From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 45038C352A4 for ; Thu, 13 Feb 2020 01:04:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1A7B620714 for ; Thu, 13 Feb 2020 01:04:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729380AbgBMBE3 (ORCPT ); Wed, 12 Feb 2020 20:04:29 -0500 Received: from mga11.intel.com ([192.55.52.93]:57821 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729185AbgBMBE2 (ORCPT ); Wed, 12 Feb 2020 20:04:28 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 12 Feb 2020 17:04:26 -0800 X-IronPort-AV: E=Sophos;i="5.70,434,1574150400"; d="scan'208";a="380944448" Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.16]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 12 Feb 2020 17:04:27 -0800 Subject: [PATCH v2 1/4] mm/memremap_pages: Introduce memremap_compat_align() From: Dan Williams To: linux-nvdimm@lists.01.org Cc: "Aneesh Kumar K.V" , Jeff Moyer , Benjamin Herrenschmidt , Paul Mackerras , vishal.l.verma@intel.com, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Date: Wed, 12 Feb 2020 16:48:23 -0800 Message-ID: <158155490379.3343782.10305190793306743949.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <158155489850.3343782.2687127373754434980.stgit@dwillia2-desk3.amr.corp.intel.com> References: <158155489850.3343782.2687127373754434980.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.18-3-g996c MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The "sub-section memory hotplug" facility allows memremap_pages() users like libnvdimm to compensate for hardware platforms like x86 that have a section size larger than their hardware memory mapping granularity. The compensation that sub-section support affords is being tolerant of physical memory resources shifting by units smaller (64MiB on x86) than the memory-hotplug section size (128 MiB). Where the platform physical-memory mapping granularity is limited by the number and capability of address-decode-registers in the memory controller. While the sub-section support allows memremap_pages() to operate on sub-section (2MiB) granularity, the Power architecture may still require 16MiB alignment on "!radix_enabled()" platforms. In order for libnvdimm to be able to detect and manage this per-arch limitation, introduce memremap_compat_align() as a common minimum alignment across all driver-facing memory-mapping interfaces, and let Power override it to 16MiB in the "!radix_enabled()" case. The assumption / requirement for 16MiB to be a viable memremap_compat_align() value is that Power does not have platforms where its equivalent of address-decode-registers never hardware remaps a persistent memory resource on smaller than 16MiB boundaries. Note that I tried my best to not add a new Kconfig symbol, but header include entanglements defeated the #ifndef memremap_compat_align design pattern and the need to export it defeats the __weak design pattern for arch overrides. Based on an initial patch by Aneesh. Link: http://lore.kernel.org/r/CAPcyv4gBGNP95APYaBcsocEa50tQj9b5h__83vgngjq3ouGX_Q@mail.gmail.com Reported-by: Aneesh Kumar K.V Reported-by: Jeff Moyer Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Signed-off-by: Dan Williams --- arch/powerpc/Kconfig | 1 + arch/powerpc/mm/ioremap.c | 12 ++++++++++++ drivers/nvdimm/pfn_devs.c | 2 +- include/linux/memremap.h | 8 ++++++++ include/linux/mmzone.h | 1 + lib/Kconfig | 3 +++ mm/memremap.c | 13 +++++++++++++ 7 files changed, 39 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 497b7d0b2d7e..e6ffe905e2b9 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -122,6 +122,7 @@ config PPC select ARCH_HAS_GCOV_PROFILE_ALL select ARCH_HAS_KCOV select ARCH_HAS_HUGEPD if HUGETLB_PAGE + select ARCH_HAS_MEMREMAP_COMPAT_ALIGN select ARCH_HAS_MMIOWB if PPC64 select ARCH_HAS_PHYS_TO_DMA select ARCH_HAS_PMEM_API diff --git a/arch/powerpc/mm/ioremap.c b/arch/powerpc/mm/ioremap.c index fc669643ce6a..38b5ba7d3e2d 100644 --- a/arch/powerpc/mm/ioremap.c +++ b/arch/powerpc/mm/ioremap.c @@ -2,6 +2,7 @@ #include #include +#include #include #include @@ -97,3 +98,14 @@ void __iomem *do_ioremap(phys_addr_t pa, phys_addr_t offset, unsigned long size, return NULL; } + +#ifdef CONFIG_ZONE_DEVICE +/* override of the generic version in mm/memremap.c */ +unsigned long memremap_compat_align(void) +{ + if (radix_enabled()) + return SUBSECTION_SIZE; + return (1UL << mmu_psize_defs[mmu_linear_psize].shift); +} +EXPORT_SYMBOL_GPL(memremap_compat_align); +#endif diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c index b94f7a7e94b8..a5c25cb87116 100644 --- a/drivers/nvdimm/pfn_devs.c +++ b/drivers/nvdimm/pfn_devs.c @@ -750,7 +750,7 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn) start = nsio->res.start; size = resource_size(&nsio->res); npfns = PHYS_PFN(size - SZ_8K); - align = max(nd_pfn->align, (1UL << SUBSECTION_SHIFT)); + align = max(nd_pfn->align, SUBSECTION_SIZE); end_trunc = start + size - ALIGN_DOWN(start + size, align); if (nd_pfn->mode == PFN_MODE_PMEM) { /* diff --git a/include/linux/memremap.h b/include/linux/memremap.h index 6fefb09af7c3..8af1cbd8f293 100644 --- a/include/linux/memremap.h +++ b/include/linux/memremap.h @@ -132,6 +132,7 @@ struct dev_pagemap *get_dev_pagemap(unsigned long pfn, unsigned long vmem_altmap_offset(struct vmem_altmap *altmap); void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns); +unsigned long memremap_compat_align(void); #else static inline void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) @@ -165,6 +166,12 @@ static inline void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns) { } + +/* when memremap_pages() is disabled all archs can remap a single page */ +static inline unsigned long memremap_compat_align(void) +{ + return PAGE_SIZE; +} #endif /* CONFIG_ZONE_DEVICE */ static inline void put_dev_pagemap(struct dev_pagemap *pgmap) @@ -172,4 +179,5 @@ static inline void put_dev_pagemap(struct dev_pagemap *pgmap) if (pgmap) percpu_ref_put(pgmap->ref); } + #endif /* _LINUX_MEMREMAP_H_ */ diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 462f6873905a..6b77f7239af5 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -1170,6 +1170,7 @@ static inline unsigned long section_nr_to_pfn(unsigned long sec) #define SECTION_ALIGN_DOWN(pfn) ((pfn) & PAGE_SECTION_MASK) #define SUBSECTION_SHIFT 21 +#define SUBSECTION_SIZE (1UL << SUBSECTION_SHIFT) #define PFN_SUBSECTION_SHIFT (SUBSECTION_SHIFT - PAGE_SHIFT) #define PAGES_PER_SUBSECTION (1UL << PFN_SUBSECTION_SHIFT) diff --git a/lib/Kconfig b/lib/Kconfig index 0cf875fd627c..17dbc7bd3895 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -618,6 +618,9 @@ config ARCH_HAS_PMEM_API config MEMREGION bool +config ARCH_HAS_MEMREMAP_COMPAT_ALIGN + bool + # use memcpy to implement user copies for nommu architectures config UACCESS_MEMCPY bool diff --git a/mm/memremap.c b/mm/memremap.c index 09b5b7adc773..a6905d28fe91 100644 --- a/mm/memremap.c +++ b/mm/memremap.c @@ -7,6 +7,7 @@ #include #include #include +#include #include #include #include @@ -14,6 +15,18 @@ static DEFINE_XARRAY(pgmap_array); +/* + * Minimum compatible alignment of the resource (start, end) across + * memremap interfaces (i.e. memremap + memremap_pages) + */ +#ifndef CONFIG_ARCH_HAS_MEMREMAP_COMPAT_ALIGN +unsigned long memremap_compat_align(void) +{ + return SUBSECTION_SIZE; +} +EXPORT_SYMBOL_GPL(memremap_compat_align); +#endif + #ifdef CONFIG_DEV_PAGEMAP_OPS DEFINE_STATIC_KEY_FALSE(devmap_managed_key); EXPORT_SYMBOL(devmap_managed_key);