crypto: ecc - Export additional helper functions

Export the following additional ECC helper functions:
- ecc_alloc_point()
- ecc_free_point()
- vli_num_bits()
- ecc_point_is_zero()

This is done to allow future ECC device drivers to re-use existing code,
thus simplifying their implementation.

Functions are exported using EXPORT_SYMBOL() (instead of
EXPORT_SYMBOL_GPL()) to be consistent with the functions already
exported by crypto/ecc.c.

Exported functions are documented in include/crypto/internal/ecc.h.

Signed-off-by: Daniele Alessandrelli <[email protected]>
Signed-off-by: Herbert Xu <[email protected]>

crypto/ecc.c

@@ -81,7 +81,7 @@ static void ecc_free_digits_space(u64 *space)
 	kfree_sensitive(space);
 }
 
-static struct ecc_point *ecc_alloc_point(unsigned int ndigits)
+struct ecc_point *ecc_alloc_point(unsigned int ndigits)
 {
 	struct ecc_point *p = kmalloc(sizeof(*p), GFP_KERNEL);
 
@@ -106,8 +106,9 @@ static struct ecc_point *ecc_alloc_point(unsigned int ndigits)
 	kfree(p);
 	return NULL;
 }
+EXPORT_SYMBOL(ecc_alloc_point);
 
-static void ecc_free_point(struct ecc_point *p)
+void ecc_free_point(struct ecc_point *p)
 {
 	if (!p)
 		return;
@@ -116,6 +117,7 @@ static void ecc_free_point(struct ecc_point *p)
 	kfree_sensitive(p->y);
 	kfree_sensitive(p);
 }
+EXPORT_SYMBOL(ecc_free_point);
 
 static void vli_clear(u64 *vli, unsigned int ndigits)
 {
@@ -165,7 +167,7 @@ static unsigned int vli_num_digits(const u64 *vli, unsigned int ndigits)
 }
 
 /* Counts the number of bits required for vli. */
-static unsigned int vli_num_bits(const u64 *vli, unsigned int ndigits)
+unsigned int vli_num_bits(const u64 *vli, unsigned int ndigits)
 {
 	unsigned int i, num_digits;
 	u64 digit;
@@ -180,6 +182,7 @@ static unsigned int vli_num_bits(const u64 *vli, unsigned int ndigits)
 
 	return ((num_digits - 1) * 64 + i);
 }
+EXPORT_SYMBOL(vli_num_bits);
 
 /* Set dest from unaligned bit string src. */
 void vli_from_be64(u64 *dest, const void *src, unsigned int ndigits)
@@ -1062,11 +1065,12 @@ EXPORT_SYMBOL(vli_mod_inv);
 /* ------ Point operations ------ */
 
 /* Returns true if p_point is the point at infinity, false otherwise. */
-static bool ecc_point_is_zero(const struct ecc_point *point)
+bool ecc_point_is_zero(const struct ecc_point *point)
 {
 	return (vli_is_zero(point->x, point->ndigits) &&
 		vli_is_zero(point->y, point->ndigits));
 }
+EXPORT_SYMBOL(ecc_point_is_zero);
 
 /* Point multiplication algorithm using Montgomery's ladder with co-Z
  * coordinates. From https://eprint.iacr.org/2011/338.pdf

include/crypto/internal/ecc.h

@@ -225,6 +225,41 @@ void vli_mod_inv(u64 *result, const u64 *input, const u64 *mod,
 void vli_mod_mult_slow(u64 *result, const u64 *left, const u64 *right,
 		       const u64 *mod, unsigned int ndigits);
 
+/**
+ * vli_num_bits() - Counts the number of bits required for vli.
+ *
+ * @vli:		vli to check.
+ * @ndigits:		Length of the @vli
+ *
+ * Return: The number of bits required to represent @vli.
+ */
+unsigned int vli_num_bits(const u64 *vli, unsigned int ndigits);
+
+/**
+ * ecc_aloc_point() - Allocate ECC point.
+ *
+ * @ndigits:		Length of vlis in u64 qwords.
+ *
+ * Return: Pointer to the allocated point or NULL if allocation failed.
+ */
+struct ecc_point *ecc_alloc_point(unsigned int ndigits);
+
+/**
+ * ecc_free_point() - Free ECC point.
+ *
+ * @p:			The point to free.
+ */
+void ecc_free_point(struct ecc_point *p);
+
+/**
+ * ecc_point_is_zero() - Check if point is zero.
+ *
+ * @p:			Point to check for zero.
+ *
+ * Return: true if point is the point at infinity, false otherwise.
+ */
+bool ecc_point_is_zero(const struct ecc_point *point);
+
 /**
  * ecc_point_mult_shamir() - Add two points multiplied by scalars
  *
@@ -242,4 +277,5 @@ void ecc_point_mult_shamir(const struct ecc_point *result,
 			   const u64 *x, const struct ecc_point *p,
 			   const u64 *y, const struct ecc_point *q,
 			   const struct ecc_curve *curve);
+
 #endif