From nobody Mon Feb 9 21:19:18 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D4AD9C001DF for ; Thu, 13 Jul 2023 12:45:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234127AbjGMMpi (ORCPT ); Thu, 13 Jul 2023 08:45:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55526 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234093AbjGMMpg (ORCPT ); Thu, 13 Jul 2023 08:45:36 -0400 Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5A19226AF; Thu, 13 Jul 2023 05:45:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1689252332; x=1720788332; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=jZAmi7i2DsRxp8XcsCtYleiHASBL2jOVHHwz4RQm2Wc=; b=k+OQIxaytX04VSvJXU7XrZAQqVYIPC+V9Iwy9zuKMv7+M5EiAQH807XM mQqT5QI8ub75equdWJP6h1EZcqmKl2ig5iEluAI53mYWQyK3Mv/DRSQT+ R3fvY0MdwQ4oHJh66oYozkMxwqJcJbYJwlug3Msph8jhh0sB/E4qk7EzA Aj19Rmf9yLJf6+iTZxn/IxE4uHTexzEPepj1GZoaqDd43Yhxh6j/MCL8Z hWo+SAJBxPCnIsA86I9kdye2fiD4/PzHVJpTPVbvtOOEALWj0HKvRI6DF MORbnAOaFqGrBPPcydXBA+eShlO9sjO7Av55SGVGzlqcKedl7rrk6Sjlg Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10770"; a="367796760" X-IronPort-AV: E=Sophos;i="6.01,202,1684825200"; d="scan'208";a="367796760" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Jul 2023 05:45:31 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10770"; a="757144387" X-IronPort-AV: E=Sophos;i="6.01,202,1684825200"; d="scan'208";a="757144387" Received: from ijarvine-mobl2.ger.corp.intel.com ([10.251.222.39]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Jul 2023 05:45:18 -0700 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= To: linux-pci@vger.kernel.org, Bjorn Helgaas , Lorenzo Pieralisi , Rob Herring , =?UTF-8?q?Krzysztof=20Wilczy=C5=84ski?= , Emmanuel Grumbach , "Rafael J . Wysocki" , Heiner Kallweit , Lukas Wunner , "Rafael J. Wysocki" , Jesse Barnes , Yijing Wang , Jiang Liu , Shaohua Li , Greg Kroah-Hartman , Dean Luick , Mike Marciniszyn , Ira Weiny , Ashutosh Dixit , Doug Ledford , Ricky Wu , Rui Feng , Micky Ching , Lee Jones , Samuel Ortiz , Wei WANG , Daniel Bristot de Oliveira , "David S. Miller" , Michael Chan , Matt Carlson , Francois Romieu , Luiz Augusto von Dentz , Sven Peter , Bruce Allan , Jeff Kirsher , Auke Kok , Jeff Garzik , Vasanthakumar Thiagarajan , "John W. Linville" , Stanislaw Gruszka , Lorenzo Bianconi , Kalle Valo , Felix Fietkau , linux-kernel@vger.kernel.org Cc: Dean Luick , Andy Shevchenko , =?UTF-8?q?Jonas=20Dre=C3=9Fler?= , =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= , stable@vger.kernel.org Subject: [PATCH v4 01/11] PCI: Add locking to RMW PCI Express Capability Register accessors Date: Thu, 13 Jul 2023 15:44:55 +0300 Message-Id: <20230713124505.94866-2-ilpo.jarvinen@linux.intel.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20230713124505.94866-1-ilpo.jarvinen@linux.intel.com> References: <20230713124505.94866-1-ilpo.jarvinen@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Many places in the kernel write the Link Control and Root Control PCI Express Capability Registers without proper concurrency control and this could result in losing the changes one of the writers intended to make. Add pcie_cap_lock spinlock into the struct pci_dev and use it to protect bit changes made in the RMW capability accessors. Protect only a selected set of registers by differentiating the RMW accessor internally to locked/unlocked variants using a wrapper which has the same signature as pcie_capability_clear_and_set_word(). As the Capability Register (pos) given to the wrapper is always a constant, the compiler should be able to simplify all the dead-code away. So far only the Link Control Register (ASPM, hotplug, link retraining, various drivers) and the Root Control Register (AER & PME) seem to require RMW locking. Fixes: c7f486567c1d ("PCI PM: PCIe PME root port service driver") Fixes: f12eb72a268b ("PCI/ASPM: Use PCI Express Capability accessors") Fixes: 7d715a6c1ae5 ("PCI: add PCI Express ASPM support") Fixes: affa48de8417 ("staging/rdma/hfi1: Add support for enabling/disabling= PCIe ASPM") Fixes: 849a9366cba9 ("misc: rtsx: Add support new chip rts5228 mmc: rtsx: A= dd support MMC_CAP2_NO_MMC") Fixes: 3d1e7aa80d1c ("misc: rtsx: Use pcie_capability_clear_and_set_word() = for PCI_EXP_LNKCTL") Fixes: c0e5f4e73a71 ("misc: rtsx: Add support for RTS5261") Fixes: 3df4fce739e2 ("misc: rtsx: separate aspm mode into MODE_REG and MODE= _CFG") Fixes: 121e9c6b5c4c ("misc: rtsx: modify and fix init_hw function") Fixes: 19f3bd548f27 ("mfd: rtsx: Remove LCTLR defination") Fixes: 773ccdfd9cc6 ("mfd: rtsx: Read vendor setting from config space") Fixes: 8275b77a1513 ("mfd: rts5249: Add support for RTS5250S power saving") Fixes: 5da4e04ae480 ("misc: rtsx: Add support for RTS5260") Fixes: 0f49bfbd0f2e ("tg3: Use PCI Express Capability accessors") Fixes: 5e7dfd0fb94a ("tg3: Prevent corruption at 10 / 100Mbps w CLKREQ") Fixes: b726e493e8dc ("r8169: sync existing 8168 device hardware start seque= nces with vendor driver") Fixes: e6de30d63eb1 ("r8169: more 8168dp support.") Fixes: 8a06127602de ("Bluetooth: hci_bcm4377: Add new driver for BCM4377 PC= Ie boards") Fixes: 6f461f6c7c96 ("e1000e: enable/disable ASPM L0s and L1 and ERT accord= ing to hardware errata") Fixes: 1eae4eb2a1c7 ("e1000e: Disable L1 ASPM power savings for 82573 mobil= e variants") Fixes: 8060e169e02f ("ath9k: Enable extended synch for AR9485 to fix L0s re= covery issue") Fixes: 69ce674bfa69 ("ath9k: do btcoex ASPM disabling at initialization tim= e") Fixes: f37f05503575 ("mt76: mt76x2e: disable pcie_aspm by default") Suggested-by: Lukas Wunner Signed-off-by: Ilpo J=C3=A4rvinen Reviewed-by: Rafael J. Wysocki Cc: stable@vger.kernel.org --- drivers/pci/access.c | 20 +++++++++++++++++--- drivers/pci/probe.c | 1 + include/linux/pci.h | 34 ++++++++++++++++++++++++++++++++-- 3 files changed, 50 insertions(+), 5 deletions(-) diff --git a/drivers/pci/access.c b/drivers/pci/access.c index 3c230ca3de58..0b2e90d2f04f 100644 --- a/drivers/pci/access.c +++ b/drivers/pci/access.c @@ -497,8 +497,8 @@ int pcie_capability_write_dword(struct pci_dev *dev, in= t pos, u32 val) } EXPORT_SYMBOL(pcie_capability_write_dword); =20 -int pcie_capability_clear_and_set_word(struct pci_dev *dev, int pos, - u16 clear, u16 set) +int pcie_capability_clear_and_set_word_unlocked(struct pci_dev *dev, int p= os, + u16 clear, u16 set) { int ret; u16 val; @@ -512,7 +512,21 @@ int pcie_capability_clear_and_set_word(struct pci_dev = *dev, int pos, =20 return ret; } -EXPORT_SYMBOL(pcie_capability_clear_and_set_word); +EXPORT_SYMBOL(pcie_capability_clear_and_set_word_unlocked); + +int pcie_capability_clear_and_set_word_locked(struct pci_dev *dev, int pos, + u16 clear, u16 set) +{ + unsigned long flags; + int ret; + + spin_lock_irqsave(&dev->pcie_cap_lock, flags); + ret =3D pcie_capability_clear_and_set_word_unlocked(dev, pos, clear, set); + spin_unlock_irqrestore(&dev->pcie_cap_lock, flags); + + return ret; +} +EXPORT_SYMBOL(pcie_capability_clear_and_set_word_locked); =20 int pcie_capability_clear_and_set_dword(struct pci_dev *dev, int pos, u32 clear, u32 set) diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 8bac3ce02609..f1587fb0ba71 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -2324,6 +2324,7 @@ struct pci_dev *pci_alloc_dev(struct pci_bus *bus) .end =3D -1, }; =20 + spin_lock_init(&dev->pcie_cap_lock); #ifdef CONFIG_PCI_MSI raw_spin_lock_init(&dev->msi_lock); #endif diff --git a/include/linux/pci.h b/include/linux/pci.h index c69a2cc1f412..7ee498cd1f37 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -467,6 +467,7 @@ struct pci_dev { pci_dev_flags_t dev_flags; atomic_t enable_cnt; /* pci_enable_device has been called */ =20 + spinlock_t pcie_cap_lock; /* Protects RMW ops in capability accessors */ u32 saved_config_space[16]; /* Config space saved at suspend time */ struct hlist_head saved_cap_space; int rom_attr_enabled; /* Display of ROM attribute enabled? */ @@ -1217,11 +1218,40 @@ int pcie_capability_read_word(struct pci_dev *dev, = int pos, u16 *val); int pcie_capability_read_dword(struct pci_dev *dev, int pos, u32 *val); int pcie_capability_write_word(struct pci_dev *dev, int pos, u16 val); int pcie_capability_write_dword(struct pci_dev *dev, int pos, u32 val); -int pcie_capability_clear_and_set_word(struct pci_dev *dev, int pos, - u16 clear, u16 set); +int pcie_capability_clear_and_set_word_unlocked(struct pci_dev *dev, int p= os, + u16 clear, u16 set); +int pcie_capability_clear_and_set_word_locked(struct pci_dev *dev, int pos, + u16 clear, u16 set); int pcie_capability_clear_and_set_dword(struct pci_dev *dev, int pos, u32 clear, u32 set); =20 +/** + * pcie_capability_clear_and_set_word - RMW accessor for PCI Express Capab= ility Registers + * @dev: PCI device structure of the PCI Express device + * @pos: PCI Express Capability Register + * @clear: Clear bitmask + * @set: Set bitmask + * + * Perform a Read-Modify-Write (RMW) operation using @clear and @set + * bitmasks on PCI Express Capability Register at @pos. Certain PCI Express + * Capability Registers are accessed concurrently in RMW fashion, hence + * require locking which is handled transparently to the caller. + */ +static inline int pcie_capability_clear_and_set_word(struct pci_dev *dev, + int pos, + u16 clear, u16 set) +{ + switch (pos) { + case PCI_EXP_LNKCTL: + case PCI_EXP_RTCTL: + return pcie_capability_clear_and_set_word_locked(dev, pos, + clear, set); + default: + return pcie_capability_clear_and_set_word_unlocked(dev, pos, + clear, set); + } +} + static inline int pcie_capability_set_word(struct pci_dev *dev, int pos, u16 set) { --=20 2.30.2