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
18void 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 == S390_lowcore.kernel_asce.val && cr7.val == S390_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	      S390_lowcore.kernel_asce.val, S390_lowcore.user_asce.val);
31}
32#endif /*CONFIG_DEBUG_ENTRY */
33
34static 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", "0");
70	return size;
71}
72
73unsigned 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}
77EXPORT_SYMBOL(raw_copy_from_user);
78
79unsigned 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}
94EXPORT_SYMBOL(_copy_from_user_key);
95
96static 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", "0");
132	return size;
133}
134
135unsigned 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}
139EXPORT_SYMBOL(raw_copy_to_user);
140
141unsigned 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}
150EXPORT_SYMBOL(_copy_to_user_key);
151
152unsigned 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", "0");
184	return size;
185}
186EXPORT_SYMBOL(__clear_user);
187