Merge branch 'libbpf: Move CO-RE logic into separate file.' (793eccae) · Commits · EulixOS / Software / Kernel

tools/lib/bpf/Build

+1 −1

Original line number	Original line	Diff line number	Diff line
	libbpf-y := libbpf.o bpf.o nlattr.o btf.o libbpf_errno.o str_error.o \		libbpf-y := libbpf.o bpf.o nlattr.o btf.o libbpf_errno.o str_error.o \
	netlink.o bpf_prog_linfo.o libbpf_probes.o xsk.o hashmap.o \		netlink.o bpf_prog_linfo.o libbpf_probes.o xsk.o hashmap.o \
	btf_dump.o ringbuf.o strset.o linker.o gen_loader.o		btf_dump.o ringbuf.o strset.o linker.o gen_loader.o relo_core.o

libbpf-y := libbpf.o bpf.o nlattr.o btf.o libbpf_errno.o str_error.o \

libbpf-y := libbpf.o bpf.o nlattr.o btf.o libbpf_errno.o str_error.o \

	    netlink.o bpf_prog_linfo.o libbpf_probes.o xsk.o hashmap.o \

	    netlink.o bpf_prog_linfo.o libbpf_probes.o xsk.o hashmap.o \

	    btf_dump.o ringbuf.o strset.o linker.o gen_loader.o

	    btf_dump.o ringbuf.o strset.o linker.o gen_loader.o relo_core.o

tools/lib/bpf/libbpf.c

+33 −1311

File changed.

Preview size limit exceeded, changes collapsed.

tools/lib/bpf/libbpf_internal.h

+11 −70

Original line number	Original line	Diff line number	Diff line
	@@ -14,6 +14,7 @@
	#include <errno.h>		#include <errno.h>
	#include <linux/err.h>		#include <linux/err.h>
	#include "libbpf_legacy.h"		#include "libbpf_legacy.h"
			#include "relo_core.h"

	/* make sure libbpf doesn't use kernel-only integer typedefs */		/* make sure libbpf doesn't use kernel-only integer typedefs */
	#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64		#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
	@@ -366,76 +367,6 @@ struct bpf_line_info_min {
	__u32 line_col;		__u32 line_col;
	};		};

	/* bpf_core_relo_kind encodes which aspect of captured field/type/enum value
	* has to be adjusted by relocations.
	*/
	enum bpf_core_relo_kind {
	BPF_FIELD_BYTE_OFFSET = 0, /* field byte offset */
	BPF_FIELD_BYTE_SIZE = 1, /* field size in bytes */
	BPF_FIELD_EXISTS = 2, /* field existence in target kernel */
	BPF_FIELD_SIGNED = 3, /* field signedness (0 - unsigned, 1 - signed) */
	BPF_FIELD_LSHIFT_U64 = 4, /* bitfield-specific left bitshift */
	BPF_FIELD_RSHIFT_U64 = 5, /* bitfield-specific right bitshift */
	BPF_TYPE_ID_LOCAL = 6, /* type ID in local BPF object */
	BPF_TYPE_ID_TARGET = 7, /* type ID in target kernel */
	BPF_TYPE_EXISTS = 8, /* type existence in target kernel */
	BPF_TYPE_SIZE = 9, /* type size in bytes */
	BPF_ENUMVAL_EXISTS = 10, /* enum value existence in target kernel */
	BPF_ENUMVAL_VALUE = 11, /* enum value integer value */
	};

	/* The minimum bpf_core_relo checked by the loader
	*
	* CO-RE relocation captures the following data:
	* - insn_off - instruction offset (in bytes) within a BPF program that needs
	* its insn->imm field to be relocated with actual field info;
	* - type_id - BTF type ID of the "root" (containing) entity of a relocatable
	* type or field;
	* - access_str_off - offset into corresponding .BTF string section. String
	* interpretation depends on specific relocation kind:
	* - for field-based relocations, string encodes an accessed field using
	* a sequence of field and array indices, separated by colon (:). It's
	* conceptually very close to LLVM's getelementptr ([0]) instruction's
	* arguments for identifying offset to a field.
	* - for type-based relocations, strings is expected to be just "0";
	* - for enum value-based relocations, string contains an index of enum
	* value within its enum type;
	*
	* Example to provide a better feel.
	*
	* struct sample {
	* int a;
	* struct {
	* int b[10];
	* };
	* };
	*
	* struct sample *s = ...;
	* int x = &s->a; // encoded as "0:0" (a is field #0)
	* int y = &s->b[5]; // encoded as "0:1:0:5" (anon struct is field #1,
	* // b is field #0 inside anon struct, accessing elem #5)
	* int z = &s[10]->b; // encoded as "10:1" (ptr is used as an array)
	*
	* type_id for all relocs in this example will capture BTF type id of
	* `struct sample`.
	*
	* Such relocation is emitted when using __builtin_preserve_access_index()
	* Clang built-in, passing expression that captures field address, e.g.:
	*
	* bpf_probe_read(&dst, sizeof(dst),
	* __builtin_preserve_access_index(&src->a.b.c));
	*
	* In this case Clang will emit field relocation recording necessary data to
	* be able to find offset of embedded `a.b.c` field within `src` struct.
	*
	* [0] https://llvm.org/docs/LangRef.html#getelementptr-instruction
	*/
	struct bpf_core_relo {
	__u32 insn_off;
	__u32 type_id;
	__u32 access_str_off;
	enum bpf_core_relo_kind kind;
	};

	typedef int (type_id_visit_fn)(__u32 type_id, void *ctx);		typedef int (type_id_visit_fn)(__u32 type_id, void *ctx);
	typedef int (str_off_visit_fn)(__u32 str_off, void *ctx);		typedef int (str_off_visit_fn)(__u32 str_off, void *ctx);
	@@ -494,4 +425,14 @@ static inline void libbpf_ptr(void ret)
	return ret;		return ret;
	}		}

			static inline bool str_is_empty(const char *s)
			{
			return !s \|\| !s[0];
			}

			static inline bool is_ldimm64_insn(struct bpf_insn *insn)
			{
			return insn->code == (BPF_LD \| BPF_IMM \| BPF_DW);
			}

	#endif /* __LIBBPF_LIBBPF_INTERNAL_H */		#endif /* __LIBBPF_LIBBPF_INTERNAL_H */

tools/lib/bpf/relo_core.c

0 → 100644

+1295 −0

File added.

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tools/lib/bpf/relo_core.h

0 → 100644

+100 −0

Original line number	Original line	Diff line number	Diff line
			/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
			/* Copyright (c) 2019 Facebook */

			#ifndef __RELO_CORE_H
			#define __RELO_CORE_H

			/* bpf_core_relo_kind encodes which aspect of captured field/type/enum value
			* has to be adjusted by relocations.
			*/
			enum bpf_core_relo_kind {
			BPF_FIELD_BYTE_OFFSET = 0, /* field byte offset */
			BPF_FIELD_BYTE_SIZE = 1, /* field size in bytes */
			BPF_FIELD_EXISTS = 2, /* field existence in target kernel */
			BPF_FIELD_SIGNED = 3, /* field signedness (0 - unsigned, 1 - signed) */
			BPF_FIELD_LSHIFT_U64 = 4, /* bitfield-specific left bitshift */
			BPF_FIELD_RSHIFT_U64 = 5, /* bitfield-specific right bitshift */
			BPF_TYPE_ID_LOCAL = 6, /* type ID in local BPF object */
			BPF_TYPE_ID_TARGET = 7, /* type ID in target kernel */
			BPF_TYPE_EXISTS = 8, /* type existence in target kernel */
			BPF_TYPE_SIZE = 9, /* type size in bytes */
			BPF_ENUMVAL_EXISTS = 10, /* enum value existence in target kernel */
			BPF_ENUMVAL_VALUE = 11, /* enum value integer value */
			};

			/* The minimum bpf_core_relo checked by the loader
			*
			* CO-RE relocation captures the following data:
			* - insn_off - instruction offset (in bytes) within a BPF program that needs
			* its insn->imm field to be relocated with actual field info;
			* - type_id - BTF type ID of the "root" (containing) entity of a relocatable
			* type or field;
			* - access_str_off - offset into corresponding .BTF string section. String
			* interpretation depends on specific relocation kind:
			* - for field-based relocations, string encodes an accessed field using
			* a sequence of field and array indices, separated by colon (:). It's
			* conceptually very close to LLVM's getelementptr ([0]) instruction's
			* arguments for identifying offset to a field.
			* - for type-based relocations, strings is expected to be just "0";
			* - for enum value-based relocations, string contains an index of enum
			* value within its enum type;
			*
			* Example to provide a better feel.
			*
			* struct sample {
			* int a;
			* struct {
			* int b[10];
			* };
			* };
			*
			* struct sample *s = ...;
			* int x = &s->a; // encoded as "0:0" (a is field #0)
			* int y = &s->b[5]; // encoded as "0:1:0:5" (anon struct is field #1,
			* // b is field #0 inside anon struct, accessing elem #5)
			* int z = &s[10]->b; // encoded as "10:1" (ptr is used as an array)
			*
			* type_id for all relocs in this example will capture BTF type id of
			* `struct sample`.
			*
			* Such relocation is emitted when using __builtin_preserve_access_index()
			* Clang built-in, passing expression that captures field address, e.g.:
			*
			* bpf_probe_read(&dst, sizeof(dst),
			* __builtin_preserve_access_index(&src->a.b.c));
			*
			* In this case Clang will emit field relocation recording necessary data to
			* be able to find offset of embedded `a.b.c` field within `src` struct.
			*
			* [0] https://llvm.org/docs/LangRef.html#getelementptr-instruction
			*/
			struct bpf_core_relo {
			__u32 insn_off;
			__u32 type_id;
			__u32 access_str_off;
			enum bpf_core_relo_kind kind;
			};

			struct bpf_core_cand {
			const struct btf *btf;
			const struct btf_type *t;
			const char *name;
			__u32 id;
			};

			/* dynamically sized list of type IDs and its associated struct btf */
			struct bpf_core_cand_list {
			struct bpf_core_cand *cands;
			int len;
			};

			int bpf_core_apply_relo_insn(const char *prog_name,
			struct bpf_insn *insn, int insn_idx,
			const struct bpf_core_relo *relo, int relo_idx,
			const struct btf *local_btf,
			struct bpf_core_cand_list *cands);
			int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id,
			const struct btf *targ_btf, __u32 targ_id);

			size_t bpf_core_essential_name_len(const char *name);
			#endif