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 #ifndef __USER_EXIT_INFO_H
11 #define __USER_EXIT_INFO_H
12
13 enum uei_sizes {
14 UEI_REASON_LEN = 128,
15 UEI_MSG_LEN = 1024,
16 UEI_DUMP_DFL_LEN = 32768,
17 };
18
19 struct user_exit_info {
20 int kind;
21 s64 exit_code;
22 char reason[UEI_REASON_LEN];
23 char msg[UEI_MSG_LEN];
24 };
25
26 #ifdef __bpf__
27
28 #ifdef LSP
29 #include "../vmlinux/vmlinux.h"
30 #else
31 #include "vmlinux.h"
32 #endif
33 #include <bpf/bpf_core_read.h>
34
35 #define UEI_DEFINE(__name) \
36 char RESIZABLE_ARRAY(data, __name##_dump); \
37 const volatile u32 __name##_dump_len; \
38 struct user_exit_info __name SEC(".data")
39
40 #define UEI_RECORD(__uei_name, __ei) ({ \
41 bpf_probe_read_kernel_str(__uei_name.reason, \
42 sizeof(__uei_name.reason), (__ei)->reason); \
43 bpf_probe_read_kernel_str(__uei_name.msg, \
44 sizeof(__uei_name.msg), (__ei)->msg); \
45 bpf_probe_read_kernel_str(__uei_name##_dump, \
46 __uei_name##_dump_len, (__ei)->dump); \
47 if (bpf_core_field_exists((__ei)->exit_code)) \
48 __uei_name.exit_code = (__ei)->exit_code; \
49 /* use __sync to force memory barrier */ \
50 __sync_val_compare_and_swap(&__uei_name.kind, __uei_name.kind, \
51 (__ei)->kind); \
52 })
53
54 #else /* !__bpf__ */
55
56 #include <stdio.h>
57 #include <stdbool.h>
58
59 /* no need to call the following explicitly if SCX_OPS_LOAD() is used */
60 #define UEI_SET_SIZE(__skel, __ops_name, __uei_name) ({ \
61 u32 __len = (__skel)->struct_ops.__ops_name->exit_dump_len ?: UEI_DUMP_DFL_LEN; \
62 (__skel)->rodata->__uei_name##_dump_len = __len; \
63 RESIZE_ARRAY((__skel), data, __uei_name##_dump, __len); \
64 })
65
66 #define UEI_EXITED(__skel, __uei_name) ({ \
67 /* use __sync to force memory barrier */ \
68 __sync_val_compare_and_swap(&(__skel)->data->__uei_name.kind, -1, -1); \
69 })
70
71 #define UEI_REPORT(__skel, __uei_name) ({ \
72 struct user_exit_info *__uei = &(__skel)->data->__uei_name; \
73 char *__uei_dump = (__skel)->data_##__uei_name##_dump->__uei_name##_dump; \
74 if (__uei_dump[0] != '\0') { \
75 fputs("\nDEBUG DUMP\n", stderr); \
76 fputs("================================================================================\n\n", stderr); \
77 fputs(__uei_dump, stderr); \
78 fputs("\n================================================================================\n\n", stderr); \
79 } \
80 fprintf(stderr, "EXIT: %s", __uei->reason); \
81 if (__uei->msg[0] != '\0') \
82 fprintf(stderr, " (%s)", __uei->msg); \
83 fputs("\n", stderr); \
84 __uei->exit_code; \
85 })
86
87 /*
88 * We can't import vmlinux.h while compiling user C code. Let's duplicate
89 * scx_exit_code definition.
90 */
91 enum scx_exit_code {
92 /* Reasons */
93 SCX_ECODE_RSN_HOTPLUG = 1LLU << 32,
94
95 /* Actions */
96 SCX_ECODE_ACT_RESTART = 1LLU << 48,
97 };
98
99 enum uei_ecode_mask {
100 UEI_ECODE_USER_MASK = ((1LLU << 32) - 1),
101 UEI_ECODE_SYS_RSN_MASK = ((1LLU << 16) - 1) << 32,
102 UEI_ECODE_SYS_ACT_MASK = ((1LLU << 16) - 1) << 48,
103 };
104
105 /*
106 * These macro interpret the ecode returned from UEI_REPORT().
107 */
108 #define UEI_ECODE_USER(__ecode) ((__ecode) & UEI_ECODE_USER_MASK)
109 #define UEI_ECODE_SYS_RSN(__ecode) ((__ecode) & UEI_ECODE_SYS_RSN_MASK)
110 #define UEI_ECODE_SYS_ACT(__ecode) ((__ecode) & UEI_ECODE_SYS_ACT_MASK)
111
112 #define UEI_ECODE_RESTART(__ecode) (UEI_ECODE_SYS_ACT((__ecode)) == SCX_ECODE_ACT_RESTART)
113
114 #endif /* __bpf__ */
115 #endif /* __USER_EXIT_INFO_H */
116
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