linux/tools
Andrii Nakryiko 1cf5b23988 bpftool: Apply preserve_access_index attribute to all types in BTF dump
This patch makes structs and unions, emitted through BTF dump, automatically
CO-RE-relocatable (unless disabled with `#define BPF_NO_PRESERVE_ACCESS_INDEX`,
specified before including generated header file).

This effectivaly turns usual bpf_probe_read() call into equivalent of
bpf_core_read(), by automatically applying builtin_preserve_access_index to
any field accesses of types in generated C types header.

This is especially useful for tp_btf/fentry/fexit BPF program types. They
allow direct memory access, so BPF C code just uses straightfoward a->b->c
access pattern to read data from kernel. But without kernel structs marked as
CO-RE relocatable through preserve_access_index attribute, one has to enclose
all the data reads into a special __builtin_preserve_access_index code block,
like so:

__builtin_preserve_access_index(({
    x = p->pid; /* where p is struct task_struct *, for example */
}));

This is very inconvenient and obscures the logic quite a bit. By marking all
auto-generated types with preserve_access_index attribute the above code is
reduced to just a clean and natural `x = p->pid;`.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200113073143.1779940-5-andriin@fb.com
2020-01-13 17:48:13 -08:00
..
accounting
arch tools arch x86: Sync asm/cpufeatures.h with the kernel sources 2019-12-02 15:20:05 -03:00
bpf bpftool: Apply preserve_access_index attribute to all types in BTF dump 2020-01-13 17:48:13 -08:00
build perf tools: Allow to link with libbpf dynamicaly 2019-11-26 11:17:45 -03:00
cgroup iocost_monitor: Report debt 2019-09-10 12:31:39 -06:00
debugging
firewire
firmware Driver Core and debugfs changes for 5.3-rc1 2019-07-12 12:24:03 -07:00
gpio tools: gpio: Correctly add make dependencies for gpio_utils 2019-11-13 13:46:04 +01:00
hv tools: hv: add vmbus testing tool 2019-11-21 20:10:44 -05:00
iio tools: iio: Correctly add make dependency for iio_utils 2019-11-10 17:11:06 +00:00
include tools: Sync uapi/linux/if_link.h 2020-01-13 17:48:12 -08:00
io_uring
kvm/kvm_stat
laptop
leds leds: core: Add support for composing LED class device names 2019-07-25 20:07:52 +02:00
lib libbpf: Clean up bpf_helper_defs.h generation output 2020-01-13 17:48:13 -08:00
memory-model tools/memory-model/Documentation: Add plain accesses and data races to explanation.txt 2019-10-05 11:59:44 -07:00
nfsd
objtool Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-11-26 15:04:47 -08:00
pci tools: PCI: Fix fd leakage 2019-10-29 12:04:18 +00:00
pcmcia
perf perf vendor events s390: Remove name from L1D_RO_EXCL_WRITES description 2019-12-16 13:40:26 -03:00
power platform-drivers-x86 for v5.5-1 2019-12-01 18:24:25 -08:00
scripts perf build: Do not use -Wshadow on gcc < 4.8 2019-07-23 09:04:54 -03:00
spi
testing selftests/bpf: Conform selftests/bpf Makefile output to libbpf and bpftool 2020-01-13 17:48:13 -08:00
thermal/tmon
time
usb usbip: tools: fix fd leakage in the function of read_attr_usbip_status 2019-11-07 11:25:01 +01:00
virtio tools/virtio: xen stub 2019-10-13 09:38:27 -04:00
vm tools/vm/slabinfo: add sorting info to help menu 2019-07-12 11:05:46 -07:00
wmi
Makefile tools: Keep list of tools in alphabetical order 2019-08-14 10:59:59 -03:00