xref: /linux/tools/sched_ext/include/scx/user_exit_info.bpf.h (revision a23cd25baed2316e50597f8b67192bdc904f955b)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * Define struct user_exit_info which is shared between BPF and userspace parts
4  * to communicate exit status and other information.
5  *
6  * Copyright (c) 2022 Meta Platforms, Inc. and affiliates.
7  * Copyright (c) 2022 Tejun Heo <tj@kernel.org>
8  * Copyright (c) 2022 David Vernet <dvernet@meta.com>
9  */
10 
11 #ifndef __USER_EXIT_INFO_BPF_H
12 #define __USER_EXIT_INFO_BPF_H
13 
14 #ifndef LSP
15 #include "vmlinux.h"
16 #endif
17 #include <bpf/bpf_core_read.h>
18 
19 #include "user_exit_info_common.h"
20 
21 #define UEI_DEFINE(__name)							\
22 	char RESIZABLE_ARRAY(data, __name##_dump);				\
23 	const volatile u32 __name##_dump_len;					\
24 	struct user_exit_info __name SEC(".data")
25 
26 #define UEI_RECORD(__uei_name, __ei) ({						\
27 	bpf_probe_read_kernel_str(__uei_name.reason,				\
28 				  sizeof(__uei_name.reason), (__ei)->reason);	\
29 	bpf_probe_read_kernel_str(__uei_name.msg,				\
30 				  sizeof(__uei_name.msg), (__ei)->msg);		\
31 	bpf_probe_read_kernel_str(__uei_name##_dump,				\
32 				  __uei_name##_dump_len, (__ei)->dump);		\
33 	if (bpf_core_field_exists((__ei)->exit_code))				\
34 		__uei_name.exit_code = (__ei)->exit_code;			\
35 	/* use __sync to force memory barrier */				\
36 	__sync_val_compare_and_swap(&__uei_name.kind, __uei_name.kind,		\
37 				    (__ei)->kind);				\
38 })
39 
40 #endif /* __USER_EXIT_INFO_BPF_H */
41