1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Standard user space access functions based on mvcp/mvcs and doing
4 * interesting things in the secondary space mode.
5 *
6 * Copyright IBM Corp. 2006,2014
7 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
8 * Gerald Schaefer (gerald.schaefer@de.ibm.com)
9 */
10
11 #include <linux/jump_label.h>
12 #include <linux/uaccess.h>
13 #include <linux/export.h>
14 #include <linux/errno.h>
15 #include <linux/mm.h>
16 #include <asm/mmu_context.h>
17 #include <asm/facility.h>
18
19 #ifdef CONFIG_DEBUG_ENTRY
debug_user_asce(int exit)20 void debug_user_asce(int exit)
21 {
22 unsigned long cr1, cr7;
23
24 __ctl_store(cr1, 1, 1);
25 __ctl_store(cr7, 7, 7);
26 if (cr1 == S390_lowcore.kernel_asce && cr7 == S390_lowcore.user_asce)
27 return;
28 panic("incorrect ASCE on kernel %s\n"
29 "cr1: %016lx cr7: %016lx\n"
30 "kernel: %016llx user: %016llx\n",
31 exit ? "exit" : "entry", cr1, cr7,
32 S390_lowcore.kernel_asce, S390_lowcore.user_asce);
33
34 }
35 #endif /*CONFIG_DEBUG_ENTRY */
36
37 #ifndef CONFIG_HAVE_MARCH_Z10_FEATURES
38 static DEFINE_STATIC_KEY_FALSE(have_mvcos);
39
uaccess_init(void)40 static int __init uaccess_init(void)
41 {
42 if (test_facility(27))
43 static_branch_enable(&have_mvcos);
44 return 0;
45 }
46 early_initcall(uaccess_init);
47
copy_with_mvcos(void)48 static inline int copy_with_mvcos(void)
49 {
50 if (static_branch_likely(&have_mvcos))
51 return 1;
52 return 0;
53 }
54 #else
copy_with_mvcos(void)55 static inline int copy_with_mvcos(void)
56 {
57 return 1;
58 }
59 #endif
60
copy_from_user_mvcos(void * x,const void __user * ptr,unsigned long size)61 static inline unsigned long copy_from_user_mvcos(void *x, const void __user *ptr,
62 unsigned long size)
63 {
64 unsigned long tmp1, tmp2;
65
66 tmp1 = -4096UL;
67 asm volatile(
68 " lghi 0,%[spec]\n"
69 "0: .insn ss,0xc80000000000,0(%0,%2),0(%1),0\n"
70 "6: jz 4f\n"
71 "1: algr %0,%3\n"
72 " slgr %1,%3\n"
73 " slgr %2,%3\n"
74 " j 0b\n"
75 "2: la %4,4095(%1)\n"/* %4 = ptr + 4095 */
76 " nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */
77 " slgr %4,%1\n"
78 " clgr %0,%4\n" /* copy crosses next page boundary? */
79 " jnh 5f\n"
80 "3: .insn ss,0xc80000000000,0(%4,%2),0(%1),0\n"
81 "7: slgr %0,%4\n"
82 " j 5f\n"
83 "4: slgr %0,%0\n"
84 "5:\n"
85 EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b)
86 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
87 : [spec] "K" (0x81UL)
88 : "cc", "memory", "0");
89 return size;
90 }
91
copy_from_user_mvcp(void * x,const void __user * ptr,unsigned long size)92 static inline unsigned long copy_from_user_mvcp(void *x, const void __user *ptr,
93 unsigned long size)
94 {
95 unsigned long tmp1, tmp2;
96
97 tmp1 = -256UL;
98 asm volatile(
99 " sacf 0\n"
100 "0: mvcp 0(%0,%2),0(%1),%3\n"
101 "7: jz 5f\n"
102 "1: algr %0,%3\n"
103 " la %1,256(%1)\n"
104 " la %2,256(%2)\n"
105 "2: mvcp 0(%0,%2),0(%1),%3\n"
106 "8: jnz 1b\n"
107 " j 5f\n"
108 "3: la %4,255(%1)\n" /* %4 = ptr + 255 */
109 " lghi %3,-4096\n"
110 " nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */
111 " slgr %4,%1\n"
112 " clgr %0,%4\n" /* copy crosses next page boundary? */
113 " jnh 6f\n"
114 "4: mvcp 0(%4,%2),0(%1),%3\n"
115 "9: slgr %0,%4\n"
116 " j 6f\n"
117 "5: slgr %0,%0\n"
118 "6: sacf 768\n"
119 EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b)
120 EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b)
121 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
122 : : "cc", "memory");
123 return size;
124 }
125
raw_copy_from_user(void * to,const void __user * from,unsigned long n)126 unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n)
127 {
128 if (copy_with_mvcos())
129 return copy_from_user_mvcos(to, from, n);
130 return copy_from_user_mvcp(to, from, n);
131 }
132 EXPORT_SYMBOL(raw_copy_from_user);
133
copy_to_user_mvcos(void __user * ptr,const void * x,unsigned long size)134 static inline unsigned long copy_to_user_mvcos(void __user *ptr, const void *x,
135 unsigned long size)
136 {
137 unsigned long tmp1, tmp2;
138
139 tmp1 = -4096UL;
140 asm volatile(
141 " llilh 0,%[spec]\n"
142 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
143 "6: jz 4f\n"
144 "1: algr %0,%3\n"
145 " slgr %1,%3\n"
146 " slgr %2,%3\n"
147 " j 0b\n"
148 "2: la %4,4095(%1)\n"/* %4 = ptr + 4095 */
149 " nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */
150 " slgr %4,%1\n"
151 " clgr %0,%4\n" /* copy crosses next page boundary? */
152 " jnh 5f\n"
153 "3: .insn ss,0xc80000000000,0(%4,%1),0(%2),0\n"
154 "7: slgr %0,%4\n"
155 " j 5f\n"
156 "4: slgr %0,%0\n"
157 "5:\n"
158 EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b)
159 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
160 : [spec] "K" (0x81UL)
161 : "cc", "memory", "0");
162 return size;
163 }
164
copy_to_user_mvcs(void __user * ptr,const void * x,unsigned long size)165 static inline unsigned long copy_to_user_mvcs(void __user *ptr, const void *x,
166 unsigned long size)
167 {
168 unsigned long tmp1, tmp2;
169
170 tmp1 = -256UL;
171 asm volatile(
172 " sacf 0\n"
173 "0: mvcs 0(%0,%1),0(%2),%3\n"
174 "7: jz 5f\n"
175 "1: algr %0,%3\n"
176 " la %1,256(%1)\n"
177 " la %2,256(%2)\n"
178 "2: mvcs 0(%0,%1),0(%2),%3\n"
179 "8: jnz 1b\n"
180 " j 5f\n"
181 "3: la %4,255(%1)\n" /* %4 = ptr + 255 */
182 " lghi %3,-4096\n"
183 " nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */
184 " slgr %4,%1\n"
185 " clgr %0,%4\n" /* copy crosses next page boundary? */
186 " jnh 6f\n"
187 "4: mvcs 0(%4,%1),0(%2),%3\n"
188 "9: slgr %0,%4\n"
189 " j 6f\n"
190 "5: slgr %0,%0\n"
191 "6: sacf 768\n"
192 EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b)
193 EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b)
194 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
195 : : "cc", "memory");
196 return size;
197 }
198
raw_copy_to_user(void __user * to,const void * from,unsigned long n)199 unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n)
200 {
201 if (copy_with_mvcos())
202 return copy_to_user_mvcos(to, from, n);
203 return copy_to_user_mvcs(to, from, n);
204 }
205 EXPORT_SYMBOL(raw_copy_to_user);
206
clear_user_mvcos(void __user * to,unsigned long size)207 static inline unsigned long clear_user_mvcos(void __user *to, unsigned long size)
208 {
209 unsigned long tmp1, tmp2;
210
211 tmp1 = -4096UL;
212 asm volatile(
213 " llilh 0,%[spec]\n"
214 "0: .insn ss,0xc80000000000,0(%0,%1),0(%4),0\n"
215 " jz 4f\n"
216 "1: algr %0,%2\n"
217 " slgr %1,%2\n"
218 " j 0b\n"
219 "2: la %3,4095(%1)\n"/* %4 = to + 4095 */
220 " nr %3,%2\n" /* %4 = (to + 4095) & -4096 */
221 " slgr %3,%1\n"
222 " clgr %0,%3\n" /* copy crosses next page boundary? */
223 " jnh 5f\n"
224 "3: .insn ss,0xc80000000000,0(%3,%1),0(%4),0\n"
225 " slgr %0,%3\n"
226 " j 5f\n"
227 "4: slgr %0,%0\n"
228 "5:\n"
229 EX_TABLE(0b,2b) EX_TABLE(3b,5b)
230 : "+a" (size), "+a" (to), "+a" (tmp1), "=a" (tmp2)
231 : "a" (empty_zero_page), [spec] "K" (0x81UL)
232 : "cc", "memory", "0");
233 return size;
234 }
235
clear_user_xc(void __user * to,unsigned long size)236 static inline unsigned long clear_user_xc(void __user *to, unsigned long size)
237 {
238 unsigned long tmp1, tmp2;
239
240 asm volatile(
241 " sacf 256\n"
242 " aghi %0,-1\n"
243 " jo 5f\n"
244 " bras %3,3f\n"
245 " xc 0(1,%1),0(%1)\n"
246 "0: aghi %0,257\n"
247 " la %2,255(%1)\n" /* %2 = ptr + 255 */
248 " srl %2,12\n"
249 " sll %2,12\n" /* %2 = (ptr + 255) & -4096 */
250 " slgr %2,%1\n"
251 " clgr %0,%2\n" /* clear crosses next page boundary? */
252 " jnh 5f\n"
253 " aghi %2,-1\n"
254 "1: ex %2,0(%3)\n"
255 " aghi %2,1\n"
256 " slgr %0,%2\n"
257 " j 5f\n"
258 "2: xc 0(256,%1),0(%1)\n"
259 " la %1,256(%1)\n"
260 "3: aghi %0,-256\n"
261 " jnm 2b\n"
262 "4: ex %0,0(%3)\n"
263 "5: slgr %0,%0\n"
264 "6: sacf 768\n"
265 EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
266 : "+a" (size), "+a" (to), "=a" (tmp1), "=a" (tmp2)
267 : : "cc", "memory");
268 return size;
269 }
270
__clear_user(void __user * to,unsigned long size)271 unsigned long __clear_user(void __user *to, unsigned long size)
272 {
273 if (copy_with_mvcos())
274 return clear_user_mvcos(to, size);
275 return clear_user_xc(to, size);
276 }
277 EXPORT_SYMBOL(__clear_user);
278
