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1/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
2#ifndef __BPF_HELPERS__
3#define __BPF_HELPERS__
4
5/*
6 * Note that bpf programs need to include either
7 * vmlinux.h (auto-generated from BTF) or linux/types.h
8 * in advance since bpf_helper_defs.h uses such types
9 * as __u64.
10 */
11#include "bpf_helper_defs.h"
12
13#define __uint(name, val) int (*name)[val]
14#define __type(name, val) typeof(val) *name
15#define __array(name, val) typeof(val) *name[]
16#define __ulong(name, val) enum { ___bpf_concat(__unique_value, __COUNTER__) = val } name
17
18/*
19 * Helper macro to place programs, maps, license in
20 * different sections in elf_bpf file. Section names
21 * are interpreted by libbpf depending on the context (BPF programs, BPF maps,
22 * extern variables, etc).
23 * To allow use of SEC() with externs (e.g., for extern .maps declarations),
24 * make sure __attribute__((unused)) doesn't trigger compilation warning.
25 */
26#if __GNUC__ && !__clang__
27
28/*
29 * Pragma macros are broken on GCC
30 * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55578
31 * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90400
32 */
33#define SEC(name) __attribute__((section(name), used))
34
35#else
36
37#define SEC(name) \
38 _Pragma("GCC diagnostic push") \
39 _Pragma("GCC diagnostic ignored \"-Wignored-attributes\"") \
40 __attribute__((section(name), used)) \
41 _Pragma("GCC diagnostic pop") \
42
43#endif
44
45/* Avoid 'linux/stddef.h' definition of '__always_inline'. */
46#undef __always_inline
47#define __always_inline inline __attribute__((always_inline))
48
49#ifndef __noinline
50#define __noinline __attribute__((noinline))
51#endif
52#ifndef __weak
53#define __weak __attribute__((weak))
54#endif
55
56/*
57 * Use __hidden attribute to mark a non-static BPF subprogram effectively
58 * static for BPF verifier's verification algorithm purposes, allowing more
59 * extensive and permissive BPF verification process, taking into account
60 * subprogram's caller context.
61 */
62#define __hidden __attribute__((visibility("hidden")))
63
64/* When utilizing vmlinux.h with BPF CO-RE, user BPF programs can't include
65 * any system-level headers (such as stddef.h, linux/version.h, etc), and
66 * commonly-used macros like NULL and KERNEL_VERSION aren't available through
67 * vmlinux.h. This just adds unnecessary hurdles and forces users to re-define
68 * them on their own. So as a convenience, provide such definitions here.
69 */
70#ifndef NULL
71#define NULL ((void *)0)
72#endif
73
74#ifndef KERNEL_VERSION
75#define KERNEL_VERSION(a, b, c) (((a) << 16) + ((b) << 8) + ((c) > 255 ? 255 : (c)))
76#endif
77
78/*
79 * Helper macros to manipulate data structures
80 */
81
82/* offsetof() definition that uses __builtin_offset() might not preserve field
83 * offset CO-RE relocation properly, so force-redefine offsetof() using
84 * old-school approach which works with CO-RE correctly
85 */
86#undef offsetof
87#define offsetof(type, member) ((unsigned long)&((type *)0)->member)
88
89/* redefined container_of() to ensure we use the above offsetof() macro */
90#undef container_of
91#define container_of(ptr, type, member) \
92 ({ \
93 void *__mptr = (void *)(ptr); \
94 ((type *)(__mptr - offsetof(type, member))); \
95 })
96
97/*
98 * Compiler (optimization) barrier.
99 */
100#ifndef barrier
101#define barrier() asm volatile("" ::: "memory")
102#endif
103
104/* Variable-specific compiler (optimization) barrier. It's a no-op which makes
105 * compiler believe that there is some black box modification of a given
106 * variable and thus prevents compiler from making extra assumption about its
107 * value and potential simplifications and optimizations on this variable.
108 *
109 * E.g., compiler might often delay or even omit 32-bit to 64-bit casting of
110 * a variable, making some code patterns unverifiable. Putting barrier_var()
111 * in place will ensure that cast is performed before the barrier_var()
112 * invocation, because compiler has to pessimistically assume that embedded
113 * asm section might perform some extra operations on that variable.
114 *
115 * This is a variable-specific variant of more global barrier().
116 */
117#ifndef barrier_var
118#define barrier_var(var) asm volatile("" : "+r"(var))
119#endif
120
121/*
122 * Helper macro to throw a compilation error if __bpf_unreachable() gets
123 * built into the resulting code. This works given BPF back end does not
124 * implement __builtin_trap(). This is useful to assert that certain paths
125 * of the program code are never used and hence eliminated by the compiler.
126 *
127 * For example, consider a switch statement that covers known cases used by
128 * the program. __bpf_unreachable() can then reside in the default case. If
129 * the program gets extended such that a case is not covered in the switch
130 * statement, then it will throw a build error due to the default case not
131 * being compiled out.
132 */
133#ifndef __bpf_unreachable
134# define __bpf_unreachable() __builtin_trap()
135#endif
136
137/*
138 * Helper function to perform a tail call with a constant/immediate map slot.
139 */
140#if __clang_major__ >= 8 && defined(__bpf__)
141static __always_inline void
142bpf_tail_call_static(void *ctx, const void *map, const __u32 slot)
143{
144 if (!__builtin_constant_p(slot))
145 __bpf_unreachable();
146
147 /*
148 * Provide a hard guarantee that LLVM won't optimize setting r2 (map
149 * pointer) and r3 (constant map index) from _different paths_ ending
150 * up at the _same_ call insn as otherwise we won't be able to use the
151 * jmpq/nopl retpoline-free patching by the x86-64 JIT in the kernel
152 * given they mismatch. See also d2e4c1e6c294 ("bpf: Constant map key
153 * tracking for prog array pokes") for details on verifier tracking.
154 *
155 * Note on clobber list: we need to stay in-line with BPF calling
156 * convention, so even if we don't end up using r0, r4, r5, we need
157 * to mark them as clobber so that LLVM doesn't end up using them
158 * before / after the call.
159 */
160 asm volatile("r1 = %[ctx]\n\t"
161 "r2 = %[map]\n\t"
162 "r3 = %[slot]\n\t"
163 "call 12"
164 :: [ctx]"r"(ctx), [map]"r"(map), [slot]"i"(slot)
165 : "r0", "r1", "r2", "r3", "r4", "r5");
166}
167#endif
168
169enum libbpf_pin_type {
170 LIBBPF_PIN_NONE,
171 /* PIN_BY_NAME: pin maps by name (in /sys/fs/bpf by default) */
172 LIBBPF_PIN_BY_NAME,
173};
174
175enum libbpf_tristate {
176 TRI_NO = 0,
177 TRI_YES = 1,
178 TRI_MODULE = 2,
179};
180
181#define __kconfig __attribute__((section(".kconfig")))
182#define __ksym __attribute__((section(".ksyms")))
183#define __kptr_untrusted __attribute__((btf_type_tag("kptr_untrusted")))
184#define __kptr __attribute__((btf_type_tag("kptr")))
185#define __percpu_kptr __attribute__((btf_type_tag("percpu_kptr")))
186
187#define bpf_ksym_exists(sym) ({ \
188 _Static_assert(!__builtin_constant_p(!!sym), #sym " should be marked as __weak"); \
189 !!sym; \
190})
191
192#define __arg_ctx __attribute__((btf_decl_tag("arg:ctx")))
193#define __arg_nonnull __attribute((btf_decl_tag("arg:nonnull")))
194#define __arg_nullable __attribute((btf_decl_tag("arg:nullable")))
195#define __arg_trusted __attribute((btf_decl_tag("arg:trusted")))
196#define __arg_arena __attribute((btf_decl_tag("arg:arena")))
197
198#ifndef ___bpf_concat
199#define ___bpf_concat(a, b) a ## b
200#endif
201#ifndef ___bpf_apply
202#define ___bpf_apply(fn, n) ___bpf_concat(fn, n)
203#endif
204#ifndef ___bpf_nth
205#define ___bpf_nth(_, _1, _2, _3, _4, _5, _6, _7, _8, _9, _a, _b, _c, N, ...) N
206#endif
207#ifndef ___bpf_narg
208#define ___bpf_narg(...) \
209 ___bpf_nth(_, ##__VA_ARGS__, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
210#endif
211
212#define ___bpf_fill0(arr, p, x) do {} while (0)
213#define ___bpf_fill1(arr, p, x) arr[p] = x
214#define ___bpf_fill2(arr, p, x, args...) arr[p] = x; ___bpf_fill1(arr, p + 1, args)
215#define ___bpf_fill3(arr, p, x, args...) arr[p] = x; ___bpf_fill2(arr, p + 1, args)
216#define ___bpf_fill4(arr, p, x, args...) arr[p] = x; ___bpf_fill3(arr, p + 1, args)
217#define ___bpf_fill5(arr, p, x, args...) arr[p] = x; ___bpf_fill4(arr, p + 1, args)
218#define ___bpf_fill6(arr, p, x, args...) arr[p] = x; ___bpf_fill5(arr, p + 1, args)
219#define ___bpf_fill7(arr, p, x, args...) arr[p] = x; ___bpf_fill6(arr, p + 1, args)
220#define ___bpf_fill8(arr, p, x, args...) arr[p] = x; ___bpf_fill7(arr, p + 1, args)
221#define ___bpf_fill9(arr, p, x, args...) arr[p] = x; ___bpf_fill8(arr, p + 1, args)
222#define ___bpf_fill10(arr, p, x, args...) arr[p] = x; ___bpf_fill9(arr, p + 1, args)
223#define ___bpf_fill11(arr, p, x, args...) arr[p] = x; ___bpf_fill10(arr, p + 1, args)
224#define ___bpf_fill12(arr, p, x, args...) arr[p] = x; ___bpf_fill11(arr, p + 1, args)
225#define ___bpf_fill(arr, args...) \
226 ___bpf_apply(___bpf_fill, ___bpf_narg(args))(arr, 0, args)
227
228/*
229 * BPF_SEQ_PRINTF to wrap bpf_seq_printf to-be-printed values
230 * in a structure.
231 */
232#define BPF_SEQ_PRINTF(seq, fmt, args...) \
233({ \
234 static const char ___fmt[] = fmt; \
235 unsigned long long ___param[___bpf_narg(args)]; \
236 \
237 _Pragma("GCC diagnostic push") \
238 _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \
239 ___bpf_fill(___param, args); \
240 _Pragma("GCC diagnostic pop") \
241 \
242 bpf_seq_printf(seq, ___fmt, sizeof(___fmt), \
243 ___param, sizeof(___param)); \
244})
245
246/*
247 * BPF_SNPRINTF wraps the bpf_snprintf helper with variadic arguments instead of
248 * an array of u64.
249 */
250#define BPF_SNPRINTF(out, out_size, fmt, args...) \
251({ \
252 static const char ___fmt[] = fmt; \
253 unsigned long long ___param[___bpf_narg(args)]; \
254 \
255 _Pragma("GCC diagnostic push") \
256 _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \
257 ___bpf_fill(___param, args); \
258 _Pragma("GCC diagnostic pop") \
259 \
260 bpf_snprintf(out, out_size, ___fmt, \
261 ___param, sizeof(___param)); \
262})
263
264#ifdef BPF_NO_GLOBAL_DATA
265#define BPF_PRINTK_FMT_MOD
266#else
267#define BPF_PRINTK_FMT_MOD static const
268#endif
269
270#define __bpf_printk(fmt, ...) \
271({ \
272 BPF_PRINTK_FMT_MOD char ____fmt[] = fmt; \
273 bpf_trace_printk(____fmt, sizeof(____fmt), \
274 ##__VA_ARGS__); \
275})
276
277/*
278 * __bpf_vprintk wraps the bpf_trace_vprintk helper with variadic arguments
279 * instead of an array of u64.
280 */
281#define __bpf_vprintk(fmt, args...) \
282({ \
283 static const char ___fmt[] = fmt; \
284 unsigned long long ___param[___bpf_narg(args)]; \
285 \
286 _Pragma("GCC diagnostic push") \
287 _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \
288 ___bpf_fill(___param, args); \
289 _Pragma("GCC diagnostic pop") \
290 \
291 bpf_trace_vprintk(___fmt, sizeof(___fmt), \
292 ___param, sizeof(___param)); \
293})
294
295/* Use __bpf_printk when bpf_printk call has 3 or fewer fmt args
296 * Otherwise use __bpf_vprintk
297 */
298#define ___bpf_pick_printk(...) \
299 ___bpf_nth(_, ##__VA_ARGS__, __bpf_vprintk, __bpf_vprintk, __bpf_vprintk, \
300 __bpf_vprintk, __bpf_vprintk, __bpf_vprintk, __bpf_vprintk, \
301 __bpf_vprintk, __bpf_vprintk, __bpf_printk /*3*/, __bpf_printk /*2*/,\
302 __bpf_printk /*1*/, __bpf_printk /*0*/)
303
304/* Helper macro to print out debug messages */
305#define bpf_printk(fmt, args...) ___bpf_pick_printk(args)(fmt, ##args)
306
307struct bpf_iter_num;
308
309extern int bpf_iter_num_new(struct bpf_iter_num *it, int start, int end) __weak __ksym;
310extern int *bpf_iter_num_next(struct bpf_iter_num *it) __weak __ksym;
311extern void bpf_iter_num_destroy(struct bpf_iter_num *it) __weak __ksym;
312
313#ifndef bpf_for_each
314/* bpf_for_each(iter_type, cur_elem, args...) provides generic construct for
315 * using BPF open-coded iterators without having to write mundane explicit
316 * low-level loop logic. Instead, it provides for()-like generic construct
317 * that can be used pretty naturally. E.g., for some hypothetical cgroup
318 * iterator, you'd write:
319 *
320 * struct cgroup *cg, *parent_cg = <...>;
321 *
322 * bpf_for_each(cgroup, cg, parent_cg, CG_ITER_CHILDREN) {
323 * bpf_printk("Child cgroup id = %d", cg->cgroup_id);
324 * if (cg->cgroup_id == 123)
325 * break;
326 * }
327 *
328 * I.e., it looks almost like high-level for each loop in other languages,
329 * supports continue/break, and is verifiable by BPF verifier.
330 *
331 * For iterating integers, the difference betwen bpf_for_each(num, i, N, M)
332 * and bpf_for(i, N, M) is in that bpf_for() provides additional proof to
333 * verifier that i is in [N, M) range, and in bpf_for_each() case i is `int
334 * *`, not just `int`. So for integers bpf_for() is more convenient.
335 *
336 * Note: this macro relies on C99 feature of allowing to declare variables
337 * inside for() loop, bound to for() loop lifetime. It also utilizes GCC
338 * extension: __attribute__((cleanup(<func>))), supported by both GCC and
339 * Clang.
340 */
341#define bpf_for_each(type, cur, args...) for ( \
342 /* initialize and define destructor */ \
343 struct bpf_iter_##type ___it __attribute__((aligned(8), /* enforce, just in case */, \
344 cleanup(bpf_iter_##type##_destroy))), \
345 /* ___p pointer is just to call bpf_iter_##type##_new() *once* to init ___it */ \
346 *___p __attribute__((unused)) = ( \
347 bpf_iter_##type##_new(&___it, ##args), \
348 /* this is a workaround for Clang bug: it currently doesn't emit BTF */ \
349 /* for bpf_iter_##type##_destroy() when used from cleanup() attribute */ \
350 (void)bpf_iter_##type##_destroy, (void *)0); \
351 /* iteration and termination check */ \
352 (((cur) = bpf_iter_##type##_next(&___it))); \
353)
354#endif /* bpf_for_each */
355
356#ifndef bpf_for
357/* bpf_for(i, start, end) implements a for()-like looping construct that sets
358 * provided integer variable *i* to values starting from *start* through,
359 * but not including, *end*. It also proves to BPF verifier that *i* belongs
360 * to range [start, end), so this can be used for accessing arrays without
361 * extra checks.
362 *
363 * Note: *start* and *end* are assumed to be expressions with no side effects
364 * and whose values do not change throughout bpf_for() loop execution. They do
365 * not have to be statically known or constant, though.
366 *
367 * Note: similarly to bpf_for_each(), it relies on C99 feature of declaring for()
368 * loop bound variables and cleanup attribute, supported by GCC and Clang.
369 */
370#define bpf_for(i, start, end) for ( \
371 /* initialize and define destructor */ \
372 struct bpf_iter_num ___it __attribute__((aligned(8), /* enforce, just in case */ \
373 cleanup(bpf_iter_num_destroy))), \
374 /* ___p pointer is necessary to call bpf_iter_num_new() *once* to init ___it */ \
375 *___p __attribute__((unused)) = ( \
376 bpf_iter_num_new(&___it, (start), (end)), \
377 /* this is a workaround for Clang bug: it currently doesn't emit BTF */ \
378 /* for bpf_iter_num_destroy() when used from cleanup() attribute */ \
379 (void)bpf_iter_num_destroy, (void *)0); \
380 ({ \
381 /* iteration step */ \
382 int *___t = bpf_iter_num_next(&___it); \
383 /* termination and bounds check */ \
384 (___t && ((i) = *___t, (i) >= (start) && (i) < (end))); \
385 }); \
386)
387#endif /* bpf_for */
388
389#ifndef bpf_repeat
390/* bpf_repeat(N) performs N iterations without exposing iteration number
391 *
392 * Note: similarly to bpf_for_each(), it relies on C99 feature of declaring for()
393 * loop bound variables and cleanup attribute, supported by GCC and Clang.
394 */
395#define bpf_repeat(N) for ( \
396 /* initialize and define destructor */ \
397 struct bpf_iter_num ___it __attribute__((aligned(8), /* enforce, just in case */ \
398 cleanup(bpf_iter_num_destroy))), \
399 /* ___p pointer is necessary to call bpf_iter_num_new() *once* to init ___it */ \
400 *___p __attribute__((unused)) = ( \
401 bpf_iter_num_new(&___it, 0, (N)), \
402 /* this is a workaround for Clang bug: it currently doesn't emit BTF */ \
403 /* for bpf_iter_num_destroy() when used from cleanup() attribute */ \
404 (void)bpf_iter_num_destroy, (void *)0); \
405 bpf_iter_num_next(&___it); \
406 /* nothing here */ \
407)
408#endif /* bpf_repeat */
409
410#endif
1/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
2#ifndef __BPF_HELPERS__
3#define __BPF_HELPERS__
4
5/*
6 * Note that bpf programs need to include either
7 * vmlinux.h (auto-generated from BTF) or linux/types.h
8 * in advance since bpf_helper_defs.h uses such types
9 * as __u64.
10 */
11#include "bpf_helper_defs.h"
12
13#define __uint(name, val) int (*name)[val]
14#define __type(name, val) typeof(val) *name
15#define __array(name, val) typeof(val) *name[]
16
17/*
18 * Helper macro to place programs, maps, license in
19 * different sections in elf_bpf file. Section names
20 * are interpreted by libbpf depending on the context (BPF programs, BPF maps,
21 * extern variables, etc).
22 * To allow use of SEC() with externs (e.g., for extern .maps declarations),
23 * make sure __attribute__((unused)) doesn't trigger compilation warning.
24 */
25#if __GNUC__ && !__clang__
26
27/*
28 * Pragma macros are broken on GCC
29 * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55578
30 * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90400
31 */
32#define SEC(name) __attribute__((section(name), used))
33
34#else
35
36#define SEC(name) \
37 _Pragma("GCC diagnostic push") \
38 _Pragma("GCC diagnostic ignored \"-Wignored-attributes\"") \
39 __attribute__((section(name), used)) \
40 _Pragma("GCC diagnostic pop") \
41
42#endif
43
44/* Avoid 'linux/stddef.h' definition of '__always_inline'. */
45#undef __always_inline
46#define __always_inline inline __attribute__((always_inline))
47
48#ifndef __noinline
49#define __noinline __attribute__((noinline))
50#endif
51#ifndef __weak
52#define __weak __attribute__((weak))
53#endif
54
55/*
56 * Use __hidden attribute to mark a non-static BPF subprogram effectively
57 * static for BPF verifier's verification algorithm purposes, allowing more
58 * extensive and permissive BPF verification process, taking into account
59 * subprogram's caller context.
60 */
61#define __hidden __attribute__((visibility("hidden")))
62
63/* When utilizing vmlinux.h with BPF CO-RE, user BPF programs can't include
64 * any system-level headers (such as stddef.h, linux/version.h, etc), and
65 * commonly-used macros like NULL and KERNEL_VERSION aren't available through
66 * vmlinux.h. This just adds unnecessary hurdles and forces users to re-define
67 * them on their own. So as a convenience, provide such definitions here.
68 */
69#ifndef NULL
70#define NULL ((void *)0)
71#endif
72
73#ifndef KERNEL_VERSION
74#define KERNEL_VERSION(a, b, c) (((a) << 16) + ((b) << 8) + ((c) > 255 ? 255 : (c)))
75#endif
76
77/*
78 * Helper macros to manipulate data structures
79 */
80
81/* offsetof() definition that uses __builtin_offset() might not preserve field
82 * offset CO-RE relocation properly, so force-redefine offsetof() using
83 * old-school approach which works with CO-RE correctly
84 */
85#undef offsetof
86#define offsetof(type, member) ((unsigned long)&((type *)0)->member)
87
88/* redefined container_of() to ensure we use the above offsetof() macro */
89#undef container_of
90#define container_of(ptr, type, member) \
91 ({ \
92 void *__mptr = (void *)(ptr); \
93 ((type *)(__mptr - offsetof(type, member))); \
94 })
95
96/*
97 * Compiler (optimization) barrier.
98 */
99#ifndef barrier
100#define barrier() asm volatile("" ::: "memory")
101#endif
102
103/* Variable-specific compiler (optimization) barrier. It's a no-op which makes
104 * compiler believe that there is some black box modification of a given
105 * variable and thus prevents compiler from making extra assumption about its
106 * value and potential simplifications and optimizations on this variable.
107 *
108 * E.g., compiler might often delay or even omit 32-bit to 64-bit casting of
109 * a variable, making some code patterns unverifiable. Putting barrier_var()
110 * in place will ensure that cast is performed before the barrier_var()
111 * invocation, because compiler has to pessimistically assume that embedded
112 * asm section might perform some extra operations on that variable.
113 *
114 * This is a variable-specific variant of more global barrier().
115 */
116#ifndef barrier_var
117#define barrier_var(var) asm volatile("" : "+r"(var))
118#endif
119
120/*
121 * Helper macro to throw a compilation error if __bpf_unreachable() gets
122 * built into the resulting code. This works given BPF back end does not
123 * implement __builtin_trap(). This is useful to assert that certain paths
124 * of the program code are never used and hence eliminated by the compiler.
125 *
126 * For example, consider a switch statement that covers known cases used by
127 * the program. __bpf_unreachable() can then reside in the default case. If
128 * the program gets extended such that a case is not covered in the switch
129 * statement, then it will throw a build error due to the default case not
130 * being compiled out.
131 */
132#ifndef __bpf_unreachable
133# define __bpf_unreachable() __builtin_trap()
134#endif
135
136/*
137 * Helper function to perform a tail call with a constant/immediate map slot.
138 */
139#if __clang_major__ >= 8 && defined(__bpf__)
140static __always_inline void
141bpf_tail_call_static(void *ctx, const void *map, const __u32 slot)
142{
143 if (!__builtin_constant_p(slot))
144 __bpf_unreachable();
145
146 /*
147 * Provide a hard guarantee that LLVM won't optimize setting r2 (map
148 * pointer) and r3 (constant map index) from _different paths_ ending
149 * up at the _same_ call insn as otherwise we won't be able to use the
150 * jmpq/nopl retpoline-free patching by the x86-64 JIT in the kernel
151 * given they mismatch. See also d2e4c1e6c294 ("bpf: Constant map key
152 * tracking for prog array pokes") for details on verifier tracking.
153 *
154 * Note on clobber list: we need to stay in-line with BPF calling
155 * convention, so even if we don't end up using r0, r4, r5, we need
156 * to mark them as clobber so that LLVM doesn't end up using them
157 * before / after the call.
158 */
159 asm volatile("r1 = %[ctx]\n\t"
160 "r2 = %[map]\n\t"
161 "r3 = %[slot]\n\t"
162 "call 12"
163 :: [ctx]"r"(ctx), [map]"r"(map), [slot]"i"(slot)
164 : "r0", "r1", "r2", "r3", "r4", "r5");
165}
166#endif
167
168enum libbpf_pin_type {
169 LIBBPF_PIN_NONE,
170 /* PIN_BY_NAME: pin maps by name (in /sys/fs/bpf by default) */
171 LIBBPF_PIN_BY_NAME,
172};
173
174enum libbpf_tristate {
175 TRI_NO = 0,
176 TRI_YES = 1,
177 TRI_MODULE = 2,
178};
179
180#define __kconfig __attribute__((section(".kconfig")))
181#define __ksym __attribute__((section(".ksyms")))
182#define __kptr_untrusted __attribute__((btf_type_tag("kptr_untrusted")))
183#define __kptr __attribute__((btf_type_tag("kptr")))
184#define __percpu_kptr __attribute__((btf_type_tag("percpu_kptr")))
185
186#define bpf_ksym_exists(sym) ({ \
187 _Static_assert(!__builtin_constant_p(!!sym), #sym " should be marked as __weak"); \
188 !!sym; \
189})
190
191#define __arg_ctx __attribute__((btf_decl_tag("arg:ctx")))
192#define __arg_nonnull __attribute((btf_decl_tag("arg:nonnull")))
193
194#ifndef ___bpf_concat
195#define ___bpf_concat(a, b) a ## b
196#endif
197#ifndef ___bpf_apply
198#define ___bpf_apply(fn, n) ___bpf_concat(fn, n)
199#endif
200#ifndef ___bpf_nth
201#define ___bpf_nth(_, _1, _2, _3, _4, _5, _6, _7, _8, _9, _a, _b, _c, N, ...) N
202#endif
203#ifndef ___bpf_narg
204#define ___bpf_narg(...) \
205 ___bpf_nth(_, ##__VA_ARGS__, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
206#endif
207
208#define ___bpf_fill0(arr, p, x) do {} while (0)
209#define ___bpf_fill1(arr, p, x) arr[p] = x
210#define ___bpf_fill2(arr, p, x, args...) arr[p] = x; ___bpf_fill1(arr, p + 1, args)
211#define ___bpf_fill3(arr, p, x, args...) arr[p] = x; ___bpf_fill2(arr, p + 1, args)
212#define ___bpf_fill4(arr, p, x, args...) arr[p] = x; ___bpf_fill3(arr, p + 1, args)
213#define ___bpf_fill5(arr, p, x, args...) arr[p] = x; ___bpf_fill4(arr, p + 1, args)
214#define ___bpf_fill6(arr, p, x, args...) arr[p] = x; ___bpf_fill5(arr, p + 1, args)
215#define ___bpf_fill7(arr, p, x, args...) arr[p] = x; ___bpf_fill6(arr, p + 1, args)
216#define ___bpf_fill8(arr, p, x, args...) arr[p] = x; ___bpf_fill7(arr, p + 1, args)
217#define ___bpf_fill9(arr, p, x, args...) arr[p] = x; ___bpf_fill8(arr, p + 1, args)
218#define ___bpf_fill10(arr, p, x, args...) arr[p] = x; ___bpf_fill9(arr, p + 1, args)
219#define ___bpf_fill11(arr, p, x, args...) arr[p] = x; ___bpf_fill10(arr, p + 1, args)
220#define ___bpf_fill12(arr, p, x, args...) arr[p] = x; ___bpf_fill11(arr, p + 1, args)
221#define ___bpf_fill(arr, args...) \
222 ___bpf_apply(___bpf_fill, ___bpf_narg(args))(arr, 0, args)
223
224/*
225 * BPF_SEQ_PRINTF to wrap bpf_seq_printf to-be-printed values
226 * in a structure.
227 */
228#define BPF_SEQ_PRINTF(seq, fmt, args...) \
229({ \
230 static const char ___fmt[] = fmt; \
231 unsigned long long ___param[___bpf_narg(args)]; \
232 \
233 _Pragma("GCC diagnostic push") \
234 _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \
235 ___bpf_fill(___param, args); \
236 _Pragma("GCC diagnostic pop") \
237 \
238 bpf_seq_printf(seq, ___fmt, sizeof(___fmt), \
239 ___param, sizeof(___param)); \
240})
241
242/*
243 * BPF_SNPRINTF wraps the bpf_snprintf helper with variadic arguments instead of
244 * an array of u64.
245 */
246#define BPF_SNPRINTF(out, out_size, fmt, args...) \
247({ \
248 static const char ___fmt[] = fmt; \
249 unsigned long long ___param[___bpf_narg(args)]; \
250 \
251 _Pragma("GCC diagnostic push") \
252 _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \
253 ___bpf_fill(___param, args); \
254 _Pragma("GCC diagnostic pop") \
255 \
256 bpf_snprintf(out, out_size, ___fmt, \
257 ___param, sizeof(___param)); \
258})
259
260#ifdef BPF_NO_GLOBAL_DATA
261#define BPF_PRINTK_FMT_MOD
262#else
263#define BPF_PRINTK_FMT_MOD static const
264#endif
265
266#define __bpf_printk(fmt, ...) \
267({ \
268 BPF_PRINTK_FMT_MOD char ____fmt[] = fmt; \
269 bpf_trace_printk(____fmt, sizeof(____fmt), \
270 ##__VA_ARGS__); \
271})
272
273/*
274 * __bpf_vprintk wraps the bpf_trace_vprintk helper with variadic arguments
275 * instead of an array of u64.
276 */
277#define __bpf_vprintk(fmt, args...) \
278({ \
279 static const char ___fmt[] = fmt; \
280 unsigned long long ___param[___bpf_narg(args)]; \
281 \
282 _Pragma("GCC diagnostic push") \
283 _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \
284 ___bpf_fill(___param, args); \
285 _Pragma("GCC diagnostic pop") \
286 \
287 bpf_trace_vprintk(___fmt, sizeof(___fmt), \
288 ___param, sizeof(___param)); \
289})
290
291/* Use __bpf_printk when bpf_printk call has 3 or fewer fmt args
292 * Otherwise use __bpf_vprintk
293 */
294#define ___bpf_pick_printk(...) \
295 ___bpf_nth(_, ##__VA_ARGS__, __bpf_vprintk, __bpf_vprintk, __bpf_vprintk, \
296 __bpf_vprintk, __bpf_vprintk, __bpf_vprintk, __bpf_vprintk, \
297 __bpf_vprintk, __bpf_vprintk, __bpf_printk /*3*/, __bpf_printk /*2*/,\
298 __bpf_printk /*1*/, __bpf_printk /*0*/)
299
300/* Helper macro to print out debug messages */
301#define bpf_printk(fmt, args...) ___bpf_pick_printk(args)(fmt, ##args)
302
303struct bpf_iter_num;
304
305extern int bpf_iter_num_new(struct bpf_iter_num *it, int start, int end) __weak __ksym;
306extern int *bpf_iter_num_next(struct bpf_iter_num *it) __weak __ksym;
307extern void bpf_iter_num_destroy(struct bpf_iter_num *it) __weak __ksym;
308
309#ifndef bpf_for_each
310/* bpf_for_each(iter_type, cur_elem, args...) provides generic construct for
311 * using BPF open-coded iterators without having to write mundane explicit
312 * low-level loop logic. Instead, it provides for()-like generic construct
313 * that can be used pretty naturally. E.g., for some hypothetical cgroup
314 * iterator, you'd write:
315 *
316 * struct cgroup *cg, *parent_cg = <...>;
317 *
318 * bpf_for_each(cgroup, cg, parent_cg, CG_ITER_CHILDREN) {
319 * bpf_printk("Child cgroup id = %d", cg->cgroup_id);
320 * if (cg->cgroup_id == 123)
321 * break;
322 * }
323 *
324 * I.e., it looks almost like high-level for each loop in other languages,
325 * supports continue/break, and is verifiable by BPF verifier.
326 *
327 * For iterating integers, the difference betwen bpf_for_each(num, i, N, M)
328 * and bpf_for(i, N, M) is in that bpf_for() provides additional proof to
329 * verifier that i is in [N, M) range, and in bpf_for_each() case i is `int
330 * *`, not just `int`. So for integers bpf_for() is more convenient.
331 *
332 * Note: this macro relies on C99 feature of allowing to declare variables
333 * inside for() loop, bound to for() loop lifetime. It also utilizes GCC
334 * extension: __attribute__((cleanup(<func>))), supported by both GCC and
335 * Clang.
336 */
337#define bpf_for_each(type, cur, args...) for ( \
338 /* initialize and define destructor */ \
339 struct bpf_iter_##type ___it __attribute__((aligned(8), /* enforce, just in case */, \
340 cleanup(bpf_iter_##type##_destroy))), \
341 /* ___p pointer is just to call bpf_iter_##type##_new() *once* to init ___it */ \
342 *___p __attribute__((unused)) = ( \
343 bpf_iter_##type##_new(&___it, ##args), \
344 /* this is a workaround for Clang bug: it currently doesn't emit BTF */ \
345 /* for bpf_iter_##type##_destroy() when used from cleanup() attribute */ \
346 (void)bpf_iter_##type##_destroy, (void *)0); \
347 /* iteration and termination check */ \
348 (((cur) = bpf_iter_##type##_next(&___it))); \
349)
350#endif /* bpf_for_each */
351
352#ifndef bpf_for
353/* bpf_for(i, start, end) implements a for()-like looping construct that sets
354 * provided integer variable *i* to values starting from *start* through,
355 * but not including, *end*. It also proves to BPF verifier that *i* belongs
356 * to range [start, end), so this can be used for accessing arrays without
357 * extra checks.
358 *
359 * Note: *start* and *end* are assumed to be expressions with no side effects
360 * and whose values do not change throughout bpf_for() loop execution. They do
361 * not have to be statically known or constant, though.
362 *
363 * Note: similarly to bpf_for_each(), it relies on C99 feature of declaring for()
364 * loop bound variables and cleanup attribute, supported by GCC and Clang.
365 */
366#define bpf_for(i, start, end) for ( \
367 /* initialize and define destructor */ \
368 struct bpf_iter_num ___it __attribute__((aligned(8), /* enforce, just in case */ \
369 cleanup(bpf_iter_num_destroy))), \
370 /* ___p pointer is necessary to call bpf_iter_num_new() *once* to init ___it */ \
371 *___p __attribute__((unused)) = ( \
372 bpf_iter_num_new(&___it, (start), (end)), \
373 /* this is a workaround for Clang bug: it currently doesn't emit BTF */ \
374 /* for bpf_iter_num_destroy() when used from cleanup() attribute */ \
375 (void)bpf_iter_num_destroy, (void *)0); \
376 ({ \
377 /* iteration step */ \
378 int *___t = bpf_iter_num_next(&___it); \
379 /* termination and bounds check */ \
380 (___t && ((i) = *___t, (i) >= (start) && (i) < (end))); \
381 }); \
382)
383#endif /* bpf_for */
384
385#ifndef bpf_repeat
386/* bpf_repeat(N) performs N iterations without exposing iteration number
387 *
388 * Note: similarly to bpf_for_each(), it relies on C99 feature of declaring for()
389 * loop bound variables and cleanup attribute, supported by GCC and Clang.
390 */
391#define bpf_repeat(N) for ( \
392 /* initialize and define destructor */ \
393 struct bpf_iter_num ___it __attribute__((aligned(8), /* enforce, just in case */ \
394 cleanup(bpf_iter_num_destroy))), \
395 /* ___p pointer is necessary to call bpf_iter_num_new() *once* to init ___it */ \
396 *___p __attribute__((unused)) = ( \
397 bpf_iter_num_new(&___it, 0, (N)), \
398 /* this is a workaround for Clang bug: it currently doesn't emit BTF */ \
399 /* for bpf_iter_num_destroy() when used from cleanup() attribute */ \
400 (void)bpf_iter_num_destroy, (void *)0); \
401 bpf_iter_num_next(&___it); \
402 /* nothing here */ \
403)
404#endif /* bpf_repeat */
405
406#endif