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/jump_label.h> 12 #include <linux/uaccess.h> 13 #include <linux/export.h> 14 #include <linux/errno.h> 15 #include <linux/mm.h> 16 #include <asm/mmu_context.h> 17 #include <asm/facility.h> 18 19 #ifdef CONFIG_DEBUG_ENTRY 20 void debug_user_asce(int exit) 21 { 22 unsigned long cr1, cr7; 23 24 __ctl_store(cr1, 1, 1); 25 __ctl_store(cr7, 7, 7); 26 if (cr1 == S390_lowcore.kernel_asce && cr7 == S390_lowcore.user_asce) 27 return; 28 panic("incorrect ASCE on kernel %s\n" 29 "cr1: %016lx cr7: %016lx\n" 30 "kernel: %016llx user: %016llx\n", 31 exit ? "exit" : "entry", cr1, cr7, 32 S390_lowcore.kernel_asce, S390_lowcore.user_asce); 33 34 } 35 #endif /*CONFIG_DEBUG_ENTRY */ 36 37 #ifndef CONFIG_HAVE_MARCH_Z10_FEATURES 38 static DEFINE_STATIC_KEY_FALSE(have_mvcos); 39 40 static int __init uaccess_init(void) 41 { 42 if (test_facility(27)) 43 static_branch_enable(&have_mvcos); 44 return 0; 45 } 46 early_initcall(uaccess_init); 47 48 static inline int copy_with_mvcos(void) 49 { 50 if (static_branch_likely(&have_mvcos)) 51 return 1; 52 return 0; 53 } 54 #else 55 static inline int copy_with_mvcos(void) 56 { 57 return 1; 58 } 59 #endif 60 61 static inline unsigned long copy_from_user_mvcos(void *x, const void __user *ptr, 62 unsigned long size) 63 { 64 unsigned long tmp1, tmp2; 65 union oac spec = { 66 .oac2.as = PSW_BITS_AS_SECONDARY, 67 .oac2.a = 1, 68 }; 69 70 tmp1 = -4096UL; 71 asm volatile( 72 " lr 0,%[spec]\n" 73 "0: .insn ss,0xc80000000000,0(%0,%2),0(%1),0\n" 74 "6: jz 4f\n" 75 "1: algr %0,%3\n" 76 " slgr %1,%3\n" 77 " slgr %2,%3\n" 78 " j 0b\n" 79 "2: la %4,4095(%1)\n"/* %4 = ptr + 4095 */ 80 " nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */ 81 " slgr %4,%1\n" 82 " clgr %0,%4\n" /* copy crosses next page boundary? */ 83 " jnh 5f\n" 84 "3: .insn ss,0xc80000000000,0(%4,%2),0(%1),0\n" 85 "7: slgr %0,%4\n" 86 " j 5f\n" 87 "4: slgr %0,%0\n" 88 "5:\n" 89 EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b) 90 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2) 91 : [spec] "d" (spec.val) 92 : "cc", "memory", "0"); 93 return size; 94 } 95 96 static inline unsigned long copy_from_user_mvcp(void *x, const void __user *ptr, 97 unsigned long size) 98 { 99 unsigned long tmp1, tmp2; 100 101 tmp1 = -256UL; 102 asm volatile( 103 " sacf 0\n" 104 "0: mvcp 0(%0,%2),0(%1),%3\n" 105 "7: jz 5f\n" 106 "1: algr %0,%3\n" 107 " la %1,256(%1)\n" 108 " la %2,256(%2)\n" 109 "2: mvcp 0(%0,%2),0(%1),%3\n" 110 "8: jnz 1b\n" 111 " j 5f\n" 112 "3: la %4,255(%1)\n" /* %4 = ptr + 255 */ 113 " lghi %3,-4096\n" 114 " nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */ 115 " slgr %4,%1\n" 116 " clgr %0,%4\n" /* copy crosses next page boundary? */ 117 " jnh 6f\n" 118 "4: mvcp 0(%4,%2),0(%1),%3\n" 119 "9: slgr %0,%4\n" 120 " j 6f\n" 121 "5: slgr %0,%0\n" 122 "6: sacf 768\n" 123 EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b) 124 EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b) 125 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2) 126 : : "cc", "memory"); 127 return size; 128 } 129 130 unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n) 131 { 132 if (copy_with_mvcos()) 133 return copy_from_user_mvcos(to, from, n); 134 return copy_from_user_mvcp(to, from, n); 135 } 136 EXPORT_SYMBOL(raw_copy_from_user); 137 138 static inline unsigned long copy_to_user_mvcos(void __user *ptr, const void *x, 139 unsigned long size) 140 { 141 unsigned long tmp1, tmp2; 142 union oac spec = { 143 .oac1.as = PSW_BITS_AS_SECONDARY, 144 .oac1.a = 1, 145 }; 146 147 tmp1 = -4096UL; 148 asm volatile( 149 " lr 0,%[spec]\n" 150 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n" 151 "6: jz 4f\n" 152 "1: algr %0,%3\n" 153 " slgr %1,%3\n" 154 " slgr %2,%3\n" 155 " j 0b\n" 156 "2: la %4,4095(%1)\n"/* %4 = ptr + 4095 */ 157 " nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */ 158 " slgr %4,%1\n" 159 " clgr %0,%4\n" /* copy crosses next page boundary? */ 160 " jnh 5f\n" 161 "3: .insn ss,0xc80000000000,0(%4,%1),0(%2),0\n" 162 "7: slgr %0,%4\n" 163 " j 5f\n" 164 "4: slgr %0,%0\n" 165 "5:\n" 166 EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b) 167 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2) 168 : [spec] "d" (spec.val) 169 : "cc", "memory", "0"); 170 return size; 171 } 172 173 static inline unsigned long copy_to_user_mvcs(void __user *ptr, const void *x, 174 unsigned long size) 175 { 176 unsigned long tmp1, tmp2; 177 178 tmp1 = -256UL; 179 asm volatile( 180 " sacf 0\n" 181 "0: mvcs 0(%0,%1),0(%2),%3\n" 182 "7: jz 5f\n" 183 "1: algr %0,%3\n" 184 " la %1,256(%1)\n" 185 " la %2,256(%2)\n" 186 "2: mvcs 0(%0,%1),0(%2),%3\n" 187 "8: jnz 1b\n" 188 " j 5f\n" 189 "3: la %4,255(%1)\n" /* %4 = ptr + 255 */ 190 " lghi %3,-4096\n" 191 " nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */ 192 " slgr %4,%1\n" 193 " clgr %0,%4\n" /* copy crosses next page boundary? */ 194 " jnh 6f\n" 195 "4: mvcs 0(%4,%1),0(%2),%3\n" 196 "9: slgr %0,%4\n" 197 " j 6f\n" 198 "5: slgr %0,%0\n" 199 "6: sacf 768\n" 200 EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b) 201 EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b) 202 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2) 203 : : "cc", "memory"); 204 return size; 205 } 206 207 unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n) 208 { 209 if (copy_with_mvcos()) 210 return copy_to_user_mvcos(to, from, n); 211 return copy_to_user_mvcs(to, from, n); 212 } 213 EXPORT_SYMBOL(raw_copy_to_user); 214 215 static inline unsigned long clear_user_mvcos(void __user *to, unsigned long size) 216 { 217 unsigned long tmp1, tmp2; 218 union oac spec = { 219 .oac1.as = PSW_BITS_AS_SECONDARY, 220 .oac1.a = 1, 221 }; 222 223 tmp1 = -4096UL; 224 asm volatile( 225 " lr 0,%[spec]\n" 226 "0: .insn ss,0xc80000000000,0(%0,%1),0(%4),0\n" 227 " jz 4f\n" 228 "1: algr %0,%2\n" 229 " slgr %1,%2\n" 230 " j 0b\n" 231 "2: la %3,4095(%1)\n"/* %4 = to + 4095 */ 232 " nr %3,%2\n" /* %4 = (to + 4095) & -4096 */ 233 " slgr %3,%1\n" 234 " clgr %0,%3\n" /* copy crosses next page boundary? */ 235 " jnh 5f\n" 236 "3: .insn ss,0xc80000000000,0(%3,%1),0(%4),0\n" 237 " slgr %0,%3\n" 238 " j 5f\n" 239 "4: slgr %0,%0\n" 240 "5:\n" 241 EX_TABLE(0b,2b) EX_TABLE(3b,5b) 242 : "+a" (size), "+a" (to), "+a" (tmp1), "=a" (tmp2) 243 : "a" (empty_zero_page), [spec] "d" (spec.val) 244 : "cc", "memory", "0"); 245 return size; 246 } 247 248 static inline unsigned long clear_user_xc(void __user *to, unsigned long size) 249 { 250 unsigned long tmp1, tmp2; 251 252 asm volatile( 253 " sacf 256\n" 254 " aghi %0,-1\n" 255 " jo 5f\n" 256 " bras %3,3f\n" 257 " xc 0(1,%1),0(%1)\n" 258 "0: aghi %0,257\n" 259 " la %2,255(%1)\n" /* %2 = ptr + 255 */ 260 " srl %2,12\n" 261 " sll %2,12\n" /* %2 = (ptr + 255) & -4096 */ 262 " slgr %2,%1\n" 263 " clgr %0,%2\n" /* clear crosses next page boundary? */ 264 " jnh 5f\n" 265 " aghi %2,-1\n" 266 "1: ex %2,0(%3)\n" 267 " aghi %2,1\n" 268 " slgr %0,%2\n" 269 " j 5f\n" 270 "2: xc 0(256,%1),0(%1)\n" 271 " la %1,256(%1)\n" 272 "3: aghi %0,-256\n" 273 " jnm 2b\n" 274 "4: ex %0,0(%3)\n" 275 "5: slgr %0,%0\n" 276 "6: sacf 768\n" 277 EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b) 278 : "+a" (size), "+a" (to), "=a" (tmp1), "=a" (tmp2) 279 : : "cc", "memory"); 280 return size; 281 } 282 283 unsigned long __clear_user(void __user *to, unsigned long size) 284 { 285 if (copy_with_mvcos()) 286 return clear_user_mvcos(to, size); 287 return clear_user_xc(to, size); 288 } 289 EXPORT_SYMBOL(__clear_user); 290