From nobody Sun Feb 8 09:27:53 2026 Received: from out30-101.freemail.mail.aliyun.com (out30-101.freemail.mail.aliyun.com [115.124.30.101]) (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 F12221D516C; Sat, 25 Oct 2025 11:42:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.101 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761392544; cv=none; b=e0JDq5i9qE5HUpLAYqsBk2TktptsQ+8ic8pJSAp3RfzIuQ4ISkMNFTYOYxfW2P+LCr3yqf73K7x1yP/Ul1tFSm/AIRQwmrIyQPNfGh77l1nwGlgE1XpJ8yhxCbT+oIATw/DWvbT+oRqZAES7twQHP5rkuJWmgZHKJ0RhVA3ceI4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761392544; c=relaxed/simple; bh=4GpavlZCK7jfW+tbgBCh97zrQasfjN1Irb4roaVDKN4=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=O23h6/pIeGzqdinrqqZCpwGrJUtpmJALh4KXvloXolBDUekhLPN7mtaF5yDFSvKkVjbCeP8J1zHLy4wqLsahx/zyJ0fs5ivgIJ3zfnSstQ9QG1IoJv1rwChQZD25IWvG9u8ZtoKLoN6/Qrn1Lj422sOoDRcnIa1v27n2HmVmnkc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=Au+GUjnI; arc=none smtp.client-ip=115.124.30.101 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="Au+GUjnI" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1761392528; h=From:To:Subject:Date:Message-Id:MIME-Version:Content-Type; bh=daBDsIEoo7d0DXzD96pe4JGjDFJicmWft6qR8RVDeNU=; b=Au+GUjnIhRk4Nbrko7T2QCps8MCyvFwrtpNeyQYnmUNbq5q8muwGRDzgKEdnJBnj1y9piOUkA38B3Z1V5t5Cl3KeWN80m5Y6oIFZFsxMePQU2i2nNdrrBbIFzCY7VU2q6KrsbcTdruNq7if9jxibHAm2pVz+YUEuV3Yp0VvDWG0= Received: from localhost.localdomain(mailfrom:xueshuai@linux.alibaba.com fp:SMTPD_---0WqwoUgY_1761392525 cluster:ay36) by smtp.aliyun-inc.com; Sat, 25 Oct 2025 19:42:06 +0800 From: Shuai Xue To: rostedt@goodmis.org, lukas@wunner.de, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-edac@vger.kernel.org, linux-trace-kernel@vger.kernel.org, helgaas@kernel.org, ilpo.jarvinen@linux.intel.com, mattc@purestorage.com, Jonathan.Cameron@huawei.com Cc: bhelgaas@google.com, tony.luck@intel.com, bp@alien8.de, xueshuai@linux.alibaba.com, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, oleg@redhat.com, naveen@kernel.org, davem@davemloft.net, anil.s.keshavamurthy@intel.com, mark.rutland@arm.com, peterz@infradead.org, tianruidong@linux.alibaba.com Subject: [PATCH v13 1/3] PCI: trace: Add a generic RAS tracepoint for hotplug event Date: Sat, 25 Oct 2025 19:41:56 +0800 Message-Id: <20251025114158.71714-2-xueshuai@linux.alibaba.com> X-Mailer: git-send-email 2.39.5 (Apple Git-154) In-Reply-To: <20251025114158.71714-1-xueshuai@linux.alibaba.com> References: <20251025114158.71714-1-xueshuai@linux.alibaba.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Hotplug events are critical indicators for analyzing hardware health, and surprise link downs can significantly impact system performance and reliability. Define a new TRACING_SYSTEM named "pci", add a generic RAS tracepoint for hotplug event to help health checks. Add enum pci_hotplug_event in include/uapi/linux/pci.h so applications like rasdaemon can register tracepoint event handlers for it. The following output is generated when a device is hotplugged: $ echo 1 > /sys/kernel/debug/tracing/events/pci/pci_hp_event/enable $ cat /sys/kernel/debug/tracing/trace_pipe irq/51-pciehp-88 [001] ..... 1311.177459: pci_hp_event: 0000:00:02= .0 slot:10, event:CARD_PRESENT irq/51-pciehp-88 [001] ..... 1311.177566: pci_hp_event: 0000:00:02= .0 slot:10, event:LINK_UP Suggested-by: Lukas Wunner Reviewed-by: Lukas Wunner Reviewed-by: Jonathan Cameron Reviewed-by: "Steven Rostedt (Google)" # for trace ev= ent Reviewed-by: Ilpo J=C3=A4rvinen Signed-off-by: Shuai Xue --- drivers/pci/Makefile | 3 ++ drivers/pci/hotplug/pciehp_ctrl.c | 31 ++++++++++--- drivers/pci/trace.c | 11 +++++ include/trace/events/pci.h | 72 +++++++++++++++++++++++++++++++ include/uapi/linux/pci.h | 7 +++ 5 files changed, 118 insertions(+), 6 deletions(-) create mode 100644 drivers/pci/trace.c create mode 100644 include/trace/events/pci.h diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile index 67647f1880fb..58a4e4ea76b0 100644 --- a/drivers/pci/Makefile +++ b/drivers/pci/Makefile @@ -45,3 +45,6 @@ obj-y +=3D controller/ obj-y +=3D switch/ =20 subdir-ccflags-$(CONFIG_PCI_DEBUG) :=3D -DDEBUG + +CFLAGS_trace.o :=3D -I$(src) +obj-$(CONFIG_TRACING) +=3D trace.o diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp= _ctrl.c index bcc938d4420f..7805f697a02c 100644 --- a/drivers/pci/hotplug/pciehp_ctrl.c +++ b/drivers/pci/hotplug/pciehp_ctrl.c @@ -19,6 +19,7 @@ #include #include #include +#include =20 #include "../pci.h" #include "pciehp.h" @@ -244,12 +245,20 @@ void pciehp_handle_presence_or_link_change(struct con= troller *ctrl, u32 events) case ON_STATE: ctrl->state =3D POWEROFF_STATE; mutex_unlock(&ctrl->state_lock); - if (events & PCI_EXP_SLTSTA_DLLSC) + if (events & PCI_EXP_SLTSTA_DLLSC) { ctrl_info(ctrl, "Slot(%s): Link Down\n", slot_name(ctrl)); - if (events & PCI_EXP_SLTSTA_PDC) + trace_pci_hp_event(pci_name(ctrl->pcie->port), + slot_name(ctrl), + PCI_HOTPLUG_LINK_DOWN); + } + if (events & PCI_EXP_SLTSTA_PDC) { ctrl_info(ctrl, "Slot(%s): Card not present\n", slot_name(ctrl)); + trace_pci_hp_event(pci_name(ctrl->pcie->port), + slot_name(ctrl), + PCI_HOTPLUG_CARD_NOT_PRESENT); + } pciehp_disable_slot(ctrl, SURPRISE_REMOVAL); break; default: @@ -269,6 +278,9 @@ void pciehp_handle_presence_or_link_change(struct contr= oller *ctrl, u32 events) INDICATOR_NOOP); ctrl_info(ctrl, "Slot(%s): Card not present\n", slot_name(ctrl)); + trace_pci_hp_event(pci_name(ctrl->pcie->port), + slot_name(ctrl), + PCI_HOTPLUG_CARD_NOT_PRESENT); } mutex_unlock(&ctrl->state_lock); return; @@ -281,12 +293,19 @@ void pciehp_handle_presence_or_link_change(struct con= troller *ctrl, u32 events) case OFF_STATE: ctrl->state =3D POWERON_STATE; mutex_unlock(&ctrl->state_lock); - if (present) + if (present) { ctrl_info(ctrl, "Slot(%s): Card present\n", slot_name(ctrl)); - if (link_active) - ctrl_info(ctrl, "Slot(%s): Link Up\n", - slot_name(ctrl)); + trace_pci_hp_event(pci_name(ctrl->pcie->port), + slot_name(ctrl), + PCI_HOTPLUG_CARD_PRESENT); + } + if (link_active) { + ctrl_info(ctrl, "Slot(%s): Link Up\n", slot_name(ctrl)); + trace_pci_hp_event(pci_name(ctrl->pcie->port), + slot_name(ctrl), + PCI_HOTPLUG_LINK_UP); + } ctrl->request_result =3D pciehp_enable_slot(ctrl); break; default: diff --git a/drivers/pci/trace.c b/drivers/pci/trace.c new file mode 100644 index 000000000000..cf11abca8602 --- /dev/null +++ b/drivers/pci/trace.c @@ -0,0 +1,11 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Tracepoints for PCI system + * + * Copyright (C) 2025 Alibaba Corporation + */ + +#include + +#define CREATE_TRACE_POINTS +#include diff --git a/include/trace/events/pci.h b/include/trace/events/pci.h new file mode 100644 index 000000000000..39e512a167ee --- /dev/null +++ b/include/trace/events/pci.h @@ -0,0 +1,72 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM pci + +#if !defined(_TRACE_HW_EVENT_PCI_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_HW_EVENT_PCI_H + +#include + +#define PCI_HOTPLUG_EVENT \ + EM(PCI_HOTPLUG_LINK_UP, "LINK_UP") \ + EM(PCI_HOTPLUG_LINK_DOWN, "LINK_DOWN") \ + EM(PCI_HOTPLUG_CARD_PRESENT, "CARD_PRESENT") \ + EMe(PCI_HOTPLUG_CARD_NOT_PRESENT, "CARD_NOT_PRESENT") + +/* Enums require being exported to userspace, for user tool parsing */ +#undef EM +#undef EMe +#define EM(a, b) TRACE_DEFINE_ENUM(a); +#define EMe(a, b) TRACE_DEFINE_ENUM(a); + +PCI_HOTPLUG_EVENT + +/* + * Now redefine the EM() and EMe() macros to map the enums to the strings + * that will be printed in the output. + */ +#undef EM +#undef EMe +#define EM(a, b) {a, b}, +#define EMe(a, b) {a, b} + +/* + * Note: For generic PCI hotplug events, we pass already-resolved strings + * (port_name, slot) instead of driver-specific structures like 'struct + * controller'. This is because different PCI hotplug drivers (pciehp, cp= qphp, + * ibmphp, shpchp) define their own versions of 'struct controller' with + * different fields and helper functions. Using driver-specific structures= would + * make the tracepoint interface non-generic and cause compatibility issues + * across different drivers. + */ +TRACE_EVENT(pci_hp_event, + + TP_PROTO(const char *port_name, + const char *slot, + const int event), + + TP_ARGS(port_name, slot, event), + + TP_STRUCT__entry( + __string( port_name, port_name ) + __string( slot, slot ) + __field( int, event ) + ), + + TP_fast_assign( + __assign_str(port_name); + __assign_str(slot); + __entry->event =3D event; + ), + + TP_printk("%s slot:%s, event:%s\n", + __get_str(port_name), + __get_str(slot), + __print_symbolic(__entry->event, PCI_HOTPLUG_EVENT) + ) +); + +#endif /* _TRACE_HW_EVENT_PCI_H */ + +/* This part must be outside protection */ +#include diff --git a/include/uapi/linux/pci.h b/include/uapi/linux/pci.h index a769eefc5139..4f150028965d 100644 --- a/include/uapi/linux/pci.h +++ b/include/uapi/linux/pci.h @@ -39,4 +39,11 @@ #define PCIIOC_MMAP_IS_MEM (PCIIOC_BASE | 0x02) /* Set mmap state to MEM s= pace. */ #define PCIIOC_WRITE_COMBINE (PCIIOC_BASE | 0x03) /* Enable/disable write-= combining. */ =20 +enum pci_hotplug_event { + PCI_HOTPLUG_LINK_UP, + PCI_HOTPLUG_LINK_DOWN, + PCI_HOTPLUG_CARD_PRESENT, + PCI_HOTPLUG_CARD_NOT_PRESENT, +}; + #endif /* _UAPILINUX_PCI_H */ --=20 2.39.3 From nobody Sun Feb 8 09:27:53 2026 Received: from out30-133.freemail.mail.aliyun.com (out30-133.freemail.mail.aliyun.com [115.124.30.133]) (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 D33472F83B8; Sat, 25 Oct 2025 11:42:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.133 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761392540; cv=none; b=dIHFZ+w/O6PpNPciHHiyJWMg493o67b728WZaVCYyEp+6onz1C59nKvbQ8iY2No42F748lrzye5Ds9pyJK3+A7HxAXY+sFhFUlguPL/ZgSV1mmimFXe4JiwwPXkDhVAMXTljy1jmJzafMmeet7GCwlHg2ZPjWPIBz/uO5hR/KkU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761392540; c=relaxed/simple; bh=OUh/XG151vsZreFH20lIvtumt84ynAEZS96GcNa0wxs=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=CRNRH/rOV+2vrSxeIMiuMkUb/7CNVJ9pCWYm+XOu5OH3fcjEdL9fr/EYGuufEYnFJX9c2wnIKZ3yY+ZpHTI/6x/zrgf0nAeC73DiXu4aqJra3NbuJU4IdzqhTFfQkLn7uWSqWmgG9TLj4n/eQyF/AUZn58G/358tQ80bJkNiAgM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=eqFCeupG; arc=none smtp.client-ip=115.124.30.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="eqFCeupG" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1761392529; h=From:To:Subject:Date:Message-Id:MIME-Version:Content-Type; bh=ZXis57oCSpBFB4a8y0ISQ5Oi5GcKyDv+DrwQmN1TBwo=; b=eqFCeupG0uCBMxxx6AMXnMvuYBnYBVbP7suO5hcLJCf5SD8fSN8mf56rJV1Zt988PJ++HhIq8hzYX4ghy45ZTJVuy7a0nfrYol8k0eiDkvlbMbDhS9O/tFWQrzN7OSPsXgT6fDbC0ufYSaidWFUqB5cEc0vbB7cT6oJv3X3/OVM= Received: from localhost.localdomain(mailfrom:xueshuai@linux.alibaba.com fp:SMTPD_---0WqwoUh2_1761392526 cluster:ay36) by smtp.aliyun-inc.com; Sat, 25 Oct 2025 19:42:07 +0800 From: Shuai Xue To: rostedt@goodmis.org, lukas@wunner.de, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-edac@vger.kernel.org, linux-trace-kernel@vger.kernel.org, helgaas@kernel.org, ilpo.jarvinen@linux.intel.com, mattc@purestorage.com, Jonathan.Cameron@huawei.com Cc: bhelgaas@google.com, tony.luck@intel.com, bp@alien8.de, xueshuai@linux.alibaba.com, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, oleg@redhat.com, naveen@kernel.org, davem@davemloft.net, anil.s.keshavamurthy@intel.com, mark.rutland@arm.com, peterz@infradead.org, tianruidong@linux.alibaba.com Subject: [PATCH v13 2/3] PCI: trace: Add a RAS tracepoint to monitor link speed changes Date: Sat, 25 Oct 2025 19:41:57 +0800 Message-Id: <20251025114158.71714-3-xueshuai@linux.alibaba.com> X-Mailer: git-send-email 2.39.5 (Apple Git-154) In-Reply-To: <20251025114158.71714-1-xueshuai@linux.alibaba.com> References: <20251025114158.71714-1-xueshuai@linux.alibaba.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable PCIe link speed degradation directly impacts system performance and often indicates hardware issues such as faulty devices, physical layer problems, or configuration errors. To this end, add a RAS tracepoint to monitor link speed changes, enabling proactive health checks and diagnostic analysis. The following output is generated when a device is hotplugged: $ echo 1 > /sys/kernel/debug/tracing/events/pci/pcie_link_event/enable $ cat /sys/kernel/debug/tracing/trace_pipe irq/51-pciehp-88 [001] ..... 381.545386: pcie_link_event: 0000:00= :02.0 type:4, reason:4, cur_bus_speed:20, max_bus_speed:23, width:1, flit_m= ode:0, status:DLLLA Suggested-by: Ilpo J=C3=A4rvinen Suggested-by: Matthew W Carlis Suggested-by: Lukas Wunner Signed-off-by: Shuai Xue Reviewed-by: Ilpo J=C3=A4rvinen --- drivers/pci/hotplug/pciehp_hpc.c | 3 +- drivers/pci/pci.c | 2 +- drivers/pci/pci.h | 21 ++++++++++-- drivers/pci/pcie/bwctrl.c | 4 +-- drivers/pci/probe.c | 9 +++-- include/trace/events/pci.h | 57 ++++++++++++++++++++++++++++++++ 6 files changed, 87 insertions(+), 9 deletions(-) diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_= hpc.c index bcc51b26d03d..ad5f28f6a8b1 100644 --- a/drivers/pci/hotplug/pciehp_hpc.c +++ b/drivers/pci/hotplug/pciehp_hpc.c @@ -320,7 +320,8 @@ int pciehp_check_link_status(struct controller *ctrl) } =20 pcie_capability_read_word(pdev, PCI_EXP_LNKSTA2, &linksta2); - __pcie_update_link_speed(ctrl->pcie->port->subordinate, lnk_status, links= ta2); + __pcie_update_link_speed(ctrl->pcie->port->subordinate, PCIE_HOTPLUG, + lnk_status, linksta2); =20 if (!found) { ctrl_info(ctrl, "Slot(%s): No device found\n", diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index b14dd064006c..6a979a234fe6 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -4698,7 +4698,7 @@ int pcie_retrain_link(struct pci_dev *pdev, bool use_= lt) * Link Speed. */ if (pdev->subordinate) - pcie_update_link_speed(pdev->subordinate); + pcie_update_link_speed(pdev->subordinate, PCIE_LINK_RETRAIN); =20 return rc; } diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 4492b809094b..bc4de8fb4cba 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -5,6 +5,7 @@ #include #include #include +#include =20 struct pcie_tlp_log; =20 @@ -553,12 +554,28 @@ const char *pci_speed_string(enum pci_bus_speed speed= ); void __pcie_print_link_status(struct pci_dev *dev, bool verbose); void pcie_report_downtraining(struct pci_dev *dev); =20 -static inline void __pcie_update_link_speed(struct pci_bus *bus, u16 links= ta, u16 linksta2) +enum pcie_link_change_reason { + PCIE_LINK_RETRAIN, + PCIE_ADD_BUS, + PCIE_BWCTRL_ENABLE, + PCIE_BWCTRL_IRQ, + PCIE_HOTPLUG, +}; + +static inline void __pcie_update_link_speed(struct pci_bus *bus, + enum pcie_link_change_reason reason, + u16 linksta, u16 linksta2) { bus->cur_bus_speed =3D pcie_link_speed[linksta & PCI_EXP_LNKSTA_CLS]; bus->flit_mode =3D (linksta2 & PCI_EXP_LNKSTA2_FLIT) ? 1 : 0; + + trace_pcie_link_event(bus, + reason, + FIELD_GET(PCI_EXP_LNKSTA_NLW, linksta), + linksta & PCI_EXP_LNKSTA_LINK_STATUS_MASK); } -void pcie_update_link_speed(struct pci_bus *bus); + +void pcie_update_link_speed(struct pci_bus *bus, enum pcie_link_change_rea= son reason); =20 /* Single Root I/O Virtualization */ struct pci_sriov { diff --git a/drivers/pci/pcie/bwctrl.c b/drivers/pci/pcie/bwctrl.c index 36f939f23d34..32f1b30ecb84 100644 --- a/drivers/pci/pcie/bwctrl.c +++ b/drivers/pci/pcie/bwctrl.c @@ -199,7 +199,7 @@ static void pcie_bwnotif_enable(struct pcie_device *srv) * Update after enabling notifications & clearing status bits ensures * link speed is up to date. */ - pcie_update_link_speed(port->subordinate); + pcie_update_link_speed(port->subordinate, PCIE_BWCTRL_ENABLE); } =20 static void pcie_bwnotif_disable(struct pci_dev *port) @@ -234,7 +234,7 @@ static irqreturn_t pcie_bwnotif_irq(int irq, void *cont= ext) * speed (inside pcie_update_link_speed()) after LBMS has been * cleared to avoid missing link speed changes. */ - pcie_update_link_speed(port->subordinate); + pcie_update_link_speed(port->subordinate, PCIE_BWCTRL_IRQ); =20 return IRQ_HANDLED; } diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index c83e75a0ec12..d52f997ea476 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -22,6 +22,7 @@ #include #include #include +#include #include "pci.h" =20 #define CARDBUS_LATENCY_TIMER 176 /* secondary latency timer */ @@ -813,14 +814,16 @@ const char *pci_speed_string(enum pci_bus_speed speed) } EXPORT_SYMBOL_GPL(pci_speed_string); =20 -void pcie_update_link_speed(struct pci_bus *bus) +void pcie_update_link_speed(struct pci_bus *bus, + enum pcie_link_change_reason reason) { struct pci_dev *bridge =3D bus->self; u16 linksta, linksta2; =20 pcie_capability_read_word(bridge, PCI_EXP_LNKSTA, &linksta); pcie_capability_read_word(bridge, PCI_EXP_LNKSTA2, &linksta2); - __pcie_update_link_speed(bus, linksta, linksta2); + + __pcie_update_link_speed(bus, reason, linksta, linksta2); } EXPORT_SYMBOL_GPL(pcie_update_link_speed); =20 @@ -907,7 +910,7 @@ static void pci_set_bus_speed(struct pci_bus *bus) pcie_capability_read_dword(bridge, PCI_EXP_LNKCAP, &linkcap); bus->max_bus_speed =3D pcie_link_speed[linkcap & PCI_EXP_LNKCAP_SLS]; =20 - pcie_update_link_speed(bus); + pcie_update_link_speed(bus, PCIE_ADD_BUS); } } =20 diff --git a/include/trace/events/pci.h b/include/trace/events/pci.h index 39e512a167ee..9a9122f62fd3 100644 --- a/include/trace/events/pci.h +++ b/include/trace/events/pci.h @@ -5,6 +5,7 @@ #if !defined(_TRACE_HW_EVENT_PCI_H) || defined(TRACE_HEADER_MULTI_READ) #define _TRACE_HW_EVENT_PCI_H =20 +#include #include =20 #define PCI_HOTPLUG_EVENT \ @@ -66,6 +67,62 @@ TRACE_EVENT(pci_hp_event, ) ); =20 +#define PCI_EXP_LNKSTA_LINK_STATUS_MASK (PCI_EXP_LNKSTA_LBMS | \ + PCI_EXP_LNKSTA_LABS | \ + PCI_EXP_LNKSTA_LT | \ + PCI_EXP_LNKSTA_DLLLA) + +#define LNKSTA_FLAGS \ + { PCI_EXP_LNKSTA_LT, "LT"}, \ + { PCI_EXP_LNKSTA_DLLLA, "DLLLA"}, \ + { PCI_EXP_LNKSTA_LBMS, "LBMS"}, \ + { PCI_EXP_LNKSTA_LABS, "LABS"} + +TRACE_EVENT(pcie_link_event, + + TP_PROTO(struct pci_bus *bus, + unsigned int reason, + unsigned int width, + unsigned int status + ), + + TP_ARGS(bus, reason, width, status), + + TP_STRUCT__entry( + __string( port_name, pci_name(bus->self)) + __field( unsigned int, type ) + __field( unsigned int, reason ) + __field( unsigned int, cur_bus_speed ) + __field( unsigned int, max_bus_speed ) + __field( unsigned int, width ) + __field( unsigned int, flit_mode ) + __field( unsigned int, link_status ) + ), + + TP_fast_assign( + __assign_str(port_name); + __entry->type =3D pci_pcie_type(bus->self); + __entry->reason =3D reason; + __entry->cur_bus_speed =3D bus->cur_bus_speed; + __entry->max_bus_speed =3D bus->max_bus_speed; + __entry->width =3D width; + __entry->flit_mode =3D bus->flit_mode; + __entry->link_status =3D status; + ), + + TP_printk("%s type:%d, reason:%d, cur_bus_speed:%d, max_bus_speed:%d, wid= th:%u, flit_mode:%u, status:%s\n", + __get_str(port_name), + __entry->type, + __entry->reason, + __entry->cur_bus_speed, + __entry->max_bus_speed, + __entry->width, + __entry->flit_mode, + __print_flags((unsigned long)__entry->link_status, "|", + LNKSTA_FLAGS) + ) +); + #endif /* _TRACE_HW_EVENT_PCI_H */ =20 /* This part must be outside protection */ --=20 2.39.3 From nobody Sun Feb 8 09:27:53 2026 Received: from out30-133.freemail.mail.aliyun.com (out30-133.freemail.mail.aliyun.com [115.124.30.133]) (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 212052F9C2D; Sat, 25 Oct 2025 11:42:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.133 ARC-Seal: i=1; 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dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="wlLHMa77" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1761392531; h=From:To:Subject:Date:Message-Id:MIME-Version:Content-Type; bh=Mm2jJp1wLmcApPWwrk8ccMhyktrvri8iqqiwX1cdxII=; b=wlLHMa77i4X2ke81ANFJRnX4HH1shd4ltMQfuVXQKEkXyHXgRTRl9LHMSB+kR0CJTL4VYwkV40Vp2kd879M5MgKsulU/KVV0ruiXBcbc4yATjAq8ZYdqZCIgTtbBAJJGdaxT1PRKAPv4+s3Alb4BrZcHfioLrUwQFGKMqJ7XMrg= Received: from localhost.localdomain(mailfrom:xueshuai@linux.alibaba.com fp:SMTPD_---0WqwoUhW_1761392528 cluster:ay36) by smtp.aliyun-inc.com; Sat, 25 Oct 2025 19:42:09 +0800 From: Shuai Xue To: rostedt@goodmis.org, lukas@wunner.de, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-edac@vger.kernel.org, linux-trace-kernel@vger.kernel.org, helgaas@kernel.org, ilpo.jarvinen@linux.intel.com, mattc@purestorage.com, Jonathan.Cameron@huawei.com Cc: bhelgaas@google.com, tony.luck@intel.com, bp@alien8.de, xueshuai@linux.alibaba.com, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, oleg@redhat.com, naveen@kernel.org, davem@davemloft.net, anil.s.keshavamurthy@intel.com, mark.rutland@arm.com, peterz@infradead.org, tianruidong@linux.alibaba.com Subject: [PATCH v13 3/3] Documentation: tracing: Add documentation about PCI tracepoints Date: Sat, 25 Oct 2025 19:41:58 +0800 Message-Id: <20251025114158.71714-4-xueshuai@linux.alibaba.com> X-Mailer: git-send-email 2.39.5 (Apple Git-154) In-Reply-To: <20251025114158.71714-1-xueshuai@linux.alibaba.com> References: <20251025114158.71714-1-xueshuai@linux.alibaba.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable The PCI tracing system provides tracepoints to monitor critical hardware events that can impact system performance and reliability. Add documentation about it. Reviewed-by: Ilpo J=C3=A4rvinen Signed-off-by: Shuai Xue --- Documentation/trace/events-pci.rst | 74 ++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+) create mode 100644 Documentation/trace/events-pci.rst diff --git a/Documentation/trace/events-pci.rst b/Documentation/trace/event= s-pci.rst new file mode 100644 index 000000000000..88bd38fcc184 --- /dev/null +++ b/Documentation/trace/events-pci.rst @@ -0,0 +1,74 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D +Subsystem Trace Points: PCI +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D + +Overview +=3D=3D=3D=3D=3D=3D=3D=3D +The PCI tracing system provides tracepoints to monitor critical hardware e= vents +that can impact system performance and reliability. These events normally = show +up here: + + /sys/kernel/tracing/events/pci + +Cf. include/trace/events/pci.h for the events definitions. + +Available Tracepoints +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D + +pci_hp_event +------------ + +Monitors PCI hotplug events including card insertion/removal and link +state changes. +:: + + pci_hp_event "%s slot:%s, event:%s\n" + +**Event Types**: + +* ``LINK_UP`` - PCIe link established +* ``LINK_DOWN`` - PCIe link lost +* ``CARD_PRESENT`` - Card detected in slot +* ``CARD_NOT_PRESENT`` - Card removed from slot + +**Example Usage**: + + # Enable the tracepoint + echo 1> /sys/kernel/debug/tracing/events/pci/pci_hp_event/enable + + # Monitor events (the following output is generated when a device is h= otplugged) + cat /sys/kernel/debug/tracing/trace_pipe + irq/51-pciehp-88 [001] ..... 1311.177459: pci_hp_event: 0000:= 00:02.0 slot:10, event:CARD_PRESENT + + irq/51-pciehp-88 [001] ..... 1311.177566: pci_hp_event: 0000:= 00:02.0 slot:10, event:LINK_UP + +pcie_link_event +--------------- + +Monitors PCIe link speed changes and provides detailed link status informa= tion. +:: + + pcie_link_event "%s type:%d, reason:%d, cur_bus_speed:%s, max_bus_spe= ed:%s, width:%u, flit_mode:%u, status:%s\n" + +**Parameters**: + +* ``type`` - PCIe device type (4=3DRoot Port, etc.) +* ``reason`` - Reason for link change: + + - ``0`` - Link retrain + - ``1`` - Bus enumeration + - ``2`` - Bandwidth notification enable + - ``3`` - Bandwidth notification IRQ + - ``4`` - Hotplug event + + +**Example Usage**: + + # Enable the tracepoint + echo1 > /sys/kernel/debug/tracing/events/pci/pcie_link_event/enable + + # Monitor events (the following output is generated when a device is h= otplugged) + cat /sys/kernel/debug/tracing/trace_pipe + irq/51-pciehp-88 [001] ..... 381.545386: pcie_link_event: 00= 00:00:02.0 type:4, reason:4, cur_bus_speed:20, max_bus_speed:23, width:1, f= lit_mode:0, status:DLLLA --=20 2.39.3