From: Giuliano Procida <gprocida@google.com>
To: dwarves@vger.kernel.org
Cc: acme@kernel.org, andrii@kernel.org, ast@kernel.org,
gprocida@google.com, maennich@google.com,
kernel-team@android.com, kernel-team@fb.com, bpf@vger.kernel.org
Subject: [PATCH dwarves v2 0/4] BTF ELF writing changes
Date: Mon, 1 Feb 2021 17:25:26 +0000 [thread overview]
Message-ID: <20210201172530.1141087-1-gprocida@google.com> (raw)
In-Reply-To: <87a83353155506cc02141e6e4108d89aa4e7d284>
Note: The 4 patches in this series supersede patches 2-4 of the
previous version of this series (patch 1 was applied).
pahole -J currently uses llvm-objcopy to add .BTF as a section (and
segment) to an ELF object containing DWARF debug information. If a
.BTF section is already present it is rewritten but segment
information is not updated.
In terms of the current Linux linker script, all that's needed is
either a dump of the raw BTF or a file containing a .BTF section. This
is because the script dumps .BTF out to a file, creates a
single-section ELF file and then links this into a final vmlinux.
The first commit in this series removes the dependency on
llvm-objcopy.
The remaining commits attempt to roughly duplicate the desired end
result, namely adding a .BTF section which is also a loadable segment.
They may not be sufficient. In terms of non-kernel .BTF use, they are
probably not necessary.
Nevertheless, this was an interesting exercise and removing the
llvm-objcopy dependency is a worthwhile goal.
I'm not well-placed to test the viability of vmlinux with .BTF as
generated by these patches, so any feedback is very welcome.
Giuliano Procida (4):
btf_encoder: Add .BTF section using libelf
btf_encoder: Manually lay out updated ELF sections
btf_encoder: Add .BTF as a loadable segment
btf_encoder: Align .BTF section/segment to 8 bytes
libbtf.c | 240 +++++++++++++++++++++++++++++++++++++++++++++----------
1 file changed, 197 insertions(+), 43 deletions(-)
--
2.30.0.365.g02bc693789-goog
next parent reply other threads:[~2021-02-01 17:26 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <87a83353155506cc02141e6e4108d89aa4e7d284>
2021-02-01 17:25 ` Giuliano Procida [this message]
2021-02-01 17:25 ` [PATCH dwarves v2 1/4] btf_encoder: Add .BTF section using libelf Giuliano Procida
2021-02-04 4:10 ` Andrii Nakryiko
2021-02-04 18:29 ` Giuliano Procida
2021-02-01 17:25 ` [PATCH dwarves v2 2/4] btf_encoder: Manually lay out updated ELF sections Giuliano Procida
2021-02-04 4:13 ` Andrii Nakryiko
2021-02-04 18:34 ` Giuliano Procida
2021-02-04 23:06 ` Andrii Nakryiko
2021-02-01 17:25 ` [PATCH dwarves v2 3/4] btf_encoder: Add .BTF as a loadable segment Giuliano Procida
2021-02-02 10:54 ` Giuliano Procida
2021-02-01 17:25 ` [PATCH dwarves v2 4/4] btf_encoder: Align .BTF section/segment to 8 bytes Giuliano Procida
2021-02-04 4:10 ` Andrii Nakryiko
2021-02-04 15:11 ` Giuliano Procida
2021-02-04 15:11 ` [PATCH] btf_encoder: Align .BTF section " Giuliano Procida
2021-02-05 13:42 ` [PATCH dwarves v3 0/5] ELF writing changes Giuliano Procida
2021-02-05 13:42 ` [PATCH dwarves v3 1/5] btf_encoder: Funnel ELF error reporting through a macro Giuliano Procida
2021-02-08 22:20 ` Andrii Nakryiko
2021-02-05 13:42 ` [PATCH dwarves v3 2/5] btf_encoder: Do not use both structs and pointers for the same data Giuliano Procida
2021-02-08 22:23 ` Andrii Nakryiko
2021-02-09 14:52 ` Giuliano Procida
2021-02-05 13:42 ` [PATCH dwarves v3 3/5] btf_encoder: Traverse sections using a for-loop Giuliano Procida
2021-02-08 22:24 ` Andrii Nakryiko
2021-02-09 14:59 ` Giuliano Procida
2021-02-05 13:42 ` [PATCH dwarves v3 4/5] btf_encoder: Add .BTF section using libelf Giuliano Procida
2021-02-08 22:29 ` Andrii Nakryiko
2021-02-09 15:04 ` Giuliano Procida
2021-02-05 13:42 ` [PATCH dwarves v3 5/5] btf_encoder: Align .BTF section to 8 bytes Giuliano Procida
2021-02-08 22:29 ` Andrii Nakryiko
2021-02-09 15:05 ` Giuliano Procida
2021-02-17 11:07 ` [PATCH dwarves v4 0/5] ELF writing changes Giuliano Procida
2021-02-17 11:08 ` [PATCH dwarves v4 1/5] btf_encoder: Funnel ELF error reporting through a macro Giuliano Procida
2021-02-17 11:08 ` [PATCH dwarves v4 2/5] btf_encoder: Do not use both structs and pointers for the same data Giuliano Procida
2021-02-17 11:08 ` [PATCH dwarves v4 3/5] btf_encoder: Traverse sections using a for-loop Giuliano Procida
2021-02-17 11:08 ` [PATCH dwarves v4 4/5] btf_encoder: Add .BTF section using libelf Giuliano Procida
2021-02-17 11:08 ` [PATCH dwarves v4 5/5] btf_encoder: Align .BTF section to 8 bytes Giuliano Procida
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