cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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libbpf_internal.h (17118B)


      1/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
      2
      3/*
      4 * Internal libbpf helpers.
      5 *
      6 * Copyright (c) 2019 Facebook
      7 */
      8
      9#ifndef __LIBBPF_LIBBPF_INTERNAL_H
     10#define __LIBBPF_LIBBPF_INTERNAL_H
     11
     12#include <stdlib.h>
     13#include <limits.h>
     14#include <errno.h>
     15#include <linux/err.h>
     16#include <fcntl.h>
     17#include <unistd.h>
     18#include "libbpf_legacy.h"
     19#include "relo_core.h"
     20
     21/* make sure libbpf doesn't use kernel-only integer typedefs */
     22#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
     23
     24/* prevent accidental re-addition of reallocarray() */
     25#pragma GCC poison reallocarray
     26
     27#include "libbpf.h"
     28#include "btf.h"
     29
     30#ifndef EM_BPF
     31#define EM_BPF 247
     32#endif
     33
     34#ifndef R_BPF_64_64
     35#define R_BPF_64_64 1
     36#endif
     37#ifndef R_BPF_64_ABS64
     38#define R_BPF_64_ABS64 2
     39#endif
     40#ifndef R_BPF_64_ABS32
     41#define R_BPF_64_ABS32 3
     42#endif
     43#ifndef R_BPF_64_32
     44#define R_BPF_64_32 10
     45#endif
     46
     47#ifndef SHT_LLVM_ADDRSIG
     48#define SHT_LLVM_ADDRSIG 0x6FFF4C03
     49#endif
     50
     51/* if libelf is old and doesn't support mmap(), fall back to read() */
     52#ifndef ELF_C_READ_MMAP
     53#define ELF_C_READ_MMAP ELF_C_READ
     54#endif
     55
     56/* Older libelf all end up in this expression, for both 32 and 64 bit */
     57#ifndef ELF64_ST_VISIBILITY
     58#define ELF64_ST_VISIBILITY(o) ((o) & 0x03)
     59#endif
     60
     61#define BTF_INFO_ENC(kind, kind_flag, vlen) \
     62	((!!(kind_flag) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN))
     63#define BTF_TYPE_ENC(name, info, size_or_type) (name), (info), (size_or_type)
     64#define BTF_INT_ENC(encoding, bits_offset, nr_bits) \
     65	((encoding) << 24 | (bits_offset) << 16 | (nr_bits))
     66#define BTF_TYPE_INT_ENC(name, encoding, bits_offset, bits, sz) \
     67	BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_INT, 0, 0), sz), \
     68	BTF_INT_ENC(encoding, bits_offset, bits)
     69#define BTF_MEMBER_ENC(name, type, bits_offset) (name), (type), (bits_offset)
     70#define BTF_PARAM_ENC(name, type) (name), (type)
     71#define BTF_VAR_SECINFO_ENC(type, offset, size) (type), (offset), (size)
     72#define BTF_TYPE_FLOAT_ENC(name, sz) \
     73	BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_FLOAT, 0, 0), sz)
     74#define BTF_TYPE_DECL_TAG_ENC(value, type, component_idx) \
     75	BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_DECL_TAG, 0, 0), type), (component_idx)
     76#define BTF_TYPE_TYPE_TAG_ENC(value, type) \
     77	BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_TYPE_TAG, 0, 0), type)
     78
     79#ifndef likely
     80#define likely(x) __builtin_expect(!!(x), 1)
     81#endif
     82#ifndef unlikely
     83#define unlikely(x) __builtin_expect(!!(x), 0)
     84#endif
     85#ifndef min
     86# define min(x, y) ((x) < (y) ? (x) : (y))
     87#endif
     88#ifndef max
     89# define max(x, y) ((x) < (y) ? (y) : (x))
     90#endif
     91#ifndef offsetofend
     92# define offsetofend(TYPE, FIELD) \
     93	(offsetof(TYPE, FIELD) + sizeof(((TYPE *)0)->FIELD))
     94#endif
     95#ifndef __alias
     96#define __alias(symbol) __attribute__((alias(#symbol)))
     97#endif
     98
     99/* Check whether a string `str` has prefix `pfx`, regardless if `pfx` is
    100 * a string literal known at compilation time or char * pointer known only at
    101 * runtime.
    102 */
    103#define str_has_pfx(str, pfx) \
    104	(strncmp(str, pfx, __builtin_constant_p(pfx) ? sizeof(pfx) - 1 : strlen(pfx)) == 0)
    105
    106/* suffix check */
    107static inline bool str_has_sfx(const char *str, const char *sfx)
    108{
    109	size_t str_len = strlen(str);
    110	size_t sfx_len = strlen(sfx);
    111
    112	if (sfx_len <= str_len)
    113		return strcmp(str + str_len - sfx_len, sfx);
    114	return false;
    115}
    116
    117/* Symbol versioning is different between static and shared library.
    118 * Properly versioned symbols are needed for shared library, but
    119 * only the symbol of the new version is needed for static library.
    120 * Starting with GNU C 10, use symver attribute instead of .symver assembler
    121 * directive, which works better with GCC LTO builds.
    122 */
    123#if defined(SHARED) && defined(__GNUC__) && __GNUC__ >= 10
    124
    125#define DEFAULT_VERSION(internal_name, api_name, version) \
    126	__attribute__((symver(#api_name "@@" #version)))
    127#define COMPAT_VERSION(internal_name, api_name, version) \
    128	__attribute__((symver(#api_name "@" #version)))
    129
    130#elif defined(SHARED)
    131
    132#define COMPAT_VERSION(internal_name, api_name, version) \
    133	asm(".symver " #internal_name "," #api_name "@" #version);
    134#define DEFAULT_VERSION(internal_name, api_name, version) \
    135	asm(".symver " #internal_name "," #api_name "@@" #version);
    136
    137#else /* !SHARED */
    138
    139#define COMPAT_VERSION(internal_name, api_name, version)
    140#define DEFAULT_VERSION(internal_name, api_name, version) \
    141	extern typeof(internal_name) api_name \
    142	__attribute__((alias(#internal_name)));
    143
    144#endif
    145
    146extern void libbpf_print(enum libbpf_print_level level,
    147			 const char *format, ...)
    148	__attribute__((format(printf, 2, 3)));
    149
    150#define __pr(level, fmt, ...)	\
    151do {				\
    152	libbpf_print(level, "libbpf: " fmt, ##__VA_ARGS__);	\
    153} while (0)
    154
    155#define pr_warn(fmt, ...)	__pr(LIBBPF_WARN, fmt, ##__VA_ARGS__)
    156#define pr_info(fmt, ...)	__pr(LIBBPF_INFO, fmt, ##__VA_ARGS__)
    157#define pr_debug(fmt, ...)	__pr(LIBBPF_DEBUG, fmt, ##__VA_ARGS__)
    158
    159#ifndef __has_builtin
    160#define __has_builtin(x) 0
    161#endif
    162
    163struct bpf_link {
    164	int (*detach)(struct bpf_link *link);
    165	void (*dealloc)(struct bpf_link *link);
    166	char *pin_path;		/* NULL, if not pinned */
    167	int fd;			/* hook FD, -1 if not applicable */
    168	bool disconnected;
    169};
    170
    171/*
    172 * Re-implement glibc's reallocarray() for libbpf internal-only use.
    173 * reallocarray(), unfortunately, is not available in all versions of glibc,
    174 * so requires extra feature detection and using reallocarray() stub from
    175 * <tools/libc_compat.h> and COMPAT_NEED_REALLOCARRAY. All this complicates
    176 * build of libbpf unnecessarily and is just a maintenance burden. Instead,
    177 * it's trivial to implement libbpf-specific internal version and use it
    178 * throughout libbpf.
    179 */
    180static inline void *libbpf_reallocarray(void *ptr, size_t nmemb, size_t size)
    181{
    182	size_t total;
    183
    184#if __has_builtin(__builtin_mul_overflow)
    185	if (unlikely(__builtin_mul_overflow(nmemb, size, &total)))
    186		return NULL;
    187#else
    188	if (size == 0 || nmemb > ULONG_MAX / size)
    189		return NULL;
    190	total = nmemb * size;
    191#endif
    192	return realloc(ptr, total);
    193}
    194
    195/* Copy up to sz - 1 bytes from zero-terminated src string and ensure that dst
    196 * is zero-terminated string no matter what (unless sz == 0, in which case
    197 * it's a no-op). It's conceptually close to FreeBSD's strlcpy(), but differs
    198 * in what is returned. Given this is internal helper, it's trivial to extend
    199 * this, when necessary. Use this instead of strncpy inside libbpf source code.
    200 */
    201static inline void libbpf_strlcpy(char *dst, const char *src, size_t sz)
    202{
    203	size_t i;
    204
    205	if (sz == 0)
    206		return;
    207
    208	sz--;
    209	for (i = 0; i < sz && src[i]; i++)
    210		dst[i] = src[i];
    211	dst[i] = '\0';
    212}
    213
    214__u32 get_kernel_version(void);
    215
    216struct btf;
    217struct btf_type;
    218
    219struct btf_type *btf_type_by_id(const struct btf *btf, __u32 type_id);
    220const char *btf_kind_str(const struct btf_type *t);
    221const struct btf_type *skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id);
    222
    223static inline enum btf_func_linkage btf_func_linkage(const struct btf_type *t)
    224{
    225	return (enum btf_func_linkage)(int)btf_vlen(t);
    226}
    227
    228static inline __u32 btf_type_info(int kind, int vlen, int kflag)
    229{
    230	return (kflag << 31) | (kind << 24) | vlen;
    231}
    232
    233enum map_def_parts {
    234	MAP_DEF_MAP_TYPE	= 0x001,
    235	MAP_DEF_KEY_TYPE	= 0x002,
    236	MAP_DEF_KEY_SIZE	= 0x004,
    237	MAP_DEF_VALUE_TYPE	= 0x008,
    238	MAP_DEF_VALUE_SIZE	= 0x010,
    239	MAP_DEF_MAX_ENTRIES	= 0x020,
    240	MAP_DEF_MAP_FLAGS	= 0x040,
    241	MAP_DEF_NUMA_NODE	= 0x080,
    242	MAP_DEF_PINNING		= 0x100,
    243	MAP_DEF_INNER_MAP	= 0x200,
    244	MAP_DEF_MAP_EXTRA	= 0x400,
    245
    246	MAP_DEF_ALL		= 0x7ff, /* combination of all above */
    247};
    248
    249struct btf_map_def {
    250	enum map_def_parts parts;
    251	__u32 map_type;
    252	__u32 key_type_id;
    253	__u32 key_size;
    254	__u32 value_type_id;
    255	__u32 value_size;
    256	__u32 max_entries;
    257	__u32 map_flags;
    258	__u32 numa_node;
    259	__u32 pinning;
    260	__u64 map_extra;
    261};
    262
    263int parse_btf_map_def(const char *map_name, struct btf *btf,
    264		      const struct btf_type *def_t, bool strict,
    265		      struct btf_map_def *map_def, struct btf_map_def *inner_def);
    266
    267void *libbpf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz,
    268		     size_t cur_cnt, size_t max_cnt, size_t add_cnt);
    269int libbpf_ensure_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t need_cnt);
    270
    271static inline bool libbpf_is_mem_zeroed(const char *p, ssize_t len)
    272{
    273	while (len > 0) {
    274		if (*p)
    275			return false;
    276		p++;
    277		len--;
    278	}
    279	return true;
    280}
    281
    282static inline bool libbpf_validate_opts(const char *opts,
    283					size_t opts_sz, size_t user_sz,
    284					const char *type_name)
    285{
    286	if (user_sz < sizeof(size_t)) {
    287		pr_warn("%s size (%zu) is too small\n", type_name, user_sz);
    288		return false;
    289	}
    290	if (!libbpf_is_mem_zeroed(opts + opts_sz, (ssize_t)user_sz - opts_sz)) {
    291		pr_warn("%s has non-zero extra bytes\n", type_name);
    292		return false;
    293	}
    294	return true;
    295}
    296
    297#define OPTS_VALID(opts, type)						      \
    298	(!(opts) || libbpf_validate_opts((const char *)opts,		      \
    299					 offsetofend(struct type,	      \
    300						     type##__last_field),     \
    301					 (opts)->sz, #type))
    302#define OPTS_HAS(opts, field) \
    303	((opts) && opts->sz >= offsetofend(typeof(*(opts)), field))
    304#define OPTS_GET(opts, field, fallback_value) \
    305	(OPTS_HAS(opts, field) ? (opts)->field : fallback_value)
    306#define OPTS_SET(opts, field, value)		\
    307	do {					\
    308		if (OPTS_HAS(opts, field))	\
    309			(opts)->field = value;	\
    310	} while (0)
    311
    312#define OPTS_ZEROED(opts, last_nonzero_field)				      \
    313({									      \
    314	ssize_t __off = offsetofend(typeof(*(opts)), last_nonzero_field);     \
    315	!(opts) || libbpf_is_mem_zeroed((const void *)opts + __off,	      \
    316					(opts)->sz - __off);		      \
    317})
    318
    319enum kern_feature_id {
    320	/* v4.14: kernel support for program & map names. */
    321	FEAT_PROG_NAME,
    322	/* v5.2: kernel support for global data sections. */
    323	FEAT_GLOBAL_DATA,
    324	/* BTF support */
    325	FEAT_BTF,
    326	/* BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO support */
    327	FEAT_BTF_FUNC,
    328	/* BTF_KIND_VAR and BTF_KIND_DATASEC support */
    329	FEAT_BTF_DATASEC,
    330	/* BTF_FUNC_GLOBAL is supported */
    331	FEAT_BTF_GLOBAL_FUNC,
    332	/* BPF_F_MMAPABLE is supported for arrays */
    333	FEAT_ARRAY_MMAP,
    334	/* kernel support for expected_attach_type in BPF_PROG_LOAD */
    335	FEAT_EXP_ATTACH_TYPE,
    336	/* bpf_probe_read_{kernel,user}[_str] helpers */
    337	FEAT_PROBE_READ_KERN,
    338	/* BPF_PROG_BIND_MAP is supported */
    339	FEAT_PROG_BIND_MAP,
    340	/* Kernel support for module BTFs */
    341	FEAT_MODULE_BTF,
    342	/* BTF_KIND_FLOAT support */
    343	FEAT_BTF_FLOAT,
    344	/* BPF perf link support */
    345	FEAT_PERF_LINK,
    346	/* BTF_KIND_DECL_TAG support */
    347	FEAT_BTF_DECL_TAG,
    348	/* BTF_KIND_TYPE_TAG support */
    349	FEAT_BTF_TYPE_TAG,
    350	/* memcg-based accounting for BPF maps and progs */
    351	FEAT_MEMCG_ACCOUNT,
    352	/* BPF cookie (bpf_get_attach_cookie() BPF helper) support */
    353	FEAT_BPF_COOKIE,
    354	__FEAT_CNT,
    355};
    356
    357int probe_memcg_account(void);
    358bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id);
    359int bump_rlimit_memlock(void);
    360
    361int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz);
    362int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz);
    363int libbpf__load_raw_btf(const char *raw_types, size_t types_len,
    364			 const char *str_sec, size_t str_len);
    365int btf_load_into_kernel(struct btf *btf, char *log_buf, size_t log_sz, __u32 log_level);
    366
    367struct btf *btf_get_from_fd(int btf_fd, struct btf *base_btf);
    368void btf_get_kernel_prefix_kind(enum bpf_attach_type attach_type,
    369				const char **prefix, int *kind);
    370
    371struct btf_ext_info {
    372	/*
    373	 * info points to the individual info section (e.g. func_info and
    374	 * line_info) from the .BTF.ext. It does not include the __u32 rec_size.
    375	 */
    376	void *info;
    377	__u32 rec_size;
    378	__u32 len;
    379	/* optional (maintained internally by libbpf) mapping between .BTF.ext
    380	 * section and corresponding ELF section. This is used to join
    381	 * information like CO-RE relocation records with corresponding BPF
    382	 * programs defined in ELF sections
    383	 */
    384	__u32 *sec_idxs;
    385	int sec_cnt;
    386};
    387
    388#define for_each_btf_ext_sec(seg, sec)					\
    389	for (sec = (seg)->info;						\
    390	     (void *)sec < (seg)->info + (seg)->len;			\
    391	     sec = (void *)sec + sizeof(struct btf_ext_info_sec) +	\
    392		   (seg)->rec_size * sec->num_info)
    393
    394#define for_each_btf_ext_rec(seg, sec, i, rec)				\
    395	for (i = 0, rec = (void *)&(sec)->data;				\
    396	     i < (sec)->num_info;					\
    397	     i++, rec = (void *)rec + (seg)->rec_size)
    398
    399/*
    400 * The .BTF.ext ELF section layout defined as
    401 *   struct btf_ext_header
    402 *   func_info subsection
    403 *
    404 * The func_info subsection layout:
    405 *   record size for struct bpf_func_info in the func_info subsection
    406 *   struct btf_sec_func_info for section #1
    407 *   a list of bpf_func_info records for section #1
    408 *     where struct bpf_func_info mimics one in include/uapi/linux/bpf.h
    409 *     but may not be identical
    410 *   struct btf_sec_func_info for section #2
    411 *   a list of bpf_func_info records for section #2
    412 *   ......
    413 *
    414 * Note that the bpf_func_info record size in .BTF.ext may not
    415 * be the same as the one defined in include/uapi/linux/bpf.h.
    416 * The loader should ensure that record_size meets minimum
    417 * requirement and pass the record as is to the kernel. The
    418 * kernel will handle the func_info properly based on its contents.
    419 */
    420struct btf_ext_header {
    421	__u16	magic;
    422	__u8	version;
    423	__u8	flags;
    424	__u32	hdr_len;
    425
    426	/* All offsets are in bytes relative to the end of this header */
    427	__u32	func_info_off;
    428	__u32	func_info_len;
    429	__u32	line_info_off;
    430	__u32	line_info_len;
    431
    432	/* optional part of .BTF.ext header */
    433	__u32	core_relo_off;
    434	__u32	core_relo_len;
    435};
    436
    437struct btf_ext {
    438	union {
    439		struct btf_ext_header *hdr;
    440		void *data;
    441	};
    442	struct btf_ext_info func_info;
    443	struct btf_ext_info line_info;
    444	struct btf_ext_info core_relo_info;
    445	__u32 data_size;
    446};
    447
    448struct btf_ext_info_sec {
    449	__u32	sec_name_off;
    450	__u32	num_info;
    451	/* Followed by num_info * record_size number of bytes */
    452	__u8	data[];
    453};
    454
    455/* The minimum bpf_func_info checked by the loader */
    456struct bpf_func_info_min {
    457	__u32   insn_off;
    458	__u32   type_id;
    459};
    460
    461/* The minimum bpf_line_info checked by the loader */
    462struct bpf_line_info_min {
    463	__u32	insn_off;
    464	__u32	file_name_off;
    465	__u32	line_off;
    466	__u32	line_col;
    467};
    468
    469
    470typedef int (*type_id_visit_fn)(__u32 *type_id, void *ctx);
    471typedef int (*str_off_visit_fn)(__u32 *str_off, void *ctx);
    472int btf_type_visit_type_ids(struct btf_type *t, type_id_visit_fn visit, void *ctx);
    473int btf_type_visit_str_offs(struct btf_type *t, str_off_visit_fn visit, void *ctx);
    474int btf_ext_visit_type_ids(struct btf_ext *btf_ext, type_id_visit_fn visit, void *ctx);
    475int btf_ext_visit_str_offs(struct btf_ext *btf_ext, str_off_visit_fn visit, void *ctx);
    476__s32 btf__find_by_name_kind_own(const struct btf *btf, const char *type_name,
    477				 __u32 kind);
    478
    479extern enum libbpf_strict_mode libbpf_mode;
    480
    481typedef int (*kallsyms_cb_t)(unsigned long long sym_addr, char sym_type,
    482			     const char *sym_name, void *ctx);
    483
    484int libbpf_kallsyms_parse(kallsyms_cb_t cb, void *arg);
    485
    486/* handle direct returned errors */
    487static inline int libbpf_err(int ret)
    488{
    489	if (ret < 0)
    490		errno = -ret;
    491	return ret;
    492}
    493
    494/* handle errno-based (e.g., syscall or libc) errors according to libbpf's
    495 * strict mode settings
    496 */
    497static inline int libbpf_err_errno(int ret)
    498{
    499	if (libbpf_mode & LIBBPF_STRICT_DIRECT_ERRS)
    500		/* errno is already assumed to be set on error */
    501		return ret < 0 ? -errno : ret;
    502
    503	/* legacy: on error return -1 directly and don't touch errno */
    504	return ret;
    505}
    506
    507/* handle error for pointer-returning APIs, err is assumed to be < 0 always */
    508static inline void *libbpf_err_ptr(int err)
    509{
    510	/* set errno on error, this doesn't break anything */
    511	errno = -err;
    512
    513	if (libbpf_mode & LIBBPF_STRICT_CLEAN_PTRS)
    514		return NULL;
    515
    516	/* legacy: encode err as ptr */
    517	return ERR_PTR(err);
    518}
    519
    520/* handle pointer-returning APIs' error handling */
    521static inline void *libbpf_ptr(void *ret)
    522{
    523	/* set errno on error, this doesn't break anything */
    524	if (IS_ERR(ret))
    525		errno = -PTR_ERR(ret);
    526
    527	if (libbpf_mode & LIBBPF_STRICT_CLEAN_PTRS)
    528		return IS_ERR(ret) ? NULL : ret;
    529
    530	/* legacy: pass-through original pointer */
    531	return ret;
    532}
    533
    534static inline bool str_is_empty(const char *s)
    535{
    536	return !s || !s[0];
    537}
    538
    539static inline bool is_ldimm64_insn(struct bpf_insn *insn)
    540{
    541	return insn->code == (BPF_LD | BPF_IMM | BPF_DW);
    542}
    543
    544/* if fd is stdin, stdout, or stderr, dup to a fd greater than 2
    545 * Takes ownership of the fd passed in, and closes it if calling
    546 * fcntl(fd, F_DUPFD_CLOEXEC, 3).
    547 */
    548static inline int ensure_good_fd(int fd)
    549{
    550	int old_fd = fd, saved_errno;
    551
    552	if (fd < 0)
    553		return fd;
    554	if (fd < 3) {
    555		fd = fcntl(fd, F_DUPFD_CLOEXEC, 3);
    556		saved_errno = errno;
    557		close(old_fd);
    558		if (fd < 0) {
    559			pr_warn("failed to dup FD %d to FD > 2: %d\n", old_fd, -saved_errno);
    560			errno = saved_errno;
    561		}
    562	}
    563	return fd;
    564}
    565
    566/* The following two functions are exposed to bpftool */
    567int bpf_core_add_cands(struct bpf_core_cand *local_cand,
    568		       size_t local_essent_len,
    569		       const struct btf *targ_btf,
    570		       const char *targ_btf_name,
    571		       int targ_start_id,
    572		       struct bpf_core_cand_list *cands);
    573void bpf_core_free_cands(struct bpf_core_cand_list *cands);
    574
    575struct usdt_manager *usdt_manager_new(struct bpf_object *obj);
    576void usdt_manager_free(struct usdt_manager *man);
    577struct bpf_link * usdt_manager_attach_usdt(struct usdt_manager *man,
    578					   const struct bpf_program *prog,
    579					   pid_t pid, const char *path,
    580					   const char *usdt_provider, const char *usdt_name,
    581					   __u64 usdt_cookie);
    582
    583#endif /* __LIBBPF_LIBBPF_INTERNAL_H */