summaryrefslogtreecommitdiff
path: root/arch/i386/crypto/aes-i586-asm.S
blob: 911b15377f2efeded7a46a13c692770b232a79af (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
// -------------------------------------------------------------------------
// Copyright (c) 2001, Dr Brian Gladman <                 >, Worcester, UK.
// All rights reserved.
//
// LICENSE TERMS
//
// The free distribution and use of this software in both source and binary 
// form is allowed (with or without changes) provided that:
//
//   1. distributions of this source code include the above copyright 
//      notice, this list of conditions and the following disclaimer//
//
//   2. distributions in binary form include the above copyright
//      notice, this list of conditions and the following disclaimer
//      in the documentation and/or other associated materials//
//
//   3. the copyright holder's name is not used to endorse products 
//      built using this software without specific written permission.
//
//
// ALTERNATIVELY, provided that this notice is retained in full, this product
// may be distributed under the terms of the GNU General Public License (GPL),
// in which case the provisions of the GPL apply INSTEAD OF those given above.
//
// Copyright (c) 2004 Linus Torvalds <torvalds@osdl.org>
// Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>

// DISCLAIMER
//
// This software is provided 'as is' with no explicit or implied warranties
// in respect of its properties including, but not limited to, correctness 
// and fitness for purpose.
// -------------------------------------------------------------------------
// Issue Date: 29/07/2002

.file "aes-i586-asm.S"
.text

// aes_rval aes_enc_blk(const unsigned char in_blk[], unsigned char out_blk[], const aes_ctx cx[1])//
// aes_rval aes_dec_blk(const unsigned char in_blk[], unsigned char out_blk[], const aes_ctx cx[1])//
	
#define tlen 1024   // length of each of 4 'xor' arrays (256 32-bit words)

// offsets to parameters with one register pushed onto stack

#define in_blk    8  // input byte array address parameter
#define out_blk  12  // output byte array address parameter
#define ctx      16  // AES context structure

// offsets in context structure

#define ekey     0   // encryption key schedule base address
#define nrnd   256   // number of rounds
#define dkey   260   // decryption key schedule base address

// register mapping for encrypt and decrypt subroutines

#define r0  eax
#define r1  ebx
#define r2  ecx
#define r3  edx
#define r4  esi
#define r5  edi

#define eaxl  al
#define eaxh  ah
#define ebxl  bl
#define ebxh  bh
#define ecxl  cl
#define ecxh  ch
#define edxl  dl
#define edxh  dh

#define _h(reg) reg##h
#define h(reg) _h(reg)

#define _l(reg) reg##l
#define l(reg) _l(reg)

// This macro takes a 32-bit word representing a column and uses
// each of its four bytes to index into four tables of 256 32-bit
// words to obtain values that are then xored into the appropriate
// output registers r0, r1, r4 or r5.  

// Parameters:
// table table base address
//   %1  out_state[0]
//   %2  out_state[1]
//   %3  out_state[2]
//   %4  out_state[3]
//   idx input register for the round (destroyed)
//   tmp scratch register for the round
// sched key schedule

#define do_col(table, a1,a2,a3,a4, idx, tmp)	\
	movzx   %l(idx),%tmp;			\
	xor     table(,%tmp,4),%a1;		\
	movzx   %h(idx),%tmp;			\
	shr     $16,%idx;			\
	xor     table+tlen(,%tmp,4),%a2;	\
	movzx   %l(idx),%tmp;			\
	movzx   %h(idx),%idx;			\
	xor     table+2*tlen(,%tmp,4),%a3;	\
	xor     table+3*tlen(,%idx,4),%a4;

// initialise output registers from the key schedule
// NB1: original value of a3 is in idx on exit
// NB2: original values of a1,a2,a4 aren't used
#define do_fcol(table, a1,a2,a3,a4, idx, tmp, sched) \
	mov     0 sched,%a1;			\
	movzx   %l(idx),%tmp;			\
	mov     12 sched,%a2;			\
	xor     table(,%tmp,4),%a1;		\
	mov     4 sched,%a4;			\
	movzx   %h(idx),%tmp;			\
	shr     $16,%idx;			\
	xor     table+tlen(,%tmp,4),%a2;	\
	movzx   %l(idx),%tmp;			\
	movzx   %h(idx),%idx;			\
	xor     table+3*tlen(,%idx,4),%a4;	\
	mov     %a3,%idx;			\
	mov     8 sched,%a3;			\
	xor     table+2*tlen(,%tmp,4),%a3;

// initialise output registers from the key schedule
// NB1: original value of a3 is in idx on exit
// NB2: original values of a1,a2,a4 aren't used
#define do_icol(table, a1,a2,a3,a4, idx, tmp, sched) \
	mov     0 sched,%a1;			\
	movzx   %l(idx),%tmp;			\
	mov     4 sched,%a2;			\
	xor     table(,%tmp,4),%a1;		\
	mov     12 sched,%a4;			\
	movzx   %h(idx),%tmp;			\
	shr     $16,%idx;			\
	xor     table+tlen(,%tmp,4),%a2;	\
	movzx   %l(idx),%tmp;			\
	movzx   %h(idx),%idx;			\
	xor     table+3*tlen(,%idx,4),%a4;	\
	mov     %a3,%idx;			\
	mov     8 sched,%a3;			\
	xor     table+2*tlen(,%tmp,4),%a3;


// original Gladman had conditional saves to MMX regs.
#define save(a1, a2)		\
	mov     %a2,4*a1(%esp)

#define restore(a1, a2)		\
	mov     4*a2(%esp),%a1

// These macros perform a forward encryption cycle. They are entered with
// the first previous round column values in r0,r1,r4,r5 and
// exit with the final values in the same registers, using stack
// for temporary storage.

// round column values
// on entry: r0,r1,r4,r5
// on exit:  r2,r1,r4,r5
#define fwd_rnd1(arg, table)						\
	save   (0,r1);							\
	save   (1,r5);							\
									\
	/* compute new column values */					\
	do_fcol(table, r2,r5,r4,r1, r0,r3, arg);	/* idx=r0 */	\
	do_col (table, r4,r1,r2,r5, r0,r3);		/* idx=r4 */	\
	restore(r0,0);							\
	do_col (table, r1,r2,r5,r4, r0,r3);		/* idx=r1 */	\
	restore(r0,1);							\
	do_col (table, r5,r4,r1,r2, r0,r3);		/* idx=r5 */

// round column values
// on entry: r2,r1,r4,r5
// on exit:  r0,r1,r4,r5
#define fwd_rnd2(arg, table)						\
	save   (0,r1);							\
	save   (1,r5);							\
									\
	/* compute new column values */					\
	do_fcol(table, r0,r5,r4,r1, r2,r3, arg);	/* idx=r2 */	\
	do_col (table, r4,r1,r0,r5, r2,r3);		/* idx=r4 */	\
	restore(r2,0);							\
	do_col (table, r1,r0,r5,r4, r2,r3);		/* idx=r1 */	\
	restore(r2,1);							\
	do_col (table, r5,r4,r1,r0, r2,r3);		/* idx=r5 */

// These macros performs an inverse encryption cycle. They are entered with
// the first previous round column values in r0,r1,r4,r5 and
// exit with the final values in the same registers, using stack
// for temporary storage

// round column values
// on entry: r0,r1,r4,r5
// on exit:  r2,r1,r4,r5
#define inv_rnd1(arg, table)						\
	save    (0,r1);							\
	save    (1,r5);							\
									\
	/* compute new column values */					\
	do_icol(table, r2,r1,r4,r5, r0,r3, arg);	/* idx=r0 */	\
	do_col (table, r4,r5,r2,r1, r0,r3);		/* idx=r4 */	\
	restore(r0,0);							\
	do_col (table, r1,r4,r5,r2, r0,r3);		/* idx=r1 */	\
	restore(r0,1);							\
	do_col (table, r5,r2,r1,r4, r0,r3);		/* idx=r5 */

// round column values
// on entry: r2,r1,r4,r5
// on exit:  r0,r1,r4,r5
#define inv_rnd2(arg, table)						\
	save    (0,r1);							\
	save    (1,r5);							\
									\
	/* compute new column values */					\
	do_icol(table, r0,r1,r4,r5, r2,r3, arg);	/* idx=r2 */	\
	do_col (table, r4,r5,r0,r1, r2,r3);		/* idx=r4 */	\
	restore(r2,0);							\
	do_col (table, r1,r4,r5,r0, r2,r3);		/* idx=r1 */	\
	restore(r2,1);							\
	do_col (table, r5,r0,r1,r4, r2,r3);		/* idx=r5 */

// AES (Rijndael) Encryption Subroutine

.global  aes_enc_blk

.extern  ft_tab
.extern  fl_tab

.align 4

aes_enc_blk:
	push    %ebp
	mov     ctx(%esp),%ebp      // pointer to context

// CAUTION: the order and the values used in these assigns 
// rely on the register mappings

1:	push    %ebx
	mov     in_blk+4(%esp),%r2
	push    %esi
	mov     nrnd(%ebp),%r3   // number of rounds
	push    %edi
#if ekey != 0
	lea     ekey(%ebp),%ebp  // key pointer
#endif

// input four columns and xor in first round key

	mov     (%r2),%r0
	mov     4(%r2),%r1
	mov     8(%r2),%r4
	mov     12(%r2),%r5
	xor     (%ebp),%r0
	xor     4(%ebp),%r1
	xor     8(%ebp),%r4
	xor     12(%ebp),%r5

	sub     $8,%esp		// space for register saves on stack
	add     $16,%ebp	// increment to next round key
	cmp     $12,%r3
	jb      4f		// 10 rounds for 128-bit key
	lea     32(%ebp),%ebp
	je      3f		// 12 rounds for 192-bit key
	lea     32(%ebp),%ebp

2:	fwd_rnd1( -64(%ebp) ,ft_tab)	// 14 rounds for 256-bit key
	fwd_rnd2( -48(%ebp) ,ft_tab)
3:	fwd_rnd1( -32(%ebp) ,ft_tab)	// 12 rounds for 192-bit key
	fwd_rnd2( -16(%ebp) ,ft_tab)
4:	fwd_rnd1(    (%ebp) ,ft_tab)	// 10 rounds for 128-bit key
	fwd_rnd2( +16(%ebp) ,ft_tab)
	fwd_rnd1( +32(%ebp) ,ft_tab)
	fwd_rnd2( +48(%ebp) ,ft_tab)
	fwd_rnd1( +64(%ebp) ,ft_tab)
	fwd_rnd2( +80(%ebp) ,ft_tab)
	fwd_rnd1( +96(%ebp) ,ft_tab)
	fwd_rnd2(+112(%ebp) ,ft_tab)
	fwd_rnd1(+128(%ebp) ,ft_tab)
	fwd_rnd2(+144(%ebp) ,fl_tab)	// last round uses a different table

// move final values to the output array.  CAUTION: the 
// order of these assigns rely on the register mappings

	add     $8,%esp
	mov     out_blk+12(%esp),%ebp
	mov     %r5,12(%ebp)
	pop     %edi
	mov     %r4,8(%ebp)
	pop     %esi
	mov     %r1,4(%ebp)
	pop     %ebx
	mov     %r0,(%ebp)
	pop     %ebp
	mov     $1,%eax
	ret

// AES (Rijndael) Decryption Subroutine

.global  aes_dec_blk

.extern  it_tab
.extern  il_tab

.align 4

aes_dec_blk:
	push    %ebp
	mov     ctx(%esp),%ebp       // pointer to context

// CAUTION: the order and the values used in these assigns 
// rely on the register mappings

1:	push    %ebx
	mov     in_blk+4(%esp),%r2
	push    %esi
	mov     nrnd(%ebp),%r3   // number of rounds
	push    %edi
#if dkey != 0
	lea     dkey(%ebp),%ebp  // key pointer
#endif
	mov     %r3,%r0
	shl     $4,%r0
	add     %r0,%ebp
	
// input four columns and xor in first round key

	mov     (%r2),%r0
	mov     4(%r2),%r1
	mov     8(%r2),%r4
	mov     12(%r2),%r5
	xor     (%ebp),%r0
	xor     4(%ebp),%r1
	xor     8(%ebp),%r4
	xor     12(%ebp),%r5

	sub     $8,%esp		// space for register saves on stack
	sub     $16,%ebp	// increment to next round key
	cmp     $12,%r3
	jb      4f		// 10 rounds for 128-bit key
	lea     -32(%ebp),%ebp
	je      3f		// 12 rounds for 192-bit key
	lea     -32(%ebp),%ebp

2:	inv_rnd1( +64(%ebp), it_tab)	// 14 rounds for 256-bit key
	inv_rnd2( +48(%ebp), it_tab)
3:	inv_rnd1( +32(%ebp), it_tab)	// 12 rounds for 192-bit key
	inv_rnd2( +16(%ebp), it_tab)
4:	inv_rnd1(    (%ebp), it_tab)	// 10 rounds for 128-bit key
	inv_rnd2( -16(%ebp), it_tab)
	inv_rnd1( -32(%ebp), it_tab)
	inv_rnd2( -48(%ebp), it_tab)
	inv_rnd1( -64(%ebp), it_tab)
	inv_rnd2( -80(%ebp), it_tab)
	inv_rnd1( -96(%ebp), it_tab)
	inv_rnd2(-112(%ebp), it_tab)
	inv_rnd1(-128(%ebp), it_tab)
	inv_rnd2(-144(%ebp), il_tab)	// last round uses a different table

// move final values to the output array.  CAUTION: the 
// order of these assigns rely on the register mappings

	add     $8,%esp
	mov     out_blk+12(%esp),%ebp
	mov     %r5,12(%ebp)
	pop     %edi
	mov     %r4,8(%ebp)
	pop     %esi
	mov     %r1,4(%ebp)
	pop     %ebx
	mov     %r0,(%ebp)
	pop     %ebp
	mov     $1,%eax
	ret