linux-stable.git/tools/lib/bpf/Makefile, branch linux-5.15.y

libbpf: Fix build issue with llvm-readelf

2022-04-13T18:59:03+00:00

[ Upstream commit 0908a66ad1124c1634c33847ac662106f7f2c198 ]

There are cases where clang compiler is packaged in a way
readelf is a symbolic link to llvm-readelf. In such cases,
llvm-readelf will be used instead of default binutils readelf,
and the following error will appear during libbpf build:

#  Warning: Num of global symbols in
#   /home/yhs/work/bpf-next/tools/testing/selftests/bpf/tools/build/libbpf/sharedobjs/libbpf-in.o (367)
#   does NOT match with num of versioned symbols in
#   /home/yhs/work/bpf-next/tools/testing/selftests/bpf/tools/build/libbpf/libbpf.so libbpf.map (383).
#   Please make sure all LIBBPF_API symbols are versioned in libbpf.map.
#  --- /home/yhs/work/bpf-next/tools/testing/selftests/bpf/tools/build/libbpf/libbpf_global_syms.tmp ...
#  +++ /home/yhs/work/bpf-next/tools/testing/selftests/bpf/tools/build/libbpf/libbpf_versioned_syms.tmp ...
#  @@ -324,6 +324,22 @@
#   btf__str_by_offset
#   btf__type_by_id
#   btf__type_cnt
#  +LIBBPF_0.0.1
#  +LIBBPF_0.0.2
#  +LIBBPF_0.0.3
#  +LIBBPF_0.0.4
#  +LIBBPF_0.0.5
#  +LIBBPF_0.0.6
#  +LIBBPF_0.0.7
#  +LIBBPF_0.0.8
#  +LIBBPF_0.0.9
#  +LIBBPF_0.1.0
#  +LIBBPF_0.2.0
#  +LIBBPF_0.3.0
#  +LIBBPF_0.4.0
#  +LIBBPF_0.5.0
#  +LIBBPF_0.6.0
#  +LIBBPF_0.7.0
#   libbpf_attach_type_by_name
#   libbpf_find_kernel_btf
#   libbpf_find_vmlinux_btf_id
#  make[2]: *** [Makefile:184: check_abi] Error 1
#  make[1]: *** [Makefile:140: all] Error 2

The above failure is due to different printouts for some ABS
versioned symbols. For example, with the same libbpf.so,
  $ /bin/readelf --dyn-syms --wide tools/lib/bpf/libbpf.so | grep "LIBBPF" | grep ABS
     134: 0000000000000000     0 OBJECT  GLOBAL DEFAULT  ABS LIBBPF_0.5.0
     202: 0000000000000000     0 OBJECT  GLOBAL DEFAULT  ABS LIBBPF_0.6.0
     ...
  $ /opt/llvm/bin/readelf --dyn-syms --wide tools/lib/bpf/libbpf.so | grep "LIBBPF" | grep ABS
     134: 0000000000000000     0 OBJECT  GLOBAL DEFAULT   ABS LIBBPF_0.5.0@@LIBBPF_0.5.0
     202: 0000000000000000     0 OBJECT  GLOBAL DEFAULT   ABS LIBBPF_0.6.0@@LIBBPF_0.6.0
     ...
The binutils readelf doesn't print out the symbol LIBBPF_* version and llvm-readelf does.
Such a difference caused libbpf build failure with llvm-readelf.

The proposed fix filters out all ABS symbols as they are not part of the comparison.
This works for both binutils readelf and llvm-readelf.

Reported-by: Delyan Kratunov 
Signed-off-by: Yonghong Song 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20220204214355.502108-1-yhs@fb.com
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

libbpf: Re-build libbpf.so when libbpf.map changes

2021-08-16T22:45:07+00:00

Ensure libbpf.so is re-built whenever libbpf.map is modified.  Without this,
changes to libbpf.map are not detected and versioned symbols mismatch error
will be reported until `make clean && make` is used, which is a suboptimal
developer experience.

Fixes: 306b267cb3c4 ("libbpf: Verify versioned symbols")
Signed-off-by: Andrii Nakryiko 
Signed-off-by: Daniel Borkmann 
Acked-by: Yonghong Song 
Link: https://lore.kernel.org/bpf/20210815070609.987780-8-andrii@kernel.org

libbpf: Install skel_internal.h header used from light skeletons

2021-06-03T13:50:11+00:00

Light skeleton code assumes skel_internal.h header to be installed system-wide
by libbpf package. Make sure it is actually installed.

Fixes: 67234743736a ("libbpf: Generate loader program out of BPF ELF file.")
Signed-off-by: Andrii Nakryiko 
Signed-off-by: Daniel Borkmann 
Link: https://lore.kernel.org/bpf/20210603004026.2698513-4-andrii@kernel.org

libbpf: Refactor header installation portions of Makefile

2021-06-03T13:50:11+00:00

As we gradually get more headers that have to be installed, it's quite
annoying to copy/paste long $(call) commands. So extract that logic and do
a simple $(foreach) over the list of headers.

Signed-off-by: Andrii Nakryiko 
Signed-off-by: Daniel Borkmann 
Link: https://lore.kernel.org/bpf/20210603004026.2698513-3-andrii@kernel.org

libbpf: Add libbpf_set_strict_mode() API to turn on libbpf 1.0 behaviors

2021-05-26T00:32:34+00:00

Add libbpf_set_strict_mode() API that allows application to simulate libbpf
1.0 breaking changes before libbpf 1.0 is released. This will help users
migrate gradually and with confidence.

For now only ALL or NONE options are available, subsequent patches will add
more flags. This patch is preliminary for selftests/bpf changes.

Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Acked-by: John Fastabend 
Acked-by: Toke Høiland-Jørgensen 
Link: https://lore.kernel.org/bpf/20210525035935.1461796-2-andrii@kernel.org

Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

2021-03-25T23:30:46+00:00

Alexei Starovoitov says:

====================
pull-request: bpf-next 2021-03-24

The following pull-request contains BPF updates for your *net-next* tree.

We've added 37 non-merge commits during the last 15 day(s) which contain
a total of 65 files changed, 3200 insertions(+), 738 deletions(-).

The main changes are:

1) Static linking of multiple BPF ELF files, from Andrii.

2) Move drop error path to devmap for XDP_REDIRECT, from Lorenzo.

3) Spelling fixes from various folks.
====================

Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2021-03-25T22:31:22+00:00

Signed-off-by: David S. Miller

libbpf: xsk: Move barriers from libbpf_util.h to xsk.h

2021-03-10T21:45:16+00:00

The only user of libbpf_util.h is xsk.h. Move the barriers to xsk.h,
and remove libbpf_util.h. The barriers are used as an implementation
detail, and should not be considered part of the stable API.

Signed-off-by: Björn Töpel 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20210310080929.641212-3-bjorn.topel@gmail.com

libbpf: Fix INSTALL flag order

2021-03-08T18:43:27+00:00

It was reported ([0]) that having optional -m flag between source and
destination arguments in install command breaks bpftools cross-build
on MacOS. Move -m to the front to fix this issue.

  [0] https://github.com/openwrt/openwrt/pull/3959

Fixes: 7110d80d53f4 ("libbpf: Makefile set specified permission mode")
Signed-off-by: Georgi Valkov 
Signed-off-by: Andrii Nakryiko 
Signed-off-by: Daniel Borkmann 
Link: https://lore.kernel.org/bpf/20210308183038.613432-1-andrii@kernel.org

scripts/bpf: Abstract eBPF API target parameter

2021-03-05T02:39:45+00:00

Abstract out the target parameter so that upcoming commits, more than
just the existing "helpers" target can be called to generate specific
portions of docs from the eBPF UAPI headers.

Signed-off-by: Joe Stringer 
Signed-off-by: Alexei Starovoitov 
Reviewed-by: Quentin Monnet 
Acked-by: Toke Høiland-Jørgensen 
Link: https://lore.kernel.org/bpf/20210302171947.2268128-10-joe@cilium.io