From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Thu, 05 Jun 2025 13:39:12 +0200 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by lore.white.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1uN8wC-003zqf-0k for lore@lore.pengutronix.de; Thu, 05 Jun 2025 13:39:12 +0200 Received: from bombadil.infradead.org ([2607:7c80:54:3::133]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1uN8wA-0002dO-Gz for lore@pengutronix.de; Thu, 05 Jun 2025 13:39:12 +0200 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=By/92BiYTm0ATaxlAn+ndWtdwNp/p6VXIqUkOvSTkuQ=; b=QAyqlRWBx9e/qZpGlAd0nRDFa1 1ANFWMTPP4vPqSOpgzudZkNEEEP9edL5AuTVfvnf48UUo8fa0altVTd+TI0rwiAnCigzT/iuOPwMu Mv1RpAp78cuqf1ky6pswELoNosWT8XfvKmUywkr5cvm+se6+NLRr22CG+AWTzcYe6seWVqHmdgLJ7 nmOgILjTYx8Hyar535Z/Jrsozj+39B6Wc/fH0fI6YF5OAzyEJSFTIoNF9xwiW8O6dmHQ+Z9zOkKgh L+zVsEkz93+cvzD1c0H0tO5cw/ubtHVxwg4GPpcHffGocFwDVWDOKuou1qqJMbwQPfyX9kA94uMEY q2dqsv1Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uN8vc-0000000FOZf-2KL3; Thu, 05 Jun 2025 11:38:36 +0000 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uN8vT-0000000FOOY-3Lf9 for barebox@lists.infradead.org; Thu, 05 Jun 2025 11:38:31 +0000 Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1uN8vS-0001jL-Jb; Thu, 05 Jun 2025 13:38:26 +0200 Received: from dude06.red.stw.pengutronix.de ([2a0a:edc0:0:1101:1d::5c]) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1uN8vS-001x0r-1J; Thu, 05 Jun 2025 13:38:26 +0200 Received: from localhost ([::1] helo=dude06.red.stw.pengutronix.de) by dude06.red.stw.pengutronix.de with esmtp (Exim 4.96) (envelope-from ) id 1uN8sg-008mT4-0L; Thu, 05 Jun 2025 13:35:33 +0200 From: Ahmad Fatoum To: barebox@lists.infradead.org Cc: Ahmad Fatoum Date: Thu, 5 Jun 2025 13:35:24 +0200 Message-Id: <20250605113530.2076990-16-a.fatoum@pengutronix.de> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250605113530.2076990-1-a.fatoum@pengutronix.de> References: <20250605113530.2076990-1-a.fatoum@pengutronix.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250605_043827_998964_855E405B X-CRM114-Status: GOOD ( 18.83 ) X-BeenThere: barebox@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "barebox" X-SA-Exim-Connect-IP: 2607:7c80:54:3::133 X-SA-Exim-Mail-From: barebox-bounces+lore=pengutronix.de@lists.infradead.org X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on metis.whiteo.stw.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-5.3 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE autolearn=unavailable autolearn_force=no version=3.4.2 Subject: [PATCH 15/21] block: add lightweight ramdisk support X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.whiteo.stw.pengutronix.de) The partitions code in barebox expects a block device to operate on and not raw memory buffers. Add an abstraction that wraps a raw memory buffer as block device in a very lightweight manner as not to impede fuzzing speed. Signed-off-by: Ahmad Fatoum --- drivers/block/Kconfig | 6 ++ drivers/block/Makefile | 1 + drivers/block/ramdisk.c | 178 ++++++++++++++++++++++++++++++++++++++++ include/ramdisk.h | 24 ++++++ 4 files changed, 209 insertions(+) create mode 100644 drivers/block/ramdisk.c create mode 100644 include/ramdisk.h diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig index bf8dfdbd5c12..5b1b7789171c 100644 --- a/drivers/block/Kconfig +++ b/drivers/block/Kconfig @@ -26,3 +26,9 @@ config EFI_BLK_SEPARATE_USBDISK for your disk and checking against it with devlookup -v $bootguid /dev/disk$bootsource_instance guid + +config RAMDISK_BLK + bool + help + This symbol is selected by testing code that requires lightweight + creation of anonymous block devices backed fully by memory buffers. diff --git a/drivers/block/Makefile b/drivers/block/Makefile index a4e14a559cf7..6066b35c313e 100644 --- a/drivers/block/Makefile +++ b/drivers/block/Makefile @@ -1,3 +1,4 @@ # SPDX-License-Identifier: GPL-2.0-only obj-$(CONFIG_EFI_BLK) += efi-block-io.o obj-$(CONFIG_VIRTIO_BLK) += virtio_blk.o +obj-$(CONFIG_RAMDISK_BLK) += ramdisk.o diff --git a/drivers/block/ramdisk.c b/drivers/block/ramdisk.c new file mode 100644 index 000000000000..6f3c9348058a --- /dev/null +++ b/drivers/block/ramdisk.c @@ -0,0 +1,178 @@ +// SPDX-License-Identifier: GPL-2.0-only +// lightweight anonymous block device wrapper around memory buffers + +#include +#include +#include +#include +#include +#include +#include +#include + +struct ramdisk { + struct block_device blk; + struct device dev; + union { + void *base_rw; + const void *base_ro; + }; + size_t size; + bool ro; +}; + +static int ramdisk_check_read(const struct ramdisk *ramdisk) +{ + return ramdisk->base_ro ? 1 : 0; +} + +static ssize_t ramdisk_read(struct cdev *cdev, void *buf, size_t count, + loff_t offset, unsigned long flags) +{ + struct ramdisk *ramdisk = cdev->priv; + size_t cpy_count, pad_count; + int ret; + + ret = ramdisk_check_read(ramdisk); + if (ret < 1) + return ret; + + if (size_add(offset, count) > ramdisk->size) + return -ENXIO; + + cpy_count = min_t(size_t, count, ramdisk->size - offset); + buf = mempcpy(buf, ramdisk->base_ro + offset, cpy_count); + + pad_count = min_t(size_t, count, cdev->size - offset) - cpy_count; + + memset(buf, 0x00, pad_count); + + pr_vdebug("read %zu bytes\n", cpy_count + pad_count); + + return cpy_count + pad_count; +} + +static int ramdisk_check_write(const struct ramdisk *ramdisk) +{ + if (!ramdisk->base_rw) + return -EPERM; + if (ramdisk->ro) + return -EACCES; + return 1; +} + +static ssize_t ramdisk_write(struct cdev *cdev, const void *buf, size_t count, + loff_t offset, unsigned long flags) +{ + struct ramdisk *ramdisk = cdev->priv; + int ret; + + ret = ramdisk_check_write(ramdisk); + if (ret < 1) + return ret; + if (size_add(offset, count) > ramdisk->size) + return -ENXIO; + + memcpy(ramdisk->base_rw + offset, buf, + min_t(size_t, count, ramdisk->size - offset)); + + return count; +} + +static int ramdisk_memmap(struct cdev *cdev, void **map, int flags) +{ + struct ramdisk *ramdisk = cdev->priv; + int ret; + + ret = flags & PROT_WRITE ? ramdisk_check_write(ramdisk) + : ramdisk_check_read(ramdisk); + if (ret < 1) + return ret; + + *map = ramdisk->base_rw; + return 0; +} + +static struct cdev_operations ramdisk_ops = { + .read = ramdisk_read, + .write = ramdisk_write, + .memmap = ramdisk_memmap, +}; + +struct ramdisk *ramdisk_init(int sector_size) +{ + struct ramdisk *ramdisk; + struct block_device *blk; + int ret; + + ramdisk = xzalloc(sizeof(*ramdisk)); + + dev_set_name(&ramdisk->dev, "ramdisk"); + ramdisk->dev.id = DEVICE_ID_DYNAMIC; + + ret = register_device(&ramdisk->dev); + if (ret) + return NULL; + + blk = &ramdisk->blk; + blk->dev = &ramdisk->dev; + blk->type = BLK_TYPE_VIRTUAL; + + blk->cdev.size = 0; + blk->cdev.name = xstrdup(dev_name(&ramdisk->dev)); + blk->cdev.dev = blk->dev; + blk->cdev.ops = &ramdisk_ops; + blk->cdev.priv = ramdisk; + blk->cdev.flags |= DEVFS_IS_BLOCK_DEV; + blk->blockbits = ilog2(sector_size); + + ret = devfs_create(&blk->cdev); + if (ret) + return NULL; + + INIT_LIST_HEAD(&blk->buffered_blocks); + INIT_LIST_HEAD(&blk->idle_blocks); + + return ramdisk; +} + +struct block_device *ramdisk_get_block_device(struct ramdisk *ramdisk) +{ + return &ramdisk->blk; +} + +void ramdisk_free(struct ramdisk *ramdisk) +{ + devfs_remove(&ramdisk->blk.cdev); + unregister_device(&ramdisk->dev); + free(ramdisk); +} + +static void ramdisk_setup_size(struct ramdisk *ramdisk, size_t size) +{ + ramdisk->size = size; + ramdisk->blk.cdev.size = ALIGN(size, 1 << ramdisk->blk.blockbits); +} + +void ramdisk_setup_ro(struct ramdisk *ramdisk, const void *data, size_t size) +{ + ramdisk->ro = true; + ramdisk->base_ro = data; + ramdisk_setup_size(ramdisk, size); +} + +const void *ramdisk_mmap(struct ramdisk *ramdisk, loff_t offset, + size_t size) +{ + if (size_add(offset, size) > ramdisk->size) + return NULL; + + return ramdisk->base_ro + offset; +} + +void ramdisk_setup_rw(struct ramdisk *ramdisk, void *data, size_t size) +{ + ramdisk->ro = false; + ramdisk->base_rw = data; + ramdisk_setup_size(ramdisk, size); +} diff --git a/include/ramdisk.h b/include/ramdisk.h new file mode 100644 index 000000000000..b256a9c12ca7 --- /dev/null +++ b/include/ramdisk.h @@ -0,0 +1,24 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#ifndef __RAMDISK_H_ +#define __RAMDISK_H_ + +#include + +struct ramdisk; +struct block_device; + +struct ramdisk *ramdisk_init(int sector_size); +void ramdisk_free(struct ramdisk *ramdisk); + +struct block_device *ramdisk_get_block_device(struct ramdisk *ramdisk); + +void ramdisk_setup_ro(struct ramdisk *ramdisk, const void *data, size_t size); +void ramdisk_setup_rw(struct ramdisk *ramdisk, void *data, size_t size); + +const void *ramdisk_mmap(struct ramdisk *ramdisk, loff_t offset, size_t size); +static inline void ramdisk_munmap(struct ramdisk *ramdisk, + void *ptr, loff_t offset, + size_t size) {} + +#endif -- 2.39.5