lib/mpi/mpi-internal.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /* mpi-internal.h  -  Internal to the Multi Precision Integers
   3  *      Copyright (C) 1994, 1996 Free Software Foundation, Inc.
   4  *      Copyright (C) 1998, 2000 Free Software Foundation, Inc.
   5  *
   6  * This file is part of GnuPG.
   7  *
   8  * Note: This code is heavily based on the GNU MP Library.
   9  *       Actually it's the same code with only minor changes in the
  10  *       way the data is stored; this is to support the abstraction
  11  *       of an optional secure memory allocation which may be used
  12  *       to avoid revealing of sensitive data due to paging etc.
  13  *       The GNU MP Library itself is published under the LGPL;
  14  *       however I decided to publish this code under the plain GPL.
  15  */
  16
  17 #ifndef G10_MPI_INTERNAL_H
  18 #define G10_MPI_INTERNAL_H
  19
  20 #include <linux/module.h>
  21 #include <linux/kernel.h>
  22 #include <linux/slab.h>
  23 #include <linux/string.h>
  24 #include <linux/mpi.h>
  25 #include <linux/errno.h>
  26
  27 #define log_debug printk
  28 #define log_bug printk
  29
  30 #define assert(x) \
  31         do { \
  32                 if (!x) \
  33                         log_bug("failed assertion\n"); \
  34         } while (0);
  35
  36 /* If KARATSUBA_THRESHOLD is not already defined, define it to a
  37  * value which is good on most machines.  */
  38
  39 /* tested 4, 16, 32 and 64, where 16 gave the best performance when
  40  * checking a 768 and a 1024 bit ElGamal signature.
  41  * (wk 22.12.97) */
  42 #ifndef KARATSUBA_THRESHOLD
  43 #define KARATSUBA_THRESHOLD 16
  44 #endif
  45
  46 /* The code can't handle KARATSUBA_THRESHOLD smaller than 2.  */
  47 #if KARATSUBA_THRESHOLD < 2
  48 #undef KARATSUBA_THRESHOLD
  49 #define KARATSUBA_THRESHOLD 2
  50 #endif
  51
  52 typedef mpi_limb_t *mpi_ptr_t;  /* pointer to a limb */
  53 typedef int mpi_size_t;         /* (must be a signed type) */
  54
  55 #define RESIZE_IF_NEEDED(a, b)                  \
  56         do {                                    \
  57                 if ((a)->alloced < (b))         \
  58                         mpi_resize((a), (b));   \
  59         } while (0)
  60
  61 /* Copy N limbs from S to D.  */
  62 #define MPN_COPY(d, s, n) \
  63         do {                                    \
  64                 mpi_size_t _i;                  \
  65                 for (_i = 0; _i < (n); _i++)    \
  66                         (d)[_i] = (s)[_i];      \
  67         } while (0)
  68
  69 #define MPN_COPY_INCR(d, s, n)          \
  70         do {                                    \
  71                 mpi_size_t _i;                  \
  72                 for (_i = 0; _i < (n); _i++)    \
  73                         (d)[_i] = (s)[_i];      \
  74         } while (0)
  75
  76
  77 #define MPN_COPY_DECR(d, s, n) \
  78         do {                                    \
  79                 mpi_size_t _i;                  \
  80                 for (_i = (n)-1; _i >= 0; _i--) \
  81                         (d)[_i] = (s)[_i];      \
  82         } while (0)
  83
  84 /* Zero N limbs at D */
  85 #define MPN_ZERO(d, n) \
  86         do {                                    \
  87                 int  _i;                        \
  88                 for (_i = 0; _i < (n); _i++)    \
  89                         (d)[_i] = 0;            \
  90         } while (0)
  91
  92 #define MPN_NORMALIZE(d, n)  \
  93         do {                                    \
  94                 while ((n) > 0) {               \
  95                         if ((d)[(n)-1])         \
  96                                 break;          \
  97                         (n)--;                  \
  98                 }                               \
  99         } while (0)
 100
 101 #define MPN_MUL_N_RECURSE(prodp, up, vp, size, tspace) \
 102         do {                                                    \
 103                 if ((size) < KARATSUBA_THRESHOLD)               \
 104                         mul_n_basecase(prodp, up, vp, size);    \
 105                 else                                            \
 106                         mul_n(prodp, up, vp, size, tspace);     \
 107         } while (0);
 108
 109 /* Divide the two-limb number in (NH,,NL) by D, with DI being the largest
 110  * limb not larger than (2**(2*BITS_PER_MP_LIMB))/D - (2**BITS_PER_MP_LIMB).
 111  * If this would yield overflow, DI should be the largest possible number
 112  * (i.e., only ones).  For correct operation, the most significant bit of D
 113  * has to be set.  Put the quotient in Q and the remainder in R.
 114  */
 115 #define UDIV_QRNND_PREINV(q, r, nh, nl, d, di)                          \
 116         do {                                                            \
 117                 mpi_limb_t _ql __maybe_unused;                          \
 118                 mpi_limb_t _q, _r;                                      \
 119                 mpi_limb_t _xh, _xl;                                    \
 120                 umul_ppmm(_q, _ql, (nh), (di));                         \
 121                 _q += (nh);     /* DI is 2**BITS_PER_MPI_LIMB too small */ \
 122                 umul_ppmm(_xh, _xl, _q, (d));                           \
 123                 sub_ddmmss(_xh, _r, (nh), (nl), _xh, _xl);              \
 124                 if (_xh) {                                              \
 125                         sub_ddmmss(_xh, _r, _xh, _r, 0, (d));           \
 126                         _q++;                                           \
 127                         if (_xh) {                                      \
 128                                 sub_ddmmss(_xh, _r, _xh, _r, 0, (d));   \
 129                                 _q++;                                   \
 130                         }                                               \
 131                 }                                                       \
 132                 if (_r >= (d)) {                                        \
 133                         _r -= (d);                                      \
 134                         _q++;                                           \
 135                 }                                                       \
 136                 (r) = _r;                                               \
 137                 (q) = _q;                                               \
 138         } while (0)
 139
 140
 141 /*-- mpiutil.c --*/
 142 mpi_ptr_t mpi_alloc_limb_space(unsigned nlimbs);
 143 void mpi_free_limb_space(mpi_ptr_t a);
 144 void mpi_assign_limb_space(MPI a, mpi_ptr_t ap, unsigned nlimbs);
 145
 146 static inline mpi_limb_t mpihelp_add_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
 147                          mpi_size_t s1_size, mpi_limb_t s2_limb);
 148 mpi_limb_t mpihelp_add_n(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
 149                          mpi_ptr_t s2_ptr, mpi_size_t size);
 150 static inline mpi_limb_t mpihelp_add(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size,
 151                        mpi_ptr_t s2_ptr, mpi_size_t s2_size);
 152
 153 static inline mpi_limb_t mpihelp_sub_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
 154                          mpi_size_t s1_size, mpi_limb_t s2_limb);
 155 mpi_limb_t mpihelp_sub_n(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
 156                          mpi_ptr_t s2_ptr, mpi_size_t size);
 157 static inline mpi_limb_t mpihelp_sub(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size,
 158                        mpi_ptr_t s2_ptr, mpi_size_t s2_size);
 159
 160 /*-- mpih-cmp.c --*/
 161 int mpihelp_cmp(mpi_ptr_t op1_ptr, mpi_ptr_t op2_ptr, mpi_size_t size);
 162
 163 /*-- mpih-mul.c --*/
 164
 165 struct karatsuba_ctx {
 166         struct karatsuba_ctx *next;
 167         mpi_ptr_t tspace;
 168         mpi_size_t tspace_size;
 169         mpi_ptr_t tp;
 170         mpi_size_t tp_size;
 171 };
 172
 173 void mpihelp_release_karatsuba_ctx(struct karatsuba_ctx *ctx);
 174
 175 mpi_limb_t mpihelp_addmul_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
 176                             mpi_size_t s1_size, mpi_limb_t s2_limb);
 177 mpi_limb_t mpihelp_submul_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
 178                             mpi_size_t s1_size, mpi_limb_t s2_limb);
 179 int mpihelp_mul(mpi_ptr_t prodp, mpi_ptr_t up, mpi_size_t usize,
 180                 mpi_ptr_t vp, mpi_size_t vsize, mpi_limb_t *_result);
 181 void mpih_sqr_n_basecase(mpi_ptr_t prodp, mpi_ptr_t up, mpi_size_t size);
 182 void mpih_sqr_n(mpi_ptr_t prodp, mpi_ptr_t up, mpi_size_t size,
 183                 mpi_ptr_t tspace);
 184 void mpihelp_mul_n(mpi_ptr_t prodp,
 185                 mpi_ptr_t up, mpi_ptr_t vp, mpi_size_t size);
 186
 187 int mpihelp_mul_karatsuba_case(mpi_ptr_t prodp,
 188                                mpi_ptr_t up, mpi_size_t usize,
 189                                mpi_ptr_t vp, mpi_size_t vsize,
 190                                struct karatsuba_ctx *ctx);
 191
 192 /*-- generic_mpih-mul1.c --*/
 193 mpi_limb_t mpihelp_mul_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
 194                          mpi_size_t s1_size, mpi_limb_t s2_limb);
 195
 196 /*-- mpih-div.c --*/
 197 mpi_limb_t mpihelp_mod_1(mpi_ptr_t dividend_ptr, mpi_size_t dividend_size,
 198                          mpi_limb_t divisor_limb);
 199 mpi_limb_t mpihelp_divrem(mpi_ptr_t qp, mpi_size_t qextra_limbs,
 200                           mpi_ptr_t np, mpi_size_t nsize,
 201                           mpi_ptr_t dp, mpi_size_t dsize);
 202 mpi_limb_t mpihelp_divmod_1(mpi_ptr_t quot_ptr,
 203                             mpi_ptr_t dividend_ptr, mpi_size_t dividend_size,
 204                             mpi_limb_t divisor_limb);
 205
 206 /*-- generic_mpih-[lr]shift.c --*/
 207 mpi_limb_t mpihelp_lshift(mpi_ptr_t wp, mpi_ptr_t up, mpi_size_t usize,
 208                           unsigned cnt);
 209 mpi_limb_t mpihelp_rshift(mpi_ptr_t wp, mpi_ptr_t up, mpi_size_t usize,
 210                           unsigned cnt);
 211
 212 /* Define stuff for longlong.h.  */
 213 #define W_TYPE_SIZE BITS_PER_MPI_LIMB
 214 typedef mpi_limb_t UWtype;
 215 typedef unsigned int UHWtype;
 216 #if defined(__GNUC__)
 217 typedef unsigned int UQItype __attribute__ ((mode(QI)));
 218 typedef int SItype __attribute__ ((mode(SI)));
 219 typedef unsigned int USItype __attribute__ ((mode(SI)));
 220 typedef int DItype __attribute__ ((mode(DI)));
 221 typedef unsigned int UDItype __attribute__ ((mode(DI)));
 222 #else
 223 typedef unsigned char UQItype;
 224 typedef long SItype;
 225 typedef unsigned long USItype;
 226 #endif
 227
 228 #ifdef __GNUC__
 229 #include "mpi-inline.h"
 230 #endif
 231
 232 #endif /*G10_MPI_INTERNAL_H */