netdev - [PATCH RFC bpf-next 3/4] selftests/bpf: Disable kprobe attach test with offset for CONFIG_X86_KERNEL

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Date:   Tue,  5 Jul 2022 21:03:07 +0200
From:   Jiri Olsa <jolsa@...nel.org>
To:     Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>
Cc:     netdev@...r.kernel.org, bpf@...r.kernel.org,
        Martin KaFai Lau <kafai@...com>,
        Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
        John Fastabend <john.fastabend@...il.com>,
        KP Singh <kpsingh@...omium.org>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Martynas Pumputis <m@...bda.lt>,
        Yutaro Hayakawa <yutaro.hayakawa@...valent.com>
Subject: [PATCH RFC bpf-next 3/4] selftests/bpf: Disable kprobe attach test with offset for CONFIG_X86_KERNEL_IBT

Attach like 'kprobe/bpf_fentry_test6+0x5' will fail to attach
when CONFIG_X86_KERNEL_IBT option is enabled because of the
endbr instruction at the function entry.

We would need to do manual attach with offset calculation based
on the CONFIG_X86_KERNEL_IBT option, which does not seem worth
the effort to me.

Disabling these test when CONFIG_X86_KERNEL_IBT is enabled.

Signed-off-by: Jiri Olsa <jolsa@...nel.org>
---
 .../bpf/prog_tests/get_func_ip_test.c         | 25 +++++++++++++++----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/get_func_ip_test.c b/tools/testing/selftests/bpf/prog_tests/get_func_ip_test.c
index 938dbd4d7c2f..cb0b78fb29df 100644
--- a/tools/testing/selftests/bpf/prog_tests/get_func_ip_test.c
+++ b/tools/testing/selftests/bpf/prog_tests/get_func_ip_test.c
@@ -2,6 +2,24 @@
 #include <test_progs.h>
 #include "get_func_ip_test.skel.h"
 
+/* assume IBT is enabled when kernel configs are not available */
+#ifdef HAVE_GENHDR
+# include "autoconf.h"
+#else
+#  define CONFIG_X86_KERNEL_IBT 1
+#endif
+
+/* test6 and test7 are x86_64 specific because of the instruction
+ * offset, disabling it for all other archs
+ *
+ * CONFIG_X86_KERNEL_IBT adds endbr instruction at function entry,
+ * so disabling test6 and test7, because the offset is hardcoded
+ * in program section
+ */
+#if !defined(__x86_64__) || defined(CONFIG_X86_KERNEL_IBT)
+#define DISABLE_OFFSET_ATTACH 1
+#endif
+
 void test_get_func_ip_test(void)
 {
 	struct get_func_ip_test *skel = NULL;
@@ -12,10 +30,7 @@ void test_get_func_ip_test(void)
 	if (!ASSERT_OK_PTR(skel, "get_func_ip_test__open"))
 		return;
 
-	/* test6 is x86_64 specifc because of the instruction
-	 * offset, disabling it for all other archs
-	 */
-#ifndef __x86_64__
+#if defined(DISABLE_OFFSET_ATTACH)
 	bpf_program__set_autoload(skel->progs.test6, false);
 	bpf_program__set_autoload(skel->progs.test7, false);
 #endif
@@ -43,7 +58,7 @@ void test_get_func_ip_test(void)
 	ASSERT_EQ(skel->bss->test3_result, 1, "test3_result");
 	ASSERT_EQ(skel->bss->test4_result, 1, "test4_result");
 	ASSERT_EQ(skel->bss->test5_result, 1, "test5_result");
-#ifdef __x86_64__
+#if !defined(DISABLE_OFFSET_ATTACH)
 	ASSERT_EQ(skel->bss->test6_result, 1, "test6_result");
 	ASSERT_EQ(skel->bss->test7_result, 1, "test7_result");
 #endif
-- 
2.35.3