diff options
| -rw-r--r-- | tools/lib/bpf/bpf_helpers.h | 103 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/progs/bpf_misc.h | 103 |
2 files changed, 103 insertions, 103 deletions
diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h index e7e1a8acc299..525dec66c129 100644 --- a/tools/lib/bpf/bpf_helpers.h +++ b/tools/lib/bpf/bpf_helpers.h @@ -291,4 +291,107 @@ enum libbpf_tristate { /* Helper macro to print out debug messages */ #define bpf_printk(fmt, args...) ___bpf_pick_printk(args)(fmt, ##args) +struct bpf_iter_num; + +extern int bpf_iter_num_new(struct bpf_iter_num *it, int start, int end) __ksym; +extern int *bpf_iter_num_next(struct bpf_iter_num *it) __ksym; +extern void bpf_iter_num_destroy(struct bpf_iter_num *it) __ksym; + +#ifndef bpf_for_each +/* bpf_for_each(iter_type, cur_elem, args...) provides generic construct for + * using BPF open-coded iterators without having to write mundane explicit + * low-level loop logic. Instead, it provides for()-like generic construct + * that can be used pretty naturally. E.g., for some hypothetical cgroup + * iterator, you'd write: + * + * struct cgroup *cg, *parent_cg = <...>; + * + * bpf_for_each(cgroup, cg, parent_cg, CG_ITER_CHILDREN) { + * bpf_printk("Child cgroup id = %d", cg->cgroup_id); + * if (cg->cgroup_id == 123) + * break; + * } + * + * I.e., it looks almost like high-level for each loop in other languages, + * supports continue/break, and is verifiable by BPF verifier. + * + * For iterating integers, the difference betwen bpf_for_each(num, i, N, M) + * and bpf_for(i, N, M) is in that bpf_for() provides additional proof to + * verifier that i is in [N, M) range, and in bpf_for_each() case i is `int + * *`, not just `int`. So for integers bpf_for() is more convenient. + * + * Note: this macro relies on C99 feature of allowing to declare variables + * inside for() loop, bound to for() loop lifetime. It also utilizes GCC + * extension: __attribute__((cleanup(<func>))), supported by both GCC and + * Clang. + */ +#define bpf_for_each(type, cur, args...) for ( \ + /* initialize and define destructor */ \ + struct bpf_iter_##type ___it __attribute__((aligned(8), /* enforce, just in case */, \ + cleanup(bpf_iter_##type##_destroy))), \ + /* ___p pointer is just to call bpf_iter_##type##_new() *once* to init ___it */ \ + *___p __attribute__((unused)) = ( \ + bpf_iter_##type##_new(&___it, ##args), \ + /* this is a workaround for Clang bug: it currently doesn't emit BTF */ \ + /* for bpf_iter_##type##_destroy() when used from cleanup() attribute */ \ + (void)bpf_iter_##type##_destroy, (void *)0); \ + /* iteration and termination check */ \ + (((cur) = bpf_iter_##type##_next(&___it))); \ +) +#endif /* bpf_for_each */ + +#ifndef bpf_for +/* bpf_for(i, start, end) implements a for()-like looping construct that sets + * provided integer variable *i* to values starting from *start* through, + * but not including, *end*. It also proves to BPF verifier that *i* belongs + * to range [start, end), so this can be used for accessing arrays without + * extra checks. + * + * Note: *start* and *end* are assumed to be expressions with no side effects + * and whose values do not change throughout bpf_for() loop execution. They do + * not have to be statically known or constant, though. + * + * Note: similarly to bpf_for_each(), it relies on C99 feature of declaring for() + * loop bound variables and cleanup attribute, supported by GCC and Clang. + */ +#define bpf_for(i, start, end) for ( \ + /* initialize and define destructor */ \ + struct bpf_iter_num ___it __attribute__((aligned(8), /* enforce, just in case */ \ + cleanup(bpf_iter_num_destroy))), \ + /* ___p pointer is necessary to call bpf_iter_num_new() *once* to init ___it */ \ + *___p __attribute__((unused)) = ( \ + bpf_iter_num_new(&___it, (start), (end)), \ + /* this is a workaround for Clang bug: it currently doesn't emit BTF */ \ + /* for bpf_iter_num_destroy() when used from cleanup() attribute */ \ + (void)bpf_iter_num_destroy, (void *)0); \ + ({ \ + /* iteration step */ \ + int *___t = bpf_iter_num_next(&___it); \ + /* termination and bounds check */ \ + (___t && ((i) = *___t, (i) >= (start) && (i) < (end))); \ + }); \ +) +#endif /* bpf_for */ + +#ifndef bpf_repeat +/* bpf_repeat(N) performs N iterations without exposing iteration number + * + * Note: similarly to bpf_for_each(), it relies on C99 feature of declaring for() + * loop bound variables and cleanup attribute, supported by GCC and Clang. + */ +#define bpf_repeat(N) for ( \ + /* initialize and define destructor */ \ + struct bpf_iter_num ___it __attribute__((aligned(8), /* enforce, just in case */ \ + cleanup(bpf_iter_num_destroy))), \ + /* ___p pointer is necessary to call bpf_iter_num_new() *once* to init ___it */ \ + *___p __attribute__((unused)) = ( \ + bpf_iter_num_new(&___it, 0, (N)), \ + /* this is a workaround for Clang bug: it currently doesn't emit BTF */ \ + /* for bpf_iter_num_destroy() when used from cleanup() attribute */ \ + (void)bpf_iter_num_destroy, (void *)0); \ + bpf_iter_num_next(&___it); \ + /* nothing here */ \ +) +#endif /* bpf_repeat */ + #endif diff --git a/tools/testing/selftests/bpf/progs/bpf_misc.h b/tools/testing/selftests/bpf/progs/bpf_misc.h index 6e3b4903c541..3b307de8dab9 100644 --- a/tools/testing/selftests/bpf/progs/bpf_misc.h +++ b/tools/testing/selftests/bpf/progs/bpf_misc.h @@ -121,107 +121,4 @@ /* make it look to compiler like value is read and written */ #define __sink(expr) asm volatile("" : "+g"(expr)) -struct bpf_iter_num; - -extern int bpf_iter_num_new(struct bpf_iter_num *it, int start, int end) __ksym; -extern int *bpf_iter_num_next(struct bpf_iter_num *it) __ksym; -extern void bpf_iter_num_destroy(struct bpf_iter_num *it) __ksym; - -#ifndef bpf_for_each -/* bpf_for_each(iter_type, cur_elem, args...) provides generic construct for - * using BPF open-coded iterators without having to write mundane explicit - * low-level loop logic. Instead, it provides for()-like generic construct - * that can be used pretty naturally. E.g., for some hypothetical cgroup - * iterator, you'd write: - * - * struct cgroup *cg, *parent_cg = <...>; - * - * bpf_for_each(cgroup, cg, parent_cg, CG_ITER_CHILDREN) { - * bpf_printk("Child cgroup id = %d", cg->cgroup_id); - * if (cg->cgroup_id == 123) - * break; - * } - * - * I.e., it looks almost like high-level for each loop in other languages, - * supports continue/break, and is verifiable by BPF verifier. - * - * For iterating integers, the difference betwen bpf_for_each(num, i, N, M) - * and bpf_for(i, N, M) is in that bpf_for() provides additional proof to - * verifier that i is in [N, M) range, and in bpf_for_each() case i is `int - * *`, not just `int`. So for integers bpf_for() is more convenient. - * - * Note: this macro relies on C99 feature of allowing to declare variables - * inside for() loop, bound to for() loop lifetime. It also utilizes GCC - * extension: __attribute__((cleanup(<func>))), supported by both GCC and - * Clang. - */ -#define bpf_for_each(type, cur, args...) for ( \ - /* initialize and define destructor */ \ - struct bpf_iter_##type ___it __attribute__((aligned(8), /* enforce, just in case */, \ - cleanup(bpf_iter_##type##_destroy))), \ - /* ___p pointer is just to call bpf_iter_##type##_new() *once* to init ___it */ \ - *___p __attribute__((unused)) = ( \ - bpf_iter_##type##_new(&___it, ##args), \ - /* this is a workaround for Clang bug: it currently doesn't emit BTF */ \ - /* for bpf_iter_##type##_destroy() when used from cleanup() attribute */ \ - (void)bpf_iter_##type##_destroy, (void *)0); \ - /* iteration and termination check */ \ - (((cur) = bpf_iter_##type##_next(&___it))); \ -) -#endif /* bpf_for_each */ - -#ifndef bpf_for -/* bpf_for(i, start, end) implements a for()-like looping construct that sets - * provided integer variable *i* to values starting from *start* through, - * but not including, *end*. It also proves to BPF verifier that *i* belongs - * to range [start, end), so this can be used for accessing arrays without - * extra checks. - * - * Note: *start* and *end* are assumed to be expressions with no side effects - * and whose values do not change throughout bpf_for() loop execution. They do - * not have to be statically known or constant, though. - * - * Note: similarly to bpf_for_each(), it relies on C99 feature of declaring for() - * loop bound variables and cleanup attribute, supported by GCC and Clang. - */ -#define bpf_for(i, start, end) for ( \ - /* initialize and define destructor */ \ - struct bpf_iter_num ___it __attribute__((aligned(8), /* enforce, just in case */ \ - cleanup(bpf_iter_num_destroy))), \ - /* ___p pointer is necessary to call bpf_iter_num_new() *once* to init ___it */ \ - *___p __attribute__((unused)) = ( \ - bpf_iter_num_new(&___it, (start), (end)), \ - /* this is a workaround for Clang bug: it currently doesn't emit BTF */ \ - /* for bpf_iter_num_destroy() when used from cleanup() attribute */ \ - (void)bpf_iter_num_destroy, (void *)0); \ - ({ \ - /* iteration step */ \ - int *___t = bpf_iter_num_next(&___it); \ - /* termination and bounds check */ \ - (___t && ((i) = *___t, (i) >= (start) && (i) < (end))); \ - }); \ -) -#endif /* bpf_for */ - -#ifndef bpf_repeat -/* bpf_repeat(N) performs N iterations without exposing iteration number - * - * Note: similarly to bpf_for_each(), it relies on C99 feature of declaring for() - * loop bound variables and cleanup attribute, supported by GCC and Clang. - */ -#define bpf_repeat(N) for ( \ - /* initialize and define destructor */ \ - struct bpf_iter_num ___it __attribute__((aligned(8), /* enforce, just in case */ \ - cleanup(bpf_iter_num_destroy))), \ - /* ___p pointer is necessary to call bpf_iter_num_new() *once* to init ___it */ \ - *___p __attribute__((unused)) = ( \ - bpf_iter_num_new(&___it, 0, (N)), \ - /* this is a workaround for Clang bug: it currently doesn't emit BTF */ \ - /* for bpf_iter_num_destroy() when used from cleanup() attribute */ \ - (void)bpf_iter_num_destroy, (void *)0); \ - bpf_iter_num_next(&___it); \ - /* nothing here */ \ -) -#endif /* bpf_repeat */ - #endif |