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d4dfc5700e
Instead of passing prog as an argument to bpf_trace_runX() helpers, that are called from tracepoint triggering calls, store BPF link itself (struct bpf_raw_tp_link for raw tracepoints). This will allow to pass extra information like BPF cookie into raw tracepoint registration. Instead of replacing `struct bpf_prog *prog = __data;` with corresponding `struct bpf_raw_tp_link *link = __data;` assignment in `__bpf_trace_##call` I just passed `__data` through into underlying bpf_trace_runX() call. This works well because we implicitly cast `void *`, and it also avoids naming clashes with arguments coming from tracepoint's "proto" list. We could have run into the same problem with "prog", we just happened to not have a tracepoint that has "prog" input argument. We are less lucky with "link", as there are tracepoints using "link" argument name already. So instead of trying to avoid naming conflicts, let's just remove intermediate local variable. It doesn't hurt readibility, it's either way a bit of a maze of calls and macros, that requires careful reading. Acked-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Message-ID: <20240319233852.1977493-3-andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
126 lines
4.3 KiB
C
126 lines
4.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#undef TRACE_SYSTEM_VAR
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#ifdef CONFIG_BPF_EVENTS
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#include "stages/stage6_event_callback.h"
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#undef __perf_count
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#define __perf_count(c) (c)
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#undef __perf_task
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#define __perf_task(t) (t)
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#include <linux/args.h>
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/* cast any integer, pointer, or small struct to u64 */
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#define UINTTYPE(size) \
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__typeof__(__builtin_choose_expr(size == 1, (u8)1, \
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__builtin_choose_expr(size == 2, (u16)2, \
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__builtin_choose_expr(size == 4, (u32)3, \
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__builtin_choose_expr(size == 8, (u64)4, \
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(void)5)))))
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#define __CAST_TO_U64(x) ({ \
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typeof(x) __src = (x); \
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UINTTYPE(sizeof(x)) __dst; \
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memcpy(&__dst, &__src, sizeof(__dst)); \
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(u64)__dst; })
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#define __CAST1(a,...) __CAST_TO_U64(a)
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#define __CAST2(a,...) __CAST_TO_U64(a), __CAST1(__VA_ARGS__)
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#define __CAST3(a,...) __CAST_TO_U64(a), __CAST2(__VA_ARGS__)
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#define __CAST4(a,...) __CAST_TO_U64(a), __CAST3(__VA_ARGS__)
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#define __CAST5(a,...) __CAST_TO_U64(a), __CAST4(__VA_ARGS__)
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#define __CAST6(a,...) __CAST_TO_U64(a), __CAST5(__VA_ARGS__)
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#define __CAST7(a,...) __CAST_TO_U64(a), __CAST6(__VA_ARGS__)
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#define __CAST8(a,...) __CAST_TO_U64(a), __CAST7(__VA_ARGS__)
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#define __CAST9(a,...) __CAST_TO_U64(a), __CAST8(__VA_ARGS__)
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#define __CAST10(a,...) __CAST_TO_U64(a), __CAST9(__VA_ARGS__)
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#define __CAST11(a,...) __CAST_TO_U64(a), __CAST10(__VA_ARGS__)
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#define __CAST12(a,...) __CAST_TO_U64(a), __CAST11(__VA_ARGS__)
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/* tracepoints with more than 12 arguments will hit build error */
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#define CAST_TO_U64(...) CONCATENATE(__CAST, COUNT_ARGS(__VA_ARGS__))(__VA_ARGS__)
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#define __BPF_DECLARE_TRACE(call, proto, args) \
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static notrace void \
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__bpf_trace_##call(void *__data, proto) \
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{ \
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CONCATENATE(bpf_trace_run, COUNT_ARGS(args))(__data, CAST_TO_U64(args)); \
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}
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#undef DECLARE_EVENT_CLASS
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#define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print) \
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__BPF_DECLARE_TRACE(call, PARAMS(proto), PARAMS(args))
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/*
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* This part is compiled out, it is only here as a build time check
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* to make sure that if the tracepoint handling changes, the
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* bpf probe will fail to compile unless it too is updated.
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*/
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#define __DEFINE_EVENT(template, call, proto, args, size) \
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static inline void bpf_test_probe_##call(void) \
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{ \
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check_trace_callback_type_##call(__bpf_trace_##template); \
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} \
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typedef void (*btf_trace_##call)(void *__data, proto); \
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static union { \
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struct bpf_raw_event_map event; \
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btf_trace_##call handler; \
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} __bpf_trace_tp_map_##call __used \
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__section("__bpf_raw_tp_map") = { \
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.event = { \
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.tp = &__tracepoint_##call, \
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.bpf_func = __bpf_trace_##template, \
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.num_args = COUNT_ARGS(args), \
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.writable_size = size, \
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}, \
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};
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#define FIRST(x, ...) x
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#define __CHECK_WRITABLE_BUF_SIZE(call, proto, args, size) \
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static inline void bpf_test_buffer_##call(void) \
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{ \
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/* BUILD_BUG_ON() is ignored if the code is completely eliminated, but \
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* BUILD_BUG_ON_ZERO() uses a different mechanism that is not \
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* dead-code-eliminated. \
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*/ \
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FIRST(proto); \
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(void)BUILD_BUG_ON_ZERO(size != sizeof(*FIRST(args))); \
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}
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#undef DEFINE_EVENT_WRITABLE
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#define DEFINE_EVENT_WRITABLE(template, call, proto, args, size) \
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__CHECK_WRITABLE_BUF_SIZE(call, PARAMS(proto), PARAMS(args), size) \
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__DEFINE_EVENT(template, call, PARAMS(proto), PARAMS(args), size)
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#undef DEFINE_EVENT
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#define DEFINE_EVENT(template, call, proto, args) \
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__DEFINE_EVENT(template, call, PARAMS(proto), PARAMS(args), 0)
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#undef DEFINE_EVENT_PRINT
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#define DEFINE_EVENT_PRINT(template, name, proto, args, print) \
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DEFINE_EVENT(template, name, PARAMS(proto), PARAMS(args))
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#undef DECLARE_TRACE
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#define DECLARE_TRACE(call, proto, args) \
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__BPF_DECLARE_TRACE(call, PARAMS(proto), PARAMS(args)) \
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__DEFINE_EVENT(call, call, PARAMS(proto), PARAMS(args), 0)
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#undef DECLARE_TRACE_WRITABLE
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#define DECLARE_TRACE_WRITABLE(call, proto, args, size) \
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__CHECK_WRITABLE_BUF_SIZE(call, PARAMS(proto), PARAMS(args), size) \
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__BPF_DECLARE_TRACE(call, PARAMS(proto), PARAMS(args)) \
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__DEFINE_EVENT(call, call, PARAMS(proto), PARAMS(args), size)
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#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
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#undef DECLARE_TRACE_WRITABLE
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#undef DEFINE_EVENT_WRITABLE
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#undef __CHECK_WRITABLE_BUF_SIZE
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#undef __DEFINE_EVENT
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#undef FIRST
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#endif /* CONFIG_BPF_EVENTS */
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