1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * Copyright (c) 2022 Meta Platforms, Inc. and affiliates. 4 * Copyright (c) 2022 Tejun Heo <tj@kernel.org> 5 * Copyright (c) 2022 David Vernet <dvernet@meta.com> 6 */ 7 #ifndef __SCX_COMMON_BPF_H 8 #define __SCX_COMMON_BPF_H 9 10 /* 11 * The generated kfunc prototypes in vmlinux.h are missing address space 12 * attributes which cause build failures. For now, suppress the generated 13 * prototypes. See https://github.com/sched-ext/scx/issues/1111. 14 */ 15 #define BPF_NO_KFUNC_PROTOTYPES 16 17 #ifdef LSP 18 #define __bpf__ 19 #include "../vmlinux.h" 20 #else 21 #include "vmlinux.h" 22 #endif 23 24 #include <bpf/bpf_helpers.h> 25 #include <bpf/bpf_tracing.h> 26 #include <asm-generic/errno.h> 27 #include "user_exit_info.h" 28 #include "enum_defs.autogen.h" 29 30 #define PF_WQ_WORKER 0x00000020 /* I'm a workqueue worker */ 31 #define PF_KTHREAD 0x00200000 /* I am a kernel thread */ 32 #define PF_EXITING 0x00000004 33 #define CLOCK_MONOTONIC 1 34 35 extern int LINUX_KERNEL_VERSION __kconfig; 36 extern const char CONFIG_CC_VERSION_TEXT[64] __kconfig __weak; 37 extern const char CONFIG_LOCALVERSION[64] __kconfig __weak; 38 39 /* 40 * Earlier versions of clang/pahole lost upper 32bits in 64bit enums which can 41 * lead to really confusing misbehaviors. Let's trigger a build failure. 42 */ 43 static inline void ___vmlinux_h_sanity_check___(void) 44 { 45 _Static_assert(SCX_DSQ_FLAG_BUILTIN, 46 "bpftool generated vmlinux.h is missing high bits for 64bit enums, upgrade clang and pahole"); 47 } 48 49 s32 scx_bpf_create_dsq(u64 dsq_id, s32 node) __ksym; 50 s32 scx_bpf_select_cpu_dfl(struct task_struct *p, s32 prev_cpu, u64 wake_flags, bool *is_idle) __ksym; 51 s32 scx_bpf_select_cpu_and(struct task_struct *p, s32 prev_cpu, u64 wake_flags, 52 const struct cpumask *cpus_allowed, u64 flags) __ksym __weak; 53 void scx_bpf_dsq_insert(struct task_struct *p, u64 dsq_id, u64 slice, u64 enq_flags) __ksym __weak; 54 void scx_bpf_dsq_insert_vtime(struct task_struct *p, u64 dsq_id, u64 slice, u64 vtime, u64 enq_flags) __ksym __weak; 55 u32 scx_bpf_dispatch_nr_slots(void) __ksym; 56 void scx_bpf_dispatch_cancel(void) __ksym; 57 bool scx_bpf_dsq_move_to_local(u64 dsq_id) __ksym __weak; 58 void scx_bpf_dsq_move_set_slice(struct bpf_iter_scx_dsq *it__iter, u64 slice) __ksym __weak; 59 void scx_bpf_dsq_move_set_vtime(struct bpf_iter_scx_dsq *it__iter, u64 vtime) __ksym __weak; 60 bool scx_bpf_dsq_move(struct bpf_iter_scx_dsq *it__iter, struct task_struct *p, u64 dsq_id, u64 enq_flags) __ksym __weak; 61 bool scx_bpf_dsq_move_vtime(struct bpf_iter_scx_dsq *it__iter, struct task_struct *p, u64 dsq_id, u64 enq_flags) __ksym __weak; 62 u32 scx_bpf_reenqueue_local(void) __ksym; 63 void scx_bpf_kick_cpu(s32 cpu, u64 flags) __ksym; 64 s32 scx_bpf_dsq_nr_queued(u64 dsq_id) __ksym; 65 void scx_bpf_destroy_dsq(u64 dsq_id) __ksym; 66 int bpf_iter_scx_dsq_new(struct bpf_iter_scx_dsq *it, u64 dsq_id, u64 flags) __ksym __weak; 67 struct task_struct *bpf_iter_scx_dsq_next(struct bpf_iter_scx_dsq *it) __ksym __weak; 68 void bpf_iter_scx_dsq_destroy(struct bpf_iter_scx_dsq *it) __ksym __weak; 69 void scx_bpf_exit_bstr(s64 exit_code, char *fmt, unsigned long long *data, u32 data__sz) __ksym __weak; 70 void scx_bpf_error_bstr(char *fmt, unsigned long long *data, u32 data_len) __ksym; 71 void scx_bpf_dump_bstr(char *fmt, unsigned long long *data, u32 data_len) __ksym __weak; 72 u32 scx_bpf_cpuperf_cap(s32 cpu) __ksym __weak; 73 u32 scx_bpf_cpuperf_cur(s32 cpu) __ksym __weak; 74 void scx_bpf_cpuperf_set(s32 cpu, u32 perf) __ksym __weak; 75 u32 scx_bpf_nr_node_ids(void) __ksym __weak; 76 u32 scx_bpf_nr_cpu_ids(void) __ksym __weak; 77 int scx_bpf_cpu_node(s32 cpu) __ksym __weak; 78 const struct cpumask *scx_bpf_get_possible_cpumask(void) __ksym __weak; 79 const struct cpumask *scx_bpf_get_online_cpumask(void) __ksym __weak; 80 void scx_bpf_put_cpumask(const struct cpumask *cpumask) __ksym __weak; 81 const struct cpumask *scx_bpf_get_idle_cpumask_node(int node) __ksym __weak; 82 const struct cpumask *scx_bpf_get_idle_cpumask(void) __ksym; 83 const struct cpumask *scx_bpf_get_idle_smtmask_node(int node) __ksym __weak; 84 const struct cpumask *scx_bpf_get_idle_smtmask(void) __ksym; 85 void scx_bpf_put_idle_cpumask(const struct cpumask *cpumask) __ksym; 86 bool scx_bpf_test_and_clear_cpu_idle(s32 cpu) __ksym; 87 s32 scx_bpf_pick_idle_cpu_node(const cpumask_t *cpus_allowed, int node, u64 flags) __ksym __weak; 88 s32 scx_bpf_pick_idle_cpu(const cpumask_t *cpus_allowed, u64 flags) __ksym; 89 s32 scx_bpf_pick_any_cpu_node(const cpumask_t *cpus_allowed, int node, u64 flags) __ksym __weak; 90 s32 scx_bpf_pick_any_cpu(const cpumask_t *cpus_allowed, u64 flags) __ksym; 91 bool scx_bpf_task_running(const struct task_struct *p) __ksym; 92 s32 scx_bpf_task_cpu(const struct task_struct *p) __ksym; 93 struct rq *scx_bpf_cpu_rq(s32 cpu) __ksym; 94 struct cgroup *scx_bpf_task_cgroup(struct task_struct *p) __ksym __weak; 95 u64 scx_bpf_now(void) __ksym __weak; 96 void scx_bpf_events(struct scx_event_stats *events, size_t events__sz) __ksym __weak; 97 98 /* 99 * Use the following as @it__iter when calling scx_bpf_dsq_move[_vtime]() from 100 * within bpf_for_each() loops. 101 */ 102 #define BPF_FOR_EACH_ITER (&___it) 103 104 #define scx_read_event(e, name) \ 105 (bpf_core_field_exists((e)->name) ? (e)->name : 0) 106 107 static inline __attribute__((format(printf, 1, 2))) 108 void ___scx_bpf_bstr_format_checker(const char *fmt, ...) {} 109 110 /* 111 * Helper macro for initializing the fmt and variadic argument inputs to both 112 * bstr exit kfuncs. Callers to this function should use ___fmt and ___param to 113 * refer to the initialized list of inputs to the bstr kfunc. 114 */ 115 #define scx_bpf_bstr_preamble(fmt, args...) \ 116 static char ___fmt[] = fmt; \ 117 /* \ 118 * Note that __param[] must have at least one \ 119 * element to keep the verifier happy. \ 120 */ \ 121 unsigned long long ___param[___bpf_narg(args) ?: 1] = {}; \ 122 \ 123 _Pragma("GCC diagnostic push") \ 124 _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \ 125 ___bpf_fill(___param, args); \ 126 _Pragma("GCC diagnostic pop") 127 128 /* 129 * scx_bpf_exit() wraps the scx_bpf_exit_bstr() kfunc with variadic arguments 130 * instead of an array of u64. Using this macro will cause the scheduler to 131 * exit cleanly with the specified exit code being passed to user space. 132 */ 133 #define scx_bpf_exit(code, fmt, args...) \ 134 ({ \ 135 scx_bpf_bstr_preamble(fmt, args) \ 136 scx_bpf_exit_bstr(code, ___fmt, ___param, sizeof(___param)); \ 137 ___scx_bpf_bstr_format_checker(fmt, ##args); \ 138 }) 139 140 /* 141 * scx_bpf_error() wraps the scx_bpf_error_bstr() kfunc with variadic arguments 142 * instead of an array of u64. Invoking this macro will cause the scheduler to 143 * exit in an erroneous state, with diagnostic information being passed to the 144 * user. 145 */ 146 #define scx_bpf_error(fmt, args...) \ 147 ({ \ 148 scx_bpf_bstr_preamble(fmt, args) \ 149 scx_bpf_error_bstr(___fmt, ___param, sizeof(___param)); \ 150 ___scx_bpf_bstr_format_checker(fmt, ##args); \ 151 }) 152 153 /* 154 * scx_bpf_dump() wraps the scx_bpf_dump_bstr() kfunc with variadic arguments 155 * instead of an array of u64. To be used from ops.dump() and friends. 156 */ 157 #define scx_bpf_dump(fmt, args...) \ 158 ({ \ 159 scx_bpf_bstr_preamble(fmt, args) \ 160 scx_bpf_dump_bstr(___fmt, ___param, sizeof(___param)); \ 161 ___scx_bpf_bstr_format_checker(fmt, ##args); \ 162 }) 163 164 /* 165 * scx_bpf_dump_header() is a wrapper around scx_bpf_dump that adds a header 166 * of system information for debugging. 167 */ 168 #define scx_bpf_dump_header() \ 169 ({ \ 170 scx_bpf_dump("kernel: %d.%d.%d %s\ncc: %s\n", \ 171 LINUX_KERNEL_VERSION >> 16, \ 172 LINUX_KERNEL_VERSION >> 8 & 0xFF, \ 173 LINUX_KERNEL_VERSION & 0xFF, \ 174 CONFIG_LOCALVERSION, \ 175 CONFIG_CC_VERSION_TEXT); \ 176 }) 177 178 #define BPF_STRUCT_OPS(name, args...) \ 179 SEC("struct_ops/"#name) \ 180 BPF_PROG(name, ##args) 181 182 #define BPF_STRUCT_OPS_SLEEPABLE(name, args...) \ 183 SEC("struct_ops.s/"#name) \ 184 BPF_PROG(name, ##args) 185 186 /** 187 * RESIZABLE_ARRAY - Generates annotations for an array that may be resized 188 * @elfsec: the data section of the BPF program in which to place the array 189 * @arr: the name of the array 190 * 191 * libbpf has an API for setting map value sizes. Since data sections (i.e. 192 * bss, data, rodata) themselves are maps, a data section can be resized. If 193 * a data section has an array as its last element, the BTF info for that 194 * array will be adjusted so that length of the array is extended to meet the 195 * new length of the data section. This macro annotates an array to have an 196 * element count of one with the assumption that this array can be resized 197 * within the userspace program. It also annotates the section specifier so 198 * this array exists in a custom sub data section which can be resized 199 * independently. 200 * 201 * See RESIZE_ARRAY() for the userspace convenience macro for resizing an 202 * array declared with RESIZABLE_ARRAY(). 203 */ 204 #define RESIZABLE_ARRAY(elfsec, arr) arr[1] SEC("."#elfsec"."#arr) 205 206 /** 207 * MEMBER_VPTR - Obtain the verified pointer to a struct or array member 208 * @base: struct or array to index 209 * @member: dereferenced member (e.g. .field, [idx0][idx1], .field[idx0] ...) 210 * 211 * The verifier often gets confused by the instruction sequence the compiler 212 * generates for indexing struct fields or arrays. This macro forces the 213 * compiler to generate a code sequence which first calculates the byte offset, 214 * checks it against the struct or array size and add that byte offset to 215 * generate the pointer to the member to help the verifier. 216 * 217 * Ideally, we want to abort if the calculated offset is out-of-bounds. However, 218 * BPF currently doesn't support abort, so evaluate to %NULL instead. The caller 219 * must check for %NULL and take appropriate action to appease the verifier. To 220 * avoid confusing the verifier, it's best to check for %NULL and dereference 221 * immediately. 222 * 223 * vptr = MEMBER_VPTR(my_array, [i][j]); 224 * if (!vptr) 225 * return error; 226 * *vptr = new_value; 227 * 228 * sizeof(@base) should encompass the memory area to be accessed and thus can't 229 * be a pointer to the area. Use `MEMBER_VPTR(*ptr, .member)` instead of 230 * `MEMBER_VPTR(ptr, ->member)`. 231 */ 232 #define MEMBER_VPTR(base, member) (typeof((base) member) *) \ 233 ({ \ 234 u64 __base = (u64)&(base); \ 235 u64 __addr = (u64)&((base) member) - __base; \ 236 _Static_assert(sizeof(base) >= sizeof((base) member), \ 237 "@base is smaller than @member, is @base a pointer?"); \ 238 asm volatile ( \ 239 "if %0 <= %[max] goto +2\n" \ 240 "%0 = 0\n" \ 241 "goto +1\n" \ 242 "%0 += %1\n" \ 243 : "+r"(__addr) \ 244 : "r"(__base), \ 245 [max]"i"(sizeof(base) - sizeof((base) member))); \ 246 __addr; \ 247 }) 248 249 /** 250 * ARRAY_ELEM_PTR - Obtain the verified pointer to an array element 251 * @arr: array to index into 252 * @i: array index 253 * @n: number of elements in array 254 * 255 * Similar to MEMBER_VPTR() but is intended for use with arrays where the 256 * element count needs to be explicit. 257 * It can be used in cases where a global array is defined with an initial 258 * size but is intended to be be resized before loading the BPF program. 259 * Without this version of the macro, MEMBER_VPTR() will use the compile time 260 * size of the array to compute the max, which will result in rejection by 261 * the verifier. 262 */ 263 #define ARRAY_ELEM_PTR(arr, i, n) (typeof(arr[i]) *) \ 264 ({ \ 265 u64 __base = (u64)arr; \ 266 u64 __addr = (u64)&(arr[i]) - __base; \ 267 asm volatile ( \ 268 "if %0 <= %[max] goto +2\n" \ 269 "%0 = 0\n" \ 270 "goto +1\n" \ 271 "%0 += %1\n" \ 272 : "+r"(__addr) \ 273 : "r"(__base), \ 274 [max]"r"(sizeof(arr[0]) * ((n) - 1))); \ 275 __addr; \ 276 }) 277 278 279 /* 280 * BPF declarations and helpers 281 */ 282 283 /* list and rbtree */ 284 #define __contains(name, node) __attribute__((btf_decl_tag("contains:" #name ":" #node))) 285 #define private(name) SEC(".data." #name) __hidden __attribute__((aligned(8))) 286 287 void *bpf_obj_new_impl(__u64 local_type_id, void *meta) __ksym; 288 void bpf_obj_drop_impl(void *kptr, void *meta) __ksym; 289 290 #define bpf_obj_new(type) ((type *)bpf_obj_new_impl(bpf_core_type_id_local(type), NULL)) 291 #define bpf_obj_drop(kptr) bpf_obj_drop_impl(kptr, NULL) 292 293 int bpf_list_push_front_impl(struct bpf_list_head *head, 294 struct bpf_list_node *node, 295 void *meta, __u64 off) __ksym; 296 #define bpf_list_push_front(head, node) bpf_list_push_front_impl(head, node, NULL, 0) 297 298 int bpf_list_push_back_impl(struct bpf_list_head *head, 299 struct bpf_list_node *node, 300 void *meta, __u64 off) __ksym; 301 #define bpf_list_push_back(head, node) bpf_list_push_back_impl(head, node, NULL, 0) 302 303 struct bpf_list_node *bpf_list_pop_front(struct bpf_list_head *head) __ksym; 304 struct bpf_list_node *bpf_list_pop_back(struct bpf_list_head *head) __ksym; 305 struct bpf_rb_node *bpf_rbtree_remove(struct bpf_rb_root *root, 306 struct bpf_rb_node *node) __ksym; 307 int bpf_rbtree_add_impl(struct bpf_rb_root *root, struct bpf_rb_node *node, 308 bool (less)(struct bpf_rb_node *a, const struct bpf_rb_node *b), 309 void *meta, __u64 off) __ksym; 310 #define bpf_rbtree_add(head, node, less) bpf_rbtree_add_impl(head, node, less, NULL, 0) 311 312 struct bpf_rb_node *bpf_rbtree_first(struct bpf_rb_root *root) __ksym; 313 314 void *bpf_refcount_acquire_impl(void *kptr, void *meta) __ksym; 315 #define bpf_refcount_acquire(kptr) bpf_refcount_acquire_impl(kptr, NULL) 316 317 /* task */ 318 struct task_struct *bpf_task_from_pid(s32 pid) __ksym; 319 struct task_struct *bpf_task_acquire(struct task_struct *p) __ksym; 320 void bpf_task_release(struct task_struct *p) __ksym; 321 322 /* cgroup */ 323 struct cgroup *bpf_cgroup_ancestor(struct cgroup *cgrp, int level) __ksym; 324 void bpf_cgroup_release(struct cgroup *cgrp) __ksym; 325 struct cgroup *bpf_cgroup_from_id(u64 cgid) __ksym; 326 327 /* css iteration */ 328 struct bpf_iter_css; 329 struct cgroup_subsys_state; 330 extern int bpf_iter_css_new(struct bpf_iter_css *it, 331 struct cgroup_subsys_state *start, 332 unsigned int flags) __weak __ksym; 333 extern struct cgroup_subsys_state * 334 bpf_iter_css_next(struct bpf_iter_css *it) __weak __ksym; 335 extern void bpf_iter_css_destroy(struct bpf_iter_css *it) __weak __ksym; 336 337 /* cpumask */ 338 struct bpf_cpumask *bpf_cpumask_create(void) __ksym; 339 struct bpf_cpumask *bpf_cpumask_acquire(struct bpf_cpumask *cpumask) __ksym; 340 void bpf_cpumask_release(struct bpf_cpumask *cpumask) __ksym; 341 u32 bpf_cpumask_first(const struct cpumask *cpumask) __ksym; 342 u32 bpf_cpumask_first_zero(const struct cpumask *cpumask) __ksym; 343 void bpf_cpumask_set_cpu(u32 cpu, struct bpf_cpumask *cpumask) __ksym; 344 void bpf_cpumask_clear_cpu(u32 cpu, struct bpf_cpumask *cpumask) __ksym; 345 bool bpf_cpumask_test_cpu(u32 cpu, const struct cpumask *cpumask) __ksym; 346 bool bpf_cpumask_test_and_set_cpu(u32 cpu, struct bpf_cpumask *cpumask) __ksym; 347 bool bpf_cpumask_test_and_clear_cpu(u32 cpu, struct bpf_cpumask *cpumask) __ksym; 348 void bpf_cpumask_setall(struct bpf_cpumask *cpumask) __ksym; 349 void bpf_cpumask_clear(struct bpf_cpumask *cpumask) __ksym; 350 bool bpf_cpumask_and(struct bpf_cpumask *dst, const struct cpumask *src1, 351 const struct cpumask *src2) __ksym; 352 void bpf_cpumask_or(struct bpf_cpumask *dst, const struct cpumask *src1, 353 const struct cpumask *src2) __ksym; 354 void bpf_cpumask_xor(struct bpf_cpumask *dst, const struct cpumask *src1, 355 const struct cpumask *src2) __ksym; 356 bool bpf_cpumask_equal(const struct cpumask *src1, const struct cpumask *src2) __ksym; 357 bool bpf_cpumask_intersects(const struct cpumask *src1, const struct cpumask *src2) __ksym; 358 bool bpf_cpumask_subset(const struct cpumask *src1, const struct cpumask *src2) __ksym; 359 bool bpf_cpumask_empty(const struct cpumask *cpumask) __ksym; 360 bool bpf_cpumask_full(const struct cpumask *cpumask) __ksym; 361 void bpf_cpumask_copy(struct bpf_cpumask *dst, const struct cpumask *src) __ksym; 362 u32 bpf_cpumask_any_distribute(const struct cpumask *cpumask) __ksym; 363 u32 bpf_cpumask_any_and_distribute(const struct cpumask *src1, 364 const struct cpumask *src2) __ksym; 365 u32 bpf_cpumask_weight(const struct cpumask *cpumask) __ksym; 366 367 int bpf_iter_bits_new(struct bpf_iter_bits *it, const u64 *unsafe_ptr__ign, u32 nr_words) __ksym; 368 int *bpf_iter_bits_next(struct bpf_iter_bits *it) __ksym; 369 void bpf_iter_bits_destroy(struct bpf_iter_bits *it) __ksym; 370 371 #define def_iter_struct(name) \ 372 struct bpf_iter_##name { \ 373 struct bpf_iter_bits it; \ 374 const struct cpumask *bitmap; \ 375 }; 376 377 #define def_iter_new(name) \ 378 static inline int bpf_iter_##name##_new( \ 379 struct bpf_iter_##name *it, const u64 *unsafe_ptr__ign, u32 nr_words) \ 380 { \ 381 it->bitmap = scx_bpf_get_##name##_cpumask(); \ 382 return bpf_iter_bits_new(&it->it, (const u64 *)it->bitmap, \ 383 sizeof(struct cpumask) / 8); \ 384 } 385 386 #define def_iter_next(name) \ 387 static inline int *bpf_iter_##name##_next(struct bpf_iter_##name *it) { \ 388 return bpf_iter_bits_next(&it->it); \ 389 } 390 391 #define def_iter_destroy(name) \ 392 static inline void bpf_iter_##name##_destroy(struct bpf_iter_##name *it) { \ 393 scx_bpf_put_cpumask(it->bitmap); \ 394 bpf_iter_bits_destroy(&it->it); \ 395 } 396 #define def_for_each_cpu(cpu, name) for_each_##name##_cpu(cpu) 397 398 /// Provides iterator for possible and online cpus. 399 /// 400 /// # Example 401 /// 402 /// ``` 403 /// static inline void example_use() { 404 /// int *cpu; 405 /// 406 /// for_each_possible_cpu(cpu){ 407 /// bpf_printk("CPU %d is possible", *cpu); 408 /// } 409 /// 410 /// for_each_online_cpu(cpu){ 411 /// bpf_printk("CPU %d is online", *cpu); 412 /// } 413 /// } 414 /// ``` 415 def_iter_struct(possible); 416 def_iter_new(possible); 417 def_iter_next(possible); 418 def_iter_destroy(possible); 419 #define for_each_possible_cpu(cpu) bpf_for_each(possible, cpu, NULL, 0) 420 421 def_iter_struct(online); 422 def_iter_new(online); 423 def_iter_next(online); 424 def_iter_destroy(online); 425 #define for_each_online_cpu(cpu) bpf_for_each(online, cpu, NULL, 0) 426 427 /* 428 * Access a cpumask in read-only mode (typically to check bits). 429 */ 430 static __always_inline const struct cpumask *cast_mask(struct bpf_cpumask *mask) 431 { 432 return (const struct cpumask *)mask; 433 } 434 435 /* 436 * Return true if task @p cannot migrate to a different CPU, false 437 * otherwise. 438 */ 439 static inline bool is_migration_disabled(const struct task_struct *p) 440 { 441 if (bpf_core_field_exists(p->migration_disabled)) 442 return p->migration_disabled; 443 return false; 444 } 445 446 /* rcu */ 447 void bpf_rcu_read_lock(void) __ksym; 448 void bpf_rcu_read_unlock(void) __ksym; 449 450 /* 451 * Time helpers, most of which are from jiffies.h. 452 */ 453 454 /** 455 * time_delta - Calculate the delta between new and old time stamp 456 * @after: first comparable as u64 457 * @before: second comparable as u64 458 * 459 * Return: the time difference, which is >= 0 460 */ 461 static inline s64 time_delta(u64 after, u64 before) 462 { 463 return (s64)(after - before) > 0 ? (s64)(after - before) : 0; 464 } 465 466 /** 467 * time_after - returns true if the time a is after time b. 468 * @a: first comparable as u64 469 * @b: second comparable as u64 470 * 471 * Do this with "<0" and ">=0" to only test the sign of the result. A 472 * good compiler would generate better code (and a really good compiler 473 * wouldn't care). Gcc is currently neither. 474 * 475 * Return: %true is time a is after time b, otherwise %false. 476 */ 477 static inline bool time_after(u64 a, u64 b) 478 { 479 return (s64)(b - a) < 0; 480 } 481 482 /** 483 * time_before - returns true if the time a is before time b. 484 * @a: first comparable as u64 485 * @b: second comparable as u64 486 * 487 * Return: %true is time a is before time b, otherwise %false. 488 */ 489 static inline bool time_before(u64 a, u64 b) 490 { 491 return time_after(b, a); 492 } 493 494 /** 495 * time_after_eq - returns true if the time a is after or the same as time b. 496 * @a: first comparable as u64 497 * @b: second comparable as u64 498 * 499 * Return: %true is time a is after or the same as time b, otherwise %false. 500 */ 501 static inline bool time_after_eq(u64 a, u64 b) 502 { 503 return (s64)(a - b) >= 0; 504 } 505 506 /** 507 * time_before_eq - returns true if the time a is before or the same as time b. 508 * @a: first comparable as u64 509 * @b: second comparable as u64 510 * 511 * Return: %true is time a is before or the same as time b, otherwise %false. 512 */ 513 static inline bool time_before_eq(u64 a, u64 b) 514 { 515 return time_after_eq(b, a); 516 } 517 518 /** 519 * time_in_range - Calculate whether a is in the range of [b, c]. 520 * @a: time to test 521 * @b: beginning of the range 522 * @c: end of the range 523 * 524 * Return: %true is time a is in the range [b, c], otherwise %false. 525 */ 526 static inline bool time_in_range(u64 a, u64 b, u64 c) 527 { 528 return time_after_eq(a, b) && time_before_eq(a, c); 529 } 530 531 /** 532 * time_in_range_open - Calculate whether a is in the range of [b, c). 533 * @a: time to test 534 * @b: beginning of the range 535 * @c: end of the range 536 * 537 * Return: %true is time a is in the range [b, c), otherwise %false. 538 */ 539 static inline bool time_in_range_open(u64 a, u64 b, u64 c) 540 { 541 return time_after_eq(a, b) && time_before(a, c); 542 } 543 544 545 /* 546 * Other helpers 547 */ 548 549 /* useful compiler attributes */ 550 #define likely(x) __builtin_expect(!!(x), 1) 551 #define unlikely(x) __builtin_expect(!!(x), 0) 552 #define __maybe_unused __attribute__((__unused__)) 553 554 /* 555 * READ/WRITE_ONCE() are from kernel (include/asm-generic/rwonce.h). They 556 * prevent compiler from caching, redoing or reordering reads or writes. 557 */ 558 typedef __u8 __attribute__((__may_alias__)) __u8_alias_t; 559 typedef __u16 __attribute__((__may_alias__)) __u16_alias_t; 560 typedef __u32 __attribute__((__may_alias__)) __u32_alias_t; 561 typedef __u64 __attribute__((__may_alias__)) __u64_alias_t; 562 563 static __always_inline void __read_once_size(const volatile void *p, void *res, int size) 564 { 565 switch (size) { 566 case 1: *(__u8_alias_t *) res = *(volatile __u8_alias_t *) p; break; 567 case 2: *(__u16_alias_t *) res = *(volatile __u16_alias_t *) p; break; 568 case 4: *(__u32_alias_t *) res = *(volatile __u32_alias_t *) p; break; 569 case 8: *(__u64_alias_t *) res = *(volatile __u64_alias_t *) p; break; 570 default: 571 barrier(); 572 __builtin_memcpy((void *)res, (const void *)p, size); 573 barrier(); 574 } 575 } 576 577 static __always_inline void __write_once_size(volatile void *p, void *res, int size) 578 { 579 switch (size) { 580 case 1: *(volatile __u8_alias_t *) p = *(__u8_alias_t *) res; break; 581 case 2: *(volatile __u16_alias_t *) p = *(__u16_alias_t *) res; break; 582 case 4: *(volatile __u32_alias_t *) p = *(__u32_alias_t *) res; break; 583 case 8: *(volatile __u64_alias_t *) p = *(__u64_alias_t *) res; break; 584 default: 585 barrier(); 586 __builtin_memcpy((void *)p, (const void *)res, size); 587 barrier(); 588 } 589 } 590 591 /* 592 * __unqual_typeof(x) - Declare an unqualified scalar type, leaving 593 * non-scalar types unchanged, 594 * 595 * Prefer C11 _Generic for better compile-times and simpler code. Note: 'char' 596 * is not type-compatible with 'signed char', and we define a separate case. 597 * 598 * This is copied verbatim from kernel's include/linux/compiler_types.h, but 599 * with default expression (for pointers) changed from (x) to (typeof(x)0). 600 * 601 * This is because LLVM has a bug where for lvalue (x), it does not get rid of 602 * an extra address_space qualifier, but does in case of rvalue (typeof(x)0). 603 * Hence, for pointers, we need to create an rvalue expression to get the 604 * desired type. See https://github.com/llvm/llvm-project/issues/53400. 605 */ 606 #define __scalar_type_to_expr_cases(type) \ 607 unsigned type : (unsigned type)0, signed type : (signed type)0 608 609 #define __unqual_typeof(x) \ 610 typeof(_Generic((x), \ 611 char: (char)0, \ 612 __scalar_type_to_expr_cases(char), \ 613 __scalar_type_to_expr_cases(short), \ 614 __scalar_type_to_expr_cases(int), \ 615 __scalar_type_to_expr_cases(long), \ 616 __scalar_type_to_expr_cases(long long), \ 617 default: (typeof(x))0)) 618 619 #define READ_ONCE(x) \ 620 ({ \ 621 union { __unqual_typeof(x) __val; char __c[1]; } __u = \ 622 { .__c = { 0 } }; \ 623 __read_once_size((__unqual_typeof(x) *)&(x), __u.__c, sizeof(x)); \ 624 __u.__val; \ 625 }) 626 627 #define WRITE_ONCE(x, val) \ 628 ({ \ 629 union { __unqual_typeof(x) __val; char __c[1]; } __u = \ 630 { .__val = (val) }; \ 631 __write_once_size((__unqual_typeof(x) *)&(x), __u.__c, sizeof(x)); \ 632 __u.__val; \ 633 }) 634 635 /* 636 * log2_u32 - Compute the base 2 logarithm of a 32-bit exponential value. 637 * @v: The value for which we're computing the base 2 logarithm. 638 */ 639 static inline u32 log2_u32(u32 v) 640 { 641 u32 r; 642 u32 shift; 643 644 r = (v > 0xFFFF) << 4; v >>= r; 645 shift = (v > 0xFF) << 3; v >>= shift; r |= shift; 646 shift = (v > 0xF) << 2; v >>= shift; r |= shift; 647 shift = (v > 0x3) << 1; v >>= shift; r |= shift; 648 r |= (v >> 1); 649 return r; 650 } 651 652 /* 653 * log2_u64 - Compute the base 2 logarithm of a 64-bit exponential value. 654 * @v: The value for which we're computing the base 2 logarithm. 655 */ 656 static inline u32 log2_u64(u64 v) 657 { 658 u32 hi = v >> 32; 659 if (hi) 660 return log2_u32(hi) + 32 + 1; 661 else 662 return log2_u32(v) + 1; 663 } 664 665 /* 666 * Return a value proportionally scaled to the task's weight. 667 */ 668 static inline u64 scale_by_task_weight(const struct task_struct *p, u64 value) 669 { 670 return (value * p->scx.weight) / 100; 671 } 672 673 /* 674 * Return a value inversely proportional to the task's weight. 675 */ 676 static inline u64 scale_by_task_weight_inverse(const struct task_struct *p, u64 value) 677 { 678 return value * 100 / p->scx.weight; 679 } 680 681 682 #include "compat.bpf.h" 683 #include "enums.bpf.h" 684 685 #endif /* __SCX_COMMON_BPF_H */ 686