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=-12.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 7C9DBC8300A for ; Wed, 21 Oct 2020 08:57:38 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id F3FDE221FC for ; Wed, 21 Oct 2020 08:57:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=ffwll.ch header.i=@ffwll.ch header.b="AP3b3bdk" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F3FDE221FC Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ffwll.ch Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 5E3896B007E; Wed, 21 Oct 2020 04:57:25 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 51B466B0080; Wed, 21 Oct 2020 04:57:25 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3B9446B0081; Wed, 21 Oct 2020 04:57:25 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0212.hostedemail.com [216.40.44.212]) by kanga.kvack.org (Postfix) with ESMTP id 0E57B6B007E for ; Wed, 21 Oct 2020 04:57:25 -0400 (EDT) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id A58DC181AC9CC for ; Wed, 21 Oct 2020 08:57:24 +0000 (UTC) X-FDA: 77395328808.30.bite86_4507ab527247 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin30.hostedemail.com (Postfix) with ESMTP id 86A64180B3AA7 for ; Wed, 21 Oct 2020 08:57:24 +0000 (UTC) X-HE-Tag: bite86_4507ab527247 X-Filterd-Recvd-Size: 13009 Received: from mail-wm1-f67.google.com (mail-wm1-f67.google.com [209.85.128.67]) by imf33.hostedemail.com (Postfix) with ESMTP for ; Wed, 21 Oct 2020 08:57:23 +0000 (UTC) Received: by mail-wm1-f67.google.com with SMTP id b127so897550wmb.3 for ; Wed, 21 Oct 2020 01:57:23 -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=aBoKTxegCiMYpxvTLEwc8TlAefYzlvknZWTRI+Ydh8I=; b=AP3b3bdkrID/KzaTVFRe8yBWzxffBpMqEa8a/66Ihilc4X7chTOpPOcej7sCOj+Zmt uzZeTjVCQkjuk94tL2aloAYPRayTO1ekFtKuyvSI6Xc6NufbKHJpmlQtGBsN9hxcDphF /X6xa2Ycv9n8gk1zd9bL3dybzHcth4xgH0H8U= 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=aBoKTxegCiMYpxvTLEwc8TlAefYzlvknZWTRI+Ydh8I=; b=dFudccVlrVxFnP2zS3faPNir7t9iqxXS7An0et9MLj3Apg1KxWD6tUOfX8p8WwKAHX 8QT4rEnURDuA69Mo1Q1lqayDwWpA1awupaAQvyE73XO/v+IjyzfUAYTmbRt5QBxf6ahE h7Zj6JddZPsbhLyyQrDz5q/thgJa1r+w96Nn81gwUg+SSq5qDlI7U15fEh67grD0D0qX y5Kvi2F/O4HHfZnCVvcKCuJIbZQnwNZdfFa6htizqJAd1NRd3CGEhH89sVXQ4RguohD5 MXT+F4Xnym8SZaXSTA8F7tCc/iytKakrgHSLo73G5MZ8Cy9tm4O82dyERNT1yIQ+dk4P tfMA== X-Gm-Message-State: AOAM533RF47jlEYxYfbjBDciw74JPfx3vApEvoPjPc6VaRcXnhCObXy9 nxN5439L+JXA1tcYXzgwnYYJFg== X-Google-Smtp-Source: ABdhPJwf3DZZ9c6oKZg142+XtjY48SrUmrnpyP2WRRwtm3wxB8XXhaXev63lW8+C3ftX+U8SPjKoUQ== X-Received: by 2002:a1c:3103:: with SMTP id x3mr2427324wmx.107.1603270642920; Wed, 21 Oct 2020 01:57:22 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id q8sm2675939wro.32.2020.10.21.01.57.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 21 Oct 2020 01:57:22 -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 , Greg Kroah-Hartman , Daniel Vetter , Jason Gunthorpe , Kees Cook , Dan Williams , Andrew Morton , John Hubbard , =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= , Jan Kara , Arnd Bergmann , David Hildenbrand , "Rafael J. Wysocki" , Daniel Vetter Subject: [PATCH v3 14/16] resource: Move devmem revoke code to resource framework Date: Wed, 21 Oct 2020 10:56:53 +0200 Message-Id: <20201021085655.1192025-15-daniel.vetter@ffwll.ch> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201021085655.1192025-1-daniel.vetter@ffwll.ch> References: <20201021085655.1192025-1-daniel.vetter@ffwll.ch> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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. Reviewed-by: Greg Kroah-Hartman Signed-off-by: Daniel Vetter Cc: Jason Gunthorpe Cc: Kees Cook Cc: Dan Williams Cc: Andrew Morton Cc: John Hubbard Cc: J=C3=A9r=C3=B4me 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" Signed-off-by: Daniel Vetter -- v3: - add barrier for consistency and document why we don't have to check for NULL (Jason) --- drivers/char/mem.c | 85 +--------------------------------- include/linux/ioport.h | 6 +-- kernel/resource.c | 101 ++++++++++++++++++++++++++++++++++++++++- 3 files changed, 102 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 =20 #ifdef CONFIG_IA64 # include @@ -809,42 +806,6 @@ static loff_t memory_lseek(struct file *file, loff_t= offset, int orig) return ret; } =20 -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 =3D 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=3Drelaxed 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 =3D inode->i_mapping; + filp->f_mapping =3D iomem_get_mapping(); =20 return 0; } @@ -995,48 +956,6 @@ static char *mem_devnode(struct device *dev, umode_t= *mode) =20 static struct class *mem_class; =20 -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 =3D { - .name =3D "devmem", - .owner =3D THIS_MODULE, - .init_fs_context =3D devmem_fs_init_fs_context, - .kill_sb =3D 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 =3D 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 =3D alloc_anon_inode(devmem_vfs_mount->mnt_sb); - if (IS_ERR(inode)) { - rc =3D 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 =3D=3D DEVPORT_MINOR) && !arch_has_dev_port()) continue; - if ((minor =3D=3D DEVMEM_MINOR) && devmem_init_inode() !=3D 0) - continue; =20 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); =20 -#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); =20 #endif /* __ASSEMBLY__ */ #endif /* _LINUX_IOPORT_H */ diff --git a/kernel/resource.c b/kernel/resource.c index 841737bbda9e..a92fed5b9997 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 =20 =20 @@ -1112,6 +1115,58 @@ resource_size_t resource_alignment(struct resource= *res) =20 static DECLARE_WAIT_QUEUE_HEAD(muxed_resource_wait); =20 +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 =3D 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=3Drelaxed 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) +{ + /* + * This function is only called from file open paths, hence guaranteed + * that fs_initcalls have completed and no need to check for NULL. But + * since revoke_iomem can be called before the initcall we still need + * the barrier to appease checkers. + */ + return smp_load_acquire(&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 +1234,7 @@ struct resource * __request_region(struct resource = *parent, write_unlock(&resource_lock); =20 if (res && orig_parent =3D=3D &iomem_resource) - revoke_devmem(res); + revoke_iomem(res); =20 return res; } @@ -1713,4 +1768,48 @@ static int __init strict_iomem(char *str) return 1; } =20 +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 =3D { + .name =3D "iomem", + .owner =3D THIS_MODULE, + .init_fs_context =3D iomem_fs_init_fs_context, + .kill_sb =3D 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 =3D 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 =3D alloc_anon_inode(iomem_vfs_mount->mnt_sb); + if (IS_ERR(inode)) { + rc =3D 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=3D", strict_iomem); --=20 2.28.0