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 18 enum uei_sizes { 19 UEI_REASON_LEN = 128, 20 UEI_MSG_LEN = 1024, 21 UEI_DUMP_DFL_LEN = 32768, 22 }; 23 24 struct 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 */ 94 enum scx_exit_code { 95 /* Reasons */ 96 SCX_ECODE_RSN_HOTPLUG = 1LLU << 32, 97 98 /* Actions */ 99 SCX_ECODE_ACT_RESTART = 1LLU << 48, 100 }; 101 102 enum 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 */ 119