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>

Test verifier/xdp.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-43-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/xadd.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-42-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/var_off.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-41-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/value_or_null.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-40-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/value.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-39-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/value_adj_spill.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-38-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/uninit.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-37-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/stack_ptr.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-36-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/spill_fill.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-35-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/ringbuf.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-34-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/raw_tp_writable.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-33-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/raw_stack.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-32-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/meta_access.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-31-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/masking.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-30-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/map_ret_val.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-29-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/map_ptr.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-28-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/leak_ptr.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-27-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/ld_ind.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-26-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/int_ptr.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-25-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/helper_value_access.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-24-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/helper_restricted.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-23-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/helper_packet_access.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-22-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/helper_access_var_len.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-21-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/div_overflow.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-20-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/div0.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-19-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/direct_stack_access_wraparound.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-18-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/ctx_sk_msg.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-17-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/const_or.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-16-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/cgroup_storage.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-15-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/cgroup_skb.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-14-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/cgroup_inv_retcode.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-13-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/cfg.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-12-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/bounds_mix_sign_unsign.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-11-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/bounds_deduction.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-10-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/basic_stack.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-9-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/array_access.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-8-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Test verifier/and.c automatically converted to use inline assembly.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-7-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

prog_tests/verifier.c would be used as a host for verifier/*.c tests
migrated to use inline assembly and run from test_progs.

The run_test_aux() function mimics the test_verifier behavior
dropping CAP_SYS_ADMIN upon entry.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-6-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Extends test_loader.c:test_loader__run_subtests() by allowing to
execute BPF_PROG_TEST_RUN bpf command for selected programs.
This is similar to functionality provided by test_verifier.

Adds the following new attributes controlling test_loader behavior:

  __retval(...)
  __retval_unpriv(...)

* If any of these attributes is present, the annotated program would
  be executed using libbpf's bpf_prog_test_run_opts() function.
* If __retval is present, the test run would be done for program
  loaded in privileged mode.
* If __retval_unpriv is present, the test run would be done for
  program loaded in unprivileged mode.
* To mimic test_verifier behavior, the actual run is initiated in
  privileged mode.
* The value returned by a test run is compared against retval
  parameter.

The retval attribute takes one of the following parameters:
- a decimal number
- a hexadecimal number (must start from '0x')
- any of a three special literals (provided for compatibility with
  test_verifier):
  - INT_MIN
  - POINTER_VALUE
  - TEST_DATA_LEN

An example of the attribute usage:

  SEC("socket")
  __description("return 42")
  __success __success_unpriv __retval(42)
  __naked void the_42_test(void)
  {
          asm volatile ("                                 \
          r0 = 42;                                        \
          exit;                                           \
  "       ::: __clobber_all);
  }
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230325025524.144043-5-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>