samples/bpf: convert to vmlinux.h with tracing programs

This commit replaces separate headers with a single vmlinux.h to
tracing programs. Thanks to that, we no longer need to define the
argument structure for tracing programs directly. For example, argument
for the sched_switch tracpepoint (sched_switch_args) can be replaced
with the vmlinux.h provided trace_event_raw_sched_switch.

Additional defines have been added to the BPF program either directly
or through the inclusion of net_shared.h. Defined values are
PERF_MAX_STACK_DEPTH, IFNAMSIZ constants and __stringify() macro. This
change enables the BPF program to access internal structures with BTF
generated "vmlinux.h" header.

Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Link: https://lore.kernel.org/r/20230818090119.477441-3-danieltimlee@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 6 insertions, 15 deletions

diff --git a/samples/bpf/offwaketime_kern.c b/samples/bpf/offwaketime_kern.c
index 23f12b47e9e5..8e5105811178 100644
--- a/samples/bpf/offwaketime_kern.c
+++ b/samples/bpf/offwaketime_kern.c
@@ -4,14 +4,15 @@
  * modify it under the terms of version 2 of the GNU General Public
  * License as published by the Free Software Foundation.
  */
-#include <uapi/linux/bpf.h>
-#include <uapi/linux/ptrace.h>
-#include <uapi/linux/perf_event.h>
+#include "vmlinux.h"
 #include <linux/version.h>
-#include <linux/sched.h>
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_tracing.h>
 
+#ifndef PERF_MAX_STACK_DEPTH
+#define PERF_MAX_STACK_DEPTH         127
+#endif
+
 #define _(P)                                                                   \
 	({                                                                     \
 		typeof(P) val;                                                 \
@@ -111,18 +112,8 @@ static inline int update_counts(void *ctx, u32 pid, u64 delta)
 
 #if 1
 /* taken from /sys/kernel/tracing/events/sched/sched_switch/format */
-struct sched_switch_args {
-	unsigned long long pad;
-	char prev_comm[TASK_COMM_LEN];
-	int prev_pid;
-	int prev_prio;
-	long long prev_state;
-	char next_comm[TASK_COMM_LEN];
-	int next_pid;
-	int next_prio;
-};
 SEC("tracepoint/sched/sched_switch")
-int oncpu(struct sched_switch_args *ctx)
+int oncpu(struct trace_event_raw_sched_switch *ctx)
 {
 	/* record previous thread sleep time */
 	u32 pid = ctx->prev_pid;