// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Cryptographic API.
 *
 * Support for VIA PadLock hardware crypto engine.
 *
 * Copyright (c) 2006  Michal Ludvig <michal@logix.cz>
 */

#include <crypto/internal/hash.h>
#include <crypto/padlock.h>
#include <crypto/sha.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/scatterlist.h>
#include <asm/cpu_device_id.h>
#include <asm/fpu/api.h>

struct padlock_sha_desc {
        struct shash_desc fallback;
};

struct padlock_sha_ctx {
        struct crypto_shash *fallback;
};

static int padlock_sha_init(struct shash_desc *desc)
{
        struct padlock_sha_desc *dctx = shash_desc_ctx(desc);
        struct padlock_sha_ctx *ctx = crypto_shash_ctx(desc->tfm);

        dctx->fallback.tfm = ctx->fallback;
        return crypto_shash_init(&dctx->fallback);
}

static int padlock_sha_update(struct shash_desc *desc,
                              const u8 *data, unsigned int length)
{
        struct padlock_sha_desc *dctx = shash_desc_ctx(desc);

        return crypto_shash_update(&dctx->fallback, data, length);
}

static int padlock_sha_export(struct shash_desc *desc, void *out)
{
        struct padlock_sha_desc *dctx = shash_desc_ctx(desc);

        return crypto_shash_export(&dctx->fallback, out);
}

static int padlock_sha_import(struct shash_desc *desc, const void *in)
{
        struct padlock_sha_desc *dctx = shash_desc_ctx(desc);
        struct padlock_sha_ctx *ctx = crypto_shash_ctx(desc->tfm);

        dctx->fallback.tfm = ctx->fallback;
        return crypto_shash_import(&dctx->fallback, in);
}

static inline void padlock_output_block(uint32_t *src,
                        uint32_t *dst, size_t count)
{
        while (count--)
                *dst++ = swab32(*src++);
}

static int padlock_sha1_finup(struct shash_desc *desc, const u8 *in,
                              unsigned int count, u8 *out)
{
        /* We can't store directly to *out as it may be unaligned. */
        /* BTW Don't reduce the buffer size below 128 Bytes!
         *     PadLock microcode needs it that big. */
        char buf[128 + PADLOCK_ALIGNMENT - STACK_ALIGN] __attribute__
                ((aligned(STACK_ALIGN)));
        char *result = PTR_ALIGN(&buf[0], PADLOCK_ALIGNMENT);
        struct padlock_sha_desc *dctx = shash_desc_ctx(desc);
        struct sha1_state state;
        unsigned int space;
        unsigned int leftover;
        int err;

        err = crypto_shash_export(&dctx->fallback, &state);
        if (err)
                goto out;

        if (state.count + count > ULONG_MAX)
                return crypto_shash_finup(&dctx->fallback, in, count, out);

        leftover = ((state.count - 1) & (SHA1_BLOCK_SIZE - 1)) + 1;
        space =  SHA1_BLOCK_SIZE - leftover;
        if (space) {
                if (count > space) {
                        err = crypto_shash_update(&dctx->fallback, in, space) ?:
                              crypto_shash_export(&dctx->fallback, &state);
                        if (err)
                                goto out;
                        count -= space;
                        in += space;
                } else {
                        memcpy(state.buffer + leftover, in, count);
                        in = state.buffer;
                        count += leftover;
                        state.count &= ~(SHA1_BLOCK_SIZE - 1);
                }
        }

        memcpy(result, &state.state, SHA1_DIGEST_SIZE);

        asm volatile (".byte 0xf3,0x0f,0xa6,0xc8" /* rep xsha1 */
                      : \
                      : "c"((unsigned long)state.count + count), \
                        "a"((unsigned long)state.count), \
                        "S"(in), "D"(result));

        padlock_output_block((uint32_t *)result, (uint32_t *)out, 5);

out:
        return err;
}

static int padlock_sha1_final(struct shash_desc *desc, u8 *out)
{
        u8 buf[4];

        return padlock_sha1_finup(desc, buf, 0, out);
}

static int padlock_sha256_finup(struct shash_desc *desc, const u8 *in,
                                unsigned int count, u8 *out)
{
        /* We can't store directly to *out as it may be unaligned. */
        /* BTW Don't reduce the buffer size below 128 Bytes!
         *     PadLock microcode needs it that big. */
        char buf[128 + PADLOCK_ALIGNMENT - STACK_ALIGN] __attribute__
                ((aligned(STACK_ALIGN)));
        char *result = PTR_ALIGN(&buf[0], PADLOCK_ALIGNMENT);
        struct padlock_sha_desc *dctx = shash_desc_ctx(desc);
        struct sha256_state state;
        unsigned int space;
        unsigned int leftover;
        int err;

        err = crypto_shash_export(&dctx->fallback, &state);
        if (err)
                goto out;

        if (state.count + count > ULONG_MAX)
                return crypto_shash_finup(&dctx->fallback, in, count, out);

        leftover = ((state.count - 1) & (SHA256_BLOCK_SIZE - 1)) + 1;
        space =  SHA256_BLOCK_SIZE - leftover;
        if (space) {
                if (count > space) {
                        err = crypto_shash_update(&dctx->fallback, in, space) ?:
                              crypto_shash_export(&dctx->fallback, &state);
                        if (err)
                                goto out;
                        count -= space;
                        in += space;
                } else {
                        memcpy(state.buf + leftover, in, count);
                        in = state.buf;
                        count += leftover;
                        state.count &= ~(SHA1_BLOCK_SIZE - 1);
                }
        }

        memcpy(result, &state.state, SHA256_DIGEST_SIZE);

        asm volatile (".byte 0xf3,0x0f,0xa6,0xd0" /* rep xsha256 */
                      : \
                      : "c"((unsigned long)state.count + count), \
                        "a"((unsigned long)state.count), \
                        "S"(in), "D"(result));

        padlock_output_block((uint32_t *)result, (uint32_t *)out, 8);

out:
        return err;
}

static int padlock_sha256_final(struct shash_desc *desc, u8 *out)
{
        u8 buf[4];

        return padlock_sha256_finup(desc, buf, 0, out);
}

static int padlock_init_tfm(struct crypto_shash *hash)
{
        const char *fallback_driver_name = crypto_shash_alg_name(hash);
        struct padlock_sha_ctx *ctx = crypto_shash_ctx(hash);
        struct crypto_shash *fallback_tfm;

        /* Allocate a fallback and abort if it failed. */
        fallback_tfm = crypto_alloc_shash(fallback_driver_name, 0,
                                          CRYPTO_ALG_NEED_FALLBACK);
        if (IS_ERR(fallback_tfm)) {
                printk(KERN_WARNING PFX "Fallback driver '%s' could not be loaded!\n",
                       fallback_driver_name);
                return PTR_ERR(fallback_tfm);
        }

        ctx->fallback = fallback_tfm;
        hash->descsize += crypto_shash_descsize(fallback_tfm);
        return 0;
}

static void padlock_exit_tfm(struct crypto_shash *hash)
{
        struct padlock_sha_ctx *ctx = crypto_shash_ctx(hash);

        crypto_free_shash(ctx->fallback);
}

static struct shash_alg sha1_alg = {
        .digestsize     =       SHA1_DIGEST_SIZE,
        .init           =       padlock_sha_init,
        .update         =       padlock_sha_update,
        .finup          =       padlock_sha1_finup,
        .final          =       padlock_sha1_final,
        .export         =       padlock_sha_export,
        .import         =       padlock_sha_import,
        .init_tfm       =       padlock_init_tfm,
        .exit_tfm       =       padlock_exit_tfm,
        .descsize       =       sizeof(struct padlock_sha_desc),
        .statesize      =       sizeof(struct sha1_state),
        .base           =       {
                .cra_name               =       "sha1",
                .cra_driver_name        =       "sha1-padlock",
                .cra_priority           =       PADLOCK_CRA_PRIORITY,
                .cra_flags              =       CRYPTO_ALG_NEED_FALLBACK,
                .cra_blocksize          =       SHA1_BLOCK_SIZE,
                .cra_ctxsize            =       sizeof(struct padlock_sha_ctx),
                .cra_module             =       THIS_MODULE,
        }
};

static struct shash_alg sha256_alg = {
        .digestsize     =       SHA256_DIGEST_SIZE,
        .init           =       padlock_sha_init,
        .update         =       padlock_sha_update,
        .finup          =       padlock_sha256_finup,
        .final          =       padlock_sha256_final,
        .export         =       padlock_sha_export,
        .import         =       padlock_sha_import,
        .init_tfm       =       padlock_init_tfm,
        .exit_tfm       =       padlock_exit_tfm,
        .descsize       =       sizeof(struct padlock_sha_desc),
        .statesize      =       sizeof(struct sha256_state),
        .base           =       {
                .cra_name               =       "sha256",
                .cra_driver_name        =       "sha256-padlock",
                .cra_priority           =       PADLOCK_CRA_PRIORITY,
                .cra_flags              =       CRYPTO_ALG_NEED_FALLBACK,
                .cra_blocksize          =       SHA256_BLOCK_SIZE,
                .cra_ctxsize            =       sizeof(struct padlock_sha_ctx),
                .cra_module             =       THIS_MODULE,
        }
};

/* Add two shash_alg instance for hardware-implemented *
* multiple-parts hash supported by VIA Nano Processor.*/
static int padlock_sha1_init_nano(struct shash_desc *desc)
{
        struct sha1_state *sctx = shash_desc_ctx(desc);

        *sctx = (struct sha1_state){
                .state = { SHA1_H0, SHA1_H1, SHA1_H2, SHA1_H3, SHA1_H4 },
        };

        return 0;
}

static int padlock_sha1_update_nano(struct shash_desc *desc,
                        const u8 *data, unsigned int len)
{
        struct sha1_state *sctx = shash_desc_ctx(desc);
        unsigned int partial, done;
        const u8 *src;
        /*The PHE require the out buffer must 128 bytes and 16-bytes aligned*/
        u8 buf[128 + PADLOCK_ALIGNMENT - STACK_ALIGN] __attribute__
                ((aligned(STACK_ALIGN)));
        u8 *dst = PTR_ALIGN(&buf[0], PADLOCK_ALIGNMENT);

        partial = sctx->count & 0x3f;
        sctx->count += len;
        done = 0;
        src = data;
        memcpy(dst, (u8 *)(sctx->state), SHA1_DIGEST_SIZE);

        if ((partial + len) >= SHA1_BLOCK_SIZE) {

                /* Append the bytes in state's buffer to a block to handle */
                if (partial) {
                        done = -partial;
                        memcpy(sctx->buffer + partial, data,
                                done + SHA1_BLOCK_SIZE);
                        src = sctx->buffer;
                        asm volatile (".byte 0xf3,0x0f,0xa6,0xc8"
                        : "+S"(src), "+D"(dst) \
                        : "a"((long)-1), "c"((unsigned long)1));
                        done += SHA1_BLOCK_SIZE;
                        src = data + done;
                }

                /* Process the left bytes from the input data */
                if (len - done >= SHA1_BLOCK_SIZE) {
                        asm volatile (".byte 0xf3,0x0f,0xa6,0xc8"
                        : "+S"(src), "+D"(dst)
                        : "a"((long)-1),
                        "c"((unsigned long)((len - done) / SHA1_BLOCK_SIZE)));
                        done += ((len - done) - (len - done) % SHA1_BLOCK_SIZE);
                        src = data + done;
                }
                partial = 0;
        }
        memcpy((u8 *)(sctx->state), dst, SHA1_DIGEST_SIZE);
        memcpy(sctx->buffer + partial, src, len - done);

        return 0;
}

static int padlock_sha1_final_nano(struct shash_desc *desc, u8 *out)
{
        struct sha1_state *state = (struct sha1_state *)shash_desc_ctx(desc);
        unsigned int partial, padlen;
        __be64 bits;
        static const u8 padding[64] = { 0x80, };

        bits = cpu_to_be64(state->count << 3);

        /* Pad out to 56 mod 64 */
        partial = state->count & 0x3f;
        padlen = (partial < 56) ? (56 - partial) : ((64+56) - partial);
        padlock_sha1_update_nano(desc, padding, padlen);

        /* Append length field bytes */
        padlock_sha1_update_nano(desc, (const u8 *)&bits, sizeof(bits));

        /* Swap to output */
        padlock_output_block((uint32_t *)(state->state), (uint32_t *)out, 5);

        return 0;
}

static int padlock_sha256_init_nano(struct shash_desc *desc)
{
        struct sha256_state *sctx = shash_desc_ctx(desc);

        *sctx = (struct sha256_state){
                .state = { SHA256_H0, SHA256_H1, SHA256_H2, SHA256_H3, \
                                SHA256_H4, SHA256_H5, SHA256_H6, SHA256_H7},
        };

        return 0;
}

static int padlock_sha256_update_nano(struct shash_desc *desc, const u8 *data,
                          unsigned int len)
{
        struct sha256_state *sctx = shash_desc_ctx(desc);
        unsigned int partial, done;
        const u8 *src;
        /*The PHE require the out buffer must 128 bytes and 16-bytes aligned*/
        u8 buf[128 + PADLOCK_ALIGNMENT - STACK_ALIGN] __attribute__
                ((aligned(STACK_ALIGN)));
        u8 *dst = PTR_ALIGN(&buf[0], PADLOCK_ALIGNMENT);

        partial = sctx->count & 0x3f;
        sctx->count += len;
        done = 0;
        src = data;
        memcpy(dst, (u8 *)(sctx->state), SHA256_DIGEST_SIZE);

        if ((partial + len) >= SHA256_BLOCK_SIZE) {

                /* Append the bytes in state's buffer to a block to handle */
                if (partial) {
                        done = -partial;
                        memcpy(sctx->buf + partial, data,
                                done + SHA256_BLOCK_SIZE);
                        src = sctx->buf;
                        asm volatile (".byte 0xf3,0x0f,0xa6,0xd0"
                        : "+S"(src), "+D"(dst)
                        : "a"((long)-1), "c"((unsigned long)1));
                        done += SHA256_BLOCK_SIZE;
                        src = data + done;
                }

                /* Process the left bytes from input data*/
                if (len - done >= SHA256_BLOCK_SIZE) {
                        asm volatile (".byte 0xf3,0x0f,0xa6,0xd0"
                        : "+S"(src), "+D"(dst)
                        : "a"((long)-1),
                        "c"((unsigned long)((len - done) / 64)));
                        done += ((len - done) - (len - done) % 64);
                        src = data + done;
                }
                partial = 0;
        }
        memcpy((u8 *)(sctx->state), dst, SHA256_DIGEST_SIZE);
        memcpy(sctx->buf + partial, src, len - done);

        return 0;
}

static int padlock_sha256_final_nano(struct shash_desc *desc, u8 *out)
{
        struct sha256_state *state =
                (struct sha256_state *)shash_desc_ctx(desc);
        unsigned int partial, padlen;
        __be64 bits;
        static const u8 padding[64] = { 0x80, };

        bits = cpu_to_be64(state->count << 3);

        /* Pad out to 56 mod 64 */
        partial = state->count & 0x3f;
        padlen = (partial < 56) ? (56 - partial) : ((64+56) - partial);
        padlock_sha256_update_nano(desc, padding, padlen);

        /* Append length field bytes */
        padlock_sha256_update_nano(desc, (const u8 *)&bits, sizeof(bits));

        /* Swap to output */
        padlock_output_block((uint32_t *)(state->state), (uint32_t *)out, 8);

        return 0;
}

static int padlock_sha_export_nano(struct shash_desc *desc,
                                void *out)
{
        int statesize = crypto_shash_statesize(desc->tfm);
        void *sctx = shash_desc_ctx(desc);

        memcpy(out, sctx, statesize);
        return 0;
}

static int padlock_sha_import_nano(struct shash_desc *desc,
                                const void *in)
{
        int statesize = crypto_shash_statesize(desc->tfm);
        void *sctx = shash_desc_ctx(desc);

        memcpy(sctx, in, statesize);
        return 0;
}

static struct shash_alg sha1_alg_nano = {
        .digestsize     =       SHA1_DIGEST_SIZE,
        .init           =       padlock_sha1_init_nano,
        .update         =       padlock_sha1_update_nano,
        .final          =       padlock_sha1_final_nano,
        .export         =       padlock_sha_export_nano,
        .import         =       padlock_sha_import_nano,
        .descsize       =       sizeof(struct sha1_state),
        .statesize      =       sizeof(struct sha1_state),
        .base           =       {
                .cra_name               =       "sha1",
                .cra_driver_name        =       "sha1-padlock-nano",
                .cra_priority           =       PADLOCK_CRA_PRIORITY,
                .cra_blocksize          =       SHA1_BLOCK_SIZE,
                .cra_module             =       THIS_MODULE,
        }
};

static struct shash_alg sha256_alg_nano = {
        .digestsize     =       SHA256_DIGEST_SIZE,
        .init           =       padlock_sha256_init_nano,
        .update         =       padlock_sha256_update_nano,
        .final          =       padlock_sha256_final_nano,
        .export         =       padlock_sha_export_nano,
        .import         =       padlock_sha_import_nano,
        .descsize       =       sizeof(struct sha256_state),
        .statesize      =       sizeof(struct sha256_state),
        .base           =       {
                .cra_name               =       "sha256",
                .cra_driver_name        =       "sha256-padlock-nano",
                .cra_priority           =       PADLOCK_CRA_PRIORITY,
                .cra_blocksize          =       SHA256_BLOCK_SIZE,
                .cra_module             =       THIS_MODULE,
        }
};

static const struct x86_cpu_id padlock_sha_ids[] = {
        X86_MATCH_FEATURE(X86_FEATURE_PHE, NULL),
        {}
};
MODULE_DEVICE_TABLE(x86cpu, padlock_sha_ids);

static int __init padlock_init(void)
{
        int rc = -ENODEV;
        struct cpuinfo_x86 *c = &cpu_data(0);
        struct shash_alg *sha1;
        struct shash_alg *sha256;

        if (!x86_match_cpu(padlock_sha_ids) || !boot_cpu_has(X86_FEATURE_PHE_EN))
                return -ENODEV;

        /* Register the newly added algorithm module if on *
        * VIA Nano processor, or else just do as before */
        if (c->x86_model < 0x0f) {
                sha1 = &sha1_alg;
                sha256 = &sha256_alg;
        } else {
                sha1 = &sha1_alg_nano;
                sha256 = &sha256_alg_nano;
        }

        rc = crypto_register_shash(sha1);
        if (rc)
                goto out;

        rc = crypto_register_shash(sha256);
        if (rc)
                goto out_unreg1;

        printk(KERN_NOTICE PFX "Using VIA PadLock ACE for SHA1/SHA256 algorithms.\n");

        return 0;

out_unreg1:
        crypto_unregister_shash(sha1);

out:
        printk(KERN_ERR PFX "VIA PadLock SHA1/SHA256 initialization failed.\n");
        return rc;
}

static void __exit padlock_fini(void)
{
        struct cpuinfo_x86 *c = &cpu_data(0);

        if (c->x86_model >= 0x0f) {
                crypto_unregister_shash(&sha1_alg_nano);
                crypto_unregister_shash(&sha256_alg_nano);
        } else {
                crypto_unregister_shash(&sha1_alg);
                crypto_unregister_shash(&sha256_alg);
        }
}

module_init(padlock_init);
module_exit(padlock_fini);

MODULE_DESCRIPTION("VIA PadLock SHA1/SHA256 algorithms support.");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Michal Ludvig");

MODULE_ALIAS_CRYPTO("sha1-all");
MODULE_ALIAS_CRYPTO("sha256-all");
MODULE_ALIAS_CRYPTO("sha1-padlock");
MODULE_ALIAS_CRYPTO("sha256-padlock");