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/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
#ifndef __BPF_HELPERS__
#define __BPF_HELPERS__
/*
* Note that bpf programs need to include either
* vmlinux.h (auto-generated from BTF) or linux/types.h
* in advance since bpf_helper_defs.h uses such types
* as __u64.
*/
#include "bpf_helper_defs.h"
#define __uint(name, val) int (*name)[val]
#define __type(name, val) typeof(val) *name
#define __array(name, val) typeof(val) *name[]
/* Helper macro to print out debug messages */
#define bpf_printk(fmt, ...) \
({ \
char ____fmt[] = fmt; \
bpf_trace_printk(____fmt, sizeof(____fmt), \
##__VA_ARGS__); \
})
/*
* Helper macro to place programs, maps, license in
* different sections in elf_bpf file. Section names
* are interpreted by libbpf depending on the context (BPF programs, BPF maps,
* extern variables, etc).
* To allow use of SEC() with externs (e.g., for extern .maps declarations),
* make sure __attribute__((unused)) doesn't trigger compilation warning.
*/
#define SEC(name) \
_Pragma("GCC diagnostic push") \
_Pragma("GCC diagnostic ignored \"-Wignored-attributes\"") \
__attribute__((section(name), used)) \
_Pragma("GCC diagnostic pop") \
/* Avoid 'linux/stddef.h' definition of '__always_inline'. */
#undef __always_inline
#define __always_inline inline __attribute__((always_inline))
#ifndef __noinline
#define __noinline __attribute__((noinline))
#endif
#ifndef __weak
#define __weak __attribute__((weak))
#endif
/*
* Use __hidden attribute to mark a non-static BPF subprogram effectively
* static for BPF verifier's verification algorithm purposes, allowing more
* extensive and permissive BPF verification process, taking into account
* subprogram's caller context.
*/
#define __hidden __attribute__((visibility("hidden")))
/* When utilizing vmlinux.h with BPF CO-RE, user BPF programs can't include
* any system-level headers (such as stddef.h, linux/version.h, etc), and
* commonly-used macros like NULL and KERNEL_VERSION aren't available through
* vmlinux.h. This just adds unnecessary hurdles and forces users to re-define
* them on their own. So as a convenience, provide such definitions here.
*/
#ifndef NULL
#define NULL ((void *)0)
#endif
#ifndef KERNEL_VERSION
#define KERNEL_VERSION(a, b, c) (((a) << 16) + ((b) << 8) + ((c) > 255 ? 255 : (c)))
#endif
/*
* Helper macros to manipulate data structures
*/
#ifndef offsetof
#define offsetof(TYPE, MEMBER) ((unsigned long)&((TYPE *)0)->MEMBER)
#endif
#ifndef container_of
#define container_of(ptr, type, member) \
({ \
void *__mptr = (void *)(ptr); \
((type *)(__mptr - offsetof(type, member))); \
})
#endif
/*
* Helper macro to throw a compilation error if __bpf_unreachable() gets
* built into the resulting code. This works given BPF back end does not
* implement __builtin_trap(). This is useful to assert that certain paths
* of the program code are never used and hence eliminated by the compiler.
*
* For example, consider a switch statement that covers known cases used by
* the program. __bpf_unreachable() can then reside in the default case. If
* the program gets extended such that a case is not covered in the switch
* statement, then it will throw a build error due to the default case not
* being compiled out.
*/
#ifndef __bpf_unreachable
# define __bpf_unreachable() __builtin_trap()
#endif
/*
* Helper function to perform a tail call with a constant/immediate map slot.
*/
#if __clang_major__ >= 8 && defined(__bpf__)
static __always_inline void
bpf_tail_call_static(void *ctx, const void *map, const __u32 slot)
{
if (!__builtin_constant_p(slot))
__bpf_unreachable();
/*
* Provide a hard guarantee that LLVM won't optimize setting r2 (map
* pointer) and r3 (constant map index) from _different paths_ ending
* up at the _same_ call insn as otherwise we won't be able to use the
* jmpq/nopl retpoline-free patching by the x86-64 JIT in the kernel
* given they mismatch. See also d2e4c1e6c294 ("bpf: Constant map key
* tracking for prog array pokes") for details on verifier tracking.
*
* Note on clobber list: we need to stay in-line with BPF calling
* convention, so even if we don't end up using r0, r4, r5, we need
* to mark them as clobber so that LLVM doesn't end up using them
* before / after the call.
*/
asm volatile("r1 = %[ctx]\n\t"
"r2 = %[map]\n\t"
"r3 = %[slot]\n\t"
"call 12"
:: [ctx]"r"(ctx), [map]"r"(map), [slot]"i"(slot)
: "r0", "r1", "r2", "r3", "r4", "r5");
}
#endif
/*
* Helper structure used by eBPF C program
* to describe BPF map attributes to libbpf loader
*/
struct bpf_map_def {
unsigned int type;
unsigned int key_size;
unsigned int value_size;
unsigned int max_entries;
unsigned int map_flags;
};
enum libbpf_pin_type {
LIBBPF_PIN_NONE,
/* PIN_BY_NAME: pin maps by name (in /sys/fs/bpf by default) */
LIBBPF_PIN_BY_NAME,
};
enum libbpf_tristate {
TRI_NO = 0,
TRI_YES = 1,
TRI_MODULE = 2,
};
#define __kconfig __attribute__((section(".kconfig")))
#define __ksym __attribute__((section(".ksyms")))
#endif
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