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| author | Alexei Starovoitov <ast@kernel.org> | 2026-03-10 21:51:18 +0300 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2026-03-10 21:51:27 +0300 |
| commit | 437350df8640bf0535b74a3d8bade6f707940027 (patch) | |
| tree | 977d0899d15ac4412007b7c2df54b734e8d5763b /tools/testing | |
| parent | bd2e02e3c9215305dfa344c050d5822f19929cf7 (diff) | |
| parent | 6a1c9a442f634e7b95c5ad0927870335b1ce299e (diff) | |
| download | linux-437350df8640bf0535b74a3d8bade6f707940027.tar.xz | |
Merge branch 'bpf-support-for-non_null-ptr-detection-with-jeq-jne-with-register-operand'
Cupertino Miranda says:
====================
bpf: support for non_null ptr detection with JEQ/JNE with register operand
Changes from v1:
- Corrected typos in commit messages.
- Fixed indentation.
- Replaced text by simpler version suggested by Eduard.
Changes from v2:
- Small fixes after AI patch checker complaints.
Changes from v3:
- Removed log file. No idea how that got added.
====================
Link: https://patch.msgid.link/20260304195018.181396-1-cupertino.miranda@oracle.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'tools/testing')
| -rw-r--r-- | tools/testing/selftests/bpf/progs/verifier_jeq_infer_not_null.c | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/verifier_jeq_infer_not_null.c b/tools/testing/selftests/bpf/progs/verifier_jeq_infer_not_null.c index bf16b00502f2..3d1e8de4390c 100644 --- a/tools/testing/selftests/bpf/progs/verifier_jeq_infer_not_null.c +++ b/tools/testing/selftests/bpf/progs/verifier_jeq_infer_not_null.c @@ -210,4 +210,58 @@ l0_%=: /* return 0; */ \ : __clobber_all); } +/* Verified that we can detect the pointer as non_null when comparing with + * register with value 0. JEQ test case. + */ +SEC("xdp") +__success __log_level(2) +/* to make sure the branch is not falsely predicted*/ +__msg("r0 = *(u32 *)(r0 +0)") +__msg("from 7 to 9") +__naked void jeq_reg_reg_null_check(void) +{ + asm volatile (" \ + *(u32*)(r10 - 8) = 0; \ + r1 = %[map_xskmap] ll; \ + r2 = r10; \ + r2 += -8; \ + call %[bpf_map_lookup_elem]; \ + r1 = 0; \ + if r0 == r1 goto 1f; \ + r0 = *(u32*)(r0 +0); \ +1: r0 = 0; \ + exit; \ +" : + : __imm(bpf_map_lookup_elem), + __imm_addr(map_xskmap) + : __clobber_all); +} + +/* Same as above but for JNE. + */ +SEC("xdp") +__success __log_level(2) +/* to make sure the branch is not falsely predicted*/ +__msg("r0 = *(u32 *)(r0 +0)") +__msg("from 7 to 9") +__naked void jne_reg_reg_null_check(void) +{ + asm volatile (" \ + *(u32*)(r10 - 8) = 0; \ + r1 = %[map_xskmap] ll; \ + r2 = r10; \ + r2 += -8; \ + call %[bpf_map_lookup_elem]; \ + r1 = 0; \ + if r0 != r1 goto 1f; \ + goto 2f; \ +1: r0 = *(u32*)(r0 +0); \ +2: r0 = 0; \ + exit; \ +" : + : __imm(bpf_map_lookup_elem), + __imm_addr(map_xskmap) + : __clobber_all); +} + char _license[] SEC("license") = "GPL"; |