1/* SPDX-License-Identifier: GPL-2.0 */ 2#ifndef _ASM_X86_PERCPU_H 3#define _ASM_X86_PERCPU_H 4 5#ifdef CONFIG_X86_64 6#define __percpu_seg gs 7#else 8#define __percpu_seg fs 9#endif 10 11#ifdef __ASSEMBLY__ 12 13#ifdef CONFIG_SMP 14#define PER_CPU_VAR(var) %__percpu_seg:var 15#else /* ! SMP */ 16#define PER_CPU_VAR(var) var 17#endif /* SMP */ 18 19#ifdef CONFIG_X86_64_SMP 20#define INIT_PER_CPU_VAR(var) init_per_cpu__##var 21#else 22#define INIT_PER_CPU_VAR(var) var 23#endif 24 25#else /* ...!ASSEMBLY */ 26 27#include <linux/kernel.h> 28#include <linux/stringify.h> 29 30#ifdef CONFIG_SMP 31#define __percpu_prefix "%%"__stringify(__percpu_seg)":" 32#define __my_cpu_offset this_cpu_read(this_cpu_off) 33 34/* 35 * Compared to the generic __my_cpu_offset version, the following 36 * saves one instruction and avoids clobbering a temp register. 37 */ 38#define arch_raw_cpu_ptr(ptr) \ 39({ \ 40 unsigned long tcp_ptr__; \ 41 asm ("add " __percpu_arg(1) ", %0" \ 42 : "=r" (tcp_ptr__) \ 43 : "m" (this_cpu_off), "0" (ptr)); \ 44 (typeof(*(ptr)) __kernel __force *)tcp_ptr__; \ 45}) 46#else 47#define __percpu_prefix "" 48#endif 49 50#define __percpu_arg(x) __percpu_prefix "%" #x 51 52/* 53 * Initialized pointers to per-cpu variables needed for the boot 54 * processor need to use these macros to get the proper address 55 * offset from __per_cpu_load on SMP. 56 * 57 * There also must be an entry in vmlinux_64.lds.S 58 */ 59#define DECLARE_INIT_PER_CPU(var) \ 60 extern typeof(var) init_per_cpu_var(var) 61 62#ifdef CONFIG_X86_64_SMP 63#define init_per_cpu_var(var) init_per_cpu__##var 64#else 65#define init_per_cpu_var(var) var 66#endif 67 68/* For arch-specific code, we can use direct single-insn ops (they 69 * don't give an lvalue though). */ 70 71#define __pcpu_type_1 u8 72#define __pcpu_type_2 u16 73#define __pcpu_type_4 u32 74#define __pcpu_type_8 u64 75 76#define __pcpu_cast_1(val) ((u8)(((unsigned long) val) & 0xff)) 77#define __pcpu_cast_2(val) ((u16)(((unsigned long) val) & 0xffff)) 78#define __pcpu_cast_4(val) ((u32)(((unsigned long) val) & 0xffffffff)) 79#define __pcpu_cast_8(val) ((u64)(val)) 80 81#define __pcpu_op1_1(op, dst) op "b " dst 82#define __pcpu_op1_2(op, dst) op "w " dst 83#define __pcpu_op1_4(op, dst) op "l " dst 84#define __pcpu_op1_8(op, dst) op "q " dst 85 86#define __pcpu_op2_1(op, src, dst) op "b " src ", " dst 87#define __pcpu_op2_2(op, src, dst) op "w " src ", " dst 88#define __pcpu_op2_4(op, src, dst) op "l " src ", " dst 89#define __pcpu_op2_8(op, src, dst) op "q " src ", " dst 90 91#define __pcpu_reg_1(mod, x) mod "q" (x) 92#define __pcpu_reg_2(mod, x) mod "r" (x) 93#define __pcpu_reg_4(mod, x) mod "r" (x) 94#define __pcpu_reg_8(mod, x) mod "r" (x) 95 96#define __pcpu_reg_imm_1(x) "qi" (x) 97#define __pcpu_reg_imm_2(x) "ri" (x) 98#define __pcpu_reg_imm_4(x) "ri" (x) 99#define __pcpu_reg_imm_8(x) "re" (x) 100 101#define percpu_to_op(size, qual, op, _var, _val) \ 102do { \ 103 __pcpu_type_##size pto_val__ = __pcpu_cast_##size(_val); \ 104 if (0) { \ 105 typeof(_var) pto_tmp__; \ 106 pto_tmp__ = (_val); \ 107 (void)pto_tmp__; \ 108 } \ 109 asm qual(__pcpu_op2_##size(op, "%[val]", __percpu_arg([var])) \ 110 : [var] "+m" (_var) \ 111 : [val] __pcpu_reg_imm_##size(pto_val__)); \ 112} while (0) 113 114#define percpu_unary_op(size, qual, op, _var) \ 115({ \ 116 asm qual (__pcpu_op1_##size(op, __percpu_arg([var])) \ 117 : [var] "+m" (_var)); \ 118}) 119 120/* 121 * Generate a percpu add to memory instruction and optimize code 122 * if one is added or subtracted. 123 */ 124#define percpu_add_op(size, qual, var, val) \ 125do { \ 126 const int pao_ID__ = (__builtin_constant_p(val) && \ 127 ((val) == 1 || (val) == -1)) ? \ 128 (int)(val) : 0; \ 129 if (0) { \ 130 typeof(var) pao_tmp__; \ 131 pao_tmp__ = (val); \ 132 (void)pao_tmp__; \ 133 } \ 134 if (pao_ID__ == 1) \ 135 percpu_unary_op(size, qual, "inc", var); \ 136 else if (pao_ID__ == -1) \ 137 percpu_unary_op(size, qual, "dec", var); \ 138 else \ 139 percpu_to_op(size, qual, "add", var, val); \ 140} while (0) 141 142#define percpu_from_op(size, qual, op, _var) \ 143({ \ 144 __pcpu_type_##size pfo_val__; \ 145 asm qual (__pcpu_op2_##size(op, __percpu_arg([var]), "%[val]") \ 146 : [val] __pcpu_reg_##size("=", pfo_val__) \ 147 : [var] "m" (_var)); \ 148 (typeof(_var))(unsigned long) pfo_val__; \ 149}) 150 151#define percpu_stable_op(size, op, _var) \ 152({ \ 153 __pcpu_type_##size pfo_val__; \ 154 asm(__pcpu_op2_##size(op, __percpu_arg(P[var]), "%[val]") \ 155 : [val] __pcpu_reg_##size("=", pfo_val__) \ 156 : [var] "p" (&(_var))); \ 157 (typeof(_var))(unsigned long) pfo_val__; \ 158}) 159 160/* 161 * Add return operation 162 */ 163#define percpu_add_return_op(size, qual, _var, _val) \ 164({ \ 165 __pcpu_type_##size paro_tmp__ = __pcpu_cast_##size(_val); \ 166 asm qual (__pcpu_op2_##size("xadd", "%[tmp]", \ 167 __percpu_arg([var])) \ 168 : [tmp] __pcpu_reg_##size("+", paro_tmp__), \ 169 [var] "+m" (_var) \ 170 : : "memory"); \ 171 (typeof(_var))(unsigned long) (paro_tmp__ + _val); \ 172}) 173 174/* 175 * xchg is implemented using cmpxchg without a lock prefix. xchg is 176 * expensive due to the implied lock prefix. The processor cannot prefetch 177 * cachelines if xchg is used. 178 */ 179#define percpu_xchg_op(size, qual, _var, _nval) \ 180({ \ 181 __pcpu_type_##size pxo_old__; \ 182 __pcpu_type_##size pxo_new__ = __pcpu_cast_##size(_nval); \ 183 asm qual (__pcpu_op2_##size("mov", __percpu_arg([var]), \ 184 "%[oval]") \ 185 "\n1:\t" \ 186 __pcpu_op2_##size("cmpxchg", "%[nval]", \ 187 __percpu_arg([var])) \ 188 "\n\tjnz 1b" \ 189 : [oval] "=&a" (pxo_old__), \ 190 [var] "+m" (_var) \ 191 : [nval] __pcpu_reg_##size(, pxo_new__) \ 192 : "memory"); \ 193 (typeof(_var))(unsigned long) pxo_old__; \ 194}) 195 196/* 197 * cmpxchg has no such implied lock semantics as a result it is much 198 * more efficient for cpu local operations. 199 */ 200#define percpu_cmpxchg_op(size, qual, _var, _oval, _nval) \ 201({ \ 202 __pcpu_type_##size pco_old__ = __pcpu_cast_##size(_oval); \ 203 __pcpu_type_##size pco_new__ = __pcpu_cast_##size(_nval); \ 204 asm qual (__pcpu_op2_##size("cmpxchg", "%[nval]", \ 205 __percpu_arg([var])) \ 206 : [oval] "+a" (pco_old__), \ 207 [var] "+m" (_var) \ 208 : [nval] __pcpu_reg_##size(, pco_new__) \ 209 : "memory"); \ 210 (typeof(_var))(unsigned long) pco_old__; \ 211}) 212 213#if defined(CONFIG_X86_32) && !defined(CONFIG_UML) 214#define percpu_cmpxchg64_op(size, qual, _var, _oval, _nval) \ 215({ \ 216 union { \ 217 u64 var; \ 218 struct { \ 219 u32 low, high; \ 220 }; \ 221 } old__, new__; \ 222 \ 223 old__.var = _oval; \ 224 new__.var = _nval; \ 225 \ 226 asm qual (ALTERNATIVE("leal %P[var], %%esi; call this_cpu_cmpxchg8b_emu", \ 227 "cmpxchg8b " __percpu_arg([var]), X86_FEATURE_CX8) \ 228 : [var] "+m" (_var), \ 229 "+a" (old__.low), \ 230 "+d" (old__.high) \ 231 : "b" (new__.low), \ 232 "c" (new__.high) \ 233 : "memory", "esi"); \ 234 \ 235 old__.var; \ 236}) 237 238#define raw_cpu_cmpxchg64(pcp, oval, nval) percpu_cmpxchg64_op(8, , pcp, oval, nval) 239#define this_cpu_cmpxchg64(pcp, oval, nval) percpu_cmpxchg64_op(8, volatile, pcp, oval, nval) 240#endif 241 242#ifdef CONFIG_X86_64 243#define raw_cpu_cmpxchg64(pcp, oval, nval) percpu_cmpxchg_op(8, , pcp, oval, nval); 244#define this_cpu_cmpxchg64(pcp, oval, nval) percpu_cmpxchg_op(8, volatile, pcp, oval, nval); 245 246#define percpu_cmpxchg128_op(size, qual, _var, _oval, _nval) \ 247({ \ 248 union { \ 249 u128 var; \ 250 struct { \ 251 u64 low, high; \ 252 }; \ 253 } old__, new__; \ 254 \ 255 old__.var = _oval; \ 256 new__.var = _nval; \ 257 \ 258 asm qual (ALTERNATIVE("leaq %P[var], %%rsi; call this_cpu_cmpxchg16b_emu", \ 259 "cmpxchg16b " __percpu_arg([var]), X86_FEATURE_CX16) \ 260 : [var] "+m" (_var), \ 261 "+a" (old__.low), \ 262 "+d" (old__.high) \ 263 : "b" (new__.low), \ 264 "c" (new__.high) \ 265 : "memory", "rsi"); \ 266 \ 267 old__.var; \ 268}) 269 270#define raw_cpu_cmpxchg128(pcp, oval, nval) percpu_cmpxchg128_op(16, , pcp, oval, nval) 271#define this_cpu_cmpxchg128(pcp, oval, nval) percpu_cmpxchg128_op(16, volatile, pcp, oval, nval) 272#endif 273 274/* 275 * this_cpu_read() makes gcc load the percpu variable every time it is 276 * accessed while this_cpu_read_stable() allows the value to be cached. 277 * this_cpu_read_stable() is more efficient and can be used if its value 278 * is guaranteed to be valid across cpus. The current users include 279 * get_current() and get_thread_info() both of which are actually 280 * per-thread variables implemented as per-cpu variables and thus 281 * stable for the duration of the respective task. 282 */ 283#define this_cpu_read_stable_1(pcp) percpu_stable_op(1, "mov", pcp) 284#define this_cpu_read_stable_2(pcp) percpu_stable_op(2, "mov", pcp) 285#define this_cpu_read_stable_4(pcp) percpu_stable_op(4, "mov", pcp) 286#define this_cpu_read_stable_8(pcp) percpu_stable_op(8, "mov", pcp) 287#define this_cpu_read_stable(pcp) __pcpu_size_call_return(this_cpu_read_stable_, pcp) 288 289#define raw_cpu_read_1(pcp) percpu_from_op(1, , "mov", pcp) 290#define raw_cpu_read_2(pcp) percpu_from_op(2, , "mov", pcp) 291#define raw_cpu_read_4(pcp) percpu_from_op(4, , "mov", pcp) 292 293#define raw_cpu_write_1(pcp, val) percpu_to_op(1, , "mov", (pcp), val) 294#define raw_cpu_write_2(pcp, val) percpu_to_op(2, , "mov", (pcp), val) 295#define raw_cpu_write_4(pcp, val) percpu_to_op(4, , "mov", (pcp), val) 296#define raw_cpu_add_1(pcp, val) percpu_add_op(1, , (pcp), val) 297#define raw_cpu_add_2(pcp, val) percpu_add_op(2, , (pcp), val) 298#define raw_cpu_add_4(pcp, val) percpu_add_op(4, , (pcp), val) 299#define raw_cpu_and_1(pcp, val) percpu_to_op(1, , "and", (pcp), val) 300#define raw_cpu_and_2(pcp, val) percpu_to_op(2, , "and", (pcp), val) 301#define raw_cpu_and_4(pcp, val) percpu_to_op(4, , "and", (pcp), val) 302#define raw_cpu_or_1(pcp, val) percpu_to_op(1, , "or", (pcp), val) 303#define raw_cpu_or_2(pcp, val) percpu_to_op(2, , "or", (pcp), val) 304#define raw_cpu_or_4(pcp, val) percpu_to_op(4, , "or", (pcp), val) 305 306/* 307 * raw_cpu_xchg() can use a load-store since it is not required to be 308 * IRQ-safe. 309 */ 310#define raw_percpu_xchg_op(var, nval) \ 311({ \ 312 typeof(var) pxo_ret__ = raw_cpu_read(var); \ 313 raw_cpu_write(var, (nval)); \ 314 pxo_ret__; \ 315}) 316 317#define raw_cpu_xchg_1(pcp, val) raw_percpu_xchg_op(pcp, val) 318#define raw_cpu_xchg_2(pcp, val) raw_percpu_xchg_op(pcp, val) 319#define raw_cpu_xchg_4(pcp, val) raw_percpu_xchg_op(pcp, val) 320 321#define this_cpu_read_1(pcp) percpu_from_op(1, volatile, "mov", pcp) 322#define this_cpu_read_2(pcp) percpu_from_op(2, volatile, "mov", pcp) 323#define this_cpu_read_4(pcp) percpu_from_op(4, volatile, "mov", pcp) 324#define this_cpu_write_1(pcp, val) percpu_to_op(1, volatile, "mov", (pcp), val) 325#define this_cpu_write_2(pcp, val) percpu_to_op(2, volatile, "mov", (pcp), val) 326#define this_cpu_write_4(pcp, val) percpu_to_op(4, volatile, "mov", (pcp), val) 327#define this_cpu_add_1(pcp, val) percpu_add_op(1, volatile, (pcp), val) 328#define this_cpu_add_2(pcp, val) percpu_add_op(2, volatile, (pcp), val) 329#define this_cpu_add_4(pcp, val) percpu_add_op(4, volatile, (pcp), val) 330#define this_cpu_and_1(pcp, val) percpu_to_op(1, volatile, "and", (pcp), val) 331#define this_cpu_and_2(pcp, val) percpu_to_op(2, volatile, "and", (pcp), val) 332#define this_cpu_and_4(pcp, val) percpu_to_op(4, volatile, "and", (pcp), val) 333#define this_cpu_or_1(pcp, val) percpu_to_op(1, volatile, "or", (pcp), val) 334#define this_cpu_or_2(pcp, val) percpu_to_op(2, volatile, "or", (pcp), val) 335#define this_cpu_or_4(pcp, val) percpu_to_op(4, volatile, "or", (pcp), val) 336#define this_cpu_xchg_1(pcp, nval) percpu_xchg_op(1, volatile, pcp, nval) 337#define this_cpu_xchg_2(pcp, nval) percpu_xchg_op(2, volatile, pcp, nval) 338#define this_cpu_xchg_4(pcp, nval) percpu_xchg_op(4, volatile, pcp, nval) 339 340#define raw_cpu_add_return_1(pcp, val) percpu_add_return_op(1, , pcp, val) 341#define raw_cpu_add_return_2(pcp, val) percpu_add_return_op(2, , pcp, val) 342#define raw_cpu_add_return_4(pcp, val) percpu_add_return_op(4, , pcp, val) 343#define raw_cpu_cmpxchg_1(pcp, oval, nval) percpu_cmpxchg_op(1, , pcp, oval, nval) 344#define raw_cpu_cmpxchg_2(pcp, oval, nval) percpu_cmpxchg_op(2, , pcp, oval, nval) 345#define raw_cpu_cmpxchg_4(pcp, oval, nval) percpu_cmpxchg_op(4, , pcp, oval, nval) 346 347#define this_cpu_add_return_1(pcp, val) percpu_add_return_op(1, volatile, pcp, val) 348#define this_cpu_add_return_2(pcp, val) percpu_add_return_op(2, volatile, pcp, val) 349#define this_cpu_add_return_4(pcp, val) percpu_add_return_op(4, volatile, pcp, val) 350#define this_cpu_cmpxchg_1(pcp, oval, nval) percpu_cmpxchg_op(1, volatile, pcp, oval, nval) 351#define this_cpu_cmpxchg_2(pcp, oval, nval) percpu_cmpxchg_op(2, volatile, pcp, oval, nval) 352#define this_cpu_cmpxchg_4(pcp, oval, nval) percpu_cmpxchg_op(4, volatile, pcp, oval, nval) 353 354/* 355 * Per cpu atomic 64 bit operations are only available under 64 bit. 356 * 32 bit must fall back to generic operations. 357 */ 358#ifdef CONFIG_X86_64 359#define raw_cpu_read_8(pcp) percpu_from_op(8, , "mov", pcp) 360#define raw_cpu_write_8(pcp, val) percpu_to_op(8, , "mov", (pcp), val) 361#define raw_cpu_add_8(pcp, val) percpu_add_op(8, , (pcp), val) 362#define raw_cpu_and_8(pcp, val) percpu_to_op(8, , "and", (pcp), val) 363#define raw_cpu_or_8(pcp, val) percpu_to_op(8, , "or", (pcp), val) 364#define raw_cpu_add_return_8(pcp, val) percpu_add_return_op(8, , pcp, val) 365#define raw_cpu_xchg_8(pcp, nval) raw_percpu_xchg_op(pcp, nval) 366#define raw_cpu_cmpxchg_8(pcp, oval, nval) percpu_cmpxchg_op(8, , pcp, oval, nval) 367 368#define this_cpu_read_8(pcp) percpu_from_op(8, volatile, "mov", pcp) 369#define this_cpu_write_8(pcp, val) percpu_to_op(8, volatile, "mov", (pcp), val) 370#define this_cpu_add_8(pcp, val) percpu_add_op(8, volatile, (pcp), val) 371#define this_cpu_and_8(pcp, val) percpu_to_op(8, volatile, "and", (pcp), val) 372#define this_cpu_or_8(pcp, val) percpu_to_op(8, volatile, "or", (pcp), val) 373#define this_cpu_add_return_8(pcp, val) percpu_add_return_op(8, volatile, pcp, val) 374#define this_cpu_xchg_8(pcp, nval) percpu_xchg_op(8, volatile, pcp, nval) 375#define this_cpu_cmpxchg_8(pcp, oval, nval) percpu_cmpxchg_op(8, volatile, pcp, oval, nval) 376#endif 377 378static __always_inline bool x86_this_cpu_constant_test_bit(unsigned int nr, 379 const unsigned long __percpu *addr) 380{ 381 unsigned long __percpu *a = 382 (unsigned long __percpu *)addr + nr / BITS_PER_LONG; 383 384#ifdef CONFIG_X86_64 385 return ((1UL << (nr % BITS_PER_LONG)) & raw_cpu_read_8(*a)) != 0; 386#else 387 return ((1UL << (nr % BITS_PER_LONG)) & raw_cpu_read_4(*a)) != 0; 388#endif 389} 390 391static inline bool x86_this_cpu_variable_test_bit(int nr, 392 const unsigned long __percpu *addr) 393{ 394 bool oldbit; 395 396 asm volatile("btl "__percpu_arg(2)",%1" 397 CC_SET(c) 398 : CC_OUT(c) (oldbit) 399 : "m" (*(unsigned long __percpu *)addr), "Ir" (nr)); 400 401 return oldbit; 402} 403 404#define x86_this_cpu_test_bit(nr, addr) \ 405 (__builtin_constant_p((nr)) \ 406 ? x86_this_cpu_constant_test_bit((nr), (addr)) \ 407 : x86_this_cpu_variable_test_bit((nr), (addr))) 408 409 410#include <asm-generic/percpu.h> 411 412/* We can use this directly for local CPU (faster). */ 413DECLARE_PER_CPU_READ_MOSTLY(unsigned long, this_cpu_off); 414 415#endif /* !__ASSEMBLY__ */ 416 417#ifdef CONFIG_SMP 418 419/* 420 * Define the "EARLY_PER_CPU" macros. These are used for some per_cpu 421 * variables that are initialized and accessed before there are per_cpu 422 * areas allocated. 423 */ 424 425#define DEFINE_EARLY_PER_CPU(_type, _name, _initvalue) \ 426 DEFINE_PER_CPU(_type, _name) = _initvalue; \ 427 __typeof__(_type) _name##_early_map[NR_CPUS] __initdata = \ 428 { [0 ... NR_CPUS-1] = _initvalue }; \ 429 __typeof__(_type) *_name##_early_ptr __refdata = _name##_early_map 430 431#define DEFINE_EARLY_PER_CPU_READ_MOSTLY(_type, _name, _initvalue) \ 432 DEFINE_PER_CPU_READ_MOSTLY(_type, _name) = _initvalue; \ 433 __typeof__(_type) _name##_early_map[NR_CPUS] __initdata = \ 434 { [0 ... NR_CPUS-1] = _initvalue }; \ 435 __typeof__(_type) *_name##_early_ptr __refdata = _name##_early_map 436 437#define EXPORT_EARLY_PER_CPU_SYMBOL(_name) \ 438 EXPORT_PER_CPU_SYMBOL(_name) 439 440#define DECLARE_EARLY_PER_CPU(_type, _name) \ 441 DECLARE_PER_CPU(_type, _name); \ 442 extern __typeof__(_type) *_name##_early_ptr; \ 443 extern __typeof__(_type) _name##_early_map[] 444 445#define DECLARE_EARLY_PER_CPU_READ_MOSTLY(_type, _name) \ 446 DECLARE_PER_CPU_READ_MOSTLY(_type, _name); \ 447 extern __typeof__(_type) *_name##_early_ptr; \ 448 extern __typeof__(_type) _name##_early_map[] 449 450#define early_per_cpu_ptr(_name) (_name##_early_ptr) 451#define early_per_cpu_map(_name, _idx) (_name##_early_map[_idx]) 452#define early_per_cpu(_name, _cpu) \ 453 *(early_per_cpu_ptr(_name) ? \ 454 &early_per_cpu_ptr(_name)[_cpu] : \ 455 &per_cpu(_name, _cpu)) 456 457#else /* !CONFIG_SMP */ 458#define DEFINE_EARLY_PER_CPU(_type, _name, _initvalue) \ 459 DEFINE_PER_CPU(_type, _name) = _initvalue 460 461#define DEFINE_EARLY_PER_CPU_READ_MOSTLY(_type, _name, _initvalue) \ 462 DEFINE_PER_CPU_READ_MOSTLY(_type, _name) = _initvalue 463 464#define EXPORT_EARLY_PER_CPU_SYMBOL(_name) \ 465 EXPORT_PER_CPU_SYMBOL(_name) 466 467#define DECLARE_EARLY_PER_CPU(_type, _name) \ 468 DECLARE_PER_CPU(_type, _name) 469 470#define DECLARE_EARLY_PER_CPU_READ_MOSTLY(_type, _name) \ 471 DECLARE_PER_CPU_READ_MOSTLY(_type, _name) 472 473#define early_per_cpu(_name, _cpu) per_cpu(_name, _cpu) 474#define early_per_cpu_ptr(_name) NULL 475/* no early_per_cpu_map() */ 476 477#endif /* !CONFIG_SMP */ 478 479#endif /* _ASM_X86_PERCPU_H */ 480