selftests/bpf: Validate libbpf's auto-sizing of LD/ST/STX instructions

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Add selftests validating libbpf's auto-resizing of load/store instructions
when used with CO-RE relocations. An explicit and manual approach with using
bpf_core_read() is also demonstrated and tested. Separate BPF program is
supposed to fail due to using signed integers of sizes that differ from
kernel's sizes.

To reliably simulate 32-bit BTF (i.e., the one with sizeof(long) ==
sizeof(void *) == 4), selftest generates its own custom BTF and passes it as
a replacement for real kernel BTF. This allows to test 32/64-bitness mix on
all architectures.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20201008001025.292064-5-andrii@kernel.org

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Andrii Nakryiko 2020-10-07 17:10:24 -07:00 • committed by Alexei Starovoitov

parent 2b7d88c2b5

commit 888d83b961

2 changed files with 397 additions and 0 deletions

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225

tools/testing/selftests/bpf/prog_tests/core_autosize.c

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172

tools/testing/selftests/bpf/progs/test_core_autosize.c

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