1 /* SPDX-License-Identifier: GPL-2.0 */ 2 3 #ifndef _LINUX_BTF_IDS_H 4 #define _LINUX_BTF_IDS_H 5 6 #ifdef CONFIG_DEBUG_INFO_BTF 7 8 #include <linux/compiler.h> /* for __PASTE */ 9 10 /* 11 * Following macros help to define lists of BTF IDs placed 12 * in .BTF_ids section. They are initially filled with zeros 13 * (during compilation) and resolved later during the 14 * linking phase by resolve_btfids tool. 15 * 16 * Any change in list layout must be reflected in resolve_btfids 17 * tool logic. 18 */ 19 20 #define BTF_IDS_SECTION ".BTF_ids" 21 22 #define ____BTF_ID(symbol) \ 23 asm( \ 24 ".pushsection " BTF_IDS_SECTION ",\"a\"; \n" \ 25 ".local " #symbol " ; \n" \ 26 ".type " #symbol ", STT_OBJECT; \n" \ 27 ".size " #symbol ", 4; \n" \ 28 #symbol ": \n" \ 29 ".zero 4 \n" \ 30 ".popsection; \n"); 31 32 #define __BTF_ID(symbol) \ 33 ____BTF_ID(symbol) 34 35 #define __ID(prefix) \ 36 __PASTE(prefix, __COUNTER__) 37 38 /* 39 * The BTF_ID defines unique symbol for each ID pointing 40 * to 4 zero bytes. 41 */ 42 #define BTF_ID(prefix, name) \ 43 __BTF_ID(__ID(__BTF_ID__##prefix##__##name##__)) 44 45 /* 46 * The BTF_ID_LIST macro defines pure (unsorted) list 47 * of BTF IDs, with following layout: 48 * 49 * BTF_ID_LIST(list1) 50 * BTF_ID(type1, name1) 51 * BTF_ID(type2, name2) 52 * 53 * list1: 54 * __BTF_ID__type1__name1__1: 55 * .zero 4 56 * __BTF_ID__type2__name2__2: 57 * .zero 4 58 * 59 */ 60 #define __BTF_ID_LIST(name) \ 61 asm( \ 62 ".pushsection " BTF_IDS_SECTION ",\"a\"; \n" \ 63 ".local " #name "; \n" \ 64 #name ":; \n" \ 65 ".popsection; \n"); \ 66 67 #define BTF_ID_LIST(name) \ 68 __BTF_ID_LIST(name) \ 69 extern u32 name[]; 70 71 /* 72 * The BTF_ID_UNUSED macro defines 4 zero bytes. 73 * It's used when we want to define 'unused' entry 74 * in BTF_ID_LIST, like: 75 * 76 * BTF_ID_LIST(bpf_skb_output_btf_ids) 77 * BTF_ID(struct, sk_buff) 78 * BTF_ID_UNUSED 79 * BTF_ID(struct, task_struct) 80 */ 81 82 #define BTF_ID_UNUSED \ 83 asm( \ 84 ".pushsection " BTF_IDS_SECTION ",\"a\"; \n" \ 85 ".zero 4 \n" \ 86 ".popsection; \n"); 87 88 #else 89 90 #define BTF_ID_LIST(name) static u32 name[5]; 91 #define BTF_ID(prefix, name) 92 #define BTF_ID_UNUSED 93 94 #endif /* CONFIG_DEBUG_INFO_BTF */ 95 96 #endif 97