From patchwork Fri Oct 9 07:59:31 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Daniel Vetter X-Patchwork-Id: 11825193 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 232CF175A for ; Fri, 9 Oct 2020 08:00:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E62AC222C2 for ; Fri, 9 Oct 2020 08:00:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ffwll.ch header.i=@ffwll.ch header.b="SipLyVLu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732758AbgJIIAP (ORCPT ); Fri, 9 Oct 2020 04:00:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49458 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732745AbgJIIAN (ORCPT ); Fri, 9 Oct 2020 04:00:13 -0400 Received: from mail-wr1-x442.google.com (mail-wr1-x442.google.com [IPv6:2a00:1450:4864:20::442]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8B726C0613D4 for ; Fri, 9 Oct 2020 01:00:13 -0700 (PDT) Received: by mail-wr1-x442.google.com with SMTP id t9so9227150wrq.11 for ; Fri, 09 Oct 2020 01:00:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=H+w/Nn7YNzQtL1R8HRvtzmLcceEG02qI4DQoPSHvskY=; b=SipLyVLu1maT+t1abz+yr4JywllfndSf6j6ENSrLq2AfSPXsjK05ajnSvbgqsompuC 1UhyDtuQjFpLpdHPLuaPJ1Y5re9PD8a0kaqxKFb6bu6P7peJGTnfxqpJ9GUn/cQVjw0m wfneMt3tfvx7mL59KoMFPgFV7khypHJ1pv88Y= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=H+w/Nn7YNzQtL1R8HRvtzmLcceEG02qI4DQoPSHvskY=; b=UNGHFZcRhxlv21e50jZmvwEh6kt2wBhC3I95H3ZiFkXoynWeO59YyN/kgL70pBVRPY zNVSrp2FCuY46VJgj0IzAkdUdrsadkpp00k86pB2HB9EphLBIkWR4h137BBb8BbftDVV zdLMIwE5ZTbNAKWAonDBZzlMq3kDCyJdak84Mpcy2SJzqn45bjvyJ1b5cPeu6MQ2jBVQ Wu08Ds0kTJCtv1UQC7uU9i1ELdixFbQmYpi3jyPiTBrnrLgFKWyAzQYqnmQUvD1WA+ch ySpu2IJEf387F2A4mZGZ+mXid82Sq/iMzS5RYeDW9rRDyn4lKSICpUqayWEhlidDL8mX Lyiw== X-Gm-Message-State: AOAM53129gpv7RbOdIr0NOyxRvsqm1Yw/jVWs1EcHBCj7JVgxA98ilee xsp3vJ8G1hu1JVyKUBKb9w6clQ== X-Google-Smtp-Source: ABdhPJwb1srE61RQrgeCbJO2ZU0Hri/NPq8TLZEHtmQEdkQpUeTbudhLIlI6H1MTzcH4vFJipHM18Q== X-Received: by 2002:adf:df91:: with SMTP id z17mr5138518wrl.379.1602230412191; Fri, 09 Oct 2020 01:00:12 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id u17sm11634118wri.45.2020.10.09.01.00.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 09 Oct 2020 01:00:11 -0700 (PDT) From: Daniel Vetter To: DRI Development , LKML Cc: kvm@vger.kernel.org, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-media@vger.kernel.org, linux-s390@vger.kernel.org, Daniel Vetter , Daniel Vetter , Jason Gunthorpe , Kees Cook , Dan Williams , Andrew Morton , John Hubbard , =?utf-8?b?SsOpcsO0bWUgR2xpc3Nl?= , Jan Kara , Arnd Bergmann , Greg Kroah-Hartman , David Hildenbrand , "Rafael J. Wysocki" Subject: [PATCH v2 14/17] resource: Move devmem revoke code to resource framework Date: Fri, 9 Oct 2020 09:59:31 +0200 Message-Id: <20201009075934.3509076-15-daniel.vetter@ffwll.ch> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201009075934.3509076-1-daniel.vetter@ffwll.ch> References: <20201009075934.3509076-1-daniel.vetter@ffwll.ch> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-samsung-soc@vger.kernel.org We want all iomem mmaps to consistently revoke ptes when the kernel takes over and CONFIG_IO_STRICT_DEVMEM is enabled. This includes the pci bar mmaps available through procfs and sysfs, which currently do not revoke mappings. To prepare for this, move the code from the /dev/kmem driver to kernel/resource.c. Signed-off-by: Daniel Vetter Cc: Jason Gunthorpe Cc: Kees Cook Cc: Dan Williams Cc: Andrew Morton Cc: John Hubbard Cc: Jérôme Glisse Cc: Jan Kara Cc: Dan Williams Cc: linux-mm@kvack.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-samsung-soc@vger.kernel.org Cc: linux-media@vger.kernel.org Cc: Arnd Bergmann Cc: Greg Kroah-Hartman Cc: Daniel Vetter Cc: David Hildenbrand Cc: "Rafael J. Wysocki" Reviewed-by: Greg Kroah-Hartman --- drivers/char/mem.c | 85 +------------------------------------ include/linux/ioport.h | 6 +-- kernel/resource.c | 95 +++++++++++++++++++++++++++++++++++++++++- 3 files changed, 96 insertions(+), 90 deletions(-) diff --git a/drivers/char/mem.c b/drivers/char/mem.c index 5502f56f3655..53338aad8d28 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -31,9 +31,6 @@ #include #include #include -#include -#include -#include #ifdef CONFIG_IA64 # include @@ -809,42 +806,6 @@ static loff_t memory_lseek(struct file *file, loff_t offset, int orig) return ret; } -static struct inode *devmem_inode; - -#ifdef CONFIG_IO_STRICT_DEVMEM -void revoke_devmem(struct resource *res) -{ - /* pairs with smp_store_release() in devmem_init_inode() */ - struct inode *inode = smp_load_acquire(&devmem_inode); - - /* - * Check that the initialization has completed. Losing the race - * is ok because it means drivers are claiming resources before - * the fs_initcall level of init and prevent /dev/mem from - * establishing mappings. - */ - if (!inode) - return; - - /* - * The expectation is that the driver has successfully marked - * the resource busy by this point, so devmem_is_allowed() - * should start returning false, however for performance this - * does not iterate the entire resource range. - */ - if (devmem_is_allowed(PHYS_PFN(res->start)) && - devmem_is_allowed(PHYS_PFN(res->end))) { - /* - * *cringe* iomem=relaxed says "go ahead, what's the - * worst that can happen?" - */ - return; - } - - unmap_mapping_range(inode->i_mapping, res->start, resource_size(res), 1); -} -#endif - static int open_port(struct inode *inode, struct file *filp) { int rc; @@ -864,7 +825,7 @@ static int open_port(struct inode *inode, struct file *filp) * revocations when drivers want to take over a /dev/mem mapped * range. */ - filp->f_mapping = inode->i_mapping; + filp->f_mapping = iomem_get_mapping(); return 0; } @@ -995,48 +956,6 @@ static char *mem_devnode(struct device *dev, umode_t *mode) static struct class *mem_class; -static int devmem_fs_init_fs_context(struct fs_context *fc) -{ - return init_pseudo(fc, DEVMEM_MAGIC) ? 0 : -ENOMEM; -} - -static struct file_system_type devmem_fs_type = { - .name = "devmem", - .owner = THIS_MODULE, - .init_fs_context = devmem_fs_init_fs_context, - .kill_sb = kill_anon_super, -}; - -static int devmem_init_inode(void) -{ - static struct vfsmount *devmem_vfs_mount; - static int devmem_fs_cnt; - struct inode *inode; - int rc; - - rc = simple_pin_fs(&devmem_fs_type, &devmem_vfs_mount, &devmem_fs_cnt); - if (rc < 0) { - pr_err("Cannot mount /dev/mem pseudo filesystem: %d\n", rc); - return rc; - } - - inode = alloc_anon_inode(devmem_vfs_mount->mnt_sb); - if (IS_ERR(inode)) { - rc = PTR_ERR(inode); - pr_err("Cannot allocate inode for /dev/mem: %d\n", rc); - simple_release_fs(&devmem_vfs_mount, &devmem_fs_cnt); - return rc; - } - - /* - * Publish /dev/mem initialized. - * Pairs with smp_load_acquire() in revoke_devmem(). - */ - smp_store_release(&devmem_inode, inode); - - return 0; -} - static int __init chr_dev_init(void) { int minor; @@ -1058,8 +977,6 @@ static int __init chr_dev_init(void) */ if ((minor == DEVPORT_MINOR) && !arch_has_dev_port()) continue; - if ((minor == DEVMEM_MINOR) && devmem_init_inode() != 0) - continue; device_create(mem_class, NULL, MKDEV(MEM_MAJOR, minor), NULL, devlist[minor].name); diff --git a/include/linux/ioport.h b/include/linux/ioport.h index 6c2b06fe8beb..8ffb61b36606 100644 --- a/include/linux/ioport.h +++ b/include/linux/ioport.h @@ -302,11 +302,7 @@ struct resource *devm_request_free_mem_region(struct device *dev, struct resource *request_free_mem_region(struct resource *base, unsigned long size, const char *name); -#ifdef CONFIG_IO_STRICT_DEVMEM -void revoke_devmem(struct resource *res); -#else -static inline void revoke_devmem(struct resource *res) { }; -#endif +extern struct address_space *iomem_get_mapping(void); #endif /* __ASSEMBLY__ */ #endif /* _LINUX_IOPORT_H */ diff --git a/kernel/resource.c b/kernel/resource.c index 841737bbda9e..22153fdec4f5 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -18,12 +18,15 @@ #include #include #include +#include #include #include #include #include #include +#include #include +#include #include @@ -1112,6 +1115,52 @@ resource_size_t resource_alignment(struct resource *res) static DECLARE_WAIT_QUEUE_HEAD(muxed_resource_wait); +static struct inode *iomem_inode; + +#ifdef CONFIG_IO_STRICT_DEVMEM +static void revoke_iomem(struct resource *res) +{ + /* pairs with smp_store_release() in iomem_init_inode() */ + struct inode *inode = smp_load_acquire(&iomem_inode); + + /* + * Check that the initialization has completed. Losing the race + * is ok because it means drivers are claiming resources before + * the fs_initcall level of init and prevent /dev/mem from + * establishing mappings. + */ + if (!inode) + return; + + /* + * The expectation is that the driver has successfully marked + * the resource busy by this point, so devmem_is_allowed() + * should start returning false, however for performance this + * does not iterate the entire resource range. + */ + if (devmem_is_allowed(PHYS_PFN(res->start)) && + devmem_is_allowed(PHYS_PFN(res->end))) { + /* + * *cringe* iomem=relaxed says "go ahead, what's the + * worst that can happen?" + */ + return; + } + + unmap_mapping_range(inode->i_mapping, res->start, resource_size(res), 1); +} +struct address_space *iomem_get_mapping(void) +{ + return iomem_inode->i_mapping; +} +#else +static void revoke_iomem(struct resource *res) {} +struct address_space *iomem_get_mapping(void) +{ + return NULL; +} +#endif + /** * __request_region - create a new busy resource region * @parent: parent resource descriptor @@ -1179,7 +1228,7 @@ struct resource * __request_region(struct resource *parent, write_unlock(&resource_lock); if (res && orig_parent == &iomem_resource) - revoke_devmem(res); + revoke_iomem(res); return res; } @@ -1713,4 +1762,48 @@ static int __init strict_iomem(char *str) return 1; } +static int iomem_fs_init_fs_context(struct fs_context *fc) +{ + return init_pseudo(fc, DEVMEM_MAGIC) ? 0 : -ENOMEM; +} + +static struct file_system_type iomem_fs_type = { + .name = "iomem", + .owner = THIS_MODULE, + .init_fs_context = iomem_fs_init_fs_context, + .kill_sb = kill_anon_super, +}; + +static int __init iomem_init_inode(void) +{ + static struct vfsmount *iomem_vfs_mount; + static int iomem_fs_cnt; + struct inode *inode; + int rc; + + rc = simple_pin_fs(&iomem_fs_type, &iomem_vfs_mount, &iomem_fs_cnt); + if (rc < 0) { + pr_err("Cannot mount iomem pseudo filesystem: %d\n", rc); + return rc; + } + + inode = alloc_anon_inode(iomem_vfs_mount->mnt_sb); + if (IS_ERR(inode)) { + rc = PTR_ERR(inode); + pr_err("Cannot allocate inode for iomem: %d\n", rc); + simple_release_fs(&iomem_vfs_mount, &iomem_fs_cnt); + return rc; + } + + /* + * Publish /dev/mem initialized. + * Pairs with smp_load_acquire() in revoke_iomem(). + */ + smp_store_release(&iomem_inode, inode); + + return 0; +} + +fs_initcall(iomem_init_inode); + __setup("iomem=", strict_iomem);