kernel internals are subject to change and can break with newer kernels
such that the program needs to be adapted accordingly.
+Q: Are tracepoints part of the stable ABI?
+------------------------------------------
+A: NO. Tracepoints are tied to internal implementation details hence they are
+subject to change and can break with newer kernels. BPF programs need to change
+accordingly when this happens.
+
Q: How much stack space a BPF program uses?
-------------------------------------------
A: Currently all program types are limited to 512 bytes of stack
/* tracepoints with more than 12 arguments will hit build error */
#define CAST_TO_U64(...) CONCATENATE(__CAST, COUNT_ARGS(__VA_ARGS__))(__VA_ARGS__)
-#undef DECLARE_EVENT_CLASS
-#define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print) \
+#define __BPF_DECLARE_TRACE(call, proto, args) \
static notrace void \
__bpf_trace_##call(void *__data, proto) \
{ \
CONCATENATE(bpf_trace_run, COUNT_ARGS(args))(prog, CAST_TO_U64(args)); \
}
+#undef DECLARE_EVENT_CLASS
+#define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print) \
+ __BPF_DECLARE_TRACE(call, PARAMS(proto), PARAMS(args))
+
/*
* This part is compiled out, it is only here as a build time check
* to make sure that if the tracepoint handling changes, the
#define DEFINE_EVENT_PRINT(template, name, proto, args, print) \
DEFINE_EVENT(template, name, PARAMS(proto), PARAMS(args))
+#undef DECLARE_TRACE
+#define DECLARE_TRACE(call, proto, args) \
+ __BPF_DECLARE_TRACE(call, PARAMS(proto), PARAMS(args)) \
+ __DEFINE_EVENT(call, call, PARAMS(proto), PARAMS(args), 0)
+
#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
#undef DEFINE_EVENT_WRITABLE