From patchwork Tue May 21 10:48:16 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jiri Olsa X-Patchwork-Id: 13669263 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0250945BE4; Tue, 21 May 2024 10:48:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716288513; cv=none; b=h7xBarV0Ny8JR5mBmSo6GxjsbNFh/QosRJU/Un4XvGuRtQtgUHmNqNvxKykDGMcWsubmcSk40wEgIzvBXf6fqlR7HaUom0HfcWmoLcnol9j5EPAa6k9hjJJj9/E6gc52tQ8TXBEO5FyTZPhzD29G5ARsQvVR/q9rrlkYYRWwz0w= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716288513; c=relaxed/simple; bh=t6KrsjjS2cDjiQKKZKmCqoWmzszzaptCBic8EsD0Lcs=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=kemAbKBuGocxl2ZMDI2Luv5OHDHU3ccSjKj6ze8OEwsOoS6Ne40qq6fV89e/6OHE3n8hEdK7aTnMJBx3auYTBhgU+1djtStazv8NaXx+N3ymajvyowlsHdhhQpU5915jack9iXvtWAsMRKNzC47ImHaB/sLXDJws9/iOYzuX4h8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=EVgBONYJ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="EVgBONYJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6634AC2BD11; Tue, 21 May 2024 10:48:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1716288512; bh=t6KrsjjS2cDjiQKKZKmCqoWmzszzaptCBic8EsD0Lcs=; h=From:To:Cc:Subject:Date:From; b=EVgBONYJQggmaCPfwSOj4nXhhd9yInDgZzkSfx54efX438ljLBKovHogUSb9eQhYQ 9PrvB4Ha1eyFgG03mi9HH7wyYt+liD1Vypyr+z62CiKmxNSoymaExskdmWRxS7Ct/O kxSgqdYSFpM3ooEKpqdcRj8zwPRjI1Zu851tK8YT0mEk9Q48LqpHEcrYc4Ur5qa9TI wW+wP2R+9fp2TqWOwL5+8xC5HSq6gZx+xqWnpx4bfG1cw7g2mAcAYzCTcPZ1uJ/VVB FCMNjdk0b5wwUDCDyu9MbGralMKiTFbrnkDspLaSqf2+iZvWNow4UpGd8PVVl5M539 95G5aXdqmz0IQ== From: Jiri Olsa To: Steven Rostedt , Masami Hiramatsu , Oleg Nesterov , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-api@vger.kernel.org, linux-man@vger.kernel.org, x86@kernel.org, bpf@vger.kernel.org, Song Liu , Yonghong Song , John Fastabend , Peter Zijlstra , Thomas Gleixner , "Borislav Petkov (AMD)" , Ingo Molnar , Andy Lutomirski , "Edgecombe, Rick P" , Deepak Gupta Subject: [PATCHv6 bpf-next 0/9] uprobe: uretprobe speed up Date: Tue, 21 May 2024 12:48:16 +0200 Message-ID: <20240521104825.1060966-1-jolsa@kernel.org> X-Mailer: git-send-email 2.45.0 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 hi, as part of the effort on speeding up the uprobes [0] coming with return uprobe optimization by using syscall instead of the trap on the uretprobe trampoline. The speed up depends on instruction type that uprobe is installed and depends on specific HW type, please check patch 1 for details. Patches 1-8 are based on bpf-next/master, but patch 2 and 3 are apply-able on linux-trace.git tree probes/for-next branch. Patch 9 is based on man-pages master. v6 changes: - separate shadow stack fix for current uretprobe in patch 1 - skip shadow stack test when uprobe is not compiled int [Masami] - fix retprobe with the shadow stack, using iret return when shadow stack is detected - I kept the acks on patch 3, because the shadow stack change is minimal and the original code is almost untouched - added shadow stack bpf selftest - rebased man page Also available at: https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git uretprobe_syscall thanks, jirka Notes to check list items in Documentation/process/adding-syscalls.rst: - System Call Alternatives New syscall seems like the best way in here, because we need just to quickly enter kernel with no extra arguments processing, which we'd need to do if we decided to use another syscall. - Designing the API: Planning for Extension The uretprobe syscall is very specific and most likely won't be extended in the future. At the moment it does not take any arguments and even if it does in future, it's allowed to be called only from trampoline prepared by kernel, so there'll be no broken user. - Designing the API: Other Considerations N/A because uretprobe syscall does not return reference to kernel object. - Proposing the API Wiring up of the uretprobe system call is in separate change, selftests and man page changes are part of the patchset. - Generic System Call Implementation There's no CONFIG option for the new functionality because it keeps the same behaviour from the user POV. - x86 System Call Implementation It's 64-bit syscall only. - Compatibility System Calls (Generic) N/A uretprobe syscall has no arguments and is not supported for compat processes. - Compatibility System Calls (x86) N/A uretprobe syscall is not supported for compat processes. - System Calls Returning Elsewhere N/A. - Other Details N/A. - Testing Adding new bpf selftests and ran ltp on top of this change. - Man Page Attached. - Do not call System Calls in the Kernel N/A. [0] https://lore.kernel.org/bpf/ZeCXHKJ--iYYbmLj@krava/ --- Jiri Olsa (8): x86/shstk: Make return uprobe work with shadow stack uprobe: Wire up uretprobe system call uprobe: Add uretprobe syscall to speed up return probe selftests/x86: Add return uprobe shadow stack test selftests/bpf: Add uretprobe syscall test for regs integrity selftests/bpf: Add uretprobe syscall test for regs changes selftests/bpf: Add uretprobe syscall call from user space test selftests/bpf: Add uretprobe shadow stack test arch/x86/entry/syscalls/syscall_64.tbl | 1 + arch/x86/include/asm/shstk.h | 4 + arch/x86/kernel/shstk.c | 16 ++++ arch/x86/kernel/uprobes.c | 124 ++++++++++++++++++++++++++++- include/linux/syscalls.h | 2 + include/linux/uprobes.h | 3 + include/uapi/asm-generic/unistd.h | 5 +- kernel/events/uprobes.c | 24 ++++-- kernel/sys_ni.c | 2 + tools/include/linux/compiler.h | 4 + tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c | 123 ++++++++++++++++++++++++++++- tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c | 385 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ tools/testing/selftests/bpf/progs/uprobe_syscall.c | 15 ++++ tools/testing/selftests/bpf/progs/uprobe_syscall_executed.c | 17 ++++ tools/testing/selftests/x86/test_shadow_stack.c | 145 ++++++++++++++++++++++++++++++++++ 15 files changed, 860 insertions(+), 10 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c create mode 100644 tools/testing/selftests/bpf/progs/uprobe_syscall.c create mode 100644 tools/testing/selftests/bpf/progs/uprobe_syscall_executed.c Jiri Olsa (1): man2: Add uretprobe syscall page man/man2/uretprobe.2 | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) create mode 100644 man/man2/uretprobe.2