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/uaccess.h>
12 #include <linux/export.h>
13 #include <linux/mm.h>
14 #include <asm/asm-extable.h>
15
16 #ifdef CONFIG_DEBUG_ENTRY
debug_user_asce(int exit)17 void debug_user_asce(int exit)
18 {
19 unsigned long cr1, cr7;
20
21 __ctl_store(cr1, 1, 1);
22 __ctl_store(cr7, 7, 7);
23 if (cr1 == S390_lowcore.kernel_asce && cr7 == S390_lowcore.user_asce)
24 return;
25 panic("incorrect ASCE on kernel %s\n"
26 "cr1: %016lx cr7: %016lx\n"
27 "kernel: %016llx user: %016llx\n",
28 exit ? "exit" : "entry", cr1, cr7,
29 S390_lowcore.kernel_asce, S390_lowcore.user_asce);
30 }
31 #endif /*CONFIG_DEBUG_ENTRY */
32
raw_copy_from_user_key(void * to,const void __user * from,unsigned long size,unsigned long key)33 static unsigned long raw_copy_from_user_key(void *to, const void __user *from,
34 unsigned long size, unsigned long key)
35 {
36 unsigned long rem;
37 union oac spec = {
38 .oac2.key = key,
39 .oac2.as = PSW_BITS_AS_SECONDARY,
40 .oac2.k = 1,
41 .oac2.a = 1,
42 };
43
44 asm volatile(
45 " lr 0,%[spec]\n"
46 "0: mvcos 0(%[to]),0(%[from]),%[size]\n"
47 "1: jz 5f\n"
48 " algr %[size],%[val]\n"
49 " slgr %[from],%[val]\n"
50 " slgr %[to],%[val]\n"
51 " j 0b\n"
52 "2: la %[rem],4095(%[from])\n" /* rem = from + 4095 */
53 " nr %[rem],%[val]\n" /* rem = (from + 4095) & -4096 */
54 " slgr %[rem],%[from]\n"
55 " clgr %[size],%[rem]\n" /* copy crosses next page boundary? */
56 " jnh 6f\n"
57 "3: mvcos 0(%[to]),0(%[from]),%[rem]\n"
58 "4: slgr %[size],%[rem]\n"
59 " j 6f\n"
60 "5: slgr %[size],%[size]\n"
61 "6:\n"
62 EX_TABLE(0b, 2b)
63 EX_TABLE(1b, 2b)
64 EX_TABLE(3b, 6b)
65 EX_TABLE(4b, 6b)
66 : [size] "+&a" (size), [from] "+&a" (from), [to] "+&a" (to), [rem] "=&a" (rem)
67 : [val] "a" (-4096UL), [spec] "d" (spec.val)
68 : "cc", "memory", "0");
69 return size;
70 }
71
raw_copy_from_user(void * to,const void __user * from,unsigned long n)72 unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n)
73 {
74 return raw_copy_from_user_key(to, from, n, 0);
75 }
76 EXPORT_SYMBOL(raw_copy_from_user);
77
_copy_from_user_key(void * to,const void __user * from,unsigned long n,unsigned long key)78 unsigned long _copy_from_user_key(void *to, const void __user *from,
79 unsigned long n, unsigned long key)
80 {
81 unsigned long res = n;
82
83 might_fault();
84 if (!should_fail_usercopy()) {
85 instrument_copy_from_user_before(to, from, n);
86 res = raw_copy_from_user_key(to, from, n, key);
87 instrument_copy_from_user_after(to, from, n, res);
88 }
89 if (unlikely(res))
90 memset(to + (n - res), 0, res);
91 return res;
92 }
93 EXPORT_SYMBOL(_copy_from_user_key);
94
raw_copy_to_user_key(void __user * to,const void * from,unsigned long size,unsigned long key)95 static unsigned long raw_copy_to_user_key(void __user *to, const void *from,
96 unsigned long size, unsigned long key)
97 {
98 unsigned long rem;
99 union oac spec = {
100 .oac1.key = key,
101 .oac1.as = PSW_BITS_AS_SECONDARY,
102 .oac1.k = 1,
103 .oac1.a = 1,
104 };
105
106 asm volatile(
107 " lr 0,%[spec]\n"
108 "0: mvcos 0(%[to]),0(%[from]),%[size]\n"
109 "1: jz 5f\n"
110 " algr %[size],%[val]\n"
111 " slgr %[to],%[val]\n"
112 " slgr %[from],%[val]\n"
113 " j 0b\n"
114 "2: la %[rem],4095(%[to])\n" /* rem = to + 4095 */
115 " nr %[rem],%[val]\n" /* rem = (to + 4095) & -4096 */
116 " slgr %[rem],%[to]\n"
117 " clgr %[size],%[rem]\n" /* copy crosses next page boundary? */
118 " jnh 6f\n"
119 "3: mvcos 0(%[to]),0(%[from]),%[rem]\n"
120 "4: slgr %[size],%[rem]\n"
121 " j 6f\n"
122 "5: slgr %[size],%[size]\n"
123 "6:\n"
124 EX_TABLE(0b, 2b)
125 EX_TABLE(1b, 2b)
126 EX_TABLE(3b, 6b)
127 EX_TABLE(4b, 6b)
128 : [size] "+&a" (size), [to] "+&a" (to), [from] "+&a" (from), [rem] "=&a" (rem)
129 : [val] "a" (-4096UL), [spec] "d" (spec.val)
130 : "cc", "memory", "0");
131 return size;
132 }
133
raw_copy_to_user(void __user * to,const void * from,unsigned long n)134 unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n)
135 {
136 return raw_copy_to_user_key(to, from, n, 0);
137 }
138 EXPORT_SYMBOL(raw_copy_to_user);
139
_copy_to_user_key(void __user * to,const void * from,unsigned long n,unsigned long key)140 unsigned long _copy_to_user_key(void __user *to, const void *from,
141 unsigned long n, unsigned long key)
142 {
143 might_fault();
144 if (should_fail_usercopy())
145 return n;
146 instrument_copy_to_user(to, from, n);
147 return raw_copy_to_user_key(to, from, n, key);
148 }
149 EXPORT_SYMBOL(_copy_to_user_key);
150
__clear_user(void __user * to,unsigned long size)151 unsigned long __clear_user(void __user *to, unsigned long size)
152 {
153 unsigned long rem;
154 union oac spec = {
155 .oac1.as = PSW_BITS_AS_SECONDARY,
156 .oac1.a = 1,
157 };
158
159 asm volatile(
160 " lr 0,%[spec]\n"
161 "0: mvcos 0(%[to]),0(%[zeropg]),%[size]\n"
162 "1: jz 5f\n"
163 " algr %[size],%[val]\n"
164 " slgr %[to],%[val]\n"
165 " j 0b\n"
166 "2: la %[rem],4095(%[to])\n" /* rem = to + 4095 */
167 " nr %[rem],%[val]\n" /* rem = (to + 4095) & -4096 */
168 " slgr %[rem],%[to]\n"
169 " clgr %[size],%[rem]\n" /* copy crosses next page boundary? */
170 " jnh 6f\n"
171 "3: mvcos 0(%[to]),0(%[zeropg]),%[rem]\n"
172 "4: slgr %[size],%[rem]\n"
173 " j 6f\n"
174 "5: slgr %[size],%[size]\n"
175 "6:\n"
176 EX_TABLE(0b, 2b)
177 EX_TABLE(1b, 2b)
178 EX_TABLE(3b, 6b)
179 EX_TABLE(4b, 6b)
180 : [size] "+&a" (size), [to] "+&a" (to), [rem] "=&a" (rem)
181 : [val] "a" (-4096UL), [zeropg] "a" (empty_zero_page), [spec] "d" (spec.val)
182 : "cc", "memory", "0");
183 return size;
184 }
185 EXPORT_SYMBOL(__clear_user);
186