/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (c) 2022 Meta Platforms, Inc. and affiliates.
* Copyright (c) 2022 Tejun Heo <tj@kernel.org>
* Copyright (c) 2022 David Vernet <dvernet@meta.com>
*/
#ifndef __SCX_COMMON_BPF_H
#define __SCX_COMMON_BPF_H
/*
* The generated kfunc prototypes in vmlinux.h are missing address space
* attributes which cause build failures. For now, suppress the generated
* prototypes. See https://github.com/sched-ext/scx/issues/1111.
*/
#define BPF_NO_KFUNC_PROTOTYPES
#ifdef LSP
#define __bpf__
#include "../vmlinux.h"
#else
#include "vmlinux.h"
#endif
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
#include <asm-generic/errno.h>
#include "user_exit_info.bpf.h"
#include "enum_defs.autogen.h"
#define PF_IDLE 0x00000002 /* I am an IDLE thread */
#define PF_IO_WORKER 0x00000010 /* Task is an IO worker */
#define PF_WQ_WORKER 0x00000020 /* I'm a workqueue worker */
#define PF_KCOMPACTD 0x00010000 /* I am kcompactd */
#define PF_KSWAPD 0x00020000 /* I am kswapd */
#define PF_KTHREAD 0x00200000 /* I am a kernel thread */
#define PF_EXITING 0x00000004
#define CLOCK_MONOTONIC 1
#ifndef NR_CPUS
#define NR_CPUS 1024
#endif
#ifndef NUMA_NO_NODE
#define NUMA_NO_NODE (-1)
#endif
extern int LINUX_KERNEL_VERSION __kconfig;
extern const char CONFIG_CC_VERSION_TEXT[64] __kconfig __weak;
extern const char CONFIG_LOCALVERSION[64] __kconfig __weak;
/*
* Earlier versions of clang/pahole lost upper 32bits in 64bit enums which can
* lead to really confusing misbehaviors. Let's trigger a build failure.
*/
static inline void ___vmlinux_h_sanity_check___(void)
{
_Static_assert(SCX_DSQ_FLAG_BUILTIN,
"bpftool generated vmlinux.h is missing high bits for 64bit enums, upgrade clang and pahole");
}
s32 scx_bpf_create_dsq(u64 dsq_id, s32 node) __ksym;
s32 scx_bpf_select_cpu_dfl(struct task_struct *p, s32 prev_cpu, u64 wake_flags, bool *is_idle) __ksym;
s32 __scx_bpf_select_cpu_and(struct task_struct *p, const struct cpumask *cpus_allowed,
struct scx_bpf_select_cpu_and_args *args) __ksym __weak;
bool __scx_bpf_dsq_insert_vtime(struct task_struct *p, struct scx_bpf_dsq_insert_vtime_args *args) __ksym __weak;
u32 scx_bpf_dispatch_nr_slots(void) __ksym;
void scx_bpf_dispatch_cancel(void) __ksym;
void scx_bpf_kick_cpu(s32 cpu, u64 flags) __ksym;
s32 scx_bpf_dsq_nr_queued(u64 dsq_id) __ksym;
void scx_bpf_destroy_dsq(u64 dsq_id) __ksym;
struct task_struct *scx_bpf_dsq_peek(u64 dsq_id) __ksym __weak;
int bpf_iter_scx_dsq_new(struct bpf_iter_scx_dsq *it, u64 dsq_id, u64 flags) __ksym __weak;
struct task_struct *bpf_iter_scx_dsq_next(struct bpf_iter_scx_dsq *it) __ksym __weak;
void bpf_iter_scx_dsq_destroy(struct bpf_iter_scx_dsq *it) __ksym __weak;
void scx_bpf_exit_bstr(s64 exit_code, char *fmt, unsigned long long *data, u32 data__sz) __ksym __weak;
void scx_bpf_error_bstr(char *fmt, unsigned long long *data, u32 data_len) __ksym;
void scx_bpf_dump_bstr(char *fmt, unsigned long long *data, u32 data_len) __ksym __weak;
u32 scx_bpf_cpuperf_cap(s32 cpu) __ksym __weak;
u32 scx_bpf_cpuperf_cur(s32 cpu) __ksym __weak;
void scx_bpf_cpuperf_set(s32 cpu, u32 perf) __ksym __weak;
u32 scx_bpf_nr_node_ids(void) __ksym __weak;
u32 scx_bpf_nr_cpu_ids(void) __ksym __weak;
int scx_bpf_cpu_node(s32 cpu) __ksym __weak;
const struct cpumask *scx_bpf_get_possible_cpumask(void) __ksym __weak;
const struct cpumask *scx_bpf_get_online_cpumask(void) __ksym __weak;
void scx_bpf_put_cpumask(const struct cpumask *cpumask) __ksym __weak;
const struct cpumask *scx_bpf_get_idle_cpumask_node(int node) __ksym __weak;
const struct cpumask *scx_bpf_get_idle_cpumask(void) __ksym;
const struct cpumask *scx_bpf_get_idle_smtmask_node(int node) __ksym __weak;
const struct cpumask *scx_bpf_get_idle_smtmask(void) __ksym;
void scx_bpf_put_idle_cpumask(const struct cpumask *cpumask) __ksym;
bool scx_bpf_test_and_clear_cpu_idle(s32 cpu) __ksym;
s32 scx_bpf_pick_idle_cpu_node(const cpumask_t *cpus_allowed, int node, u64 flags) __ksym __weak;
s32 scx_bpf_pick_idle_cpu(const cpumask_t *cpus_allowed, u64 flags) __ksym;
s32 scx_bpf_pick_any_cpu_node(const cpumask_t *cpus_allowed, int node, u64 flags) __ksym __weak;
s32 scx_bpf_pick_any_cpu(const cpumask_t *cpus_allowed, u64 flags) __ksym;
bool scx_bpf_task_running(const struct task_struct *p) __ksym;
s32 scx_bpf_task_cpu(const struct task_struct *p) __ksym;
struct rq *scx_bpf_locked_rq(void) __ksym;
struct task_struct *scx_bpf_cpu_curr(s32 cpu) __ksym __weak;
struct task_struct *scx_bpf_tid_to_task(u64 tid) __ksym __weak;
u64 scx_bpf_now(void) __ksym __weak;
void scx_bpf_events(struct scx_event_stats *events, size_t events__sz) __ksym __weak;
s32 scx_bpf_cpu_to_cid(s32 cpu) __ksym __weak;
s32 scx_bpf_cid_to_cpu(s32 cid) __ksym __weak;
void scx_bpf_cid_topo(s32 cid, struct scx_cid_topo *out) __ksym __weak;
void scx_bpf_kick_cid(s32 cid, u64 flags) __ksym __weak;
s32 scx_bpf_task_cid(const struct task_struct *p) __ksym __weak;
s32 scx_bpf_this_cid(void) __ksym __weak;
struct task_struct *scx_bpf_cid_curr(s32 cid) __ksym __weak;
u32 scx_bpf_nr_cids(void) __ksym __weak;
u32 scx_bpf_nr_online_cids(void) __ksym __weak;
u32 scx_bpf_cidperf_cap(s32 cid) __ksym __weak;
u32 scx_bpf_cidperf_cur(s32 cid) __ksym __weak;
s32 scx_bpf_cidperf_set(s32 cid, u32 perf) __ksym __weak;
/* sub-scheduler cap control, scx_bpf_sub_caps() cgroup_id 0 == self */
s32 scx_bpf_sub_grant(u64 cgroup_id, u64 caps, const struct scx_cmask *cmask,
struct scx_cmask *denied) __ksym __weak;
void scx_bpf_sub_revoke(u64 cgroup_id, u64 caps, const struct scx_cmask *cmask) __ksym __weak;
s32 scx_bpf_sub_caps(u64 cgroup_id, u64 caps, struct scx_cmask *out) __ksym __weak;
s32 scx_bpf_sub_kill_bstr(u64 cgroup_id, char *fmt,
unsigned long long *data, u32 data__sz) __ksym __weak;
/*
* Use the following as @it__iter when calling scx_bpf_dsq_move[_vtime]() from
* within bpf_for_each() loops.
*/
#define BPF_FOR_EACH_ITER (&___it)
#define scx_read_event(e, name) \
(bpf_core_field_exists((e)->name) ? (e)->name : 0)
static inline __attribute__((format(printf, 1, 2)))
void ___scx_bpf_bstr_format_checker(const char *fmt, ...) {}
#define SCX_STRINGIFY(x) #x
#define SCX_TOSTRING(x) SCX_STRINGIFY(x)
/*
* Helper macro for initializing the fmt and variadic argument inputs to both
* bstr exit kfuncs. Callers to this function should use ___fmt and ___param to
* refer to the initialized list of inputs to the bstr kfunc.
*/
#define scx_bpf_bstr_preamble(fmt, args...) \
static char ___fmt[] = fmt; \
/* \
* Note that __param[] must have at least one \
* element to keep the verifier happy. \
*/ \
unsigned long long ___param[___bpf_narg(args) ?: 1] = {}; \
\
_Pragma("GCC diagnostic push") \
_Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \
___bpf_fill(___param, args); \
_Pragma("GCC diagnostic pop")
/*
* scx_bpf_exit() wraps the scx_bpf_exit_bstr() kfunc with variadic arguments
* instead of an array of u64. Using this macro will cause the scheduler to
* exit cleanly with the specified exit code being passed to user space.
*/
#define scx_bpf_exit(code, fmt, args...) \
({ \
scx_bpf_bstr_preamble(fmt, args) \
scx_bpf_exit_bstr(code, ___fmt, ___param, sizeof(___param)); \
___scx_bpf_bstr_format_checker(fmt, ##args); \
})
/*
* scx_bpf_sub_kill() wraps the scx_bpf_sub_kill_bstr() kfunc with variadic
* arguments instead of an array of u64. It kills the direct child sub-scheduler
* @cgid, passing the formatted reason to its user space, and evaluates to the
* kfunc's return value. On a kernel without sub-scheduler support the kfunc is
* absent and it returns -EOPNOTSUPP.
*/
#define scx_bpf_sub_kill(cgid, fmt, args...) \
({ \
scx_bpf_bstr_preamble(fmt, args) \
___scx_bpf_bstr_format_checker(fmt, ##args); \
bpf_ksym_exists(scx_bpf_sub_kill_bstr) ? \
scx_bpf_sub_kill_bstr((cgid), ___fmt, ___param, \
sizeof(___param)) : -EOPNOTSUPP; \
})
/*
* scx_bpf_error() wraps the scx_bpf_error_bstr() kfunc with variadic arguments
* instead of an array of u64. Invoking this macro will cause the scheduler to
* exit in an erroneous state, with diagnostic information being passed to the
* user. It appends the file and line number to aid debugging.
*/
#define scx_bpf_error(fmt, args...) \
({ \
scx_bpf_bstr_preamble( \
__FILE__ ":" SCX_TOSTRING(__LINE__) ": " fmt, ##args) \
scx_bpf_error_bstr(___fmt, ___param, sizeof(___param)); \
___scx_bpf_bstr_format_checker( \
__FILE__ ":" SCX_TOSTRING(__LINE__) ": " fmt, ##args); \
})
/*
* scx_bpf_dump() wraps the scx_bpf_dump_bstr() kfunc with variadic arguments
* instead of an array of u64. To be used from ops.dump() and friends.
*/
#define scx_bpf_dump(fmt, args...) \
({ \
scx_bpf_bstr_preamble(fmt, args) \
scx_bpf_dump_bstr(___fmt, ___param, sizeof(___param)); \
___scx_bpf_bstr_format_checker(fmt, ##args); \
})
/*
* scx_bpf_dump_header() is a wrapper around scx_bpf_dump that adds a header
* of system information for debugging.
*/
#define scx_bpf_dump_header() \
({ \
scx_bpf_dump("kernel: %d.%d.%d %s\ncc: %s\n", \
LINUX_KERNEL_VERSION >> 16, \
LINUX_KERNEL_VERSION >> 8 & 0xFF, \
LINUX_KERNEL_VERSION & 0xFF, \
CONFIG_LOCALVERSION, \
CONFIG_CC_VERSION_TEXT); \
})
#define BPF_STRUCT_OPS(name, args...) \
SEC("struct_ops/"#name) \
BPF_PROG(name, ##args)
#define BPF_STRUCT_OPS_SLEEPABLE(name, args...) \
SEC("struct_ops.s/"#name) \
BPF_PROG(name, ##args)
/**
* RESIZABLE_ARRAY - Generates annotations for an array that may be resized
* @elfsec: the data section of the BPF program in which to place the array
* @arr: the name of the array
*
* libbpf has an API for setting map value sizes. Since data sections (i.e.
* bss, data, rodata) themselves are maps, a data section can be resized. If
* a data section has an array as its last element, the BTF info for that
* array will be adjusted so that length of the array is extended to meet the
* new length of the data section. This macro annotates an array to have an
* element count of one with the assumption that this array can be resized
* within the userspace program. It also annotates the section specifier so
* this array exists in a custom sub data section which can be resized
* independently.
*
* See RESIZE_ARRAY() for the userspace convenience macro for resizing an
* array declared with RESIZABLE_ARRAY().
*/
#define RESIZABLE_ARRAY(elfsec, arr) arr[1] SEC("."#elfsec"."#arr)
/**
* MEMBER_VPTR - Obtain the verified pointer to a struct or array member
* @base: struct or array to index
* @member: dereferenced member (e.g. .field, [idx0][idx1], .field[idx0] ...)
*
* The verifier often gets confused by the instruction sequence the compiler
* generates for indexing struct fields or arrays. This macro forces the
* compiler to generate a code sequence which first calculates the byte offset,
* checks it against the struct or array size and add that byte offset to
* generate the pointer to the member to help the verifier.
*
* Ideally, we want to abort if the calculated offset is out-of-bounds. However,
* BPF currently doesn't support abort, so evaluate to %NULL instead. The caller
* must check for %NULL and take appropriate action to appease the verifier. To
* avoid confusing the verifier, it's best to check for %NULL and dereference
* immediately.
*
* vptr = MEMBER_VPTR(my_array, [i][j]);
* if (!vptr)
* return error;
* *vptr = new_value;
*
* sizeof(@base) should encompass the memory area to be accessed and thus can't
* be a pointer to the area. Use `MEMBER_VPTR(*ptr, .member)` instead of
* `MEMBER_VPTR(ptr, ->member)`.
*/
#ifndef MEMBER_VPTR
#define MEMBER_VPTR(base, member) (typeof((base) member) *) \
({ \
u64 __base = (u64)&(base); \
u64 __addr = (u64)&((base) member) - __base; \
_Static_assert(sizeof(base) >= sizeof((base) member), \
"@base is smaller than @member, is @base a pointer?"); \
asm volatile ( \
"if %0 <= %[max] goto +2\n" \
"%0 = 0\n" \
"goto +1\n" \
"%0 += %1\n" \
: "+r"(__addr) \
: "r"(__base), \
[max]"i"(sizeof(base) - sizeof((base) member))); \
__addr; \
})
#endif /* MEMBER_VPTR */
/**
* ARRAY_ELEM_PTR - Obtain the verified pointer to an array element
* @arr: array to index into
* @i: array index
* @n: number of elements in array
*
* Similar to MEMBER_VPTR() but is intended for use with arrays where the
* element count needs to be explicit.
* It can be used in cases where a global array is defined with an initial
* size but is intended to be be resized before loading the BPF program.
* Without this version of the macro, MEMBER_VPTR() will use the compile time
* size of the array to compute the max, which will result in rejection by
* the verifier.
*/
#ifndef ARRAY_ELEM_PTR
#define ARRAY_ELEM_PTR(arr, i, n) (typeof(arr[i]) *) \
({ \
u64 __base = (u64)arr; \
u64 __addr = (u64)&(arr[i]) - __base; \
asm volatile ( \
"if %0 <= %[max] goto +2\n" \
"%0 = 0\n" \
"goto +1\n" \
"%0 += %1\n" \
: "+r"(__addr) \
: "r"(__base), \
[max]"r"(sizeof(arr[0]) * ((n) - 1))); \
__addr; \
})
#endif /* ARRAY_ELEM_PTR */
/**
* __sink - Hide @expr's value from the compiler and BPF verifier
* @expr: The expression whose value should be opacified
*
* No-op at runtime. The empty inline assembly with a read-write constraint
* ("+g") has two effects at compile/verify time:
*
* 1. Compiler: treats @expr as both read and written, preventing dead-code
* elimination and keeping @expr (and any side effects that produced it)
* alive.
*
* 2. BPF verifier: forgets the precise value/range of @expr ("makes it
* imprecise"). The verifier normally tracks exact ranges for every register
* and stack slot. While useful, precision means each distinct value creates a
* separate verifier state. Inside loops this leads to state explosion - each
* iteration carries different precise values so states never merge and the
* verifier explores every iteration individually.
*
* Example - preventing loop state explosion::
*
* u32 nr_intersects = 0, nr_covered = 0;
* __sink(nr_intersects);
* __sink(nr_covered);
* bpf_for(i, 0, nr_nodes) {
* if (intersects(cpumask, node_mask[i]))
* nr_intersects++;
* if (covers(cpumask, node_mask[i]))
* nr_covered++;
* }
*
* Without __sink(), the verifier tracks every possible (nr_intersects,
* nr_covered) pair across iterations, causing "BPF program is too large". With
* __sink(), the values become unknown scalars so all iterations collapse into
* one reusable state.
*
* Example - keeping a reference alive::
*
* struct task_struct *t = bpf_task_acquire(task);
* __sink(t);
*
* Follows the convention from BPF selftests (bpf_misc.h).
*/
#define __sink(expr) asm volatile ("" : "+g"(expr))
/*
* BPF declarations and helpers
*/
/* list and rbtree */
#define __contains(name, node) __attribute__((btf_decl_tag("contains:" #name ":" #node)))
#define private(name) SEC(".data." #name) __hidden __attribute__((aligned(8)))
void *bpf_obj_new_impl(__u64 local_type_id, void *meta) __ksym;
void bpf_obj_drop_impl(void *kptr, void *meta) __ksym;
#define bpf_obj_new(type) ((type *)bpf_obj_new_impl(bpf_core_type_id_local(type), NULL))
#define bpf_obj_drop(kptr) bpf_obj_drop_impl(kptr, NULL)
int bpf_list_push_front_impl(struct bpf_list_head *head,
struct bpf_list_node *node,
void *meta, __u64 off) __ksym;
#define bpf_list_push_front(head, node) bpf_list_push_front_impl(head, node, NULL, 0)
int bpf_list_push_back_impl(struct bpf_list_head *head,
struct bpf_list_node *node,
void *meta, __u64 off) __ksym;
#define bpf_list_push_back(head, node) bpf_list_push_back_impl(head, node, NULL, 0)
struct bpf_list_node *bpf_list_pop_front(struct bpf_list_head *head) __ksym;
struct bpf_list_node *bpf_list_pop_back(struct bpf_list_head *head) __ksym;
struct bpf_rb_node *bpf_rbtree_remove(struct bpf_rb_root *root,
struct bpf_rb_node *node) __ksym;
int bpf_rbtree_add_impl(struct bpf_rb_root *root, struct bpf_rb_node *node,
bool (less)(struct bpf_rb_node *a, const struct bpf_rb_node *b),
void *meta, __u64 off) __ksym;
#define bpf_rbtree_add(head, node, less) bpf_rbtree_add_impl(head, node, less, NULL, 0)
struct bpf_rb_node *bpf_rbtree_first(struct bpf_rb_root *root) __ksym;
void *bpf_refcount_acquire_impl(void *kptr, void *meta) __ksym;
#define bpf_refcount_acquire(kptr) bpf_refcount_acquire_impl(kptr, NULL)
/* task */
struct task_struct *bpf_task_from_pid(s32 pid) __ksym;
struct task_struct *bpf_task_acquire(struct task_struct *p) __ksym;
void bpf_task_release(struct task_struct *p) __ksym;
/* cgroup */
struct cgroup *bpf_cgroup_ancestor(struct cgroup *cgrp, int level) __ksym;
struct cgroup *bpf_cgroup_acquire(struct cgroup *cgrp) __ksym;
void bpf_cgroup_release(struct cgroup *cgrp) __ksym;
struct cgroup *bpf_cgroup_from_id(u64 cgid) __ksym;
/* css iteration */
struct bpf_iter_css;
struct cgroup_subsys_state;
extern int bpf_iter_css_new(struct bpf_iter_css *it,
struct cgroup_subsys_state *start,
unsigned int flags) __weak __ksym;
extern struct cgroup_subsys_state *
bpf_iter_css_next(struct bpf_iter_css *it) __weak __ksym;
extern void bpf_iter_css_destroy(struct bpf_iter_css *it) __weak __ksym;
/* cpumask */
struct bpf_cpumask *bpf_cpumask_create(void) __ksym;
struct bpf_cpumask *bpf_cpumask_acquire(struct bpf_cpumask *cpumask) __ksym;
void bpf_cpumask_release(struct bpf_cpumask *cpumask) __ksym;
u32 bpf_cpumask_first(const struct cpumask *cpumask) __ksym;
u32 bpf_cpumask_first_zero(const struct cpumask *cpumask) __ksym;
void bpf_cpumask_set_cpu(u32 cpu, struct bpf_cpumask *cpumask) __ksym;
void bpf_cpumask_clear_cpu(u32 cpu, struct bpf_cpumask *cpumask) __ksym;
bool bpf_cpumask_test_cpu(u32 cpu, const struct cpumask *cpumask) __ksym;
bool bpf_cpumask_test_and_set_cpu(u32 cpu, struct bpf_cpumask *cpumask) __ksym;
bool bpf_cpumask_test_and_clear_cpu(u32 cpu, struct bpf_cpumask *cpumask) __ksym;
void bpf_cpumask_setall(struct bpf_cpumask *cpumask) __ksym;
void bpf_cpumask_clear(struct bpf_cpumask *cpumask) __ksym;
bool bpf_cpumask_and(struct bpf_cpumask *dst, const struct cpumask *src1,
const struct cpumask *src2) __ksym;
void bpf_cpumask_or(struct bpf_cpumask *dst, const struct cpumask *src1,
const struct cpumask *src2) __ksym;
void bpf_cpumask_xor(struct bpf_cpumask *dst, const struct cpumask *src1,
const struct cpumask *src2) __ksym;
bool bpf_cpumask_equal(const struct cpumask *src1, const struct cpumask *src2) __ksym;
bool bpf_cpumask_intersects(const struct cpumask *src1, const struct cpumask *src2) __ksym;
bool bpf_cpumask_subset(const struct cpumask *src1, const struct cpumask *src2) __ksym;
bool bpf_cpumask_empty(const struct cpumask *cpumask) __ksym;
bool bpf_cpumask_full(const struct cpumask *cpumask) __ksym;
void bpf_cpumask_copy(struct bpf_cpumask *dst, const struct cpumask *src) __ksym;
u32 bpf_cpumask_any_distribute(const struct cpumask *cpumask) __ksym;
u32 bpf_cpumask_any_and_distribute(const struct cpumask *src1,
const struct cpumask *src2) __ksym;
u32 bpf_cpumask_weight(const struct cpumask *cpumask) __ksym;
int bpf_iter_bits_new(struct bpf_iter_bits *it, const u64 *unsafe_ptr__ign, u32 nr_words) __ksym;
int *bpf_iter_bits_next(struct bpf_iter_bits *it) __ksym;
void bpf_iter_bits_destroy(struct bpf_iter_bits *it) __ksym;
#define def_iter_struct(name) \
struct bpf_iter_##name { \
struct bpf_iter_bits it; \
const struct cpumask *bitmap; \
};
#define def_iter_new(name) \
static inline int bpf_iter_##name##_new( \
struct bpf_iter_##name *it, const u64 *unsafe_ptr__ign, u32 nr_words) \
{ \
it->bitmap = scx_bpf_get_##name##_cpumask(); \
return bpf_iter_bits_new(&it->it, (const u64 *)it->bitmap, \
sizeof(struct cpumask) / 8); \
}
#define def_iter_next(name) \
static inline int *bpf_iter_##name##_next(struct bpf_iter_##name *it) { \
return bpf_iter_bits_next(&it->it); \
}
#define def_iter_destroy(name) \
static inline void bpf_iter_##name##_destroy(struct bpf_iter_##name *it) { \
scx_bpf_put_cpumask(it->bitmap); \
bpf_iter_bits_destroy(&it->it); \
}
#define def_for_each_cpu(cpu, name) for_each_##name##_cpu(cpu)
/// Provides iterator for possible and online cpus.
///
/// # Example
///
/// ```
/// static inline void example_use() {
/// int *cpu;
///
/// for_each_possible_cpu(cpu){
/// bpf_printk("CPU %d is possible", *cpu);
/// }
///
/// for_each_online_cpu(cpu){
/// bpf_printk("CPU %d is online", *cpu);
/// }
/// }
/// ```
def_iter_struct(possible);
def_iter_new(possible);
def_iter_next(possible);
def_iter_destroy(possible);
#define for_each_possible_cpu(cpu) bpf_for_each(possible, cpu, NULL, 0)
def_iter_struct(online);
def_iter_new(online);
def_iter_next(online);
def_iter_destroy(online);
#define for_each_online_cpu(cpu) bpf_for_each(online, cpu, NULL, 0)
/*
* Access a cpumask in read-only mode (typically to check bits).
*/
static __always_inline const struct cpumask *cast_mask(struct bpf_cpumask *mask)
{
return (const struct cpumask *)mask;
}
/*
* Return true if task @p cannot migrate to a different CPU, false
* otherwise.
*/
static inline bool is_migration_disabled(const struct task_struct *p)
{
/*
* Testing p->migration_disabled in a BPF code is tricky because the
* migration is _always_ disabled while running the BPF code.
* The prolog (__bpf_prog_enter) and epilog (__bpf_prog_exit) for BPF
* code execution disable and re-enable the migration of the current
* task, respectively. So, the _current_ task of the sched_ext ops is
* always migration-disabled. Moreover, p->migration_disabled could be
* two or greater when a sched_ext ops BPF code (e.g., ops.tick) is
* executed in the middle of the other BPF code execution.
*
* Therefore, we should decide that the _current_ task is
* migration-disabled only when its migration_disabled count is greater
* than one. In other words, when p->migration_disabled == 1, there is
* an ambiguity, so we should check if @p is the current task or not.
*/
if (bpf_core_field_exists(p->migration_disabled)) {
if (p->migration_disabled == 1)
return bpf_get_current_task_btf() != p;
else
return p->migration_disabled;
}
return false;
}
/* rcu */
void bpf_rcu_read_lock(void) __ksym;
void bpf_rcu_read_unlock(void) __ksym;
/* resilient qspinlock */
int bpf_res_spin_lock(struct bpf_res_spin_lock *lock) __ksym __weak;
void bpf_res_spin_unlock(struct bpf_res_spin_lock *lock) __ksym __weak;
/*
* Time helpers, most of which are from jiffies.h.
*/
/**
* time_delta - Calculate the delta between new and old time stamp
* @after: first comparable as u64
* @before: second comparable as u64
*
* Return: the time difference, which is >= 0
*/
static inline s64 time_delta(u64 after, u64 before)
{
return (s64)(after - before) > 0 ? (s64)(after - before) : 0;
}
/**
* time_after - returns true if the time a is after time b.
* @a: first comparable as u64
* @b: second comparable as u64
*
* Do this with "<0" and ">=0" to only test the sign of the result. A
* good compiler would generate better code (and a really good compiler
* wouldn't care). Gcc is currently neither.
*
* Return: %true is time a is after time b, otherwise %false.
*/
static inline bool time_after(u64 a, u64 b)
{
return (s64)(b - a) < 0;
}
/**
* time_before - returns true if the time a is before time b.
* @a: first comparable as u64
* @b: second comparable as u64
*
* Return: %true is time a is before time b, otherwise %false.
*/
static inline bool time_before(u64 a, u64 b)
{
return time_after(b, a);
}
/**
* time_after_eq - returns true if the time a is after or the same as time b.
* @a: first comparable as u64
* @b: second comparable as u64
*
* Return: %true is time a is after or the same as time b, otherwise %false.
*/
static inline bool time_after_eq(u64 a, u64 b)
{
return (s64)(a - b) >= 0;
}
/**
* time_before_eq - returns true if the time a is before or the same as time b.
* @a: first comparable as u64
* @b: second comparable as u64
*
* Return: %true is time a is before or the same as time b, otherwise %false.
*/
static inline bool time_before_eq(u64 a, u64 b)
{
return time_after_eq(b, a);
}
/**
* time_in_range - Calculate whether a is in the range of [b, c].
* @a: time to test
* @b: beginning of the range
* @c: end of the range
*
* Return: %true is time a is in the range [b, c], otherwise %false.
*/
static inline bool time_in_range(u64 a, u64 b, u64 c)
{
return time_after_eq(a, b) && time_before_eq(a, c);
}
/**
* time_in_range_open - Calculate whether a is in the range of [b, c).
* @a: time to test
* @b: beginning of the range
* @c: end of the range
*
* Return: %true is time a is in the range [b, c), otherwise %false.
*/
static inline bool time_in_range_open(u64 a, u64 b, u64 c)
{
return time_after_eq(a, b) && time_before(a, c);
}
/*
* Other helpers
*/
/* useful compiler attributes */
#ifndef likely
#define likely(x) __builtin_expect(!!(x), 1)
#endif
#ifndef unlikely
#define unlikely(x) __builtin_expect(!!(x), 0)
#endif
#ifndef __maybe_unused
#define __maybe_unused __attribute__((__unused__))
#endif
/*
* READ/WRITE_ONCE() are from kernel (include/asm-generic/rwonce.h). They
* prevent compiler from caching, redoing or reordering reads or writes.
*/
typedef __u8 __attribute__((__may_alias__)) __u8_alias_t;
typedef __u16 __attribute__((__may_alias__)) __u16_alias_t;
typedef __u32 __attribute__((__may_alias__)) __u32_alias_t;
typedef __u64 __attribute__((__may_alias__)) __u64_alias_t;
static __always_inline void __read_once_size(const volatile void *p, void *res, int size)
{
switch (size) {
case 1: *(__u8_alias_t *) res = *(volatile __u8_alias_t *) p; break;
case 2: *(__u16_alias_t *) res = *(volatile __u16_alias_t *) p; break;
case 4: *(__u32_alias_t *) res = *(volatile __u32_alias_t *) p; break;
case 8: *(__u64_alias_t *) res = *(volatile __u64_alias_t *) p; break;
default:
barrier();
__builtin_memcpy((void *)res, (const void *)p, size);
barrier();
}
}
static __always_inline void __write_once_size(volatile void *p, void *res, int size)
{
switch (size) {
case 1: *(volatile __u8_alias_t *) p = *(__u8_alias_t *) res; break;
case 2: *(volatile __u16_alias_t *) p = *(__u16_alias_t *) res; break;
case 4: *(volatile __u32_alias_t *) p = *(__u32_alias_t *) res; break;
case 8: *(volatile __u64_alias_t *) p = *(__u64_alias_t *) res; break;
default:
barrier();
__builtin_memcpy((void *)p, (const void *)res, size);
barrier();
}
}
/*
* __unqual_typeof(x) - Declare an unqualified scalar type, leaving
* non-scalar types unchanged,
*
* Prefer C11 _Generic for better compile-times and simpler code. Note: 'char'
* is not type-compatible with 'signed char', and we define a separate case.
*
* This is copied verbatim from kernel's include/linux/compiler_types.h, but
* with default expression (for pointers) changed from (x) to (typeof(x)0).
*
* This is because LLVM has a bug where for lvalue (x), it does not get rid of
* an extra address_space qualifier, but does in case of rvalue (typeof(x)0).
* Hence, for pointers, we need to create an rvalue expression to get the
* desired type. See https://github.com/llvm/llvm-project/issues/53400.
*/
#define __scalar_type_to_expr_cases(type) \
unsigned type : (unsigned type)0, signed type : (signed type)0
#define __unqual_typeof(x) \
typeof(_Generic((x), \
char: (char)0, \
__scalar_type_to_expr_cases(char), \
__scalar_type_to_expr_cases(short), \
__scalar_type_to_expr_cases(int), \
__scalar_type_to_expr_cases(long), \
__scalar_type_to_expr_cases(long long), \
default: (typeof(x))0))
#define READ_ONCE(x) \
({ \
union { __unqual_typeof(x) __val; char __c[1]; } __u = \
{ .__c = { 0 } }; \
__read_once_size((__unqual_typeof(x) *)&(x), __u.__c, sizeof(x)); \
__u.__val; \
})
#define WRITE_ONCE(x, val) \
({ \
union { __unqual_typeof(x) __val; char __c[1]; } __u = \
{ .__val = (val) }; \
__write_once_size((__unqual_typeof(x) *)&(x), __u.__c, sizeof(x)); \
__u.__val; \
})
/*
* __calc_avg - Calculate exponential weighted moving average (EWMA) with
* @old and @new values. @decay represents how large the @old value remains.
* With a larger @decay value, the moving average changes slowly, exhibiting
* fewer fluctuations.
*/
#define __calc_avg(old, new, decay) ({ \
typeof(decay) thr = 1 << (decay); \
typeof(old) ret; \
if (((old) < thr) || ((new) < thr)) { \
if (((old) == 1) && ((new) == 0)) \
ret = 0; \
else \
ret = ((old) - ((old) >> 1)) + ((new) >> 1); \
} else { \
ret = ((old) - ((old) >> (decay))) + ((new) >> (decay)); \
} \
ret; \
})
/*
* log2_u32 - Compute the base 2 logarithm of a 32-bit exponential value.
* @v: The value for which we're computing the base 2 logarithm.
*/
static inline u32 log2_u32(u32 v)
{
u32 r;
u32 shift;
r = (v > 0xFFFF) << 4; v >>= r;
shift = (v > 0xFF) << 3; v >>= shift; r |= shift;
shift = (v > 0xF) << 2; v >>= shift; r |= shift;
shift = (v > 0x3) << 1; v >>= shift; r |= shift;
r |= (v >> 1);
return r;
}
/*
* log2_u64 - Compute the base 2 logarithm of a 64-bit exponential value.
* @v: The value for which we're computing the base 2 logarithm.
*/
static inline u32 log2_u64(u64 v)
{
u32 hi = v >> 32;
if (hi)
return log2_u32(hi) + 32 + 1;
else
return log2_u32(v) + 1;
}
/*
* sqrt_u64 - Calculate the square root of value @x using Newton's method.
*/
static inline u64 __sqrt_u64(u64 x)
{
if (x == 0 || x == 1)
return x;
u64 r = ((1ULL << 32) > x) ? x : (1ULL << 32);
for (int i = 0; i < 8; ++i) {
u64 q = x / r;
if (r <= q)
break;
r = (r + q) >> 1;
}
return r;
}
/*
* ctzll -- Counts trailing zeros in an unsigned long long. If the input value
* is zero, the return value is undefined.
*/
static inline int ctzll(u64 v)
{
#if (!defined(__BPF__) && defined(__SCX_TARGET_ARCH_x86)) || \
(defined(__BPF__) && defined(__clang_major__) && __clang_major__ >= 19)
/*
* Use the ctz builtin when: (1) building for native x86, or
* (2) building for BPF with clang >= 19 (BPF backend supports
* the intrinsic from clang 19 onward; earlier versions hit
* "unimplemented opcode" in the backend).
*/
return __builtin_ctzll(v);
#else
/*
* If neither the target architecture nor the toolchains support ctzll,
* use software-based emulation. Let's use the De Bruijn sequence-based
* approach to find LSB fastly. See the details of De Bruijn sequence:
*
* https://en.wikipedia.org/wiki/De_Bruijn_sequence
* https://www.chessprogramming.org/BitScan#De_Bruijn_Multiplication
*/
const int lookup_table[64] = {
0, 1, 48, 2, 57, 49, 28, 3, 61, 58, 50, 42, 38, 29, 17, 4,
62, 55, 59, 36, 53, 51, 43, 22, 45, 39, 33, 30, 24, 18, 12, 5,
63, 47, 56, 27, 60, 41, 37, 16, 54, 35, 52, 21, 44, 32, 23, 11,
46, 26, 40, 15, 34, 20, 31, 10, 25, 14, 19, 9, 13, 8, 7, 6,
};
const u64 DEBRUIJN_CONSTANT = 0x03f79d71b4cb0a89ULL;
unsigned int index;
u64 lowest_bit;
const int *lt;
if (v == 0)
return -1;
/*
* Isolate the least significant bit (LSB).
* For example, if v = 0b...10100, then v & -v = 0b...00100
*/
lowest_bit = v & -v;
/*
* Each isolated bit produces a unique 6-bit value, guaranteed by the
* De Bruijn property. Calculate a unique index into the lookup table
* using the magic constant and a right shift.
*
* Multiplying by the 64-bit constant "spreads out" that 1-bit into a
* unique pattern in the top 6 bits. This uniqueness property is
* exactly what a De Bruijn sequence guarantees: Every possible 6-bit
* pattern (in top bits) occurs exactly once for each LSB position. So,
* the constant 0x03f79d71b4cb0a89ULL is carefully chosen to be a
* De Bruijn sequence, ensuring no collisions in the table index.
*/
index = (lowest_bit * DEBRUIJN_CONSTANT) >> 58;
/*
* Lookup in a precomputed table. No collision is guaranteed by the
* De Bruijn property.
*/
lt = MEMBER_VPTR(lookup_table, [index]);
return (lt)? *lt : -1;
#endif
}
/*
* Return a value proportionally scaled to the task's weight.
*/
static inline u64 scale_by_task_weight(const struct task_struct *p, u64 value)
{
return (value * p->scx.weight) / 100;
}
/*
* Return a value inversely proportional to the task's weight.
*/
static inline u64 scale_by_task_weight_inverse(const struct task_struct *p, u64 value)
{
return value * 100 / p->scx.weight;
}
/*
* Get a random u64 from the kernel's pseudo-random generator.
*/
static inline u64 get_prandom_u64()
{
return ((u64)bpf_get_prandom_u32() << 32) | bpf_get_prandom_u32();
}
/*
* Define the shadow structure to avoid a compilation error when
* vmlinux.h does not enable necessary kernel configs. The ___local
* suffix is a CO-RE convention that tells the loader to match this
* against the base struct rq in the kernel. The attribute
* preserve_access_index tells the compiler to generate a CO-RE
* relocation for these fields.
*/
struct rq___local {
/*
* A monotonically increasing clock per CPU. It is rq->clock minus
* cumulative IRQ time and hypervisor steal time. Unlike rq->clock,
* it does not advance during IRQ processing or hypervisor preemption.
* It does advance during idle (the idle task counts as a running task
* for this purpose).
*/
u64 clock_task;
/*
* Invariant version of clock_task scaled by CPU capacity and
* frequency. For example, clock_pelt advances 2x slower on a CPU
* with half the capacity.
*
* At idle exit, rq->clock_pelt jumps forward to resync with
* clock_task. The kernel's rq_clock_pelt() corrects for this jump
* by subtracting lost_idle_time, yielding a clock that appears
* continuous across idle transitions. scx_clock_pelt() mirrors
* rq_clock_pelt() by performing the same subtraction.
*/
u64 clock_pelt;
/*
* Accumulates the magnitude of each clock_pelt jump at idle exit.
* Subtracting this from clock_pelt gives rq_clock_pelt(): a
* continuous, capacity-invariant clock suitable for both task
* execution time stamping and cross-idle measurements.
*/
unsigned long lost_idle_time;
/*
* Shadow of paravirt_steal_clock() (the hypervisor's cumulative
* stolen time counter). Stays frozen while the hypervisor preempts
* the vCPU; catches up the next time update_rq_clock_task() is
* called. The delta is the stolen time not yet subtracted from
* clock_task.
*
* Unlike irqtime->total (a plain kernel-side field), the live stolen
* time counter lives in hypervisor-specific shared memory and has no
* kernel-side equivalent readable from BPF in a hypervisor-agnostic
* way. This field is therefore the only portable BPF-accessible
* approximation of cumulative steal time.
*
* Available only when CONFIG_PARAVIRT_TIME_ACCOUNTING is on.
*/
u64 prev_steal_time_rq;
} __attribute__((preserve_access_index));
extern struct rq runqueues __ksym;
/*
* Define the shadow structure to avoid a compilation error when
* vmlinux.h does not enable necessary kernel configs.
*/
struct irqtime___local {
/*
* Cumulative IRQ time counter for this CPU, in nanoseconds. Advances
* immediately at the exit of every hardirq and non-ksoftirqd softirq
* via irqtime_account_irq(). ksoftirqd time is counted as normal
* task time and is NOT included. NMI time is also NOT included.
*
* The companion field irqtime->sync (struct u64_stats_sync) protects
* against 64-bit tearing on 32-bit architectures. On 64-bit kernels,
* u64_stats_sync is an empty struct and all seqcount operations are
* no-ops, so a plain BPF_CORE_READ of this field is safe.
*
* Available only when CONFIG_IRQ_TIME_ACCOUNTING is on.
*/
u64 total;
} __attribute__((preserve_access_index));
/*
* cpu_irqtime is a per-CPU variable defined only when
* CONFIG_IRQ_TIME_ACCOUNTING is on. Declare it as __weak so the BPF
* loader sets its address to 0 (rather than failing) when the symbol
* is absent from the running kernel.
*/
extern struct irqtime___local cpu_irqtime __ksym __weak;
static inline struct rq___local *get_current_rq(u32 cpu)
{
/*
* This is a workaround to get an rq pointer now that
* scx_bpf_cpu_rq() has been removed.
*
* WARNING: The caller must hold the rq lock for @cpu. This is
* guaranteed when called from scheduling callbacks (ops.running,
* ops.stopping, ops.enqueue, ops.dequeue, ops.dispatch, etc.).
* There is no runtime check available in BPF for kernel spinlock
* state — correctness is enforced by calling context only.
*/
return (void *)bpf_per_cpu_ptr(&runqueues, cpu);
}
static inline u64 scx_clock_task(u32 cpu)
{
struct rq___local *rq = get_current_rq(cpu);
/* Equivalent to the kernel's rq_clock_task(). */
return rq ? rq->clock_task : 0;
}
static inline u64 scx_clock_pelt(u32 cpu)
{
struct rq___local *rq = get_current_rq(cpu);
/*
* Equivalent to the kernel's rq_clock_pelt(): subtracts
* lost_idle_time from clock_pelt to absorb the jump that occurs
* when clock_pelt resyncs with clock_task at idle exit. The result
* is a continuous, capacity-invariant clock safe for both task
* execution time stamping and cross-idle measurements.
*/
return rq ? (rq->clock_pelt - rq->lost_idle_time) : 0;
}
static inline u64 scx_clock_virt(u32 cpu)
{
struct rq___local *rq;
/*
* Check field existence before calling get_current_rq() so we avoid
* the per_cpu lookup entirely on kernels built without
* CONFIG_PARAVIRT_TIME_ACCOUNTING.
*/
if (!bpf_core_field_exists(((struct rq___local *)0)->prev_steal_time_rq))
return 0;
/* Lagging shadow of the kernel's paravirt_steal_clock(). */
rq = get_current_rq(cpu);
return rq ? BPF_CORE_READ(rq, prev_steal_time_rq) : 0;
}
static inline u64 scx_clock_irq(u32 cpu)
{
struct irqtime___local *irqt;
/*
* bpf_core_type_exists() resolves at load time: if struct irqtime is
* absent from kernel BTF (CONFIG_IRQ_TIME_ACCOUNTING off), the loader
* patches this into an unconditional return 0, making the
* bpf_per_cpu_ptr() call below dead code that the verifier never sees.
*/
if (!bpf_core_type_exists(struct irqtime___local))
return 0;
/* Equivalent to the kernel's irq_time_read(). */
irqt = bpf_per_cpu_ptr(&cpu_irqtime, cpu);
return irqt ? BPF_CORE_READ(irqt, total) : 0;
}
/* Abbreviated forms of <linux/overflow.h>'s struct_size() family. */
#define flex_array_size(p, member, count) \
((count) * sizeof(*(p)->member))
#define struct_size(p, member, count) \
(offsetof(typeof(*(p)), member) + flex_array_size(p, member, count))
#define struct_size_t(type, member, count) \
struct_size((type *)NULL, member, count)
#include "compat.bpf.h"
#include "enums.bpf.h"
#include "cid.bpf.h"
#endif /* __SCX_COMMON_BPF_H */
