drivers/crypto/omap-crypto.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * OMAP Crypto driver common support routines.
   4  *
   5  * Copyright (c) 2017 Texas Instruments Incorporated
   6  *   Tero Kristo <t-kristo@ti.com>
   7  */
   8
   9 #include <linux/module.h>
  10 #include <linux/kernel.h>
  11 #include <linux/scatterlist.h>
  12 #include <crypto/scatterwalk.h>
  13
  14 #include "omap-crypto.h"
  15
  16 static int omap_crypto_copy_sg_lists(int total, int bs,
  17                                      struct scatterlist **sg,
  18                                      struct scatterlist *new_sg, u16 flags)
  19 {
  20         int n = sg_nents(*sg);
  21         struct scatterlist *tmp;
  22
  23         if (!(flags & OMAP_CRYPTO_FORCE_SINGLE_ENTRY)) {
  24                 new_sg = kmalloc_array(n, sizeof(*sg), GFP_KERNEL);
  25                 if (!new_sg)
  26                         return -ENOMEM;
  27
  28                 sg_init_table(new_sg, n);
  29         }
  30
  31         tmp = new_sg;
  32
  33         while (*sg && total) {
  34                 int len = (*sg)->length;
  35
  36                 if (total < len)
  37                         len = total;
  38
  39                 if (len > 0) {
  40                         total -= len;
  41                         sg_set_page(tmp, sg_page(*sg), len, (*sg)->offset);
  42                         if (total <= 0)
  43                                 sg_mark_end(tmp);
  44                         tmp = sg_next(tmp);
  45                 }
  46
  47                 *sg = sg_next(*sg);
  48         }
  49
  50         *sg = new_sg;
  51
  52         return 0;
  53 }
  54
  55 static int omap_crypto_copy_sgs(int total, int bs, struct scatterlist **sg,
  56                                 struct scatterlist *new_sg, u16 flags)
  57 {
  58         void *buf;
  59         int pages;
  60         int new_len;
  61
  62         new_len = ALIGN(total, bs);
  63         pages = get_order(new_len);
  64
  65         buf = (void *)__get_free_pages(GFP_ATOMIC, pages);
  66         if (!buf) {
  67                 pr_err("%s: Couldn't allocate pages for unaligned cases.\n",
  68                        __func__);
  69                 return -ENOMEM;
  70         }
  71
  72         if (flags & OMAP_CRYPTO_COPY_DATA) {
  73                 scatterwalk_map_and_copy(buf, *sg, 0, total, 0);
  74                 if (flags & OMAP_CRYPTO_ZERO_BUF)
  75                         memset(buf + total, 0, new_len - total);
  76         }
  77
  78         if (!(flags & OMAP_CRYPTO_FORCE_SINGLE_ENTRY))
  79                 sg_init_table(new_sg, 1);
  80
  81         sg_set_buf(new_sg, buf, new_len);
  82
  83         *sg = new_sg;
  84
  85         return 0;
  86 }
  87
  88 static int omap_crypto_check_sg(struct scatterlist *sg, int total, int bs,
  89                                 u16 flags)
  90 {
  91         int len = 0;
  92         int num_sg = 0;
  93
  94         if (!IS_ALIGNED(total, bs))
  95                 return OMAP_CRYPTO_NOT_ALIGNED;
  96
  97         while (sg) {
  98                 num_sg++;
  99
 100                 if (!IS_ALIGNED(sg->offset, 4))
 101                         return OMAP_CRYPTO_NOT_ALIGNED;
 102                 if (!IS_ALIGNED(sg->length, bs))
 103                         return OMAP_CRYPTO_NOT_ALIGNED;
 104 #ifdef CONFIG_ZONE_DMA
 105                 if (page_zonenum(sg_page(sg)) != ZONE_DMA)
 106                         return OMAP_CRYPTO_NOT_ALIGNED;
 107 #endif
 108
 109                 len += sg->length;
 110                 sg = sg_next(sg);
 111
 112                 if (len >= total)
 113                         break;
 114         }
 115
 116         if ((flags & OMAP_CRYPTO_FORCE_SINGLE_ENTRY) && num_sg > 1)
 117                 return OMAP_CRYPTO_NOT_ALIGNED;
 118
 119         if (len != total)
 120                 return OMAP_CRYPTO_BAD_DATA_LENGTH;
 121
 122         return 0;
 123 }
 124
 125 int omap_crypto_align_sg(struct scatterlist **sg, int total, int bs,
 126                          struct scatterlist *new_sg, u16 flags,
 127                          u8 flags_shift, unsigned long *dd_flags)
 128 {
 129         int ret;
 130
 131         *dd_flags &= ~(OMAP_CRYPTO_COPY_MASK << flags_shift);
 132
 133         if (flags & OMAP_CRYPTO_FORCE_COPY)
 134                 ret = OMAP_CRYPTO_NOT_ALIGNED;
 135         else
 136                 ret = omap_crypto_check_sg(*sg, total, bs, flags);
 137
 138         if (ret == OMAP_CRYPTO_NOT_ALIGNED) {
 139                 ret = omap_crypto_copy_sgs(total, bs, sg, new_sg, flags);
 140                 if (ret)
 141                         return ret;
 142                 *dd_flags |= OMAP_CRYPTO_DATA_COPIED << flags_shift;
 143         } else if (ret == OMAP_CRYPTO_BAD_DATA_LENGTH) {
 144                 ret = omap_crypto_copy_sg_lists(total, bs, sg, new_sg, flags);
 145                 if (ret)
 146                         return ret;
 147                 if (!(flags & OMAP_CRYPTO_FORCE_SINGLE_ENTRY))
 148                         *dd_flags |= OMAP_CRYPTO_SG_COPIED << flags_shift;
 149         } else if (flags & OMAP_CRYPTO_FORCE_SINGLE_ENTRY) {
 150                 sg_set_buf(new_sg, sg_virt(*sg), (*sg)->length);
 151         }
 152
 153         return 0;
 154 }
 155 EXPORT_SYMBOL_GPL(omap_crypto_align_sg);
 156
 157 static void omap_crypto_copy_data(struct scatterlist *src,
 158                                   struct scatterlist *dst,
 159                                   int offset, int len)
 160 {
 161         int amt;
 162         void *srcb, *dstb;
 163         int srco = 0, dsto = offset;
 164
 165         while (src && dst && len) {
 166                 if (srco >= src->length) {
 167                         srco -= src->length;
 168                         src = sg_next(src);
 169                         continue;
 170                 }
 171
 172                 if (dsto >= dst->length) {
 173                         dsto -= dst->length;
 174                         dst = sg_next(dst);
 175                         continue;
 176                 }
 177
 178                 amt = min(src->length - srco, dst->length - dsto);
 179                 amt = min(len, amt);
 180
 181                 srcb = sg_virt(src) + srco;
 182                 dstb = sg_virt(dst) + dsto;
 183
 184                 memcpy(dstb, srcb, amt);
 185
 186                 srco += amt;
 187                 dsto += amt;
 188                 len -= amt;
 189         }
 190 }
 191
 192 void omap_crypto_cleanup(struct scatterlist *sg, struct scatterlist *orig,
 193                          int offset, int len, u8 flags_shift,
 194                          unsigned long flags)
 195 {
 196         void *buf;
 197         int pages;
 198
 199         flags >>= flags_shift;
 200         flags &= OMAP_CRYPTO_COPY_MASK;
 201
 202         if (!flags)
 203                 return;
 204
 205         buf = sg_virt(sg);
 206         pages = get_order(len);
 207
 208         if (orig && (flags & OMAP_CRYPTO_COPY_MASK))
 209                 omap_crypto_copy_data(sg, orig, offset, len);
 210
 211         if (flags & OMAP_CRYPTO_DATA_COPIED)
 212                 free_pages((unsigned long)buf, pages);
 213         else if (flags & OMAP_CRYPTO_SG_COPIED)
 214                 kfree(sg);
 215 }
 216 EXPORT_SYMBOL_GPL(omap_crypto_cleanup);
 217
 218 MODULE_DESCRIPTION("OMAP crypto support library.");
 219 MODULE_LICENSE("GPL v2");
 220 MODULE_AUTHOR("Tero Kristo <t-kristo@ti.com>");