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linux/tools/lib/bpf/bpf_gen_internal.h

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libbpf: Generate loader program out of BPF ELF file. The BPF program loading process performed by libbpf is quite complex and consists of the following steps: "open" phase: - parse elf file and remember relocations, sections - collect externs and ksyms including their btf_ids in prog's BTF - patch BTF datasec (since llvm couldn't do it) - init maps (old style map_def, BTF based, global data map, kconfig map) - collect relocations against progs and maps "load" phase: - probe kernel features - load vmlinux BTF - resolve externs (kconfig and ksym) - load program BTF - init struct_ops - create maps - apply CO-RE relocations - patch ld_imm64 insns with src_reg=PSEUDO_MAP, PSEUDO_MAP_VALUE, PSEUDO_BTF_ID - reposition subprograms and adjust call insns - sanitize and load progs During this process libbpf does sys_bpf() calls to load BTF, create maps, populate maps and finally load programs. Instead of actually doing the syscalls generate a trace of what libbpf would have done and represent it as the "loader program". The "loader program" consists of single map with: - union bpf_attr(s) - BTF bytes - map value bytes - insns bytes and single bpf program that passes bpf_attr(s) and data into bpf_sys_bpf() helper. Executing such "loader program" via bpf_prog_test_run() command will replay the sequence of syscalls that libbpf would have done which will result the same maps created and programs loaded as specified in the elf file. The "loader program" removes libelf and majority of libbpf dependency from program loading process. kconfig, typeless ksym, struct_ops and CO-RE are not supported yet. The order of relocate_data and relocate_calls had to change, so that bpf_gen__prog_load() can see all relocations for a given program with correct insn_idx-es. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210514003623.28033-15-alexei.starovoitov@gmail.com
2021-05-14 00:36:16 +00:00
/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
/* Copyright (c) 2021 Facebook */
#ifndef __BPF_GEN_INTERNAL_H
#define __BPF_GEN_INTERNAL_H
libbpf: Unify low-level BPF_PROG_LOAD APIs into bpf_prog_load() Add a new unified OPTS-based low-level API for program loading, bpf_prog_load() ([0]). bpf_prog_load() accepts few "mandatory" parameters as input arguments (program type, name, license, instructions) and all the other optional (as in not required to specify for all types of BPF programs) fields into struct bpf_prog_load_opts. This makes all the other non-extensible APIs variant for BPF_PROG_LOAD obsolete and they are slated for deprecation in libbpf v0.7: - bpf_load_program(); - bpf_load_program_xattr(); - bpf_verify_program(). Implementation-wise, internal helper libbpf__bpf_prog_load is refactored to become a public bpf_prog_load() API. struct bpf_prog_load_params used internally is replaced by public struct bpf_prog_load_opts. Unfortunately, while conceptually all this is pretty straightforward, the biggest complication comes from the already existing bpf_prog_load() *high-level* API, which has nothing to do with BPF_PROG_LOAD command. We try really hard to have a new API named bpf_prog_load(), though, because it maps naturally to BPF_PROG_LOAD command. For that, we rename old bpf_prog_load() into bpf_prog_load_deprecated() and mark it as COMPAT_VERSION() for shared library users compiled against old version of libbpf. Statically linked users and shared lib users compiled against new version of libbpf headers will get "rerouted" to bpf_prog_deprecated() through a macro helper that decides whether to use new or old bpf_prog_load() based on number of input arguments (see ___libbpf_overload in libbpf_common.h). To test that existing bpf_prog_load()-using code compiles and works as expected, I've compiled and ran selftests as is. I had to remove (locally) selftest/bpf/Makefile -Dbpf_prog_load=bpf_prog_test_load hack because it was conflicting with the macro-based overload approach. I don't expect anyone else to do something like this in practice, though. This is testing-specific way to replace bpf_prog_load() calls with special testing variant of it, which adds extra prog_flags value. After testing I kept this selftests hack, but ensured that we use a new bpf_prog_load_deprecated name for this. This patch also marks bpf_prog_load() and bpf_prog_load_xattr() as deprecated. bpf_object interface has to be used for working with struct bpf_program. Libbpf doesn't support loading just a bpf_program. The silver lining is that when we get to libbpf 1.0 all these complication will be gone and we'll have one clean bpf_prog_load() low-level API with no backwards compatibility hackery surrounding it. [0] Closes: https://github.com/libbpf/libbpf/issues/284 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211103220845.2676888-4-andrii@kernel.org
2021-11-03 22:08:36 +00:00
#include "bpf.h"
libbpf: Generate loader program out of BPF ELF file. The BPF program loading process performed by libbpf is quite complex and consists of the following steps: "open" phase: - parse elf file and remember relocations, sections - collect externs and ksyms including their btf_ids in prog's BTF - patch BTF datasec (since llvm couldn't do it) - init maps (old style map_def, BTF based, global data map, kconfig map) - collect relocations against progs and maps "load" phase: - probe kernel features - load vmlinux BTF - resolve externs (kconfig and ksym) - load program BTF - init struct_ops - create maps - apply CO-RE relocations - patch ld_imm64 insns with src_reg=PSEUDO_MAP, PSEUDO_MAP_VALUE, PSEUDO_BTF_ID - reposition subprograms and adjust call insns - sanitize and load progs During this process libbpf does sys_bpf() calls to load BTF, create maps, populate maps and finally load programs. Instead of actually doing the syscalls generate a trace of what libbpf would have done and represent it as the "loader program". The "loader program" consists of single map with: - union bpf_attr(s) - BTF bytes - map value bytes - insns bytes and single bpf program that passes bpf_attr(s) and data into bpf_sys_bpf() helper. Executing such "loader program" via bpf_prog_test_run() command will replay the sequence of syscalls that libbpf would have done which will result the same maps created and programs loaded as specified in the elf file. The "loader program" removes libelf and majority of libbpf dependency from program loading process. kconfig, typeless ksym, struct_ops and CO-RE are not supported yet. The order of relocate_data and relocate_calls had to change, so that bpf_gen__prog_load() can see all relocations for a given program with correct insn_idx-es. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210514003623.28033-15-alexei.starovoitov@gmail.com
2021-05-14 00:36:16 +00:00
struct ksym_relo_desc {
const char *name;
int kind;
int insn_idx;
libbpf: Update gen_loader to emit BTF_KIND_FUNC relocations This change updates the BPF syscall loader to relocate BTF_KIND_FUNC relocations, with support for weak kfunc relocations. The general idea is to move map_fds to loader map, and also use the data for storing kfunc BTF fds. Since both reuse the fd_array parameter, they need to be kept together. For map_fds, we reserve MAX_USED_MAPS slots in a region, and for kfunc, we reserve MAX_KFUNC_DESCS. This is done so that insn->off has more chances of being <= INT16_MAX than treating data map as a sparse array and adding fd as needed. When the MAX_KFUNC_DESCS limit is reached, we fall back to the sparse array model, so that as long as it does remain <= INT16_MAX, we pass an index relative to the start of fd_array. We store all ksyms in an array where we try to avoid calling the bpf_btf_find_by_name_kind helper, and also reuse the BTF fd that was already stored. This also speeds up the loading process compared to emitting calls in all cases, in later tests. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211002011757.311265-9-memxor@gmail.com
2021-10-02 01:17:56 +00:00
bool is_weak;
libbpf: Add typeless ksym support to gen_loader This uses the bpf_kallsyms_lookup_name helper added in previous patches to relocate typeless ksyms. The return value ENOENT can be ignored, and the value written to 'res' can be directly stored to the insn, as it is overwritten to 0 on lookup failure. For repeating symbols, we can simply copy the previously populated bpf_insn. Also, we need to take care to not close fds for typeless ksym_desc, so reuse the 'off' member's space to add a marker for typeless ksym and use that to skip them in cleanup_relos. We add a emit_ksym_relo_log helper that avoids duplicating common logging instructions between typeless and weak ksym (for future commit). Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211028063501.2239335-3-memxor@gmail.com
2021-10-28 06:34:55 +00:00
bool is_typeless;
libbpf: Update gen_loader to emit BTF_KIND_FUNC relocations This change updates the BPF syscall loader to relocate BTF_KIND_FUNC relocations, with support for weak kfunc relocations. The general idea is to move map_fds to loader map, and also use the data for storing kfunc BTF fds. Since both reuse the fd_array parameter, they need to be kept together. For map_fds, we reserve MAX_USED_MAPS slots in a region, and for kfunc, we reserve MAX_KFUNC_DESCS. This is done so that insn->off has more chances of being <= INT16_MAX than treating data map as a sparse array and adding fd as needed. When the MAX_KFUNC_DESCS limit is reached, we fall back to the sparse array model, so that as long as it does remain <= INT16_MAX, we pass an index relative to the start of fd_array. We store all ksyms in an array where we try to avoid calling the bpf_btf_find_by_name_kind helper, and also reuse the BTF fd that was already stored. This also speeds up the loading process compared to emitting calls in all cases, in later tests. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211002011757.311265-9-memxor@gmail.com
2021-10-02 01:17:56 +00:00
};
struct ksym_desc {
const char *name;
int ref;
int kind;
libbpf: Add typeless ksym support to gen_loader This uses the bpf_kallsyms_lookup_name helper added in previous patches to relocate typeless ksyms. The return value ENOENT can be ignored, and the value written to 'res' can be directly stored to the insn, as it is overwritten to 0 on lookup failure. For repeating symbols, we can simply copy the previously populated bpf_insn. Also, we need to take care to not close fds for typeless ksym_desc, so reuse the 'off' member's space to add a marker for typeless ksym and use that to skip them in cleanup_relos. We add a emit_ksym_relo_log helper that avoids duplicating common logging instructions between typeless and weak ksym (for future commit). Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211028063501.2239335-3-memxor@gmail.com
2021-10-28 06:34:55 +00:00
union {
/* used for kfunc */
int off;
/* used for typeless ksym */
bool typeless;
};
libbpf: Update gen_loader to emit BTF_KIND_FUNC relocations This change updates the BPF syscall loader to relocate BTF_KIND_FUNC relocations, with support for weak kfunc relocations. The general idea is to move map_fds to loader map, and also use the data for storing kfunc BTF fds. Since both reuse the fd_array parameter, they need to be kept together. For map_fds, we reserve MAX_USED_MAPS slots in a region, and for kfunc, we reserve MAX_KFUNC_DESCS. This is done so that insn->off has more chances of being <= INT16_MAX than treating data map as a sparse array and adding fd as needed. When the MAX_KFUNC_DESCS limit is reached, we fall back to the sparse array model, so that as long as it does remain <= INT16_MAX, we pass an index relative to the start of fd_array. We store all ksyms in an array where we try to avoid calling the bpf_btf_find_by_name_kind helper, and also reuse the BTF fd that was already stored. This also speeds up the loading process compared to emitting calls in all cases, in later tests. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211002011757.311265-9-memxor@gmail.com
2021-10-02 01:17:56 +00:00
int insn;
libbpf: Generate loader program out of BPF ELF file. The BPF program loading process performed by libbpf is quite complex and consists of the following steps: "open" phase: - parse elf file and remember relocations, sections - collect externs and ksyms including their btf_ids in prog's BTF - patch BTF datasec (since llvm couldn't do it) - init maps (old style map_def, BTF based, global data map, kconfig map) - collect relocations against progs and maps "load" phase: - probe kernel features - load vmlinux BTF - resolve externs (kconfig and ksym) - load program BTF - init struct_ops - create maps - apply CO-RE relocations - patch ld_imm64 insns with src_reg=PSEUDO_MAP, PSEUDO_MAP_VALUE, PSEUDO_BTF_ID - reposition subprograms and adjust call insns - sanitize and load progs During this process libbpf does sys_bpf() calls to load BTF, create maps, populate maps and finally load programs. Instead of actually doing the syscalls generate a trace of what libbpf would have done and represent it as the "loader program". The "loader program" consists of single map with: - union bpf_attr(s) - BTF bytes - map value bytes - insns bytes and single bpf program that passes bpf_attr(s) and data into bpf_sys_bpf() helper. Executing such "loader program" via bpf_prog_test_run() command will replay the sequence of syscalls that libbpf would have done which will result the same maps created and programs loaded as specified in the elf file. The "loader program" removes libelf and majority of libbpf dependency from program loading process. kconfig, typeless ksym, struct_ops and CO-RE are not supported yet. The order of relocate_data and relocate_calls had to change, so that bpf_gen__prog_load() can see all relocations for a given program with correct insn_idx-es. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210514003623.28033-15-alexei.starovoitov@gmail.com
2021-05-14 00:36:16 +00:00
};
struct bpf_gen {
struct gen_loader_opts *opts;
void *data_start;
void *data_cur;
void *insn_start;
void *insn_cur;
libbpf: Cleanup temp FDs when intermediate sys_bpf fails. Fix loader program to close temporary FDs when intermediate sys_bpf command fails. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210514003623.28033-16-alexei.starovoitov@gmail.com
2021-05-14 00:36:17 +00:00
ssize_t cleanup_label;
libbpf: Generate loader program out of BPF ELF file. The BPF program loading process performed by libbpf is quite complex and consists of the following steps: "open" phase: - parse elf file and remember relocations, sections - collect externs and ksyms including their btf_ids in prog's BTF - patch BTF datasec (since llvm couldn't do it) - init maps (old style map_def, BTF based, global data map, kconfig map) - collect relocations against progs and maps "load" phase: - probe kernel features - load vmlinux BTF - resolve externs (kconfig and ksym) - load program BTF - init struct_ops - create maps - apply CO-RE relocations - patch ld_imm64 insns with src_reg=PSEUDO_MAP, PSEUDO_MAP_VALUE, PSEUDO_BTF_ID - reposition subprograms and adjust call insns - sanitize and load progs During this process libbpf does sys_bpf() calls to load BTF, create maps, populate maps and finally load programs. Instead of actually doing the syscalls generate a trace of what libbpf would have done and represent it as the "loader program". The "loader program" consists of single map with: - union bpf_attr(s) - BTF bytes - map value bytes - insns bytes and single bpf program that passes bpf_attr(s) and data into bpf_sys_bpf() helper. Executing such "loader program" via bpf_prog_test_run() command will replay the sequence of syscalls that libbpf would have done which will result the same maps created and programs loaded as specified in the elf file. The "loader program" removes libelf and majority of libbpf dependency from program loading process. kconfig, typeless ksym, struct_ops and CO-RE are not supported yet. The order of relocate_data and relocate_calls had to change, so that bpf_gen__prog_load() can see all relocations for a given program with correct insn_idx-es. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210514003623.28033-15-alexei.starovoitov@gmail.com
2021-05-14 00:36:16 +00:00
__u32 nr_progs;
__u32 nr_maps;
int log_level;
int error;
struct ksym_relo_desc *relos;
int relo_cnt;
libbpf: Use CO-RE in the kernel in light skeleton. Without lskel the CO-RE relocations are processed by libbpf before any other work is done. Instead, when lskel is needed, remember relocation as RELO_CORE kind. Then when loader prog is generated for a given bpf program pass CO-RE relos of that program to gen loader via bpf_gen__record_relo_core(). The gen loader will remember them as-is and pass it later as-is into the kernel. The normal libbpf flow is to process CO-RE early before call relos happen. In case of gen_loader the core relos have to be added to other relos to be copied together when bpf static function is appended in different places to other main bpf progs. During the copy the append_subprog_relos() will adjust insn_idx for normal relos and for RELO_CORE kind too. When that is done each struct reloc_desc has good relos for specific main prog. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211201181040.23337-10-alexei.starovoitov@gmail.com
2021-12-01 18:10:32 +00:00
struct bpf_core_relo *core_relos;
int core_relo_cnt;
libbpf: Generate loader program out of BPF ELF file. The BPF program loading process performed by libbpf is quite complex and consists of the following steps: "open" phase: - parse elf file and remember relocations, sections - collect externs and ksyms including their btf_ids in prog's BTF - patch BTF datasec (since llvm couldn't do it) - init maps (old style map_def, BTF based, global data map, kconfig map) - collect relocations against progs and maps "load" phase: - probe kernel features - load vmlinux BTF - resolve externs (kconfig and ksym) - load program BTF - init struct_ops - create maps - apply CO-RE relocations - patch ld_imm64 insns with src_reg=PSEUDO_MAP, PSEUDO_MAP_VALUE, PSEUDO_BTF_ID - reposition subprograms and adjust call insns - sanitize and load progs During this process libbpf does sys_bpf() calls to load BTF, create maps, populate maps and finally load programs. Instead of actually doing the syscalls generate a trace of what libbpf would have done and represent it as the "loader program". The "loader program" consists of single map with: - union bpf_attr(s) - BTF bytes - map value bytes - insns bytes and single bpf program that passes bpf_attr(s) and data into bpf_sys_bpf() helper. Executing such "loader program" via bpf_prog_test_run() command will replay the sequence of syscalls that libbpf would have done which will result the same maps created and programs loaded as specified in the elf file. The "loader program" removes libelf and majority of libbpf dependency from program loading process. kconfig, typeless ksym, struct_ops and CO-RE are not supported yet. The order of relocate_data and relocate_calls had to change, so that bpf_gen__prog_load() can see all relocations for a given program with correct insn_idx-es. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210514003623.28033-15-alexei.starovoitov@gmail.com
2021-05-14 00:36:16 +00:00
char attach_target[128];
int attach_kind;
libbpf: Update gen_loader to emit BTF_KIND_FUNC relocations This change updates the BPF syscall loader to relocate BTF_KIND_FUNC relocations, with support for weak kfunc relocations. The general idea is to move map_fds to loader map, and also use the data for storing kfunc BTF fds. Since both reuse the fd_array parameter, they need to be kept together. For map_fds, we reserve MAX_USED_MAPS slots in a region, and for kfunc, we reserve MAX_KFUNC_DESCS. This is done so that insn->off has more chances of being <= INT16_MAX than treating data map as a sparse array and adding fd as needed. When the MAX_KFUNC_DESCS limit is reached, we fall back to the sparse array model, so that as long as it does remain <= INT16_MAX, we pass an index relative to the start of fd_array. We store all ksyms in an array where we try to avoid calling the bpf_btf_find_by_name_kind helper, and also reuse the BTF fd that was already stored. This also speeds up the loading process compared to emitting calls in all cases, in later tests. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211002011757.311265-9-memxor@gmail.com
2021-10-02 01:17:56 +00:00
struct ksym_desc *ksyms;
__u32 nr_ksyms;
int fd_array;
int nr_fd_array;
libbpf: Generate loader program out of BPF ELF file. The BPF program loading process performed by libbpf is quite complex and consists of the following steps: "open" phase: - parse elf file and remember relocations, sections - collect externs and ksyms including their btf_ids in prog's BTF - patch BTF datasec (since llvm couldn't do it) - init maps (old style map_def, BTF based, global data map, kconfig map) - collect relocations against progs and maps "load" phase: - probe kernel features - load vmlinux BTF - resolve externs (kconfig and ksym) - load program BTF - init struct_ops - create maps - apply CO-RE relocations - patch ld_imm64 insns with src_reg=PSEUDO_MAP, PSEUDO_MAP_VALUE, PSEUDO_BTF_ID - reposition subprograms and adjust call insns - sanitize and load progs During this process libbpf does sys_bpf() calls to load BTF, create maps, populate maps and finally load programs. Instead of actually doing the syscalls generate a trace of what libbpf would have done and represent it as the "loader program". The "loader program" consists of single map with: - union bpf_attr(s) - BTF bytes - map value bytes - insns bytes and single bpf program that passes bpf_attr(s) and data into bpf_sys_bpf() helper. Executing such "loader program" via bpf_prog_test_run() command will replay the sequence of syscalls that libbpf would have done which will result the same maps created and programs loaded as specified in the elf file. The "loader program" removes libelf and majority of libbpf dependency from program loading process. kconfig, typeless ksym, struct_ops and CO-RE are not supported yet. The order of relocate_data and relocate_calls had to change, so that bpf_gen__prog_load() can see all relocations for a given program with correct insn_idx-es. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210514003623.28033-15-alexei.starovoitov@gmail.com
2021-05-14 00:36:16 +00:00
};
void bpf_gen__init(struct bpf_gen *gen, int log_level);
int bpf_gen__finish(struct bpf_gen *gen);
void bpf_gen__free(struct bpf_gen *gen);
void bpf_gen__load_btf(struct bpf_gen *gen, const void *raw_data, __u32 raw_size);
libbpf: Unify low-level map creation APIs w/ new bpf_map_create() Mark the entire zoo of low-level map creation APIs for deprecation in libbpf 0.7 ([0]) and introduce a new bpf_map_create() API that is OPTS-based (and thus future-proof) and matches the BPF_MAP_CREATE command name. While at it, ensure that gen_loader sends map_extra field. Also remove now unneeded btf_key_type_id/btf_value_type_id logic that libbpf is doing anyways. [0] Closes: https://github.com/libbpf/libbpf/issues/282 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211124193233.3115996-2-andrii@kernel.org
2021-11-24 19:32:30 +00:00
void bpf_gen__map_create(struct bpf_gen *gen,
enum bpf_map_type map_type, const char *map_name,
__u32 key_size, __u32 value_size, __u32 max_entries,
struct bpf_map_create_opts *map_attr, int map_idx);
libbpf: Unify low-level BPF_PROG_LOAD APIs into bpf_prog_load() Add a new unified OPTS-based low-level API for program loading, bpf_prog_load() ([0]). bpf_prog_load() accepts few "mandatory" parameters as input arguments (program type, name, license, instructions) and all the other optional (as in not required to specify for all types of BPF programs) fields into struct bpf_prog_load_opts. This makes all the other non-extensible APIs variant for BPF_PROG_LOAD obsolete and they are slated for deprecation in libbpf v0.7: - bpf_load_program(); - bpf_load_program_xattr(); - bpf_verify_program(). Implementation-wise, internal helper libbpf__bpf_prog_load is refactored to become a public bpf_prog_load() API. struct bpf_prog_load_params used internally is replaced by public struct bpf_prog_load_opts. Unfortunately, while conceptually all this is pretty straightforward, the biggest complication comes from the already existing bpf_prog_load() *high-level* API, which has nothing to do with BPF_PROG_LOAD command. We try really hard to have a new API named bpf_prog_load(), though, because it maps naturally to BPF_PROG_LOAD command. For that, we rename old bpf_prog_load() into bpf_prog_load_deprecated() and mark it as COMPAT_VERSION() for shared library users compiled against old version of libbpf. Statically linked users and shared lib users compiled against new version of libbpf headers will get "rerouted" to bpf_prog_deprecated() through a macro helper that decides whether to use new or old bpf_prog_load() based on number of input arguments (see ___libbpf_overload in libbpf_common.h). To test that existing bpf_prog_load()-using code compiles and works as expected, I've compiled and ran selftests as is. I had to remove (locally) selftest/bpf/Makefile -Dbpf_prog_load=bpf_prog_test_load hack because it was conflicting with the macro-based overload approach. I don't expect anyone else to do something like this in practice, though. This is testing-specific way to replace bpf_prog_load() calls with special testing variant of it, which adds extra prog_flags value. After testing I kept this selftests hack, but ensured that we use a new bpf_prog_load_deprecated name for this. This patch also marks bpf_prog_load() and bpf_prog_load_xattr() as deprecated. bpf_object interface has to be used for working with struct bpf_program. Libbpf doesn't support loading just a bpf_program. The silver lining is that when we get to libbpf 1.0 all these complication will be gone and we'll have one clean bpf_prog_load() low-level API with no backwards compatibility hackery surrounding it. [0] Closes: https://github.com/libbpf/libbpf/issues/284 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211103220845.2676888-4-andrii@kernel.org
2021-11-03 22:08:36 +00:00
void bpf_gen__prog_load(struct bpf_gen *gen,
enum bpf_prog_type prog_type, const char *prog_name,
const char *license, struct bpf_insn *insns, size_t insn_cnt,
struct bpf_prog_load_opts *load_attr, int prog_idx);
libbpf: Generate loader program out of BPF ELF file. The BPF program loading process performed by libbpf is quite complex and consists of the following steps: "open" phase: - parse elf file and remember relocations, sections - collect externs and ksyms including their btf_ids in prog's BTF - patch BTF datasec (since llvm couldn't do it) - init maps (old style map_def, BTF based, global data map, kconfig map) - collect relocations against progs and maps "load" phase: - probe kernel features - load vmlinux BTF - resolve externs (kconfig and ksym) - load program BTF - init struct_ops - create maps - apply CO-RE relocations - patch ld_imm64 insns with src_reg=PSEUDO_MAP, PSEUDO_MAP_VALUE, PSEUDO_BTF_ID - reposition subprograms and adjust call insns - sanitize and load progs During this process libbpf does sys_bpf() calls to load BTF, create maps, populate maps and finally load programs. Instead of actually doing the syscalls generate a trace of what libbpf would have done and represent it as the "loader program". The "loader program" consists of single map with: - union bpf_attr(s) - BTF bytes - map value bytes - insns bytes and single bpf program that passes bpf_attr(s) and data into bpf_sys_bpf() helper. Executing such "loader program" via bpf_prog_test_run() command will replay the sequence of syscalls that libbpf would have done which will result the same maps created and programs loaded as specified in the elf file. The "loader program" removes libelf and majority of libbpf dependency from program loading process. kconfig, typeless ksym, struct_ops and CO-RE are not supported yet. The order of relocate_data and relocate_calls had to change, so that bpf_gen__prog_load() can see all relocations for a given program with correct insn_idx-es. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210514003623.28033-15-alexei.starovoitov@gmail.com
2021-05-14 00:36:16 +00:00
void bpf_gen__map_update_elem(struct bpf_gen *gen, int map_idx, void *value, __u32 value_size);
void bpf_gen__map_freeze(struct bpf_gen *gen, int map_idx);
void bpf_gen__record_attach_target(struct bpf_gen *gen, const char *name, enum bpf_attach_type type);
libbpf: Add typeless ksym support to gen_loader This uses the bpf_kallsyms_lookup_name helper added in previous patches to relocate typeless ksyms. The return value ENOENT can be ignored, and the value written to 'res' can be directly stored to the insn, as it is overwritten to 0 on lookup failure. For repeating symbols, we can simply copy the previously populated bpf_insn. Also, we need to take care to not close fds for typeless ksym_desc, so reuse the 'off' member's space to add a marker for typeless ksym and use that to skip them in cleanup_relos. We add a emit_ksym_relo_log helper that avoids duplicating common logging instructions between typeless and weak ksym (for future commit). Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211028063501.2239335-3-memxor@gmail.com
2021-10-28 06:34:55 +00:00
void bpf_gen__record_extern(struct bpf_gen *gen, const char *name, bool is_weak,
bool is_typeless, int kind, int insn_idx);
libbpf: Use CO-RE in the kernel in light skeleton. Without lskel the CO-RE relocations are processed by libbpf before any other work is done. Instead, when lskel is needed, remember relocation as RELO_CORE kind. Then when loader prog is generated for a given bpf program pass CO-RE relos of that program to gen loader via bpf_gen__record_relo_core(). The gen loader will remember them as-is and pass it later as-is into the kernel. The normal libbpf flow is to process CO-RE early before call relos happen. In case of gen_loader the core relos have to be added to other relos to be copied together when bpf static function is appended in different places to other main bpf progs. During the copy the append_subprog_relos() will adjust insn_idx for normal relos and for RELO_CORE kind too. When that is done each struct reloc_desc has good relos for specific main prog. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211201181040.23337-10-alexei.starovoitov@gmail.com
2021-12-01 18:10:32 +00:00
void bpf_gen__record_relo_core(struct bpf_gen *gen, const struct bpf_core_relo *core_relo);
libbpf: Generate loader program out of BPF ELF file. The BPF program loading process performed by libbpf is quite complex and consists of the following steps: "open" phase: - parse elf file and remember relocations, sections - collect externs and ksyms including their btf_ids in prog's BTF - patch BTF datasec (since llvm couldn't do it) - init maps (old style map_def, BTF based, global data map, kconfig map) - collect relocations against progs and maps "load" phase: - probe kernel features - load vmlinux BTF - resolve externs (kconfig and ksym) - load program BTF - init struct_ops - create maps - apply CO-RE relocations - patch ld_imm64 insns with src_reg=PSEUDO_MAP, PSEUDO_MAP_VALUE, PSEUDO_BTF_ID - reposition subprograms and adjust call insns - sanitize and load progs During this process libbpf does sys_bpf() calls to load BTF, create maps, populate maps and finally load programs. Instead of actually doing the syscalls generate a trace of what libbpf would have done and represent it as the "loader program". The "loader program" consists of single map with: - union bpf_attr(s) - BTF bytes - map value bytes - insns bytes and single bpf program that passes bpf_attr(s) and data into bpf_sys_bpf() helper. Executing such "loader program" via bpf_prog_test_run() command will replay the sequence of syscalls that libbpf would have done which will result the same maps created and programs loaded as specified in the elf file. The "loader program" removes libelf and majority of libbpf dependency from program loading process. kconfig, typeless ksym, struct_ops and CO-RE are not supported yet. The order of relocate_data and relocate_calls had to change, so that bpf_gen__prog_load() can see all relocations for a given program with correct insn_idx-es. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210514003623.28033-15-alexei.starovoitov@gmail.com
2021-05-14 00:36:16 +00:00
#endif
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