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  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
 52typedef mpi_limb_t *mpi_ptr_t;	/* pointer to a limb */
 53typedef int mpi_size_t;		/* (must be a signed type) */
 54
 55static inline int RESIZE_IF_NEEDED(MPI a, unsigned b)
 56{
 57	if (a->alloced < b)
 58		return mpi_resize(a, b);
 59	return 0;
 60}
 61
 62/* Copy N limbs from S to D.  */
 63#define MPN_COPY(d, s, n) \
 64	do {					\
 65		mpi_size_t _i;			\
 66		for (_i = 0; _i < (n); _i++)	\
 67			(d)[_i] = (s)[_i];	\
 68	} while (0)
 69
 70#define MPN_COPY_DECR(d, s, n) \
 71	do {					\
 72		mpi_size_t _i;			\
 73		for (_i = (n)-1; _i >= 0; _i--) \
 74			(d)[_i] = (s)[_i];	\
 75	} while (0)
 76
 77/* Zero N limbs at D */
 78#define MPN_ZERO(d, n) \
 79	do {					\
 80		int  _i;			\
 81		for (_i = 0; _i < (n); _i++)	\
 82			(d)[_i] = 0;		\
 83	} while (0)
 84
 85#define MPN_NORMALIZE(d, n)  \
 86	do {					\
 87		while ((n) > 0) {		\
 88			if ((d)[(n)-1])		\
 89				break;		\
 90			(n)--;			\
 91		}				\
 92	} while (0)
 93
 94#define MPN_MUL_N_RECURSE(prodp, up, vp, size, tspace) \
 95	do {							\
 96		if ((size) < KARATSUBA_THRESHOLD)		\
 97			mul_n_basecase(prodp, up, vp, size);	\
 98		else						\
 99			mul_n(prodp, up, vp, size, tspace);	\
100	} while (0);
101
102/* Divide the two-limb number in (NH,,NL) by D, with DI being the largest
103 * limb not larger than (2**(2*BITS_PER_MP_LIMB))/D - (2**BITS_PER_MP_LIMB).
104 * If this would yield overflow, DI should be the largest possible number
105 * (i.e., only ones).  For correct operation, the most significant bit of D
106 * has to be set.  Put the quotient in Q and the remainder in R.
107 */
108#define UDIV_QRNND_PREINV(q, r, nh, nl, d, di)				\
109	do {								\
110		mpi_limb_t _ql __maybe_unused;				\
111		mpi_limb_t _q, _r;					\
112		mpi_limb_t _xh, _xl;					\
113		umul_ppmm(_q, _ql, (nh), (di));				\
114		_q += (nh);	/* DI is 2**BITS_PER_MPI_LIMB too small */ \
115		umul_ppmm(_xh, _xl, _q, (d));				\
116		sub_ddmmss(_xh, _r, (nh), (nl), _xh, _xl);		\
117		if (_xh) {						\
118			sub_ddmmss(_xh, _r, _xh, _r, 0, (d));		\
119			_q++;						\
120			if (_xh) {					\
121				sub_ddmmss(_xh, _r, _xh, _r, 0, (d));	\
122				_q++;					\
123			}						\
124		}							\
125		if (_r >= (d)) {					\
126			_r -= (d);					\
127			_q++;						\
128		}							\
129		(r) = _r;						\
130		(q) = _q;						\
131	} while (0)
132
133
134/*-- mpiutil.c --*/
135mpi_ptr_t mpi_alloc_limb_space(unsigned nlimbs);
136void mpi_free_limb_space(mpi_ptr_t a);
137void mpi_assign_limb_space(MPI a, mpi_ptr_t ap, unsigned nlimbs);
138
139static inline mpi_limb_t mpihelp_add_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
140			 mpi_size_t s1_size, mpi_limb_t s2_limb);
141mpi_limb_t mpihelp_add_n(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
142			 mpi_ptr_t s2_ptr, mpi_size_t size);
143static inline mpi_limb_t mpihelp_add(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size,
144		       mpi_ptr_t s2_ptr, mpi_size_t s2_size);
145
146static inline mpi_limb_t mpihelp_sub_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
147			 mpi_size_t s1_size, mpi_limb_t s2_limb);
148mpi_limb_t mpihelp_sub_n(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
149			 mpi_ptr_t s2_ptr, mpi_size_t size);
150static inline mpi_limb_t mpihelp_sub(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/*-- mpih-cmp.c --*/
154int mpihelp_cmp(mpi_ptr_t op1_ptr, mpi_ptr_t op2_ptr, mpi_size_t size);
155
156/*-- mpih-mul.c --*/
157
158struct karatsuba_ctx {
159	struct karatsuba_ctx *next;
160	mpi_ptr_t tspace;
161	mpi_size_t tspace_size;
162	mpi_ptr_t tp;
163	mpi_size_t tp_size;
164};
165
166void mpihelp_release_karatsuba_ctx(struct karatsuba_ctx *ctx);
167
168mpi_limb_t mpihelp_addmul_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
169			    mpi_size_t s1_size, mpi_limb_t s2_limb);
170mpi_limb_t mpihelp_submul_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
171			    mpi_size_t s1_size, mpi_limb_t s2_limb);
172int mpihelp_mul(mpi_ptr_t prodp, mpi_ptr_t up, mpi_size_t usize,
173		mpi_ptr_t vp, mpi_size_t vsize, mpi_limb_t *_result);
174void mpih_sqr_n_basecase(mpi_ptr_t prodp, mpi_ptr_t up, mpi_size_t size);
175void mpih_sqr_n(mpi_ptr_t prodp, mpi_ptr_t up, mpi_size_t size,
176		mpi_ptr_t tspace);
177
178int mpihelp_mul_karatsuba_case(mpi_ptr_t prodp,
179			       mpi_ptr_t up, mpi_size_t usize,
180			       mpi_ptr_t vp, mpi_size_t vsize,
181			       struct karatsuba_ctx *ctx);
182
183/*-- generic_mpih-mul1.c --*/
184mpi_limb_t mpihelp_mul_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
185			 mpi_size_t s1_size, mpi_limb_t s2_limb);
186
187/*-- mpih-div.c --*/
188mpi_limb_t mpihelp_mod_1(mpi_ptr_t dividend_ptr, mpi_size_t dividend_size,
189			 mpi_limb_t divisor_limb);
190mpi_limb_t mpihelp_divrem(mpi_ptr_t qp, mpi_size_t qextra_limbs,
191			  mpi_ptr_t np, mpi_size_t nsize,
192			  mpi_ptr_t dp, mpi_size_t dsize);
193mpi_limb_t mpihelp_divmod_1(mpi_ptr_t quot_ptr,
194			    mpi_ptr_t dividend_ptr, mpi_size_t dividend_size,
195			    mpi_limb_t divisor_limb);
196
197/*-- generic_mpih-[lr]shift.c --*/
198mpi_limb_t mpihelp_lshift(mpi_ptr_t wp, mpi_ptr_t up, mpi_size_t usize,
199			  unsigned cnt);
200mpi_limb_t mpihelp_rshift(mpi_ptr_t wp, mpi_ptr_t up, mpi_size_t usize,
201			  unsigned cnt);
202
203/* Define stuff for longlong.h.  */
204#define W_TYPE_SIZE BITS_PER_MPI_LIMB
205typedef mpi_limb_t UWtype;
206typedef unsigned int UHWtype;
207#if defined(__GNUC__)
208typedef unsigned int UQItype __attribute__ ((mode(QI)));
209typedef int SItype __attribute__ ((mode(SI)));
210typedef unsigned int USItype __attribute__ ((mode(SI)));
211typedef int DItype __attribute__ ((mode(DI)));
212typedef unsigned int UDItype __attribute__ ((mode(DI)));
213#else
214typedef unsigned char UQItype;
215typedef long SItype;
216typedef unsigned long USItype;
217#endif
218
219#ifdef __GNUC__
220#include "mpi-inline.h"
221#endif
222
223#endif /*G10_MPI_INTERNAL_H */