linux/tools
Andrii Nakryiko 44ad23dfbc libbpf: Handle BTF pointer sizes more carefully
With libbpf and BTF it is pretty common to have libbpf built for one
architecture, while BTF information was generated for a different architecture
(typically, but not always, BPF). In such case, the size of a pointer might
differ betweem architectures. libbpf previously was always making an
assumption that pointer size for BTF is the same as native architecture
pointer size, but that breaks for cases where libbpf is built as 32-bit
library, while BTF is for 64-bit architecture.

To solve this, add heuristic to determine pointer size by searching for `long`
or `unsigned long` integer type and using its size as a pointer size. Also,
allow to override the pointer size with a new API btf__set_pointer_size(), for
cases where application knows which pointer size should be used. User
application can check what libbpf "guessed" by looking at the result of
btf__pointer_size(). If it's not 0, then libbpf successfully determined a
pointer size, otherwise native arch pointer size will be used.

For cases where BTF is parsed from ELF file, use ELF's class (32-bit or
64-bit) to determine pointer size.

Fixes: 8a138aed4a ("bpf: btf: Add BTF support to libbpf")
Fixes: 351131b51c ("libbpf: add btf_dump API for BTF-to-C conversion")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200813204945.1020225-5-andriin@fb.com
2020-08-13 16:45:41 -07:00
..
accounting
arch tools arch kvm: Sync kvm headers with the kernel sources 2020-07-17 09:39:16 -03:00
bootconfig tools/bootconfig: Add testcase for show-command and quotes test 2020-06-16 21:21:03 -04:00
bpf tools/bpftool: Fix compilation warnings in 32-bit mode 2020-08-13 16:45:41 -07:00
build tools, build: Propagate build failures from tools/build/Makefile.build 2020-08-03 16:15:40 +02:00
cgroup iocost_monitor: start from the oldest usage index 2020-07-30 11:45:29 -06:00
debugging
edid
firewire
firmware
gpio tools: gpio: fix spurious close warning in gpio-event-mon 2020-07-12 10:22:01 +02:00
hv tools: hv: change http to https in hv_kvp_daemon.c 2020-07-06 10:46:23 +00:00
iio
include tools/bpf: Support new uapi for map element bpf iterator 2020-08-06 16:39:14 -07:00
io_uring io_uring: change the poll type to be 32-bits 2020-06-21 20:44:00 -06:00
kvm/kvm_stat tools/kvm_stat: add sample systemd unit file 2020-04-21 09:13:12 -04:00
laptop
leds
lib libbpf: Handle BTF pointer sizes more carefully 2020-08-13 16:45:41 -07:00
memory-model These were the main changes in this cycle: 2020-08-03 14:39:35 -07:00
nfsd
objtool Misc updates: 2020-08-03 14:45:33 -07:00
pci
pcmcia
perf Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-08-02 01:02:12 -07:00
power ACPI updates for 5.9-rc1 2020-08-03 20:37:22 -07:00
scripts
spi spi: tools: Make default_tx/rx and input_tx static 2020-06-11 16:27:24 +01:00
testing selftest/bpf: Fix compilation warnings in 32-bit mode 2020-08-13 16:45:41 -07:00
thermal/tmon
time
usb tools: usb: usbip: Replace HTTP links with HTTPS ones 2020-07-15 16:33:51 +02:00
virtio compiler: Remove uninitialized_var() macro 2020-07-16 12:35:31 -07:00
vm tools/vm/page_owner_sort.c: filter out unneeded line 2020-06-03 20:09:49 -07:00
wmi
Makefile bpf: Compile resolve_btfids tool at kernel compilation start 2020-07-13 10:42:02 -07:00