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// SPDX-License-Identifier: LGPL-2.1 OR BSD-2-Clause
/* Copyright (c) 2026 Meta Platforms, Inc. and affiliates. */
#include <limits.h>
#include <libarena/common.h>
#include <libarena/asan.h>
#include <libarena/buddy.h>
struct buddy __arena buddy;
volatile u32 zero = 0;
/*
* Storage for the queue nodes declared by bpf_arena_spin_lock.h. Each program
* linking the arena spinlock provides exactly one definition, so that the array
* is emitted once rather than once per translation unit.
*/
struct arena_qnode __arena __hidden qnodes[_Q_MAX_CPUS][_Q_MAX_NODES];
int arena_fls(__u64 word)
{
if (!word)
return 0;
return 64 - __builtin_clzll(word);
}
SEC("syscall")
__weak int arena_get_info(struct arena_get_info_args *args)
{
args->arena_base = arena_base(&arena);
return 0;
}
SEC("syscall")
__weak int arena_alloc_reserve(struct arena_alloc_reserve_args *args)
{
return bpf_arena_reserve_pages(&arena, NULL, args->nr_pages);
}
SEC("syscall")
__weak int arena_buddy_reset(void)
{
buddy_destroy(&buddy);
return buddy_init(&buddy);
}
SEC("syscall")
__weak int arena_buddy_destroy(void)
{
return buddy_destroy(&buddy);
}
__weak void __arena *arena_malloc(size_t size)
{
return buddy_alloc(&buddy, size);
}
__weak void __arena *arena_calloc(size_t ncount, size_t size)
{
void __arena *mem;
size_t total;
/*
* Ideally we'd be using __builtin_mul_overflow here,
* but the BPF compiler backend doesn't implement __multi3.
* There are ways to optimize the division away from the
* overflow check, but any costs are dwarfed by the
* buddy_alloc() call. Keep it simple for now.
*/
if (unlikely(ncount && size >= ULLONG_MAX / ncount))
return NULL;
total = ncount * size;
mem = buddy_alloc(&buddy, total);
if (likely(mem))
arena_memset(mem, 0, total);
return mem;
}
__weak void arena_free(void __arena *ptr)
{
buddy_free(&buddy, ptr);
}
char _license[] SEC("license") = "GPL";
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