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(unknown []) by gzga-smtp-mtada-g0-4 (Coremail) with SMTP id _____wDX0bXE0I1oWsxLJQ--.56694S4; Sat, 02 Aug 2025 16:48:07 +0800 (CST) From: Jiawei Zhao To: ast@kernel.org Cc: daniel@iogearbox.net, andrii@kernel.org, yonghong.song@linux.dev, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v6 2/2] selftests/bpf: Force -O2 for USDT selftests to cover SIB handling logic Date: Sat, 2 Aug 2025 08:48:03 +0000 Message-ID: <20250802084803.108777-3-phoenix500526@163.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250802084803.108777-1-phoenix500526@163.com> References: <20250802084803.108777-1-phoenix500526@163.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: _____wDX0bXE0I1oWsxLJQ--.56694S4 X-Coremail-Antispam: 1Uf129KBjvJXoWxWw4ktFy5WrWDCF4kGw48JFb_yoW5tw45pa 95Ww1UtFySq3W7JFs3ZrnrXr45WFs7JFWFyr1UXryFvr4kJF97XFZ7t3yUKFnxW393Xaya v392gry7GF45AwUanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07jzUDJUUUUU= X-CM-SenderInfo: pskrv0dl0viiqvswqiywtou0bp/1tbiFAGdiGiNynRtRQAAsz Content-Type: text/plain; charset="utf-8" When using GCC on x86-64 to compile an usdt prog with -O1 or higher optimization, the compiler will generate SIB addressing mode for global array and PC-relative addressing mode for global variable, e.g. "1@-96(%rbp,%rax,8)" and "-1@4+t1(%rip)". In this patch: - force -O2 optimization for usdt.test.o to generate SIB addressing usdt argument spec. - change the global variable t1 to a local variable, to avoid compiler generating PC-relative addressing mode for it. Signed-off-by: Jiawei Zhao --- tools/testing/selftests/bpf/Makefile | 8 ++++++++ tools/testing/selftests/bpf/prog_tests/usdt.c | 18 ++++++++++++------ 2 files changed, 20 insertions(+), 6 deletions(-) diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests= /bpf/Makefile index 910d8d6402ef..4b77d06d5c42 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -759,6 +759,14 @@ TRUNNER_BPF_BUILD_RULE :=3D $$(error no BPF objects sh= ould be built) TRUNNER_BPF_CFLAGS :=3D $(eval $(call DEFINE_TEST_RUNNER,test_maps)) =20 +# Force usdt.c to use -O2 optimization to generate SIB addressing +# Only apply on x86 architecture where SIB addressing is relevant +ifeq ($(ARCH), x86) +$(OUTPUT)/usdt.test.o: CFLAGS:=3D$(subst O0,O2,$(CFLAGS)) +$(OUTPUT)/cpuv4/usdt.test.o: CFLAGS:=3D$(subst O0,O2,$(CFLAGS)) +$(OUTPUT)/no_alu32/usdt.test.o: CFLAGS:=3D$(subst O0,O2,$(CFLAGS)) +endif + # Define test_verifier test runner. # It is much simpler than test_maps/test_progs and sufficiently different = from # them (e.g., test.h is using completely pattern), that it's worth just diff --git a/tools/testing/selftests/bpf/prog_tests/usdt.c b/tools/testing/= selftests/bpf/prog_tests/usdt.c index 495d66414b57..86f354d25aef 100644 --- a/tools/testing/selftests/bpf/prog_tests/usdt.c +++ b/tools/testing/selftests/bpf/prog_tests/usdt.c @@ -14,10 +14,15 @@ static volatile int idx =3D 2; static volatile __u64 bla =3D 0xFEDCBA9876543210ULL; static volatile short nums[] =3D {-1, -2, -3, -4}; =20 -static volatile struct { - int x; - signed char y; -} t1 =3D { 1, -127 }; +/* + * TODO: At O2 optimization level, t1's USDT argument spec becomes -1@4+t= 1(%rip). + * Since libbpf doesn't support RIP addressing mode yet, this causes "unre= cognized register" errors. + * This test will be re-enabled once libbpf supports RIP addressing mode. + */ +// static volatile struct { +// int x; +// signed char y; +// } t1 =3D { 1, -127 }; =20 #define SEC(name) __attribute__((section(name), used)) =20 @@ -27,6 +32,7 @@ unsigned short test_usdt12_semaphore SEC(".probes"); =20 static void __always_inline trigger_func(int x) { long y =3D 42; + signed char t1 =3D -127; =20 if (test_usdt0_semaphore) STAP_PROBE(test, usdt0); @@ -36,7 +42,7 @@ static void __always_inline trigger_func(int x) { STAP_PROBE12(test, usdt12, x, x + 1, y, x + y, 5, y / 7, bla, &bla, -9, nums[x], - nums[idx], t1.y); + nums[idx], t1); } } =20 @@ -106,7 +112,7 @@ static void subtest_basic_usdt(void) ASSERT_EQ(bss->usdt12_args[8], -9, "usdt12_arg9"); ASSERT_EQ(bss->usdt12_args[9], nums[1], "usdt12_arg10"); ASSERT_EQ(bss->usdt12_args[10], nums[idx], "usdt12_arg11"); - ASSERT_EQ(bss->usdt12_args[11], t1.y, "usdt12_arg12"); + ASSERT_EQ(bss->usdt12_args[11], -127, "usdt12_arg12"); =20 int usdt12_expected_arg_sizes[12] =3D { 4, 4, 8, 8, 4, 8, 8, 8, 4, 2, 2, = 1 }; =20 --=20 2.43.0