// SPDX-License-Identifier: GPL-2.0
/*
 * t10_pi.c - Functions for generating and verifying T10 Protection
 *            Information.
 */

#include <linux/t10-pi.h>
#include <linux/blk-integrity.h>
#include <linux/crc-t10dif.h>
#include <linux/crc64.h>
#include <net/checksum.h>
#include <linux/unaligned.h>
#include "blk.h"

struct blk_integrity_iter {
        void                    *prot_buf;
        void                    *data_buf;
        sector_t                seed;
        unsigned int            data_size;
        unsigned short          interval;
        const char              *disk_name;
};

static __be16 t10_pi_csum(__be16 csum, void *data, unsigned int len,
                unsigned char csum_type)
{
        if (csum_type == BLK_INTEGRITY_CSUM_IP)
                return (__force __be16)ip_compute_csum(data, len);
        return cpu_to_be16(crc_t10dif_update(be16_to_cpu(csum), data, len));
}

/*
 * Type 1 and Type 2 protection use the same format: 16 bit guard tag,
 * 16 bit app tag, 32 bit reference tag. Type 3 does not define the ref
 * tag.
 */
static void t10_pi_generate(struct blk_integrity_iter *iter,
                struct blk_integrity *bi)
{
        u8 offset = bi->pi_offset;
        unsigned int i;

        for (i = 0 ; i < iter->data_size ; i += iter->interval) {
                struct t10_pi_tuple *pi = iter->prot_buf + offset;

                pi->guard_tag = t10_pi_csum(0, iter->data_buf, iter->interval,
                                bi->csum_type);
                if (offset)
                        pi->guard_tag = t10_pi_csum(pi->guard_tag,
                                        iter->prot_buf, offset, bi->csum_type);
                pi->app_tag = 0;

                if (bi->flags & BLK_INTEGRITY_REF_TAG)
                        pi->ref_tag = cpu_to_be32(lower_32_bits(iter->seed));
                else
                        pi->ref_tag = 0;

                iter->data_buf += iter->interval;
                iter->prot_buf += bi->metadata_size;
                iter->seed++;
        }
}

static blk_status_t t10_pi_verify(struct blk_integrity_iter *iter,
                struct blk_integrity *bi)
{
        u8 offset = bi->pi_offset;
        unsigned int i;

        for (i = 0 ; i < iter->data_size ; i += iter->interval) {
                struct t10_pi_tuple *pi = iter->prot_buf + offset;
                __be16 csum;

                if (bi->flags & BLK_INTEGRITY_REF_TAG) {
                        if (pi->app_tag == T10_PI_APP_ESCAPE)
                                goto next;

                        if (be32_to_cpu(pi->ref_tag) !=
                            lower_32_bits(iter->seed)) {
                                pr_err("%s: ref tag error at location %llu " \
                                       "(rcvd %u)\n", iter->disk_name,
                                       (unsigned long long)
                                       iter->seed, be32_to_cpu(pi->ref_tag));
                                return BLK_STS_PROTECTION;
                        }
                } else {
                        if (pi->app_tag == T10_PI_APP_ESCAPE &&
                            pi->ref_tag == T10_PI_REF_ESCAPE)
                                goto next;
                }

                csum = t10_pi_csum(0, iter->data_buf, iter->interval,
                                bi->csum_type);
                if (offset)
                        csum = t10_pi_csum(csum, iter->prot_buf, offset,
                                        bi->csum_type);

                if (pi->guard_tag != csum) {
                        pr_err("%s: guard tag error at sector %llu " \
                               "(rcvd %04x, want %04x)\n", iter->disk_name,
                               (unsigned long long)iter->seed,
                               be16_to_cpu(pi->guard_tag), be16_to_cpu(csum));
                        return BLK_STS_PROTECTION;
                }

next:
                iter->data_buf += iter->interval;
                iter->prot_buf += bi->metadata_size;
                iter->seed++;
        }

        return BLK_STS_OK;
}

/**
 * t10_pi_type1_prepare - prepare PI prior submitting request to device
 * @rq:              request with PI that should be prepared
 *
 * For Type 1/Type 2, the virtual start sector is the one that was
 * originally submitted by the block layer for the ref_tag usage. Due to
 * partitioning, MD/DM cloning, etc. the actual physical start sector is
 * likely to be different. Remap protection information to match the
 * physical LBA.
 */
static void t10_pi_type1_prepare(struct request *rq)
{
        struct blk_integrity *bi = &rq->q->limits.integrity;
        const int tuple_sz = bi->metadata_size;
        u32 ref_tag = t10_pi_ref_tag(rq);
        u8 offset = bi->pi_offset;
        struct bio *bio;

        __rq_for_each_bio(bio, rq) {
                struct bio_integrity_payload *bip = bio_integrity(bio);
                u32 virt = bip_get_seed(bip) & 0xffffffff;
                struct bio_vec iv;
                struct bvec_iter iter;

                /* Already remapped? */
                if (bip->bip_flags & BIP_MAPPED_INTEGRITY)
                        break;

                bip_for_each_vec(iv, bip, iter) {
                        unsigned int j;
                        void *p;

                        p = bvec_kmap_local(&iv);
                        for (j = 0; j < iv.bv_len; j += tuple_sz) {
                                struct t10_pi_tuple *pi = p + offset;

                                if (be32_to_cpu(pi->ref_tag) == virt)
                                        pi->ref_tag = cpu_to_be32(ref_tag);
                                virt++;
                                ref_tag++;
                                p += tuple_sz;
                        }
                        kunmap_local(p);
                }

                bip->bip_flags |= BIP_MAPPED_INTEGRITY;
        }
}

/**
 * t10_pi_type1_complete - prepare PI prior returning request to the blk layer
 * @rq:              request with PI that should be prepared
 * @nr_bytes:        total bytes to prepare
 *
 * For Type 1/Type 2, the virtual start sector is the one that was
 * originally submitted by the block layer for the ref_tag usage. Due to
 * partitioning, MD/DM cloning, etc. the actual physical start sector is
 * likely to be different. Since the physical start sector was submitted
 * to the device, we should remap it back to virtual values expected by the
 * block layer.
 */
static void t10_pi_type1_complete(struct request *rq, unsigned int nr_bytes)
{
        struct blk_integrity *bi = &rq->q->limits.integrity;
        unsigned intervals = nr_bytes >> bi->interval_exp;
        const int tuple_sz = bi->metadata_size;
        u32 ref_tag = t10_pi_ref_tag(rq);
        u8 offset = bi->pi_offset;
        struct bio *bio;

        __rq_for_each_bio(bio, rq) {
                struct bio_integrity_payload *bip = bio_integrity(bio);
                u32 virt = bip_get_seed(bip) & 0xffffffff;
                struct bio_vec iv;
                struct bvec_iter iter;

                bip_for_each_vec(iv, bip, iter) {
                        unsigned int j;
                        void *p;

                        p = bvec_kmap_local(&iv);
                        for (j = 0; j < iv.bv_len && intervals; j += tuple_sz) {
                                struct t10_pi_tuple *pi = p + offset;

                                if (be32_to_cpu(pi->ref_tag) == ref_tag)
                                        pi->ref_tag = cpu_to_be32(virt);
                                virt++;
                                ref_tag++;
                                intervals--;
                                p += tuple_sz;
                        }
                        kunmap_local(p);
                }
        }
}

static __be64 ext_pi_crc64(u64 crc, void *data, unsigned int len)
{
        return cpu_to_be64(crc64_nvme(crc, data, len));
}

static void ext_pi_crc64_generate(struct blk_integrity_iter *iter,
                struct blk_integrity *bi)
{
        u8 offset = bi->pi_offset;
        unsigned int i;

        for (i = 0 ; i < iter->data_size ; i += iter->interval) {
                struct crc64_pi_tuple *pi = iter->prot_buf + offset;

                pi->guard_tag = ext_pi_crc64(0, iter->data_buf, iter->interval);
                if (offset)
                        pi->guard_tag = ext_pi_crc64(be64_to_cpu(pi->guard_tag),
                                        iter->prot_buf, offset);
                pi->app_tag = 0;

                if (bi->flags & BLK_INTEGRITY_REF_TAG)
                        put_unaligned_be48(iter->seed, pi->ref_tag);
                else
                        put_unaligned_be48(0ULL, pi->ref_tag);

                iter->data_buf += iter->interval;
                iter->prot_buf += bi->metadata_size;
                iter->seed++;
        }
}

static bool ext_pi_ref_escape(const u8 ref_tag[6])
{
        static const u8 ref_escape[6] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };

        return memcmp(ref_tag, ref_escape, sizeof(ref_escape)) == 0;
}

static blk_status_t ext_pi_crc64_verify(struct blk_integrity_iter *iter,
                struct blk_integrity *bi)
{
        u8 offset = bi->pi_offset;
        unsigned int i;

        for (i = 0; i < iter->data_size; i += iter->interval) {
                struct crc64_pi_tuple *pi = iter->prot_buf + offset;
                u64 ref, seed;
                __be64 csum;

                if (bi->flags & BLK_INTEGRITY_REF_TAG) {
                        if (pi->app_tag == T10_PI_APP_ESCAPE)
                                goto next;

                        ref = get_unaligned_be48(pi->ref_tag);
                        seed = lower_48_bits(iter->seed);
                        if (ref != seed) {
                                pr_err("%s: ref tag error at location %llu (rcvd %llu)\n",
                                        iter->disk_name, seed, ref);
                                return BLK_STS_PROTECTION;
                        }
                } else {
                        if (pi->app_tag == T10_PI_APP_ESCAPE &&
                            ext_pi_ref_escape(pi->ref_tag))
                                goto next;
                }

                csum = ext_pi_crc64(0, iter->data_buf, iter->interval);
                if (offset)
                        csum = ext_pi_crc64(be64_to_cpu(csum), iter->prot_buf,
                                            offset);

                if (pi->guard_tag != csum) {
                        pr_err("%s: guard tag error at sector %llu " \
                               "(rcvd %016llx, want %016llx)\n",
                                iter->disk_name, (unsigned long long)iter->seed,
                                be64_to_cpu(pi->guard_tag), be64_to_cpu(csum));
                        return BLK_STS_PROTECTION;
                }

next:
                iter->data_buf += iter->interval;
                iter->prot_buf += bi->metadata_size;
                iter->seed++;
        }

        return BLK_STS_OK;
}

static void ext_pi_type1_prepare(struct request *rq)
{
        struct blk_integrity *bi = &rq->q->limits.integrity;
        const int tuple_sz = bi->metadata_size;
        u64 ref_tag = ext_pi_ref_tag(rq);
        u8 offset = bi->pi_offset;
        struct bio *bio;

        __rq_for_each_bio(bio, rq) {
                struct bio_integrity_payload *bip = bio_integrity(bio);
                u64 virt = lower_48_bits(bip_get_seed(bip));
                struct bio_vec iv;
                struct bvec_iter iter;

                /* Already remapped? */
                if (bip->bip_flags & BIP_MAPPED_INTEGRITY)
                        break;

                bip_for_each_vec(iv, bip, iter) {
                        unsigned int j;
                        void *p;

                        p = bvec_kmap_local(&iv);
                        for (j = 0; j < iv.bv_len; j += tuple_sz) {
                                struct crc64_pi_tuple *pi = p +  offset;
                                u64 ref = get_unaligned_be48(pi->ref_tag);

                                if (ref == virt)
                                        put_unaligned_be48(ref_tag, pi->ref_tag);
                                virt++;
                                ref_tag++;
                                p += tuple_sz;
                        }
                        kunmap_local(p);
                }

                bip->bip_flags |= BIP_MAPPED_INTEGRITY;
        }
}

static void ext_pi_type1_complete(struct request *rq, unsigned int nr_bytes)
{
        struct blk_integrity *bi = &rq->q->limits.integrity;
        unsigned intervals = nr_bytes >> bi->interval_exp;
        const int tuple_sz = bi->metadata_size;
        u64 ref_tag = ext_pi_ref_tag(rq);
        u8 offset = bi->pi_offset;
        struct bio *bio;

        __rq_for_each_bio(bio, rq) {
                struct bio_integrity_payload *bip = bio_integrity(bio);
                u64 virt = lower_48_bits(bip_get_seed(bip));
                struct bio_vec iv;
                struct bvec_iter iter;

                bip_for_each_vec(iv, bip, iter) {
                        unsigned int j;
                        void *p;

                        p = bvec_kmap_local(&iv);
                        for (j = 0; j < iv.bv_len && intervals; j += tuple_sz) {
                                struct crc64_pi_tuple *pi = p + offset;
                                u64 ref = get_unaligned_be48(pi->ref_tag);

                                if (ref == ref_tag)
                                        put_unaligned_be48(virt, pi->ref_tag);
                                virt++;
                                ref_tag++;
                                intervals--;
                                p += tuple_sz;
                        }
                        kunmap_local(p);
                }
        }
}

void blk_integrity_generate(struct bio *bio)
{
        struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
        struct bio_integrity_payload *bip = bio_integrity(bio);
        struct blk_integrity_iter iter;
        struct bvec_iter bviter;
        struct bio_vec bv;

        iter.disk_name = bio->bi_bdev->bd_disk->disk_name;
        iter.interval = 1 << bi->interval_exp;
        iter.seed = bio->bi_iter.bi_sector;
        iter.prot_buf = bvec_virt(bip->bip_vec);
        bio_for_each_segment(bv, bio, bviter) {
                void *kaddr = bvec_kmap_local(&bv);

                iter.data_buf = kaddr;
                iter.data_size = bv.bv_len;
                switch (bi->csum_type) {
                case BLK_INTEGRITY_CSUM_CRC64:
                        ext_pi_crc64_generate(&iter, bi);
                        break;
                case BLK_INTEGRITY_CSUM_CRC:
                case BLK_INTEGRITY_CSUM_IP:
                        t10_pi_generate(&iter, bi);
                        break;
                default:
                        break;
                }
                kunmap_local(kaddr);
        }
}

void blk_integrity_verify_iter(struct bio *bio, struct bvec_iter *saved_iter)
{
        struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
        struct bio_integrity_payload *bip = bio_integrity(bio);
        struct blk_integrity_iter iter;
        struct bvec_iter bviter;
        struct bio_vec bv;

        /*
         * At the moment verify is called bi_iter has been advanced during split
         * and completion, so use the copy created during submission here.
         */
        iter.disk_name = bio->bi_bdev->bd_disk->disk_name;
        iter.interval = 1 << bi->interval_exp;
        iter.seed = saved_iter->bi_sector;
        iter.prot_buf = bvec_virt(bip->bip_vec);
        __bio_for_each_segment(bv, bio, bviter, *saved_iter) {
                void *kaddr = bvec_kmap_local(&bv);
                blk_status_t ret = BLK_STS_OK;

                iter.data_buf = kaddr;
                iter.data_size = bv.bv_len;
                switch (bi->csum_type) {
                case BLK_INTEGRITY_CSUM_CRC64:
                        ret = ext_pi_crc64_verify(&iter, bi);
                        break;
                case BLK_INTEGRITY_CSUM_CRC:
                case BLK_INTEGRITY_CSUM_IP:
                        ret = t10_pi_verify(&iter, bi);
                        break;
                default:
                        break;
                }
                kunmap_local(kaddr);

                if (ret) {
                        bio->bi_status = ret;
                        return;
                }
        }
}

void blk_integrity_prepare(struct request *rq)
{
        struct blk_integrity *bi = &rq->q->limits.integrity;

        if (!(bi->flags & BLK_INTEGRITY_REF_TAG))
                return;

        if (bi->csum_type == BLK_INTEGRITY_CSUM_CRC64)
                ext_pi_type1_prepare(rq);
        else
                t10_pi_type1_prepare(rq);
}

void blk_integrity_complete(struct request *rq, unsigned int nr_bytes)
{
        struct blk_integrity *bi = &rq->q->limits.integrity;

        if (!(bi->flags & BLK_INTEGRITY_REF_TAG))
                return;

        if (bi->csum_type == BLK_INTEGRITY_CSUM_CRC64)
                ext_pi_type1_complete(rq, nr_bytes);
        else
                t10_pi_type1_complete(rq, nr_bytes);
}