OpenE2K/dwarves
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity
407693e2ca
dwarves/libbtf.h

70 lines
2.2 KiB
C
Raw Normal View History

Adopt SPDX-License-Identifier Signed-off-by: Domenico Andreoli <domenico.andreoli@linux.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-01-15 18:28:24 +01:00
/*
SPDX-License-Identifier: GPL-2.0-only
Fixup copyright notices for BTF files authored by Facebook engineers Cc: Andrii Nakryiko <andriin@fb.com> Cc: Domenico Andreoli <domenico.andreoli@linux.com> Cc: Yonghong Song <yhs@fb.com> Signed-off-by: Martin Lau <kafai@fb.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-01-18 19:42:37 +01:00
Copyright (C) 2019 Facebook
Adopt SPDX-License-Identifier Signed-off-by: Domenico Andreoli <domenico.andreoli@linux.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-01-15 18:28:24 +01:00
*/
btf: Add BTF support This patch introduces BPF Type Format (BTF). BTF (BPF Type Format) is the meta data format which describes the data types of BPF program/map. Hence, it basically focus on the C programming language which the modern BPF is primary using. The first use case is to provide a generic pretty print capability for a BPF map. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-03-06 01:53:50 +01:00
#ifndef _LIBBTF_H
#define _LIBBTF_H
#include "gobuffer.h"
btf: Fix bitfield encoding The btf bitfield encoding is broken. For the following example: -bash-4.2$ cat t.c struct t { int a:2; int b:1; int :3; int c:1; int d; char e:1; char f:1; int g; }; void test(struct t *t) { return; } -bash-4.2$ clang -S -g -emit-llvm t.c The output for bpf "little and big" endian results with pahole dwarf2btf conversion: -bash-4.2$ llc -march=bpfel -mattr=dwarfris -filetype=obj t.ll -bash-4.2$ pahole -JV t.o [1] PTR (anon) type_id=2 [2] STRUCT t size=16 vlen=7 a type_id=5 bits_offset=30 b type_id=6 bits_offset=29 c type_id=6 bits_offset=25 d type_id=3 bits_offset=32 e type_id=7 bits_offset=71 f type_id=7 bits_offset=70 g type_id=3 bits_offset=96 [3] INT int size=4 bit_offset=0 nr_bits=32 encoding=SIGNED [4] INT char size=1 bit_offset=0 nr_bits=8 encoding=(none) [5] INT int size=1 bit_offset=0 nr_bits=2 encoding=(none) [6] INT int size=1 bit_offset=0 nr_bits=1 encoding=(none) [7] INT char size=1 bit_offset=0 nr_bits=1 encoding=(none) -bash-4.2$ llc -march=bpfeb -mattr=dwarfris -filetype=obj t.ll -bash-4.2$ pahole -JV t.o [1] PTR (anon) type_id=2 [2] STRUCT t size=16 vlen=7 a type_id=5 bits_offset=0 b type_id=6 bits_offset=2 c type_id=6 bits_offset=6 d type_id=3 bits_offset=32 e type_id=7 bits_offset=64 f type_id=7 bits_offset=65 g type_id=3 bits_offset=96 [3] INT int size=4 bit_offset=0 nr_bits=32 encoding=SIGNED [4] INT char size=1 bit_offset=0 nr_bits=8 encoding=(none) [5] INT int size=1 bit_offset=0 nr_bits=2 encoding=(none) [6] INT int size=1 bit_offset=0 nr_bits=1 encoding=(none) [7] INT char size=1 bit_offset=0 nr_bits=1 encoding=(none) The BTF struct member bits_offset counts bits from the beginning of the containing entity regardless of endianness, similar to what DW_AT_bit_offset from DWARF4 does. Such counting is equivalent to the big endian conversion in the above. But the little endian conversion is not correct since dwarf generates DW_AT_bit_offset based on actual bit position in the little endian architecture. For example, for the above struct member "a", the dwarf would generate DW_AT_bit_offset=30 for little endian, and DW_AT_bit_offset=0 for big endian. This patch fixed the little endian structure member bits_offset problem with proper calculation based on dwarf attributes. With the fix, we get: -bash-4.2$ llc -march=bpfel -mattr=dwarfris -filetype=obj t.ll -bash-4.2$ pahole -JV t.o [1] STRUCT t size=16 vlen=7 a type_id=5 bits_offset=0 b type_id=6 bits_offset=2 c type_id=6 bits_offset=6 d type_id=2 bits_offset=32 e type_id=7 bits_offset=64 f type_id=7 bits_offset=65 g type_id=2 bits_offset=96 [2] INT int size=4 bit_offset=0 nr_bits=32 encoding=SIGNED [3] INT char size=1 bit_offset=0 nr_bits=8 encoding=(none) [4] PTR (anon) type_id=1 [5] INT int size=1 bit_offset=0 nr_bits=2 encoding=(none) [6] INT int size=1 bit_offset=0 nr_bits=1 encoding=(none) [7] INT char size=1 bit_offset=0 nr_bits=1 encoding=(none) -bash-4.2$ llc -march=bpfeb -mattr=dwarfris -filetype=obj t.ll -bash-4.2$ pahole -JV t.o [1] PTR (anon) type_id=2 [2] STRUCT t size=16 vlen=7 a type_id=5 bits_offset=0 b type_id=6 bits_offset=2 c type_id=6 bits_offset=6 d type_id=3 bits_offset=32 e type_id=7 bits_offset=64 f type_id=7 bits_offset=65 g type_id=3 bits_offset=96 [3] INT int size=4 bit_offset=0 nr_bits=32 encoding=SIGNED [4] INT char size=1 bit_offset=0 nr_bits=8 encoding=(none) [5] INT int size=1 bit_offset=0 nr_bits=2 encoding=(none) [6] INT int size=1 bit_offset=0 nr_bits=1 encoding=(none) [7] INT char size=1 bit_offset=0 nr_bits=1 encoding=(none) -bash-4.2$ For both little endian and big endian, we have correct and same bits_offset for struct members. We could fix pos->bit_offset, but pos->bit_offset will be inconsistent to pos->bitfield_offset in the meaning and pos->bitfield_offset is used to print out pahole data structure: -bash-4.2$ llc -march=bpfel -mattr=dwarfris -filetype=obj t.ll -bash-4.2$ /bin/pahole t.o struct t { int a:2; /* 0:30 4 */ int b:1; /* 0:29 4 */ int c:1; /* 0:25 4 */ ..... So this patch just made the change in btf specific routines. Signed-off-by: Yonghong Song <yhs@fb.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Cc: Alexei Starovoitov <ast@fb.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-09-13 18:19:40 +02:00
#include <stdbool.h>
btf: Add BTF support This patch introduces BPF Type Format (BTF). BTF (BPF Type Format) is the meta data format which describes the data types of BPF program/map. Hence, it basically focus on the C programming language which the modern BPF is primary using. The first use case is to provide a generic pretty print capability for a BPF map. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-03-06 01:53:50 +01:00
#include <stdint.h>
Revert "libbpf: allow to use packaged version" This reverts commit 82749180b23d3c9c060108bc290ae26507fc324e. Getting in the way of releasing 1.20, breaking the build of a dwarves rpm when a libbpf package is installed in a fedora 33 system: In file included from /home/acme/rpmbuild/BUILD/dwarves-1.20/strings.c:7: /home/acme/rpmbuild/BUILD/dwarves-1.20/pahole_strings.h:9:10: fatal error: bpf/btf.h: No such file or directory 9 | #include <bpf/btf.h> | ^~~~~~~~~~~ Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2021-02-04 01:43:44 +01:00
#include "lib/bpf/src/btf.h"
btf: Add BTF support This patch introduces BPF Type Format (BTF). BTF (BPF Type Format) is the meta data format which describes the data types of BPF program/map. Hence, it basically focus on the C programming language which the modern BPF is primary using. The first use case is to provide a generic pretty print capability for a BPF map. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-03-06 01:53:50 +01:00
btf: Rename 'struct btf' to 'struct btf_elf' So that we don't clash with libbpf's 'struct btf', in time more internal state now in 'struct btf_elf' will refer to the equivalent internal state in libbpf's 'struct btf', as they have lots in common. Requested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com> Acked-by: Andrii Nakryiko <andrii.nakryiko@gmail.com> Cc: Alexei Starovoitov <ast@fb.com> Cc: Martin Lau <kafai@fb.com> Cc: Yonghong Song <yhs@fb.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-02-14 14:47:32 +01:00
struct btf_elf {
btf: Add BTF support This patch introduces BPF Type Format (BTF). BTF (BPF Type Format) is the meta data format which describes the data types of BPF program/map. Hence, it basically focus on the C programming language which the modern BPF is primary using. The first use case is to provide a generic pretty print capability for a BPF map. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-03-06 01:53:50 +01:00
void *priv;
Elf *elf;
GElf_Ehdr ehdr;
btf_encoder: Teach pahole to store percpu variables in vmlinux BTF. On SMP systems, the global percpu variables are placed in a special '.data..percpu' section, which is stored in a segment whose initial address is set to 0, the addresses of per-CPU variables are relative positive addresses [1]. This patch extracts these variables from vmlinux and places them with their type information in BTF. More specifically, when BTF is encoded, we find the index of the '.data..percpu' section and then traverse the symbol table to find those global objects which are in this section. For each of these objects, we push a BTF_KIND_VAR into the types buffer, and a BTF_VAR_SECINFO into another buffer, percpu_secinfo. When all the CUs have finished processing, we push a BTF_KIND_DATASEC into the btfe->types buffer, followed by the percpu_secinfo's content. In a v5.8-rc3 linux kernel, I was able to extract 288 such variables. The build time overhead is small and the space overhead is also small. See testings below. A found variable can be invalid in two ways: - Its name found in elf_sym__name is invalid. - Its size identified by elf_sym__size is 0. In either case, the BTF containing such symbols will be rejected by the BTF verifier. Normally we should not see such symbols. But if one is seen during BTF encoding, the encoder will exit with error. An new flag '-j' (or '--force') is implemented to help testing, which skips the invalid symbols and force emit a BTF. Testing: - vmlinux size has increased by ~12kb. Before: $ readelf -SW vmlinux | grep BTF [25] .BTF PROGBITS ffffffff821a905c 13a905c 2d2bf8 00 After: $ pahole -J vmlinux $ readelf -SW vmlinux | grep BTF [25] .BTF PROGBITS ffffffff821a905c 13a905c 2d5bca 00 - Common global percpu VARs and DATASEC are found in BTF section. $ bpftool btf dump file vmlinux | grep runqueues [14152] VAR 'runqueues' type_id=13778, linkage=global-alloc $ bpftool btf dump file vmlinux | grep 'cpu_stopper' [17582] STRUCT 'cpu_stopper' size=72 vlen=5 [17601] VAR 'cpu_stopper' type_id=17582, linkage=static $ bpftool btf dump file vmlinux | grep ' DATASEC ' [63652] DATASEC '.data..percpu' size=179288 vlen=288 - Tested bpf selftests. - pahole exits with error if an invalid symbol is seen during encoding, make -f Makefile -j 36 -s PAHOLE: Error: Found symbol of zero size when encoding btf (sym: 'yyy', cu: 'xxx.c'). PAHOLE: Error: Use '-j' or '--force_emit' to ignore such symbols and force emit the btf. scripts/link-vmlinux.sh: line 137: 2475712 Segmentation fault LLVM_OBJCOPY=${OBJCOPY} ${PAHOLE} -J ${1} - With the flag '-j' or '--force', the invalid symbols are ignored. - Further in verbose mode and with '-j' or '--force' set, a warning is generated: PAHOLE: Warning: Found symbol of zero size when encoding btf, ignored (sym: 'yyy', cu: 'xxx.c'). PAHOLE: Warning: Found symbol of invalid name when encoding btf, ignored (sym: 'zzz', cu: 'sss.c'). References: [1] https://lwn.net/Articles/531148/ Signed-off-by: Hao Luo <haoluo@google.com> Tested-by: Andrii Nakryiko <andriin@fb.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com> Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Martin KaFai Lau <kafai@fb.com> Cc: Oleg Rombakh <olegrom@google.com> Cc: dwarves@vger.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-07-08 22:44:10 +02:00
struct elf_symtab *symtab;
struct gobuffer percpu_secinfo;
btf: Add BTF support This patch introduces BPF Type Format (BTF). BTF (BPF Type Format) is the meta data format which describes the data types of BPF program/map. Hence, it basically focus on the C programming language which the modern BPF is primary using. The first use case is to provide a generic pretty print capability for a BPF map. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-03-06 01:53:50 +01:00
char *filename;
int in_fd;
btf_encoder: Teach pahole to store percpu variables in vmlinux BTF. On SMP systems, the global percpu variables are placed in a special '.data..percpu' section, which is stored in a segment whose initial address is set to 0, the addresses of per-CPU variables are relative positive addresses [1]. This patch extracts these variables from vmlinux and places them with their type information in BTF. More specifically, when BTF is encoded, we find the index of the '.data..percpu' section and then traverse the symbol table to find those global objects which are in this section. For each of these objects, we push a BTF_KIND_VAR into the types buffer, and a BTF_VAR_SECINFO into another buffer, percpu_secinfo. When all the CUs have finished processing, we push a BTF_KIND_DATASEC into the btfe->types buffer, followed by the percpu_secinfo's content. In a v5.8-rc3 linux kernel, I was able to extract 288 such variables. The build time overhead is small and the space overhead is also small. See testings below. A found variable can be invalid in two ways: - Its name found in elf_sym__name is invalid. - Its size identified by elf_sym__size is 0. In either case, the BTF containing such symbols will be rejected by the BTF verifier. Normally we should not see such symbols. But if one is seen during BTF encoding, the encoder will exit with error. An new flag '-j' (or '--force') is implemented to help testing, which skips the invalid symbols and force emit a BTF. Testing: - vmlinux size has increased by ~12kb. Before: $ readelf -SW vmlinux | grep BTF [25] .BTF PROGBITS ffffffff821a905c 13a905c 2d2bf8 00 After: $ pahole -J vmlinux $ readelf -SW vmlinux | grep BTF [25] .BTF PROGBITS ffffffff821a905c 13a905c 2d5bca 00 - Common global percpu VARs and DATASEC are found in BTF section. $ bpftool btf dump file vmlinux | grep runqueues [14152] VAR 'runqueues' type_id=13778, linkage=global-alloc $ bpftool btf dump file vmlinux | grep 'cpu_stopper' [17582] STRUCT 'cpu_stopper' size=72 vlen=5 [17601] VAR 'cpu_stopper' type_id=17582, linkage=static $ bpftool btf dump file vmlinux | grep ' DATASEC ' [63652] DATASEC '.data..percpu' size=179288 vlen=288 - Tested bpf selftests. - pahole exits with error if an invalid symbol is seen during encoding, make -f Makefile -j 36 -s PAHOLE: Error: Found symbol of zero size when encoding btf (sym: 'yyy', cu: 'xxx.c'). PAHOLE: Error: Use '-j' or '--force_emit' to ignore such symbols and force emit the btf. scripts/link-vmlinux.sh: line 137: 2475712 Segmentation fault LLVM_OBJCOPY=${OBJCOPY} ${PAHOLE} -J ${1} - With the flag '-j' or '--force', the invalid symbols are ignored. - Further in verbose mode and with '-j' or '--force' set, a warning is generated: PAHOLE: Warning: Found symbol of zero size when encoding btf, ignored (sym: 'yyy', cu: 'xxx.c'). PAHOLE: Warning: Found symbol of invalid name when encoding btf, ignored (sym: 'zzz', cu: 'sss.c'). References: [1] https://lwn.net/Articles/531148/ Signed-off-by: Hao Luo <haoluo@google.com> Tested-by: Andrii Nakryiko <andriin@fb.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com> Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Martin KaFai Lau <kafai@fb.com> Cc: Oleg Rombakh <olegrom@google.com> Cc: dwarves@vger.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-07-08 22:44:10 +02:00
uint32_t percpu_shndx;
uint64_t percpu_base_addr;
btf_encoder: fix BTF variable generation for kernel modules Fix pahole's logic for determining per-CPU variables. For vmlinux, btfe->percpu_base_addr is always 0, so it didn't matter at which point to subtract it to get offset that later was matched against corresponding ELF symbol. For kernel module, though, the situation is different. Kernel module's per-CPU data section has non-zero offset, which is taken into account in all DWARF variable addresses calculation. For such cases, it's important to subtract section offset (btfe->percpu_base_addr) before ELF symbol look up is performed. This patch also records per-CPU data section size and uses it for early filtering of non-per-CPU variables by their address. Fixes: 2e719cca6672 ("btf_encoder: revamp how per-CPU variables are encoded") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Jiri Olsa <jolsa@redhat.com> Cc: kernel-team@fb.com Cc: Hao Luo <haoluo@google.com> Link: https://lore.kernel.org/r/20201211041139.589692-2-andrii@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-12-11 05:11:37 +01:00
uint64_t percpu_sec_sz;
btf_loader: Use libbpf to load BTF Switch BTF loading to completely use libbpf's own struct btf and related APIs. BTF encoding is still happening with pahole's own code, so these two code paths are not sharing anything now. String fetching is happening based on whether btfe->strings were set to non-NULL pointer by btf_encoder. Committer testing: $ cp ~/git/build/bpf-next-v5.9.0-rc8+/vmlinux . $ readelf -SW vmlinux | grep BTF [24] .BTF PROGBITS ffffffff82494ac0 1694ac0 340207 00 A 0 0 1 [25] .BTF_ids PROGBITS ffffffff827d4cc8 19d4cc8 0000a4 00 A 0 0 1 $ ./btfdiff vmlinux $ Signed-off-by: Andrii Nakryiko <andriin@fb.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: bpf@vger.kernel.org Cc: dwarves@vger.kernel.org Cc: kernel-team@fb.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-10-09 01:39:53 +02:00
struct btf *btf;
btf: Add support for split BTF loading and encoding Add support for generating split BTF, in which there is a designated base BTF, containing a base set of types, and a split BTF, which extends main BTF with extra types, that can reference types and strings from the main BTF. This is going to be used to generate compact BTFs for kernel modules, with vmlinux BTF being a main BTF, which all kernel modules are based off of. These changes rely on patch set [0] to be present in libbpf submodule. [0] https://patchwork.kernel.org/project/netdevbpf/list/?series=377859&state=* Committer notes: Fixed up wrt ARGP_numeric_version and added a man page entry. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Cc: bpf@vger.kernel.org Cc: dwarves@vger.kernel.org Cc: kernel-team@fb.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-11-06 06:25:49 +01:00
struct btf *base_btf;
btf: Add BTF support This patch introduces BPF Type Format (BTF). BTF (BPF Type Format) is the meta data format which describes the data types of BPF program/map. Hence, it basically focus on the C programming language which the modern BPF is primary using. The first use case is to provide a generic pretty print capability for a BPF map. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-03-06 01:53:50 +01:00
};
btf: Rename 'struct btf' to 'struct btf_elf' So that we don't clash with libbpf's 'struct btf', in time more internal state now in 'struct btf_elf' will refer to the equivalent internal state in libbpf's 'struct btf', as they have lots in common. Requested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com> Acked-by: Andrii Nakryiko <andrii.nakryiko@gmail.com> Cc: Alexei Starovoitov <ast@fb.com> Cc: Martin Lau <kafai@fb.com> Cc: Yonghong Song <yhs@fb.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-02-14 14:47:32 +01:00
extern uint8_t btf_elf__verbose;
btf_encoder: revamp how per-CPU variables are encoded Right now to encode per-CPU variables in BTF, pahole iterates complete vmlinux symbol table for each CU. There are 2500 CUs for a typical kernel image. Overall, to encode 287 per-CPU variables pahole spends more than 10% of its CPU budget, this is incredibly wasteful. This patch revamps how this is done. Now it pre-processes symbol table once before any of per-CU processing starts. It remembers each per-CPU variable symbol, including its address, size, and name. Then during processing each CU, binary search is used to correlate DWARF variable with per-CPU symbols and figure out if variable belongs to per-CPU data section. If the match is found, BTF_KIND_VAR is emitted and var_secinfo is recorded, just like before. At the very end, after all CUs are processed, BTF_KIND_DATASEC is emitted with sorted variables. This change makes per-CPU variables generation overhead pretty negligible and returns back about 10% of CPU usage. Performance counter stats for './pahole -J /home/andriin/linux-build/default/vmlinux': BEFORE: 19.160149000 seconds user 1.304873000 seconds sys 24,114.05 msec task-clock # 0.999 CPUs utilized 83 context-switches # 0.003 K/sec 0 cpu-migrations # 0.000 K/sec 622,417 page-faults # 0.026 M/sec 72,897,315,125 cycles # 3.023 GHz (25.02%) 127,807,316,959 instructions # 1.75 insn per cycle (25.01%) 29,087,179,117 branches # 1206.234 M/sec (25.01%) 464,105,921 branch-misses # 1.60% of all branches (25.01%) 30,252,119,368 L1-dcache-loads # 1254.543 M/sec (25.01%) 1,156,336,207 L1-dcache-load-misses # 3.82% of all L1-dcache hits (25.05%) 343,373,503 LLC-loads # 14.240 M/sec (25.02%) 12,044,977 LLC-load-misses # 3.51% of all LL-cache hits (25.01%) 24.136198321 seconds time elapsed 22.729693000 seconds user 1.384859000 seconds sys AFTER: 16.781455000 seconds user 1.343956000 seconds sys 23,398.77 msec task-clock # 1.000 CPUs utilized 86 context-switches # 0.004 K/sec 0 cpu-migrations # 0.000 K/sec 622,420 page-faults # 0.027 M/sec 68,395,641,468 cycles # 2.923 GHz (25.05%) 114,241,327,034 instructions # 1.67 insn per cycle (25.01%) 26,330,711,718 branches # 1125.303 M/sec (25.01%) 465,926,869 branch-misses # 1.77% of all branches (25.00%) 24,662,984,772 L1-dcache-loads # 1054.029 M/sec (25.00%) 1,054,052,064 L1-dcache-load-misses # 4.27% of all L1-dcache hits (25.00%) 340,970,622 LLC-loads # 14.572 M/sec (25.00%) 16,032,297 LLC-load-misses # 4.70% of all LL-cache hits (25.03%) 23.402259654 seconds time elapsed 21.916437000 seconds user 1.482826000 seconds sys Committer testing: $ grep 'model name' -m1 /proc/cpuinfo model name : AMD Ryzen 9 3900X 12-Core Processor $ Before: $ perf stat -r5 pahole -J vmlinux Performance counter stats for 'pahole -J vmlinux' (5 runs): 9,730.28 msec task-clock:u # 0.998 CPUs utilized ( +- 0.54% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 353,854 page-faults:u # 0.036 M/sec ( +- 0.00% ) 39,721,726,459 cycles:u # 4.082 GHz ( +- 0.07% ) (83.33%) 626,010,654 stalled-cycles-frontend:u # 1.58% frontend cycles idle ( +- 0.91% ) (83.33%) 7,518,333,691 stalled-cycles-backend:u # 18.93% backend cycles idle ( +- 0.56% ) (83.33%) 85,477,123,093 instructions:u # 2.15 insn per cycle # 0.09 stalled cycles per insn ( +- 0.02% ) (83.34%) 19,346,085,683 branches:u # 1988.235 M/sec ( +- 0.03% ) (83.34%) 237,291,787 branch-misses:u # 1.23% of all branches ( +- 0.15% ) (83.33%) 9.7465 +- 0.0524 seconds time elapsed ( +- 0.54% ) $ After: $ perf stat -r5 pahole -J vmlinux Performance counter stats for 'pahole -J vmlinux' (5 runs): 8,953.80 msec task-clock:u # 0.998 CPUs utilized ( +- 0.09% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 353,855 page-faults:u # 0.040 M/sec ( +- 0.00% ) 35,775,730,539 cycles:u # 3.996 GHz ( +- 0.07% ) (83.33%) 579,534,836 stalled-cycles-frontend:u # 1.62% frontend cycles idle ( +- 2.21% ) (83.33%) 5,719,840,144 stalled-cycles-backend:u # 15.99% backend cycles idle ( +- 0.93% ) (83.33%) 73,035,744,786 instructions:u # 2.04 insn per cycle # 0.08 stalled cycles per insn ( +- 0.02% ) (83.34%) 16,798,017,844 branches:u # 1876.077 M/sec ( +- 0.05% ) (83.33%) 237,777,143 branch-misses:u # 1.42% of all branches ( +- 0.15% ) (83.34%) 8.97077 +- 0.00803 seconds time elapsed ( +- 0.09% ) $ Indeed, about 10% shaved, not bad. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Hao Luo <haoluo@google.com> Cc: Oleg Rombakh <olegrom@google.com> Cc: bpf@vger.kernel.org Cc: dwarves@vger.kernel.org Cc: kernel-team@fb.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-10-09 01:39:57 +02:00
extern uint8_t btf_elf__force;
btf: Rename 'struct btf' to 'struct btf_elf' So that we don't clash with libbpf's 'struct btf', in time more internal state now in 'struct btf_elf' will refer to the equivalent internal state in libbpf's 'struct btf', as they have lots in common. Requested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com> Acked-by: Andrii Nakryiko <andrii.nakryiko@gmail.com> Cc: Alexei Starovoitov <ast@fb.com> Cc: Martin Lau <kafai@fb.com> Cc: Yonghong Song <yhs@fb.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-02-14 14:47:32 +01:00
#define btf_elf__verbose_log(fmt, ...) { if (btf_elf__verbose) printf(fmt, __VA_ARGS__); }
btf: Add support for the floating-point types Some BPF programs compiled on s390 fail to load, because s390 arch-specific linux headers contain float and double types. Fix as follows: - Make the DWARF loader fill base_type.float_type. - Introduce the --btf_gen_floats command-line parameter, so that pahole could be used to build both the older and the newer kernels. - libbpf introduced the support for the floating-point types in commit 986962fade5, so update the libbpf submodule to that version and use the new btf__add_float() function in order to emit the floating-point types when not in the compatibility mode. - Make the BTF loader recognize the new BTF kind. Example of the resulting entry in the vmlinux BTF: [7164] FLOAT 'double' size=8 when building with: LLVM_OBJCOPY=${OBJCOPY} ${PAHOLE} -J ${1} --btf_gen_floats Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Yonghong Song <yhs@fb.com> Cc: bpf@vger.kernel.org Cc: dwarves@vger.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2021-03-10 21:15:50 +01:00
extern bool btf_gen_floats;
btf: Add BTF support This patch introduces BPF Type Format (BTF). BTF (BPF Type Format) is the meta data format which describes the data types of BPF program/map. Hence, it basically focus on the C programming language which the modern BPF is primary using. The first use case is to provide a generic pretty print capability for a BPF map. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-03-06 01:53:50 +01:00
btf_encoder: Teach pahole to store percpu variables in vmlinux BTF. On SMP systems, the global percpu variables are placed in a special '.data..percpu' section, which is stored in a segment whose initial address is set to 0, the addresses of per-CPU variables are relative positive addresses [1]. This patch extracts these variables from vmlinux and places them with their type information in BTF. More specifically, when BTF is encoded, we find the index of the '.data..percpu' section and then traverse the symbol table to find those global objects which are in this section. For each of these objects, we push a BTF_KIND_VAR into the types buffer, and a BTF_VAR_SECINFO into another buffer, percpu_secinfo. When all the CUs have finished processing, we push a BTF_KIND_DATASEC into the btfe->types buffer, followed by the percpu_secinfo's content. In a v5.8-rc3 linux kernel, I was able to extract 288 such variables. The build time overhead is small and the space overhead is also small. See testings below. A found variable can be invalid in two ways: - Its name found in elf_sym__name is invalid. - Its size identified by elf_sym__size is 0. In either case, the BTF containing such symbols will be rejected by the BTF verifier. Normally we should not see such symbols. But if one is seen during BTF encoding, the encoder will exit with error. An new flag '-j' (or '--force') is implemented to help testing, which skips the invalid symbols and force emit a BTF. Testing: - vmlinux size has increased by ~12kb. Before: $ readelf -SW vmlinux | grep BTF [25] .BTF PROGBITS ffffffff821a905c 13a905c 2d2bf8 00 After: $ pahole -J vmlinux $ readelf -SW vmlinux | grep BTF [25] .BTF PROGBITS ffffffff821a905c 13a905c 2d5bca 00 - Common global percpu VARs and DATASEC are found in BTF section. $ bpftool btf dump file vmlinux | grep runqueues [14152] VAR 'runqueues' type_id=13778, linkage=global-alloc $ bpftool btf dump file vmlinux | grep 'cpu_stopper' [17582] STRUCT 'cpu_stopper' size=72 vlen=5 [17601] VAR 'cpu_stopper' type_id=17582, linkage=static $ bpftool btf dump file vmlinux | grep ' DATASEC ' [63652] DATASEC '.data..percpu' size=179288 vlen=288 - Tested bpf selftests. - pahole exits with error if an invalid symbol is seen during encoding, make -f Makefile -j 36 -s PAHOLE: Error: Found symbol of zero size when encoding btf (sym: 'yyy', cu: 'xxx.c'). PAHOLE: Error: Use '-j' or '--force_emit' to ignore such symbols and force emit the btf. scripts/link-vmlinux.sh: line 137: 2475712 Segmentation fault LLVM_OBJCOPY=${OBJCOPY} ${PAHOLE} -J ${1} - With the flag '-j' or '--force', the invalid symbols are ignored. - Further in verbose mode and with '-j' or '--force' set, a warning is generated: PAHOLE: Warning: Found symbol of zero size when encoding btf, ignored (sym: 'yyy', cu: 'xxx.c'). PAHOLE: Warning: Found symbol of invalid name when encoding btf, ignored (sym: 'zzz', cu: 'sss.c'). References: [1] https://lwn.net/Articles/531148/ Signed-off-by: Hao Luo <haoluo@google.com> Tested-by: Andrii Nakryiko <andriin@fb.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com> Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Martin KaFai Lau <kafai@fb.com> Cc: Oleg Rombakh <olegrom@google.com> Cc: dwarves@vger.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-07-08 22:44:10 +02:00
#define PERCPU_SECTION ".data..percpu"
btf_encoder: Use libbpf APIs to encode BTF type info Switch to use libbpf's BTF writing APIs to encode BTF. This reconciles btf_elf's use of internal struct btf from libbpf for both loading and encoding BTF type info. This change also saves a considerable amount of memory used for DWARF to BTF conversion due to avoiding extra memory copy between gobuffers and libbpf's struct btf. Now that pahole uses libbpf's struct btf, it's possible to further utilize libbpf's features and APIs, e.g., for handling endianness conversion, for dumping raw BTF type info during encoding. These features might be implemented in the follow up patches. Committer notes: Built with 'cmake -DCMAKE_BUILD_TYPE=Release' Before: $ cp ~/git/build/bpf-next-v5.9.0-rc8+/vmlinux . $ perf stat -r5 pahole -J vmlinux Performance counter stats for 'pahole -J vmlinux' (5 runs): 10,065.20 msec task-clock:u # 0.998 CPUs utilized ( +- 0.68% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 514,596 page-faults:u # 0.051 M/sec ( +- 0.00% ) 40,098,447,225 cycles:u # 3.984 GHz ( +- 0.26% ) (83.33%) 547,247,149 stalled-cycles-frontend:u # 1.36% frontend cycles idle ( +- 2.00% ) (83.33%) 6,493,462,167 stalled-cycles-backend:u # 16.19% backend cycles idle ( +- 1.53% ) (83.33%) 86,338,929,286 instructions:u # 2.15 insn per cycle # 0.08 stalled cycles per insn ( +- 0.01% ) (83.34%) 19,859,060,127 branches:u # 1973.043 M/sec ( +- 0.02% ) (83.33%) 288,389,742 branch-misses:u # 1.45% of all branches ( +- 0.13% ) (83.33%) 10.0831 +- 0.0683 seconds time elapsed ( +- 0.68% ) $ After: $ perf stat -r5 pahole -J vmlinux Performance counter stats for 'pahole -J vmlinux' (5 runs): 10,043.94 msec task-clock:u # 0.998 CPUs utilized ( +- 0.69% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 412,035 page-faults:u # 0.041 M/sec ( +- 0.00% ) 39,985,610,202 cycles:u # 3.981 GHz ( +- 0.18% ) (83.33%) 657,352,766 stalled-cycles-frontend:u # 1.64% frontend cycles idle ( +- 2.79% ) (83.33%) 7,387,740,861 stalled-cycles-backend:u # 18.48% backend cycles idle ( +- 1.65% ) (83.33%) 85,926,053,845 instructions:u # 2.15 insn per cycle # 0.09 stalled cycles per insn ( +- 0.04% ) (83.34%) 19,428,047,875 branches:u # 1934.305 M/sec ( +- 0.05% ) (83.33%) 240,156,838 branch-misses:u # 1.24% of all branches ( +- 0.14% ) (83.34%) 10.0609 +- 0.0696 seconds time elapsed ( +- 0.69% ) $ $ ./btfdiff vmlinux $ Signed-off-by: Andrii Nakryiko <andriin@fb.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: bpf@vger.kernel.org Cc: dwarves@vger.kernel.org Cc: kernel-team@fb.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-10-09 01:39:54 +02:00
struct cu;
btf: Add BTF support This patch introduces BPF Type Format (BTF). BTF (BPF Type Format) is the meta data format which describes the data types of BPF program/map. Hence, it basically focus on the C programming language which the modern BPF is primary using. The first use case is to provide a generic pretty print capability for a BPF map. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-03-06 01:53:50 +01:00
struct base_type;
btf: add func_proto support Two new btf kinds, BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO, have been added in kernel since https://patchwork.ozlabs.org/cover/1000176/ to support better func introspection. Currently, for a DW_TAG_subroutine_type dwarf type, a simple "void *" is generated instead of real subroutine type. This patch teaches pahole to generate BTF_KIND_FUNC_PROTO properly. After this patch, pahole should have complete type coverage for C frontend with types a bpf program cares. For example, $ cat t1.c typedef int __int32; struct t1 { int a1; int (*f1)(char p1, __int32 p2); } g1; $ cat t2.c typedef int __int32; struct t2 { int a2; int (*f2)(char q1, __int32 q2, ...); int (*f3)(); } g2; int main() { return 0; } $ gcc -O2 -o t1 -g t1.c t2.c $ pahole -JV t1 File t1: [1] TYPEDEF __int32 type_id=2 [2] INT int size=4 bit_offset=0 nr_bits=32 encoding=SIGNED [3] STRUCT t1 kind_flag=0 size=16 vlen=2 a1 type_id=2 bits_offset=0 f1 type_id=6 bits_offset=64 [4] FUNC_PROTO (anon) return=2 args=(5 (anon), 1 (anon)) [5] INT char size=1 bit_offset=0 nr_bits=8 encoding=(none) [6] PTR (anon) type_id=4 [7] TYPEDEF __int32 type_id=8 [8] INT int size=4 bit_offset=0 nr_bits=32 encoding=SIGNED [9] STRUCT t2 kind_flag=0 size=24 vlen=3 a2 type_id=8 bits_offset=0 f2 type_id=12 bits_offset=64 f3 type_id=14 bits_offset=128 [10] FUNC_PROTO (anon) return=8 args=(11 (anon), 7 (anon), vararg) [11] INT char size=1 bit_offset=0 nr_bits=8 encoding=(none) [12] PTR (anon) type_id=10 [13] FUNC_PROTO (anon) return=8 args=(vararg) [14] PTR (anon) type_id=13 $ In the above example, type [4], [10] and [13] represent the func_proto types. BTF_KIND_FUNC, which represents a real subprogram, is not generated in this patch and will be considered later. Signed-off-by: Yonghong Song <yhs@fb.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexei Starovoitov <ast@fb.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-12-18 23:09:42 +01:00
struct ftype;
btf: Add BTF support This patch introduces BPF Type Format (BTF). BTF (BPF Type Format) is the meta data format which describes the data types of BPF program/map. Hence, it basically focus on the C programming language which the modern BPF is primary using. The first use case is to provide a generic pretty print capability for a BPF map. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-03-06 01:53:50 +01:00
btf: Add support for split BTF loading and encoding Add support for generating split BTF, in which there is a designated base BTF, containing a base set of types, and a split BTF, which extends main BTF with extra types, that can reference types and strings from the main BTF. This is going to be used to generate compact BTFs for kernel modules, with vmlinux BTF being a main BTF, which all kernel modules are based off of. These changes rely on patch set [0] to be present in libbpf submodule. [0] https://patchwork.kernel.org/project/netdevbpf/list/?series=377859&state=* Committer notes: Fixed up wrt ARGP_numeric_version and added a man page entry. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Cc: bpf@vger.kernel.org Cc: dwarves@vger.kernel.org Cc: kernel-team@fb.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-11-06 06:25:49 +01:00
struct btf_elf *btf_elf__new(const char *filename, Elf *elf, struct btf *base_btf);
btf_elf: Rename btf_elf__free() to btf_elf__delete() That is the idiom for free its members and then free itself, 'free' is just to free its members. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-02-14 15:03:31 +01:00
void btf_elf__delete(struct btf_elf *btf);
btf: Add BTF support This patch introduces BPF Type Format (BTF). BTF (BPF Type Format) is the meta data format which describes the data types of BPF program/map. Hence, it basically focus on the C programming language which the modern BPF is primary using. The first use case is to provide a generic pretty print capability for a BPF map. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-03-06 01:53:50 +01:00
btf_encoder: Use libbpf APIs to encode BTF type info Switch to use libbpf's BTF writing APIs to encode BTF. This reconciles btf_elf's use of internal struct btf from libbpf for both loading and encoding BTF type info. This change also saves a considerable amount of memory used for DWARF to BTF conversion due to avoiding extra memory copy between gobuffers and libbpf's struct btf. Now that pahole uses libbpf's struct btf, it's possible to further utilize libbpf's features and APIs, e.g., for handling endianness conversion, for dumping raw BTF type info during encoding. These features might be implemented in the follow up patches. Committer notes: Built with 'cmake -DCMAKE_BUILD_TYPE=Release' Before: $ cp ~/git/build/bpf-next-v5.9.0-rc8+/vmlinux . $ perf stat -r5 pahole -J vmlinux Performance counter stats for 'pahole -J vmlinux' (5 runs): 10,065.20 msec task-clock:u # 0.998 CPUs utilized ( +- 0.68% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 514,596 page-faults:u # 0.051 M/sec ( +- 0.00% ) 40,098,447,225 cycles:u # 3.984 GHz ( +- 0.26% ) (83.33%) 547,247,149 stalled-cycles-frontend:u # 1.36% frontend cycles idle ( +- 2.00% ) (83.33%) 6,493,462,167 stalled-cycles-backend:u # 16.19% backend cycles idle ( +- 1.53% ) (83.33%) 86,338,929,286 instructions:u # 2.15 insn per cycle # 0.08 stalled cycles per insn ( +- 0.01% ) (83.34%) 19,859,060,127 branches:u # 1973.043 M/sec ( +- 0.02% ) (83.33%) 288,389,742 branch-misses:u # 1.45% of all branches ( +- 0.13% ) (83.33%) 10.0831 +- 0.0683 seconds time elapsed ( +- 0.68% ) $ After: $ perf stat -r5 pahole -J vmlinux Performance counter stats for 'pahole -J vmlinux' (5 runs): 10,043.94 msec task-clock:u # 0.998 CPUs utilized ( +- 0.69% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 412,035 page-faults:u # 0.041 M/sec ( +- 0.00% ) 39,985,610,202 cycles:u # 3.981 GHz ( +- 0.18% ) (83.33%) 657,352,766 stalled-cycles-frontend:u # 1.64% frontend cycles idle ( +- 2.79% ) (83.33%) 7,387,740,861 stalled-cycles-backend:u # 18.48% backend cycles idle ( +- 1.65% ) (83.33%) 85,926,053,845 instructions:u # 2.15 insn per cycle # 0.09 stalled cycles per insn ( +- 0.04% ) (83.34%) 19,428,047,875 branches:u # 1934.305 M/sec ( +- 0.05% ) (83.33%) 240,156,838 branch-misses:u # 1.24% of all branches ( +- 0.14% ) (83.34%) 10.0609 +- 0.0696 seconds time elapsed ( +- 0.69% ) $ $ ./btfdiff vmlinux $ Signed-off-by: Andrii Nakryiko <andriin@fb.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: bpf@vger.kernel.org Cc: dwarves@vger.kernel.org Cc: kernel-team@fb.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-10-09 01:39:54 +02:00
int32_t btf_elf__add_base_type(struct btf_elf *btf, const struct base_type *bt,
const char *name);
btf: Rename 'struct btf' to 'struct btf_elf' So that we don't clash with libbpf's 'struct btf', in time more internal state now in 'struct btf_elf' will refer to the equivalent internal state in libbpf's 'struct btf', as they have lots in common. Requested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com> Acked-by: Andrii Nakryiko <andrii.nakryiko@gmail.com> Cc: Alexei Starovoitov <ast@fb.com> Cc: Martin Lau <kafai@fb.com> Cc: Yonghong Song <yhs@fb.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-02-14 14:47:32 +01:00
int32_t btf_elf__add_ref_type(struct btf_elf *btf, uint16_t kind, uint32_t type,
btf_encoder: Use libbpf APIs to encode BTF type info Switch to use libbpf's BTF writing APIs to encode BTF. This reconciles btf_elf's use of internal struct btf from libbpf for both loading and encoding BTF type info. This change also saves a considerable amount of memory used for DWARF to BTF conversion due to avoiding extra memory copy between gobuffers and libbpf's struct btf. Now that pahole uses libbpf's struct btf, it's possible to further utilize libbpf's features and APIs, e.g., for handling endianness conversion, for dumping raw BTF type info during encoding. These features might be implemented in the follow up patches. Committer notes: Built with 'cmake -DCMAKE_BUILD_TYPE=Release' Before: $ cp ~/git/build/bpf-next-v5.9.0-rc8+/vmlinux . $ perf stat -r5 pahole -J vmlinux Performance counter stats for 'pahole -J vmlinux' (5 runs): 10,065.20 msec task-clock:u # 0.998 CPUs utilized ( +- 0.68% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 514,596 page-faults:u # 0.051 M/sec ( +- 0.00% ) 40,098,447,225 cycles:u # 3.984 GHz ( +- 0.26% ) (83.33%) 547,247,149 stalled-cycles-frontend:u # 1.36% frontend cycles idle ( +- 2.00% ) (83.33%) 6,493,462,167 stalled-cycles-backend:u # 16.19% backend cycles idle ( +- 1.53% ) (83.33%) 86,338,929,286 instructions:u # 2.15 insn per cycle # 0.08 stalled cycles per insn ( +- 0.01% ) (83.34%) 19,859,060,127 branches:u # 1973.043 M/sec ( +- 0.02% ) (83.33%) 288,389,742 branch-misses:u # 1.45% of all branches ( +- 0.13% ) (83.33%) 10.0831 +- 0.0683 seconds time elapsed ( +- 0.68% ) $ After: $ perf stat -r5 pahole -J vmlinux Performance counter stats for 'pahole -J vmlinux' (5 runs): 10,043.94 msec task-clock:u # 0.998 CPUs utilized ( +- 0.69% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 412,035 page-faults:u # 0.041 M/sec ( +- 0.00% ) 39,985,610,202 cycles:u # 3.981 GHz ( +- 0.18% ) (83.33%) 657,352,766 stalled-cycles-frontend:u # 1.64% frontend cycles idle ( +- 2.79% ) (83.33%) 7,387,740,861 stalled-cycles-backend:u # 18.48% backend cycles idle ( +- 1.65% ) (83.33%) 85,926,053,845 instructions:u # 2.15 insn per cycle # 0.09 stalled cycles per insn ( +- 0.04% ) (83.34%) 19,428,047,875 branches:u # 1934.305 M/sec ( +- 0.05% ) (83.33%) 240,156,838 branch-misses:u # 1.24% of all branches ( +- 0.14% ) (83.34%) 10.0609 +- 0.0696 seconds time elapsed ( +- 0.69% ) $ $ ./btfdiff vmlinux $ Signed-off-by: Andrii Nakryiko <andriin@fb.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: bpf@vger.kernel.org Cc: dwarves@vger.kernel.org Cc: kernel-team@fb.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-10-09 01:39:54 +02:00
const char *name, bool kind_flag);
int btf_elf__add_member(struct btf_elf *btf, const char *name, uint32_t type,
btf: Rename 'struct btf' to 'struct btf_elf' So that we don't clash with libbpf's 'struct btf', in time more internal state now in 'struct btf_elf' will refer to the equivalent internal state in libbpf's 'struct btf', as they have lots in common. Requested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com> Acked-by: Andrii Nakryiko <andrii.nakryiko@gmail.com> Cc: Alexei Starovoitov <ast@fb.com> Cc: Martin Lau <kafai@fb.com> Cc: Yonghong Song <yhs@fb.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-02-14 14:47:32 +01:00
uint32_t bitfield_size, uint32_t bit_offset);
btf_encoder: Use libbpf APIs to encode BTF type info Switch to use libbpf's BTF writing APIs to encode BTF. This reconciles btf_elf's use of internal struct btf from libbpf for both loading and encoding BTF type info. This change also saves a considerable amount of memory used for DWARF to BTF conversion due to avoiding extra memory copy between gobuffers and libbpf's struct btf. Now that pahole uses libbpf's struct btf, it's possible to further utilize libbpf's features and APIs, e.g., for handling endianness conversion, for dumping raw BTF type info during encoding. These features might be implemented in the follow up patches. Committer notes: Built with 'cmake -DCMAKE_BUILD_TYPE=Release' Before: $ cp ~/git/build/bpf-next-v5.9.0-rc8+/vmlinux . $ perf stat -r5 pahole -J vmlinux Performance counter stats for 'pahole -J vmlinux' (5 runs): 10,065.20 msec task-clock:u # 0.998 CPUs utilized ( +- 0.68% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 514,596 page-faults:u # 0.051 M/sec ( +- 0.00% ) 40,098,447,225 cycles:u # 3.984 GHz ( +- 0.26% ) (83.33%) 547,247,149 stalled-cycles-frontend:u # 1.36% frontend cycles idle ( +- 2.00% ) (83.33%) 6,493,462,167 stalled-cycles-backend:u # 16.19% backend cycles idle ( +- 1.53% ) (83.33%) 86,338,929,286 instructions:u # 2.15 insn per cycle # 0.08 stalled cycles per insn ( +- 0.01% ) (83.34%) 19,859,060,127 branches:u # 1973.043 M/sec ( +- 0.02% ) (83.33%) 288,389,742 branch-misses:u # 1.45% of all branches ( +- 0.13% ) (83.33%) 10.0831 +- 0.0683 seconds time elapsed ( +- 0.68% ) $ After: $ perf stat -r5 pahole -J vmlinux Performance counter stats for 'pahole -J vmlinux' (5 runs): 10,043.94 msec task-clock:u # 0.998 CPUs utilized ( +- 0.69% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 412,035 page-faults:u # 0.041 M/sec ( +- 0.00% ) 39,985,610,202 cycles:u # 3.981 GHz ( +- 0.18% ) (83.33%) 657,352,766 stalled-cycles-frontend:u # 1.64% frontend cycles idle ( +- 2.79% ) (83.33%) 7,387,740,861 stalled-cycles-backend:u # 18.48% backend cycles idle ( +- 1.65% ) (83.33%) 85,926,053,845 instructions:u # 2.15 insn per cycle # 0.09 stalled cycles per insn ( +- 0.04% ) (83.34%) 19,428,047,875 branches:u # 1934.305 M/sec ( +- 0.05% ) (83.33%) 240,156,838 branch-misses:u # 1.24% of all branches ( +- 0.14% ) (83.34%) 10.0609 +- 0.0696 seconds time elapsed ( +- 0.69% ) $ $ ./btfdiff vmlinux $ Signed-off-by: Andrii Nakryiko <andriin@fb.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: bpf@vger.kernel.org Cc: dwarves@vger.kernel.org Cc: kernel-team@fb.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-10-09 01:39:54 +02:00
int32_t btf_elf__add_struct(struct btf_elf *btf, uint8_t kind, const char *name, uint32_t size);
btf: Rename 'struct btf' to 'struct btf_elf' So that we don't clash with libbpf's 'struct btf', in time more internal state now in 'struct btf_elf' will refer to the equivalent internal state in libbpf's 'struct btf', as they have lots in common. Requested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com> Acked-by: Andrii Nakryiko <andrii.nakryiko@gmail.com> Cc: Alexei Starovoitov <ast@fb.com> Cc: Martin Lau <kafai@fb.com> Cc: Yonghong Song <yhs@fb.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-02-14 14:47:32 +01:00
int32_t btf_elf__add_array(struct btf_elf *btf, uint32_t type, uint32_t index_type,
uint32_t nelems);
btf_encoder: Use libbpf APIs to encode BTF type info Switch to use libbpf's BTF writing APIs to encode BTF. This reconciles btf_elf's use of internal struct btf from libbpf for both loading and encoding BTF type info. This change also saves a considerable amount of memory used for DWARF to BTF conversion due to avoiding extra memory copy between gobuffers and libbpf's struct btf. Now that pahole uses libbpf's struct btf, it's possible to further utilize libbpf's features and APIs, e.g., for handling endianness conversion, for dumping raw BTF type info during encoding. These features might be implemented in the follow up patches. Committer notes: Built with 'cmake -DCMAKE_BUILD_TYPE=Release' Before: $ cp ~/git/build/bpf-next-v5.9.0-rc8+/vmlinux . $ perf stat -r5 pahole -J vmlinux Performance counter stats for 'pahole -J vmlinux' (5 runs): 10,065.20 msec task-clock:u # 0.998 CPUs utilized ( +- 0.68% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 514,596 page-faults:u # 0.051 M/sec ( +- 0.00% ) 40,098,447,225 cycles:u # 3.984 GHz ( +- 0.26% ) (83.33%) 547,247,149 stalled-cycles-frontend:u # 1.36% frontend cycles idle ( +- 2.00% ) (83.33%) 6,493,462,167 stalled-cycles-backend:u # 16.19% backend cycles idle ( +- 1.53% ) (83.33%) 86,338,929,286 instructions:u # 2.15 insn per cycle # 0.08 stalled cycles per insn ( +- 0.01% ) (83.34%) 19,859,060,127 branches:u # 1973.043 M/sec ( +- 0.02% ) (83.33%) 288,389,742 branch-misses:u # 1.45% of all branches ( +- 0.13% ) (83.33%) 10.0831 +- 0.0683 seconds time elapsed ( +- 0.68% ) $ After: $ perf stat -r5 pahole -J vmlinux Performance counter stats for 'pahole -J vmlinux' (5 runs): 10,043.94 msec task-clock:u # 0.998 CPUs utilized ( +- 0.69% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 412,035 page-faults:u # 0.041 M/sec ( +- 0.00% ) 39,985,610,202 cycles:u # 3.981 GHz ( +- 0.18% ) (83.33%) 657,352,766 stalled-cycles-frontend:u # 1.64% frontend cycles idle ( +- 2.79% ) (83.33%) 7,387,740,861 stalled-cycles-backend:u # 18.48% backend cycles idle ( +- 1.65% ) (83.33%) 85,926,053,845 instructions:u # 2.15 insn per cycle # 0.09 stalled cycles per insn ( +- 0.04% ) (83.34%) 19,428,047,875 branches:u # 1934.305 M/sec ( +- 0.05% ) (83.33%) 240,156,838 branch-misses:u # 1.24% of all branches ( +- 0.14% ) (83.34%) 10.0609 +- 0.0696 seconds time elapsed ( +- 0.69% ) $ $ ./btfdiff vmlinux $ Signed-off-by: Andrii Nakryiko <andriin@fb.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: bpf@vger.kernel.org Cc: dwarves@vger.kernel.org Cc: kernel-team@fb.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-10-09 01:39:54 +02:00
int32_t btf_elf__add_enum(struct btf_elf *btf, const char *name, uint32_t size);
int btf_elf__add_enum_val(struct btf_elf *btf, const char *name, int32_t value);
int32_t btf_elf__add_func_proto(struct btf_elf *btf, struct cu *cu, struct ftype *ftype,
btf: Rename 'struct btf' to 'struct btf_elf' So that we don't clash with libbpf's 'struct btf', in time more internal state now in 'struct btf_elf' will refer to the equivalent internal state in libbpf's 'struct btf', as they have lots in common. Requested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com> Acked-by: Andrii Nakryiko <andrii.nakryiko@gmail.com> Cc: Alexei Starovoitov <ast@fb.com> Cc: Martin Lau <kafai@fb.com> Cc: Yonghong Song <yhs@fb.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-02-14 14:47:32 +01:00
uint32_t type_id_off);
btf_encoder: Use libbpf APIs to encode BTF type info Switch to use libbpf's BTF writing APIs to encode BTF. This reconciles btf_elf's use of internal struct btf from libbpf for both loading and encoding BTF type info. This change also saves a considerable amount of memory used for DWARF to BTF conversion due to avoiding extra memory copy between gobuffers and libbpf's struct btf. Now that pahole uses libbpf's struct btf, it's possible to further utilize libbpf's features and APIs, e.g., for handling endianness conversion, for dumping raw BTF type info during encoding. These features might be implemented in the follow up patches. Committer notes: Built with 'cmake -DCMAKE_BUILD_TYPE=Release' Before: $ cp ~/git/build/bpf-next-v5.9.0-rc8+/vmlinux . $ perf stat -r5 pahole -J vmlinux Performance counter stats for 'pahole -J vmlinux' (5 runs): 10,065.20 msec task-clock:u # 0.998 CPUs utilized ( +- 0.68% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 514,596 page-faults:u # 0.051 M/sec ( +- 0.00% ) 40,098,447,225 cycles:u # 3.984 GHz ( +- 0.26% ) (83.33%) 547,247,149 stalled-cycles-frontend:u # 1.36% frontend cycles idle ( +- 2.00% ) (83.33%) 6,493,462,167 stalled-cycles-backend:u # 16.19% backend cycles idle ( +- 1.53% ) (83.33%) 86,338,929,286 instructions:u # 2.15 insn per cycle # 0.08 stalled cycles per insn ( +- 0.01% ) (83.34%) 19,859,060,127 branches:u # 1973.043 M/sec ( +- 0.02% ) (83.33%) 288,389,742 branch-misses:u # 1.45% of all branches ( +- 0.13% ) (83.33%) 10.0831 +- 0.0683 seconds time elapsed ( +- 0.68% ) $ After: $ perf stat -r5 pahole -J vmlinux Performance counter stats for 'pahole -J vmlinux' (5 runs): 10,043.94 msec task-clock:u # 0.998 CPUs utilized ( +- 0.69% ) 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 412,035 page-faults:u # 0.041 M/sec ( +- 0.00% ) 39,985,610,202 cycles:u # 3.981 GHz ( +- 0.18% ) (83.33%) 657,352,766 stalled-cycles-frontend:u # 1.64% frontend cycles idle ( +- 2.79% ) (83.33%) 7,387,740,861 stalled-cycles-backend:u # 18.48% backend cycles idle ( +- 1.65% ) (83.33%) 85,926,053,845 instructions:u # 2.15 insn per cycle # 0.09 stalled cycles per insn ( +- 0.04% ) (83.34%) 19,428,047,875 branches:u # 1934.305 M/sec ( +- 0.05% ) (83.33%) 240,156,838 branch-misses:u # 1.24% of all branches ( +- 0.14% ) (83.34%) 10.0609 +- 0.0696 seconds time elapsed ( +- 0.69% ) $ $ ./btfdiff vmlinux $ Signed-off-by: Andrii Nakryiko <andriin@fb.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: bpf@vger.kernel.org Cc: dwarves@vger.kernel.org Cc: kernel-team@fb.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-10-09 01:39:54 +02:00
int32_t btf_elf__add_var_type(struct btf_elf *btfe, uint32_t type, const char *name,
btf_encoder: Teach pahole to store percpu variables in vmlinux BTF. On SMP systems, the global percpu variables are placed in a special '.data..percpu' section, which is stored in a segment whose initial address is set to 0, the addresses of per-CPU variables are relative positive addresses [1]. This patch extracts these variables from vmlinux and places them with their type information in BTF. More specifically, when BTF is encoded, we find the index of the '.data..percpu' section and then traverse the symbol table to find those global objects which are in this section. For each of these objects, we push a BTF_KIND_VAR into the types buffer, and a BTF_VAR_SECINFO into another buffer, percpu_secinfo. When all the CUs have finished processing, we push a BTF_KIND_DATASEC into the btfe->types buffer, followed by the percpu_secinfo's content. In a v5.8-rc3 linux kernel, I was able to extract 288 such variables. The build time overhead is small and the space overhead is also small. See testings below. A found variable can be invalid in two ways: - Its name found in elf_sym__name is invalid. - Its size identified by elf_sym__size is 0. In either case, the BTF containing such symbols will be rejected by the BTF verifier. Normally we should not see such symbols. But if one is seen during BTF encoding, the encoder will exit with error. An new flag '-j' (or '--force') is implemented to help testing, which skips the invalid symbols and force emit a BTF. Testing: - vmlinux size has increased by ~12kb. Before: $ readelf -SW vmlinux | grep BTF [25] .BTF PROGBITS ffffffff821a905c 13a905c 2d2bf8 00 After: $ pahole -J vmlinux $ readelf -SW vmlinux | grep BTF [25] .BTF PROGBITS ffffffff821a905c 13a905c 2d5bca 00 - Common global percpu VARs and DATASEC are found in BTF section. $ bpftool btf dump file vmlinux | grep runqueues [14152] VAR 'runqueues' type_id=13778, linkage=global-alloc $ bpftool btf dump file vmlinux | grep 'cpu_stopper' [17582] STRUCT 'cpu_stopper' size=72 vlen=5 [17601] VAR 'cpu_stopper' type_id=17582, linkage=static $ bpftool btf dump file vmlinux | grep ' DATASEC ' [63652] DATASEC '.data..percpu' size=179288 vlen=288 - Tested bpf selftests. - pahole exits with error if an invalid symbol is seen during encoding, make -f Makefile -j 36 -s PAHOLE: Error: Found symbol of zero size when encoding btf (sym: 'yyy', cu: 'xxx.c'). PAHOLE: Error: Use '-j' or '--force_emit' to ignore such symbols and force emit the btf. scripts/link-vmlinux.sh: line 137: 2475712 Segmentation fault LLVM_OBJCOPY=${OBJCOPY} ${PAHOLE} -J ${1} - With the flag '-j' or '--force', the invalid symbols are ignored. - Further in verbose mode and with '-j' or '--force' set, a warning is generated: PAHOLE: Warning: Found symbol of zero size when encoding btf, ignored (sym: 'yyy', cu: 'xxx.c'). PAHOLE: Warning: Found symbol of invalid name when encoding btf, ignored (sym: 'zzz', cu: 'sss.c'). References: [1] https://lwn.net/Articles/531148/ Signed-off-by: Hao Luo <haoluo@google.com> Tested-by: Andrii Nakryiko <andriin@fb.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com> Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Martin KaFai Lau <kafai@fb.com> Cc: Oleg Rombakh <olegrom@google.com> Cc: dwarves@vger.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-07-08 22:44:10 +02:00
uint32_t linkage);
int32_t btf_elf__add_var_secinfo(struct gobuffer *buf, uint32_t type,
uint32_t offset, uint32_t size);
int32_t btf_elf__add_datasec_type(struct btf_elf *btfe, const char *section_name,
struct gobuffer *var_secinfo_buf);
btf: Rename 'struct btf' to 'struct btf_elf' So that we don't clash with libbpf's 'struct btf', in time more internal state now in 'struct btf_elf' will refer to the equivalent internal state in libbpf's 'struct btf', as they have lots in common. Requested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com> Acked-by: Andrii Nakryiko <andrii.nakryiko@gmail.com> Cc: Alexei Starovoitov <ast@fb.com> Cc: Martin Lau <kafai@fb.com> Cc: Yonghong Song <yhs@fb.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-02-14 14:47:32 +01:00
int btf_elf__encode(struct btf_elf *btf, uint8_t flags);
btf: Add BTF support This patch introduces BPF Type Format (BTF). BTF (BPF Type Format) is the meta data format which describes the data types of BPF program/map. Hence, it basically focus on the C programming language which the modern BPF is primary using. The first use case is to provide a generic pretty print capability for a BPF map. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-03-06 01:53:50 +01:00
btf_loader: Use libbpf to load BTF Switch BTF loading to completely use libbpf's own struct btf and related APIs. BTF encoding is still happening with pahole's own code, so these two code paths are not sharing anything now. String fetching is happening based on whether btfe->strings were set to non-NULL pointer by btf_encoder. Committer testing: $ cp ~/git/build/bpf-next-v5.9.0-rc8+/vmlinux . $ readelf -SW vmlinux | grep BTF [24] .BTF PROGBITS ffffffff82494ac0 1694ac0 340207 00 A 0 0 1 [25] .BTF_ids PROGBITS ffffffff827d4cc8 19d4cc8 0000a4 00 A 0 0 1 $ ./btfdiff vmlinux $ Signed-off-by: Andrii Nakryiko <andriin@fb.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: bpf@vger.kernel.org Cc: dwarves@vger.kernel.org Cc: kernel-team@fb.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-10-09 01:39:53 +02:00
const char *btf_elf__string(struct btf_elf *btf, uint32_t ref);
btf: Rename 'struct btf' to 'struct btf_elf' So that we don't clash with libbpf's 'struct btf', in time more internal state now in 'struct btf_elf' will refer to the equivalent internal state in libbpf's 'struct btf', as they have lots in common. Requested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com> Acked-by: Andrii Nakryiko <andrii.nakryiko@gmail.com> Cc: Alexei Starovoitov <ast@fb.com> Cc: Martin Lau <kafai@fb.com> Cc: Yonghong Song <yhs@fb.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-02-14 14:47:32 +01:00
int btf_elf__load(struct btf_elf *btf);
btf_loader: Introduce a loader for the BTF format Show 'struct list_head' from DWARF info: $ pahole -C list_head ~/git/build/v4.20-rc5+/net/ipv4/tcp.o struct list_head { struct list_head * next; /* 0 8 */ struct list_head * prev; /* 8 8 */ /* size: 16, cachelines: 1, members: 2 */ /* last cacheline: 16 bytes */ }; Try to show it from BTF, on a file without it: $ pahole -F btf -C list_head ~/git/build/v4.20-rc5+/net/ipv4/tcp.o pahole: /home/acme/git/build/v4.20-rc5+/net/ipv4/tcp.o: No debugging information found Encode BTF from the DWARF info: $ pahole -J ~/git/build/v4.20-rc5+/net/ipv4/tcp.o Check that it is there: $ readelf -SW ~/git/build/v4.20-rc5+/net/ipv4/tcp.o | grep BTF readelf: /home/acme/git/build/v4.20-rc5+/net/ipv4/tcp.o: Warning: possibly corrupt ELF header - it has a non-zero program header offset, but no program headers [136] .BTF PROGBITS 0000000000000000 101d0e 042edf 00 0 0 1 Now try again printing 'struct list_head' from the BTF info just encoded: $ pahole -F btf -C list_head ~/git/build/v4.20-rc5+/net/ipv4/tcp.o 2> /dev/null struct list_head { struct list_head * next; /* 0 8 */ struct list_head * prev; /* 8 8 */ /* size: 16, cachelines: 1, members: 2 */ /* last cacheline: 16 bytes */ }; $ There is the bitfields case that BTF desn't have the bit_size info for bitfield members that makes the output from dwarf to be different than the one from BTF: $ pahole -F btf -C sk_buff ~/git/build/v4.20-rc5+/net/ipv4/tcp.o > /tmp/sk_buff.btf $ pahole -F dwarf -C sk_buff ~/git/build/v4.20-rc5+/net/ipv4/tcp.o > /tmp/sk_buff.dwarf $ diff -u /tmp/sk_buff.dwarf /tmp/sk_buff.btf --- /tmp/sk_buff.dwarf 2018-12-20 14:50:51.428653046 -0300 +++ /tmp/sk_buff.btf 2018-12-20 14:50:46.302601516 -0300 @@ -38,45 +38,45 @@ __u16 hdr_len; /* 138 2 */ __u16 queue_mapping; /* 140 2 */ __u8 __cloned_offset[0]; /* 142 0 */ - __u8 cloned:1; /* 142: 7 1 */ - __u8 nohdr:1; /* 142: 6 1 */ - __u8 fclone:2; /* 142: 4 1 */ - __u8 peeked:1; /* 142: 3 1 */ - __u8 head_frag:1; /* 142: 2 1 */ - __u8 xmit_more:1; /* 142: 1 1 */ - __u8 pfmemalloc:1; /* 142: 0 1 */ + __u8 cloned; /* 142 1 */ + __u8 nohdr; /* 142 1 */ + __u8 fclone; /* 142 1 */ + __u8 peeked; /* 142 1 */ + __u8 head_frag; /* 142 1 */ + __u8 xmit_more; /* 142 1 */ + __u8 pfmemalloc; /* 142 1 */ /* XXX 1 byte hole, try to pack */ __u32 headers_start[0]; /* 144 0 */ __u8 __pkt_type_offset[0]; /* 144 0 */ - __u8 pkt_type:3; /* 144: 5 1 */ - __u8 ignore_df:1; /* 144: 4 1 */ - __u8 nf_trace:1; /* 144: 3 1 */ - __u8 ip_summed:2; /* 144: 1 1 */ - __u8 ooo_okay:1; /* 144: 0 1 */ - __u8 l4_hash:1; /* 145: 7 1 */ - __u8 sw_hash:1; /* 145: 6 1 */ - __u8 wifi_acked_valid:1; /* 145: 5 1 */ - __u8 wifi_acked:1; /* 145: 4 1 */ - __u8 no_fcs:1; /* 145: 3 1 */ - __u8 encapsulation:1; /* 145: 2 1 */ - __u8 encap_hdr_csum:1; /* 145: 1 1 */ - __u8 csum_valid:1; /* 145: 0 1 */ - __u8 csum_complete_sw:1; /* 146: 7 1 */ - __u8 csum_level:2; /* 146: 5 1 */ - __u8 csum_not_inet:1; /* 146: 4 1 */ - __u8 dst_pending_confirm:1; /* 146: 3 1 */ - __u8 ndisc_nodetype:2; /* 146: 1 1 */ - __u8 ipvs_property:1; /* 146: 0 1 */ - __u8 inner_protocol_type:1; /* 147: 7 1 */ - __u8 remcsum_offload:1; /* 147: 6 1 */ - __u8 offload_fwd_mark:1; /* 147: 5 1 */ - __u8 offload_mr_fwd_mark:1; /* 147: 4 1 */ - __u8 tc_skip_classify:1; /* 147: 3 1 */ - __u8 tc_at_ingress:1; /* 147: 2 1 */ - __u8 tc_redirected:1; /* 147: 1 1 */ - __u8 tc_from_ingress:1; /* 147: 0 1 */ + __u8 pkt_type; /* 144 1 */ + __u8 ignore_df; /* 144 1 */ + __u8 nf_trace; /* 144 1 */ + __u8 ip_summed; /* 144 1 */ + __u8 ooo_okay; /* 144 1 */ + __u8 l4_hash; /* 145 1 */ + __u8 sw_hash; /* 145 1 */ + __u8 wifi_acked_valid; /* 145 1 */ + __u8 wifi_acked; /* 145 1 */ + __u8 no_fcs; /* 145 1 */ + __u8 encapsulation; /* 145 1 */ + __u8 encap_hdr_csum; /* 145 1 */ + __u8 csum_valid; /* 145 1 */ + __u8 csum_complete_sw; /* 146 1 */ + __u8 csum_level; /* 146 1 */ + __u8 csum_not_inet; /* 146 1 */ + __u8 dst_pending_confirm; /* 146 1 */ + __u8 ndisc_nodetype; /* 146 1 */ + __u8 ipvs_property; /* 146 1 */ + __u8 inner_protocol_type; /* 147 1 */ + __u8 remcsum_offload; /* 147 1 */ + __u8 offload_fwd_mark; /* 147 1 */ + __u8 offload_mr_fwd_mark; /* 147 1 */ + __u8 tc_skip_classify; /* 147 1 */ + __u8 tc_at_ingress; /* 147 1 */ + __u8 tc_redirected; /* 147 1 */ + __u8 tc_from_ingress; /* 147 1 */ __u16 tc_index; /* 148 2 */ /* XXX 2 bytes hole, try to pack */ $ Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-12-03 19:44:16 +01:00
btf: Add BTF support This patch introduces BPF Type Format (BTF). BTF (BPF Type Format) is the meta data format which describes the data types of BPF program/map. Hence, it basically focus on the C programming language which the modern BPF is primary using. The first use case is to provide a generic pretty print capability for a BPF map. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-03-06 01:53:50 +01:00
#endif /* _LIBBTF_H */
Reference in New Issue Copy Permalink