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From: Krzesimir Nowak <krzesimir@kinvolk.io>
To: bpf@vger.kernel.org
Cc: iago@kinvolk.io, alban@kinvolk.io,
	Krzesimir Nowak <krzesimir@kinvolk.io>,
	Shuah Khan <shuah@kernel.org>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
	Yonghong Song <yhs@fb.com>, Andrey Ignatov <rdna@fb.com>,
	Jiong Wang <jiong.wang@netronome.com>,
	Jakub Kicinski <jakub.kicinski@netronome.com>,
	linux-kselftest@vger.kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH bpf v1 1/3] selftests/bpf: Test correctness of narrow 32bit read on 64bit field
Date: Wed, 15 May 2019 15:47:26 +0200	[thread overview]
Message-ID: <20190515134731.12611-2-krzesimir@kinvolk.io> (raw)
In-Reply-To: <20190515134731.12611-1-krzesimir@kinvolk.io>

Test the correctness of the 32bit narrow reads by reading both halves
of the 64 bit field and doing a binary or on them to see if we get the
original value.

This isn't really tested - the program is not being run, because
BPF_PROG_TYPE_PERF_EVENT is not supported by bpf_test_run_prog.

Signed-off-by: Krzesimir Nowak <krzesimir@kinvolk.io>
---
 tools/testing/selftests/bpf/verifier/var_off.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/tools/testing/selftests/bpf/verifier/var_off.c b/tools/testing/selftests/bpf/verifier/var_off.c
index 8504ac937809..2668819dcc85 100644
--- a/tools/testing/selftests/bpf/verifier/var_off.c
+++ b/tools/testing/selftests/bpf/verifier/var_off.c
@@ -246,3 +246,18 @@
 	.result = ACCEPT,
 	.prog_type = BPF_PROG_TYPE_LWT_IN,
 },
+{
+	"32bit loads of a 64bit field (both least and most significant words)",
+	.insns = {
+	BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_1, offsetof(struct bpf_perf_event_data, sample_period)),
+	BPF_LDX_MEM(BPF_W, BPF_REG_5, BPF_REG_1, offsetof(struct bpf_perf_event_data, sample_period) + 4),
+	BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, offsetof(struct bpf_perf_event_data, sample_period)),
+	BPF_ALU64_IMM(BPF_LSH, BPF_REG_4, 32),
+	BPF_ALU64_REG(BPF_OR, BPF_REG_4, BPF_REG_5),
+	BPF_ALU64_REG(BPF_XOR, BPF_REG_4, BPF_REG_6),
+	BPF_MOV64_REG(BPF_REG_0, BPF_REG_4),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.prog_type = BPF_PROG_TYPE_PERF_EVENT,
+},
-- 
2.20.1


  reply	other threads:[~2019-05-15 13:48 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-15 13:47 [PATCH bpf v1 0/3] Test the 32bit narrow reads Krzesimir Nowak
2019-05-15 13:47 ` Krzesimir Nowak [this message]
2019-05-23 16:02   ` [PATCH bpf v1 1/3] selftests/bpf: Test correctness of narrow 32bit read on 64bit field Daniel Borkmann
2019-05-15 13:47 ` [PATCH bpf v1 2/3] selftests/bpf: Print a message when tester could not run a program Krzesimir Nowak
2019-05-15 21:45   ` Jakub Kicinski
2019-05-16  9:29     ` Krzesimir Nowak
2019-05-16 15:50       ` Jakub Kicinski
2019-05-16 16:21         ` Krzesimir Nowak
2019-05-16 16:54           ` Jakub Kicinski
2019-05-15 13:47 ` [PATCH bpf v1 3/3] selftests/bpf: Avoid a clobbering of errno Krzesimir Nowak
2019-05-15 21:50   ` Jakub Kicinski
2019-05-16  9:31     ` Krzesimir Nowak

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