mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-12 13:55:32 +00:00
![Jiri Olsa](/assets/img/avatar_default.png)
Adding support to generate .BTF_ids section that will hold BTF ID lists for verifier. Adding macros that will help to define lists of BTF ID values placed in .BTF_ids section. They are initially filled with zeros (during compilation) and resolved later during the linking phase by resolve_btfids tool. Following defines list of one BTF ID value: BTF_ID_LIST(bpf_skb_output_btf_ids) BTF_ID(struct, sk_buff) It also defines following variable to access the list: extern u32 bpf_skb_output_btf_ids[]; The BTF_ID_UNUSED macro defines 4 zero bytes. It's used when we want to define 'unused' entry in BTF_ID_LIST, like: BTF_ID_LIST(bpf_skb_output_btf_ids) BTF_ID(struct, sk_buff) BTF_ID_UNUSED BTF_ID(struct, task_struct) Suggested-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Tested-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200711215329.41165-4-jolsa@kernel.org
87 lines
2.2 KiB
C
87 lines
2.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
|
|
#ifndef _LINUX_BTF_IDS_H
|
|
#define _LINUX_BTF_IDS_H
|
|
|
|
#include <linux/compiler.h> /* for __PASTE */
|
|
|
|
/*
|
|
* Following macros help to define lists of BTF IDs placed
|
|
* in .BTF_ids section. They are initially filled with zeros
|
|
* (during compilation) and resolved later during the
|
|
* linking phase by resolve_btfids tool.
|
|
*
|
|
* Any change in list layout must be reflected in resolve_btfids
|
|
* tool logic.
|
|
*/
|
|
|
|
#define BTF_IDS_SECTION ".BTF_ids"
|
|
|
|
#define ____BTF_ID(symbol) \
|
|
asm( \
|
|
".pushsection " BTF_IDS_SECTION ",\"a\"; \n" \
|
|
".local " #symbol " ; \n" \
|
|
".type " #symbol ", @object; \n" \
|
|
".size " #symbol ", 4; \n" \
|
|
#symbol ": \n" \
|
|
".zero 4 \n" \
|
|
".popsection; \n");
|
|
|
|
#define __BTF_ID(symbol) \
|
|
____BTF_ID(symbol)
|
|
|
|
#define __ID(prefix) \
|
|
__PASTE(prefix, __COUNTER__)
|
|
|
|
/*
|
|
* The BTF_ID defines unique symbol for each ID pointing
|
|
* to 4 zero bytes.
|
|
*/
|
|
#define BTF_ID(prefix, name) \
|
|
__BTF_ID(__ID(__BTF_ID__##prefix##__##name##__))
|
|
|
|
/*
|
|
* The BTF_ID_LIST macro defines pure (unsorted) list
|
|
* of BTF IDs, with following layout:
|
|
*
|
|
* BTF_ID_LIST(list1)
|
|
* BTF_ID(type1, name1)
|
|
* BTF_ID(type2, name2)
|
|
*
|
|
* list1:
|
|
* __BTF_ID__type1__name1__1:
|
|
* .zero 4
|
|
* __BTF_ID__type2__name2__2:
|
|
* .zero 4
|
|
*
|
|
*/
|
|
#define __BTF_ID_LIST(name) \
|
|
asm( \
|
|
".pushsection " BTF_IDS_SECTION ",\"a\"; \n" \
|
|
".local " #name "; \n" \
|
|
#name ":; \n" \
|
|
".popsection; \n"); \
|
|
|
|
#define BTF_ID_LIST(name) \
|
|
__BTF_ID_LIST(name) \
|
|
extern u32 name[];
|
|
|
|
/*
|
|
* The BTF_ID_UNUSED macro defines 4 zero bytes.
|
|
* It's used when we want to define 'unused' entry
|
|
* in BTF_ID_LIST, like:
|
|
*
|
|
* BTF_ID_LIST(bpf_skb_output_btf_ids)
|
|
* BTF_ID(struct, sk_buff)
|
|
* BTF_ID_UNUSED
|
|
* BTF_ID(struct, task_struct)
|
|
*/
|
|
|
|
#define BTF_ID_UNUSED \
|
|
asm( \
|
|
".pushsection " BTF_IDS_SECTION ",\"a\"; \n" \
|
|
".zero 4 \n" \
|
|
".popsection; \n");
|
|
|
|
|
|
#endif
|