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 17void 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 33static 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 72unsigned 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} 76EXPORT_SYMBOL(raw_copy_from_user); 77 78unsigned 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} 93EXPORT_SYMBOL(_copy_from_user_key); 94 95static 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 134unsigned 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} 138EXPORT_SYMBOL(raw_copy_to_user); 139 140unsigned 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} 149EXPORT_SYMBOL(_copy_to_user_key); 150 151unsigned 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} 185EXPORT_SYMBOL(__clear_user); 186