1 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ 2 #ifndef __BPF_HELPERS__ 3 #define __BPF_HELPERS__ 4 5 /* 6 * Note that bpf programs need to include either 7 * vmlinux.h (auto-generated from BTF) or linux/types.h 8 * in advance since bpf_helper_defs.h uses such types 9 * as __u64. 10 */ 11 #include "bpf_helper_defs.h" 12 13 #define __uint(name, val) int (*name)[val] 14 #define __type(name, val) typeof(val) *name 15 #define __array(name, val) typeof(val) *name[] 16 17 /* Helper macro to print out debug messages */ 18 #define bpf_printk(fmt, ...) \ 19 ({ \ 20 char ____fmt[] = fmt; \ 21 bpf_trace_printk(____fmt, sizeof(____fmt), \ 22 ##__VA_ARGS__); \ 23 }) 24 25 /* 26 * Helper macro to place programs, maps, license in 27 * different sections in elf_bpf file. Section names 28 * are interpreted by elf_bpf loader 29 */ 30 #define SEC(NAME) __attribute__((section(NAME), used)) 31 32 #ifndef __always_inline 33 #define __always_inline __attribute__((always_inline)) 34 #endif 35 #ifndef __noinline 36 #define __noinline __attribute__((noinline)) 37 #endif 38 #ifndef __weak 39 #define __weak __attribute__((weak)) 40 #endif 41 42 /* 43 * Helper macro to manipulate data structures 44 */ 45 #ifndef offsetof 46 #define offsetof(TYPE, MEMBER) ((unsigned long)&((TYPE *)0)->MEMBER) 47 #endif 48 #ifndef container_of 49 #define container_of(ptr, type, member) \ 50 ({ \ 51 void *__mptr = (void *)(ptr); \ 52 ((type *)(__mptr - offsetof(type, member))); \ 53 }) 54 #endif 55 56 /* 57 * Helper macro to throw a compilation error if __bpf_unreachable() gets 58 * built into the resulting code. This works given BPF back end does not 59 * implement __builtin_trap(). This is useful to assert that certain paths 60 * of the program code are never used and hence eliminated by the compiler. 61 * 62 * For example, consider a switch statement that covers known cases used by 63 * the program. __bpf_unreachable() can then reside in the default case. If 64 * the program gets extended such that a case is not covered in the switch 65 * statement, then it will throw a build error due to the default case not 66 * being compiled out. 67 */ 68 #ifndef __bpf_unreachable 69 # define __bpf_unreachable() __builtin_trap() 70 #endif 71 72 /* 73 * Helper function to perform a tail call with a constant/immediate map slot. 74 */ 75 #if __clang_major__ >= 8 && defined(__bpf__) 76 static __always_inline void 77 bpf_tail_call_static(void *ctx, const void *map, const __u32 slot) 78 { 79 if (!__builtin_constant_p(slot)) 80 __bpf_unreachable(); 81 82 /* 83 * Provide a hard guarantee that LLVM won't optimize setting r2 (map 84 * pointer) and r3 (constant map index) from _different paths_ ending 85 * up at the _same_ call insn as otherwise we won't be able to use the 86 * jmpq/nopl retpoline-free patching by the x86-64 JIT in the kernel 87 * given they mismatch. See also d2e4c1e6c294 ("bpf: Constant map key 88 * tracking for prog array pokes") for details on verifier tracking. 89 * 90 * Note on clobber list: we need to stay in-line with BPF calling 91 * convention, so even if we don't end up using r0, r4, r5, we need 92 * to mark them as clobber so that LLVM doesn't end up using them 93 * before / after the call. 94 */ 95 asm volatile("r1 = %[ctx]\n\t" 96 "r2 = %[map]\n\t" 97 "r3 = %[slot]\n\t" 98 "call 12" 99 :: [ctx]"r"(ctx), [map]"r"(map), [slot]"i"(slot) 100 : "r0", "r1", "r2", "r3", "r4", "r5"); 101 } 102 #endif 103 104 /* 105 * Helper structure used by eBPF C program 106 * to describe BPF map attributes to libbpf loader 107 */ 108 struct bpf_map_def { 109 unsigned int type; 110 unsigned int key_size; 111 unsigned int value_size; 112 unsigned int max_entries; 113 unsigned int map_flags; 114 }; 115 116 enum libbpf_pin_type { 117 LIBBPF_PIN_NONE, 118 /* PIN_BY_NAME: pin maps by name (in /sys/fs/bpf by default) */ 119 LIBBPF_PIN_BY_NAME, 120 }; 121 122 enum libbpf_tristate { 123 TRI_NO = 0, 124 TRI_YES = 1, 125 TRI_MODULE = 2, 126 }; 127 128 #define __kconfig __attribute__((section(".kconfig"))) 129 #define __ksym __attribute__((section(".ksyms"))) 130 131 #endif 132