From: Jiri Olsa <jolsa@kernel.org>
To: Andrii Nakryiko <andrii@kernel.org>
Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
John Fastabend <john.fastabend@gmail.com>
Subject: [PATCHv4 bpf-next 3/5] selftests/bpf: Emit nop,nop5 instructions combo for x86_64 arch
Date: Fri, 20 Feb 2026 11:42:18 +0100 [thread overview]
Message-ID: <20260220104220.634154-4-jolsa@kernel.org> (raw)
In-Reply-To: <20260220104220.634154-1-jolsa@kernel.org>
Syncing latest usdt.h change [1].
Now that we have nop5 optimization support in kernel, let's emit
nop,nop5 for usdt probe. We leave it up to the library to use
desirable nop instruction.
[1] https://github.com/libbpf/usdt/commit/c9865d158984fb2b73e3cbbdcdfb4f583ad36a73
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
tools/testing/selftests/bpf/usdt.h | 2 ++
1 file changed, 2 insertions(+)
diff --git a/tools/testing/selftests/bpf/usdt.h b/tools/testing/selftests/bpf/usdt.h
index 549d1f774810..c71e21df38b3 100644
--- a/tools/testing/selftests/bpf/usdt.h
+++ b/tools/testing/selftests/bpf/usdt.h
@@ -312,6 +312,8 @@ struct usdt_sema { volatile unsigned short active; };
#ifndef USDT_NOP
#if defined(__ia64__) || defined(__s390__) || defined(__s390x__)
#define USDT_NOP nop 0
+#elif defined(__x86_64__)
+#define USDT_NOP .byte 0x90, 0x0f, 0x1f, 0x44, 0x00, 0x0 /* nop, nop5 */
#else
#define USDT_NOP nop
#endif
--
2.53.0
next prev parent reply other threads:[~2026-02-20 10:43 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-20 10:42 [PATCHv4 bpf-next 0/5] libbpf: Make optimized uprobes backward compatible Jiri Olsa
2026-02-20 10:42 ` [PATCHv4 bpf-next 1/5] libbpf: Add uprobe syscall feature detection Jiri Olsa
2026-02-20 10:42 ` [PATCHv4 bpf-next 2/5] libbpf: Add support to detect nop,nop5 instructions combo for usdt probe Jiri Olsa
2026-02-20 11:24 ` bot+bpf-ci
2026-02-21 12:00 ` David Laight
2026-02-22 14:32 ` Jiri Olsa
2026-02-20 10:42 ` Jiri Olsa [this message]
2026-02-20 10:42 ` [PATCHv4 bpf-next 4/5] selftests/bpf: Add test for checking correct nop of optimized usdt Jiri Olsa
2026-02-20 10:42 ` [PATCHv4 bpf-next 5/5] selftests/bpf: Add usdt trigger bench Jiri Olsa
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