From patchwork Sun Nov 12 01:06:04 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 13453232 X-Patchwork-Delegate: bpf@iogearbox.net Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D307015B6 for ; Sun, 12 Nov 2023 01:06:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=none Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com [67.231.145.42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1089630F9 for ; Sat, 11 Nov 2023 17:06:51 -0800 (PST) Received: from pps.filterd (m0044012.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 3AC0qDJU013669 for ; Sat, 11 Nov 2023 17:06:50 -0800 Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 3ua86tajm2-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Sat, 11 Nov 2023 17:06:50 -0800 Received: from twshared15991.38.frc1.facebook.com (2620:10d:c0a8:1c::1b) by mail.thefacebook.com (2620:10d:c0a8:82::b) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.34; Sat, 11 Nov 2023 17:06:49 -0800 Received: by devbig019.vll3.facebook.com (Postfix, from userid 137359) id 8556B3B5D525B; Sat, 11 Nov 2023 17:06:41 -0800 (PST) From: Andrii Nakryiko To: , , , CC: , Subject: [PATCH v2 bpf-next 08/13] selftests/bpf: adjust OP_EQ/OP_NE handling to use subranges for branch taken Date: Sat, 11 Nov 2023 17:06:04 -0800 Message-ID: <20231112010609.848406-9-andrii@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231112010609.848406-1-andrii@kernel.org> References: <20231112010609.848406-1-andrii@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-GUID: XbXwKNkXBFlt4NMljEZbiLb-rJkuQ8fH X-Proofpoint-ORIG-GUID: XbXwKNkXBFlt4NMljEZbiLb-rJkuQ8fH X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.987,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2023-11-11_21,2023-11-09_01,2023-05-22_02 X-Patchwork-Delegate: bpf@iogearbox.net Similar to kernel-side BPF verifier logic enhancements, use 32-bit subrange knowledge for is_branch_taken() logic in reg_bounds selftests. Signed-off-by: Andrii Nakryiko Acked-by: Eduard Zingerman --- .../selftests/bpf/prog_tests/reg_bounds.c | 30 ++++++++++++++++--- 1 file changed, 26 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/reg_bounds.c b/tools/testing/selftests/bpf/prog_tests/reg_bounds.c index 7a524b381ed3..10f3b6898274 100644 --- a/tools/testing/selftests/bpf/prog_tests/reg_bounds.c +++ b/tools/testing/selftests/bpf/prog_tests/reg_bounds.c @@ -748,16 +748,38 @@ static int reg_state_branch_taken_op(enum num_t t, struct reg_state *x, struct r /* OP_EQ and OP_NE are sign-agnostic */ enum num_t tu = t_unsigned(t); enum num_t ts = t_signed(t); - int br_u, br_s; + int br_u, br_s, br; br_u = range_branch_taken_op(tu, x->r[tu], y->r[tu], op); br_s = range_branch_taken_op(ts, x->r[ts], y->r[ts], op); if (br_u >= 0 && br_s >= 0 && br_u != br_s) ASSERT_FALSE(true, "branch taken inconsistency!\n"); - if (br_u >= 0) - return br_u; - return br_s; + + /* if 64-bit ranges are indecisive, use 32-bit subranges to + * eliminate always/never taken branches, if possible + */ + if (br_u == -1 && (t == U64 || t == S64)) { + br = range_branch_taken_op(U32, x->r[U32], y->r[U32], op); + /* we can only reject for OP_EQ, never take branch + * based on lower 32 bits + */ + if (op == OP_EQ && br == 0) + return 0; + /* for OP_NEQ we can be conclusive only if lower 32 bits + * differ and thus inequality branch is always taken + */ + if (op == OP_NE && br == 1) + return 1; + + br = range_branch_taken_op(S32, x->r[S32], y->r[S32], op); + if (op == OP_EQ && br == 0) + return 0; + if (op == OP_NE && br == 1) + return 1; + } + + return br_u >= 0 ? br_u : br_s; } return range_branch_taken_op(t, x->r[t], y->r[t], op); }