From patchwork Wed Feb 14 17:18:29 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Benjamin Tissoires X-Patchwork-Id: 773524 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 8E1126A002; Wed, 14 Feb 2024 17:19:00 +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=1707931140; cv=none; b=csKW+ARMcoAXc+oCedrNqXyhvQ7Ca2iy6jWHXGExPHG1s7o+qeZVe2NmepQ2c/fpJv0O5pxbfwpKWVLHmaxi7nKgsEDfcbCvkKO6cYtQxUPJ6li729CU05cUhuGhrP86P9S/C9mgrFFWXwsOiS+uSCsg5O3KEz7l+bsDnlc2RuA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707931140; c=relaxed/simple; bh=l4jPudJnwEihlvPPrQPrGvmbzUPliLgvg6nSOC6YQe0=; h=From:Subject:Date:Message-Id:MIME-Version:Content-Type:To:Cc; b=jROi+tTVeAd1zRaWhbBEJBxYv/btedw4zs9Z+z184UhiKxj5MxM1a9r+uKq3UxHbvGYAMMhj+qyA5BAEr+uY7bJHCD7LNLmFAw7nu1LpF2sYZ9r0XA979eNoKLDVVkyM6dSNmj69mexwp7Huk4Rl4kaH5NYNtHOUYHTdY5EeKvQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=hx0HSkx1; 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="hx0HSkx1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 19A79C433F1; Wed, 14 Feb 2024 17:18:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1707931140; bh=l4jPudJnwEihlvPPrQPrGvmbzUPliLgvg6nSOC6YQe0=; h=From:Subject:Date:To:Cc:From; b=hx0HSkx1O1vfzja/tcyeZbnl6f8DBH6HsvtBo3ONzOetV9It+308217dhB44DWKtj 185FjCFdmK4w50Q/Fodsi68L4Fzq2BbLu8VCWU/WBn5Wj62Qw9ytHq53Xa8s3BZS0I +NVewubwnkk+oH7tKIog+zZDjKF2k0lSfburOYaN4ClYy9K0umRFBp7WjCkbze9CXU L76vSRCcAVrO1RjrasfJd3lJdqtd+iIL/36BM4xsNB6KbYTqezPlesT6IV6YZpUN8z KJAeRmL6EN9ZeCFbkeIGFW86Jundzi80P3xleNLsmhR4lCaWaLrcODAwze5HYhzffX KhqgKoNs1do4w== From: Benjamin Tissoires Subject: [PATCH RFC bpf-next v2 00/10] allow HID-BPF to do device IOs Date: Wed, 14 Feb 2024 18:18:29 +0100 Message-Id: <20240214-hid-bpf-sleepable-v2-0-5756b054724d@kernel.org> Precedence: bulk X-Mailing-List: linux-input@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-B4-Tracking: v=1; b=H4sIAOX1zGUC/22NzQqDMBCEX0X23C1J0FJ7Kgh9gF6Lh/ysulSiJ CIW8d0bpccev2HmmxUiBaYIt2yFQDNHHnwCdcrAdtq3hOwSgxIqF0oU2LFDMzYYe6JRm57QCqk uonGltDmk3Rio4eVwvuD5qPZsX3haJqgTdBynIXyOz1ketZ++/KOfJQrMrb2WhSm0M+7+puCpP w+hhXrbti9T1WMxxAAAAA== To: Alexei Starovoitov , Daniel Borkmann , John Fastabend , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Jiri Kosina , Benjamin Tissoires , Jonathan Corbet , Shuah Khan Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-input@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, Benjamin Tissoires X-Mailer: b4 0.12.4 X-Developer-Signature: v=1; a=ed25519-sha256; t=1707931135; l=4831; i=bentiss@kernel.org; s=20230215; h=from:subject:message-id; bh=l4jPudJnwEihlvPPrQPrGvmbzUPliLgvg6nSOC6YQe0=; b=hDh4ILe9/u3jIkDCjyvSuvoJvM06QQCqlwjQWjY8/CM4pM6y+4TuGu4kVCvcawjJhIlrsZ1Ea vihnZbrsM5AAHQJuhsj1rOE9w9lWKerP8iZ7fltXljCYW50rWrsGdZ8 X-Developer-Key: i=bentiss@kernel.org; a=ed25519; pk=7D1DyAVh6ajCkuUTudt/chMuXWIJHlv2qCsRkIizvFw= [Still a RFC: there are a lot of FIXMEs in the code, and calling the sleepable timer cb actually crashes.] [Also using bpf-next as the base tree as there will be conflicting changes otherwise] This is crashing, and I have a few questions in the code (look for all of the FIXMEs), so sending this now before I become insane :) For reference, the use cases I have in mind: --- Basically, I need to be able to defer a HID-BPF program for the following reasons (from the aforementioned patch): 1. defer an event: Sometimes we receive an out of proximity event, but the device can not be trusted enough, and we need to ensure that we won't receive another one in the following n milliseconds. So we need to wait those n milliseconds, and eventually re-inject that event in the stack. 2. inject new events in reaction to one given event: We might want to transform one given event into several. This is the case for macro keys where a single key press is supposed to send a sequence of key presses. But this could also be used to patch a faulty behavior, if a device forgets to send a release event. 3. communicate with the device in reaction to one event: We might want to communicate back to the device after a given event. For example a device might send us an event saying that it came back from sleeping state and needs to be re-initialized. Currently we can achieve that by keeping a userspace program around, raise a bpf event, and let that userspace program inject the events and commands. However, we are just keeping that program alive as a daemon for just scheduling commands. There is no logic in it, so it doesn't really justify an actual userspace wakeup. So a kernel workqueue seems simpler to handle. The other part I'm not sure is whether we can say that BPF maps of type queue/stack can be used in sleepable context. I don't see any warning when running the test programs, but that's probably not a guarantee I'm doing the things properly :) Cheers, Benjamin To: Alexei Starovoitov To: Daniel Borkmann To: John Fastabend To: Andrii Nakryiko To: Martin KaFai Lau To: Eduard Zingerman To: Song Liu To: Yonghong Song To: KP Singh To: Stanislav Fomichev To: Hao Luo To: Jiri Olsa To: Jiri Kosina To: Benjamin Tissoires To: Jonathan Corbet To: Shuah Khan Cc: Cc: Cc: Cc: Cc: Signed-off-by: Benjamin Tissoires --- Changes in v2: - make use of bpf_timer (and dropped the custom HID handling) - implemented bpf_timer_set_sleepable_cb as a kfunc - still not implemented global subprogs - no sleepable bpf_timer selftests yet - Link to v1: https://lore.kernel.org/r/20240209-hid-bpf-sleepable-v1-0-4cc895b5adbd@kernel.org --- Benjamin Tissoires (10): bpf/verifier: introduce in_sleepable() helper bpf/helpers: introduce sleepable timers bpf/verifier: allow more maps in sleepable bpf programs HID: bpf/dispatch: regroup kfuncs definitions HID: bpf: export hid_hw_output_report as a BPF kfunc selftests/hid: Add test for hid_bpf_hw_output_report HID: bpf: allow to inject HID event from BPF selftests/hid: add tests for hid_bpf_input_report HID: bpf: allow to use bpf_timer_set_sleepable_cb() in tracing callbacks. selftests/hid: add test for bpf_timer Documentation/hid/hid-bpf.rst | 2 +- drivers/hid/bpf/hid_bpf_dispatch.c | 232 ++++++++++++++------- drivers/hid/hid-core.c | 2 + include/linux/bpf_verifier.h | 2 + include/linux/hid_bpf.h | 3 + include/uapi/linux/bpf.h | 12 ++ kernel/bpf/helpers.c | 105 +++++++++- kernel/bpf/verifier.c | 91 +++++++- tools/testing/selftests/hid/hid_bpf.c | 195 ++++++++++++++++- tools/testing/selftests/hid/progs/hid.c | 198 ++++++++++++++++++ .../testing/selftests/hid/progs/hid_bpf_helpers.h | 8 + 11 files changed, 756 insertions(+), 94 deletions(-) --- base-commit: 4f7a05917237b006ceae760507b3d15305769ade change-id: 20240205-hid-bpf-sleepable-c01260fd91c4 Best regards,