/* SPDX-License-Identifier: GPL-2.0 */
/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */

#ifndef _CPUMASK_COMMON_H
#define _CPUMASK_COMMON_H

#include "errno.h"
#include <stdbool.h>

/* Should use BTF_FIELDS_MAX, but it is not always available in vmlinux.h,
 * so use the hard-coded number as a workaround.
 */
#define CPUMASK_KPTR_FIELDS_MAX 11

int err;

#define private(name) SEC(".bss." #name) __attribute__((aligned(8)))
private(MASK) static struct bpf_cpumask __kptr * global_mask;

struct __cpumask_map_value {
        struct bpf_cpumask __kptr * cpumask;
};

struct array_map {
        __uint(type, BPF_MAP_TYPE_ARRAY);
        __type(key, int);
        __type(value, struct __cpumask_map_value);
        __uint(max_entries, 1);
} __cpumask_map SEC(".maps");

struct bpf_cpumask *bpf_cpumask_create(void) __ksym __weak;
void bpf_cpumask_release(struct bpf_cpumask *cpumask) __ksym __weak;
struct bpf_cpumask *bpf_cpumask_acquire(struct bpf_cpumask *cpumask) __ksym __weak;
u32 bpf_cpumask_first(const struct cpumask *cpumask) __ksym __weak;
u32 bpf_cpumask_first_zero(const struct cpumask *cpumask) __ksym __weak;
u32 bpf_cpumask_first_and(const struct cpumask *src1,
                          const struct cpumask *src2) __ksym __weak;
void bpf_cpumask_set_cpu(u32 cpu, struct bpf_cpumask *cpumask) __ksym __weak;
void bpf_cpumask_clear_cpu(u32 cpu, struct bpf_cpumask *cpumask) __ksym __weak;
bool bpf_cpumask_test_cpu(u32 cpu, const struct cpumask *cpumask) __ksym __weak;
bool bpf_cpumask_test_and_set_cpu(u32 cpu, struct bpf_cpumask *cpumask) __ksym __weak;
bool bpf_cpumask_test_and_clear_cpu(u32 cpu, struct bpf_cpumask *cpumask) __ksym __weak;
void bpf_cpumask_setall(struct bpf_cpumask *cpumask) __ksym __weak;
void bpf_cpumask_clear(struct bpf_cpumask *cpumask) __ksym __weak;
bool bpf_cpumask_and(struct bpf_cpumask *cpumask,
                     const struct cpumask *src1,
                     const struct cpumask *src2) __ksym __weak;
void bpf_cpumask_or(struct bpf_cpumask *cpumask,
                    const struct cpumask *src1,
                    const struct cpumask *src2) __ksym __weak;
void bpf_cpumask_xor(struct bpf_cpumask *cpumask,
                     const struct cpumask *src1,
                     const struct cpumask *src2) __ksym __weak;
bool bpf_cpumask_equal(const struct cpumask *src1, const struct cpumask *src2) __ksym __weak;
bool bpf_cpumask_intersects(const struct cpumask *src1, const struct cpumask *src2) __ksym __weak;
bool bpf_cpumask_subset(const struct cpumask *src1, const struct cpumask *src2) __ksym __weak;
bool bpf_cpumask_empty(const struct cpumask *cpumask) __ksym __weak;
bool bpf_cpumask_full(const struct cpumask *cpumask) __ksym __weak;
void bpf_cpumask_copy(struct bpf_cpumask *dst, const struct cpumask *src) __ksym __weak;
u32 bpf_cpumask_any_distribute(const struct cpumask *src) __ksym __weak;
u32 bpf_cpumask_any_and_distribute(const struct cpumask *src1,
                                   const struct cpumask *src2) __ksym __weak;
u32 bpf_cpumask_weight(const struct cpumask *cpumask) __ksym __weak;
int bpf_cpumask_populate(struct cpumask *cpumask, void *src, size_t src__sz) __ksym __weak;

void bpf_rcu_read_lock(void) __ksym __weak;
void bpf_rcu_read_unlock(void) __ksym __weak;

static inline const struct cpumask *cast(struct bpf_cpumask *cpumask)
{
        return (const struct cpumask *)cpumask;
}

static inline struct bpf_cpumask *create_cpumask(void)
{
        struct bpf_cpumask *cpumask;

        cpumask = bpf_cpumask_create();
        if (!cpumask) {
                err = 1;
                return NULL;
        }

        if (!bpf_cpumask_empty(cast(cpumask))) {
                err = 2;
                bpf_cpumask_release(cpumask);
                return NULL;
        }

        return cpumask;
}

static inline struct __cpumask_map_value *cpumask_map_value_lookup(void)
{
        u32 key = 0;

        return bpf_map_lookup_elem(&__cpumask_map, &key);
}

static inline int cpumask_map_insert(struct bpf_cpumask *mask)
{
        struct __cpumask_map_value local, *v;
        long status;
        struct bpf_cpumask *old;
        u32 key = 0;

        local.cpumask = NULL;
        status = bpf_map_update_elem(&__cpumask_map, &key, &local, 0);
        if (status) {
                bpf_cpumask_release(mask);
                return status;
        }

        v = bpf_map_lookup_elem(&__cpumask_map, &key);
        if (!v) {
                bpf_cpumask_release(mask);
                return -ENOENT;
        }

        old = bpf_kptr_xchg(&v->cpumask, mask);
        if (old) {
                bpf_cpumask_release(old);
                return -EEXIST;
        }

        return 0;
}

#endif /* _CPUMASK_COMMON_H */