percpu.h 13 KB

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  1. #ifndef _ASM_X86_PERCPU_H
  2. #define _ASM_X86_PERCPU_H
  3. #ifdef CONFIG_X86_64
  4. #define __percpu_seg gs
  5. #define __percpu_mov_op movq
  6. #else
  7. #define __percpu_seg fs
  8. #define __percpu_mov_op movl
  9. #endif
  10. #ifdef __ASSEMBLY__
  11. /*
  12. * PER_CPU finds an address of a per-cpu variable.
  13. *
  14. * Args:
  15. * var - variable name
  16. * reg - 32bit register
  17. *
  18. * The resulting address is stored in the "reg" argument.
  19. *
  20. * Example:
  21. * PER_CPU(cpu_gdt_descr, %ebx)
  22. */
  23. #ifdef CONFIG_SMP
  24. #define PER_CPU(var, reg) \
  25. __percpu_mov_op %__percpu_seg:this_cpu_off, reg; \
  26. lea var(reg), reg
  27. #define PER_CPU_VAR(var) %__percpu_seg:var
  28. #else /* ! SMP */
  29. #define PER_CPU(var, reg) __percpu_mov_op $var, reg
  30. #define PER_CPU_VAR(var) var
  31. #endif /* SMP */
  32. #ifdef CONFIG_X86_64_SMP
  33. #define INIT_PER_CPU_VAR(var) init_per_cpu__##var
  34. #else
  35. #define INIT_PER_CPU_VAR(var) var
  36. #endif
  37. #else /* ...!ASSEMBLY */
  38. #include <linux/kernel.h>
  39. #include <linux/stringify.h>
  40. #ifdef CONFIG_SMP
  41. #define __percpu_arg(x) "%%"__stringify(__percpu_seg)":%P" #x
  42. #define __my_cpu_offset percpu_read(this_cpu_off)
  43. /*
  44. * Compared to the generic __my_cpu_offset version, the following
  45. * saves one instruction and avoids clobbering a temp register.
  46. */
  47. #define __this_cpu_ptr(ptr) \
  48. ({ \
  49. unsigned long tcp_ptr__; \
  50. __verify_pcpu_ptr(ptr); \
  51. asm volatile("add " __percpu_arg(1) ", %0" \
  52. : "=r" (tcp_ptr__) \
  53. : "m" (this_cpu_off), "0" (ptr)); \
  54. (typeof(*(ptr)) __kernel __force *)tcp_ptr__; \
  55. })
  56. #else
  57. #define __percpu_arg(x) "%P" #x
  58. #endif
  59. /*
  60. * Initialized pointers to per-cpu variables needed for the boot
  61. * processor need to use these macros to get the proper address
  62. * offset from __per_cpu_load on SMP.
  63. *
  64. * There also must be an entry in vmlinux_64.lds.S
  65. */
  66. #define DECLARE_INIT_PER_CPU(var) \
  67. extern typeof(var) init_per_cpu_var(var)
  68. #ifdef CONFIG_X86_64_SMP
  69. #define init_per_cpu_var(var) init_per_cpu__##var
  70. #else
  71. #define init_per_cpu_var(var) var
  72. #endif
  73. /* For arch-specific code, we can use direct single-insn ops (they
  74. * don't give an lvalue though). */
  75. extern void __bad_percpu_size(void);
  76. #define percpu_to_op(op, var, val) \
  77. do { \
  78. typedef typeof(var) pto_T__; \
  79. if (0) { \
  80. pto_T__ pto_tmp__; \
  81. pto_tmp__ = (val); \
  82. (void)pto_tmp__; \
  83. } \
  84. switch (sizeof(var)) { \
  85. case 1: \
  86. asm(op "b %1,"__percpu_arg(0) \
  87. : "+m" (var) \
  88. : "qi" ((pto_T__)(val))); \
  89. break; \
  90. case 2: \
  91. asm(op "w %1,"__percpu_arg(0) \
  92. : "+m" (var) \
  93. : "ri" ((pto_T__)(val))); \
  94. break; \
  95. case 4: \
  96. asm(op "l %1,"__percpu_arg(0) \
  97. : "+m" (var) \
  98. : "ri" ((pto_T__)(val))); \
  99. break; \
  100. case 8: \
  101. asm(op "q %1,"__percpu_arg(0) \
  102. : "+m" (var) \
  103. : "re" ((pto_T__)(val))); \
  104. break; \
  105. default: __bad_percpu_size(); \
  106. } \
  107. } while (0)
  108. /*
  109. * Generate a percpu add to memory instruction and optimize code
  110. * if one is added or subtracted.
  111. */
  112. #define percpu_add_op(var, val) \
  113. do { \
  114. typedef typeof(var) pao_T__; \
  115. const int pao_ID__ = (__builtin_constant_p(val) && \
  116. ((val) == 1 || (val) == -1)) ? (val) : 0; \
  117. if (0) { \
  118. pao_T__ pao_tmp__; \
  119. pao_tmp__ = (val); \
  120. (void)pao_tmp__; \
  121. } \
  122. switch (sizeof(var)) { \
  123. case 1: \
  124. if (pao_ID__ == 1) \
  125. asm("incb "__percpu_arg(0) : "+m" (var)); \
  126. else if (pao_ID__ == -1) \
  127. asm("decb "__percpu_arg(0) : "+m" (var)); \
  128. else \
  129. asm("addb %1, "__percpu_arg(0) \
  130. : "+m" (var) \
  131. : "qi" ((pao_T__)(val))); \
  132. break; \
  133. case 2: \
  134. if (pao_ID__ == 1) \
  135. asm("incw "__percpu_arg(0) : "+m" (var)); \
  136. else if (pao_ID__ == -1) \
  137. asm("decw "__percpu_arg(0) : "+m" (var)); \
  138. else \
  139. asm("addw %1, "__percpu_arg(0) \
  140. : "+m" (var) \
  141. : "ri" ((pao_T__)(val))); \
  142. break; \
  143. case 4: \
  144. if (pao_ID__ == 1) \
  145. asm("incl "__percpu_arg(0) : "+m" (var)); \
  146. else if (pao_ID__ == -1) \
  147. asm("decl "__percpu_arg(0) : "+m" (var)); \
  148. else \
  149. asm("addl %1, "__percpu_arg(0) \
  150. : "+m" (var) \
  151. : "ri" ((pao_T__)(val))); \
  152. break; \
  153. case 8: \
  154. if (pao_ID__ == 1) \
  155. asm("incq "__percpu_arg(0) : "+m" (var)); \
  156. else if (pao_ID__ == -1) \
  157. asm("decq "__percpu_arg(0) : "+m" (var)); \
  158. else \
  159. asm("addq %1, "__percpu_arg(0) \
  160. : "+m" (var) \
  161. : "re" ((pao_T__)(val))); \
  162. break; \
  163. default: __bad_percpu_size(); \
  164. } \
  165. } while (0)
  166. #define percpu_from_op(op, var, constraint) \
  167. ({ \
  168. typeof(var) pfo_ret__; \
  169. switch (sizeof(var)) { \
  170. case 1: \
  171. asm(op "b "__percpu_arg(1)",%0" \
  172. : "=q" (pfo_ret__) \
  173. : constraint); \
  174. break; \
  175. case 2: \
  176. asm(op "w "__percpu_arg(1)",%0" \
  177. : "=r" (pfo_ret__) \
  178. : constraint); \
  179. break; \
  180. case 4: \
  181. asm(op "l "__percpu_arg(1)",%0" \
  182. : "=r" (pfo_ret__) \
  183. : constraint); \
  184. break; \
  185. case 8: \
  186. asm(op "q "__percpu_arg(1)",%0" \
  187. : "=r" (pfo_ret__) \
  188. : constraint); \
  189. break; \
  190. default: __bad_percpu_size(); \
  191. } \
  192. pfo_ret__; \
  193. })
  194. #define percpu_unary_op(op, var) \
  195. ({ \
  196. switch (sizeof(var)) { \
  197. case 1: \
  198. asm(op "b "__percpu_arg(0) \
  199. : "+m" (var)); \
  200. break; \
  201. case 2: \
  202. asm(op "w "__percpu_arg(0) \
  203. : "+m" (var)); \
  204. break; \
  205. case 4: \
  206. asm(op "l "__percpu_arg(0) \
  207. : "+m" (var)); \
  208. break; \
  209. case 8: \
  210. asm(op "q "__percpu_arg(0) \
  211. : "+m" (var)); \
  212. break; \
  213. default: __bad_percpu_size(); \
  214. } \
  215. })
  216. /*
  217. * percpu_read() makes gcc load the percpu variable every time it is
  218. * accessed while percpu_read_stable() allows the value to be cached.
  219. * percpu_read_stable() is more efficient and can be used if its value
  220. * is guaranteed to be valid across cpus. The current users include
  221. * get_current() and get_thread_info() both of which are actually
  222. * per-thread variables implemented as per-cpu variables and thus
  223. * stable for the duration of the respective task.
  224. */
  225. #define percpu_read(var) percpu_from_op("mov", var, "m" (var))
  226. #define percpu_read_stable(var) percpu_from_op("mov", var, "p" (&(var)))
  227. #define percpu_write(var, val) percpu_to_op("mov", var, val)
  228. #define percpu_add(var, val) percpu_add_op(var, val)
  229. #define percpu_sub(var, val) percpu_add_op(var, -(val))
  230. #define percpu_and(var, val) percpu_to_op("and", var, val)
  231. #define percpu_or(var, val) percpu_to_op("or", var, val)
  232. #define percpu_xor(var, val) percpu_to_op("xor", var, val)
  233. #define percpu_inc(var) percpu_unary_op("inc", var)
  234. #define __this_cpu_read_1(pcp) percpu_from_op("mov", (pcp), "m"(pcp))
  235. #define __this_cpu_read_2(pcp) percpu_from_op("mov", (pcp), "m"(pcp))
  236. #define __this_cpu_read_4(pcp) percpu_from_op("mov", (pcp), "m"(pcp))
  237. #define __this_cpu_write_1(pcp, val) percpu_to_op("mov", (pcp), val)
  238. #define __this_cpu_write_2(pcp, val) percpu_to_op("mov", (pcp), val)
  239. #define __this_cpu_write_4(pcp, val) percpu_to_op("mov", (pcp), val)
  240. #define __this_cpu_add_1(pcp, val) percpu_add_op((pcp), val)
  241. #define __this_cpu_add_2(pcp, val) percpu_add_op((pcp), val)
  242. #define __this_cpu_add_4(pcp, val) percpu_add_op((pcp), val)
  243. #define __this_cpu_and_1(pcp, val) percpu_to_op("and", (pcp), val)
  244. #define __this_cpu_and_2(pcp, val) percpu_to_op("and", (pcp), val)
  245. #define __this_cpu_and_4(pcp, val) percpu_to_op("and", (pcp), val)
  246. #define __this_cpu_or_1(pcp, val) percpu_to_op("or", (pcp), val)
  247. #define __this_cpu_or_2(pcp, val) percpu_to_op("or", (pcp), val)
  248. #define __this_cpu_or_4(pcp, val) percpu_to_op("or", (pcp), val)
  249. #define __this_cpu_xor_1(pcp, val) percpu_to_op("xor", (pcp), val)
  250. #define __this_cpu_xor_2(pcp, val) percpu_to_op("xor", (pcp), val)
  251. #define __this_cpu_xor_4(pcp, val) percpu_to_op("xor", (pcp), val)
  252. #define this_cpu_read_1(pcp) percpu_from_op("mov", (pcp), "m"(pcp))
  253. #define this_cpu_read_2(pcp) percpu_from_op("mov", (pcp), "m"(pcp))
  254. #define this_cpu_read_4(pcp) percpu_from_op("mov", (pcp), "m"(pcp))
  255. #define this_cpu_write_1(pcp, val) percpu_to_op("mov", (pcp), val)
  256. #define this_cpu_write_2(pcp, val) percpu_to_op("mov", (pcp), val)
  257. #define this_cpu_write_4(pcp, val) percpu_to_op("mov", (pcp), val)
  258. #define this_cpu_add_1(pcp, val) percpu_add_op((pcp), val)
  259. #define this_cpu_add_2(pcp, val) percpu_add_op((pcp), val)
  260. #define this_cpu_add_4(pcp, val) percpu_add_op((pcp), val)
  261. #define this_cpu_and_1(pcp, val) percpu_to_op("and", (pcp), val)
  262. #define this_cpu_and_2(pcp, val) percpu_to_op("and", (pcp), val)
  263. #define this_cpu_and_4(pcp, val) percpu_to_op("and", (pcp), val)
  264. #define this_cpu_or_1(pcp, val) percpu_to_op("or", (pcp), val)
  265. #define this_cpu_or_2(pcp, val) percpu_to_op("or", (pcp), val)
  266. #define this_cpu_or_4(pcp, val) percpu_to_op("or", (pcp), val)
  267. #define this_cpu_xor_1(pcp, val) percpu_to_op("xor", (pcp), val)
  268. #define this_cpu_xor_2(pcp, val) percpu_to_op("xor", (pcp), val)
  269. #define this_cpu_xor_4(pcp, val) percpu_to_op("xor", (pcp), val)
  270. #define irqsafe_cpu_add_1(pcp, val) percpu_add_op((pcp), val)
  271. #define irqsafe_cpu_add_2(pcp, val) percpu_add_op((pcp), val)
  272. #define irqsafe_cpu_add_4(pcp, val) percpu_add_op((pcp), val)
  273. #define irqsafe_cpu_and_1(pcp, val) percpu_to_op("and", (pcp), val)
  274. #define irqsafe_cpu_and_2(pcp, val) percpu_to_op("and", (pcp), val)
  275. #define irqsafe_cpu_and_4(pcp, val) percpu_to_op("and", (pcp), val)
  276. #define irqsafe_cpu_or_1(pcp, val) percpu_to_op("or", (pcp), val)
  277. #define irqsafe_cpu_or_2(pcp, val) percpu_to_op("or", (pcp), val)
  278. #define irqsafe_cpu_or_4(pcp, val) percpu_to_op("or", (pcp), val)
  279. #define irqsafe_cpu_xor_1(pcp, val) percpu_to_op("xor", (pcp), val)
  280. #define irqsafe_cpu_xor_2(pcp, val) percpu_to_op("xor", (pcp), val)
  281. #define irqsafe_cpu_xor_4(pcp, val) percpu_to_op("xor", (pcp), val)
  282. /*
  283. * Per cpu atomic 64 bit operations are only available under 64 bit.
  284. * 32 bit must fall back to generic operations.
  285. */
  286. #ifdef CONFIG_X86_64
  287. #define __this_cpu_read_8(pcp) percpu_from_op("mov", (pcp), "m"(pcp))
  288. #define __this_cpu_write_8(pcp, val) percpu_to_op("mov", (pcp), val)
  289. #define __this_cpu_add_8(pcp, val) percpu_add_op((pcp), val)
  290. #define __this_cpu_and_8(pcp, val) percpu_to_op("and", (pcp), val)
  291. #define __this_cpu_or_8(pcp, val) percpu_to_op("or", (pcp), val)
  292. #define __this_cpu_xor_8(pcp, val) percpu_to_op("xor", (pcp), val)
  293. #define this_cpu_read_8(pcp) percpu_from_op("mov", (pcp), "m"(pcp))
  294. #define this_cpu_write_8(pcp, val) percpu_to_op("mov", (pcp), val)
  295. #define this_cpu_add_8(pcp, val) percpu_add_op((pcp), val)
  296. #define this_cpu_and_8(pcp, val) percpu_to_op("and", (pcp), val)
  297. #define this_cpu_or_8(pcp, val) percpu_to_op("or", (pcp), val)
  298. #define this_cpu_xor_8(pcp, val) percpu_to_op("xor", (pcp), val)
  299. #define irqsafe_cpu_add_8(pcp, val) percpu_add_op((pcp), val)
  300. #define irqsafe_cpu_and_8(pcp, val) percpu_to_op("and", (pcp), val)
  301. #define irqsafe_cpu_or_8(pcp, val) percpu_to_op("or", (pcp), val)
  302. #define irqsafe_cpu_xor_8(pcp, val) percpu_to_op("xor", (pcp), val)
  303. #endif
  304. /* This is not atomic against other CPUs -- CPU preemption needs to be off */
  305. #define x86_test_and_clear_bit_percpu(bit, var) \
  306. ({ \
  307. int old__; \
  308. asm volatile("btr %2,"__percpu_arg(1)"\n\tsbbl %0,%0" \
  309. : "=r" (old__), "+m" (var) \
  310. : "dIr" (bit)); \
  311. old__; \
  312. })
  313. #include <asm-generic/percpu.h>
  314. /* We can use this directly for local CPU (faster). */
  315. DECLARE_PER_CPU(unsigned long, this_cpu_off);
  316. #endif /* !__ASSEMBLY__ */
  317. #ifdef CONFIG_SMP
  318. /*
  319. * Define the "EARLY_PER_CPU" macros. These are used for some per_cpu
  320. * variables that are initialized and accessed before there are per_cpu
  321. * areas allocated.
  322. */
  323. #define DEFINE_EARLY_PER_CPU(_type, _name, _initvalue) \
  324. DEFINE_PER_CPU(_type, _name) = _initvalue; \
  325. __typeof__(_type) _name##_early_map[NR_CPUS] __initdata = \
  326. { [0 ... NR_CPUS-1] = _initvalue }; \
  327. __typeof__(_type) *_name##_early_ptr __refdata = _name##_early_map
  328. #define EXPORT_EARLY_PER_CPU_SYMBOL(_name) \
  329. EXPORT_PER_CPU_SYMBOL(_name)
  330. #define DECLARE_EARLY_PER_CPU(_type, _name) \
  331. DECLARE_PER_CPU(_type, _name); \
  332. extern __typeof__(_type) *_name##_early_ptr; \
  333. extern __typeof__(_type) _name##_early_map[]
  334. #define early_per_cpu_ptr(_name) (_name##_early_ptr)
  335. #define early_per_cpu_map(_name, _idx) (_name##_early_map[_idx])
  336. #define early_per_cpu(_name, _cpu) \
  337. *(early_per_cpu_ptr(_name) ? \
  338. &early_per_cpu_ptr(_name)[_cpu] : \
  339. &per_cpu(_name, _cpu))
  340. #else /* !CONFIG_SMP */
  341. #define DEFINE_EARLY_PER_CPU(_type, _name, _initvalue) \
  342. DEFINE_PER_CPU(_type, _name) = _initvalue
  343. #define EXPORT_EARLY_PER_CPU_SYMBOL(_name) \
  344. EXPORT_PER_CPU_SYMBOL(_name)
  345. #define DECLARE_EARLY_PER_CPU(_type, _name) \
  346. DECLARE_PER_CPU(_type, _name)
  347. #define early_per_cpu(_name, _cpu) per_cpu(_name, _cpu)
  348. #define early_per_cpu_ptr(_name) NULL
  349. /* no early_per_cpu_map() */
  350. #endif /* !CONFIG_SMP */
  351. #endif /* _ASM_X86_PERCPU_H */