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 #include <asm/ctlreg.h>
16
17 #ifdef CONFIG_DEBUG_ENTRY
18 void debug_user_asce(int exit)
19 {
20 struct ctlreg cr1, cr7;
21
22 local_ctl_store(1, &cr1);
23 local_ctl_store(7, &cr7);
24 if (cr1.val == get_lowcore()->kernel_asce.val && cr7.val == get_lowcore()->user_asce.val)
25 return;
26 panic("incorrect ASCE on kernel %s\n"
27 "cr1: %016lx cr7: %016lx\n"
28 "kernel: %016lx user: %016lx\n",
29 exit ? "exit" : "entry", cr1.val, cr7.val,
30 get_lowcore()->kernel_asce.val, get_lowcore()->user_asce.val);
31 }
32 #endif /*CONFIG_DEBUG_ENTRY */
33
34 static unsigned long raw_copy_from_user_key(void *to, const void __user *from,
35 unsigned long size, unsigned long key)
36 {
37 unsigned long rem;
38 union oac spec = {
39 .oac2.key = key,
40 .oac2.as = PSW_BITS_AS_SECONDARY,
41 .oac2.k = 1,
42 .oac2.a = 1,
43 };
44
45 asm volatile(
46 " lr 0,%[spec]\n"
47 "0: mvcos 0(%[to]),0(%[from]),%[size]\n"
48 "1: jz 5f\n"
49 " algr %[size],%[val]\n"
50 " slgr %[from],%[val]\n"
51 " slgr %[to],%[val]\n"
52 " j 0b\n"
53 "2: la %[rem],4095(%[from])\n" /* rem = from + 4095 */
54 " nr %[rem],%[val]\n" /* rem = (from + 4095) & -4096 */
55 " slgr %[rem],%[from]\n"
56 " clgr %[size],%[rem]\n" /* copy crosses next page boundary? */
57 " jnh 6f\n"
58 "3: mvcos 0(%[to]),0(%[from]),%[rem]\n"
59 "4: slgr %[size],%[rem]\n"
60 " j 6f\n"
61 "5: slgr %[size],%[size]\n"
62 "6:\n"
63 EX_TABLE(0b, 2b)
64 EX_TABLE(1b, 2b)
65 EX_TABLE(3b, 6b)
66 EX_TABLE(4b, 6b)
67 : [size] "+&a" (size), [from] "+&a" (from), [to] "+&a" (to), [rem] "=&a" (rem)
68 : [val] "a" (-4096UL), [spec] "d" (spec.val)
69 : "cc", "memory", "");
70 return size;
71 }
72
73 unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n)
74 {
75 return raw_copy_from_user_key(to, from, n, 0);
76 }
77 EXPORT_SYMBOL(raw_copy_from_user);
78
79 unsigned long _copy_from_user_key(void *to, const void __user *from,
80 unsigned long n, unsigned long key)
81 {
82 unsigned long res = n;
83
84 might_fault();
85 if (!should_fail_usercopy()) {
86 instrument_copy_from_user_before(to, from, n);
87 res = raw_copy_from_user_key(to, from, n, key);
88 instrument_copy_from_user_after(to, from, n, res);
89 }
90 if (unlikely(res))
91 memset(to + (n - res), 0, res);
92 return res;
93 }
94 EXPORT_SYMBOL(_copy_from_user_key);
95
96 static unsigned long raw_copy_to_user_key(void __user *to, const void *from,
97 unsigned long size, unsigned long key)
98 {
99 unsigned long rem;
100 union oac spec = {
101 .oac1.key = key,
102 .oac1.as = PSW_BITS_AS_SECONDARY,
103 .oac1.k = 1,
104 .oac1.a = 1,
105 };
106
107 asm volatile(
108 " lr 0,%[spec]\n"
109 "0: mvcos 0(%[to]),0(%[from]),%[size]\n"
110 "1: jz 5f\n"
111 " algr %[size],%[val]\n"
112 " slgr %[to],%[val]\n"
113 " slgr %[from],%[val]\n"
114 " j 0b\n"
115 "2: la %[rem],4095(%[to])\n" /* rem = to + 4095 */
116 " nr %[rem],%[val]\n" /* rem = (to + 4095) & -4096 */
117 " slgr %[rem],%[to]\n"
118 " clgr %[size],%[rem]\n" /* copy crosses next page boundary? */
119 " jnh 6f\n"
120 "3: mvcos 0(%[to]),0(%[from]),%[rem]\n"
121 "4: slgr %[size],%[rem]\n"
122 " j 6f\n"
123 "5: slgr %[size],%[size]\n"
124 "6:\n"
125 EX_TABLE(0b, 2b)
126 EX_TABLE(1b, 2b)
127 EX_TABLE(3b, 6b)
128 EX_TABLE(4b, 6b)
129 : [size] "+&a" (size), [to] "+&a" (to), [from] "+&a" (from), [rem] "=&a" (rem)
130 : [val] "a" (-4096UL), [spec] "d" (spec.val)
131 : "cc", "memory", "");
132 return size;
133 }
134
135 unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n)
136 {
137 return raw_copy_to_user_key(to, from, n, 0);
138 }
139 EXPORT_SYMBOL(raw_copy_to_user);
140
141 unsigned long _copy_to_user_key(void __user *to, const void *from,
142 unsigned long n, unsigned long key)
143 {
144 might_fault();
145 if (should_fail_usercopy())
146 return n;
147 instrument_copy_to_user(to, from, n);
148 return raw_copy_to_user_key(to, from, n, key);
149 }
150 EXPORT_SYMBOL(_copy_to_user_key);
151
152 unsigned long __clear_user(void __user *to, unsigned long size)
153 {
154 unsigned long rem;
155 union oac spec = {
156 .oac1.as = PSW_BITS_AS_SECONDARY,
157 .oac1.a = 1,
158 };
159
160 asm volatile(
161 " lr 0,%[spec]\n"
162 "0: mvcos 0(%[to]),0(%[zeropg]),%[size]\n"
163 "1: jz 5f\n"
164 " algr %[size],%[val]\n"
165 " slgr %[to],%[val]\n"
166 " j 0b\n"
167 "2: la %[rem],4095(%[to])\n" /* rem = to + 4095 */
168 " nr %[rem],%[val]\n" /* rem = (to + 4095) & -4096 */
169 " slgr %[rem],%[to]\n"
170 " clgr %[size],%[rem]\n" /* copy crosses next page boundary? */
171 " jnh 6f\n"
172 "3: mvcos 0(%[to]),0(%[zeropg]),%[rem]\n"
173 "4: slgr %[size],%[rem]\n"
174 " j 6f\n"
175 "5: slgr %[size],%[size]\n"
176 "6:\n"
177 EX_TABLE(0b, 2b)
178 EX_TABLE(1b, 2b)
179 EX_TABLE(3b, 6b)
180 EX_TABLE(4b, 6b)
181 : [size] "+&a" (size), [to] "+&a" (to), [rem] "=&a" (rem)
182 : [val] "a" (-4096UL), [zeropg] "a" (empty_zero_page), [spec] "d" (spec.val)
183 : "cc", "memory", "");
184 return size;
185 }
186 EXPORT_SYMBOL(__clear_user);
187
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