// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */

#define BPF_NO_KFUNC_PROTOTYPES
#include <vmlinux.h>
#include <errno.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
#include "bpf_misc.h"
#include "bpf_experimental.h"
#include <bpf_arena_common.h>

#define private(name) SEC(".bss." #name) __hidden __attribute__((aligned(8)))

struct {
        __uint(type, BPF_MAP_TYPE_ARENA);
        __uint(map_flags, BPF_F_MMAPABLE);
        __uint(max_entries, 2); /* arena of two pages close to 32-bit boundary*/
#ifdef __TARGET_ARCH_arm64
        __ulong(map_extra, (1ull << 32) | (~0u - __PAGE_SIZE * 2 + 1)); /* start of mmap() region */
#else
        __ulong(map_extra, (1ull << 44) | (~0u - __PAGE_SIZE * 2 + 1)); /* start of mmap() region */
#endif
} arena SEC(".maps");

SEC("socket")
__success __retval(0)
int basic_alloc1_nosleep(void *ctx)
{
#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
        volatile int __arena *page1, *page2, *no_page;

        page1 = bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);
        if (!page1)
                return 1;
        *page1 = 1;
        page2 = bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);
        if (!page2)
                return 2;
        *page2 = 2;
        no_page = bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);
        if (no_page)
                return 3;
        if (*page1 != 1)
                return 4;
        if (*page2 != 2)
                return 5;
        bpf_arena_free_pages(&arena, (void __arena *)page2, 1);
        if (*page1 != 1)
                return 6;
        if (*page2 != 0 && *page2 != 2) /* use-after-free should return 0 or the stored value */
                return 7;
#endif
        return 0;
}

SEC("syscall")
__success __retval(0)
int basic_alloc1(void *ctx)
{
#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
        volatile int __arena *page1, *page2, *no_page, *page3;

        page1 = bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);
        if (!page1)
                return 1;
        *page1 = 1;
        page2 = bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);
        if (!page2)
                return 2;
        *page2 = 2;
        no_page = bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);
        if (no_page)
                return 3;
        if (*page1 != 1)
                return 4;
        if (*page2 != 2)
                return 5;
        bpf_arena_free_pages(&arena, (void __arena *)page2, 1);
        if (*page1 != 1)
                return 6;
        if (*page2 != 0) /* use-after-free should return 0 */
                return 7;
        page3 = bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);
        if (!page3)
                return 8;
        *page3 = 3;
        if (page2 != page3)
                return 9;
        if (*page1 != 1)
                return 10;
#endif
        return 0;
}

SEC("socket")
__success __retval(0)
int basic_alloc2_nosleep(void *ctx)
{
#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
        volatile char __arena *page1, *page2, *page3, *page4;

        page1 = bpf_arena_alloc_pages(&arena, NULL, 2, NUMA_NO_NODE, 0);
        if (!page1)
                return 1;
        page2 = page1 + __PAGE_SIZE;
        page3 = page1 + __PAGE_SIZE * 2;
        page4 = page1 - __PAGE_SIZE;
        *page1 = 1;
        *page2 = 2;
        *page3 = 3;
        *page4 = 4;
        if (*page1 != 1)
                return 1;
        if (*page2 != 2)
                return 2;
        if (*page3 != 0)
                return 3;
        if (*page4 != 0)
                return 4;
        bpf_arena_free_pages(&arena, (void __arena *)page1, 2);
        if (*page1 != 0 && *page1 != 1)
                return 5;
        if (*page2 != 0 && *page2 != 2)
                return 6;
        if (*page3 != 0)
                return 7;
        if (*page4 != 0)
                return 8;
#endif
        return 0;
}

SEC("syscall")
__success __retval(0)
int basic_alloc2(void *ctx)
{
#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
        volatile char __arena *page1, *page2, *page3, *page4;

        page1 = bpf_arena_alloc_pages(&arena, NULL, 2, NUMA_NO_NODE, 0);
        if (!page1)
                return 1;
        page2 = page1 + __PAGE_SIZE;
        page3 = page1 + __PAGE_SIZE * 2;
        page4 = page1 - __PAGE_SIZE;
        *page1 = 1;
        *page2 = 2;
        *page3 = 3;
        *page4 = 4;
        if (*page1 != 1)
                return 1;
        if (*page2 != 2)
                return 2;
        if (*page3 != 0)
                return 3;
        if (*page4 != 0)
                return 4;
        bpf_arena_free_pages(&arena, (void __arena *)page1, 2);
        if (*page1 != 0)
                return 5;
        if (*page2 != 0)
                return 6;
        if (*page3 != 0)
                return 7;
        if (*page4 != 0)
                return 8;
#endif
        return 0;
}

struct bpf_arena___l {
        struct bpf_map map;
} __attribute__((preserve_access_index));

SEC("socket")
__success __retval(0) __log_level(2)
int basic_alloc3_nosleep(void *ctx)
{
        struct bpf_arena___l *ar = (struct bpf_arena___l *)&arena;
        volatile char __arena *pages;

        pages = bpf_arena_alloc_pages(&ar->map, NULL, ar->map.max_entries, NUMA_NO_NODE, 0);
        if (!pages)
                return 1;
        return 0;
}

SEC("syscall")
__success __retval(0) __log_level(2)
int basic_alloc3(void *ctx)
{
        struct bpf_arena___l *ar = (struct bpf_arena___l *)&arena;
        volatile char __arena *pages;

        pages = bpf_arena_alloc_pages(&ar->map, NULL, ar->map.max_entries, NUMA_NO_NODE, 0);
        if (!pages)
                return 1;
        return 0;
}

SEC("socket")
__success __retval(0)
int basic_reserve1_nosleep(void *ctx)
{
#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
        char __arena *page;
        int ret;

        page = bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);
        if (!page)
                return 1;

        page += __PAGE_SIZE;

        /* Reserve the second page */
        ret = bpf_arena_reserve_pages(&arena, page, 1);
        if (ret)
                return 2;

        /* Try to explicitly allocate the reserved page. */
        page = bpf_arena_alloc_pages(&arena, page, 1, NUMA_NO_NODE, 0);
        if (page)
                return 3;

        /* Try to implicitly allocate the page (since there's only 2 of them). */
        page = bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);
        if (page)
                return 4;
#endif
        return 0;
}

SEC("syscall")
__success __retval(0)
int basic_reserve1(void *ctx)
{
#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
        char __arena *page;
        int ret;

        page = bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);
        if (!page)
                return 1;

        page += __PAGE_SIZE;

        /* Reserve the second page */
        ret = bpf_arena_reserve_pages(&arena, page, 1);
        if (ret)
                return 2;

        /* Try to explicitly allocate the reserved page. */
        page = bpf_arena_alloc_pages(&arena, page, 1, NUMA_NO_NODE, 0);
        if (page)
                return 3;

        /* Try to implicitly allocate the page (since there's only 2 of them). */
        page = bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);
        if (page)
                return 4;
#endif
        return 0;
}

SEC("socket")
__success __retval(0)
int basic_reserve2_nosleep(void *ctx)
{
#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
        char __arena *page;
        int ret;

        page = arena_base(&arena);
        ret = bpf_arena_reserve_pages(&arena, page, 1);
        if (ret)
                return 1;

        page = bpf_arena_alloc_pages(&arena, page, 1, NUMA_NO_NODE, 0);
        if ((u64)page)
                return 2;
#endif
        return 0;
}

SEC("syscall")
__success __retval(0)
int basic_reserve2(void *ctx)
{
#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
        char __arena *page;
        int ret;

        page = arena_base(&arena);
        ret = bpf_arena_reserve_pages(&arena, page, 1);
        if (ret)
                return 1;

        page = bpf_arena_alloc_pages(&arena, page, 1, NUMA_NO_NODE, 0);
        if ((u64)page)
                return 2;
#endif
        return 0;
}

/* Reserve the same page twice, should return -EBUSY. */
SEC("socket")
__success __retval(0)
int reserve_twice_nosleep(void *ctx)
{
#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
        char __arena *page;
        int ret;

        page = arena_base(&arena);

        ret = bpf_arena_reserve_pages(&arena, page, 1);
        if (ret)
                return 1;

        ret = bpf_arena_reserve_pages(&arena, page, 1);
        if (ret != -EBUSY)
                return 2;
#endif
        return 0;
}

SEC("syscall")
__success __retval(0)
int reserve_twice(void *ctx)
{
#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
        char __arena *page;
        int ret;

        page = arena_base(&arena);

        ret = bpf_arena_reserve_pages(&arena, page, 1);
        if (ret)
                return 1;

        ret = bpf_arena_reserve_pages(&arena, page, 1);
        if (ret != -EBUSY)
                return 2;
#endif
        return 0;
}

/* Try to reserve past the end of the arena. */
SEC("socket")
__success __retval(0)
int reserve_invalid_region_nosleep(void *ctx)
{
#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
        char __arena *page;
        int ret;

        /* Try a NULL pointer. */
        ret = bpf_arena_reserve_pages(&arena, NULL, 3);
        if (ret != -EINVAL)
                return 1;

        page = arena_base(&arena);

        ret = bpf_arena_reserve_pages(&arena, page, 3);
        if (ret != -EINVAL)
                return 2;

        ret = bpf_arena_reserve_pages(&arena, page, 4096);
        if (ret != -EINVAL)
                return 3;

        ret = bpf_arena_reserve_pages(&arena, page, (1ULL << 32) - 1);
        if (ret != -EINVAL)
                return 4;
#endif
        return 0;
}

SEC("syscall")
__success __retval(0)
int reserve_invalid_region(void *ctx)
{
#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
        char __arena *page;
        int ret;

        /* Try a NULL pointer. */
        ret = bpf_arena_reserve_pages(&arena, NULL, 3);
        if (ret != -EINVAL)
                return 1;

        page = arena_base(&arena);

        ret = bpf_arena_reserve_pages(&arena, page, 3);
        if (ret != -EINVAL)
                return 2;

        ret = bpf_arena_reserve_pages(&arena, page, 4096);
        if (ret != -EINVAL)
                return 3;

        ret = bpf_arena_reserve_pages(&arena, page, (1ULL << 32) - 1);
        if (ret != -EINVAL)
                return 4;
#endif
        return 0;
}

SEC("iter.s/bpf_map")
__success __log_level(2)
int iter_maps1(struct bpf_iter__bpf_map *ctx)
{
        struct bpf_map *map = ctx->map;

        if (!map)
                return 0;
        bpf_arena_alloc_pages(map, NULL, map->max_entries, 0, 0);
        return 0;
}

SEC("iter.s/bpf_map")
__failure __msg("expected pointer to STRUCT bpf_map")
int iter_maps2(struct bpf_iter__bpf_map *ctx)
{
        struct seq_file *seq = ctx->meta->seq;

        bpf_arena_alloc_pages((void *)seq, NULL, 1, 0, 0);
        return 0;
}

SEC("iter.s/bpf_map")
__failure __msg("untrusted_ptr_bpf_map")
int iter_maps3(struct bpf_iter__bpf_map *ctx)
{
        struct bpf_map *map = ctx->map;

        if (!map)
                return 0;
        bpf_arena_alloc_pages(map->inner_map_meta, NULL, map->max_entries, 0, 0);
        return 0;
}

private(ARENA_TESTS) struct bpf_spin_lock arena_bpf_test_lock;

/* Use the arena kfunc API while under a BPF lock. */
SEC("syscall")
__success __retval(0)
int arena_kfuncs_under_bpf_lock(void *ctx)
{
#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
        char __arena *page;
        int ret;

        bpf_spin_lock(&arena_bpf_test_lock);

        /* Get a separate region of the arena. */
        page = arena_base(&arena);
        ret = bpf_arena_reserve_pages(&arena, page, 1);
        if (ret) {
                bpf_spin_unlock(&arena_bpf_test_lock);
                return 1;
        }

        bpf_arena_free_pages(&arena, page, 1);

        page = bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);
        if (!page) {
                bpf_spin_unlock(&arena_bpf_test_lock);
                return 2;
        }

        bpf_arena_free_pages(&arena, page, 1);

        bpf_spin_unlock(&arena_bpf_test_lock);
#endif

        return 0;
}

#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)

/*
 * Test that scalar += PTR_TO_ARENA correctly upgrades the
 * destination register to a PTR_TO_ARENA.
 */
SEC("syscall")
__success __retval(0)
int scalar_add_arena_ptr(void *ctx)
{
        int __arena *scalar, *arena_ptr;

        volatile char __arena *base = arena_base(&arena);

        asm volatile (
                "%[arena_ptr] = 8192;"
                "%[arena_ptr] = addr_space_cast(%[arena_ptr], 0x0, 0x1);"
                "%[scalar] = 12;"
                "%[scalar] += %[arena_ptr];"
                : [scalar] "=r"(scalar),
                  [arena_ptr] "=&r"(arena_ptr)
                : "r"(base)
                :
        );
        return 0;
}

/*
 * Tests that PTR_TO_ARENA + PTR_TO_ARENA is allowed.
 */
SEC("syscall")
__success __retval(0)
int arena_ptr_add_arena_ptr(void *ctx)
{
        int __arena *arena_ptr2, *arena_ptr1;

        /* Needed for the verifier to link the arena to the subprog. */
        volatile char __arena *base = arena_base(&arena);

        asm volatile (
                "%[arena_ptr1] = 8192;"
                "%[arena_ptr1] = addr_space_cast(%[arena_ptr1], 0x0, 0x1);"
                "%[arena_ptr2] = 4096;"
                "%[arena_ptr2] = addr_space_cast(%[arena_ptr2], 0x0, 0x1);"
                "%[arena_ptr2] += %[arena_ptr1];"
                : [arena_ptr2] "=r"(arena_ptr2),
                  [arena_ptr1] "=&r"(arena_ptr1)
                : "r"(base)
                :
        );
        return 0;
}

SEC("syscall")
__success __retval(0)
int scalar_xor_arena_ptr(void *ctx)
{
        int __arena *scalar, *arena_ptr;

        volatile char __arena *base = arena_base(&arena);

        asm volatile (
                "%[arena_ptr] = 8192;"
                "%[arena_ptr] = addr_space_cast(%[arena_ptr], 0x0, 0x1);"
                "%[scalar] = 12;"
                "%[scalar] ^= %[arena_ptr];"
                : [scalar] "=r"(scalar),
                  [arena_ptr] "=&r"(arena_ptr)
                : "r"(base)
                :
        );
        return 0;
}

/*
 * Tests that PTR_TO_ARENA and non-arena pointers can be added.
 */
SEC("syscall")
__success __retval(0)
int arena_ptr_add_to_non_arena_ptr(void *ctx)
{
        register int __arena *arena_ptr asm("r3");
        register void *dst asm("r4");

        volatile char __arena *base = arena_base(&arena);

        asm volatile (
                "%[arena_ptr] = 8192;"
                "%[arena_ptr] = addr_space_cast(%[arena_ptr], 0x0, 0x1);"
                "%[dst] = %[ctx];"
                "%[dst] += %[arena_ptr];"
                : [arena_ptr] "=&r"(arena_ptr),
                  [dst] "=&r"(dst)
                : [ctx] "r"(ctx), "r"(base)
                :
        );

        (void)ctx;

        return 0;
}

SEC("syscall")
__success __retval(0)
int non_arena_ptr_add_to_arena_ptr(void *ctx)
{
        register int __arena *arena_ptr asm("r3");
        register void *src asm("r4");

        volatile char __arena *base = arena_base(&arena);

        asm volatile (
                "%[arena_ptr] = 8192;"
                "%[arena_ptr] = addr_space_cast(%[arena_ptr], 0x0, 0x1);"
                "%[src] = %[ctx];"
                "%[arena_ptr] += %[src];"
                : [arena_ptr] "=&r"(arena_ptr),
                  [src] "=&r"(src)
                : [ctx] "r"(ctx), "r"(base)
                :
        );

        (void)ctx;

        return 0;
}

#endif

static __noinline
u32 __arena *check_arena_arg_nonglobal(u32 __arena *arg)
{
        volatile u32 val = *arg;

        *arg = val + 1;

        return arg;
}

__weak
u32 __arena *check_arena_arg_global(u32 __arena *arg)
{
        volatile u32 val = *arg;

        *arg = val + 1;

        return arg;
}

__weak
u32 volatile __arena *check_arena_arg_quals1(u32 volatile __arena *arg1, u32 __arena volatile *arg2)
{
        *arg1 = *arg1 + 1;
        *arg2 = *arg1 + 1;

        return arg2;
}

__weak
u32 __arena volatile *check_arena_arg_quals2(u32 volatile __arena *arg1, u32 __arena volatile *arg2)
{
        *arg1 = *arg1 + 1;
        *arg2 = *arg2 + 1;

        return arg2;
}

SEC("syscall")
__success __retval(0)
int check_arena_arg_ret(void *ctx)
{
        u32 __arena *page = bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);
        u32 __arena *arg = page;
        u32 __arena volatile *arg1;
        u32 __arena volatile *ret1;
        u32 volatile __arena *arg2;
        u32 volatile __arena *ret2;

        if (!arg)
                return 1;

        /* Make sure we use {arg, ret}{1, 2}. */

        arg = check_arena_arg_nonglobal(page);
        arg = check_arena_arg_global(arg);

        arg1 = arg2 = page;
        ret1 = check_arena_arg_quals1(arg1, arg2);
        ret2 = check_arena_arg_quals2(arg1, arg2);

        if (!(*ret1 ||*ret2))
                return -EINVAL;

        return 0;
}

char _license[] SEC("license") = "GPL";