e99360762a
Eduard Zingerman says:
====================
This is a follow up for RFC [1]. It migrates a first batch of 38
verifier/*.c tests to inline assembly and use of ./test_progs for
actual execution. The migration is done by a python script (see [2]).
Each migrated verifier/xxx.c file is mapped to progs/verifier_xxx.c
plus an entry in the prog_tests/verifier.c. One patch per each file.
A few patches at the beginning of the patch-set extend test_loader
with necessary functionality, mainly:
- support for tests execution in unprivileged mode;
- support for test runs for test programs.
Migrated tests could be selected for execution using the following filter:
./test_progs -a verifier_*
An example of the migrated test:
SEC("xdp")
__description("XDP pkt read, pkt_data' > pkt_end, corner case, good access")
__success __retval(0) __flag(BPF_F_ANY_ALIGNMENT)
__naked void end_corner_case_good_access_1(void)
{
asm volatile (" \
r2 = *(u32*)(r1 + %[xdp_md_data]); \
r3 = *(u32*)(r1 + %[xdp_md_data_end]); \
r1 = r2; \
r1 += 8; \
if r1 > r3 goto l0_%=; \
r0 = *(u64*)(r1 - 8); \
l0_%=: r0 = 0; \
exit; \
" :
: __imm_const(xdp_md_data, offsetof(struct xdp_md, data)),
__imm_const(xdp_md_data_end, offsetof(struct xdp_md, data_end))
: __clobber_all);
}
Changes compared to RFC:
- test_loader.c is extended to support test program runs;
- capabilities handling now matches behavior of test_verifier;
- BPF_ST_MEM instructions are automatically replaced by BPF_STX_MEM
instructions to overcome current clang limitations;
- tests styling updates according to RFC feedback;
- 38 migrated files are included instead of 1.
I used the following means for testing:
- migration tool itself has a set of self-tests;
- migrated tests are passing;
- manually compared each old/new file side-by-side.
While doing side-by-side comparison I've noted a few defects in the
original tests:
- and.c:
- One of the jump targets is off by one;
- BPF_ST_MEM wrong OFF/IMM ordering;
- array_access.c:
- BPF_ST_MEM wrong OFF/IMM ordering;
- value_or_null.c:
- BPF_ST_MEM wrong OFF/IMM ordering.
These defects would be addressed separately.
[1] RFC
https://lore.kernel.org/bpf/20230123145148.2791939-1-eddyz87@gmail.com/
[2] Migration tool
https://github.com/eddyz87/verifier-tests-migrator
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
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https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
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