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Merge tag 'md-3.9-fixes' of git://neil.brown.name/md
[karo-tx-linux.git] / arch / s390 / lib / uaccess_mvcos.c
1 /*
2  *  Optimized user space space access functions based on mvcos.
3  *
4  *    Copyright IBM Corp. 2006
5  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
6  *               Gerald Schaefer (gerald.schaefer@de.ibm.com)
7  */
8
9 #include <linux/errno.h>
10 #include <linux/mm.h>
11 #include <asm/uaccess.h>
12 #include <asm/futex.h>
13 #include "uaccess.h"
14
15 #ifndef CONFIG_64BIT
16 #define AHI     "ahi"
17 #define ALR     "alr"
18 #define CLR     "clr"
19 #define LHI     "lhi"
20 #define SLR     "slr"
21 #else
22 #define AHI     "aghi"
23 #define ALR     "algr"
24 #define CLR     "clgr"
25 #define LHI     "lghi"
26 #define SLR     "slgr"
27 #endif
28
29 static size_t copy_from_user_mvcos(size_t size, const void __user *ptr, void *x)
30 {
31         register unsigned long reg0 asm("0") = 0x81UL;
32         unsigned long tmp1, tmp2;
33
34         tmp1 = -4096UL;
35         asm volatile(
36                 "0: .insn ss,0xc80000000000,0(%0,%2),0(%1),0\n"
37                 "9: jz    7f\n"
38                 "1:"ALR"  %0,%3\n"
39                 "  "SLR"  %1,%3\n"
40                 "  "SLR"  %2,%3\n"
41                 "   j     0b\n"
42                 "2: la    %4,4095(%1)\n"/* %4 = ptr + 4095 */
43                 "   nr    %4,%3\n"      /* %4 = (ptr + 4095) & -4096 */
44                 "  "SLR"  %4,%1\n"
45                 "  "CLR"  %0,%4\n"      /* copy crosses next page boundary? */
46                 "   jnh   4f\n"
47                 "3: .insn ss,0xc80000000000,0(%4,%2),0(%1),0\n"
48                 "10:"SLR"  %0,%4\n"
49                 "  "ALR"  %2,%4\n"
50                 "4:"LHI"  %4,-1\n"
51                 "  "ALR"  %4,%0\n"      /* copy remaining size, subtract 1 */
52                 "   bras  %3,6f\n"      /* memset loop */
53                 "   xc    0(1,%2),0(%2)\n"
54                 "5: xc    0(256,%2),0(%2)\n"
55                 "   la    %2,256(%2)\n"
56                 "6:"AHI"  %4,-256\n"
57                 "   jnm   5b\n"
58                 "   ex    %4,0(%3)\n"
59                 "   j     8f\n"
60                 "7:"SLR"  %0,%0\n"
61                 "8: \n"
62                 EX_TABLE(0b,2b) EX_TABLE(3b,4b) EX_TABLE(9b,2b) EX_TABLE(10b,4b)
63                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
64                 : "d" (reg0) : "cc", "memory");
65         return size;
66 }
67
68 static size_t copy_from_user_mvcos_check(size_t size, const void __user *ptr, void *x)
69 {
70         if (size <= 256)
71                 return copy_from_user_std(size, ptr, x);
72         return copy_from_user_mvcos(size, ptr, x);
73 }
74
75 static size_t copy_to_user_mvcos(size_t size, void __user *ptr, const void *x)
76 {
77         register unsigned long reg0 asm("0") = 0x810000UL;
78         unsigned long tmp1, tmp2;
79
80         tmp1 = -4096UL;
81         asm volatile(
82                 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
83                 "6: jz    4f\n"
84                 "1:"ALR"  %0,%3\n"
85                 "  "SLR"  %1,%3\n"
86                 "  "SLR"  %2,%3\n"
87                 "   j     0b\n"
88                 "2: la    %4,4095(%1)\n"/* %4 = ptr + 4095 */
89                 "   nr    %4,%3\n"      /* %4 = (ptr + 4095) & -4096 */
90                 "  "SLR"  %4,%1\n"
91                 "  "CLR"  %0,%4\n"      /* copy crosses next page boundary? */
92                 "   jnh   5f\n"
93                 "3: .insn ss,0xc80000000000,0(%4,%1),0(%2),0\n"
94                 "7:"SLR"  %0,%4\n"
95                 "   j     5f\n"
96                 "4:"SLR"  %0,%0\n"
97                 "5: \n"
98                 EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b)
99                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
100                 : "d" (reg0) : "cc", "memory");
101         return size;
102 }
103
104 static size_t copy_to_user_mvcos_check(size_t size, void __user *ptr,
105                                        const void *x)
106 {
107         if (size <= 256)
108                 return copy_to_user_std(size, ptr, x);
109         return copy_to_user_mvcos(size, ptr, x);
110 }
111
112 static size_t copy_in_user_mvcos(size_t size, void __user *to,
113                                  const void __user *from)
114 {
115         register unsigned long reg0 asm("0") = 0x810081UL;
116         unsigned long tmp1, tmp2;
117
118         tmp1 = -4096UL;
119         /* FIXME: copy with reduced length. */
120         asm volatile(
121                 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
122                 "   jz    2f\n"
123                 "1:"ALR"  %0,%3\n"
124                 "  "SLR"  %1,%3\n"
125                 "  "SLR"  %2,%3\n"
126                 "   j     0b\n"
127                 "2:"SLR"  %0,%0\n"
128                 "3: \n"
129                 EX_TABLE(0b,3b)
130                 : "+a" (size), "+a" (to), "+a" (from), "+a" (tmp1), "=a" (tmp2)
131                 : "d" (reg0) : "cc", "memory");
132         return size;
133 }
134
135 static size_t clear_user_mvcos(size_t size, void __user *to)
136 {
137         register unsigned long reg0 asm("0") = 0x810000UL;
138         unsigned long tmp1, tmp2;
139
140         tmp1 = -4096UL;
141         asm volatile(
142                 "0: .insn ss,0xc80000000000,0(%0,%1),0(%4),0\n"
143                 "   jz    4f\n"
144                 "1:"ALR"  %0,%2\n"
145                 "  "SLR"  %1,%2\n"
146                 "   j     0b\n"
147                 "2: la    %3,4095(%1)\n"/* %4 = to + 4095 */
148                 "   nr    %3,%2\n"      /* %4 = (to + 4095) & -4096 */
149                 "  "SLR"  %3,%1\n"
150                 "  "CLR"  %0,%3\n"      /* copy crosses next page boundary? */
151                 "   jnh   5f\n"
152                 "3: .insn ss,0xc80000000000,0(%3,%1),0(%4),0\n"
153                 "  "SLR"  %0,%3\n"
154                 "   j     5f\n"
155                 "4:"SLR"  %0,%0\n"
156                 "5: \n"
157                 EX_TABLE(0b,2b) EX_TABLE(3b,5b)
158                 : "+a" (size), "+a" (to), "+a" (tmp1), "=a" (tmp2)
159                 : "a" (empty_zero_page), "d" (reg0) : "cc", "memory");
160         return size;
161 }
162
163 static size_t strnlen_user_mvcos(size_t count, const char __user *src)
164 {
165         size_t done, len, offset, len_str;
166         char buf[256];
167
168         done = 0;
169         do {
170                 offset = (size_t)src & ~PAGE_MASK;
171                 len = min(256UL, PAGE_SIZE - offset);
172                 len = min(count - done, len);
173                 if (copy_from_user_mvcos(len, src, buf))
174                         return 0;
175                 len_str = strnlen(buf, len);
176                 done += len_str;
177                 src += len_str;
178         } while ((len_str == len) && (done < count));
179         return done + 1;
180 }
181
182 static size_t strncpy_from_user_mvcos(size_t count, const char __user *src,
183                                       char *dst)
184 {
185         size_t done, len, offset, len_str;
186
187         if (unlikely(!count))
188                 return 0;
189         done = 0;
190         do {
191                 offset = (size_t)src & ~PAGE_MASK;
192                 len = min(count - done, PAGE_SIZE - offset);
193                 if (copy_from_user_mvcos(len, src, dst))
194                         return -EFAULT;
195                 len_str = strnlen(dst, len);
196                 done += len_str;
197                 src += len_str;
198                 dst += len_str;
199         } while ((len_str == len) && (done < count));
200         return done;
201 }
202
203 struct uaccess_ops uaccess_mvcos = {
204         .copy_from_user = copy_from_user_mvcos_check,
205         .copy_from_user_small = copy_from_user_std,
206         .copy_to_user = copy_to_user_mvcos_check,
207         .copy_to_user_small = copy_to_user_std,
208         .copy_in_user = copy_in_user_mvcos,
209         .clear_user = clear_user_mvcos,
210         .strnlen_user = strnlen_user_std,
211         .strncpy_from_user = strncpy_from_user_std,
212         .futex_atomic_op = futex_atomic_op_std,
213         .futex_atomic_cmpxchg = futex_atomic_cmpxchg_std,
214 };
215
216 struct uaccess_ops uaccess_mvcos_switch = {
217         .copy_from_user = copy_from_user_mvcos,
218         .copy_from_user_small = copy_from_user_mvcos,
219         .copy_to_user = copy_to_user_mvcos,
220         .copy_to_user_small = copy_to_user_mvcos,
221         .copy_in_user = copy_in_user_mvcos,
222         .clear_user = clear_user_mvcos,
223         .strnlen_user = strnlen_user_mvcos,
224         .strncpy_from_user = strncpy_from_user_mvcos,
225         .futex_atomic_op = futex_atomic_op_pt,
226         .futex_atomic_cmpxchg = futex_atomic_cmpxchg_pt,
227 };