diff options
| -rw-r--r-- | include/linux/bpf_verifier.h | 1 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/prog_tests/task_local_data.h | 386 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/prog_tests/test_task_local_data.c | 297 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/progs/task_local_data.bpf.h | 237 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/progs/test_task_local_data.c | 65 |
5 files changed, 986 insertions, 0 deletions
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index 94defa405c85..c823f8efe3ed 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -962,6 +962,7 @@ static inline bool bpf_prog_check_recur(const struct bpf_prog *prog) case BPF_PROG_TYPE_STRUCT_OPS: return prog->aux->jits_use_priv_stack; case BPF_PROG_TYPE_LSM: + case BPF_PROG_TYPE_SYSCALL: return false; default: return true; diff --git a/tools/testing/selftests/bpf/prog_tests/task_local_data.h b/tools/testing/selftests/bpf/prog_tests/task_local_data.h new file mode 100644 index 000000000000..a408d10c3688 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/task_local_data.h @@ -0,0 +1,386 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __TASK_LOCAL_DATA_H +#define __TASK_LOCAL_DATA_H + +#include <errno.h> +#include <fcntl.h> +#include <sched.h> +#include <stdatomic.h> +#include <stddef.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <sys/syscall.h> +#include <sys/types.h> + +#ifdef TLD_FREE_DATA_ON_THREAD_EXIT +#include <pthread.h> +#endif + +#include <bpf/bpf.h> + +/* + * OPTIONS + * + * Define the option before including the header + * + * TLD_FREE_DATA_ON_THREAD_EXIT - Frees memory on thread exit automatically + * + * Thread-specific memory for storing TLD is allocated lazily on the first call to + * tld_get_data(). The thread that calls it must also call tld_free() on thread exit + * to prevent memory leak. Pthread will be included if the option is defined. A pthread + * key will be registered with a destructor that calls tld_free(). + * + * + * TLD_DYN_DATA_SIZE - The maximum size of memory allocated for TLDs created dynamically + * (default: 64 bytes) + * + * A TLD can be defined statically using TLD_DEFINE_KEY() or created on the fly using + * tld_create_key(). As the total size of TLDs created with tld_create_key() cannot be + * possibly known statically, a memory area of size TLD_DYN_DATA_SIZE will be allocated + * for these TLDs. This additional memory is allocated for every thread that calls + * tld_get_data() even if no tld_create_key are actually called, so be mindful of + * potential memory wastage. Use TLD_DEFINE_KEY() whenever possible as just enough memory + * will be allocated for TLDs created with it. + * + * + * TLD_NAME_LEN - The maximum length of the name of a TLD (default: 62) + * + * Setting TLD_NAME_LEN will affect the maximum number of TLDs a process can store, + * TLD_MAX_DATA_CNT. + * + * + * TLD_DATA_USE_ALIGNED_ALLOC - Always use aligned_alloc() instead of malloc() + * + * When allocating the memory for storing TLDs, we need to make sure there is a memory + * region of the X bytes within a page. This is due to the limit posed by UPTR: memory + * pinned to the kernel cannot exceed a page nor can it cross the page boundary. The + * library normally calls malloc(2*X) given X bytes of total TLDs, and only uses + * aligned_alloc(PAGE_SIZE, X) when X >= PAGE_SIZE / 2. This is to reduce memory wastage + * as not all memory allocator can use the exact amount of memory requested to fulfill + * aligned_alloc(). For example, some may round the size up to the alignment. Enable the + * option to always use aligned_alloc() if the implementation has low memory overhead. + */ + +#define TLD_PAGE_SIZE getpagesize() +#define TLD_PAGE_MASK (~(TLD_PAGE_SIZE - 1)) + +#define TLD_ROUND_MASK(x, y) ((__typeof__(x))((y) - 1)) +#define TLD_ROUND_UP(x, y) ((((x) - 1) | TLD_ROUND_MASK(x, y)) + 1) + +#define TLD_READ_ONCE(x) (*(volatile typeof(x) *)&(x)) + +#ifndef TLD_DYN_DATA_SIZE +#define TLD_DYN_DATA_SIZE 64 +#endif + +#define TLD_MAX_DATA_CNT (TLD_PAGE_SIZE / sizeof(struct tld_metadata) - 1) + +#ifndef TLD_NAME_LEN +#define TLD_NAME_LEN 62 +#endif + +#ifdef __cplusplus +extern "C" { +#endif + +typedef struct { + __s16 off; +} tld_key_t; + +struct tld_metadata { + char name[TLD_NAME_LEN]; + _Atomic __u16 size; +}; + +struct tld_meta_u { + _Atomic __u8 cnt; + __u16 size; + struct tld_metadata metadata[]; +}; + +struct tld_data_u { + __u64 start; /* offset of tld_data_u->data in a page */ + char data[]; +}; + +struct tld_map_value { + void *data; + struct tld_meta_u *meta; +}; + +struct tld_meta_u * _Atomic tld_meta_p __attribute__((weak)); +__thread struct tld_data_u *tld_data_p __attribute__((weak)); +__thread void *tld_data_alloc_p __attribute__((weak)); + +#ifdef TLD_FREE_DATA_ON_THREAD_EXIT +pthread_key_t tld_pthread_key __attribute__((weak)); + +static void tld_free(void); + +static void __tld_thread_exit_handler(void *unused) +{ + tld_free(); +} +#endif + +static int __tld_init_meta_p(void) +{ + struct tld_meta_u *meta, *uninit = NULL; + int err = 0; + + meta = (struct tld_meta_u *)aligned_alloc(TLD_PAGE_SIZE, TLD_PAGE_SIZE); + if (!meta) { + err = -ENOMEM; + goto out; + } + + memset(meta, 0, TLD_PAGE_SIZE); + meta->size = TLD_DYN_DATA_SIZE; + + if (!atomic_compare_exchange_strong(&tld_meta_p, &uninit, meta)) { + free(meta); + goto out; + } + +#ifdef TLD_FREE_DATA_ON_THREAD_EXIT + pthread_key_create(&tld_pthread_key, __tld_thread_exit_handler); +#endif +out: + return err; +} + +static int __tld_init_data_p(int map_fd) +{ + bool use_aligned_alloc = false; + struct tld_map_value map_val; + struct tld_data_u *data; + void *data_alloc = NULL; + int err, tid_fd = -1; + + tid_fd = syscall(SYS_pidfd_open, gettid(), O_EXCL); + if (tid_fd < 0) { + err = -errno; + goto out; + } + +#ifdef TLD_DATA_USE_ALIGNED_ALLOC + use_aligned_alloc = true; +#endif + + /* + * tld_meta_p->size = TLD_DYN_DATA_SIZE + + * total size of TLDs defined via TLD_DEFINE_KEY() + */ + data_alloc = (use_aligned_alloc || tld_meta_p->size * 2 >= TLD_PAGE_SIZE) ? + aligned_alloc(TLD_PAGE_SIZE, tld_meta_p->size) : + malloc(tld_meta_p->size * 2); + if (!data_alloc) { + err = -ENOMEM; + goto out; + } + + /* + * Always pass a page-aligned address to UPTR since the size of tld_map_value::data + * is a page in BTF. If data_alloc spans across two pages, use the page that contains large + * enough memory. + */ + if (TLD_PAGE_SIZE - (~TLD_PAGE_MASK & (intptr_t)data_alloc) >= tld_meta_p->size) { + map_val.data = (void *)(TLD_PAGE_MASK & (intptr_t)data_alloc); + data = data_alloc; + data->start = (~TLD_PAGE_MASK & (intptr_t)data_alloc) + + offsetof(struct tld_data_u, data); + } else { + map_val.data = (void *)(TLD_ROUND_UP((intptr_t)data_alloc, TLD_PAGE_SIZE)); + data = (void *)(TLD_ROUND_UP((intptr_t)data_alloc, TLD_PAGE_SIZE)); + data->start = offsetof(struct tld_data_u, data); + } + map_val.meta = TLD_READ_ONCE(tld_meta_p); + + err = bpf_map_update_elem(map_fd, &tid_fd, &map_val, 0); + if (err) { + free(data_alloc); + goto out; + } + + tld_data_p = data; + tld_data_alloc_p = data_alloc; +#ifdef TLD_FREE_DATA_ON_THREAD_EXIT + pthread_setspecific(tld_pthread_key, (void *)1); +#endif +out: + if (tid_fd >= 0) + close(tid_fd); + return err; +} + +static tld_key_t __tld_create_key(const char *name, size_t size, bool dyn_data) +{ + int err, i, sz, off = 0; + __u8 cnt; + + if (!TLD_READ_ONCE(tld_meta_p)) { + err = __tld_init_meta_p(); + if (err) + return (tld_key_t){err}; + } + + for (i = 0; i < TLD_MAX_DATA_CNT; i++) { +retry: + cnt = atomic_load(&tld_meta_p->cnt); + if (i < cnt) { + /* A metadata is not ready until size is updated with a non-zero value */ + while (!(sz = atomic_load(&tld_meta_p->metadata[i].size))) + sched_yield(); + + if (!strncmp(tld_meta_p->metadata[i].name, name, TLD_NAME_LEN)) + return (tld_key_t){-EEXIST}; + + off += TLD_ROUND_UP(sz, 8); + continue; + } + + /* + * TLD_DEFINE_KEY() is given memory upto a page while at most + * TLD_DYN_DATA_SIZE is allocated for tld_create_key() + */ + if (dyn_data) { + if (off + TLD_ROUND_UP(size, 8) > tld_meta_p->size) + return (tld_key_t){-E2BIG}; + } else { + if (off + TLD_ROUND_UP(size, 8) > TLD_PAGE_SIZE - sizeof(struct tld_data_u)) + return (tld_key_t){-E2BIG}; + tld_meta_p->size += TLD_ROUND_UP(size, 8); + } + + /* + * Only one tld_create_key() can increase the current cnt by one and + * takes the latest available slot. Other threads will check again if a new + * TLD can still be added, and then compete for the new slot after the + * succeeding thread update the size. + */ + if (!atomic_compare_exchange_strong(&tld_meta_p->cnt, &cnt, cnt + 1)) + goto retry; + + strncpy(tld_meta_p->metadata[i].name, name, TLD_NAME_LEN); + atomic_store(&tld_meta_p->metadata[i].size, size); + return (tld_key_t){(__s16)off}; + } + + return (tld_key_t){-ENOSPC}; +} + +/** + * TLD_DEFINE_KEY() - Define a TLD and a global variable key associated with the TLD. + * + * @name: The name of the TLD + * @size: The size of the TLD + * @key: The variable name of the key. Cannot exceed TLD_NAME_LEN + * + * The macro can only be used in file scope. + * + * A global variable key of opaque type, tld_key_t, will be declared and initialized before + * main() starts. Use tld_key_is_err() or tld_key_err_or_zero() later to check if the key + * creation succeeded. Pass the key to tld_get_data() to get a pointer to the TLD. + * bpf programs can also fetch the same key by name. + * + * The total size of TLDs created using TLD_DEFINE_KEY() cannot exceed a page. Just + * enough memory will be allocated for each thread on the first call to tld_get_data(). + */ +#define TLD_DEFINE_KEY(key, name, size) \ +tld_key_t key; \ + \ +__attribute__((constructor)) \ +void __tld_define_key_##key(void) \ +{ \ + key = __tld_create_key(name, size, false); \ +} + +/** + * tld_create_key() - Create a TLD and return a key associated with the TLD. + * + * @name: The name the TLD + * @size: The size of the TLD + * + * Return an opaque object key. Use tld_key_is_err() or tld_key_err_or_zero() to check + * if the key creation succeeded. Pass the key to tld_get_data() to get a pointer to + * locate the TLD. bpf programs can also fetch the same key by name. + * + * Use tld_create_key() only when a TLD needs to be created dynamically (e.g., @name is + * not known statically or a TLD needs to be created conditionally) + * + * An additional TLD_DYN_DATA_SIZE bytes are allocated per-thread to accommodate TLDs + * created dynamically with tld_create_key(). Since only a user page is pinned to the + * kernel, when TLDs created with TLD_DEFINE_KEY() uses more than TLD_PAGE_SIZE - + * TLD_DYN_DATA_SIZE, the buffer size will be limited to the rest of the page. + */ +__attribute__((unused)) +static tld_key_t tld_create_key(const char *name, size_t size) +{ + return __tld_create_key(name, size, true); +} + +__attribute__((unused)) +static inline bool tld_key_is_err(tld_key_t key) +{ + return key.off < 0; +} + +__attribute__((unused)) +static inline int tld_key_err_or_zero(tld_key_t key) +{ + return tld_key_is_err(key) ? key.off : 0; +} + +/** + * tld_get_data() - Get a pointer to the TLD associated with the given key of the + * calling thread. + * + * @map_fd: A file descriptor of tld_data_map, the underlying BPF task local storage map + * of task local data. + * @key: A key object created by TLD_DEFINE_KEY() or tld_create_key(). + * + * Return a pointer to the TLD if the key is valid; NULL if not enough memory for TLD + * for this thread, or the key is invalid. The returned pointer is guaranteed to be 8-byte + * aligned. + * + * Threads that call tld_get_data() must call tld_free() on exit to prevent + * memory leak if TLD_FREE_DATA_ON_THREAD_EXIT is not defined. + */ +__attribute__((unused)) +static void *tld_get_data(int map_fd, tld_key_t key) +{ + if (!TLD_READ_ONCE(tld_meta_p)) + return NULL; + + /* tld_data_p is allocated on the first invocation of tld_get_data() */ + if (!tld_data_p && __tld_init_data_p(map_fd)) + return NULL; + + return tld_data_p->data + key.off; +} + +/** + * tld_free() - Free task local data memory of the calling thread + * + * For the calling thread, all pointers to TLDs acquired before will become invalid. + * + * Users must call tld_free() on thread exit to prevent memory leak. Alternatively, + * define TLD_FREE_DATA_ON_THREAD_EXIT and a thread exit handler will be registered + * to free the memory automatically. + */ +__attribute__((unused)) +static void tld_free(void) +{ + if (tld_data_alloc_p) { + free(tld_data_alloc_p); + tld_data_alloc_p = NULL; + tld_data_p = NULL; + } +} + +#ifdef __cplusplus +} /* extern "C" */ +#endif + +#endif /* __TASK_LOCAL_DATA_H */ diff --git a/tools/testing/selftests/bpf/prog_tests/test_task_local_data.c b/tools/testing/selftests/bpf/prog_tests/test_task_local_data.c new file mode 100644 index 000000000000..3b5cd2cd89c7 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/test_task_local_data.c @@ -0,0 +1,297 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <pthread.h> +#include <bpf/btf.h> +#include <test_progs.h> + +#define TLD_FREE_DATA_ON_THREAD_EXIT +#define TLD_DYN_DATA_SIZE 4096 +#include "task_local_data.h" + +struct test_tld_struct { + __u64 a; + __u64 b; + __u64 c; + __u64 d; +}; + +#include "test_task_local_data.skel.h" + +TLD_DEFINE_KEY(value0_key, "value0", sizeof(int)); + +/* + * Reset task local data between subtests by clearing metadata other + * than the statically defined value0. This is safe as subtests run + * sequentially. Users of task local data library should not touch + * library internal. + */ +static void reset_tld(void) +{ + if (TLD_READ_ONCE(tld_meta_p)) { + /* Remove TLDs created by tld_create_key() */ + tld_meta_p->cnt = 1; + tld_meta_p->size = TLD_DYN_DATA_SIZE; + memset(&tld_meta_p->metadata[1], 0, + (TLD_MAX_DATA_CNT - 1) * sizeof(struct tld_metadata)); + } +} + +/* Serialize access to bpf program's global variables */ +static pthread_mutex_t global_mutex; + +static tld_key_t *tld_keys; + +#define TEST_BASIC_THREAD_NUM 32 + +void *test_task_local_data_basic_thread(void *arg) +{ + LIBBPF_OPTS(bpf_test_run_opts, opts); + struct test_task_local_data *skel = (struct test_task_local_data *)arg; + int fd, err, tid, *value0, *value1; + struct test_tld_struct *value2; + + fd = bpf_map__fd(skel->maps.tld_data_map); + + value0 = tld_get_data(fd, value0_key); + if (!ASSERT_OK_PTR(value0, "tld_get_data")) + goto out; + + value1 = tld_get_data(fd, tld_keys[1]); + if (!ASSERT_OK_PTR(value1, "tld_get_data")) + goto out; + + value2 = tld_get_data(fd, tld_keys[2]); + if (!ASSERT_OK_PTR(value2, "tld_get_data")) + goto out; + + tid = gettid(); + + *value0 = tid + 0; + *value1 = tid + 1; + value2->a = tid + 2; + value2->b = tid + 3; + value2->c = tid + 4; + value2->d = tid + 5; + + pthread_mutex_lock(&global_mutex); + /* Run task_main that read task local data and save to global variables */ + err = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.task_main), &opts); + ASSERT_OK(err, "run task_main"); + ASSERT_OK(opts.retval, "task_main retval"); + + ASSERT_EQ(skel->bss->test_value0, tid + 0, "tld_get_data value0"); + ASSERT_EQ(skel->bss->test_value1, tid + 1, "tld_get_data value1"); + ASSERT_EQ(skel->bss->test_value2.a, tid + 2, "tld_get_data value2.a"); + ASSERT_EQ(skel->bss->test_value2.b, tid + 3, "tld_get_data value2.b"); + ASSERT_EQ(skel->bss->test_value2.c, tid + 4, "tld_get_data value2.c"); + ASSERT_EQ(skel->bss->test_value2.d, tid + 5, "tld_get_data value2.d"); + pthread_mutex_unlock(&global_mutex); + + /* Make sure valueX are indeed local to threads */ + ASSERT_EQ(*value0, tid + 0, "value0"); + ASSERT_EQ(*value1, tid + 1, "value1"); + ASSERT_EQ(value2->a, tid + 2, "value2.a"); + ASSERT_EQ(value2->b, tid + 3, "value2.b"); + ASSERT_EQ(value2->c, tid + 4, "value2.c"); + ASSERT_EQ(value2->d, tid + 5, "value2.d"); + + *value0 = tid + 5; + *value1 = tid + 4; + value2->a = tid + 3; + value2->b = tid + 2; + value2->c = tid + 1; + value2->d = tid + 0; + + /* Run task_main again */ + pthread_mutex_lock(&global_mutex); + err = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.task_main), &opts); + ASSERT_OK(err, "run task_main"); + ASSERT_OK(opts.retval, "task_main retval"); + + ASSERT_EQ(skel->bss->test_value0, tid + 5, "tld_get_data value0"); + ASSERT_EQ(skel->bss->test_value1, tid + 4, "tld_get_data value1"); + ASSERT_EQ(skel->bss->test_value2.a, tid + 3, "tld_get_data value2.a"); + ASSERT_EQ(skel->bss->test_value2.b, tid + 2, "tld_get_data value2.b"); + ASSERT_EQ(skel->bss->test_value2.c, tid + 1, "tld_get_data value2.c"); + ASSERT_EQ(skel->bss->test_value2.d, tid + 0, "tld_get_data value2.d"); + pthread_mutex_unlock(&global_mutex); + +out: + pthread_exit(NULL); +} + +static void test_task_local_data_basic(void) +{ + struct test_task_local_data *skel; + pthread_t thread[TEST_BASIC_THREAD_NUM]; + char dummy_key_name[TLD_NAME_LEN]; + tld_key_t key; + int i, err; + + reset_tld(); + + ASSERT_OK(pthread_mutex_init(&global_mutex, NULL), "pthread_mutex_init"); + + skel = test_task_local_data__open_and_load(); + if (!ASSERT_OK_PTR(skel, "skel_open_and_load")) + return; + + tld_keys = calloc(TLD_MAX_DATA_CNT, sizeof(tld_key_t)); + if (!ASSERT_OK_PTR(tld_keys, "calloc tld_keys")) + goto out; + + ASSERT_FALSE(tld_key_is_err(value0_key), "TLD_DEFINE_KEY"); + tld_keys[1] = tld_create_key("value1", sizeof(int)); + ASSERT_FALSE(tld_key_is_err(tld_keys[1]), "tld_create_key"); + tld_keys[2] = tld_create_key("value2", sizeof(struct test_tld_struct)); + ASSERT_FALSE(tld_key_is_err(tld_keys[2]), "tld_create_key"); + + /* + * Shouldn't be able to store data exceed a page. Create a TLD just big + * enough to exceed a page. TLDs already created are int value0, int + * value1, and struct test_tld_struct value2. + */ + key = tld_create_key("value_not_exist", + TLD_PAGE_SIZE - 2 * sizeof(int) - sizeof(struct test_tld_struct) + 1); + ASSERT_EQ(tld_key_err_or_zero(key), -E2BIG, "tld_create_key"); + + key = tld_create_key("value2", sizeof(struct test_tld_struct)); + ASSERT_EQ(tld_key_err_or_zero(key), -EEXIST, "tld_create_key"); + + /* Shouldn't be able to create the (TLD_MAX_DATA_CNT+1)-th TLD */ + for (i = 3; i < TLD_MAX_DATA_CNT; i++) { + snprintf(dummy_key_name, TLD_NAME_LEN, "dummy_value%d", i); + tld_keys[i] = tld_create_key(dummy_key_name, sizeof(int)); + ASSERT_FALSE(tld_key_is_err(tld_keys[i]), "tld_create_key"); + } + key = tld_create_key("value_not_exist", sizeof(struct test_tld_struct)); + ASSERT_EQ(tld_key_err_or_zero(key), -ENOSPC, "tld_create_key"); + + /* Access TLDs from multiple threads and check if they are thread-specific */ + for (i = 0; i < TEST_BASIC_THREAD_NUM; i++) { + err = pthread_create(&thread[i], NULL, test_task_local_data_basic_thread, skel); + if (!ASSERT_OK(err, "pthread_create")) + goto out; + } + +out: + for (i = 0; i < TEST_BASIC_THREAD_NUM; i++) + pthread_join(thread[i], NULL); + + if (tld_keys) { + free(tld_keys); + tld_keys = NULL; + } + tld_free(); + test_task_local_data__destroy(skel); +} + +#define TEST_RACE_THREAD_NUM (TLD_MAX_DATA_CNT - 3) + +void *test_task_local_data_race_thread(void *arg) +{ + int err = 0, id = (intptr_t)arg; + char key_name[32]; + tld_key_t key; + + key = tld_create_key("value_not_exist", TLD_PAGE_SIZE + 1); + if (tld_key_err_or_zero(key) != -E2BIG) { + err = 1; + goto out; + } + + /* Only one thread will succeed in creating value1 */ + key = tld_create_key("value1", sizeof(int)); + if (!tld_key_is_err(key)) + tld_keys[1] = key; + + /* Only one thread will succeed in creating value2 */ + key = tld_create_key("value2", sizeof(struct test_tld_struct)); + if (!tld_key_is_err(key)) + tld_keys[2] = key; + + snprintf(key_name, 32, "thread_%d", id); + tld_keys[id] = tld_create_key(key_name, sizeof(int)); + if (tld_key_is_err(tld_keys[id])) + err = 2; +out: + return (void *)(intptr_t)err; +} + +static void test_task_local_data_race(void) +{ + LIBBPF_OPTS(bpf_test_run_opts, opts); + pthread_t thread[TEST_RACE_THREAD_NUM]; + struct test_task_local_data *skel; + int fd, i, j, err, *data; + void *ret = NULL; + + skel = test_task_local_data__open_and_load(); + if (!ASSERT_OK_PTR(skel, "skel_open_and_load")) + return; + + tld_keys = calloc(TLD_MAX_DATA_CNT, sizeof(tld_key_t)); + if (!ASSERT_OK_PTR(tld_keys, "calloc tld_keys")) + goto out; + + fd = bpf_map__fd(skel->maps.tld_data_map); + + ASSERT_FALSE(tld_key_is_err(value0_key), "TLD_DEFINE_KEY"); + tld_keys[0] = value0_key; + + for (j = 0; j < 100; j++) { + reset_tld(); + + for (i = 0; i < TEST_RACE_THREAD_NUM; i++) { + /* + * Try to make tld_create_key() race with each other. Call + * tld_create_key(), both valid and invalid, from different threads. + */ + err = pthread_create(&thread[i], NULL, test_task_local_data_race_thread, + (void *)(intptr_t)(i + 3)); + if (CHECK_FAIL(err)) + break; + } + + /* Wait for all tld_create_key() to return */ + for (i = 0; i < TEST_RACE_THREAD_NUM; i++) { + pthread_join(thread[i], &ret); + if (CHECK_FAIL(ret)) + break; + } + + /* Write a unique number to each TLD */ + for (i = 0; i < TLD_MAX_DATA_CNT; i++) { + data = tld_get_data(fd, tld_keys[i]); + if (CHECK_FAIL(!data)) + break; + *data = i; + } + + /* Read TLDs and check the value to see if any address collides with another */ + for (i = 0; i < TLD_MAX_DATA_CNT; i++) { + data = tld_get_data(fd, tld_keys[i]); + if (CHECK_FAIL(*data != i)) + break; + } + + /* Run task_main to make sure no invalid TLDs are added */ + err = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.task_main), &opts); + ASSERT_OK(err, "run task_main"); + ASSERT_OK(opts.retval, "task_main retval"); + } +out: + if (tld_keys) { + free(tld_keys); + tld_keys = NULL; + } + tld_free(); + test_task_local_data__destroy(skel); +} + +void test_task_local_data(void) +{ + if (test__start_subtest("task_local_data_basic")) + test_task_local_data_basic(); + if (test__start_subtest("task_local_data_race")) + test_task_local_data_race(); +} diff --git a/tools/testing/selftests/bpf/progs/task_local_data.bpf.h b/tools/testing/selftests/bpf/progs/task_local_data.bpf.h new file mode 100644 index 000000000000..432fff2af844 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/task_local_data.bpf.h @@ -0,0 +1,237 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __TASK_LOCAL_DATA_BPF_H +#define __TASK_LOCAL_DATA_BPF_H + +/* + * Task local data is a library that facilitates sharing per-task data + * between user space and bpf programs. + * + * + * USAGE + * + * A TLD, an entry of data in task local data, first needs to be created by the + * user space. This is done by calling user space API, TLD_DEFINE_KEY() or + * tld_create_key(), with the name of the TLD and the size. + * + * TLD_DEFINE_KEY(prio, "priority", sizeof(int)); + * + * or + * + * void func_call(...) { + * tld_key_t prio, in_cs; + * + * prio = tld_create_key("priority", sizeof(int)); + * in_cs = tld_create_key("in_critical_section", sizeof(bool)); + * ... + * + * A key associated with the TLD, which has an opaque type tld_key_t, will be + * initialized or returned. It can be used to get a pointer to the TLD in the + * user space by calling tld_get_data(). + * + * In a bpf program, tld_object_init() first needs to be called to initialized a + * tld_object on the stack. Then, TLDs can be accessed by calling tld_get_data(). + * The API will try to fetch the key by the name and use it to locate the data. + * A pointer to the TLD will be returned. It also caches the key in a task local + * storage map, tld_key_map, whose value type, struct tld_keys, must be defined + * by the developer. + * + * struct tld_keys { + * tld_key_t prio; + * tld_key_t in_cs; + * }; + * + * SEC("struct_ops") + * void prog(struct task_struct task, ...) + * { + * struct tld_object tld_obj; + * int err, *p; + * + * err = tld_object_init(task, &tld_obj); + * if (err) + * return; + * + * p = tld_get_data(&tld_obj, prio, "priority", sizeof(int)); + * if (p) + * // do something depending on *p + */ +#include <errno.h> +#include <bpf/bpf_helpers.h> + +#define TLD_ROUND_MASK(x, y) ((__typeof__(x))((y) - 1)) +#define TLD_ROUND_UP(x, y) ((((x) - 1) | TLD_ROUND_MASK(x, y)) + 1) + +#define TLD_MAX_DATA_CNT (__PAGE_SIZE / sizeof(struct tld_metadata) - 1) + +#ifndef TLD_NAME_LEN +#define TLD_NAME_LEN 62 +#endif + +#ifndef TLD_KEY_MAP_CREATE_RETRY +#define TLD_KEY_MAP_CREATE_RETRY 10 +#endif + +typedef struct { + __s16 off; +} tld_key_t; + +struct tld_metadata { + char name[TLD_NAME_LEN]; + __u16 size; +}; + +struct tld_meta_u { + __u8 cnt; + __u16 size; + struct tld_metadata metadata[TLD_MAX_DATA_CNT]; +}; + +struct tld_data_u { + __u64 start; /* offset of tld_data_u->data in a page */ + char data[__PAGE_SIZE - sizeof(__u64)]; +}; + +struct tld_map_value { + struct tld_data_u __uptr *data; + struct tld_meta_u __uptr *meta; +}; + +typedef struct tld_uptr_dummy { + struct tld_data_u data[0]; + struct tld_meta_u meta[0]; +} *tld_uptr_dummy_t; + +struct tld_object { + struct tld_map_value *data_map; + struct tld_keys *key_map; + /* + * Force the compiler to generate the actual definition of tld_meta_u + * and tld_data_u in BTF. Without it, tld_meta_u and u_tld_data will + * be BTF_KIND_FWD. + */ + tld_uptr_dummy_t dummy[0]; +}; + +/* + * Map value of tld_key_map for caching keys. Must be defined by the developer. + * Members should be tld_key_t and passed to the 3rd argument of tld_fetch_key(). + */ +struct tld_keys; + +struct { + __uint(type, BPF_MAP_TYPE_TASK_STORAGE); + __uint(map_flags, BPF_F_NO_PREALLOC); + __type(key, int); + __type(value, struct tld_map_value); +} tld_data_map SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_TASK_STORAGE); + __uint(map_flags, BPF_F_NO_PREALLOC); + __type(key, int); + __type(value, struct tld_keys); +} tld_key_map SEC(".maps"); + +/** + * tld_object_init() - Initialize a tld_object. + * + * @task: The task_struct of the target task + * @tld_obj: A pointer to a tld_object to be initialized + * + * Return 0 on success; -ENODATA if the user space did not initialize task local data + * for the current task through tld_get_data(); -ENOMEM if the creation of tld_key_map + * fails + */ +__attribute__((unused)) +static int tld_object_init(struct task_struct *task, struct tld_object *tld_obj) +{ + int i; + + tld_obj->data_map = bpf_task_storage_get(&tld_data_map, task, 0, 0); + if (!tld_obj->data_map) + return -ENODATA; + + bpf_for(i, 0, TLD_KEY_MAP_CREATE_RETRY) { + tld_obj->key_map = bpf_task_storage_get(&tld_key_map, task, 0, + BPF_LOCAL_STORAGE_GET_F_CREATE); + if (likely(tld_obj->key_map)) + break; + } + if (!tld_obj->key_map) + return -ENOMEM; + + return 0; +} + +/* + * Return the offset of TLD if @name is found. Otherwise, return the current TLD count + * using the nonpositive range so that the next tld_get_data() can skip fetching key if + * no new TLD is added or start comparing name from the first newly added TLD. + */ +__attribute__((unused)) +static int __tld_fetch_key(struct tld_object *tld_obj, const char *name, int i_start) +{ + struct tld_metadata *metadata; + int i, cnt, start, off = 0; + + if (!tld_obj->data_map || !tld_obj->data_map->data || !tld_obj->data_map->meta) + return 0; + + start = tld_obj->data_map->data->start; + cnt = tld_obj->data_map->meta->cnt; + metadata = tld_obj->data_map->meta->metadata; + + bpf_for(i, 0, cnt) { + if (i >= TLD_MAX_DATA_CNT) + break; + + if (i >= i_start && !bpf_strncmp(metadata[i].name, TLD_NAME_LEN, name)) + return start + off; + + off += TLD_ROUND_UP(metadata[i].size, 8); + } + + return -cnt; +} + +/** + * tld_get_data() - Retrieve a pointer to the TLD associated with the name. + * + * @tld_obj: A pointer to a valid tld_object initialized by tld_object_init() + * @key: The cached key of the TLD in tld_key_map + * @name: The name of the key associated with a TLD + * @size: The size of the TLD. Must be a known constant value + * + * Return a pointer to the TLD associated with @name; NULL if not found or @size is too + * big. @key is used to cache the key if the TLD is found to speed up subsequent calls. + * It should be defined as an member of tld_keys of tld_key_t type by the developer. + */ +#define tld_get_data(tld_obj, key, name, size) \ + ({ \ + void *data = NULL, *_data = (tld_obj)->data_map->data; \ + long off = (tld_obj)->key_map->key.off; \ + int cnt; \ + \ + if (likely(_data)) { \ + if (likely(off > 0)) { \ + barrier_var(off); \ + if (likely(off < __PAGE_SIZE - size)) \ + data = _data + off; \ + } else { \ + cnt = -(off); \ + if (likely((tld_obj)->data_map->meta) && \ + cnt < (tld_obj)->data_map->meta->cnt) { \ + off = __tld_fetch_key(tld_obj, name, cnt); \ + (tld_obj)->key_map->key.off = off; \ + \ + if (likely(off < __PAGE_SIZE - size)) { \ + barrier_var(off); \ + if (off > 0) \ + data = _data + off; \ + } \ + } \ + } \ + } \ + data; \ + }) + +#endif diff --git a/tools/testing/selftests/bpf/progs/test_task_local_data.c b/tools/testing/selftests/bpf/progs/test_task_local_data.c new file mode 100644 index 000000000000..fffafc013044 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_task_local_data.c @@ -0,0 +1,65 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <vmlinux.h> +#include <errno.h> +#include <bpf/bpf_helpers.h> + +#include "task_local_data.bpf.h" + +struct tld_keys { + tld_key_t value0; + tld_key_t value1; + tld_key_t value2; + tld_key_t value_not_exist; +}; + +struct test_tld_struct { + __u64 a; + __u64 b; + __u64 c; + __u64 d; +}; + +int test_value0; +int test_value1; +struct test_tld_struct test_value2; + +SEC("syscall") +int task_main(void *ctx) +{ + struct tld_object tld_obj; + struct test_tld_struct *struct_p; + struct task_struct *task; + int err, *int_p; + + task = bpf_get_current_task_btf(); + err = tld_object_init(task, &tld_obj); + if (err) + return 1; + + int_p = tld_get_data(&tld_obj, value0, "value0", sizeof(int)); + if (int_p) + test_value0 = *int_p; + else + return 2; + + int_p = tld_get_data(&tld_obj, value1, "value1", sizeof(int)); + if (int_p) + test_value1 = *int_p; + else + return 3; + + struct_p = tld_get_data(&tld_obj, value2, "value2", sizeof(struct test_tld_struct)); + if (struct_p) + test_value2 = *struct_p; + else + return 4; + + int_p = tld_get_data(&tld_obj, value_not_exist, "value_not_exist", sizeof(int)); + if (int_p) + return 5; + + return 0; +} + +char _license[] SEC("license") = "GPL"; |