Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit add710ea authored by Johan Rudholm's avatar Johan Rudholm Committed by Chris Ball
Browse files

mmc: boot partition ro lock support 



Enable boot partitions to be read-only locked until next power on via
a sysfs entry. There will be one sysfs entry for each boot partition:

/sys/block/mmcblkXbootY/ro_lock_until_next_power_on

Each boot partition is locked by writing 1 to its file.

Signed-off-by: default avatarJohan Rudholm <johan.rudholm@stericsson.com>
Signed-off-by: default avatarJohn Beckett <john.beckett@stericsson.com>
Signed-off-by: default avatarChris Ball <cjb@laptop.org>
parent 92df954d

Documentation/mmc/mmc-dev-parts.txt

+13 −0
Original line number Diff line number Diff line
@@ -25,3 +25,16 @@ echo 0 > /sys/block/mmcblkXbootY/force_ro 
To re-enable read-only access:



echo 1 > /sys/block/mmcblkXbootY/force_ro



The boot partitions can also be locked read only until the next power on,

with:



echo 1 > /sys/block/mmcblkXbootY/ro_lock_until_next_power_on



This is a feature of the card and not of the kernel. If the card does

not support boot partition locking, the file will not exist. If the

feature has been disabled on the card, the file will be read-only.



The boot partitions can also be locked permanently, but this feature is

not accessible through sysfs in order to avoid accidental or malicious

bricking.

drivers/mmc/card/block.c

+113 −8
Original line number Diff line number Diff line
@@ -107,6 +107,8 @@ struct mmc_blk_data { 
	 */

	unsigned int	part_curr;

	struct device_attribute force_ro;

	struct device_attribute power_ro_lock;

	int	area_type;

};



static DEFINE_MUTEX(open_lock);
@@ -165,6 +167,70 @@ static void mmc_blk_put(struct mmc_blk_data *md) 
	mutex_unlock(&open_lock);

}



static ssize_t power_ro_lock_show(struct device *dev,

		struct device_attribute *attr, char *buf)

{

	int ret;

	struct mmc_blk_data *md = mmc_blk_get(dev_to_disk(dev));

	struct mmc_card *card = md->queue.card;

	int locked = 0;



	if (card->ext_csd.boot_ro_lock & EXT_CSD_BOOT_WP_B_PERM_WP_EN)

		locked = 2;

	else if (card->ext_csd.boot_ro_lock & EXT_CSD_BOOT_WP_B_PWR_WP_EN)

		locked = 1;



	ret = snprintf(buf, PAGE_SIZE, "%d\n", locked);



	return ret;

}



static ssize_t power_ro_lock_store(struct device *dev,

		struct device_attribute *attr, const char *buf, size_t count)

{

	int ret;

	struct mmc_blk_data *md, *part_md;

	struct mmc_card *card;

	unsigned long set;



	if (kstrtoul(buf, 0, &set))

		return -EINVAL;



	if (set != 1)

		return count;



	md = mmc_blk_get(dev_to_disk(dev));

	card = md->queue.card;



	mmc_claim_host(card->host);



	ret = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_BOOT_WP,

				card->ext_csd.boot_ro_lock |

				EXT_CSD_BOOT_WP_B_PWR_WP_EN,

				card->ext_csd.part_time);

	if (ret)

		pr_err("%s: Locking boot partition ro until next power on failed: %d\n", md->disk->disk_name, ret);

	else

		card->ext_csd.boot_ro_lock |= EXT_CSD_BOOT_WP_B_PWR_WP_EN;



	mmc_release_host(card->host);



	if (!ret) {

		pr_info("%s: Locking boot partition ro until next power on\n",

			md->disk->disk_name);

		set_disk_ro(md->disk, 1);



		list_for_each_entry(part_md, &md->part, part)

			if (part_md->area_type == MMC_BLK_DATA_AREA_BOOT) {

				pr_info("%s: Locking boot partition ro until next power on\n", part_md->disk->disk_name);

				set_disk_ro(part_md->disk, 1);

			}

	}



	mmc_blk_put(md);

	return count;

}



static ssize_t force_ro_show(struct device *dev, struct device_attribute *attr,

			     char *buf)

{
@@ -1347,7 +1413,8 @@ static struct mmc_blk_data *mmc_blk_alloc_req(struct mmc_card *card, 
					      struct device *parent,

					      sector_t size,

					      bool default_ro,

					      const char *subname)

					      const char *subname,

					      int area_type)

{

	struct mmc_blk_data *md;

	int devidx, ret;
@@ -1372,11 +1439,12 @@ static struct mmc_blk_data *mmc_blk_alloc_req(struct mmc_card *card, 
	if (!subname) {

		md->name_idx = find_first_zero_bit(name_use, max_devices);

		__set_bit(md->name_idx, name_use);

	}

	else

	} else

		md->name_idx = ((struct mmc_blk_data *)

				dev_to_disk(parent)->private_data)->name_idx;



	md->area_type = area_type;



	/*

	 * Set the read-only status based on the supported commands

	 * and the write protect switch.
@@ -1470,7 +1538,8 @@ static struct mmc_blk_data *mmc_blk_alloc(struct mmc_card *card) 
		size = card->csd.capacity << (card->csd.read_blkbits - 9);

	}



	md = mmc_blk_alloc_req(card, &card->dev, size, false, NULL);

	md = mmc_blk_alloc_req(card, &card->dev, size, false, NULL,

					MMC_BLK_DATA_AREA_MAIN);

	return md;

}
@@ -1479,13 +1548,14 @@ static int mmc_blk_alloc_part(struct mmc_card *card, 
			      unsigned int part_type,

			      sector_t size,

			      bool default_ro,

			      const char *subname)

			      const char *subname,

			      int area_type)

{

	char cap_str[10];

	struct mmc_blk_data *part_md;



	part_md = mmc_blk_alloc_req(card, disk_to_dev(md->disk), size, default_ro,

				    subname);

				    subname, area_type);

	if (IS_ERR(part_md))

		return PTR_ERR(part_md);

	part_md->part_type = part_type;
@@ -1518,7 +1588,8 @@ static int mmc_blk_alloc_parts(struct mmc_card *card, struct mmc_blk_data *md) 
				card->part[idx].part_cfg,

				card->part[idx].size >> 9,

				card->part[idx].force_ro,

				card->part[idx].name);

				card->part[idx].name,

				card->part[idx].area_type);

			if (ret)

				return ret;

		}
@@ -1547,9 +1618,16 @@ mmc_blk_set_blksize(struct mmc_blk_data *md, struct mmc_card *card) 


static void mmc_blk_remove_req(struct mmc_blk_data *md)

{

	struct mmc_card *card;



	if (md) {

		card = md->queue.card;

		if (md->disk->flags & GENHD_FL_UP) {

			device_remove_file(disk_to_dev(md->disk), &md->force_ro);

			if ((md->area_type & MMC_BLK_DATA_AREA_BOOT) &&

					card->ext_csd.boot_ro_lockable)

				device_remove_file(disk_to_dev(md->disk),

					&md->power_ro_lock);



			/* Stop new requests from getting into the queue */

			del_gendisk(md->disk);
@@ -1578,6 +1656,7 @@ static void mmc_blk_remove_parts(struct mmc_card *card, 
static int mmc_add_disk(struct mmc_blk_data *md)

{

	int ret;

	struct mmc_card *card = md->queue.card;



	add_disk(md->disk);

	md->force_ro.show = force_ro_show;
@@ -1587,6 +1666,32 @@ static int mmc_add_disk(struct mmc_blk_data *md) 
	md->force_ro.attr.mode = S_IRUGO | S_IWUSR;

	ret = device_create_file(disk_to_dev(md->disk), &md->force_ro);

	if (ret)

		goto force_ro_fail;



	if ((md->area_type & MMC_BLK_DATA_AREA_BOOT) &&

	     card->ext_csd.boot_ro_lockable) {

		mode_t mode;



		if (card->ext_csd.boot_ro_lock & EXT_CSD_BOOT_WP_B_PWR_WP_DIS)

			mode = S_IRUGO;

		else

			mode = S_IRUGO | S_IWUSR;



		md->power_ro_lock.show = power_ro_lock_show;

		md->power_ro_lock.store = power_ro_lock_store;

		md->power_ro_lock.attr.mode = mode;

		md->power_ro_lock.attr.name =

					"ro_lock_until_next_power_on";

		ret = device_create_file(disk_to_dev(md->disk),

				&md->power_ro_lock);

		if (ret)

			goto power_ro_lock_fail;

	}

	return ret;



power_ro_lock_fail:

	device_remove_file(disk_to_dev(md->disk), &md->force_ro);

force_ro_fail:

	del_gendisk(md->disk);



	return ret;

drivers/mmc/core/mmc.c

+12 −2
Original line number Diff line number Diff line
@@ -348,7 +348,8 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd) 
				part_size = ext_csd[EXT_CSD_BOOT_MULT] << 17;

				mmc_part_add(card, part_size,

					EXT_CSD_PART_CONFIG_ACC_BOOT0 + idx,

					"boot%d", idx, true);

					"boot%d", idx, true,

					MMC_BLK_DATA_AREA_BOOT);

			}

		}

	}
@@ -435,7 +436,8 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd) 
					hc_wp_grp_sz);

				mmc_part_add(card, part_size << 19,

					EXT_CSD_PART_CONFIG_ACC_GP0 + idx,

					"gp%d", idx, false);

					"gp%d", idx, false,

					MMC_BLK_DATA_AREA_GP);

			}

		}

		card->ext_csd.sec_trim_mult =
@@ -446,6 +448,14 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd) 
			ext_csd[EXT_CSD_SEC_FEATURE_SUPPORT];

		card->ext_csd.trim_timeout = 300 *

			ext_csd[EXT_CSD_TRIM_MULT];



		/*

		 * Note that the call to mmc_part_add above defaults to read

		 * only. If this default assumption is changed, the call must

		 * take into account the value of boot_locked below.

		 */

		card->ext_csd.boot_ro_lock = ext_csd[EXT_CSD_BOOT_WP];

		card->ext_csd.boot_ro_lockable = true;

	}



	if (card->ext_csd.rev >= 5) {

include/linux/mmc/card.h

+9 −1
Original line number Diff line number Diff line
@@ -71,6 +71,8 @@ struct mmc_ext_csd { 
	bool			hpi_en;			/* HPI enablebit */

	bool			hpi;			/* HPI support bit */

	unsigned int		hpi_cmd;		/* cmd used as HPI */

	unsigned int		boot_ro_lock;		/* ro lock support */

	bool			boot_ro_lockable;

	u8			raw_partition_support;	/* 160 */

	u8			raw_erased_mem_count;	/* 181 */

	u8			raw_ext_csd_structure;	/* 194 */
@@ -187,6 +189,10 @@ struct mmc_part { 
	unsigned int	part_cfg;	/* partition type */

	char	name[MAX_MMC_PART_NAME_LEN];

	bool	force_ro;	/* to make boot parts RO by default */

	unsigned int	area_type;

#define MMC_BLK_DATA_AREA_MAIN	(1<<0)

#define MMC_BLK_DATA_AREA_BOOT	(1<<1)

#define MMC_BLK_DATA_AREA_GP	(1<<2)

};



/*
@@ -265,12 +271,14 @@ struct mmc_card { 
 * This function fill contents in mmc_part.

 */

static inline void mmc_part_add(struct mmc_card *card, unsigned int size,

			unsigned int part_cfg, char *name, int idx, bool ro)

			unsigned int part_cfg, char *name, int idx, bool ro,

			int area_type)

{

	card->part[card->nr_parts].size = size;

	card->part[card->nr_parts].part_cfg = part_cfg;

	sprintf(card->part[card->nr_parts].name, name, idx);

	card->part[card->nr_parts].force_ro = ro;

	card->part[card->nr_parts].area_type = area_type;

	card->nr_parts++;

}

include/linux/mmc/mmc.h

+6 −0
Original line number Diff line number Diff line
@@ -280,6 +280,7 @@ struct _mmc_csd { 
#define EXT_CSD_RST_N_FUNCTION		162	/* R/W */

#define EXT_CSD_SANITIZE_START		165     /* W */

#define EXT_CSD_WR_REL_PARAM		166	/* RO */

#define EXT_CSD_BOOT_WP			173	/* R/W */

#define EXT_CSD_ERASE_GROUP_DEF		175	/* R/W */

#define EXT_CSD_PART_CONFIG		179	/* R/W */

#define EXT_CSD_ERASED_MEM_CONT		181	/* RO */
@@ -321,6 +322,11 @@ struct _mmc_csd { 


#define EXT_CSD_WR_REL_PARAM_EN		(1<<2)



#define EXT_CSD_BOOT_WP_B_PWR_WP_DIS	(0x40)

#define EXT_CSD_BOOT_WP_B_PERM_WP_DIS	(0x10)

#define EXT_CSD_BOOT_WP_B_PERM_WP_EN	(0x04)

#define EXT_CSD_BOOT_WP_B_PWR_WP_EN	(0x01)



#define EXT_CSD_PART_CONFIG_ACC_MASK	(0x7)

#define EXT_CSD_PART_CONFIG_ACC_BOOT0	(0x1)

#define EXT_CSD_PART_CONFIG_ACC_GP0	(0x4)