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linux/arch/x86/crypto/crct10dif-pcl-asm_64.S
Denys Vlasenko e183914af0 crypto: x86 - make constants readonly, allow linker to merge them 
A lot of asm-optimized routines in arch/x86/crypto/ keep its
constants in .data. This is wrong, they should be on .rodata.

Mnay of these constants are the same in different modules.
For example, 128-bit shuffle mask 0x000102030405060708090A0B0C0D0E0F
exists in at least half a dozen places.

There is a way to let linker merge them and use just one copy.
The rules are as follows: mergeable objects of different sizes
should not share sections. You can't put them all in one .rodata
section, they will lose "mergeability".

GCC puts its mergeable constants in ".rodata.cstSIZE" sections,
or ".rodata.cstSIZE.<object_name>" if -fdata-sections is used.
This patch does the same:

	.section .rodata.cst16.SHUF_MASK, "aM", @progbits, 16

It is important that all data in such section consists of
16-byte elements, not larger ones, and there are no implicit
use of one element from another.

When this is not the case, use non-mergeable section:

	.section .rodata[.VAR_NAME], "a", @progbits

This reduces .data by ~15 kbytes:

    text    data     bss     dec      hex filename
11097415 2705840 2630712 16433967  fac32f vmlinux-prev.o
11112095 2690672 2630712 16433479  fac147 vmlinux.o

Merged objects are visible in System.map:

ffffffff81a28810 r POLY
ffffffff81a28810 r POLY
ffffffff81a28820 r TWOONE
ffffffff81a28820 r TWOONE
ffffffff81a28830 r PSHUFFLE_BYTE_FLIP_MASK <- merged regardless of
ffffffff81a28830 r SHUF_MASK   <------------- the name difference
ffffffff81a28830 r SHUF_MASK
ffffffff81a28830 r SHUF_MASK
..
ffffffff81a28d00 r K512 <- merged three identical 640-byte tables
ffffffff81a28d00 r K512
ffffffff81a28d00 r K512

Use of object names in section name suffixes is not strictly necessary,
but might help if someday link stage will use garbage collection
to eliminate unused sections (ld --gc-sections).

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
CC: Herbert Xu <herbert@gondor.apana.org.au>
CC: Josh Poimboeuf <jpoimboe@redhat.com>
CC: Xiaodong Liu <xiaodong.liu@intel.com>
CC: Megha Dey <megha.dey@intel.com>
CC: linux-crypto@vger.kernel.org
CC: x86@kernel.org
CC: linux-kernel@vger.kernel.org
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-01-23 22:50:29 +08:00

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########################################################################
# Implement fast CRC-T10DIF computation with SSE and PCLMULQDQ instructions
#
# Copyright (c) 2013, Intel Corporation
#
# Authors:
# Erdinc Ozturk <erdinc.ozturk@intel.com>
# Vinodh Gopal <vinodh.gopal@intel.com>
# James Guilford <james.guilford@intel.com>
# Tim Chen <tim.c.chen@linux.intel.com>
#
# This software is available to you under a choice of one of two
# licenses. You may choose to be licensed under the terms of the GNU
# General Public License (GPL) Version 2, available from the file
# COPYING in the main directory of this source tree, or the
# OpenIB.org BSD license below:
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
#
# * Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the
# distribution.
#
# * Neither the name of the Intel Corporation nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
#
#
# THIS SOFTWARE IS PROVIDED BY INTEL CORPORATION ""AS IS"" AND ANY
# EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL INTEL CORPORATION OR
# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
# EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
# PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
# PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
# LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
# NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
########################################################################
# Function API:
# UINT16 crc_t10dif_pcl(
# UINT16 init_crc, //initial CRC value, 16 bits
# const unsigned char *buf, //buffer pointer to calculate CRC on
# UINT64 len //buffer length in bytes (64-bit data)
# );
#
# Reference paper titled "Fast CRC Computation for Generic
# Polynomials Using PCLMULQDQ Instruction"
# URL: http://www.intel.com/content/dam/www/public/us/en/documents
# /white-papers/fast-crc-computation-generic-polynomials-pclmulqdq-paper.pdf
#
#
#include <linux/linkage.h>
.text
#define arg1 %rdi
#define arg2 %rsi
#define arg3 %rdx
#define arg1_low32 %edi
ENTRY(crc_t10dif_pcl)
.align 16
# adjust the 16-bit initial_crc value, scale it to 32 bits
shl $16, arg1_low32
# Allocate Stack Space
mov %rsp, %rcx
sub $16*2, %rsp
# align stack to 16 byte boundary
and $~(0x10 - 1), %rsp
# check if smaller than 256
cmp $256, arg3
# for sizes less than 128, we can't fold 64B at a time...
jl _less_than_128
# load the initial crc value
movd arg1_low32, %xmm10 # initial crc
# crc value does not need to be byte-reflected, but it needs
# to be moved to the high part of the register.
# because data will be byte-reflected and will align with
# initial crc at correct place.
pslldq $12, %xmm10
movdqa SHUF_MASK(%rip), %xmm11
# receive the initial 64B data, xor the initial crc value
movdqu 16*0(arg2), %xmm0
movdqu 16*1(arg2), %xmm1
movdqu 16*2(arg2), %xmm2
movdqu 16*3(arg2), %xmm3
movdqu 16*4(arg2), %xmm4
movdqu 16*5(arg2), %xmm5
movdqu 16*6(arg2), %xmm6
movdqu 16*7(arg2), %xmm7
pshufb %xmm11, %xmm0
# XOR the initial_crc value
pxor %xmm10, %xmm0
pshufb %xmm11, %xmm1
pshufb %xmm11, %xmm2
pshufb %xmm11, %xmm3
pshufb %xmm11, %xmm4
pshufb %xmm11, %xmm5
pshufb %xmm11, %xmm6
pshufb %xmm11, %xmm7
movdqa rk3(%rip), %xmm10 #xmm10 has rk3 and rk4
#imm value of pclmulqdq instruction
#will determine which constant to use
#################################################################
# we subtract 256 instead of 128 to save one instruction from the loop
sub $256, arg3
# at this section of the code, there is 64*x+y (0<=y<64) bytes of
# buffer. The _fold_64_B_loop will fold 64B at a time
# until we have 64+y Bytes of buffer
# fold 64B at a time. This section of the code folds 4 xmm
# registers in parallel
_fold_64_B_loop:
# update the buffer pointer
add $128, arg2 # buf += 64#
movdqu 16*0(arg2), %xmm9
movdqu 16*1(arg2), %xmm12
pshufb %xmm11, %xmm9
pshufb %xmm11, %xmm12
movdqa %xmm0, %xmm8
movdqa %xmm1, %xmm13
pclmulqdq $0x0 , %xmm10, %xmm0
pclmulqdq $0x11, %xmm10, %xmm8
pclmulqdq $0x0 , %xmm10, %xmm1
pclmulqdq $0x11, %xmm10, %xmm13
pxor %xmm9 , %xmm0
xorps %xmm8 , %xmm0
pxor %xmm12, %xmm1
xorps %xmm13, %xmm1
movdqu 16*2(arg2), %xmm9
movdqu 16*3(arg2), %xmm12
pshufb %xmm11, %xmm9
pshufb %xmm11, %xmm12
movdqa %xmm2, %xmm8
movdqa %xmm3, %xmm13
pclmulqdq $0x0, %xmm10, %xmm2
pclmulqdq $0x11, %xmm10, %xmm8
pclmulqdq $0x0, %xmm10, %xmm3
pclmulqdq $0x11, %xmm10, %xmm13
pxor %xmm9 , %xmm2
xorps %xmm8 , %xmm2
pxor %xmm12, %xmm3
xorps %xmm13, %xmm3
movdqu 16*4(arg2), %xmm9
movdqu 16*5(arg2), %xmm12
pshufb %xmm11, %xmm9
pshufb %xmm11, %xmm12
movdqa %xmm4, %xmm8
movdqa %xmm5, %xmm13
pclmulqdq $0x0, %xmm10, %xmm4
pclmulqdq $0x11, %xmm10, %xmm8
pclmulqdq $0x0, %xmm10, %xmm5
pclmulqdq $0x11, %xmm10, %xmm13
pxor %xmm9 , %xmm4
xorps %xmm8 , %xmm4
pxor %xmm12, %xmm5
xorps %xmm13, %xmm5
movdqu 16*6(arg2), %xmm9
movdqu 16*7(arg2), %xmm12
pshufb %xmm11, %xmm9
pshufb %xmm11, %xmm12
movdqa %xmm6 , %xmm8
movdqa %xmm7 , %xmm13
pclmulqdq $0x0 , %xmm10, %xmm6
pclmulqdq $0x11, %xmm10, %xmm8
pclmulqdq $0x0 , %xmm10, %xmm7
pclmulqdq $0x11, %xmm10, %xmm13
pxor %xmm9 , %xmm6
xorps %xmm8 , %xmm6
pxor %xmm12, %xmm7
xorps %xmm13, %xmm7
sub $128, arg3
# check if there is another 64B in the buffer to be able to fold
jge _fold_64_B_loop
##################################################################
add $128, arg2
# at this point, the buffer pointer is pointing at the last y Bytes
# of the buffer the 64B of folded data is in 4 of the xmm
# registers: xmm0, xmm1, xmm2, xmm3
# fold the 8 xmm registers to 1 xmm register with different constants
movdqa rk9(%rip), %xmm10
movdqa %xmm0, %xmm8
pclmulqdq $0x11, %xmm10, %xmm0
pclmulqdq $0x0 , %xmm10, %xmm8
pxor %xmm8, %xmm7
xorps %xmm0, %xmm7
movdqa rk11(%rip), %xmm10
movdqa %xmm1, %xmm8
pclmulqdq $0x11, %xmm10, %xmm1
pclmulqdq $0x0 , %xmm10, %xmm8
pxor %xmm8, %xmm7
xorps %xmm1, %xmm7
movdqa rk13(%rip), %xmm10
movdqa %xmm2, %xmm8
pclmulqdq $0x11, %xmm10, %xmm2
pclmulqdq $0x0 , %xmm10, %xmm8
pxor %xmm8, %xmm7
pxor %xmm2, %xmm7
movdqa rk15(%rip), %xmm10
movdqa %xmm3, %xmm8
pclmulqdq $0x11, %xmm10, %xmm3
pclmulqdq $0x0 , %xmm10, %xmm8
pxor %xmm8, %xmm7
xorps %xmm3, %xmm7
movdqa rk17(%rip), %xmm10
movdqa %xmm4, %xmm8
pclmulqdq $0x11, %xmm10, %xmm4
pclmulqdq $0x0 , %xmm10, %xmm8
pxor %xmm8, %xmm7
pxor %xmm4, %xmm7
movdqa rk19(%rip), %xmm10
movdqa %xmm5, %xmm8
pclmulqdq $0x11, %xmm10, %xmm5
pclmulqdq $0x0 , %xmm10, %xmm8
pxor %xmm8, %xmm7
xorps %xmm5, %xmm7
movdqa rk1(%rip), %xmm10 #xmm10 has rk1 and rk2
#imm value of pclmulqdq instruction
#will determine which constant to use
movdqa %xmm6, %xmm8
pclmulqdq $0x11, %xmm10, %xmm6
pclmulqdq $0x0 , %xmm10, %xmm8
pxor %xmm8, %xmm7
pxor %xmm6, %xmm7
# instead of 64, we add 48 to the loop counter to save 1 instruction
# from the loop instead of a cmp instruction, we use the negative
# flag with the jl instruction
add $128-16, arg3
jl _final_reduction_for_128
# now we have 16+y bytes left to reduce. 16 Bytes is in register xmm7
# and the rest is in memory. We can fold 16 bytes at a time if y>=16
# continue folding 16B at a time
_16B_reduction_loop:
movdqa %xmm7, %xmm8
pclmulqdq $0x11, %xmm10, %xmm7
pclmulqdq $0x0 , %xmm10, %xmm8
pxor %xmm8, %xmm7
movdqu (arg2), %xmm0
pshufb %xmm11, %xmm0
pxor %xmm0 , %xmm7
add $16, arg2
sub $16, arg3
# instead of a cmp instruction, we utilize the flags with the
# jge instruction equivalent of: cmp arg3, 16-16
# check if there is any more 16B in the buffer to be able to fold
jge _16B_reduction_loop
#now we have 16+z bytes left to reduce, where 0<= z < 16.
#first, we reduce the data in the xmm7 register
_final_reduction_for_128:
# check if any more data to fold. If not, compute the CRC of
# the final 128 bits
add $16, arg3
je _128_done
# here we are getting data that is less than 16 bytes.
# since we know that there was data before the pointer, we can
# offset the input pointer before the actual point, to receive
# exactly 16 bytes. after that the registers need to be adjusted.
_get_last_two_xmms:
movdqa %xmm7, %xmm2
movdqu -16(arg2, arg3), %xmm1
pshufb %xmm11, %xmm1
# get rid of the extra data that was loaded before
# load the shift constant
lea pshufb_shf_table+16(%rip), %rax
sub arg3, %rax
movdqu (%rax), %xmm0
# shift xmm2 to the left by arg3 bytes
pshufb %xmm0, %xmm2
# shift xmm7 to the right by 16-arg3 bytes
pxor mask1(%rip), %xmm0
pshufb %xmm0, %xmm7
pblendvb %xmm2, %xmm1 #xmm0 is implicit
# fold 16 Bytes
movdqa %xmm1, %xmm2
movdqa %xmm7, %xmm8
pclmulqdq $0x11, %xmm10, %xmm7
pclmulqdq $0x0 , %xmm10, %xmm8
pxor %xmm8, %xmm7
pxor %xmm2, %xmm7
_128_done:
# compute crc of a 128-bit value
movdqa rk5(%rip), %xmm10 # rk5 and rk6 in xmm10
movdqa %xmm7, %xmm0
#64b fold
pclmulqdq $0x1, %xmm10, %xmm7
pslldq $8 , %xmm0
pxor %xmm0, %xmm7
#32b fold
movdqa %xmm7, %xmm0
pand mask2(%rip), %xmm0
psrldq $12, %xmm7
pclmulqdq $0x10, %xmm10, %xmm7
pxor %xmm0, %xmm7
#barrett reduction
_barrett:
movdqa rk7(%rip), %xmm10 # rk7 and rk8 in xmm10
movdqa %xmm7, %xmm0
pclmulqdq $0x01, %xmm10, %xmm7
pslldq $4, %xmm7
pclmulqdq $0x11, %xmm10, %xmm7
pslldq $4, %xmm7
pxor %xmm0, %xmm7
pextrd $1, %xmm7, %eax
_cleanup:
# scale the result back to 16 bits
shr $16, %eax
mov %rcx, %rsp
ret
########################################################################
.align 16
_less_than_128:
# check if there is enough buffer to be able to fold 16B at a time
cmp $32, arg3
jl _less_than_32
movdqa SHUF_MASK(%rip), %xmm11
# now if there is, load the constants
movdqa rk1(%rip), %xmm10 # rk1 and rk2 in xmm10
movd arg1_low32, %xmm0 # get the initial crc value
pslldq $12, %xmm0 # align it to its correct place
movdqu (arg2), %xmm7 # load the plaintext
pshufb %xmm11, %xmm7 # byte-reflect the plaintext
pxor %xmm0, %xmm7
# update the buffer pointer
add $16, arg2
# update the counter. subtract 32 instead of 16 to save one
# instruction from the loop
sub $32, arg3
jmp _16B_reduction_loop
.align 16
_less_than_32:
# mov initial crc to the return value. this is necessary for
# zero-length buffers.
mov arg1_low32, %eax
test arg3, arg3
je _cleanup
movdqa SHUF_MASK(%rip), %xmm11
movd arg1_low32, %xmm0 # get the initial crc value
pslldq $12, %xmm0 # align it to its correct place
cmp $16, arg3
je _exact_16_left
jl _less_than_16_left
movdqu (arg2), %xmm7 # load the plaintext
pshufb %xmm11, %xmm7 # byte-reflect the plaintext
pxor %xmm0 , %xmm7 # xor the initial crc value
add $16, arg2
sub $16, arg3
movdqa rk1(%rip), %xmm10 # rk1 and rk2 in xmm10
jmp _get_last_two_xmms
.align 16
_less_than_16_left:
# use stack space to load data less than 16 bytes, zero-out
# the 16B in memory first.
pxor %xmm1, %xmm1
mov %rsp, %r11
movdqa %xmm1, (%r11)
cmp $4, arg3
jl _only_less_than_4
# backup the counter value
mov arg3, %r9
cmp $8, arg3
jl _less_than_8_left
# load 8 Bytes
mov (arg2), %rax
mov %rax, (%r11)
add $8, %r11
sub $8, arg3
add $8, arg2
_less_than_8_left:
cmp $4, arg3
jl _less_than_4_left
# load 4 Bytes
mov (arg2), %eax
mov %eax, (%r11)
add $4, %r11
sub $4, arg3
add $4, arg2
_less_than_4_left:
cmp $2, arg3
jl _less_than_2_left
# load 2 Bytes
mov (arg2), %ax
mov %ax, (%r11)
add $2, %r11
sub $2, arg3
add $2, arg2
_less_than_2_left:
cmp $1, arg3
jl _zero_left
# load 1 Byte
mov (arg2), %al
mov %al, (%r11)
_zero_left:
movdqa (%rsp), %xmm7
pshufb %xmm11, %xmm7
pxor %xmm0 , %xmm7 # xor the initial crc value
# shl r9, 4
lea pshufb_shf_table+16(%rip), %rax
sub %r9, %rax
movdqu (%rax), %xmm0
pxor mask1(%rip), %xmm0
pshufb %xmm0, %xmm7
jmp _128_done
.align 16
_exact_16_left:
movdqu (arg2), %xmm7
pshufb %xmm11, %xmm7
pxor %xmm0 , %xmm7 # xor the initial crc value
jmp _128_done
_only_less_than_4:
cmp $3, arg3
jl _only_less_than_3
# load 3 Bytes
mov (arg2), %al
mov %al, (%r11)
mov 1(arg2), %al
mov %al, 1(%r11)
mov 2(arg2), %al
mov %al, 2(%r11)
movdqa (%rsp), %xmm7
pshufb %xmm11, %xmm7
pxor %xmm0 , %xmm7 # xor the initial crc value
psrldq $5, %xmm7
jmp _barrett
_only_less_than_3:
cmp $2, arg3
jl _only_less_than_2
# load 2 Bytes
mov (arg2), %al
mov %al, (%r11)
mov 1(arg2), %al
mov %al, 1(%r11)
movdqa (%rsp), %xmm7
pshufb %xmm11, %xmm7
pxor %xmm0 , %xmm7 # xor the initial crc value
psrldq $6, %xmm7
jmp _barrett
_only_less_than_2:
# load 1 Byte
mov (arg2), %al
mov %al, (%r11)
movdqa (%rsp), %xmm7
pshufb %xmm11, %xmm7
pxor %xmm0 , %xmm7 # xor the initial crc value
psrldq $7, %xmm7
jmp _barrett
ENDPROC(crc_t10dif_pcl)
.section .rodata, "a", @progbits
.align 16
# precomputed constants
# these constants are precomputed from the poly:
# 0x8bb70000 (0x8bb7 scaled to 32 bits)
# Q = 0x18BB70000
# rk1 = 2^(32*3) mod Q << 32
# rk2 = 2^(32*5) mod Q << 32
# rk3 = 2^(32*15) mod Q << 32
# rk4 = 2^(32*17) mod Q << 32
# rk5 = 2^(32*3) mod Q << 32
# rk6 = 2^(32*2) mod Q << 32
# rk7 = floor(2^64/Q)
# rk8 = Q
rk1:
.quad 0x2d56000000000000
rk2:
.quad 0x06df000000000000
rk3:
.quad 0x9d9d000000000000
rk4:
.quad 0x7cf5000000000000
rk5:
.quad 0x2d56000000000000
rk6:
.quad 0x1368000000000000
rk7:
.quad 0x00000001f65a57f8
rk8:
.quad 0x000000018bb70000
rk9:
.quad 0xceae000000000000
rk10:
.quad 0xbfd6000000000000
rk11:
.quad 0x1e16000000000000
rk12:
.quad 0x713c000000000000
rk13:
.quad 0xf7f9000000000000
rk14:
.quad 0x80a6000000000000
rk15:
.quad 0x044c000000000000
rk16:
.quad 0xe658000000000000
rk17:
.quad 0xad18000000000000
rk18:
.quad 0xa497000000000000
rk19:
.quad 0x6ee3000000000000
rk20:
.quad 0xe7b5000000000000
.section .rodata.cst16.mask1, "aM", @progbits, 16
.align 16
mask1:
.octa 0x80808080808080808080808080808080
.section .rodata.cst16.mask2, "aM", @progbits, 16
.align 16
mask2:
.octa 0x00000000FFFFFFFFFFFFFFFFFFFFFFFF
.section .rodata.cst16.SHUF_MASK, "aM", @progbits, 16
.align 16
SHUF_MASK:
.octa 0x000102030405060708090A0B0C0D0E0F
.section .rodata.cst32.pshufb_shf_table, "aM", @progbits, 32
.align 32
pshufb_shf_table:
# use these values for shift constants for the pshufb instruction
# different alignments result in values as shown:
# DDQ 0x008f8e8d8c8b8a898887868584838281 # shl 15 (16-1) / shr1
# DDQ 0x01008f8e8d8c8b8a8988878685848382 # shl 14 (16-3) / shr2
# DDQ 0x0201008f8e8d8c8b8a89888786858483 # shl 13 (16-4) / shr3
# DDQ 0x030201008f8e8d8c8b8a898887868584 # shl 12 (16-4) / shr4
# DDQ 0x04030201008f8e8d8c8b8a8988878685 # shl 11 (16-5) / shr5
# DDQ 0x0504030201008f8e8d8c8b8a89888786 # shl 10 (16-6) / shr6
# DDQ 0x060504030201008f8e8d8c8b8a898887 # shl 9 (16-7) / shr7
# DDQ 0x07060504030201008f8e8d8c8b8a8988 # shl 8 (16-8) / shr8
# DDQ 0x0807060504030201008f8e8d8c8b8a89 # shl 7 (16-9) / shr9
# DDQ 0x090807060504030201008f8e8d8c8b8a # shl 6 (16-10) / shr10
# DDQ 0x0a090807060504030201008f8e8d8c8b # shl 5 (16-11) / shr11
# DDQ 0x0b0a090807060504030201008f8e8d8c # shl 4 (16-12) / shr12
# DDQ 0x0c0b0a090807060504030201008f8e8d # shl 3 (16-13) / shr13
# DDQ 0x0d0c0b0a090807060504030201008f8e # shl 2 (16-14) / shr14
# DDQ 0x0e0d0c0b0a090807060504030201008f # shl 1 (16-15) / shr15
.octa 0x8f8e8d8c8b8a89888786858483828100
.octa 0x000e0d0c0b0a09080706050403020100
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