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
Both boot partitions are locked by writing 1 to one of the files.
Signed-off-by: John Beckett <john.beckett@xxxxxxxxxxxxxx>
Signed-off-by: Johan Rudholm <johan.rudholm@xxxxxxxxxxxxxx>
---
Documentation/mmc/mmc-dev-parts.txt | 13 ++++
drivers/mmc/card/block.c | 127 ++++++++++++++++++++++++++++++++--
drivers/mmc/core/mmc.c | 14 +++-
include/linux/mmc/card.h | 10 +++-
include/linux/mmc/mmc.h | 6 ++
5 files changed, 159 insertions(+), 11 deletions(-)
diff --git a/Documentation/mmc/mmc-dev-parts.txt b/Documentation/mmc/mmc-dev-parts.txt
index 2db28b8..f08d078 100644
--- a/Documentation/mmc/mmc-dev-parts.txt
+++ b/Documentation/mmc/mmc-dev-parts.txt
@@ -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.
diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index a1cb21f..58ff85f 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -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 +167,75 @@ 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)
{
@@ -1339,7 +1410,8 @@ 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;
@@ -1364,11 +1436,12 @@ 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.
@@ -1462,7 +1535,8 @@ 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;
}
@@ -1471,13 +1545,14 @@ 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;
@@ -1510,7 +1585,8 @@ 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;
}
@@ -1539,9 +1615,16 @@ 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);
@@ -1570,6 +1653,7 @@ 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;
@@ -1579,7 +1663,34 @@ 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)
- del_gendisk(md->disk);
+ 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;
}
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index dbf421a..f19466f 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -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) {
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 415f2db..9d78778 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -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 */
@@ -184,6 +186,10 @@ 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)
};
/*
@@ -260,12 +266,14 @@ 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++;
}
diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
index 0e71356..665548e 100644
--- a/include/linux/mmc/mmc.h
+++ b/include/linux/mmc/mmc.h
@@ -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)
--
1.7.7
--
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