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-rw-r--r--lib/mpi/mpicoder.c161
1 files changed, 64 insertions, 97 deletions
diff --git a/lib/mpi/mpicoder.c b/lib/mpi/mpicoder.c
index ec533a6c77b5..747606f9e4a3 100644
--- a/lib/mpi/mpicoder.c
+++ b/lib/mpi/mpicoder.c
@@ -20,6 +20,8 @@
#include <linux/bitops.h>
#include <linux/count_zeros.h>
+#include <linux/byteorder/generic.h>
+#include <linux/string.h>
#include "mpi-internal.h"
#define MAX_EXTERN_MPI_BITS 16384
@@ -128,6 +130,23 @@ leave:
}
EXPORT_SYMBOL_GPL(mpi_read_from_buffer);
+static int count_lzeros(MPI a)
+{
+ mpi_limb_t alimb;
+ int i, lzeros = 0;
+
+ for (i = a->nlimbs - 1; i >= 0; i--) {
+ alimb = a->d[i];
+ if (alimb == 0) {
+ lzeros += sizeof(mpi_limb_t);
+ } else {
+ lzeros += count_leading_zeros(alimb) / 8;
+ break;
+ }
+ }
+ return lzeros;
+}
+
/**
* mpi_read_buffer() - read MPI to a bufer provided by user (msb first)
*
@@ -146,9 +165,15 @@ int mpi_read_buffer(MPI a, uint8_t *buf, unsigned buf_len, unsigned *nbytes,
int *sign)
{
uint8_t *p;
- mpi_limb_t alimb;
+#if BYTES_PER_MPI_LIMB == 4
+ __be32 alimb;
+#elif BYTES_PER_MPI_LIMB == 8
+ __be64 alimb;
+#else
+#error please implement for this limb size.
+#endif
unsigned int n = mpi_get_size(a);
- int i, lzeros = 0;
+ int i, lzeros;
if (!buf || !nbytes)
return -EINVAL;
@@ -156,14 +181,7 @@ int mpi_read_buffer(MPI a, uint8_t *buf, unsigned buf_len, unsigned *nbytes,
if (sign)
*sign = a->sign;
- p = (void *)&a->d[a->nlimbs] - 1;
-
- for (i = a->nlimbs * sizeof(alimb) - 1; i >= 0; i--, p--) {
- if (!*p)
- lzeros++;
- else
- break;
- }
+ lzeros = count_lzeros(a);
if (buf_len < n - lzeros) {
*nbytes = n - lzeros;
@@ -173,38 +191,19 @@ int mpi_read_buffer(MPI a, uint8_t *buf, unsigned buf_len, unsigned *nbytes,
p = buf;
*nbytes = n - lzeros;
- for (i = a->nlimbs - 1; i >= 0; i--) {
- alimb = a->d[i];
+ for (i = a->nlimbs - 1 - lzeros / BYTES_PER_MPI_LIMB,
+ lzeros %= BYTES_PER_MPI_LIMB;
+ i >= 0; i--) {
#if BYTES_PER_MPI_LIMB == 4
- *p++ = alimb >> 24;
- *p++ = alimb >> 16;
- *p++ = alimb >> 8;
- *p++ = alimb;
+ alimb = cpu_to_be32(a->d[i]);
#elif BYTES_PER_MPI_LIMB == 8
- *p++ = alimb >> 56;
- *p++ = alimb >> 48;
- *p++ = alimb >> 40;
- *p++ = alimb >> 32;
- *p++ = alimb >> 24;
- *p++ = alimb >> 16;
- *p++ = alimb >> 8;
- *p++ = alimb;
+ alimb = cpu_to_be64(a->d[i]);
#else
#error please implement for this limb size.
#endif
-
- if (lzeros > 0) {
- if (lzeros >= sizeof(alimb)) {
- p -= sizeof(alimb);
- } else {
- mpi_limb_t *limb1 = (void *)p - sizeof(alimb);
- mpi_limb_t *limb2 = (void *)p - sizeof(alimb)
- + lzeros;
- *limb1 = *limb2;
- p -= lzeros;
- }
- lzeros -= sizeof(alimb);
- }
+ memcpy(p, (u8 *)&alimb + lzeros, BYTES_PER_MPI_LIMB - lzeros);
+ p += BYTES_PER_MPI_LIMB - lzeros;
+ lzeros = 0;
}
return 0;
}
@@ -349,9 +348,15 @@ int mpi_write_to_sgl(MPI a, struct scatterlist *sgl, unsigned *nbytes,
int *sign)
{
u8 *p, *p2;
- mpi_limb_t alimb, alimb2;
+#if BYTES_PER_MPI_LIMB == 4
+ __be32 alimb;
+#elif BYTES_PER_MPI_LIMB == 8
+ __be64 alimb;
+#else
+#error please implement for this limb size.
+#endif
unsigned int n = mpi_get_size(a);
- int i, x, y = 0, lzeros = 0, buf_len;
+ int i, x, y = 0, lzeros, buf_len;
if (!nbytes)
return -EINVAL;
@@ -359,14 +364,7 @@ int mpi_write_to_sgl(MPI a, struct scatterlist *sgl, unsigned *nbytes,
if (sign)
*sign = a->sign;
- p = (void *)&a->d[a->nlimbs] - 1;
-
- for (i = a->nlimbs * sizeof(alimb) - 1; i >= 0; i--, p--) {
- if (!*p)
- lzeros++;
- else
- break;
- }
+ lzeros = count_lzeros(a);
if (*nbytes < n - lzeros) {
*nbytes = n - lzeros;
@@ -377,42 +375,22 @@ int mpi_write_to_sgl(MPI a, struct scatterlist *sgl, unsigned *nbytes,
buf_len = sgl->length;
p2 = sg_virt(sgl);
- for (i = a->nlimbs - 1; i >= 0; i--) {
- alimb = a->d[i];
- p = (u8 *)&alimb2;
+ for (i = a->nlimbs - 1 - lzeros / BYTES_PER_MPI_LIMB,
+ lzeros %= BYTES_PER_MPI_LIMB;
+ i >= 0; i--) {
#if BYTES_PER_MPI_LIMB == 4
- *p++ = alimb >> 24;
- *p++ = alimb >> 16;
- *p++ = alimb >> 8;
- *p++ = alimb;
+ alimb = cpu_to_be32(a->d[i]);
#elif BYTES_PER_MPI_LIMB == 8
- *p++ = alimb >> 56;
- *p++ = alimb >> 48;
- *p++ = alimb >> 40;
- *p++ = alimb >> 32;
- *p++ = alimb >> 24;
- *p++ = alimb >> 16;
- *p++ = alimb >> 8;
- *p++ = alimb;
+ alimb = cpu_to_be64(a->d[i]);
#else
#error please implement for this limb size.
#endif
- if (lzeros > 0) {
- if (lzeros >= sizeof(alimb)) {
- p -= sizeof(alimb);
- continue;
- } else {
- mpi_limb_t *limb1 = (void *)p - sizeof(alimb);
- mpi_limb_t *limb2 = (void *)p - sizeof(alimb)
- + lzeros;
- *limb1 = *limb2;
- p -= lzeros;
- y = lzeros;
- }
- lzeros -= sizeof(alimb);
+ if (lzeros) {
+ y = lzeros;
+ lzeros = 0;
}
- p = p - (sizeof(alimb) - y);
+ p = (u8 *)&alimb + y;
for (x = 0; x < sizeof(alimb) - y; x++) {
if (!buf_len) {
@@ -440,15 +418,15 @@ EXPORT_SYMBOL_GPL(mpi_write_to_sgl);
* a new MPI and reads the content of the sgl to the MPI.
*
* @sgl: scatterlist to read from
- * @len: number of bytes to read
+ * @nbytes: number of bytes to read
*
* Return: Pointer to a new MPI or NULL on error
*/
-MPI mpi_read_raw_from_sgl(struct scatterlist *sgl, unsigned int len)
+MPI mpi_read_raw_from_sgl(struct scatterlist *sgl, unsigned int nbytes)
{
struct scatterlist *sg;
int x, i, j, z, lzeros, ents;
- unsigned int nbits, nlimbs, nbytes;
+ unsigned int nbits, nlimbs;
mpi_limb_t a;
MPI val = NULL;
@@ -469,16 +447,12 @@ MPI mpi_read_raw_from_sgl(struct scatterlist *sgl, unsigned int len)
break;
ents--;
+ nbytes -= lzeros;
lzeros = 0;
}
sgl = sg;
-
- if (!ents)
- nbytes = 0;
- else
- nbytes = len - lzeros;
-
+ nbytes -= lzeros;
nbits = nbytes * 8;
if (nbits > MAX_EXTERN_MPI_BITS) {
pr_info("MPI: mpi too large (%u bits)\n", nbits);
@@ -486,9 +460,8 @@ MPI mpi_read_raw_from_sgl(struct scatterlist *sgl, unsigned int len)
}
if (nbytes > 0)
- nbits -= count_leading_zeros(*(u8 *)(sg_virt(sgl) + lzeros));
- else
- nbits = 0;
+ nbits -= count_leading_zeros(*(u8 *)(sg_virt(sgl) + lzeros)) -
+ (BITS_PER_LONG - 8);
nlimbs = DIV_ROUND_UP(nbytes, BYTES_PER_MPI_LIMB);
val = mpi_alloc(nlimbs);
@@ -504,19 +477,14 @@ MPI mpi_read_raw_from_sgl(struct scatterlist *sgl, unsigned int len)
j = nlimbs - 1;
a = 0;
- z = 0;
- x = BYTES_PER_MPI_LIMB - nbytes % BYTES_PER_MPI_LIMB;
- x %= BYTES_PER_MPI_LIMB;
+ z = BYTES_PER_MPI_LIMB - nbytes % BYTES_PER_MPI_LIMB;
+ z %= BYTES_PER_MPI_LIMB;
for_each_sg(sgl, sg, ents, i) {
const u8 *buffer = sg_virt(sg) + lzeros;
int len = sg->length - lzeros;
- int buf_shift = x;
-
- if (sg_is_last(sg) && (len % BYTES_PER_MPI_LIMB))
- len += BYTES_PER_MPI_LIMB - (len % BYTES_PER_MPI_LIMB);
- for (; x < len + buf_shift; x++) {
+ for (x = 0; x < len; x++) {
a <<= 8;
a |= *buffer++;
if (((z + x + 1) % BYTES_PER_MPI_LIMB) == 0) {
@@ -525,7 +493,6 @@ MPI mpi_read_raw_from_sgl(struct scatterlist *sgl, unsigned int len)
}
}
z += x;
- x = 0;
lzeros = 0;
}
return val;
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