1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * Copyright (c) 2024 Meta Platforms, Inc. and affiliates. 4 * Copyright (c) 2024 Tejun Heo <tj@kernel.org> 5 * Copyright (c) 2024 David Vernet <dvernet@meta.com> 6 */ 7 #ifndef __SCX_COMPAT_BPF_H 8 #define __SCX_COMPAT_BPF_H 9 10 #define __COMPAT_ENUM_OR_ZERO(__type, __ent) \ 11 ({ \ 12 __type __ret = 0; \ 13 if (bpf_core_enum_value_exists(__type, __ent)) \ 14 __ret = __ent; \ 15 __ret; \ 16 }) 17 18 /* v6.12: 819513666966 ("sched_ext: Add cgroup support") */ 19 struct cgroup *scx_bpf_task_cgroup___new(struct task_struct *p) __ksym __weak; 20 21 #define scx_bpf_task_cgroup(p) \ 22 (bpf_ksym_exists(scx_bpf_task_cgroup___new) ? \ 23 scx_bpf_task_cgroup___new((p)) : NULL) 24 25 /* 26 * v6.13: The verb `dispatch` was too overloaded and confusing. kfuncs are 27 * renamed to unload the verb. 28 * 29 * scx_bpf_dispatch_from_dsq() and friends were added during v6.12 by 30 * 4c30f5ce4f7a ("sched_ext: Implement scx_bpf_dispatch[_vtime]_from_dsq()"). 31 * 32 * v7.1: scx_bpf_dsq_move_to_local___v2() to add @enq_flags. 33 */ 34 bool scx_bpf_dsq_move_to_local___v2(u64 dsq_id, u64 enq_flags) __ksym __weak; 35 bool scx_bpf_dsq_move_to_local___v1(u64 dsq_id) __ksym __weak; 36 void scx_bpf_dsq_move_set_slice___new(struct bpf_iter_scx_dsq *it__iter, u64 slice) __ksym __weak; 37 void scx_bpf_dsq_move_set_vtime___new(struct bpf_iter_scx_dsq *it__iter, u64 vtime) __ksym __weak; 38 bool scx_bpf_dsq_move___new(struct bpf_iter_scx_dsq *it__iter, struct task_struct *p, u64 dsq_id, u64 enq_flags) __ksym __weak; 39 bool scx_bpf_dsq_move_vtime___new(struct bpf_iter_scx_dsq *it__iter, struct task_struct *p, u64 dsq_id, u64 enq_flags) __ksym __weak; 40 41 bool scx_bpf_consume___old(u64 dsq_id) __ksym __weak; 42 void scx_bpf_dispatch_from_dsq_set_slice___old(struct bpf_iter_scx_dsq *it__iter, u64 slice) __ksym __weak; 43 void scx_bpf_dispatch_from_dsq_set_vtime___old(struct bpf_iter_scx_dsq *it__iter, u64 vtime) __ksym __weak; 44 bool scx_bpf_dispatch_from_dsq___old(struct bpf_iter_scx_dsq *it__iter, struct task_struct *p, u64 dsq_id, u64 enq_flags) __ksym __weak; 45 bool scx_bpf_dispatch_vtime_from_dsq___old(struct bpf_iter_scx_dsq *it__iter, struct task_struct *p, u64 dsq_id, u64 enq_flags) __ksym __weak; 46 47 #define scx_bpf_dsq_move_to_local(dsq_id, enq_flags) \ 48 (bpf_ksym_exists(scx_bpf_dsq_move_to_local___v2) ? \ 49 scx_bpf_dsq_move_to_local___v2((dsq_id), (enq_flags)) : \ 50 (bpf_ksym_exists(scx_bpf_dsq_move_to_local___v1) ? \ 51 scx_bpf_dsq_move_to_local___v1((dsq_id)) : \ 52 scx_bpf_consume___old((dsq_id)))) 53 54 #define scx_bpf_dsq_move_set_slice(it__iter, slice) \ 55 (bpf_ksym_exists(scx_bpf_dsq_move_set_slice___new) ? \ 56 scx_bpf_dsq_move_set_slice___new((it__iter), (slice)) : \ 57 (bpf_ksym_exists(scx_bpf_dispatch_from_dsq_set_slice___old) ? \ 58 scx_bpf_dispatch_from_dsq_set_slice___old((it__iter), (slice)) : \ 59 (void)0)) 60 61 #define scx_bpf_dsq_move_set_vtime(it__iter, vtime) \ 62 (bpf_ksym_exists(scx_bpf_dsq_move_set_vtime___new) ? \ 63 scx_bpf_dsq_move_set_vtime___new((it__iter), (vtime)) : \ 64 (bpf_ksym_exists(scx_bpf_dispatch_from_dsq_set_vtime___old) ? \ 65 scx_bpf_dispatch_from_dsq_set_vtime___old((it__iter), (vtime)) : \ 66 (void)0)) 67 68 #define scx_bpf_dsq_move(it__iter, p, dsq_id, enq_flags) \ 69 (bpf_ksym_exists(scx_bpf_dsq_move___new) ? \ 70 scx_bpf_dsq_move___new((it__iter), (p), (dsq_id), (enq_flags)) : \ 71 (bpf_ksym_exists(scx_bpf_dispatch_from_dsq___old) ? \ 72 scx_bpf_dispatch_from_dsq___old((it__iter), (p), (dsq_id), (enq_flags)) : \ 73 false)) 74 75 #define scx_bpf_dsq_move_vtime(it__iter, p, dsq_id, enq_flags) \ 76 (bpf_ksym_exists(scx_bpf_dsq_move_vtime___new) ? \ 77 scx_bpf_dsq_move_vtime___new((it__iter), (p), (dsq_id), (enq_flags)) : \ 78 (bpf_ksym_exists(scx_bpf_dispatch_vtime_from_dsq___old) ? \ 79 scx_bpf_dispatch_vtime_from_dsq___old((it__iter), (p), (dsq_id), (enq_flags)) : \ 80 false)) 81 82 /* 83 * v6.15: 950ad93df2fc ("bpf: add kfunc for populating cpumask bits") 84 * 85 * Compat macro will be dropped on v6.19 release. 86 */ 87 int bpf_cpumask_populate(struct cpumask *dst, void *src, size_t src__sz) __ksym __weak; 88 89 #define __COMPAT_bpf_cpumask_populate(cpumask, src, size__sz) \ 90 (bpf_ksym_exists(bpf_cpumask_populate) ? \ 91 (bpf_cpumask_populate(cpumask, src, size__sz)) : -EOPNOTSUPP) 92 93 /* 94 * v6.19: Introduce lockless peek API for user DSQs. 95 * 96 * Preserve the following macro until v6.21. 97 */ 98 static inline struct task_struct *__COMPAT_scx_bpf_dsq_peek(u64 dsq_id) 99 { 100 struct task_struct *p = NULL; 101 struct bpf_iter_scx_dsq it; 102 103 if (bpf_ksym_exists(scx_bpf_dsq_peek)) 104 return scx_bpf_dsq_peek(dsq_id); 105 if (!bpf_iter_scx_dsq_new(&it, dsq_id, 0)) 106 p = bpf_iter_scx_dsq_next(&it); 107 bpf_iter_scx_dsq_destroy(&it); 108 return p; 109 } 110 111 /* 112 * v7.1: scx_bpf_sub_dispatch() for sub-sched dispatch. Preserve until 113 * we drop the compat layer for older kernels that lack the kfunc. 114 */ 115 bool scx_bpf_sub_dispatch___compat(u64 cgroup_id) __ksym __weak; 116 117 static inline bool scx_bpf_sub_dispatch(u64 cgroup_id) 118 { 119 if (bpf_ksym_exists(scx_bpf_sub_dispatch___compat)) 120 return scx_bpf_sub_dispatch___compat(cgroup_id); 121 return false; 122 } 123 124 /* 125 * v7.3: scx_bpf_cid_override() for explicit cid and shard mapping. Ignore if 126 * missing. 127 */ 128 void scx_bpf_cid_override___compat(const s32 *cpu_to_cid, u32 cpu_to_cid__sz, 129 const s32 *shard_start, u32 shard_start__sz) __ksym __weak; 130 131 static inline void scx_bpf_cid_override(const s32 *cpu_to_cid, u32 cpu_to_cid__sz, 132 const s32 *shard_start, u32 shard_start__sz) 133 { 134 if (bpf_ksym_exists(scx_bpf_cid_override___compat)) 135 scx_bpf_cid_override___compat(cpu_to_cid, cpu_to_cid__sz, 136 shard_start, shard_start__sz); 137 } 138 139 /** 140 * __COMPAT_is_enq_cpu_selected - Test if SCX_ENQ_CPU_SELECTED is on 141 * in a compatible way. We will preserve this __COMPAT helper until v6.16. 142 * 143 * @enq_flags: enqueue flags from ops.enqueue() 144 * 145 * Return: True if SCX_ENQ_CPU_SELECTED is turned on in @enq_flags 146 */ 147 static inline bool __COMPAT_is_enq_cpu_selected(u64 enq_flags) 148 { 149 #ifdef HAVE_SCX_ENQ_CPU_SELECTED 150 /* 151 * This is the case that a BPF code compiled against vmlinux.h 152 * where the enum SCX_ENQ_CPU_SELECTED exists. 153 */ 154 155 /* 156 * We should temporarily suspend the macro expansion of 157 * 'SCX_ENQ_CPU_SELECTED'. This avoids 'SCX_ENQ_CPU_SELECTED' being 158 * rewritten to '__SCX_ENQ_CPU_SELECTED' when 'SCX_ENQ_CPU_SELECTED' 159 * is defined in 'scripts/gen_enums.py'. 160 */ 161 #pragma push_macro("SCX_ENQ_CPU_SELECTED") 162 #undef SCX_ENQ_CPU_SELECTED 163 u64 flag; 164 165 /* 166 * When the kernel did not have SCX_ENQ_CPU_SELECTED, 167 * select_task_rq_scx() has never been skipped. Thus, this case 168 * should be considered that the CPU has already been selected. 169 */ 170 if (!bpf_core_enum_value_exists(enum scx_enq_flags, 171 SCX_ENQ_CPU_SELECTED)) 172 return true; 173 174 flag = bpf_core_enum_value(enum scx_enq_flags, SCX_ENQ_CPU_SELECTED); 175 return enq_flags & flag; 176 177 /* 178 * Once done, resume the macro expansion of 'SCX_ENQ_CPU_SELECTED'. 179 */ 180 #pragma pop_macro("SCX_ENQ_CPU_SELECTED") 181 #else 182 /* 183 * This is the case that a BPF code compiled against vmlinux.h 184 * where the enum SCX_ENQ_CPU_SELECTED does NOT exist. 185 */ 186 return true; 187 #endif /* HAVE_SCX_ENQ_CPU_SELECTED */ 188 } 189 190 191 #define scx_bpf_now() \ 192 (bpf_ksym_exists(scx_bpf_now) ? \ 193 scx_bpf_now() : \ 194 bpf_ktime_get_ns()) 195 196 /* 197 * v6.15: Introduce event counters. 198 * 199 * Preserve the following macro until v6.17. 200 */ 201 #define __COMPAT_scx_bpf_events(events, size) \ 202 (bpf_ksym_exists(scx_bpf_events) ? \ 203 scx_bpf_events(events, size) : ({})) 204 205 /* 206 * v6.15: Introduce NUMA-aware kfuncs to operate with per-node idle 207 * cpumasks. 208 * 209 * Preserve the following __COMPAT_scx_*_node macros until v6.17. 210 */ 211 #define __COMPAT_scx_bpf_nr_node_ids() \ 212 (bpf_ksym_exists(scx_bpf_nr_node_ids) ? \ 213 scx_bpf_nr_node_ids() : 1U) 214 215 #define __COMPAT_scx_bpf_cpu_node(cpu) \ 216 (bpf_ksym_exists(scx_bpf_cpu_node) ? \ 217 scx_bpf_cpu_node(cpu) : 0) 218 219 #define __COMPAT_scx_bpf_get_idle_cpumask_node(node) \ 220 (bpf_ksym_exists(scx_bpf_get_idle_cpumask_node) ? \ 221 scx_bpf_get_idle_cpumask_node(node) : \ 222 scx_bpf_get_idle_cpumask()) \ 223 224 #define __COMPAT_scx_bpf_get_idle_smtmask_node(node) \ 225 (bpf_ksym_exists(scx_bpf_get_idle_smtmask_node) ? \ 226 scx_bpf_get_idle_smtmask_node(node) : \ 227 scx_bpf_get_idle_smtmask()) 228 229 #define __COMPAT_scx_bpf_pick_idle_cpu_node(cpus_allowed, node, flags) \ 230 (bpf_ksym_exists(scx_bpf_pick_idle_cpu_node) ? \ 231 scx_bpf_pick_idle_cpu_node(cpus_allowed, node, flags) : \ 232 scx_bpf_pick_idle_cpu(cpus_allowed, flags)) 233 234 #define __COMPAT_scx_bpf_pick_any_cpu_node(cpus_allowed, node, flags) \ 235 (bpf_ksym_exists(scx_bpf_pick_any_cpu_node) ? \ 236 scx_bpf_pick_any_cpu_node(cpus_allowed, node, flags) : \ 237 scx_bpf_pick_any_cpu(cpus_allowed, flags)) 238 239 /* 240 * v6.19: To work around BPF maximum parameter limit, the following kfuncs are 241 * replaced with variants that pack scalar arguments in a struct. Wrappers are 242 * provided to maintain source compatibility. 243 * 244 * v6.13: scx_bpf_dsq_insert_vtime() renaming is also handled here. See the 245 * block on dispatch renaming above for more details. 246 * 247 * The kernel will carry the compat variants until v6.23 to maintain binary 248 * compatibility. After v6.23 release, remove the compat handling and move the 249 * wrappers to common.bpf.h. 250 */ 251 s32 scx_bpf_select_cpu_and___compat(struct task_struct *p, s32 prev_cpu, u64 wake_flags, 252 const struct cpumask *cpus_allowed, u64 flags) __ksym __weak; 253 void scx_bpf_dispatch_vtime___compat(struct task_struct *p, u64 dsq_id, u64 slice, u64 vtime, u64 enq_flags) __ksym __weak; 254 void scx_bpf_dsq_insert_vtime___compat(struct task_struct *p, u64 dsq_id, u64 slice, u64 vtime, u64 enq_flags) __ksym __weak; 255 256 /** 257 * scx_bpf_select_cpu_and - Pick an idle CPU usable by task @p 258 * @p: task_struct to select a CPU for 259 * @prev_cpu: CPU @p was on previously 260 * @wake_flags: %SCX_WAKE_* flags 261 * @cpus_allowed: cpumask of allowed CPUs 262 * @flags: %SCX_PICK_IDLE* flags 263 * 264 * Inline wrapper that packs scalar arguments into a struct and calls 265 * __scx_bpf_select_cpu_and(). See __scx_bpf_select_cpu_and() for details. 266 */ 267 static inline s32 268 scx_bpf_select_cpu_and(struct task_struct *p, s32 prev_cpu, u64 wake_flags, 269 const struct cpumask *cpus_allowed, u64 flags) 270 { 271 if (bpf_core_type_exists(struct scx_bpf_select_cpu_and_args)) { 272 struct scx_bpf_select_cpu_and_args args = { 273 .prev_cpu = prev_cpu, 274 .wake_flags = wake_flags, 275 .flags = flags, 276 }; 277 278 return __scx_bpf_select_cpu_and(p, cpus_allowed, &args); 279 } else { 280 return scx_bpf_select_cpu_and___compat(p, prev_cpu, wake_flags, 281 cpus_allowed, flags); 282 } 283 } 284 285 /* 286 * scx_bpf_select_cpu_and() is now an inline wrapper. Use this instead of 287 * bpf_ksym_exists(scx_bpf_select_cpu_and) to test availability. 288 */ 289 #define __COMPAT_HAS_scx_bpf_select_cpu_and \ 290 (bpf_core_type_exists(struct scx_bpf_select_cpu_and_args) || \ 291 bpf_ksym_exists(scx_bpf_select_cpu_and___compat)) 292 293 /** 294 * scx_bpf_dsq_insert_vtime - Insert a task into the vtime priority queue of a DSQ 295 * @p: task_struct to insert 296 * @dsq_id: DSQ to insert into 297 * @slice: duration @p can run for in nsecs, 0 to keep the current value 298 * @vtime: @p's ordering inside the vtime-sorted queue of the target DSQ 299 * @enq_flags: SCX_ENQ_* 300 * 301 * Inline wrapper that packs scalar arguments into a struct and calls 302 * __scx_bpf_dsq_insert_vtime(). See __scx_bpf_dsq_insert_vtime() for details. 303 */ 304 static inline bool 305 scx_bpf_dsq_insert_vtime(struct task_struct *p, u64 dsq_id, u64 slice, u64 vtime, 306 u64 enq_flags) 307 { 308 if (bpf_core_type_exists(struct scx_bpf_dsq_insert_vtime_args)) { 309 struct scx_bpf_dsq_insert_vtime_args args = { 310 .dsq_id = dsq_id, 311 .slice = slice, 312 .vtime = vtime, 313 .enq_flags = enq_flags, 314 }; 315 316 return __scx_bpf_dsq_insert_vtime(p, &args); 317 } else if (bpf_ksym_exists(scx_bpf_dsq_insert_vtime___compat)) { 318 scx_bpf_dsq_insert_vtime___compat(p, dsq_id, slice, vtime, 319 enq_flags); 320 return true; 321 } else { 322 scx_bpf_dispatch_vtime___compat(p, dsq_id, slice, vtime, 323 enq_flags); 324 return true; 325 } 326 } 327 328 /* 329 * v6.19: scx_bpf_dsq_insert() now returns bool instead of void. Move 330 * scx_bpf_dsq_insert() decl to common.bpf.h and drop compat helper after v6.22. 331 * The extra ___compat suffix is to work around libbpf not ignoring __SUFFIX on 332 * kernel side. The entire suffix can be dropped later. 333 * 334 * v6.13: scx_bpf_dsq_insert() renaming is also handled here. See the block on 335 * dispatch renaming above for more details. 336 */ 337 bool scx_bpf_dsq_insert___v2___compat(struct task_struct *p, u64 dsq_id, u64 slice, u64 enq_flags) __ksym __weak; 338 void scx_bpf_dsq_insert___v1(struct task_struct *p, u64 dsq_id, u64 slice, u64 enq_flags) __ksym __weak; 339 void scx_bpf_dispatch___compat(struct task_struct *p, u64 dsq_id, u64 slice, u64 enq_flags) __ksym __weak; 340 341 static inline bool 342 scx_bpf_dsq_insert(struct task_struct *p, u64 dsq_id, u64 slice, u64 enq_flags) 343 { 344 if (bpf_ksym_exists(scx_bpf_dsq_insert___v2___compat)) { 345 return scx_bpf_dsq_insert___v2___compat(p, dsq_id, slice, enq_flags); 346 } else if (bpf_ksym_exists(scx_bpf_dsq_insert___v1)) { 347 scx_bpf_dsq_insert___v1(p, dsq_id, slice, enq_flags); 348 return true; 349 } else { 350 scx_bpf_dispatch___compat(p, dsq_id, slice, enq_flags); 351 return true; 352 } 353 } 354 355 /* 356 * v6.19: scx_bpf_task_set_slice() and scx_bpf_task_set_dsq_vtime() added to for 357 * sub-sched authority checks. Drop the wrappers and move the decls to 358 * common.bpf.h after v6.22. 359 */ 360 bool scx_bpf_task_set_slice___new(struct task_struct *p, u64 slice) __ksym __weak; 361 bool scx_bpf_task_set_dsq_vtime___new(struct task_struct *p, u64 vtime) __ksym __weak; 362 363 static inline void scx_bpf_task_set_slice(struct task_struct *p, u64 slice) 364 { 365 if (bpf_ksym_exists(scx_bpf_task_set_slice___new)) 366 scx_bpf_task_set_slice___new(p, slice); 367 else 368 p->scx.slice = slice; 369 } 370 371 static inline void scx_bpf_task_set_dsq_vtime(struct task_struct *p, u64 vtime) 372 { 373 if (bpf_ksym_exists(scx_bpf_task_set_dsq_vtime___new)) 374 scx_bpf_task_set_dsq_vtime___new(p, vtime); 375 else 376 p->scx.dsq_vtime = vtime; 377 } 378 379 /* 380 * v6.19: The new void variant can be called from anywhere while the older v1 381 * variant can only be called from ops.cpu_release(). The double ___ prefixes on 382 * the v2 variant need to be removed once libbpf is updated to ignore ___ prefix 383 * on kernel side. Drop the wrapper and move the decl to common.bpf.h after 384 * v6.22. 385 */ 386 u32 scx_bpf_reenqueue_local___v1(void) __ksym __weak; 387 void scx_bpf_reenqueue_local___v2___compat(void) __ksym __weak; 388 389 static inline bool __COMPAT_scx_bpf_reenqueue_local_from_anywhere(void) 390 { 391 return bpf_ksym_exists(scx_bpf_reenqueue_local___v2___compat); 392 } 393 394 static inline void scx_bpf_reenqueue_local(void) 395 { 396 if (__COMPAT_scx_bpf_reenqueue_local_from_anywhere()) 397 scx_bpf_reenqueue_local___v2___compat(); 398 else 399 scx_bpf_reenqueue_local___v1(); 400 } 401 402 /* 403 * v7.1: New scx_bpf_dsq_reenq() that allows re-enqueues on more DSQs. This 404 * will eventually deprecate scx_bpf_reenqueue_local(). 405 */ 406 void scx_bpf_dsq_reenq___compat(u64 dsq_id, u64 reenq_flags) __ksym __weak; 407 408 static inline bool __COMPAT_has_generic_reenq(void) 409 { 410 return bpf_ksym_exists(scx_bpf_dsq_reenq___compat); 411 } 412 413 static inline void scx_bpf_dsq_reenq(u64 dsq_id, u64 reenq_flags) 414 { 415 if (bpf_ksym_exists(scx_bpf_dsq_reenq___compat)) 416 scx_bpf_dsq_reenq___compat(dsq_id, reenq_flags); 417 else if (dsq_id == SCX_DSQ_LOCAL && reenq_flags == 0) 418 scx_bpf_reenqueue_local(); 419 else 420 scx_bpf_error("kernel too old to reenqueue foreign local or user DSQs"); 421 } 422 423 /* 424 * Define sched_ext_ops. See compat.h::SCX_OPS_OPEN() for how backward 425 * compatibility is handled (this macro can be expanded to emit multiple 426 * variants for incompatible op changes; SCX_OPS_OPEN() handles purely 427 * additive changes at load time). 428 */ 429 #define SCX_OPS_DEFINE(__name, ...) \ 430 SEC(".struct_ops.link") \ 431 struct sched_ext_ops __name = { \ 432 __VA_ARGS__, \ 433 }; 434 435 /* 436 * Define a cid-form sched_ext_ops. Programs targeting this struct_ops type 437 * use cid-form callback signatures (select_cid, set_cmask, cid_online/offline, 438 * dispatch with cid arg, etc.) and may only call the cid-form scx_bpf_* 439 * kfuncs (kick_cid, task_cid, this_cid, ...). 440 */ 441 #define SCX_OPS_CID_DEFINE(__name, ...) \ 442 SEC(".struct_ops.link") \ 443 struct sched_ext_ops_cid __name = { \ 444 __VA_ARGS__, \ 445 }; 446 447 #endif /* __SCX_COMPAT_BPF_H */ 448