1/* SPDX-License-Identifier: Apache-2.0 OR BSD-2-Clause */
2//
3// AES-NI optimized AES-GCM for x86_64
4//
5// Copyright 2024 Google LLC
6//
7// Author: Eric Biggers <ebiggers@google.com>
8//
9//------------------------------------------------------------------------------
10//
11// This file is dual-licensed, meaning that you can use it under your choice of
12// either of the following two licenses:
13//
14// Licensed under the Apache License 2.0 (the "License"). You may obtain a copy
15// of the License at
16//
17// http://www.apache.org/licenses/LICENSE-2.0
18//
19// Unless required by applicable law or agreed to in writing, software
20// distributed under the License is distributed on an "AS IS" BASIS,
21// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
22// See the License for the specific language governing permissions and
23// limitations under the License.
24//
25// or
26//
27// Redistribution and use in source and binary forms, with or without
28// modification, are permitted provided that the following conditions are met:
29//
30// 1. Redistributions of source code must retain the above copyright notice,
31// this list of conditions and the following disclaimer.
32//
33// 2. Redistributions in binary form must reproduce the above copyright
34// notice, this list of conditions and the following disclaimer in the
35// documentation and/or other materials provided with the distribution.
36//
37// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
38// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
39// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
40// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
41// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
42// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
43// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
44// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
45// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
46// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
47// POSSIBILITY OF SUCH DAMAGE.
48//
49//------------------------------------------------------------------------------
50//
51// This file implements AES-GCM (Galois/Counter Mode) for x86_64 CPUs that
52// support the original set of AES instructions, i.e. AES-NI. Two
53// implementations are provided, one that uses AVX and one that doesn't. They
54// are very similar, being generated by the same macros. The only difference is
55// that the AVX implementation takes advantage of VEX-coded instructions in some
56// places to avoid some 'movdqu' and 'movdqa' instructions. The AVX
57// implementation does *not* use 256-bit vectors, as AES is not supported on
58// 256-bit vectors until the VAES feature (which this file doesn't target).
59//
60// The specific CPU feature prerequisites are AES-NI and PCLMULQDQ, plus SSE4.1
61// for the *_aesni functions or AVX for the *_aesni_avx ones. (But it seems
62// there are no CPUs that support AES-NI without also PCLMULQDQ and SSE4.1.)
63//
64// The design generally follows that of aes-gcm-vaes-avx512.S, and that file is
65// more thoroughly commented. This file has the following notable changes:
66//
67// - The vector length is fixed at 128-bit, i.e. xmm registers. This means
68// there is only one AES block (and GHASH block) per register.
69//
70// - Without AVX512, only 16 SIMD registers are available instead of 32. We
71// work around this by being much more careful about using registers,
72// relying heavily on loads to load values as they are needed.
73//
74// - Masking is not available either. We work around this by implementing
75// partial block loads and stores using overlapping scalar loads and stores
76// combined with shifts and SSE4.1 insertion and extraction instructions.
77//
78// - The main loop is organized differently due to the different design
79// constraints. First, with just one AES block per SIMD register, on some
80// CPUs 4 registers don't saturate the 'aesenc' throughput. We therefore
81// do an 8-register wide loop. Considering that and the fact that we have
82// just 16 SIMD registers to work with, it's not feasible to cache AES
83// round keys and GHASH key powers in registers across loop iterations.
84// That's not ideal, but also not actually that bad, since loads can run in
85// parallel with other instructions. Significantly, this also makes it
86// possible to roll up the inner loops, relying on hardware loop unrolling
87// instead of software loop unrolling, greatly reducing code size.
88//
89// - We implement the GHASH multiplications in the main loop using Karatsuba
90// multiplication instead of schoolbook multiplication. This saves one
91// pclmulqdq instruction per block, at the cost of one 64-bit load, one
92// pshufd, and 0.25 pxors per block. (This is without the three-argument
93// XOR support that would be provided by AVX512, which would be more
94// beneficial to schoolbook than Karatsuba.)
95//
96// As a rough approximation, we can assume that Karatsuba multiplication is
97// faster than schoolbook multiplication in this context if one pshufd and
98// 0.25 pxors are cheaper than a pclmulqdq. (We assume that the 64-bit
99// load is "free" due to running in parallel with arithmetic instructions.)
100// This is true on AMD CPUs, including all that support pclmulqdq up to at
101// least Zen 3. It's also true on older Intel CPUs: Westmere through
102// Haswell on the Core side, and Silvermont through Goldmont Plus on the
103// low-power side. On some of these CPUs, pclmulqdq is quite slow, and the
104// benefit of Karatsuba should be substantial. On newer Intel CPUs,
105// schoolbook multiplication should be faster, but only marginally.
106//
107// Not all these CPUs were available to be tested. However, benchmarks on
108// available CPUs suggest that this approximation is plausible. Switching
109// to Karatsuba showed negligible change (< 1%) on Intel Broadwell,
110// Skylake, and Cascade Lake, but it improved AMD Zen 1-3 by 6-7%.
111// Considering that and the fact that Karatsuba should be even more
112// beneficial on older Intel CPUs, it seems like the right choice here.
113//
114// An additional 0.25 pclmulqdq per block (2 per 8 blocks) could be
115// saved by using a multiplication-less reduction method. We don't do that
116// because it would require a large number of shift and xor instructions,
117// making it less worthwhile and likely harmful on newer CPUs.
118//
119// It does make sense to sometimes use a different reduction optimization
120// that saves a pclmulqdq, though: precompute the hash key times x^64, and
121// multiply the low half of the data block by the hash key with the extra
122// factor of x^64. This eliminates one step of the reduction. However,
123// this is incompatible with Karatsuba multiplication. Therefore, for
124// multi-block processing we use Karatsuba multiplication with a regular
125// reduction. For single-block processing, we use the x^64 optimization.
126
127#include <linux/linkage.h>
128
129.section .rodata
130.p2align 4
131.Lbswap_mask:
132 .octa 0x000102030405060708090a0b0c0d0e0f
133.Lgfpoly:
134 .quad 0xc200000000000000
135.Lone:
136 .quad 1
137.Lgfpoly_and_internal_carrybit:
138 .octa 0xc2000000000000010000000000000001
139 // Loading 16 bytes from '.Lzeropad_mask + 16 - len' produces a mask of
140 // 'len' 0xff bytes and the rest zeroes.
141.Lzeropad_mask:
142 .octa 0xffffffffffffffffffffffffffffffff
143 .octa 0
144
145// Offsets in struct aes_gcm_key_aesni
146#define OFFSETOF_AESKEYLEN 480
147#define OFFSETOF_H_POWERS 496
148#define OFFSETOF_H_POWERS_XORED 624
149#define OFFSETOF_H_TIMES_X64 688
150
151.text
152
153// Do a vpclmulqdq, or fall back to a movdqa and a pclmulqdq. The fallback
154// assumes that all operands are distinct and that any mem operand is aligned.
155.macro _vpclmulqdq imm, src1, src2, dst
156.if USE_AVX
157 vpclmulqdq \imm, \src1, \src2, \dst
158.else
159 movdqa \src2, \dst
160 pclmulqdq \imm, \src1, \dst
161.endif
162.endm
163
164// Do a vpshufb, or fall back to a movdqa and a pshufb. The fallback assumes
165// that all operands are distinct and that any mem operand is aligned.
166.macro _vpshufb src1, src2, dst
167.if USE_AVX
168 vpshufb \src1, \src2, \dst
169.else
170 movdqa \src2, \dst
171 pshufb \src1, \dst
172.endif
173.endm
174
175// Do a vpand, or fall back to a movdqu and a pand. The fallback assumes that
176// all operands are distinct.
177.macro _vpand src1, src2, dst
178.if USE_AVX
179 vpand \src1, \src2, \dst
180.else
181 movdqu \src1, \dst
182 pand \src2, \dst
183.endif
184.endm
185
186// XOR the unaligned memory operand \mem into the xmm register \reg. \tmp must
187// be a temporary xmm register.
188.macro _xor_mem_to_reg mem, reg, tmp
189.if USE_AVX
190 vpxor \mem, \reg, \reg
191.else
192 movdqu \mem, \tmp
193 pxor \tmp, \reg
194.endif
195.endm
196
197// Test the unaligned memory operand \mem against the xmm register \reg. \tmp
198// must be a temporary xmm register.
199.macro _test_mem mem, reg, tmp
200.if USE_AVX
201 vptest \mem, \reg
202.else
203 movdqu \mem, \tmp
204 ptest \tmp, \reg
205.endif
206.endm
207
208// Load 1 <= %ecx <= 15 bytes from the pointer \src into the xmm register \dst
209// and zeroize any remaining bytes. Clobbers %rax, %rcx, and \tmp{64,32}.
210.macro _load_partial_block src, dst, tmp64, tmp32
211 sub $8, %ecx // LEN - 8
212 jle .Lle8\@
213
214 // Load 9 <= LEN <= 15 bytes.
215 movq (\src), \dst // Load first 8 bytes
216 mov (\src, %rcx), %rax // Load last 8 bytes
217 neg %ecx
218 shl $3, %ecx
219 shr %cl, %rax // Discard overlapping bytes
220 pinsrq $1, %rax, \dst
221 jmp .Ldone\@
222
223.Lle8\@:
224 add $4, %ecx // LEN - 4
225 jl .Llt4\@
226
227 // Load 4 <= LEN <= 8 bytes.
228 mov (\src), %eax // Load first 4 bytes
229 mov (\src, %rcx), \tmp32 // Load last 4 bytes
230 jmp .Lcombine\@
231
232.Llt4\@:
233 // Load 1 <= LEN <= 3 bytes.
234 add $2, %ecx // LEN - 2
235 movzbl (\src), %eax // Load first byte
236 jl .Lmovq\@
237 movzwl (\src, %rcx), \tmp32 // Load last 2 bytes
238.Lcombine\@:
239 shl $3, %ecx
240 shl %cl, \tmp64
241 or \tmp64, %rax // Combine the two parts
242.Lmovq\@:
243 movq %rax, \dst
244.Ldone\@:
245.endm
246
247// Store 1 <= %ecx <= 15 bytes from the xmm register \src to the pointer \dst.
248// Clobbers %rax, %rcx, and %rsi.
249.macro _store_partial_block src, dst
250 sub $8, %ecx // LEN - 8
251 jl .Llt8\@
252
253 // Store 8 <= LEN <= 15 bytes.
254 pextrq $1, \src, %rax
255 mov %ecx, %esi
256 shl $3, %ecx
257 ror %cl, %rax
258 mov %rax, (\dst, %rsi) // Store last LEN - 8 bytes
259 movq \src, (\dst) // Store first 8 bytes
260 jmp .Ldone\@
261
262.Llt8\@:
263 add $4, %ecx // LEN - 4
264 jl .Llt4\@
265
266 // Store 4 <= LEN <= 7 bytes.
267 pextrd $1, \src, %eax
268 mov %ecx, %esi
269 shl $3, %ecx
270 ror %cl, %eax
271 mov %eax, (\dst, %rsi) // Store last LEN - 4 bytes
272 movd \src, (\dst) // Store first 4 bytes
273 jmp .Ldone\@
274
275.Llt4\@:
276 // Store 1 <= LEN <= 3 bytes.
277 pextrb $0, \src, 0(\dst)
278 cmp $-2, %ecx // LEN - 4 == -2, i.e. LEN == 2?
279 jl .Ldone\@
280 pextrb $1, \src, 1(\dst)
281 je .Ldone\@
282 pextrb $2, \src, 2(\dst)
283.Ldone\@:
284.endm
285
286// Do one step of GHASH-multiplying \a by \b and storing the reduced product in
287// \b. To complete all steps, this must be invoked with \i=0 through \i=9.
288// \a_times_x64 must contain \a * x^64 in reduced form, \gfpoly must contain the
289// .Lgfpoly constant, and \t0-\t1 must be temporary registers.
290.macro _ghash_mul_step i, a, a_times_x64, b, gfpoly, t0, t1
291
292 // MI = (a_L * b_H) + ((a*x^64)_L * b_L)
293.if \i == 0
294 _vpclmulqdq $0x01, \a, \b, \t0
295.elseif \i == 1
296 _vpclmulqdq $0x00, \a_times_x64, \b, \t1
297.elseif \i == 2
298 pxor \t1, \t0
299
300 // HI = (a_H * b_H) + ((a*x^64)_H * b_L)
301.elseif \i == 3
302 _vpclmulqdq $0x11, \a, \b, \t1
303.elseif \i == 4
304 pclmulqdq $0x10, \a_times_x64, \b
305.elseif \i == 5
306 pxor \t1, \b
307.elseif \i == 6
308
309 // Fold MI into HI.
310 pshufd $0x4e, \t0, \t1 // Swap halves of MI
311.elseif \i == 7
312 pclmulqdq $0x00, \gfpoly, \t0 // MI_L*(x^63 + x^62 + x^57)
313.elseif \i == 8
314 pxor \t1, \b
315.elseif \i == 9
316 pxor \t0, \b
317.endif
318.endm
319
320// GHASH-multiply \a by \b and store the reduced product in \b.
321// See _ghash_mul_step for details.
322.macro _ghash_mul a, a_times_x64, b, gfpoly, t0, t1
323.irp i, 0,1,2,3,4,5,6,7,8,9
324 _ghash_mul_step \i, \a, \a_times_x64, \b, \gfpoly, \t0, \t1
325.endr
326.endm
327
328// GHASH-multiply \a by \b and add the unreduced product to \lo, \mi, and \hi.
329// This does Karatsuba multiplication and must be paired with _ghash_reduce. On
330// the first call, \lo, \mi, and \hi must be zero. \a_xored must contain the
331// two halves of \a XOR'd together, i.e. a_L + a_H. \b is clobbered.
332.macro _ghash_mul_noreduce a, a_xored, b, lo, mi, hi, t0
333
334 // LO += a_L * b_L
335 _vpclmulqdq $0x00, \a, \b, \t0
336 pxor \t0, \lo
337
338 // b_L + b_H
339 pshufd $0x4e, \b, \t0
340 pxor \b, \t0
341
342 // HI += a_H * b_H
343 pclmulqdq $0x11, \a, \b
344 pxor \b, \hi
345
346 // MI += (a_L + a_H) * (b_L + b_H)
347 pclmulqdq $0x00, \a_xored, \t0
348 pxor \t0, \mi
349.endm
350
351// Reduce the product from \lo, \mi, and \hi, and store the result in \dst.
352// This assumes that _ghash_mul_noreduce was used.
353.macro _ghash_reduce lo, mi, hi, dst, t0
354
355 movq .Lgfpoly(%rip), \t0
356
357 // MI += LO + HI (needed because we used Karatsuba multiplication)
358 pxor \lo, \mi
359 pxor \hi, \mi
360
361 // Fold LO into MI.
362 pshufd $0x4e, \lo, \dst
363 pclmulqdq $0x00, \t0, \lo
364 pxor \dst, \mi
365 pxor \lo, \mi
366
367 // Fold MI into HI.
368 pshufd $0x4e, \mi, \dst
369 pclmulqdq $0x00, \t0, \mi
370 pxor \hi, \dst
371 pxor \mi, \dst
372.endm
373
374// Do the first step of the GHASH update of a set of 8 ciphertext blocks.
375//
376// The whole GHASH update does:
377//
378// GHASH_ACC = (blk0+GHASH_ACC)*H^8 + blk1*H^7 + blk2*H^6 + blk3*H^5 +
379// blk4*H^4 + blk5*H^3 + blk6*H^2 + blk7*H^1
380//
381// This macro just does the first step: it does the unreduced multiplication
382// (blk0+GHASH_ACC)*H^8 and starts gathering the unreduced product in the xmm
383// registers LO, MI, and GHASH_ACC a.k.a. HI. It also zero-initializes the
384// inner block counter in %rax, which is a value that counts up by 8 for each
385// block in the set of 8 and is used later to index by 8*blknum and 16*blknum.
386//
387// To reduce the number of pclmulqdq instructions required, both this macro and
388// _ghash_update_continue_8x use Karatsuba multiplication instead of schoolbook
389// multiplication. See the file comment for more details about this choice.
390//
391// Both macros expect the ciphertext blocks blk[0-7] to be available at DST if
392// encrypting, or SRC if decrypting. They also expect the precomputed hash key
393// powers H^i and their XOR'd-together halves to be available in the struct
394// pointed to by KEY. Both macros clobber TMP[0-2].
395.macro _ghash_update_begin_8x enc
396
397 // Initialize the inner block counter.
398 xor %eax, %eax
399
400 // Load the highest hash key power, H^8.
401 movdqa OFFSETOF_H_POWERS(KEY), TMP0
402
403 // Load the first ciphertext block and byte-reflect it.
404.if \enc
405 movdqu (DST), TMP1
406.else
407 movdqu (SRC), TMP1
408.endif
409 pshufb BSWAP_MASK, TMP1
410
411 // Add the GHASH accumulator to the ciphertext block to get the block
412 // 'b' that needs to be multiplied with the hash key power 'a'.
413 pxor TMP1, GHASH_ACC
414
415 // b_L + b_H
416 pshufd $0x4e, GHASH_ACC, MI
417 pxor GHASH_ACC, MI
418
419 // LO = a_L * b_L
420 _vpclmulqdq $0x00, TMP0, GHASH_ACC, LO
421
422 // HI = a_H * b_H
423 pclmulqdq $0x11, TMP0, GHASH_ACC
424
425 // MI = (a_L + a_H) * (b_L + b_H)
426 pclmulqdq $0x00, OFFSETOF_H_POWERS_XORED(KEY), MI
427.endm
428
429// Continue the GHASH update of 8 ciphertext blocks as described above by doing
430// an unreduced multiplication of the next ciphertext block by the next lowest
431// key power and accumulating the result into LO, MI, and GHASH_ACC a.k.a. HI.
432.macro _ghash_update_continue_8x enc
433 add $8, %eax
434
435 // Load the next lowest key power.
436 movdqa OFFSETOF_H_POWERS(KEY,%rax,2), TMP0
437
438 // Load the next ciphertext block and byte-reflect it.
439.if \enc
440 movdqu (DST,%rax,2), TMP1
441.else
442 movdqu (SRC,%rax,2), TMP1
443.endif
444 pshufb BSWAP_MASK, TMP1
445
446 // LO += a_L * b_L
447 _vpclmulqdq $0x00, TMP0, TMP1, TMP2
448 pxor TMP2, LO
449
450 // b_L + b_H
451 pshufd $0x4e, TMP1, TMP2
452 pxor TMP1, TMP2
453
454 // HI += a_H * b_H
455 pclmulqdq $0x11, TMP0, TMP1
456 pxor TMP1, GHASH_ACC
457
458 // MI += (a_L + a_H) * (b_L + b_H)
459 movq OFFSETOF_H_POWERS_XORED(KEY,%rax), TMP1
460 pclmulqdq $0x00, TMP1, TMP2
461 pxor TMP2, MI
462.endm
463
464// Reduce LO, MI, and GHASH_ACC a.k.a. HI into GHASH_ACC. This is similar to
465// _ghash_reduce, but it's hardcoded to use the registers of the main loop and
466// it uses the same register for HI and the destination. It's also divided into
467// two steps. TMP1 must be preserved across steps.
468//
469// One pshufd could be saved by shuffling MI and XOR'ing LO into it, instead of
470// shuffling LO, XOR'ing LO into MI, and shuffling MI. However, this would
471// increase the critical path length, and it seems to slightly hurt performance.
472.macro _ghash_update_end_8x_step i
473.if \i == 0
474 movq .Lgfpoly(%rip), TMP1
475 pxor LO, MI
476 pxor GHASH_ACC, MI
477 pshufd $0x4e, LO, TMP2
478 pclmulqdq $0x00, TMP1, LO
479 pxor TMP2, MI
480 pxor LO, MI
481.elseif \i == 1
482 pshufd $0x4e, MI, TMP2
483 pclmulqdq $0x00, TMP1, MI
484 pxor TMP2, GHASH_ACC
485 pxor MI, GHASH_ACC
486.endif
487.endm
488
489// void aes_gcm_precompute_##suffix(struct aes_gcm_key_aesni *key);
490//
491// Given the expanded AES key, derive the GHASH subkey and initialize the GHASH
492// related fields in the key struct.
493.macro _aes_gcm_precompute
494
495 // Function arguments
496 .set KEY, %rdi
497
498 // Additional local variables.
499 // %xmm0-%xmm1 and %rax are used as temporaries.
500 .set RNDKEYLAST_PTR, %rsi
501 .set H_CUR, %xmm2
502 .set H_POW1, %xmm3 // H^1
503 .set H_POW1_X64, %xmm4 // H^1 * x^64
504 .set GFPOLY, %xmm5
505
506 // Encrypt an all-zeroes block to get the raw hash subkey.
507 movl OFFSETOF_AESKEYLEN(KEY), %eax
508 lea 6*16(KEY,%rax,4), RNDKEYLAST_PTR
509 movdqa (KEY), H_POW1 // Zero-th round key XOR all-zeroes block
510 lea 16(KEY), %rax
5111:
512 aesenc (%rax), H_POW1
513 add $16, %rax
514 cmp %rax, RNDKEYLAST_PTR
515 jne 1b
516 aesenclast (RNDKEYLAST_PTR), H_POW1
517
518 // Preprocess the raw hash subkey as needed to operate on GHASH's
519 // bit-reflected values directly: reflect its bytes, then multiply it by
520 // x^-1 (using the backwards interpretation of polynomial coefficients
521 // from the GCM spec) or equivalently x^1 (using the alternative,
522 // natural interpretation of polynomial coefficients).
523 pshufb .Lbswap_mask(%rip), H_POW1
524 movdqa H_POW1, %xmm0
525 pshufd $0xd3, %xmm0, %xmm0
526 psrad $31, %xmm0
527 paddq H_POW1, H_POW1
528 pand .Lgfpoly_and_internal_carrybit(%rip), %xmm0
529 pxor %xmm0, H_POW1
530
531 // Store H^1.
532 movdqa H_POW1, OFFSETOF_H_POWERS+7*16(KEY)
533
534 // Compute and store H^1 * x^64.
535 movq .Lgfpoly(%rip), GFPOLY
536 pshufd $0x4e, H_POW1, %xmm0
537 _vpclmulqdq $0x00, H_POW1, GFPOLY, H_POW1_X64
538 pxor %xmm0, H_POW1_X64
539 movdqa H_POW1_X64, OFFSETOF_H_TIMES_X64(KEY)
540
541 // Compute and store the halves of H^1 XOR'd together.
542 pxor H_POW1, %xmm0
543 movq %xmm0, OFFSETOF_H_POWERS_XORED+7*8(KEY)
544
545 // Compute and store the remaining key powers H^2 through H^8.
546 movdqa H_POW1, H_CUR
547 mov $6*8, %eax
548.Lprecompute_next\@:
549 // Compute H^i = H^{i-1} * H^1.
550 _ghash_mul H_POW1, H_POW1_X64, H_CUR, GFPOLY, %xmm0, %xmm1
551 // Store H^i.
552 movdqa H_CUR, OFFSETOF_H_POWERS(KEY,%rax,2)
553 // Compute and store the halves of H^i XOR'd together.
554 pshufd $0x4e, H_CUR, %xmm0
555 pxor H_CUR, %xmm0
556 movq %xmm0, OFFSETOF_H_POWERS_XORED(KEY,%rax)
557 sub $8, %eax
558 jge .Lprecompute_next\@
559
560 RET
561.endm
562
563// void aes_gcm_aad_update_aesni(const struct aes_gcm_key_aesni *key,
564// u8 ghash_acc[16], const u8 *aad, int aadlen);
565//
566// This function processes the AAD (Additional Authenticated Data) in GCM.
567// Using the key |key|, it updates the GHASH accumulator |ghash_acc| with the
568// data given by |aad| and |aadlen|. On the first call, |ghash_acc| must be all
569// zeroes. |aadlen| must be a multiple of 16, except on the last call where it
570// can be any length. The caller must do any buffering needed to ensure this.
571.macro _aes_gcm_aad_update
572
573 // Function arguments
574 .set KEY, %rdi
575 .set GHASH_ACC_PTR, %rsi
576 .set AAD, %rdx
577 .set AADLEN, %ecx
578 // Note: _load_partial_block relies on AADLEN being in %ecx.
579
580 // Additional local variables.
581 // %rax, %r10, and %xmm0-%xmm1 are used as temporary registers.
582 .set BSWAP_MASK, %xmm2
583 .set GHASH_ACC, %xmm3
584 .set H_POW1, %xmm4 // H^1
585 .set H_POW1_X64, %xmm5 // H^1 * x^64
586 .set GFPOLY, %xmm6
587
588 movdqa .Lbswap_mask(%rip), BSWAP_MASK
589 movdqu (GHASH_ACC_PTR), GHASH_ACC
590 movdqa OFFSETOF_H_POWERS+7*16(KEY), H_POW1
591 movdqa OFFSETOF_H_TIMES_X64(KEY), H_POW1_X64
592 movq .Lgfpoly(%rip), GFPOLY
593
594 // Process the AAD one full block at a time.
595 sub $16, AADLEN
596 jl .Laad_loop_1x_done\@
597.Laad_loop_1x\@:
598 movdqu (AAD), %xmm0
599 pshufb BSWAP_MASK, %xmm0
600 pxor %xmm0, GHASH_ACC
601 _ghash_mul H_POW1, H_POW1_X64, GHASH_ACC, GFPOLY, %xmm0, %xmm1
602 add $16, AAD
603 sub $16, AADLEN
604 jge .Laad_loop_1x\@
605.Laad_loop_1x_done\@:
606 // Check whether there is a partial block at the end.
607 add $16, AADLEN
608 jz .Laad_done\@
609
610 // Process a partial block of length 1 <= AADLEN <= 15.
611 // _load_partial_block assumes that %ecx contains AADLEN.
612 _load_partial_block AAD, %xmm0, %r10, %r10d
613 pshufb BSWAP_MASK, %xmm0
614 pxor %xmm0, GHASH_ACC
615 _ghash_mul H_POW1, H_POW1_X64, GHASH_ACC, GFPOLY, %xmm0, %xmm1
616
617.Laad_done\@:
618 movdqu GHASH_ACC, (GHASH_ACC_PTR)
619 RET
620.endm
621
622// Increment LE_CTR eight times to generate eight little-endian counter blocks,
623// swap each to big-endian, and store them in AESDATA[0-7]. Also XOR them with
624// the zero-th AES round key. Clobbers TMP0 and TMP1.
625.macro _ctr_begin_8x
626 movq .Lone(%rip), TMP0
627 movdqa (KEY), TMP1 // zero-th round key
628.irp i, 0,1,2,3,4,5,6,7
629 _vpshufb BSWAP_MASK, LE_CTR, AESDATA\i
630 pxor TMP1, AESDATA\i
631 paddd TMP0, LE_CTR
632.endr
633.endm
634
635// Do a non-last round of AES on AESDATA[0-7] using \round_key.
636.macro _aesenc_8x round_key
637.irp i, 0,1,2,3,4,5,6,7
638 aesenc \round_key, AESDATA\i
639.endr
640.endm
641
642// Do the last round of AES on AESDATA[0-7] using \round_key.
643.macro _aesenclast_8x round_key
644.irp i, 0,1,2,3,4,5,6,7
645 aesenclast \round_key, AESDATA\i
646.endr
647.endm
648
649// XOR eight blocks from SRC with the keystream blocks in AESDATA[0-7], and
650// store the result to DST. Clobbers TMP0.
651.macro _xor_data_8x
652.irp i, 0,1,2,3,4,5,6,7
653 _xor_mem_to_reg \i*16(SRC), AESDATA\i, tmp=TMP0
654.endr
655.irp i, 0,1,2,3,4,5,6,7
656 movdqu AESDATA\i, \i*16(DST)
657.endr
658.endm
659
660// void aes_gcm_{enc,dec}_update_##suffix(const struct aes_gcm_key_aesni *key,
661// const u32 le_ctr[4], u8 ghash_acc[16],
662// const u8 *src, u8 *dst, int datalen);
663//
664// This macro generates a GCM encryption or decryption update function with the
665// above prototype (with \enc selecting which one).
666//
667// This function computes the next portion of the CTR keystream, XOR's it with
668// |datalen| bytes from |src|, and writes the resulting encrypted or decrypted
669// data to |dst|. It also updates the GHASH accumulator |ghash_acc| using the
670// next |datalen| ciphertext bytes.
671//
672// |datalen| must be a multiple of 16, except on the last call where it can be
673// any length. The caller must do any buffering needed to ensure this. Both
674// in-place and out-of-place en/decryption are supported.
675//
676// |le_ctr| must give the current counter in little-endian format. For a new
677// message, the low word of the counter must be 2. This function loads the
678// counter from |le_ctr| and increments the loaded counter as needed, but it
679// does *not* store the updated counter back to |le_ctr|. The caller must
680// update |le_ctr| if any more data segments follow. Internally, only the low
681// 32-bit word of the counter is incremented, following the GCM standard.
682.macro _aes_gcm_update enc
683
684 // Function arguments
685 .set KEY, %rdi
686 .set LE_CTR_PTR, %rsi // Note: overlaps with usage as temp reg
687 .set GHASH_ACC_PTR, %rdx
688 .set SRC, %rcx
689 .set DST, %r8
690 .set DATALEN, %r9d
691 .set DATALEN64, %r9 // Zero-extend DATALEN before using!
692 // Note: the code setting up for _load_partial_block assumes that SRC is
693 // in %rcx (and that DATALEN is *not* in %rcx).
694
695 // Additional local variables
696
697 // %rax and %rsi are used as temporary registers. Note: %rsi overlaps
698 // with LE_CTR_PTR, which is used only at the beginning.
699
700 .set AESKEYLEN, %r10d // AES key length in bytes
701 .set AESKEYLEN64, %r10
702 .set RNDKEYLAST_PTR, %r11 // Pointer to last AES round key
703
704 // Put the most frequently used values in %xmm0-%xmm7 to reduce code
705 // size. (%xmm0-%xmm7 take fewer bytes to encode than %xmm8-%xmm15.)
706 .set TMP0, %xmm0
707 .set TMP1, %xmm1
708 .set TMP2, %xmm2
709 .set LO, %xmm3 // Low part of unreduced product
710 .set MI, %xmm4 // Middle part of unreduced product
711 .set GHASH_ACC, %xmm5 // GHASH accumulator; in main loop also
712 // the high part of unreduced product
713 .set BSWAP_MASK, %xmm6 // Shuffle mask for reflecting bytes
714 .set LE_CTR, %xmm7 // Little-endian counter value
715 .set AESDATA0, %xmm8
716 .set AESDATA1, %xmm9
717 .set AESDATA2, %xmm10
718 .set AESDATA3, %xmm11
719 .set AESDATA4, %xmm12
720 .set AESDATA5, %xmm13
721 .set AESDATA6, %xmm14
722 .set AESDATA7, %xmm15
723
724 movdqa .Lbswap_mask(%rip), BSWAP_MASK
725 movdqu (GHASH_ACC_PTR), GHASH_ACC
726 movdqu (LE_CTR_PTR), LE_CTR
727
728 movl OFFSETOF_AESKEYLEN(KEY), AESKEYLEN
729 lea 6*16(KEY,AESKEYLEN64,4), RNDKEYLAST_PTR
730
731 // If there are at least 8*16 bytes of data, then continue into the main
732 // loop, which processes 8*16 bytes of data per iteration.
733 //
734 // The main loop interleaves AES and GHASH to improve performance on
735 // CPUs that can execute these instructions in parallel. When
736 // decrypting, the GHASH input (the ciphertext) is immediately
737 // available. When encrypting, we instead encrypt a set of 8 blocks
738 // first and then GHASH those blocks while encrypting the next set of 8,
739 // repeat that as needed, and finally GHASH the last set of 8 blocks.
740 //
741 // Code size optimization: Prefer adding or subtracting -8*16 over 8*16,
742 // as this makes the immediate fit in a signed byte, saving 3 bytes.
743 add $-8*16, DATALEN
744 jl .Lcrypt_loop_8x_done\@
745.if \enc
746 // Encrypt the first 8 plaintext blocks.
747 _ctr_begin_8x
748 lea 16(KEY), %rsi
749 .p2align 4
7501:
751 movdqa (%rsi), TMP0
752 _aesenc_8x TMP0
753 add $16, %rsi
754 cmp %rsi, RNDKEYLAST_PTR
755 jne 1b
756 movdqa (%rsi), TMP0
757 _aesenclast_8x TMP0
758 _xor_data_8x
759 // Don't increment DST until the ciphertext blocks have been hashed.
760 sub $-8*16, SRC
761 add $-8*16, DATALEN
762 jl .Lghash_last_ciphertext_8x\@
763.endif
764
765 .p2align 4
766.Lcrypt_loop_8x\@:
767
768 // Generate the next set of 8 counter blocks and start encrypting them.
769 _ctr_begin_8x
770 lea 16(KEY), %rsi
771
772 // Do a round of AES, and start the GHASH update of 8 ciphertext blocks
773 // by doing the unreduced multiplication for the first ciphertext block.
774 movdqa (%rsi), TMP0
775 add $16, %rsi
776 _aesenc_8x TMP0
777 _ghash_update_begin_8x \enc
778
779 // Do 7 more rounds of AES, and continue the GHASH update by doing the
780 // unreduced multiplication for the remaining ciphertext blocks.
781 .p2align 4
7821:
783 movdqa (%rsi), TMP0
784 add $16, %rsi
785 _aesenc_8x TMP0
786 _ghash_update_continue_8x \enc
787 cmp $7*8, %eax
788 jne 1b
789
790 // Do the remaining AES rounds.
791 .p2align 4
7921:
793 movdqa (%rsi), TMP0
794 add $16, %rsi
795 _aesenc_8x TMP0
796 cmp %rsi, RNDKEYLAST_PTR
797 jne 1b
798
799 // Do the GHASH reduction and the last round of AES.
800 movdqa (RNDKEYLAST_PTR), TMP0
801 _ghash_update_end_8x_step 0
802 _aesenclast_8x TMP0
803 _ghash_update_end_8x_step 1
804
805 // XOR the data with the AES-CTR keystream blocks.
806.if \enc
807 sub $-8*16, DST
808.endif
809 _xor_data_8x
810 sub $-8*16, SRC
811.if !\enc
812 sub $-8*16, DST
813.endif
814 add $-8*16, DATALEN
815 jge .Lcrypt_loop_8x\@
816
817.if \enc
818.Lghash_last_ciphertext_8x\@:
819 // Update GHASH with the last set of 8 ciphertext blocks.
820 _ghash_update_begin_8x \enc
821 .p2align 4
8221:
823 _ghash_update_continue_8x \enc
824 cmp $7*8, %eax
825 jne 1b
826 _ghash_update_end_8x_step 0
827 _ghash_update_end_8x_step 1
828 sub $-8*16, DST
829.endif
830
831.Lcrypt_loop_8x_done\@:
832
833 sub $-8*16, DATALEN
834 jz .Ldone\@
835
836 // Handle the remainder of length 1 <= DATALEN < 8*16 bytes. We keep
837 // things simple and keep the code size down by just going one block at
838 // a time, again taking advantage of hardware loop unrolling. Since
839 // there are enough key powers available for all remaining data, we do
840 // the GHASH multiplications unreduced, and only reduce at the very end.
841
842 .set HI, TMP2
843 .set H_POW, AESDATA0
844 .set H_POW_XORED, AESDATA1
845 .set ONE, AESDATA2
846
847 movq .Lone(%rip), ONE
848
849 // Start collecting the unreduced GHASH intermediate value LO, MI, HI.
850 pxor LO, LO
851 pxor MI, MI
852 pxor HI, HI
853
854 // Set up a block counter %rax to contain 8*(8-n), where n is the number
855 // of blocks that remain, counting any partial block. This will be used
856 // to access the key powers H^n through H^1.
857 mov DATALEN, %eax
858 neg %eax
859 and $~15, %eax
860 sar $1, %eax
861 add $64, %eax
862
863 sub $16, DATALEN
864 jl .Lcrypt_loop_1x_done\@
865
866 // Process the data one full block at a time.
867.Lcrypt_loop_1x\@:
868
869 // Encrypt the next counter block.
870 _vpshufb BSWAP_MASK, LE_CTR, TMP0
871 paddd ONE, LE_CTR
872 pxor (KEY), TMP0
873 lea -6*16(RNDKEYLAST_PTR), %rsi // Reduce code size
874 cmp $24, AESKEYLEN
875 jl 128f // AES-128?
876 je 192f // AES-192?
877 // AES-256
878 aesenc -7*16(%rsi), TMP0
879 aesenc -6*16(%rsi), TMP0
880192:
881 aesenc -5*16(%rsi), TMP0
882 aesenc -4*16(%rsi), TMP0
883128:
884.irp i, -3,-2,-1,0,1,2,3,4,5
885 aesenc \i*16(%rsi), TMP0
886.endr
887 aesenclast (RNDKEYLAST_PTR), TMP0
888
889 // Load the next key power H^i.
890 movdqa OFFSETOF_H_POWERS(KEY,%rax,2), H_POW
891 movq OFFSETOF_H_POWERS_XORED(KEY,%rax), H_POW_XORED
892
893 // XOR the keystream block that was just generated in TMP0 with the next
894 // source data block and store the resulting en/decrypted data to DST.
895.if \enc
896 _xor_mem_to_reg (SRC), TMP0, tmp=TMP1
897 movdqu TMP0, (DST)
898.else
899 movdqu (SRC), TMP1
900 pxor TMP1, TMP0
901 movdqu TMP0, (DST)
902.endif
903
904 // Update GHASH with the ciphertext block.
905.if \enc
906 pshufb BSWAP_MASK, TMP0
907 pxor TMP0, GHASH_ACC
908.else
909 pshufb BSWAP_MASK, TMP1
910 pxor TMP1, GHASH_ACC
911.endif
912 _ghash_mul_noreduce H_POW, H_POW_XORED, GHASH_ACC, LO, MI, HI, TMP0
913 pxor GHASH_ACC, GHASH_ACC
914
915 add $8, %eax
916 add $16, SRC
917 add $16, DST
918 sub $16, DATALEN
919 jge .Lcrypt_loop_1x\@
920.Lcrypt_loop_1x_done\@:
921 // Check whether there is a partial block at the end.
922 add $16, DATALEN
923 jz .Lghash_reduce\@
924
925 // Process a partial block of length 1 <= DATALEN <= 15.
926
927 // Encrypt a counter block for the last time.
928 pshufb BSWAP_MASK, LE_CTR
929 pxor (KEY), LE_CTR
930 lea 16(KEY), %rsi
9311:
932 aesenc (%rsi), LE_CTR
933 add $16, %rsi
934 cmp %rsi, RNDKEYLAST_PTR
935 jne 1b
936 aesenclast (RNDKEYLAST_PTR), LE_CTR
937
938 // Load the lowest key power, H^1.
939 movdqa OFFSETOF_H_POWERS(KEY,%rax,2), H_POW
940 movq OFFSETOF_H_POWERS_XORED(KEY,%rax), H_POW_XORED
941
942 // Load and zero-pad 1 <= DATALEN <= 15 bytes of data from SRC. SRC is
943 // in %rcx, but _load_partial_block needs DATALEN in %rcx instead.
944 // RNDKEYLAST_PTR is no longer needed, so reuse it for SRC.
945 mov SRC, RNDKEYLAST_PTR
946 mov DATALEN, %ecx
947 _load_partial_block RNDKEYLAST_PTR, TMP0, %rsi, %esi
948
949 // XOR the keystream block that was just generated in LE_CTR with the
950 // source data block and store the resulting en/decrypted data to DST.
951 pxor TMP0, LE_CTR
952 mov DATALEN, %ecx
953 _store_partial_block LE_CTR, DST
954
955 // If encrypting, zero-pad the final ciphertext block for GHASH. (If
956 // decrypting, this was already done by _load_partial_block.)
957.if \enc
958 lea .Lzeropad_mask+16(%rip), %rax
959 sub DATALEN64, %rax
960 _vpand (%rax), LE_CTR, TMP0
961.endif
962
963 // Update GHASH with the final ciphertext block.
964 pshufb BSWAP_MASK, TMP0
965 pxor TMP0, GHASH_ACC
966 _ghash_mul_noreduce H_POW, H_POW_XORED, GHASH_ACC, LO, MI, HI, TMP0
967
968.Lghash_reduce\@:
969 // Finally, do the GHASH reduction.
970 _ghash_reduce LO, MI, HI, GHASH_ACC, TMP0
971
972.Ldone\@:
973 // Store the updated GHASH accumulator back to memory.
974 movdqu GHASH_ACC, (GHASH_ACC_PTR)
975
976 RET
977.endm
978
979// void aes_gcm_enc_final_##suffix(const struct aes_gcm_key_aesni *key,
980// const u32 le_ctr[4], u8 ghash_acc[16],
981// u64 total_aadlen, u64 total_datalen);
982// bool aes_gcm_dec_final_##suffix(const struct aes_gcm_key_aesni *key,
983// const u32 le_ctr[4], const u8 ghash_acc[16],
984// u64 total_aadlen, u64 total_datalen,
985// const u8 tag[16], int taglen);
986//
987// This macro generates one of the above two functions (with \enc selecting
988// which one). Both functions finish computing the GCM authentication tag by
989// updating GHASH with the lengths block and encrypting the GHASH accumulator.
990// |total_aadlen| and |total_datalen| must be the total length of the additional
991// authenticated data and the en/decrypted data in bytes, respectively.
992//
993// The encryption function then stores the full-length (16-byte) computed
994// authentication tag to |ghash_acc|. The decryption function instead loads the
995// expected authentication tag (the one that was transmitted) from the 16-byte
996// buffer |tag|, compares the first 4 <= |taglen| <= 16 bytes of it to the
997// computed tag in constant time, and returns true if and only if they match.
998.macro _aes_gcm_final enc
999
1000 // Function arguments
1001 .set KEY, %rdi
1002 .set LE_CTR_PTR, %rsi
1003 .set GHASH_ACC_PTR, %rdx
1004 .set TOTAL_AADLEN, %rcx
1005 .set TOTAL_DATALEN, %r8
1006 .set TAG, %r9
1007 .set TAGLEN, %r10d // Originally at 8(%rsp)
1008 .set TAGLEN64, %r10
1009
1010 // Additional local variables.
1011 // %rax and %xmm0-%xmm2 are used as temporary registers.
1012 .set AESKEYLEN, %r11d
1013 .set AESKEYLEN64, %r11
1014 .set BSWAP_MASK, %xmm3
1015 .set GHASH_ACC, %xmm4
1016 .set H_POW1, %xmm5 // H^1
1017 .set H_POW1_X64, %xmm6 // H^1 * x^64
1018 .set GFPOLY, %xmm7
1019
1020 movdqa .Lbswap_mask(%rip), BSWAP_MASK
1021 movl OFFSETOF_AESKEYLEN(KEY), AESKEYLEN
1022
1023 // Set up a counter block with 1 in the low 32-bit word. This is the
1024 // counter that produces the ciphertext needed to encrypt the auth tag.
1025 movdqu (LE_CTR_PTR), %xmm0
1026 mov $1, %eax
1027 pinsrd $0, %eax, %xmm0
1028
1029 // Build the lengths block and XOR it into the GHASH accumulator.
1030 movq TOTAL_DATALEN, GHASH_ACC
1031 pinsrq $1, TOTAL_AADLEN, GHASH_ACC
1032 psllq $3, GHASH_ACC // Bytes to bits
1033 _xor_mem_to_reg (GHASH_ACC_PTR), GHASH_ACC, %xmm1
1034
1035 movdqa OFFSETOF_H_POWERS+7*16(KEY), H_POW1
1036 movdqa OFFSETOF_H_TIMES_X64(KEY), H_POW1_X64
1037 movq .Lgfpoly(%rip), GFPOLY
1038
1039 // Make %rax point to the 6th from last AES round key. (Using signed
1040 // byte offsets -7*16 through 6*16 decreases code size.)
1041 lea (KEY,AESKEYLEN64,4), %rax
1042
1043 // AES-encrypt the counter block and also multiply GHASH_ACC by H^1.
1044 // Interleave the AES and GHASH instructions to improve performance.
1045 pshufb BSWAP_MASK, %xmm0
1046 pxor (KEY), %xmm0
1047 cmp $24, AESKEYLEN
1048 jl 128f // AES-128?
1049 je 192f // AES-192?
1050 // AES-256
1051 aesenc -7*16(%rax), %xmm0
1052 aesenc -6*16(%rax), %xmm0
1053192:
1054 aesenc -5*16(%rax), %xmm0
1055 aesenc -4*16(%rax), %xmm0
1056128:
1057.irp i, 0,1,2,3,4,5,6,7,8
1058 aesenc (\i-3)*16(%rax), %xmm0
1059 _ghash_mul_step \i, H_POW1, H_POW1_X64, GHASH_ACC, GFPOLY, %xmm1, %xmm2
1060.endr
1061 aesenclast 6*16(%rax), %xmm0
1062 _ghash_mul_step 9, H_POW1, H_POW1_X64, GHASH_ACC, GFPOLY, %xmm1, %xmm2
1063
1064 // Undo the byte reflection of the GHASH accumulator.
1065 pshufb BSWAP_MASK, GHASH_ACC
1066
1067 // Encrypt the GHASH accumulator.
1068 pxor %xmm0, GHASH_ACC
1069
1070.if \enc
1071 // Return the computed auth tag.
1072 movdqu GHASH_ACC, (GHASH_ACC_PTR)
1073.else
1074 .set ZEROPAD_MASK_PTR, TOTAL_AADLEN // Reusing TOTAL_AADLEN!
1075
1076 // Verify the auth tag in constant time by XOR'ing the transmitted and
1077 // computed auth tags together and using the ptest instruction to check
1078 // whether the first TAGLEN bytes of the result are zero.
1079 _xor_mem_to_reg (TAG), GHASH_ACC, tmp=%xmm0
1080 movl 8(%rsp), TAGLEN
1081 lea .Lzeropad_mask+16(%rip), ZEROPAD_MASK_PTR
1082 sub TAGLEN64, ZEROPAD_MASK_PTR
1083 xor %eax, %eax
1084 _test_mem (ZEROPAD_MASK_PTR), GHASH_ACC, tmp=%xmm0
1085 sete %al
1086.endif
1087 RET
1088.endm
1089
1090.set USE_AVX, 0
1091SYM_FUNC_START(aes_gcm_precompute_aesni)
1092 _aes_gcm_precompute
1093SYM_FUNC_END(aes_gcm_precompute_aesni)
1094SYM_FUNC_START(aes_gcm_aad_update_aesni)
1095 _aes_gcm_aad_update
1096SYM_FUNC_END(aes_gcm_aad_update_aesni)
1097SYM_FUNC_START(aes_gcm_enc_update_aesni)
1098 _aes_gcm_update 1
1099SYM_FUNC_END(aes_gcm_enc_update_aesni)
1100SYM_FUNC_START(aes_gcm_dec_update_aesni)
1101 _aes_gcm_update 0
1102SYM_FUNC_END(aes_gcm_dec_update_aesni)
1103SYM_FUNC_START(aes_gcm_enc_final_aesni)
1104 _aes_gcm_final 1
1105SYM_FUNC_END(aes_gcm_enc_final_aesni)
1106SYM_FUNC_START(aes_gcm_dec_final_aesni)
1107 _aes_gcm_final 0
1108SYM_FUNC_END(aes_gcm_dec_final_aesni)
1109
1110.set USE_AVX, 1
1111SYM_FUNC_START(aes_gcm_precompute_aesni_avx)
1112 _aes_gcm_precompute
1113SYM_FUNC_END(aes_gcm_precompute_aesni_avx)
1114SYM_FUNC_START(aes_gcm_aad_update_aesni_avx)
1115 _aes_gcm_aad_update
1116SYM_FUNC_END(aes_gcm_aad_update_aesni_avx)
1117SYM_FUNC_START(aes_gcm_enc_update_aesni_avx)
1118 _aes_gcm_update 1
1119SYM_FUNC_END(aes_gcm_enc_update_aesni_avx)
1120SYM_FUNC_START(aes_gcm_dec_update_aesni_avx)
1121 _aes_gcm_update 0
1122SYM_FUNC_END(aes_gcm_dec_update_aesni_avx)
1123SYM_FUNC_START(aes_gcm_enc_final_aesni_avx)
1124 _aes_gcm_final 1
1125SYM_FUNC_END(aes_gcm_enc_final_aesni_avx)
1126SYM_FUNC_START(aes_gcm_dec_final_aesni_avx)
1127 _aes_gcm_final 0
1128SYM_FUNC_END(aes_gcm_dec_final_aesni_avx)
1129

source code of linux/arch/x86/crypto/aes-gcm-aesni-x86_64.S