mtd: rawnand: Add support for secure regions in NAND memory
On a typical end product, a vendor may choose to secure some regions in the NAND memory which are supposed to stay intact between FW upgrades. The access to those regions will be blocked by a secure element like Trustzone. So the normal world software like Linux kernel should not touch these regions (including reading). The regions are declared using a NAND chip DT property, "secure-regions". So let's make use of this property in the raw NAND core and skip access to the secure regions present in a system. Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> Link: https://lore.kernel.org/linux-mtd/20210402150128.29128-4-manivannan.sadhasivam@linaro.org
This commit is contained in:
Manivannan Sadhasivam
Miquel Raynal
Родитель
ee590106c3
Коммит
13b8976827
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@ -278,11 +278,48 @@ static int nand_block_bad(struct nand_chip *chip, loff_t ofs)
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return 0;
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}
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/**
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* nand_region_is_secured() - Check if the region is secured
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* @chip: NAND chip object
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* @offset: Offset of the region to check
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* @size: Size of the region to check
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*
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* Checks if the region is secured by comparing the offset and size with the
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* list of secure regions obtained from DT. Returns true if the region is
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* secured else false.
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*/
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static bool nand_region_is_secured(struct nand_chip *chip, loff_t offset, u64 size)
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{
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int i;
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/* Skip touching the secure regions if present */
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for (i = 0; i < chip->nr_secure_regions; i++) {
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const struct nand_secure_region *region = &chip->secure_regions[i];
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if (offset + size <= region->offset ||
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offset >= region->offset + region->size)
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continue;
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pr_debug("%s: Region 0x%llx - 0x%llx is secured!",
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__func__, offset, offset + size);
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return true;
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}
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return false;
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}
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static int nand_isbad_bbm(struct nand_chip *chip, loff_t ofs)
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{
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struct mtd_info *mtd = nand_to_mtd(chip);
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if (chip->options & NAND_NO_BBM_QUIRK)
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return 0;
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/* Check if the region is secured */
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if (nand_region_is_secured(chip, ofs, mtd->erasesize))
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return -EIO;
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if (chip->legacy.block_bad)
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return chip->legacy.block_bad(chip, ofs);
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@ -397,6 +434,10 @@ static int nand_do_write_oob(struct nand_chip *chip, loff_t to,
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return -EINVAL;
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}
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/* Check if the region is secured */
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if (nand_region_is_secured(chip, to, ops->ooblen))
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return -EIO;
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chipnr = (int)(to >> chip->chip_shift);
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/*
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@ -3128,6 +3169,10 @@ static int nand_do_read_ops(struct nand_chip *chip, loff_t from,
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int retry_mode = 0;
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bool ecc_fail = false;
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/* Check if the region is secured */
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if (nand_region_is_secured(chip, from, readlen))
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return -EIO;
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chipnr = (int)(from >> chip->chip_shift);
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nand_select_target(chip, chipnr);
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@ -3459,6 +3504,10 @@ static int nand_do_read_oob(struct nand_chip *chip, loff_t from,
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pr_debug("%s: from = 0x%08Lx, len = %i\n",
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__func__, (unsigned long long)from, readlen);
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/* Check if the region is secured */
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if (nand_region_is_secured(chip, from, readlen))
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return -EIO;
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stats = mtd->ecc_stats;
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len = mtd_oobavail(mtd, ops);
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@ -3980,6 +4029,10 @@ static int nand_do_write_ops(struct nand_chip *chip, loff_t to,
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return -EINVAL;
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}
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/* Check if the region is secured */
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if (nand_region_is_secured(chip, to, writelen))
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return -EIO;
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column = to & (mtd->writesize - 1);
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chipnr = (int)(to >> chip->chip_shift);
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@ -4181,6 +4234,10 @@ int nand_erase_nand(struct nand_chip *chip, struct erase_info *instr,
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if (check_offs_len(chip, instr->addr, instr->len))
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return -EINVAL;
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/* Check if the region is secured */
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if (nand_region_is_secured(chip, instr->addr, instr->len))
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return -EIO;
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/* Grab the lock and see if the device is available */
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ret = nand_get_device(chip);
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if (ret)
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@ -4996,6 +5053,31 @@ static bool of_get_nand_on_flash_bbt(struct device_node *np)
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return of_property_read_bool(np, "nand-on-flash-bbt");
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}
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static int of_get_nand_secure_regions(struct nand_chip *chip)
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{
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struct device_node *dn = nand_get_flash_node(chip);
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int nr_elem, i, j;
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nr_elem = of_property_count_elems_of_size(dn, "secure-regions", sizeof(u64));
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if (!nr_elem)
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return 0;
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chip->nr_secure_regions = nr_elem / 2;
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chip->secure_regions = kcalloc(chip->nr_secure_regions, sizeof(*chip->secure_regions),
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GFP_KERNEL);
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if (!chip->secure_regions)
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return -ENOMEM;
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for (i = 0, j = 0; i < chip->nr_secure_regions; i++, j += 2) {
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of_property_read_u64_index(dn, "secure-regions", j,
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&chip->secure_regions[i].offset);
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of_property_read_u64_index(dn, "secure-regions", j + 1,
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&chip->secure_regions[i].size);
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}
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return 0;
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}
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static int rawnand_dt_init(struct nand_chip *chip)
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{
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struct nand_device *nand = mtd_to_nanddev(nand_to_mtd(chip));
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@ -5952,6 +6034,16 @@ static int nand_scan_tail(struct nand_chip *chip)
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goto err_free_interface_config;
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}
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/*
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* Look for secure regions in the NAND chip. These regions are supposed
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* to be protected by a secure element like Trustzone. So the read/write
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* accesses to these regions will be blocked in the runtime by this
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* driver.
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*/
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ret = of_get_nand_secure_regions(chip);
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if (ret)
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goto err_free_interface_config;
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/* Check, if we should skip the bad block table scan */
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if (chip->options & NAND_SKIP_BBTSCAN)
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return 0;
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@ -5959,10 +6051,13 @@ static int nand_scan_tail(struct nand_chip *chip)
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/* Build bad block table */
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ret = nand_create_bbt(chip);
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if (ret)
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goto err_free_interface_config;
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goto err_free_secure_regions;
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return 0;
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err_free_secure_regions:
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kfree(chip->secure_regions);
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err_free_interface_config:
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kfree(chip->best_interface_config);
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@ -6050,6 +6145,9 @@ void nand_cleanup(struct nand_chip *chip)
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nanddev_cleanup(&chip->base);
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/* Free secure regions data */
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kfree(chip->secure_regions);
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/* Free bad block table memory */
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kfree(chip->bbt);
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kfree(chip->data_buf);
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@ -1035,6 +1035,16 @@ struct nand_manufacturer {
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void *priv;
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};
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/**
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* struct nand_secure_region - NAND secure region structure
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* @offset: Offset of the start of the secure region
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* @size: Size of the secure region
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*/
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struct nand_secure_region {
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u64 offset;
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u64 size;
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};
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/**
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* struct nand_chip - NAND Private Flash Chip Data
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* @base: Inherit from the generic NAND device
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@ -1085,6 +1095,8 @@ struct nand_manufacturer {
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* NAND Controller drivers should not modify this value, but they're
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* allowed to read it.
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* @read_retries: The number of read retry modes supported
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* @secure_regions: Structure containing the secure regions info
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* @nr_secure_regions: Number of secure regions
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* @controller: The hardware controller structure which is shared among multiple
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* independent devices
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* @ecc: The ECC controller structure
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@ -1134,6 +1146,8 @@ struct nand_chip {
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unsigned int suspended : 1;
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int cur_cs;
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int read_retries;
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struct nand_secure_region *secure_regions;
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u8 nr_secure_regions;
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/* Externals */
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struct nand_controller *controller;
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