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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,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 73F07C433ED for ; Fri, 30 Apr 2021 05:57:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4BCD961481 for ; Fri, 30 Apr 2021 05:57:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229684AbhD3F6V (ORCPT ); Fri, 30 Apr 2021 01:58:21 -0400 Received: from mail.kernel.org ([198.145.29.99]:51468 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229591AbhD3F6U (ORCPT ); Fri, 30 Apr 2021 01:58:20 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id B2D2A6147E; Fri, 30 Apr 2021 05:57:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1619762253; bh=hZaq+1o4beWdyFlZwzMfP3abChp1wAAa1Hp2+PZGm84=; h=Date:From:To:Subject:In-Reply-To:From; b=ZjshwFDlO475lLXKUAdxgyIuwUkvwDpjW/fUYQXvGeg56rAdppv/j80IPsl/wAZ1D m6+WSGy0T3yRVxJNFGmJu1R+SNOoSMUZjTFuFvcAiEju8JLq1FHz2Yj1taWlbH+LXG +L3euwYruY0JP7OyDKghuZwoHiaM6yK84pgjdgUc= Date: Thu, 29 Apr 2021 22:57:32 -0700 From: Andrew Morton To: akpm@linux-foundation.org, chris@chris-wilson.co.uk, daniel.vetter@ffwll.ch, hch@lst.de, jani.nikula@linux.intel.com, joonas.lahtinen@linux.intel.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, peterz@infradead.org, rodrigo.vivi@intel.com, torvalds@linux-foundation.org Subject: [patch 085/178] mm: add a io_mapping_map_user helper Message-ID: <20210430055732.qR4FYpcMj%akpm@linux-foundation.org> In-Reply-To: <20210429225251.02b6386d21b69255b4f6c163@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Christoph Hellwig Subject: mm: add a io_mapping_map_user helper Add a helper that calls remap_pfn_range for an struct io_mapping, relying on the pgprot pre-validation done when creating the mapping instead of doing it at runtime. Link: https://lkml.kernel.org/r/20210326055505.1424432-3-hch@lst.de Signed-off-by: Christoph Hellwig Cc: Chris Wilson Cc: Daniel Vetter Cc: Jani Nikula Cc: Joonas Lahtinen Cc: Peter Zijlstra Cc: Rodrigo Vivi Signed-off-by: Andrew Morton --- include/linux/io-mapping.h | 3 +++ mm/Kconfig | 3 +++ mm/Makefile | 1 + mm/io-mapping.c | 29 +++++++++++++++++++++++++++++ 4 files changed, 36 insertions(+) --- a/include/linux/io-mapping.h~mm-add-a-io_mapping_map_user-helper +++ a/include/linux/io-mapping.h @@ -220,3 +220,6 @@ io_mapping_free(struct io_mapping *iomap } #endif /* _LINUX_IO_MAPPING_H */ + +int io_mapping_map_user(struct io_mapping *iomap, struct vm_area_struct *vma, + unsigned long addr, unsigned long pfn, unsigned long size); --- /dev/null +++ a/mm/io-mapping.c @@ -0,0 +1,29 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#include +#include + +/** + * io_mapping_map_user - remap an I/O mapping to userspace + * @iomap: the source io_mapping + * @vma: user vma to map to + * @addr: target user address to start at + * @pfn: physical address of kernel memory + * @size: size of map area + * + * Note: this is only safe if the mm semaphore is held when called. + */ +int io_mapping_map_user(struct io_mapping *iomap, struct vm_area_struct *vma, + unsigned long addr, unsigned long pfn, unsigned long size) +{ + vm_flags_t expected_flags = VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; + + if (WARN_ON_ONCE((vma->vm_flags & expected_flags) != expected_flags)) + return -EINVAL; + + /* We rely on prevalidation of the io-mapping to skip track_pfn(). */ + return remap_pfn_range_notrack(vma, addr, pfn, size, + __pgprot((pgprot_val(iomap->prot) & _PAGE_CACHE_MASK) | + (pgprot_val(vma->vm_page_prot) & ~_PAGE_CACHE_MASK))); +} +EXPORT_SYMBOL_GPL(io_mapping_map_user); --- a/mm/Kconfig~mm-add-a-io_mapping_map_user-helper +++ a/mm/Kconfig @@ -871,4 +871,7 @@ config MAPPING_DIRTY_HELPERS config KMAP_LOCAL bool +# struct io_mapping based helper. Selected by drivers that need them +config IO_MAPPING + bool endmenu --- a/mm/Makefile~mm-add-a-io_mapping_map_user-helper +++ a/mm/Makefile @@ -120,3 +120,4 @@ obj-$(CONFIG_MEMFD_CREATE) += memfd.o obj-$(CONFIG_MAPPING_DIRTY_HELPERS) += mapping_dirty_helpers.o obj-$(CONFIG_PTDUMP_CORE) += ptdump.o obj-$(CONFIG_PAGE_REPORTING) += page_reporting.o +obj-$(CONFIG_IO_MAPPING) += io-mapping.o _