lkdtm: Add Control Flow Integrity test

[linux/fpc-iii.git] / drivers / scsi / sd_zbc.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * SCSI Zoned Block commands
 *
 * Copyright (C) 2014-2015 SUSE Linux GmbH
 * Written by: Hannes Reinecke <hare@suse.de>
 * Modified by: Damien Le Moal <damien.lemoal@hgst.com>
 * Modified by: Shaun Tancheff <shaun.tancheff@seagate.com>
 */

#include <linux/blkdev.h>
#include <linux/vmalloc.h>
#include <linux/sched/mm.h>

#include <asm/unaligned.h>

#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>

#include "sd.h"

/**
 * sd_zbc_parse_report - Convert a zone descriptor to a struct blk_zone,
 * @sdkp: The disk the report originated from
 * @buf: Address of the report zone descriptor
 * @zone: the destination zone structure
 *
 * All LBA sized values are converted to 512B sectors unit.
 */
static void sd_zbc_parse_report(struct scsi_disk *sdkp, u8 *buf,
                                struct blk_zone *zone)
{
        struct scsi_device *sdp = sdkp->device;

        memset(zone, 0, sizeof(struct blk_zone));

        zone->type = buf[0] & 0x0f;
        zone->cond = (buf[1] >> 4) & 0xf;
        if (buf[1] & 0x01)
                zone->reset = 1;
        if (buf[1] & 0x02)
                zone->non_seq = 1;

        zone->len = logical_to_sectors(sdp, get_unaligned_be64(&buf[8]));
        zone->start = logical_to_sectors(sdp, get_unaligned_be64(&buf[16]));
        zone->wp = logical_to_sectors(sdp, get_unaligned_be64(&buf[24]));
        if (zone->type != ZBC_ZONE_TYPE_CONV &&
            zone->cond == ZBC_ZONE_COND_FULL)
                zone->wp = zone->start + zone->len;
}

/**
 * sd_zbc_do_report_zones - Issue a REPORT ZONES scsi command.
 * @sdkp: The target disk
 * @buf: vmalloc-ed buffer to use for the reply
 * @buflen: the buffer size
 * @lba: Start LBA of the report
 * @partial: Do partial report
 *
 * For internal use during device validation.
 * Using partial=true can significantly speed up execution of a report zones
 * command because the disk does not have to count all possible report matching
 * zones and will only report the count of zones fitting in the command reply
 * buffer.
 */
static int sd_zbc_do_report_zones(struct scsi_disk *sdkp, unsigned char *buf,
                                  unsigned int buflen, sector_t lba,
                                  bool partial)
{
        struct scsi_device *sdp = sdkp->device;
        const int timeout = sdp->request_queue->rq_timeout;
        struct scsi_sense_hdr sshdr;
        unsigned char cmd[16];
        unsigned int rep_len;
        int result;

        memset(cmd, 0, 16);
        cmd[0] = ZBC_IN;
        cmd[1] = ZI_REPORT_ZONES;
        put_unaligned_be64(lba, &cmd[2]);
        put_unaligned_be32(buflen, &cmd[10]);
        if (partial)
                cmd[14] = ZBC_REPORT_ZONE_PARTIAL;

        result = scsi_execute_req(sdp, cmd, DMA_FROM_DEVICE,
                                  buf, buflen, &sshdr,
                                  timeout, SD_MAX_RETRIES, NULL);
        if (result) {
                sd_printk(KERN_ERR, sdkp,
                          "REPORT ZONES lba %llu failed with %d/%d\n",
                          (unsigned long long)lba,
                          host_byte(result), driver_byte(result));
                return -EIO;
        }

        rep_len = get_unaligned_be32(&buf[0]);
        if (rep_len < 64) {
                sd_printk(KERN_ERR, sdkp,
                          "REPORT ZONES report invalid length %u\n",
                          rep_len);
                return -EIO;
        }

        return 0;
}

/*
 * Maximum number of zones to get with one report zones command.
 */
#define SD_ZBC_REPORT_MAX_ZONES         8192U

/**
 * Allocate a buffer for report zones reply.
 * @sdkp: The target disk
 * @nr_zones: Maximum number of zones to report
 * @buflen: Size of the buffer allocated
 *
 * Try to allocate a reply buffer for the number of requested zones.
 * The size of the buffer allocated may be smaller than requested to
 * satify the device constraint (max_hw_sectors, max_segments, etc).
 *
 * Return the address of the allocated buffer and update @buflen with
 * the size of the allocated buffer.
 */
static void *sd_zbc_alloc_report_buffer(struct scsi_disk *sdkp,
                                        unsigned int nr_zones, size_t *buflen)
{
        struct request_queue *q = sdkp->disk->queue;
        size_t bufsize;
        void *buf;

        /*
         * Report zone buffer size should be at most 64B times the number of
         * zones requested plus the 64B reply header, but should be at least
         * SECTOR_SIZE for ATA devices.
         * Make sure that this size does not exceed the hardware capabilities.
         * Furthermore, since the report zone command cannot be split, make
         * sure that the allocated buffer can always be mapped by limiting the
         * number of pages allocated to the HBA max segments limit.
         */
        nr_zones = min(nr_zones, SD_ZBC_REPORT_MAX_ZONES);
        bufsize = roundup((nr_zones + 1) * 64, 512);
        bufsize = min_t(size_t, bufsize,
                        queue_max_hw_sectors(q) << SECTOR_SHIFT);
        bufsize = min_t(size_t, bufsize, queue_max_segments(q) << PAGE_SHIFT);

        buf = vzalloc(bufsize);
        if (buf)
                *buflen = bufsize;

        return buf;
}

/**
 * sd_zbc_report_zones - Disk report zones operation.
 * @disk: The target disk
 * @sector: Start 512B sector of the report
 * @zones: Array of zone descriptors
 * @nr_zones: Number of descriptors in the array
 *
 * Execute a report zones command on the target disk.
 */
int sd_zbc_report_zones(struct gendisk *disk, sector_t sector,
                        struct blk_zone *zones, unsigned int *nr_zones)
{
        struct scsi_disk *sdkp = scsi_disk(disk);
        unsigned int i, nrz = *nr_zones;
        unsigned char *buf;
        size_t buflen = 0, offset = 0;
        int ret = 0;

        if (!sd_is_zoned(sdkp))
                /* Not a zoned device */
                return -EOPNOTSUPP;

        buf = sd_zbc_alloc_report_buffer(sdkp, nrz, &buflen);
        if (!buf)
                return -ENOMEM;

        ret = sd_zbc_do_report_zones(sdkp, buf, buflen,
                        sectors_to_logical(sdkp->device, sector), true);
        if (ret)
                goto out;

        nrz = min(nrz, get_unaligned_be32(&buf[0]) / 64);
        for (i = 0; i < nrz; i++) {
                offset += 64;
                sd_zbc_parse_report(sdkp, buf + offset, zones);
                zones++;
        }

        *nr_zones = nrz;

out:
        kvfree(buf);

        return ret;
}

/**
 * sd_zbc_zone_sectors - Get the device zone size in number of 512B sectors.
 * @sdkp: The target disk
 */
static inline sector_t sd_zbc_zone_sectors(struct scsi_disk *sdkp)
{
        return logical_to_sectors(sdkp->device, sdkp->zone_blocks);
}

/**
 * sd_zbc_setup_reset_cmnd - Prepare a RESET WRITE POINTER scsi command.
 * @cmd: the command to setup
 *
 * Called from sd_init_command() for a REQ_OP_ZONE_RESET request.
 */
blk_status_t sd_zbc_setup_reset_cmnd(struct scsi_cmnd *cmd)
{
        struct request *rq = cmd->request;
        struct scsi_disk *sdkp = scsi_disk(rq->rq_disk);
        sector_t sector = blk_rq_pos(rq);
        sector_t block = sectors_to_logical(sdkp->device, sector);

        if (!sd_is_zoned(sdkp))
                /* Not a zoned device */
                return BLK_STS_IOERR;

        if (sdkp->device->changed)
                return BLK_STS_IOERR;

        if (sector & (sd_zbc_zone_sectors(sdkp) - 1))
                /* Unaligned request */
                return BLK_STS_IOERR;

        cmd->cmd_len = 16;
        memset(cmd->cmnd, 0, cmd->cmd_len);
        cmd->cmnd[0] = ZBC_OUT;
        cmd->cmnd[1] = ZO_RESET_WRITE_POINTER;
        put_unaligned_be64(block, &cmd->cmnd[2]);

        rq->timeout = SD_TIMEOUT;
        cmd->sc_data_direction = DMA_NONE;
        cmd->transfersize = 0;
        cmd->allowed = 0;

        return BLK_STS_OK;
}

/**
 * sd_zbc_complete - ZBC command post processing.
 * @cmd: Completed command
 * @good_bytes: Command reply bytes
 * @sshdr: command sense header
 *
 * Called from sd_done(). Process report zones reply and handle reset zone
 * and write commands errors.
 */
void sd_zbc_complete(struct scsi_cmnd *cmd, unsigned int good_bytes,
                     struct scsi_sense_hdr *sshdr)
{
        int result = cmd->result;
        struct request *rq = cmd->request;

        switch (req_op(rq)) {
        case REQ_OP_ZONE_RESET:

                if (result &&
                    sshdr->sense_key == ILLEGAL_REQUEST &&
                    sshdr->asc == 0x24)
                        /*
                         * INVALID FIELD IN CDB error: reset of a conventional
                         * zone was attempted. Nothing to worry about, so be
                         * quiet about the error.
                         */
                        rq->rq_flags |= RQF_QUIET;
                break;

        case REQ_OP_WRITE:
        case REQ_OP_WRITE_ZEROES:
        case REQ_OP_WRITE_SAME:
                break;
        }
}

/**
 * sd_zbc_check_zoned_characteristics - Check zoned block device characteristics
 * @sdkp: Target disk
 * @buf: Buffer where to store the VPD page data
 *
 * Read VPD page B6, get information and check that reads are unconstrained.
 */
static int sd_zbc_check_zoned_characteristics(struct scsi_disk *sdkp,
                                              unsigned char *buf)
{

        if (scsi_get_vpd_page(sdkp->device, 0xb6, buf, 64)) {
                sd_printk(KERN_NOTICE, sdkp,
                          "Read zoned characteristics VPD page failed\n");
                return -ENODEV;
        }

        if (sdkp->device->type != TYPE_ZBC) {
                /* Host-aware */
                sdkp->urswrz = 1;
                sdkp->zones_optimal_open = get_unaligned_be32(&buf[8]);
                sdkp->zones_optimal_nonseq = get_unaligned_be32(&buf[12]);
                sdkp->zones_max_open = 0;
        } else {
                /* Host-managed */
                sdkp->urswrz = buf[4] & 1;
                sdkp->zones_optimal_open = 0;
                sdkp->zones_optimal_nonseq = 0;
                sdkp->zones_max_open = get_unaligned_be32(&buf[16]);
        }

        /*
         * Check for unconstrained reads: host-managed devices with
         * constrained reads (drives failing read after write pointer)
         * are not supported.
         */
        if (!sdkp->urswrz) {
                if (sdkp->first_scan)
                        sd_printk(KERN_NOTICE, sdkp,
                          "constrained reads devices are not supported\n");
                return -ENODEV;
        }

        return 0;
}

/**
 * sd_zbc_check_zones - Check the device capacity and zone sizes
 * @sdkp: Target disk
 *
 * Check that the device capacity as reported by READ CAPACITY matches the
 * max_lba value (plus one)of the report zones command reply. Also check that
 * all zones of the device have an equal size, only allowing the last zone of
 * the disk to have a smaller size (runt zone). The zone size must also be a
 * power of two.
 *
 * Returns the zone size in number of blocks upon success or an error code
 * upon failure.
 */
static int sd_zbc_check_zones(struct scsi_disk *sdkp, u32 *zblocks)
{
        size_t bufsize, buflen;
        unsigned int noio_flag;
        u64 zone_blocks = 0;
        sector_t max_lba, block = 0;
        unsigned char *buf;
        unsigned char *rec;
        int ret;
        u8 same;

        /* Do all memory allocations as if GFP_NOIO was specified */
        noio_flag = memalloc_noio_save();

        /* Get a buffer */
        buf = sd_zbc_alloc_report_buffer(sdkp, SD_ZBC_REPORT_MAX_ZONES,
                                         &bufsize);
        if (!buf) {
                ret = -ENOMEM;
                goto out;
        }

        /* Do a report zone to get max_lba and the same field */
        ret = sd_zbc_do_report_zones(sdkp, buf, bufsize, 0, false);
        if (ret)
                goto out_free;

        if (sdkp->rc_basis == 0) {
                /* The max_lba field is the capacity of this device */
                max_lba = get_unaligned_be64(&buf[8]);
                if (sdkp->capacity != max_lba + 1) {
                        if (sdkp->first_scan)
                                sd_printk(KERN_WARNING, sdkp,
                                        "Changing capacity from %llu to max LBA+1 %llu\n",
                                        (unsigned long long)sdkp->capacity,
                                        (unsigned long long)max_lba + 1);
                        sdkp->capacity = max_lba + 1;
                }
        }

        /*
         * Check same field: for any value other than 0, we know that all zones
         * have the same size.
         */
        same = buf[4] & 0x0f;
        if (same > 0) {
                rec = &buf[64];
                zone_blocks = get_unaligned_be64(&rec[8]);
                goto out;
        }

        /*
         * Check the size of all zones: all zones must be of
         * equal size, except the last zone which can be smaller
         * than other zones.
         */
        do {

                /* Parse REPORT ZONES header */
                buflen = min_t(size_t, get_unaligned_be32(&buf[0]) + 64,
                               bufsize);
                rec = buf + 64;

                /* Parse zone descriptors */
                while (rec < buf + buflen) {
                        u64 this_zone_blocks = get_unaligned_be64(&rec[8]);

                        if (zone_blocks == 0) {
                                zone_blocks = this_zone_blocks;
                        } else if (this_zone_blocks != zone_blocks &&
                                   (block + this_zone_blocks < sdkp->capacity
                                    || this_zone_blocks > zone_blocks)) {
                                zone_blocks = 0;
                                goto out;
                        }
                        block += this_zone_blocks;
                        rec += 64;
                }

                if (block < sdkp->capacity) {
                        ret = sd_zbc_do_report_zones(sdkp, buf, bufsize, block,
                                                     true);
                        if (ret)
                                goto out_free;
                }

        } while (block < sdkp->capacity);

out:
        if (!zone_blocks) {
                if (sdkp->first_scan)
                        sd_printk(KERN_NOTICE, sdkp,
                                  "Devices with non constant zone "
                                  "size are not supported\n");
                ret = -ENODEV;
        } else if (!is_power_of_2(zone_blocks)) {
                if (sdkp->first_scan)
                        sd_printk(KERN_NOTICE, sdkp,
                                  "Devices with non power of 2 zone "
                                  "size are not supported\n");
                ret = -ENODEV;
        } else if (logical_to_sectors(sdkp->device, zone_blocks) > UINT_MAX) {
                if (sdkp->first_scan)
                        sd_printk(KERN_NOTICE, sdkp,
                                  "Zone size too large\n");
                ret = -EFBIG;
        } else {
                *zblocks = zone_blocks;
                ret = 0;
        }

out_free:
        memalloc_noio_restore(noio_flag);
        kvfree(buf);

        return ret;
}

int sd_zbc_read_zones(struct scsi_disk *sdkp, unsigned char *buf)
{
        struct gendisk *disk = sdkp->disk;
        unsigned int nr_zones;
        u32 zone_blocks = 0;
        int ret;

        if (!sd_is_zoned(sdkp))
                /*
                 * Device managed or normal SCSI disk,
                 * no special handling required
                 */
                return 0;

        /* Check zoned block device characteristics (unconstrained reads) */
        ret = sd_zbc_check_zoned_characteristics(sdkp, buf);
        if (ret)
                goto err;

        /*
         * Check zone size: only devices with a constant zone size (except
         * an eventual last runt zone) that is a power of 2 are supported.
         */
        ret = sd_zbc_check_zones(sdkp, &zone_blocks);
        if (ret != 0)
                goto err;

        /* The drive satisfies the kernel restrictions: set it up */
        blk_queue_chunk_sectors(sdkp->disk->queue,
                        logical_to_sectors(sdkp->device, zone_blocks));
        nr_zones = round_up(sdkp->capacity, zone_blocks) >> ilog2(zone_blocks);

        /* READ16/WRITE16 is mandatory for ZBC disks */
        sdkp->device->use_16_for_rw = 1;
        sdkp->device->use_10_for_rw = 0;

        /*
         * Revalidate the disk zone bitmaps once the block device capacity is
         * set on the second revalidate execution during disk scan and if
         * something changed when executing a normal revalidate.
         */
        if (sdkp->first_scan) {
                sdkp->zone_blocks = zone_blocks;
                sdkp->nr_zones = nr_zones;
                return 0;
        }

        if (sdkp->zone_blocks != zone_blocks ||
            sdkp->nr_zones != nr_zones ||
            disk->queue->nr_zones != nr_zones) {
                ret = blk_revalidate_disk_zones(disk);
                if (ret != 0)
                        goto err;
                sdkp->zone_blocks = zone_blocks;
                sdkp->nr_zones = nr_zones;
        }

        return 0;

err:
        sdkp->capacity = 0;

        return ret;
}

void sd_zbc_print_zones(struct scsi_disk *sdkp)
{
        if (!sd_is_zoned(sdkp) || !sdkp->capacity)
                return;

        if (sdkp->capacity & (sdkp->zone_blocks - 1))
                sd_printk(KERN_NOTICE, sdkp,
                          "%u zones of %u logical blocks + 1 runt zone\n",
                          sdkp->nr_zones - 1,
                          sdkp->zone_blocks);
        else
                sd_printk(KERN_NOTICE, sdkp,
                          "%u zones of %u logical blocks\n",
                          sdkp->nr_zones,
                          sdkp->zone_blocks);
}