Re: [PATCH bpf-next v1 01/14] tools/bpf: Sync btf_ids.h to tools

On Mon Jun 1, 2026 at 6:17 PM EDT, Ihor Solodrai wrote:
> Sync tools/include/linux/btf_ids.h with include/linux/btf_ids.h so
> tools-side code can use BTF_ID_FLAGS(), BTF_SET8_START(), and
> BTF_KFUNCS_START().
>
> Keep the tools copy's existing compiler header dependency:
> tools/include/linux/compiler.h already provides __maybe_unused and
> tools/include/linux/compiler_attributes.h does not exist.
>
> Signed-off-by: Ihor Solodrai <[email protected]>

Reviewed-by: Emil Tsalapatis <[email protected]>

> ---
>  tools/include/linux/btf_ids.h | 78 ++++++++++++++++++++++++++++++++---
>  1 file changed, 73 insertions(+), 5 deletions(-)
>
> diff --git a/tools/include/linux/btf_ids.h b/tools/include/linux/btf_ids.h
> index 72ea363d434d..4fe5c5f1558c 100644
> --- a/tools/include/linux/btf_ids.h
> +++ b/tools/include/linux/btf_ids.h
> @@ -10,6 +10,9 @@ struct btf_id_set {
>  	u32 ids[];
>  };
>  
> +/* This flag implies BTF_SET8 holds kfunc(s) */
> +#define BTF_SET8_KFUNCS		(1 << 0)
> +
>  struct btf_id_set8 {
>  	u32 cnt;
>  	u32 flags;
> @@ -22,6 +25,7 @@ struct btf_id_set8 {
>  #ifdef CONFIG_DEBUG_INFO_BTF
>  
>  #include <linux/compiler.h> /* for __PASTE */
> +#include <linux/stringify.h>
>  
>  /*
>   * Following macros help to define lists of BTF IDs placed
> @@ -35,7 +39,7 @@ struct btf_id_set8 {
>  
>  #define BTF_IDS_SECTION ".BTF_ids"
>  
> -#define ____BTF_ID(symbol)				\
> +#define ____BTF_ID(symbol, word)			\
>  asm(							\
>  ".pushsection " BTF_IDS_SECTION ",\"a\";       \n"	\
>  ".local " #symbol " ;                          \n"	\
> @@ -43,10 +47,11 @@ asm(							\
>  ".size  " #symbol ", 4;                        \n"	\
>  #symbol ":                                     \n"	\
>  ".zero 4                                       \n"	\
> +word							\
>  ".popsection;                                  \n");
>  
> -#define __BTF_ID(symbol) \
> -	____BTF_ID(symbol)
> +#define __BTF_ID(symbol, word) \
> +	____BTF_ID(symbol, word)
>  
>  #define __ID(prefix) \
>  	__PASTE(__PASTE(prefix, __COUNTER__), __LINE__)
> @@ -56,7 +61,14 @@ asm(							\
>   * to 4 zero bytes.
>   */
>  #define BTF_ID(prefix, name) \
> -	__BTF_ID(__ID(__BTF_ID__##prefix##__##name##__))
> +	__BTF_ID(__ID(__BTF_ID__##prefix##__##name##__), "")
> +
> +#define ____BTF_ID_FLAGS(prefix, name, flags) \
> +	__BTF_ID(__ID(__BTF_ID__##prefix##__##name##__), ".long " #flags "\n")
> +#define __BTF_ID_FLAGS(prefix, name, flags, ...) \
> +	____BTF_ID_FLAGS(prefix, name, flags)
> +#define BTF_ID_FLAGS(prefix, name, ...) \
> +	__BTF_ID_FLAGS(prefix, name, ##__VA_ARGS__, 0)
>  
>  /*
>   * The BTF_ID_LIST macro defines pure (unsorted) list
> @@ -155,10 +167,58 @@ asm(							\
>  ".popsection;                                 \n");	\
>  extern struct btf_id_set name;
>  
> +/*
> + * The BTF_SET8_START/END macros pair defines sorted list of
> + * BTF IDs and their flags plus its members count, with the
> + * following layout:
> + *
> + * BTF_SET8_START(list)
> + * BTF_ID_FLAGS(type1, name1, flags)
> + * BTF_ID_FLAGS(type2, name2, flags)
> + * BTF_SET8_END(list)
> + *
> + * __BTF_ID__set8__list:
> + * .zero 8
> + * list:
> + * __BTF_ID__type1__name1__3:
> + * .zero 4
> + * .word (1 << 0) | (1 << 2)
> + * __BTF_ID__type2__name2__5:
> + * .zero 4
> + * .word (1 << 3) | (1 << 1) | (1 << 2)
> + *
> + */
> +#define __BTF_SET8_START(name, scope, flags)		\
> +__BTF_ID_LIST(name, local)				\
> +asm(							\
> +".pushsection " BTF_IDS_SECTION ",\"a\";       \n"	\
> +"." #scope " __BTF_ID__set8__" #name ";        \n"	\
> +"__BTF_ID__set8__" #name ":;                   \n"	\
> +".zero 4                                       \n"	\
> +".long " __stringify(flags)                   "\n"	\
> +".popsection;                                  \n");
> +
> +#define BTF_SET8_START(name)				\
> +__BTF_SET8_START(name, local, 0)
> +
> +#define BTF_SET8_END(name)				\
> +asm(							\
> +".pushsection " BTF_IDS_SECTION ",\"a\";      \n"	\
> +".size __BTF_ID__set8__" #name ", .-" #name "  \n"	\
> +".popsection;                                 \n");	\
> +extern struct btf_id_set8 name;
> +
> +#define BTF_KFUNCS_START(name)				\
> +__BTF_SET8_START(name, local, BTF_SET8_KFUNCS)
> +
> +#define BTF_KFUNCS_END(name)				\
> +BTF_SET8_END(name)
> +
>  #else
>  
> -#define BTF_ID_LIST(name) static u32 __maybe_unused name[5];
> +#define BTF_ID_LIST(name) static u32 __maybe_unused name[128];
>  #define BTF_ID(prefix, name)
> +#define BTF_ID_FLAGS(prefix, name, ...)
>  #define BTF_ID_UNUSED
>  #define BTF_ID_LIST_GLOBAL(name, n) u32 __maybe_unused name[n];
>  #define BTF_ID_LIST_SINGLE(name, prefix, typename) static u32 __maybe_unused name[1];
> @@ -166,6 +226,10 @@ extern struct btf_id_set name;
>  #define BTF_SET_START(name) static struct btf_id_set __maybe_unused name = { 0 };
>  #define BTF_SET_START_GLOBAL(name) static struct btf_id_set __maybe_unused name = { 0 };
>  #define BTF_SET_END(name)
> +#define BTF_SET8_START(name) static struct btf_id_set8 __maybe_unused name = { 0 };
> +#define BTF_SET8_END(name)
> +#define BTF_KFUNCS_START(name) static struct btf_id_set8 __maybe_unused name = { .flags = BTF_SET8_KFUNCS };
> +#define BTF_KFUNCS_END(name)
>  
>  #endif /* CONFIG_DEBUG_INFO_BTF */
>  
> @@ -215,5 +279,9 @@ MAX_BTF_TRACING_TYPE,
>  };
>  
>  extern u32 btf_tracing_ids[];
> +extern u32 bpf_cgroup_btf_id[];
> +extern u32 bpf_local_storage_map_btf_id[];
> +extern u32 btf_bpf_map_id[];
> +extern u32 bpf_kmem_cache_btf_id[];
>  
>  #endif