1 files changed, 67 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/bpf_arena_alloc.h b/tools/testing/selftests/bpf/bpf_arena_alloc.h
new file mode 100644
index 000000000000..c27678299e0c
--- /dev/null
+++ b/tools/testing/selftests/bpf/bpf_arena_alloc.h
@@ -0,0 +1,67 @@
+/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
+/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */
+#pragma once
+#include "bpf_arena_common.h"
+
+#ifndef __round_mask
+#define __round_mask(x, y) ((__typeof__(x))((y)-1))
+#endif
+#ifndef round_up
+#define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
+#endif
+
+#ifdef __BPF__
+#define NR_CPUS (sizeof(struct cpumask) * 8)
+
+static void __arena * __arena page_frag_cur_page[NR_CPUS];
+static int __arena page_frag_cur_offset[NR_CPUS];
+
+/* Simple page_frag allocator */
+static inline void __arena* bpf_alloc(unsigned int size)
+{
+	__u64 __arena *obj_cnt;
+	__u32 cpu = bpf_get_smp_processor_id();
+	void __arena *page = page_frag_cur_page[cpu];
+	int __arena *cur_offset = &page_frag_cur_offset[cpu];
+	int offset;
+
+	size = round_up(size, 8);
+	if (size >= PAGE_SIZE - 8)
+		return NULL;
+	if (!page) {
+refill:
+		page = bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);
+		if (!page)
+			return NULL;
+		cast_kern(page);
+		page_frag_cur_page[cpu] = page;
+		*cur_offset = PAGE_SIZE - 8;
+		obj_cnt = page + PAGE_SIZE - 8;
+		*obj_cnt = 0;
+	} else {
+		cast_kern(page);
+		obj_cnt = page + PAGE_SIZE - 8;
+	}
+
+	offset = *cur_offset - size;
+	if (offset < 0)
+		goto refill;
+
+	(*obj_cnt)++;
+	*cur_offset = offset;
+	return page + offset;
+}
+
+static inline void bpf_free(void __arena *addr)
+{
+	__u64 __arena *obj_cnt;
+
+	addr = (void __arena *)(((long)addr) & ~(PAGE_SIZE - 1));
+	obj_cnt = addr + PAGE_SIZE - 8;
+	if (--(*obj_cnt) == 0)
+		bpf_arena_free_pages(&arena, addr, 1);
+}
+#else
+static inline void __arena* bpf_alloc(unsigned int size) { return NULL; }
+static inline void bpf_free(void __arena *addr) {}
+#endif