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// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2026 Meta Platforms, Inc. and affiliates. */
#define BPF_NO_KFUNC_PROTOTYPES
#include <vmlinux.h>
#include <bpf/bpf_helpers.h>
#include "bpf_misc.h"
#include "bpf_experimental.h"
#include <bpf_arena_common.h>
#include "../test_kmods/bpf_testmod_kfunc.h"
struct {
__uint(type, BPF_MAP_TYPE_ARENA);
__uint(map_flags, BPF_F_MMAPABLE);
/* page 0 hosts the arena global, page 1 is for allocations */
__uint(max_entries, 2);
} arena SEC(".maps");
/*
* Occupies page 0 so no allocation lands at arena offset 0, which the
* nullable tests below must be able to tell apart from NULL.
*/
u64 __arena arena_pad;
/* volatile to force the scalar reloads below */
volatile u64 stash;
SEC("syscall")
__arch_x86_64
__arch_arm64
__success __retval(0)
int arena_arg_forms(void *ctx)
{
#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
u64 __arena *val;
u64 ret;
val = bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);
if (!val)
return 1;
/* PTR_TO_ARENA argument */
*val = 41;
ret = bpf_kfunc_arena_arg_test((u64 *)val);
if (ret != 41 || *val != 42)
return 2;
/* the low 32 bits as a scalar */
stash = (u32)(u64)val;
ret = bpf_kfunc_arena_arg_test((u64 *)stash);
if (ret != 42 || *val != 43)
return 3;
/* the full user address as a scalar */
stash = (u64)val;
bpf_addr_space_cast(stash, 1, 0);
ret = bpf_kfunc_arena_arg_test((u64 *)stash);
if (ret != 43 || *val != 44)
return 4;
bpf_arena_free_pages(&arena, (void __arena *)val, 1);
#endif
return 0;
}
/*
* Pin the rebase semantics using the capture kfuncs, which return the raw
* argument value: __arena rebases unconditionally, so zero low 32 bits
* arrive as the arena kernel base, while __arena__nullable turns them into
* NULL.
*/
SEC("syscall")
__arch_x86_64
__arch_arm64
__success __retval(0)
int arena_arg_rebase(void *ctx)
{
#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
u64 __arena *val;
u64 base, off;
val = bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);
if (!val)
return 1;
base = bpf_kfunc_arena_cap_test(NULL);
if (!base)
return 2;
/* only the low 32 bits contribute */
stash = 0xbadc0ffe00000000;
if (bpf_kfunc_arena_cap_test((u64 *)stash) != base)
return 3;
off = (u32)(u64)val;
if (bpf_kfunc_arena_cap_test((u64 *)val) != base + off)
return 4;
if (bpf_kfunc_arena_cap_nullable_test(NULL) != 0)
return 5;
stash = 0xbadc0ffe00000000;
if (bpf_kfunc_arena_cap_nullable_test((u64 *)stash) != 0)
return 6;
if (bpf_kfunc_arena_cap_nullable_test((u64 *)val) != base + off)
return 7;
bpf_arena_free_pages(&arena, (void __arena *)val, 1);
#endif
return 0;
}
SEC("syscall")
__arch_x86_64
__arch_arm64
__success __retval(0)
int arena_args5(void *ctx)
{
#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
u64 __arena *val;
val = bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);
if (!val)
return 1;
val[0] = 1;
val[1] = 2;
val[2] = 4;
val[3] = 8;
val[4] = 16;
if (bpf_kfunc_arena_args5_test((u64 *)&val[0], (u64 *)&val[1],
(u64 *)&val[2], (u64 *)&val[3],
(u64 *)&val[4]) != 31)
return 2;
if (bpf_kfunc_arena_args5_test((u64 *)&val[0], (u64 *)&val[1],
(u64 *)&val[2], (u64 *)&val[3], NULL) != 15)
return 3;
bpf_arena_free_pages(&arena, (void __arena *)val, 1);
#endif
return 0;
}
SEC("syscall")
__arch_x86_64
__arch_arm64
__success __retval(0)
int arena_arg_mixed(void *ctx)
{
#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
u64 __arena *val;
val = bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);
if (!val)
return 1;
val[0] = 7;
val[1] = 5;
if (bpf_kfunc_arena_mixed_test((u64 *)&val[0], NULL) != 7)
return 2;
if (bpf_kfunc_arena_mixed_test((u64 *)&val[0], (u64 *)&val[1]) != 12)
return 3;
bpf_arena_free_pages(&arena, (void __arena *)val, 1);
#endif
return 0;
}
/* kernel-side faults on unpopulated pages recover via the scratch page */
SEC("syscall")
__arch_x86_64
__arch_arm64
__success __retval(0)
int arena_arg_unpopulated(void *ctx)
{
#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
u64 __arena *val;
val = bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);
if (!val)
return 1;
stash = (u64)val + PAGE_SIZE;
bpf_kfunc_arena_arg_test((u64 *)stash);
bpf_arena_free_pages(&arena, (void __arena *)val, 1);
#endif
return 0;
}
SEC("syscall")
__arch_x86_64
__arch_arm64
__failure __msg("arena pointer requires a program with an associated arena")
int arena_arg_no_arena(void *ctx)
{
bpf_kfunc_arena_arg_test((u64 *)1);
return 0;
}
SEC("syscall")
__arch_x86_64
__arch_arm64
__failure __msg("is not a pointer to arena or scalar")
int arena_arg_bad_reg(void *ctx)
{
u64 buf = 0;
/* use the arena so the program passes the arena presence check */
bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);
bpf_kfunc_arena_arg_test(&buf);
return 0;
}
#if defined(__BPF_FEATURE_ADDR_SPACE_CAST) && \
defined(__BPF_FEATURE_STACK_ARGUMENT)
SEC("syscall")
__arch_x86_64
__arch_arm64
__failure __msg("arena pointer cannot be a stack argument")
int arena_arg_stack(void *ctx)
{
bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);
bpf_kfunc_arena_stack_arg_test(1, 2, 3, 4, 5, (u64 *)1);
return 0;
}
#else
SEC("syscall")
__arch_x86_64
__arch_arm64
__description("arena_arg_stack: not supported, dummy test")
__success
int arena_arg_stack(void *ctx)
{
return 0;
}
#endif
char _license[] SEC("license") = "GPL";
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