linux/tools
Jose E. Marchesi 675b4e24bc bpf: Temporarily define BPF_NO_PRESEVE_ACCESS_INDEX for GCC
The vmlinux.h file generated by bpftool makes use of compiler pragmas
in order to install the CO-RE preserve_access_index in all the struct
types derived from the BTF info:

  #ifndef __VMLINUX_H__
  #define __VMLINUX_H__

  #ifndef BPF_NO_PRESERVE_ACCESS_INDEX
  #pragma clang attribute push (__attribute__((preserve_access_index)), apply_t = record
  #endif

  [... type definitions generated from kernel BTF ... ]

  #ifndef BPF_NO_PRESERVE_ACCESS_INDEX
  #pragma clang attribute pop
  #endif

The `clang attribute push/pop' pragmas are specific to clang/llvm and
are not supported by GCC.

At the moment the BTF dumping services in libbpf do not support
dicriminating between types dumped because they are directly referred
and types dumped because they are dependencies.  A suitable API is
being worked now. See [1] and [2].

In the interim, this patch changes the selftests/bpf Makefile so it
passes -DBPF_NO_PRESERVE_ACCESS_INDEX to GCC when it builds the
selftests.  This workaround is temporary, and may have an impact on
the results of the GCC-built tests.

[1] https://lore.kernel.org/bpf/20240503111836.25275-1-jose.marchesi@oracle.com/T/#u
[2] https://lore.kernel.org/bpf/20240504205510.24785-1-jose.marchesi@oracle.com/T/#u

Tested in bpf-next master.
No regressions.

Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240507095011.15867-1-jose.marchesi@oracle.com
2024-05-07 14:40:00 -07:00
..
accounting
arch tools/include: Sync arm64 asm/cputype.h with the kernel sources 2024-04-11 10:38:29 -07:00
bootconfig
bpf bpftool, selftests/hid/bpf: Fix 29 clang warnings 2024-05-06 14:39:36 -07:00
build perf: build: introduce the libcapstone 2024-02-20 18:06:25 -08:00
certs
cgroup
counter
crypto crypto: ccp - Update return values for some unit tests 2024-02-24 08:41:20 +08:00
debugging
firewire
firmware
gpio
hv hv/hv_kvp_daemon: Handle IPv4 and Ipv6 combination for keyfile format 2024-04-10 21:25:40 +00:00
iio
include bpf: Add support for kprobe session attach 2024-04-30 09:45:53 -07:00
kvm/kvm_stat
laptop
leds
lib libbpf: Avoid casts from pointers to enums in bpf_tracing.h 2024-05-02 22:58:58 -07:00
memory-model
mm tools/mm: add thpmaps script to dump THP usage info 2024-02-22 10:24:38 -08:00
net/ynl tools: ynl: don't append doc of missing type directly to the type 2024-04-26 17:35:03 -07:00
objtool objtool: Fix compile failure when using the x32 compiler 2024-03-30 22:12:37 +01:00
pci
pcmcia
perf Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2024-04-25 12:41:37 -07:00
power Turbostat version 2024.04.10 2024-04-10 13:13:27 -07:00
rcu
scripts treewide: remove meaningless assignments in Makefiles 2024-02-23 14:19:07 -08:00
spi
testing bpf: Temporarily define BPF_NO_PRESEVE_ACCESS_INDEX for GCC 2024-05-07 14:40:00 -07:00
thermal
time
tracing tools/rtla: Add -U/--user-load option to timerlat 2024-03-20 05:39:06 +01:00
usb
verification tools/verification: Use tools/build makefiles on rv 2024-03-20 05:39:06 +01:00
virtio tools: virtio: introduce vhost_net_test 2024-03-05 11:38:14 +01:00
wmi
workqueue workqueue: Implement BH workqueues to eventually replace tasklets 2024-02-04 11:28:06 -10:00
Makefile tools/Makefile: remove cgroup target 2024-03-26 11:07:21 -07:00