BPF List
 help / color / mirror / Atom feed
* [PATCH bpf-next v3 0/8] __jited test tag to check disassembly after jit
@ 2024-08-20 10:23 Eduard Zingerman
  2024-08-20 10:23 ` [PATCH bpf-next v3 1/8] selftests/bpf: less spam in the log for message matching Eduard Zingerman
                   ` (9 more replies)
  0 siblings, 10 replies; 13+ messages in thread
From: Eduard Zingerman @ 2024-08-20 10:23 UTC (permalink / raw)
  To: bpf, ast
  Cc: andrii, daniel, martin.lau, kernel-team, yonghong.song, hffilwlqm,
	Eduard Zingerman

Some of the logic in the BPF jits might be non-trivial.
It might be useful to allow testing this logic by comparing
generated native code with expected code template.
This patch set adds a macro __jited() that could be used for
test_loader based tests in a following manner:

    SEC("tp")
    __arch_x86_64
    __jited("   endbr64")
    __jited("   nopl    (%rax,%rax)")
    __jited("   xorq    %rax, %rax")
    ...
    __naked void some_test(void) { ... }

Also add a test for jit code generated for tail calls handling to
demonstrate the feature.

The feature uses LLVM libraries to do the disassembly.
At selftests compilation time Makefile detects if these libraries are
available. When libraries are not available tests using __jit_x86()
are skipped. 
Current CI environment does not include llvm development libraries,
but changes to add these are trivial.

This was previously discussed here:
https://lore.kernel.org/bpf/20240718205158.3651529-1-yonghong.song@linux.dev/

Patch-set includes a few auxiliary steps:
- patches #2 and #3 fix a few bugs in test_loader behaviour;
- patch #4 replaces __regex macro with ability to specify regular
  expressions in __msg and __xlated using "{{" "}}" escapes;
- patch #8 updates __xlated to match disassembly lines consequently,
  same way as __jited does.

Changes v2->v3:
- changed macro name from __jit_x86 to __jited with __arch_* to
  specify disassembly arch (Yonghong);
- __jited matches disassembly lines consequently with "..."
  allowing to skip some number of lines (Andrii);
- __xlated matches disassembly lines consequently, same as __jited;
- "{{...}}" regex brackets instead of __regex macro;
- bug fixes for old commits.

Changes v1->v2:
- stylistic changes suggested by Yonghong;
- fix for -Wformat-truncation related warning when compiled with
  llvm15 (Yonghong).

v1: https://lore.kernel.org/bpf/20240809010518.1137758-1-eddyz87@gmail.com/
v2: https://lore.kernel.org/bpf/20240815205449.242556-1-eddyz87@gmail.com/

Eduard Zingerman (8):
  selftests/bpf: less spam in the log for message matching
  selftests/bpf: correctly move 'log' upon successful match
  selftests/bpf: fix to avoid __msg tag de-duplication by clang
  selftests/bpf: replace __regex macro with "{{...}}" patterns
  selftests/bpf: utility function to get program disassembly after jit
  selftests/bpf: __jited test tag to check disassembly after jit
  selftests/bpf: validate jit behaviour for tail calls
  selftests/bpf: validate __xlated same way as __jited

 tools/testing/selftests/bpf/.gitignore        |   1 +
 tools/testing/selftests/bpf/Makefile          |  48 ++-
 .../selftests/bpf/jit_disasm_helpers.c        | 234 ++++++++++++
 .../selftests/bpf/jit_disasm_helpers.h        |  10 +
 .../selftests/bpf/prog_tests/verifier.c       |   2 +
 tools/testing/selftests/bpf/progs/bpf_misc.h  |  55 ++-
 .../testing/selftests/bpf/progs/dynptr_fail.c |   6 +-
 .../testing/selftests/bpf/progs/rbtree_fail.c |   2 +-
 .../bpf/progs/refcounted_kptr_fail.c          |   4 +-
 .../selftests/bpf/progs/verifier_nocsr.c      |  53 ++-
 .../selftests/bpf/progs/verifier_spill_fill.c |   8 +-
 .../bpf/progs/verifier_tailcall_jit.c         | 105 ++++++
 tools/testing/selftests/bpf/test_loader.c     | 357 +++++++++++++-----
 13 files changed, 772 insertions(+), 113 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/jit_disasm_helpers.c
 create mode 100644 tools/testing/selftests/bpf/jit_disasm_helpers.h
 create mode 100644 tools/testing/selftests/bpf/progs/verifier_tailcall_jit.c

-- 
2.45.2


^ permalink raw reply	[flat|nested] 13+ messages in thread
end of thread, other threads:[~2024-08-21 18:13 UTC | newest]

Thread overview: 13+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2024-08-20 10:23 [PATCH bpf-next v3 0/8] __jited test tag to check disassembly after jit Eduard Zingerman
2024-08-20 10:23 ` [PATCH bpf-next v3 1/8] selftests/bpf: less spam in the log for message matching Eduard Zingerman
2024-08-20 10:23 ` [PATCH bpf-next v3 2/8] selftests/bpf: correctly move 'log' upon successful match Eduard Zingerman
2024-08-20 10:23 ` [PATCH bpf-next v3 3/8] selftests/bpf: fix to avoid __msg tag de-duplication by clang Eduard Zingerman
2024-08-20 10:23 ` [PATCH bpf-next v3 4/8] selftests/bpf: replace __regex macro with "{{...}}" patterns Eduard Zingerman
2024-08-20 10:23 ` [PATCH bpf-next v3 5/8] selftests/bpf: utility function to get program disassembly after jit Eduard Zingerman
2024-08-21 18:07   ` Alexei Starovoitov
2024-08-21 18:13     ` Eduard Zingerman
2024-08-20 10:23 ` [PATCH bpf-next v3 6/8] selftests/bpf: __jited test tag to check " Eduard Zingerman
2024-08-20 10:23 ` [PATCH bpf-next v3 6/8] selftests/bpf: __jited_x86 test tag to check x86 assembly " Eduard Zingerman
2024-08-20 10:23 ` [PATCH bpf-next v3 7/8] selftests/bpf: validate jit behaviour for tail calls Eduard Zingerman
2024-08-20 10:23 ` [PATCH bpf-next v3 8/8] selftests/bpf: validate __xlated same way as __jited Eduard Zingerman
2024-08-21 18:10 ` [PATCH bpf-next v3 0/8] __jited test tag to check disassembly after jit patchwork-bot+netdevbpf

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox