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