Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934787AbdCVNbv (ORCPT ); Wed, 22 Mar 2017 09:31:51 -0400 Received: from merlin.infradead.org ([205.233.59.134]:47280 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759633AbdCVNZd (ORCPT ); Wed, 22 Mar 2017 09:25:33 -0400 From: David Woodhouse To: linux-pci@vger.kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 04/17] pci: Add arch_can_pci_mmap_wc() macro Date: Wed, 22 Mar 2017 13:25:18 +0000 Message-Id: <11552df0208f8134f315f32217a3e033fe2174f4.1490188942.git.dwmw2@infradead.org> X-Mailer: git-send-email 2.9.3 In-Reply-To: References: In-Reply-To: References: X-SRS-Rewrite: SMTP reverse-path rewritten from by merlin.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6201 Lines: 171 From: David Woodhouse Most of the almost-identical versions of pci_mmap_page_range() silently ignore the 'write_combine' argument and give uncached mappings. Yet we allow the PCIIOC_WRITE_COMBINE ioctl in /proc/bus/pci, expose the 'resourceX_wc' file in sysfs, and allow an attempted mapping to apparently succeed. To fix this, introduce a macro arch_can_pci_mmap_wc() which indicates whether the platform can do a write-combining mapping. On x86 this ends up being pat_enabled(), while the few other platforms that support it can just set it to a literal '1'. Signed-off-by: David Woodhouse --- Documentation/filesystems/sysfs-pci.txt | 4 ++++ arch/ia64/include/asm/pci.h | 2 ++ arch/powerpc/include/asm/pci.h | 5 +++-- arch/x86/include/asm/pci.h | 2 ++ arch/xtensa/include/asm/pci.h | 6 +++++- arch/xtensa/kernel/pci.c | 2 +- drivers/pci/pci-sysfs.c | 6 ++++-- drivers/pci/proc.c | 17 ++++++++++------- 8 files changed, 31 insertions(+), 13 deletions(-) diff --git a/Documentation/filesystems/sysfs-pci.txt b/Documentation/filesystems/sysfs-pci.txt index 6ea1ced..25b7f1c 100644 --- a/Documentation/filesystems/sysfs-pci.txt +++ b/Documentation/filesystems/sysfs-pci.txt @@ -117,6 +117,10 @@ code must define HAVE_PCI_MMAP and provide a pci_mmap_page_range function. Platforms are free to only support subsets of the mmap functionality, but useful return codes should be provided. +Platforms which support write-combining maps of PCI resources must define +arch_can_pci_mmap_wc() which shall evaluate to non-zero at runtime when +write-combining is permitted. + Legacy resources are protected by the HAVE_PCI_LEGACY define. Platforms wishing to support legacy functionality should define it and provide pci_legacy_read, pci_legacy_write and pci_mmap_legacy_page_range functions. diff --git a/arch/ia64/include/asm/pci.h b/arch/ia64/include/asm/pci.h index c0835b0..6283758 100644 --- a/arch/ia64/include/asm/pci.h +++ b/arch/ia64/include/asm/pci.h @@ -51,6 +51,8 @@ extern unsigned long ia64_max_iommu_merge_mask; #define PCI_DMA_BUS_IS_PHYS (ia64_max_iommu_merge_mask == ~0UL) #define HAVE_PCI_MMAP +#define arch_can_pci_mmap_wc() 1 + extern int pci_mmap_page_range (struct pci_dev *dev, struct vm_area_struct *vma, enum pci_mmap_state mmap_state, int write_combine); #define HAVE_PCI_LEGACY diff --git a/arch/powerpc/include/asm/pci.h b/arch/powerpc/include/asm/pci.h index 93eded8..b5b68c6 100644 --- a/arch/powerpc/include/asm/pci.h +++ b/arch/powerpc/include/asm/pci.h @@ -81,8 +81,9 @@ struct vm_area_struct; int pci_mmap_page_range(struct pci_dev *pdev, struct vm_area_struct *vma, enum pci_mmap_state mmap_state, int write_combine); -/* Tell drivers/pci/proc.c that we have pci_mmap_page_range() */ -#define HAVE_PCI_MMAP 1 +/* Tell drivers/pci/proc.c that we have pci_mmap_page_range() and it does WC */ +#define HAVE_PCI_MMAP 1 +#define arch_can_pci_mmap_wc() 1 extern int pci_legacy_read(struct pci_bus *bus, loff_t port, u32 *val, size_t count); diff --git a/arch/x86/include/asm/pci.h b/arch/x86/include/asm/pci.h index 1411dbe..f6e22c2 100644 --- a/arch/x86/include/asm/pci.h +++ b/arch/x86/include/asm/pci.h @@ -7,6 +7,7 @@ #include #include #include +#include #include #ifdef __KERNEL__ @@ -102,6 +103,7 @@ int pcibios_set_irq_routing(struct pci_dev *dev, int pin, int irq); #define HAVE_PCI_MMAP +#define arch_can_pci_mmap_wc() pat_enabled() extern int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma, enum pci_mmap_state mmap_state, int write_combine); diff --git a/arch/xtensa/include/asm/pci.h b/arch/xtensa/include/asm/pci.h index 5d6bd93..f106879 100644 --- a/arch/xtensa/include/asm/pci.h +++ b/arch/xtensa/include/asm/pci.h @@ -51,7 +51,11 @@ int pci_mmap_page_range(struct pci_dev *pdev, struct vm_area_struct *vma, enum pci_mmap_state mmap_state, int write_combine); /* Tell drivers/pci/proc.c that we have pci_mmap_page_range() */ -#define HAVE_PCI_MMAP 1 +#define HAVE_PCI_MMAP 1 + +/* This was wrapped in #if 0 since the first merge of xtensa support... +#define arch_can_pci_mmap_wc() 1 +*/ #endif /* __KERNEL__ */ diff --git a/arch/xtensa/kernel/pci.c b/arch/xtensa/kernel/pci.c index b848cc3..c5944d3 100644 --- a/arch/xtensa/kernel/pci.c +++ b/arch/xtensa/kernel/pci.c @@ -345,7 +345,7 @@ __pci_mmap_set_pgprot(struct pci_dev *dev, struct vm_area_struct *vma, /* Set to write-through */ prot = (prot & _PAGE_CA_MASK) | _PAGE_CA_WT; -#if 0 +#ifdef arch_can_pci_mmap_wc if (!write_combine) prot |= _PAGE_WRITETHRU; #endif diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 7ac258f..cf2c7d8 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -1210,10 +1210,12 @@ static int pci_create_resource_files(struct pci_dev *pdev) continue; retval = pci_create_attr(pdev, i, 0); +#ifdef arch_can_pci_mmap_wc /* for prefetchable resources, create a WC mappable file */ - if (!retval && pdev->resource[i].flags & IORESOURCE_PREFETCH) + if (!retval && arch_can_pci_mmap_wc() && + pdev->resource[i].flags & IORESOURCE_PREFETCH) retval = pci_create_attr(pdev, i, 1); - +#endif if (retval) { pci_remove_resource_files(pdev); return retval; diff --git a/drivers/pci/proc.c b/drivers/pci/proc.c index dc8912e..c49be71 100644 --- a/drivers/pci/proc.c +++ b/drivers/pci/proc.c @@ -209,15 +209,18 @@ static long proc_bus_pci_ioctl(struct file *file, unsigned int cmd, fpriv->mmap_state = pci_mmap_mem; break; +#ifdef arch_can_pci_mmap_wc case PCIIOC_WRITE_COMBINE: - if (arg) - fpriv->write_combine = 1; - else - fpriv->write_combine = 0; - break; - + if (arch_can_pci_mmap_wc()) { + if (arg) + fpriv->write_combine = 1; + else + fpriv->write_combine = 0; + break; + } + /* If arch decided it can't, fall through... */ +#endif /* arch_can_pci_mmap_wc */ #endif /* HAVE_PCI_MMAP */ - default: ret = -EINVAL; break; -- 2.9.3