linux-kernel - [PATCHv3 bpf-next 1/5] selftests/bpf: Emit nop,nop5 instructions combo for x86

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20260211084858.750950-2-jolsa@kernel.org>
Date: Wed, 11 Feb 2026 09:48:54 +0100
From: Jiri Olsa <jolsa@...nel.org>
To: Andrii Nakryiko <andrii@...nel.org>
Cc: bpf@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Song Liu <songliubraving@...com>,
	Yonghong Song <yhs@...com>,
	John Fastabend <john.fastabend@...il.com>
Subject: [PATCHv3 bpf-next 1/5] selftests/bpf: Emit nop,nop5 instructions combo for x86_64 arch

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@...nel.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