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
debug_user_asce(int exit)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
_copy_from_user_key(void * to,const void __user * from,unsigned long n,unsigned long key)34 unsigned long _copy_from_user_key(void *to, const void __user *from,
35 unsigned long n, unsigned long key)
36 {
37 unsigned long res = n;
38
39 might_fault();
40 if (!should_fail_usercopy()) {
41 instrument_copy_from_user_before(to, from, n);
42 res = raw_copy_from_user_key(to, from, n, key);
43 instrument_copy_from_user_after(to, from, n, res);
44 }
45 if (unlikely(res))
46 memset(to + (n - res), 0, res);
47 return res;
48 }
49 EXPORT_SYMBOL(_copy_from_user_key);
50
_copy_to_user_key(void __user * to,const void * from,unsigned long n,unsigned long key)51 unsigned long _copy_to_user_key(void __user *to, const void *from,
52 unsigned long n, unsigned long key)
53 {
54 might_fault();
55 if (should_fail_usercopy())
56 return n;
57 instrument_copy_to_user(to, from, n);
58 return raw_copy_to_user_key(to, from, n, key);
59 }
60 EXPORT_SYMBOL(_copy_to_user_key);
61
__clear_user(void __user * to,unsigned long size)62 unsigned long __clear_user(void __user *to, unsigned long size)
63 {
64 unsigned long rem;
65 union oac spec = {
66 .oac1.as = PSW_BITS_AS_SECONDARY,
67 .oac1.a = 1,
68 };
69
70 asm volatile(
71 " lr 0,%[spec]\n"
72 "0: mvcos 0(%[to]),0(%[zeropg]),%[size]\n"
73 "1: jz 5f\n"
74 " algr %[size],%[val]\n"
75 " slgr %[to],%[val]\n"
76 " j 0b\n"
77 "2: la %[rem],4095(%[to])\n" /* rem = to + 4095 */
78 " nr %[rem],%[val]\n" /* rem = (to + 4095) & -4096 */
79 " slgr %[rem],%[to]\n"
80 " clgr %[size],%[rem]\n" /* copy crosses next page boundary? */
81 " jnh 6f\n"
82 "3: mvcos 0(%[to]),0(%[zeropg]),%[rem]\n"
83 "4: slgr %[size],%[rem]\n"
84 " j 6f\n"
85 "5: slgr %[size],%[size]\n"
86 "6:\n"
87 EX_TABLE(0b, 2b)
88 EX_TABLE(1b, 2b)
89 EX_TABLE(3b, 6b)
90 EX_TABLE(4b, 6b)
91 : [size] "+&a" (size), [to] "+&a" (to), [rem] "=&a" (rem)
92 : [val] "a" (-4096UL), [zeropg] "a" (empty_zero_page), [spec] "d" (spec.val)
93 : "cc", "memory", "0");
94 return size;
95 }
96 EXPORT_SYMBOL(__clear_user);
97