From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 7A8E941F5F5; Sun, 6 Sep 2026 10:07:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788689243; cv=none; b=SSJo+/W6UYhXSrW2ArzinbbfW4IBUylzSVGkHWdjiwn/7W4Enzggbjpfs0hUeDbs3bPJ9d5jZME+nxWmjs1b20yi0y/ohxaxo8jns2w8kQ4CKZHuEp/odR+OHIBNkHBYOoRXqqrNeYVcvubDZWdFlv+GNHehYHenCjxmN87h/jM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788689243; c=relaxed/simple; bh=Z1zT/+qmdnYlo6v6PyvGTRruroGKs4FxS/7jYNNL1h8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=P8JI+Ql4vVunlX8dwVK94d8ndibamEf07xZJzHSbk+r5dvg631hgA9dhyK+XbgcAi9l2fKdLS0OZmVB/+Md5skyPIdKJqJcXWofnCY5s4oqT5d2QhYBdnNhug59hnJsuplVnL+rVX9B7jMbOG0xfMw9Y5E0P58HXaykNutGkPOI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=KyN0M5Vy; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="KyN0M5Vy" Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 1E1EE1713; Sun, 6 Sep 2026 03:07:14 -0700 (PDT) Received: from pluto (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 8DD1A3FA21; Sun, 6 Sep 2026 03:07:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1788689237; bh=Z1zT/+qmdnYlo6v6PyvGTRruroGKs4FxS/7jYNNL1h8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KyN0M5VywQJ+IsrLTyzz7ETU5ITGGJqzNK/ijn+6wBYVFeA6UT1UL4JY1Emd0HN7c 3NYPs9O2k8bIujhmaCBm1PjeZR52tFUJaczNPv6AjyHHTINB3BOtqdZqOkXmI6kM+L 0GV9hpu94GHhQmvDlGaKug30DNZNg3i5YYKSOIIo= From: Cristian Marussi To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, arm-scmi@vger.kernel.org, linux-doc@vger.kernel.org Cc: sudeep.holla@kernel.org, james.quinlan@broadcom.com, f.fainelli@gmail.com, vincent.guittot@linaro.org, etienne.carriere@st.com, peng.fan@oss.nxp.com, michal.simek@amd.com, d-gole@ti.com, jic23@kernel.org, elif.topuz@arm.com, lukasz.luba@arm.com, philip.radford@arm.com, david@kernel.org, souvik.chakravarty@arm.com, leitao@kernel.org, kas@kernel.org, puranjay@kernel.org, usama.arif@linux.dev, kernel-team@meta.com, Cristian Marussi , Jonathan Cameron Subject: [PATCH v11 02/25] firmware: arm_scmi: Allow registration of unknown-size events/reports Date: Sun, 6 Sep 2026 11:06:00 +0100 Message-ID: <20260906100623.3488327-3-cristian.marussi@arm.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260906100623.3488327-1-cristian.marussi@arm.com> References: <20260906100623.3488327-1-cristian.marussi@arm.com> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Allow protocols to register events with build-time unknown sizes: such events can be declared zero-sized and let the core SCMI stack perform the needed safe-net boundary checks based on the configured transport size. Reviewed-by: Jonathan Cameron Signed-off-by: Cristian Marussi --- v10 --> v11 - account for ktime_t field when checking boundary v2 --> v3 - split out of previous patch on protocol notifier - use max() instead of max_t() --- drivers/firmware/arm_scmi/notify.c | 25 ++++++++++++++++++++----- drivers/firmware/arm_scmi/notify.h | 8 ++++++-- 2 files changed, 26 insertions(+), 7 deletions(-) diff --git a/drivers/firmware/arm_scmi/notify.c b/drivers/firmware/arm_scmi/notify.c index fb60fb07c0ed..3264e1062700 100644 --- a/drivers/firmware/arm_scmi/notify.c +++ b/drivers/firmware/arm_scmi/notify.c @@ -595,7 +595,13 @@ int scmi_notify(const struct scmi_handle *handle, u8 proto_id, u8 evt_id, if (!r_evt) return -EINVAL; - if (len > r_evt->evt->max_payld_sz) { + /* + * Events with a zero max_payld_sz are sized to be of the maximum + * size allowed by the transport: no need to be size-checked here + * since the transport layer would have already dropped such + * over-sized messages. + */ + if (r_evt->evt->max_payld_sz && len > r_evt->evt->max_payld_sz) { dev_err(handle->dev, "discard badly sized message\n"); return -EINVAL; } @@ -752,7 +758,7 @@ int scmi_register_protocol_events(const struct scmi_handle *handle, u8 proto_id, const struct scmi_protocol_handle *ph, const struct scmi_protocol_events *ee) { - int i; + int i, max_msg_sz, max_report_sz; unsigned int num_sources; size_t payld_sz = 0; struct scmi_registered_events_desc *pd; @@ -767,6 +773,9 @@ int scmi_register_protocol_events(const struct scmi_handle *handle, u8 proto_id, if (!ni) return -ENOMEM; + max_msg_sz = ph->hops->get_max_msg_size(ph); + max_report_sz = max_msg_sz + sizeof(ktime_t); + /* num_sources cannot be <= 0 */ if (ee->num_sources) { num_sources = ee->num_sources; @@ -779,8 +788,13 @@ int scmi_register_protocol_events(const struct scmi_handle *handle, u8 proto_id, } evt = ee->evts; - for (i = 0; i < ee->num_events; i++) - payld_sz = max_t(size_t, payld_sz, evt[i].max_payld_sz); + for (i = 0; i < ee->num_events; i++) { + if (evt[i].max_payld_sz == 0) { + payld_sz = max_msg_sz; + break; + } + payld_sz = max(payld_sz, evt[i].max_payld_sz); + } payld_sz += sizeof(struct scmi_event_header); pd = scmi_allocate_registered_events_desc(ni, proto_id, ee->queue_sz, @@ -807,7 +821,8 @@ int scmi_register_protocol_events(const struct scmi_handle *handle, u8 proto_id, mutex_init(&r_evt->sources_mtx); r_evt->report = devm_kzalloc(ni->handle->dev, - evt->max_report_sz, GFP_KERNEL); + evt->max_report_sz ?: max_report_sz, + GFP_KERNEL); if (!r_evt->report) return -ENOMEM; diff --git a/drivers/firmware/arm_scmi/notify.h b/drivers/firmware/arm_scmi/notify.h index f18f98c5ab3b..c2eb4844c7db 100644 --- a/drivers/firmware/arm_scmi/notify.h +++ b/drivers/firmware/arm_scmi/notify.h @@ -18,8 +18,12 @@ /** * struct scmi_event - Describes an event to be supported * @id: Event ID - * @max_payld_sz: Max possible size for the payload of a notification message - * @max_report_sz: Max possible size for the report of a notification message + * @max_payld_sz: Max possible size for the payload of a notification message. + * Set to zero to use the maximum payload size allowed by the + * transport. + * @max_report_sz: Max possible size for the report of a notification message. + * Set to zero to use the maximum payload size allowed by the + * transport plus the additional ktime_t timestamp. * * Each SCMI protocol, during its initialization phase, can describe the events * it wishes to support in a few struct scmi_event and pass them to the core -- 2.54.0