linux/tools
Andrii Nakryiko ba451366bf libbpf: Implement basic split BTF support
Support split BTF operation, in which one BTF (base BTF) provides basic set of
types and strings, while another one (split BTF) builds on top of base's types
and strings and adds its own new types and strings. From API standpoint, the
fact that the split BTF is built on top of the base BTF is transparent.

Type numeration is transparent. If the base BTF had last type ID #N, then all
types in the split BTF start at type ID N+1. Any type in split BTF can
reference base BTF types, but not vice versa. Programmatically construction of
a split BTF on top of a base BTF is supported: one can create an empty split
BTF with btf__new_empty_split() and pass base BTF as an input, or pass raw
binary data to btf__new_split(), or use btf__parse_xxx_split() variants to get
initial set of split types/strings from the ELF file with .BTF section.

String offsets are similarly transparent and are a logical continuation of
base BTF's strings. When building BTF programmatically and adding a new string
(explicitly with btf__add_str() or implicitly through appending new
types/members), string-to-be-added would first be looked up from the base
BTF's string section and re-used if it's there. If not, it will be looked up
and/or added to the split BTF string section. Similarly to type IDs, types in
split BTF can refer to strings from base BTF absolutely transparently (but not
vice versa, of course, because base BTF doesn't "know" about existence of
split BTF).

Internal type index is slightly adjusted to be zero-indexed, ignoring a fake
[0] VOID type. This allows to handle split/base BTF type lookups transparently
by using btf->start_id type ID offset, which is always 1 for base/non-split
BTF and equals btf__get_nr_types(base_btf) + 1 for the split BTF.

BTF deduplication is not yet supported for split BTF and support for it will
be added in separate patch.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20201105043402.2530976-5-andrii@kernel.org
2020-11-05 18:37:30 -08:00
..
accounting SPDX patches for 5.7-rc1. 2020-04-03 13:12:26 -07:00
arch parisc: Add MAP_UNINITIALIZED define 2020-10-15 08:10:39 +02:00
bootconfig Updates for tracing and bootconfig: 2020-10-15 15:51:28 -07:00
bpf Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-10-05 18:40:01 -07:00
build perf tools changes for v5.10: 1st batch 2020-10-17 11:47:46 -07:00
cgroup blk-iocost: update iocost_monitor.py 2020-09-01 19:38:33 -06:00
debugging
edid tools/edid: Move EDID data sets from Documentation/ 2020-02-19 04:10:32 -07:00
firewire
firmware
gpio tools: gpio: add debounce support to gpio-event-mon 2020-09-30 10:57:30 +02:00
hv tools: hv: change http to https in hv_kvp_daemon.c 2020-07-06 10:46:23 +00:00
iio iio: add IIO_MOD_O2 modifier 2020-08-22 10:53:12 +01:00
include bpf: Fix bpf_redirect_neigh helper api to support supplying nexthop 2020-10-22 01:28:54 +02:00
io_uring tools/io_uring: fix compile breakage 2020-09-21 07:50:58 -06:00
kvm/kvm_stat tools/kvm_stat: add sample systemd unit file 2020-04-21 09:13:12 -04:00
laptop change email address for Pali Rohár 2020-04-10 15:36:22 -07:00
leds .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
lib libbpf: Implement basic split BTF support 2020-11-05 18:37:30 -08:00
memory-model tools/memory-model: Expand the cheatsheet.txt notion of relaxed 2020-09-04 11:58:15 -07:00
objtool objtool changes for v5.10: 2020-10-14 10:13:37 -07:00
pci tools: PCI: Add 'e' to clear IRQ 2020-04-02 17:57:10 +01:00
pcmcia .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
perf perf tools changes for v5.10: 1st batch 2020-10-17 11:47:46 -07:00
power linux-kselftest-fixes-5.10-rc1 2020-10-14 14:23:51 -07:00
scripts Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-03-25 18:58:11 -07:00
spi spi: tools: Make default_tx/rx and input_tx static 2020-06-11 16:27:24 +01:00
testing selftest/bpf: Relax btf_dedup test checks 2020-11-05 18:37:30 -08:00
thermal/tmon - Convert tsens configuration DT binding to yaml (Rajeshwari) 2020-04-07 20:00:16 -07:00
time
usb tools: usb: move to tools buildsystem 2020-08-19 14:11:44 +02:00
virtio virtio: fixes, features 2020-08-11 14:34:17 -07:00
vm mm: Add PG_arch_2 page flag 2020-09-04 12:46:06 +01:00
wmi
Makefile bpf: Compile resolve_btfids tool at kernel compilation start 2020-07-13 10:42:02 -07:00