m68k: Kill several external declarations in source files
[linux-2.6.git] / arch / s390 / lib / uaccess_mvcos.c
1 /*
2  *  arch/s390/lib/uaccess_mvcos.c
3  *
4  *  Optimized user space space access functions based on mvcos.
5  *
6  *    Copyright (C) IBM Corp. 2006
7  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
8  *               Gerald Schaefer (gerald.schaefer@de.ibm.com)
9  */
10
11 #include <linux/errno.h>
12 #include <linux/mm.h>
13 #include <asm/uaccess.h>
14 #include <asm/futex.h>
15 #include "uaccess.h"
16
17 #ifndef __s390x__
18 #define AHI     "ahi"
19 #define ALR     "alr"
20 #define CLR     "clr"
21 #define LHI     "lhi"
22 #define SLR     "slr"
23 #else
24 #define AHI     "aghi"
25 #define ALR     "algr"
26 #define CLR     "clgr"
27 #define LHI     "lghi"
28 #define SLR     "slgr"
29 #endif
30
31 static size_t copy_from_user_mvcos(size_t size, const void __user *ptr, void *x)
32 {
33         register unsigned long reg0 asm("0") = 0x81UL;
34         unsigned long tmp1, tmp2;
35
36         tmp1 = -4096UL;
37         asm volatile(
38                 "0: .insn ss,0xc80000000000,0(%0,%2),0(%1),0\n"
39                 "   jz    7f\n"
40                 "1:"ALR"  %0,%3\n"
41                 "  "SLR"  %1,%3\n"
42                 "  "SLR"  %2,%3\n"
43                 "   j     0b\n"
44                 "2: la    %4,4095(%1)\n"/* %4 = ptr + 4095 */
45                 "   nr    %4,%3\n"      /* %4 = (ptr + 4095) & -4096 */
46                 "  "SLR"  %4,%1\n"
47                 "  "CLR"  %0,%4\n"      /* copy crosses next page boundary? */
48                 "   jnh   4f\n"
49                 "3: .insn ss,0xc80000000000,0(%4,%2),0(%1),0\n"
50                 "  "SLR"  %0,%4\n"
51                 "  "ALR"  %2,%4\n"
52                 "4:"LHI"  %4,-1\n"
53                 "  "ALR"  %4,%0\n"      /* copy remaining size, subtract 1 */
54                 "   bras  %3,6f\n"      /* memset loop */
55                 "   xc    0(1,%2),0(%2)\n"
56                 "5: xc    0(256,%2),0(%2)\n"
57                 "   la    %2,256(%2)\n"
58                 "6:"AHI"  %4,-256\n"
59                 "   jnm   5b\n"
60                 "   ex    %4,0(%3)\n"
61                 "   j     8f\n"
62                 "7:"SLR"  %0,%0\n"
63                 "8: \n"
64                 EX_TABLE(0b,2b) EX_TABLE(3b,4b)
65                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
66                 : "d" (reg0) : "cc", "memory");
67         return size;
68 }
69
70 static size_t copy_from_user_mvcos_check(size_t size, const void __user *ptr, void *x)
71 {
72         if (size <= 256)
73                 return copy_from_user_std(size, ptr, x);
74         return copy_from_user_mvcos(size, ptr, x);
75 }
76
77 static size_t copy_to_user_mvcos(size_t size, void __user *ptr, const void *x)
78 {
79         register unsigned long reg0 asm("0") = 0x810000UL;
80         unsigned long tmp1, tmp2;
81
82         tmp1 = -4096UL;
83         asm volatile(
84                 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
85                 "   jz    4f\n"
86                 "1:"ALR"  %0,%3\n"
87                 "  "SLR"  %1,%3\n"
88                 "  "SLR"  %2,%3\n"
89                 "   j     0b\n"
90                 "2: la    %4,4095(%1)\n"/* %4 = ptr + 4095 */
91                 "   nr    %4,%3\n"      /* %4 = (ptr + 4095) & -4096 */
92                 "  "SLR"  %4,%1\n"
93                 "  "CLR"  %0,%4\n"      /* copy crosses next page boundary? */
94                 "   jnh   5f\n"
95                 "3: .insn ss,0xc80000000000,0(%4,%1),0(%2),0\n"
96                 "  "SLR"  %0,%4\n"
97                 "   j     5f\n"
98                 "4:"SLR"  %0,%0\n"
99                 "5: \n"
100                 EX_TABLE(0b,2b) EX_TABLE(3b,5b)
101                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
102                 : "d" (reg0) : "cc", "memory");
103         return size;
104 }
105
106 static size_t copy_to_user_mvcos_check(size_t size, void __user *ptr,
107                                        const void *x)
108 {
109         if (size <= 256)
110                 return copy_to_user_std(size, ptr, x);
111         return copy_to_user_mvcos(size, ptr, x);
112 }
113
114 static size_t copy_in_user_mvcos(size_t size, void __user *to,
115                                  const void __user *from)
116 {
117         register unsigned long reg0 asm("0") = 0x810081UL;
118         unsigned long tmp1, tmp2;
119
120         tmp1 = -4096UL;
121         /* FIXME: copy with reduced length. */
122         asm volatile(
123                 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
124                 "   jz    2f\n"
125                 "1:"ALR"  %0,%3\n"
126                 "  "SLR"  %1,%3\n"
127                 "  "SLR"  %2,%3\n"
128                 "   j     0b\n"
129                 "2:"SLR"  %0,%0\n"
130                 "3: \n"
131                 EX_TABLE(0b,3b)
132                 : "+a" (size), "+a" (to), "+a" (from), "+a" (tmp1), "=a" (tmp2)
133                 : "d" (reg0) : "cc", "memory");
134         return size;
135 }
136
137 static size_t clear_user_mvcos(size_t size, void __user *to)
138 {
139         register unsigned long reg0 asm("0") = 0x810000UL;
140         unsigned long tmp1, tmp2;
141
142         tmp1 = -4096UL;
143         asm volatile(
144                 "0: .insn ss,0xc80000000000,0(%0,%1),0(%4),0\n"
145                 "   jz    4f\n"
146                 "1:"ALR"  %0,%2\n"
147                 "  "SLR"  %1,%2\n"
148                 "   j     0b\n"
149                 "2: la    %3,4095(%1)\n"/* %4 = to + 4095 */
150                 "   nr    %3,%2\n"      /* %4 = (to + 4095) & -4096 */
151                 "  "SLR"  %3,%1\n"
152                 "  "CLR"  %0,%3\n"      /* copy crosses next page boundary? */
153                 "   jnh   5f\n"
154                 "3: .insn ss,0xc80000000000,0(%3,%1),0(%4),0\n"
155                 "  "SLR"  %0,%3\n"
156                 "   j     5f\n"
157                 "4:"SLR"  %0,%0\n"
158                 "5: \n"
159                 EX_TABLE(0b,2b) EX_TABLE(3b,5b)
160                 : "+a" (size), "+a" (to), "+a" (tmp1), "=a" (tmp2)
161                 : "a" (empty_zero_page), "d" (reg0) : "cc", "memory");
162         return size;
163 }
164
165 #ifdef CONFIG_S390_SWITCH_AMODE
166 static size_t strnlen_user_mvcos(size_t count, const char __user *src)
167 {
168         char buf[256];
169         int rc;
170         size_t done, len, len_str;
171
172         done = 0;
173         do {
174                 len = min(count - done, (size_t) 256);
175                 rc = uaccess.copy_from_user(len, src + done, buf);
176                 if (unlikely(rc == len))
177                         return 0;
178                 len -= rc;
179                 len_str = strnlen(buf, len);
180                 done += len_str;
181         } while ((len_str == len) && (done < count));
182         return done + 1;
183 }
184
185 static size_t strncpy_from_user_mvcos(size_t count, const char __user *src,
186                                       char *dst)
187 {
188         int rc;
189         size_t done, len, len_str;
190
191         done = 0;
192         do {
193                 len = min(count - done, (size_t) 4096);
194                 rc = uaccess.copy_from_user(len, src + done, dst);
195                 if (unlikely(rc == len))
196                         return -EFAULT;
197                 len -= rc;
198                 len_str = strnlen(dst, len);
199                 done += len_str;
200         } while ((len_str == len) && (done < count));
201         return done;
202 }
203 #endif /* CONFIG_S390_SWITCH_AMODE */
204
205 struct uaccess_ops uaccess_mvcos = {
206         .copy_from_user = copy_from_user_mvcos_check,
207         .copy_from_user_small = copy_from_user_std,
208         .copy_to_user = copy_to_user_mvcos_check,
209         .copy_to_user_small = copy_to_user_std,
210         .copy_in_user = copy_in_user_mvcos,
211         .clear_user = clear_user_mvcos,
212         .strnlen_user = strnlen_user_std,
213         .strncpy_from_user = strncpy_from_user_std,
214         .futex_atomic_op = futex_atomic_op_std,
215         .futex_atomic_cmpxchg = futex_atomic_cmpxchg_std,
216 };
217
218 #ifdef CONFIG_S390_SWITCH_AMODE
219 struct uaccess_ops uaccess_mvcos_switch = {
220         .copy_from_user = copy_from_user_mvcos,
221         .copy_from_user_small = copy_from_user_mvcos,
222         .copy_to_user = copy_to_user_mvcos,
223         .copy_to_user_small = copy_to_user_mvcos,
224         .copy_in_user = copy_in_user_mvcos,
225         .clear_user = clear_user_mvcos,
226         .strnlen_user = strnlen_user_mvcos,
227         .strncpy_from_user = strncpy_from_user_mvcos,
228         .futex_atomic_op = futex_atomic_op_pt,
229         .futex_atomic_cmpxchg = futex_atomic_cmpxchg_pt,
230 };
231 #endif