Re: [PATCH] crypto: twofish - add x86_64/avx assembler implementation

From: Jussi Kivilinna
Date: Wed Aug 15 2012 - 13:34:25 EST


Quoting Borislav Petkov <bp@xxxxxxxxx>:

> On Wed, Aug 15, 2012 at 05:22:03PM +0300, Jussi Kivilinna wrote:
>
>> Patch replaces 'movb' instructions with 'movzbl' to break false
>> register dependencies and interleaves instructions better for
>> out-of-order scheduling.
>>
>> Also move common round code to separate function to reduce object
>> size.
>
> Ok, redid the first test
>

Thanks.

> $ modprobe twofish-avx-x86_64
> $ modprobe tcrypt mode=504 sec=1
>
> and from quickly juxtaposing the two results, I'd say the patch makes
> things slightly worse but you'd need to run your scripts on it to get
> the accurate results:
>

About ~5% slower, probably because I was tuning for sandy-bridge and introduced
more FPU<=>CPU register moves.

Here's new version of patch, with FPU<=>CPU moves from original implementation.

(Note: also changes encryption function to inline all code in to main function,
decryption still places common code to separate function to reduce object size.
This is to measure the difference.)

-Jussi

---
arch/x86/crypto/twofish-avx-x86_64-asm_64.S | 124 +++++++++++++++++----------
1 file changed, 77 insertions(+), 47 deletions(-)

diff --git a/arch/x86/crypto/twofish-avx-x86_64-asm_64.S b/arch/x86/crypto/twofish-avx-x86_64-asm_64.S
index 35f4557..d331ab8 100644
--- a/arch/x86/crypto/twofish-avx-x86_64-asm_64.S
+++ b/arch/x86/crypto/twofish-avx-x86_64-asm_64.S
@@ -47,15 +47,22 @@
#define RC2 %xmm6
#define RD2 %xmm7

-#define RX %xmm8
-#define RY %xmm9
+#define RX0 %xmm8
+#define RY0 %xmm9

-#define RK1 %xmm10
-#define RK2 %xmm11
+#define RX1 %xmm10
+#define RY1 %xmm11
+
+#define RK1 %xmm12
+#define RK2 %xmm13
+
+#define RT %xmm14

#define RID1 %rax
+#define RID1d %eax
#define RID1b %al
#define RID2 %rbx
+#define RID2d %ebx
#define RID2b %bl

#define RGI1 %rdx
@@ -73,40 +80,48 @@
#define RGS3d %r10d


-#define lookup_32bit(t0, t1, t2, t3, src, dst) \
- movb src ## bl, RID1b; \
- movb src ## bh, RID2b; \
+#define lookup_32bit(t0, t1, t2, t3, src, dst, interleave_op, il_reg) \
+ movzbl src ## bl, RID1d; \
+ movzbl src ## bh, RID2d; \
+ shrq $16, src; \
movl t0(CTX, RID1, 4), dst ## d; \
xorl t1(CTX, RID2, 4), dst ## d; \
- shrq $16, src; \
- movb src ## bl, RID1b; \
- movb src ## bh, RID2b; \
+ movzbl src ## bl, RID1d; \
+ movzbl src ## bh, RID2d; \
+ interleave_op(il_reg); \
xorl t2(CTX, RID1, 4), dst ## d; \
xorl t3(CTX, RID2, 4), dst ## d;

+#define dummy(d) /* do nothing */
+
+#define shr_next(reg) \
+ shrq $16, reg;
+
#define G(a, x, t0, t1, t2, t3) \
- vmovq a, RGI1; \
- vpsrldq $8, a, x; \
- vmovq x, RGI2; \
+ vmovq a, RGI1; \
+ vpextrq $1, a, RGI2; \
\
- lookup_32bit(t0, t1, t2, t3, RGI1, RGS1); \
- shrq $16, RGI1; \
- lookup_32bit(t0, t1, t2, t3, RGI1, RGS2); \
+ lookup_32bit(t0, t1, t2, t3, RGI1, RGS1, shr_next, RGI1); \
+ lookup_32bit(t0, t1, t2, t3, RGI1, RGS2, dummy, none); \
shlq $32, RGS2; \
orq RGS1, RGS2; \
\
- lookup_32bit(t0, t1, t2, t3, RGI2, RGS1); \
- shrq $16, RGI2; \
- lookup_32bit(t0, t1, t2, t3, RGI2, RGS3); \
- shlq $32, RGS3; \
+ lookup_32bit(t0, t1, t2, t3, RGI2, RGS3, shr_next, RGI2); \
+ lookup_32bit(t0, t1, t2, t3, RGI2, RGS1, dummy, none); \
+ shlq $32, RGS1; \
orq RGS1, RGS3; \
\
vmovq RGS2, x; \
vpinsrq $1, RGS3, x, x;

-#define encround(a, b, c, d, x, y) \
- G(a, x, s0, s1, s2, s3); \
- G(b, y, s1, s2, s3, s0); \
+#define encround_g1g2(a, b, c, d, x, y) \
+ G(a, x, s0, s1, s2, s3); \
+ G(b, y, s1, s2, s3, s0);
+
+#define encround_end(a, b, c, d, x, y) \
+ vpslld $1, d, RT; \
+ vpsrld $(32 - 1), d, d; \
+ vpor d, RT, d; \
vpaddd x, y, x; \
vpaddd y, x, y; \
vpaddd x, RK1, x; \
@@ -115,14 +130,16 @@
vpsrld $1, c, x; \
vpslld $(32 - 1), c, c; \
vpor c, x, c; \
- vpslld $1, d, x; \
- vpsrld $(32 - 1), d, d; \
- vpor d, x, d; \
vpxor d, y, d;

-#define decround(a, b, c, d, x, y) \
- G(a, x, s0, s1, s2, s3); \
- G(b, y, s1, s2, s3, s0); \
+#define decround_g1g2(a, b, c, d, x, y) \
+ G(a, x, s0, s1, s2, s3); \
+ G(b, y, s1, s2, s3, s0);
+
+#define decround_end(a, b, c, d, x, y) \
+ vpslld $1, c, RT; \
+ vpsrld $(32 - 1), c, c; \
+ vpor c, RT, c; \
vpaddd x, y, x; \
vpaddd y, x, y; \
vpaddd y, RK2, y; \
@@ -130,23 +147,37 @@
vpsrld $1, d, y; \
vpslld $(32 - 1), d, d; \
vpor d, y, d; \
- vpslld $1, c, y; \
- vpsrld $(32 - 1), c, c; \
- vpor c, y, c; \
vpaddd x, RK1, x; \
vpxor x, c, c;

#define encrypt_round(n, a, b, c, d) \
vbroadcastss (k+4*(2*(n)))(CTX), RK1; \
vbroadcastss (k+4*(2*(n)+1))(CTX), RK2; \
- encround(a ## 1, b ## 1, c ## 1, d ## 1, RX, RY); \
- encround(a ## 2, b ## 2, c ## 2, d ## 2, RX, RY);
+ encround_g1g2(a ## 1, b ## 1, c ## 1, d ## 1, RX0, RY0); \
+ encround_g1g2(a ## 2, b ## 2, c ## 2, d ## 2, RX1, RY1); \
+ encround_end(a ## 1, b ## 1, c ## 1, d ## 1, RX0, RY0); \
+ encround_end(a ## 2, b ## 2, c ## 2, d ## 2, RX1, RY1);
+
+.align 4
+decround_RARBRCRD:
+ decround_g1g2(RA1, RB1, RC1, RD1, RX0, RY0);
+ decround_g1g2(RA2, RB2, RC2, RD2, RX1, RY1);
+ decround_end(RA1, RB1, RC1, RD1, RX0, RY0);
+ decround_end(RA2, RB2, RC2, RD2, RX1, RY1);
+ ret;
+
+.align 4
+decround_RCRDRARB:
+ decround_g1g2(RC1, RD1, RA1, RB1, RX0, RY0);
+ decround_g1g2(RC2, RD2, RA2, RB2, RX1, RY1);
+ decround_end(RC1, RD1, RA1, RB1, RX0, RY0);
+ decround_end(RC2, RD2, RA2, RB2, RX1, RY1);
+ ret;

#define decrypt_round(n, a, b, c, d) \
vbroadcastss (k+4*(2*(n)))(CTX), RK1; \
vbroadcastss (k+4*(2*(n)+1))(CTX), RK2; \
- decround(a ## 1, b ## 1, c ## 1, d ## 1, RX, RY); \
- decround(a ## 2, b ## 2, c ## 2, d ## 2, RX, RY);
+ call decround_ ## a ## b ## c ## d;

#define encrypt_cycle(n) \
encrypt_round((2*n), RA, RB, RC, RD); \
@@ -156,7 +187,6 @@
decrypt_round(((2*n) + 1), RC, RD, RA, RB); \
decrypt_round((2*n), RA, RB, RC, RD);

-
#define transpose_4x4(x0, x1, x2, x3, t0, t1, t2) \
vpunpckldq x1, x0, t0; \
vpunpckhdq x1, x0, t2; \
@@ -222,8 +252,8 @@ __twofish_enc_blk_8way:
vmovdqu w(CTX), RK1;

leaq (4*4*4)(%rdx), %rax;
- inpack_blocks(%rdx, RA1, RB1, RC1, RD1, RK1, RX, RY, RK2);
- inpack_blocks(%rax, RA2, RB2, RC2, RD2, RK1, RX, RY, RK2);
+ inpack_blocks(%rdx, RA1, RB1, RC1, RD1, RK1, RX0, RY0, RK2);
+ inpack_blocks(%rax, RA2, RB2, RC2, RD2, RK1, RX0, RY0, RK2);

xorq RID1, RID1;
xorq RID2, RID2;
@@ -247,14 +277,14 @@ __twofish_enc_blk_8way:
testb %cl, %cl;
jnz __enc_xor8;

- outunpack_blocks(%rsi, RC1, RD1, RA1, RB1, RK1, RX, RY, RK2);
- outunpack_blocks(%rax, RC2, RD2, RA2, RB2, RK1, RX, RY, RK2);
+ outunpack_blocks(%rsi, RC1, RD1, RA1, RB1, RK1, RX0, RY0, RK2);
+ outunpack_blocks(%rax, RC2, RD2, RA2, RB2, RK1, RX0, RY0, RK2);

ret;

__enc_xor8:
- outunpack_xor_blocks(%rsi, RC1, RD1, RA1, RB1, RK1, RX, RY, RK2);
- outunpack_xor_blocks(%rax, RC2, RD2, RA2, RB2, RK1, RX, RY, RK2);
+ outunpack_xor_blocks(%rsi, RC1, RD1, RA1, RB1, RK1, RX0, RY0, RK2);
+ outunpack_xor_blocks(%rax, RC2, RD2, RA2, RB2, RK1, RX0, RY0, RK2);

ret;

@@ -274,8 +304,8 @@ twofish_dec_blk_8way:
vmovdqu (w+4*4)(CTX), RK1;

leaq (4*4*4)(%rdx), %rax;
- inpack_blocks(%rdx, RC1, RD1, RA1, RB1, RK1, RX, RY, RK2);
- inpack_blocks(%rax, RC2, RD2, RA2, RB2, RK1, RX, RY, RK2);
+ inpack_blocks(%rdx, RC1, RD1, RA1, RB1, RK1, RX0, RY0, RK2);
+ inpack_blocks(%rax, RC2, RD2, RA2, RB2, RK1, RX0, RY0, RK2);

xorq RID1, RID1;
xorq RID2, RID2;
@@ -294,7 +324,7 @@ twofish_dec_blk_8way:
popq %rbx;

leaq (4*4*4)(%rsi), %rax;
- outunpack_blocks(%rsi, RA1, RB1, RC1, RD1, RK1, RX, RY, RK2);
- outunpack_blocks(%rax, RA2, RB2, RC2, RD2, RK1, RX, RY, RK2);
+ outunpack_blocks(%rsi, RA1, RB1, RC1, RD1, RK1, RX0, RY0, RK2);
+ outunpack_blocks(%rax, RA2, RB2, RC2, RD2, RK1, RX0, RY0, RK2);

ret;

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