
58 
59 /*
60  * The exception table contains two values: the first is an address
61  * for an instruction that is allowed to fault, and the second is
62  * the address to the fixup routine. Even on a 64bit kernel we could
63  * use a 32bit (unsigned int) address here.
64  */
65 
66 struct exception_table_entry {
67 	unsigned long insn;	/* address of insn that is allowed to fault. */
68 	unsigned long fixup;	/* fixup routine */
69 };
70 
71 #define ASM_EXCEPTIONTABLE_ENTRY( fault_addr, except_addr )\
72 	".section __ex_table,\"aw\"\n"			   \
73 	ASM_WORD_INSN #fault_addr ", " #except_addr "\n\t" \
74 	".previous\n"
75 
76 /*
77  * The page fault handler stores, in a per-cpu area, the following information
78  * if a fixup routine is available.
79  */
80 struct exception_data {
81 	unsigned long fault_ip;
82 	unsigned long fault_space;
83 	unsigned long fault_addr;
84 };
85 
86 #define __get_user(x,ptr)                               \
87 ({                                                      \
88 	register long __gu_err __asm__ ("r8") = 0;      \
89 	register long __gu_val __asm__ ("r9") = 0;      \
90 							\
91 	if (segment_eq(get_fs(),KERNEL_DS)) {           \
92 	    switch (sizeof(*(ptr))) {                   \
93 	    case 1: __get_kernel_asm("ldb",ptr); break; \
94 	    case 2: __get_kernel_asm("ldh",ptr); break; \
95 	    case 4: __get_kernel_asm("ldw",ptr); break; \
96 	    case 8: LDD_KERNEL(ptr); break;		\
97 	    default: __get_kernel_bad(); break;         \
98 	    }                                           \
99 	}                                               \
100 	else {                                          \
101 	    switch (sizeof(*(ptr))) {                   \
102 	    case 1: __get_user_asm("ldb",ptr); break;   \
103 	    case 2: __get_user_asm("ldh",ptr); break;   \
104 	    case 4: __get_user_asm("ldw",ptr); break;   \
105 	    case 8: LDD_USER(ptr);  break;		\
106 	    default: __get_user_bad(); break;           \
107 	    }                                           \
108 	}                                               \
109 							\
110 	(x) = (__typeof__(*(ptr))) __gu_val;            \
111 	__gu_err;                                       \
112 })
113 
114 #define __get_kernel_asm(ldx,ptr)                       \
115 	__asm__("\n1:\t" ldx "\t0(%2),%0\n\t"		\
116 		ASM_EXCEPTIONTABLE_ENTRY(1b, fixup_get_user_skip_1)\
117 		: "=r"(__gu_val), "=r"(__gu_err)        \
118 		: "r"(ptr), "1"(__gu_err)		\
119 		: "r1");
120 
121 #define __get_user_asm(ldx,ptr)                         \
122 	__asm__("\n1:\t" ldx "\t0(%%sr3,%2),%0\n\t"	\
123 		ASM_EXCEPTIONTABLE_ENTRY(1b,fixup_get_user_skip_1)\
124 		: "=r"(__gu_val), "=r"(__gu_err)        \
125 		: "r"(ptr), "1"(__gu_err)		\
126 		: "r1");
127 
128 #define __put_user(x,ptr)                                       \
129 ({								\
130 	register long __pu_err __asm__ ("r8") = 0;      	\
131         __typeof__(*(ptr)) __x = (__typeof__(*(ptr)))(x);	\
132 								\
133 	if (segment_eq(get_fs(),KERNEL_DS)) {                   \
134 	    switch (sizeof(*(ptr))) {                           \
135 	    case 1: __put_kernel_asm("stb",__x,ptr); break;     \
136 	    case 2: __put_kernel_asm("sth",__x,ptr); break;     \
137 	    case 4: __put_kernel_asm("stw",__x,ptr); break;     \
138 	    case 8: STD_KERNEL(__x,ptr); break;			\
139 	    default: __put_kernel_bad(); break;			\
140 	    }                                                   \
141 	}                                                       \
142 	else {                                                  \
143 	    switch (sizeof(*(ptr))) {                           \
144 	    case 1: __put_user_asm("stb",__x,ptr); break;       \
145 	    case 2: __put_user_asm("sth",__x,ptr); break;       \
146 	    case 4: __put_user_asm("stw",__x,ptr); break;       \
147 	    case 8: STD_USER(__x,ptr); break;			\
148 	    default: __put_user_bad(); break;			\
149 	    }                                                   \
150 	}                                                       \
151 								\
152 	__pu_err;						\
153 })
154 
155 /*
156  * The "__put_user/kernel_asm()" macros tell gcc they read from memory
157  * instead of writing. This is because they do not write to any memory
158  * gcc knows about, so there are no aliasing issues. These macros must
159  * also be aware that "fixup_put_user_skip_[12]" are executed in the
160  * context of the fault, and any registers used there must be listed
161  * as clobbers. In this case only "r1" is used by the current routines.
162  * r8/r9 are already listed as err/val.
163  */
164 
165 #define __put_kernel_asm(stx,x,ptr)                         \
166 	__asm__ __volatile__ (                              \
167 		"\n1:\t" stx "\t%2,0(%1)\n\t"		    \
168 		ASM_EXCEPTIONTABLE_ENTRY(1b,fixup_put_user_skip_1)\
169 		: "=r"(__pu_err)                            \
170 		: "r"(ptr), "r"(x), "0"(__pu_err)	    \
171 	    	: "r1")
172 
173 #define __put_user_asm(stx,x,ptr)                           \
174 	__asm__ __volatile__ (                              \
175 		"\n1:\t" stx "\t%2,0(%%sr3,%1)\n\t"	    \
176 		ASM_EXCEPTIONTABLE_ENTRY(1b,fixup_put_user_skip_1)\
177 		: "=r"(__pu_err)                            \
178 		: "r"(ptr), "r"(x), "0"(__pu_err)	    \
179 		: "r1")
180 
181 
182 #if !defined(CONFIG_64BIT)
183 
184 #define __put_kernel_asm64(__val,ptr) do {		    \
185 	__asm__ __volatile__ (				    \
186 		"\n1:\tstw %2,0(%1)"			    \
187 		"\n2:\tstw %R2,4(%1)\n\t"		    \
188 		ASM_EXCEPTIONTABLE_ENTRY(1b,fixup_put_user_skip_2)\
189 		ASM_EXCEPTIONTABLE_ENTRY(2b,fixup_put_user_skip_1)\
190 		: "=r"(__pu_err)                            \
191 		: "r"(ptr), "r"(__val), "0"(__pu_err) \
192 		: "r1");				    \
193 } while (0)
194 
195 #define __put_user_asm64(__val,ptr) do {	    	    \
196 	__asm__ __volatile__ (				    \
197 		"\n1:\tstw %2,0(%%sr3,%1)"		    \
198 		"\n2:\tstw %R2,4(%%sr3,%1)\n\t"		    \
199 		ASM_EXCEPTIONTABLE_ENTRY(1b,fixup_put_user_skip_2)\
200 		ASM_EXCEPTIONTABLE_ENTRY(2b,fixup_put_user_skip_1)\
201 		: "=r"(__pu_err)                            \
202 		: "r"(ptr), "r"(__val), "0"(__pu_err) \
203 		: "r1");				    \
204 } while (0)
205 
206 #endif /* !defined(CONFIG_64BIT) */
207 
208 
209 /*
210  * Complex access routines -- external declarations
211  */
212 
213 extern unsigned long lcopy_to_user(void __user *, const void *, unsigned long);
214 extern unsigned long lcopy_from_user(void *, const void __user *, unsigned long);
215 extern unsigned long lcopy_in_user(void __user *, const void __user *, unsigned long);
216 extern long strncpy_from_user(char *, const char __user *, long);
217 extern unsigned lclear_user(void __user *,unsigned long);
218 extern long lstrnlen_user(const char __user *,long);
219 /*
220  * Complex access routines -- macros
221  */
222 #define user_addr_max() (~0UL)
223 
224 #define strnlen_user lstrnlen_user
225 #define strlen_user(str) lstrnlen_user(str, 0x7fffffffL)
226 #define clear_user lclear_user
227 #define __clear_user lclear_user
228 
229 unsigned long copy_to_user(void __user *dst, const void *src, unsigned long len);
230 #define __copy_to_user copy_to_user
231 unsigned long __copy_from_user(void *dst, const void __user *src, unsigned long len);
232 unsigned long copy_in_user(void __user *dst, const void __user *src, unsigned long len);
233 #define __copy_in_user copy_in_user
234 #define __copy_to_user_inatomic __copy_to_user
235 #define __copy_from_user_inatomic __copy_from_user
236 
237 extern void copy_from_user_overflow(void)
238 #ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
239         __compiletime_error("copy_from_user() buffer size is not provably correct")
240 #else
241         __compiletime_warning("copy_from_user() buffer size is not provably correct")
242 #endif
243 ;
244 
245 static inline unsigned long __must_check copy_from_user(void *to,
246                                           const void __user *from,
247                                           unsigned long n)
248 {
249         int sz = __compiletime_object_size(to);
250         int ret = -EFAULT;
251 
252         if (likely(sz == -1 || !__builtin_constant_p(n) || sz >= n))
253                 ret = __copy_from_user(to, from, n);
254         else
255                 copy_from_user_overflow();
256 
257         return ret;
258 }
259 
260 struct pt_regs;
261 int fixup_exception(struct pt_regs *regs);
262 
263 #endif /* __PARISC_UACCESS_H */
264