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crypto: x86/crct10dif-pcl - cleanup and optimizations

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The x86, arm, and arm64 asm implementations of crct10dif are very
difficult to understand partly because many of the comments, labels, and
macros are named incorrectly: the lengths mentioned are usually off by a
factor of two from the actual code.  Many other things are unnecessarily
convoluted as well, e.g. there are many more fold constants than
actually needed and some aren't fully reduced.

This series therefore cleans up all these implementations to be much
more maintainable.  I also made some small optimizations where I saw
opportunities, resulting in slightly better performance.

This patch cleans up the x86 version.

As part of this, I removed support for len < 16 from the x86 assembly;
now the glue code falls back to the generic table-based implementation
in this case.  Due to the overhead of kernel_fpu_begin(), this actually
significantly improves performance on these lengths.  (And even if
kernel_fpu_begin() were free, the generic code is still faster for about
len < 11.)  This removal also eliminates error-prone special cases and
makes the x86, arm32, and arm64 ports of the code match more closely.

Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Eric Biggers 2019-01-30 20:42:40 -08:00 committed by Herbert Xu
parent f8903b3ead
commit 0974037fc5
2 changed files with 220 additions and 544 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

752
arch/x86/crypto/crct10dif-pcl-asm_64.S
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@ -43,609 +43,291 @@
# 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 init_crc %edi
#define buf %rsi
#define len %rdx
#define arg1_low32 %edi
#define FOLD_CONSTS %xmm10
#define BSWAP_MASK %xmm11
ENTRY(crc_t10dif_pcl)
# Fold reg1, reg2 into the next 32 data bytes, storing the result back into
# reg1, reg2.
.macro fold_32_bytes offset, reg1, reg2
movdqu \offset(buf), %xmm9
movdqu \offset+16(buf), %xmm12
pshufb BSWAP_MASK, %xmm9
pshufb BSWAP_MASK, %xmm12
movdqa \reg1, %xmm8
movdqa \reg2, %xmm13
pclmulqdq $0x00, FOLD_CONSTS, \reg1
pclmulqdq $0x11, FOLD_CONSTS, %xmm8
pclmulqdq $0x00, FOLD_CONSTS, \reg2
pclmulqdq $0x11, FOLD_CONSTS, %xmm13
pxor %xmm9 , \reg1
xorps %xmm8 , \reg1
pxor %xmm12, \reg2
xorps %xmm13, \reg2
.endm
# Fold src_reg into dst_reg.
.macro fold_16_bytes src_reg, dst_reg
movdqa \src_reg, %xmm8
pclmulqdq $0x11, FOLD_CONSTS, \src_reg
pclmulqdq $0x00, FOLD_CONSTS, %xmm8
pxor %xmm8, \dst_reg
xorps \src_reg, \dst_reg
.endm
#
# u16 crc_t10dif_pcl(u16 init_crc, const *u8 buf, size_t len);
#
# Assumes len >= 16.
#
.align 16
ENTRY(crc_t10dif_pcl)
# adjust the 16-bit initial_crc value, scale it to 32 bits
shl $16, arg1_low32
movdqa .Lbswap_mask(%rip), BSWAP_MASK
# Allocate Stack Space
mov %rsp, %rcx
sub $16*2, %rsp
# align stack to 16 byte boundary
and $~(0x10 - 1), %rsp
# For sizes less than 256 bytes, we can't fold 128 bytes at a time.
cmp $256, len
jl .Lless_than_256_bytes
# check if smaller than 256
cmp $256, arg3
# Load the first 128 data bytes. Byte swapping is necessary to make the
# bit order match the polynomial coefficient order.
movdqu 16*0(buf), %xmm0
movdqu 16*1(buf), %xmm1
movdqu 16*2(buf), %xmm2
movdqu 16*3(buf), %xmm3
movdqu 16*4(buf), %xmm4
movdqu 16*5(buf), %xmm5
movdqu 16*6(buf), %xmm6
movdqu 16*7(buf), %xmm7
add $128, buf
pshufb BSWAP_MASK, %xmm0
pshufb BSWAP_MASK, %xmm1
pshufb BSWAP_MASK, %xmm2
pshufb BSWAP_MASK, %xmm3
pshufb BSWAP_MASK, %xmm4
pshufb BSWAP_MASK, %xmm5
pshufb BSWAP_MASK, %xmm6
pshufb BSWAP_MASK, %xmm7
# for sizes less than 128, we can't fold 64B at a time...
jl _less_than_128
# XOR the first 16 data *bits* with the initial CRC value.
pxor %xmm8, %xmm8
pinsrw $7, init_crc, %xmm8
pxor %xmm8, %xmm0
movdqa .Lfold_across_128_bytes_consts(%rip), FOLD_CONSTS
# load the initial crc value
movd arg1_low32, %xmm10 # initial crc
# Subtract 128 for the 128 data bytes just consumed. Subtract another
# 128 to simplify the termination condition of the following loop.
sub $256, len
# 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
# While >= 128 data bytes remain (not counting xmm0-7), fold the 128
# bytes xmm0-7 into them, storing the result back into xmm0-7.
.Lfold_128_bytes_loop:
fold_32_bytes 0, %xmm0, %xmm1
fold_32_bytes 32, %xmm2, %xmm3
fold_32_bytes 64, %xmm4, %xmm5
fold_32_bytes 96, %xmm6, %xmm7
add $128, buf
sub $128, len
jge .Lfold_128_bytes_loop
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
# Now fold the 112 bytes in xmm0-xmm6 into the 16 bytes in 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
# Fold across 64 bytes.
movdqa .Lfold_across_64_bytes_consts(%rip), FOLD_CONSTS
fold_16_bytes %xmm0, %xmm4
fold_16_bytes %xmm1, %xmm5
fold_16_bytes %xmm2, %xmm6
fold_16_bytes %xmm3, %xmm7
# Fold across 32 bytes.
movdqa .Lfold_across_32_bytes_consts(%rip), FOLD_CONSTS
fold_16_bytes %xmm4, %xmm6
fold_16_bytes %xmm5, %xmm7
# Fold across 16 bytes.
movdqa .Lfold_across_16_bytes_consts(%rip), FOLD_CONSTS
fold_16_bytes %xmm6, %xmm7
movdqa rk3(%rip), %xmm10 #xmm10 has rk3 and rk4
#imm value of pclmulqdq instruction
#will determine which constant to use
# Add 128 to get the correct number of data bytes remaining in 0...127
# (not counting xmm7), following the previous extra subtraction by 128.
# Then subtract 16 to simplify the termination condition of the
# following loop.
add $128-16, len
#################################################################
# 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:
# While >= 16 data bytes remain (not counting xmm7), fold the 16 bytes
# xmm7 into them, storing the result back into xmm7.
jl .Lfold_16_bytes_loop_done
.Lfold_16_bytes_loop:
movdqa %xmm7, %xmm8
pclmulqdq $0x11, %xmm10, %xmm7
pclmulqdq $0x0 , %xmm10, %xmm8
pclmulqdq $0x11, FOLD_CONSTS, %xmm7
pclmulqdq $0x00, FOLD_CONSTS, %xmm8
pxor %xmm8, %xmm7
movdqu (arg2), %xmm0
pshufb %xmm11, %xmm0
movdqu (buf), %xmm0
pshufb BSWAP_MASK, %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
add $16, buf
sub $16, len
jge .Lfold_16_bytes_loop
#now we have 16+z bytes left to reduce, where 0<= z < 16.
#first, we reduce the data in the xmm7 register
.Lfold_16_bytes_loop_done:
# Add 16 to get the correct number of data bytes remaining in 0...15
# (not counting xmm7), following the previous extra subtraction by 16.
add $16, len
je .Lreduce_final_16_bytes
.Lhandle_partial_segment:
# Reduce the last '16 + len' bytes where 1 <= len <= 15 and the first 16
# bytes are in xmm7 and the rest are the remaining data in 'buf'. To do
# this without needing a fold constant for each possible 'len', redivide
# the bytes into a first chunk of 'len' bytes and a second chunk of 16
# bytes, then fold the first chunk into the second.
_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
# xmm1 = last 16 original data bytes
movdqu -16(buf, len), %xmm1
pshufb BSWAP_MASK, %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
# xmm2 = high order part of second chunk: xmm7 left-shifted by 'len' bytes.
lea .Lbyteshift_table+16(%rip), %rax
sub len, %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
# xmm7 = first chunk: xmm7 right-shifted by '16-len' bytes.
pxor .Lmask1(%rip), %xmm0
pshufb %xmm0, %xmm7
# xmm1 = second chunk: 'len' bytes from xmm1 (low-order bytes),
# then '16-len' bytes from xmm2 (high-order bytes).
pblendvb %xmm2, %xmm1 #xmm0 is implicit
# fold 16 Bytes
movdqa %xmm1, %xmm2
# Fold the first chunk into the second chunk, storing the result in xmm7.
movdqa %xmm7, %xmm8
pclmulqdq $0x11, %xmm10, %xmm7
pclmulqdq $0x0 , %xmm10, %xmm8
pclmulqdq $0x11, FOLD_CONSTS, %xmm7
pclmulqdq $0x00, FOLD_CONSTS, %xmm8
pxor %xmm8, %xmm7
pxor %xmm2, %xmm7
pxor %xmm1, %xmm7
_128_done:
# compute crc of a 128-bit value
movdqa rk5(%rip), %xmm10 # rk5 and rk6 in xmm10
.Lreduce_final_16_bytes:
# Reduce the 128-bit value M(x), stored in xmm7, to the final 16-bit CRC
# Load 'x^48 * (x^48 mod G(x))' and 'x^48 * (x^80 mod G(x))'.
movdqa .Lfinal_fold_consts(%rip), FOLD_CONSTS
# Fold the high 64 bits into the low 64 bits, while also multiplying by
# x^64. This produces a 128-bit value congruent to x^64 * M(x) and
# whose low 48 bits are 0.
movdqa %xmm7, %xmm0
pclmulqdq $0x11, FOLD_CONSTS, %xmm7 # high bits * x^48 * (x^80 mod G(x))
pslldq $8, %xmm0
pxor %xmm0, %xmm7 # + low bits * x^64
#64b fold
pclmulqdq $0x1, %xmm10, %xmm7
pslldq $8 , %xmm0
pxor %xmm0, %xmm7
#32b fold
# Fold the high 32 bits into the low 96 bits. This produces a 96-bit
# value congruent to x^64 * M(x) and whose low 48 bits are 0.
movdqa %xmm7, %xmm0
pand .Lmask2(%rip), %xmm0 # zero high 32 bits
psrldq $12, %xmm7 # extract high 32 bits
pclmulqdq $0x00, FOLD_CONSTS, %xmm7 # high 32 bits * x^48 * (x^48 mod G(x))
pxor %xmm0, %xmm7 # + low bits
pand mask2(%rip), %xmm0
# Load G(x) and floor(x^48 / G(x)).
movdqa .Lbarrett_reduction_consts(%rip), FOLD_CONSTS
psrldq $12, %xmm7
pclmulqdq $0x10, %xmm10, %xmm7
pxor %xmm0, %xmm7
#barrett reduction
_barrett:
movdqa rk7(%rip), %xmm10 # rk7 and rk8 in xmm10
# Use Barrett reduction to compute the final CRC value.
movdqa %xmm7, %xmm0
pclmulqdq $0x01, %xmm10, %xmm7
pslldq $4, %xmm7
pclmulqdq $0x11, %xmm10, %xmm7
pclmulqdq $0x11, FOLD_CONSTS, %xmm7 # high 32 bits * floor(x^48 / G(x))
psrlq $32, %xmm7 # /= x^32
pclmulqdq $0x00, FOLD_CONSTS, %xmm7 # *= G(x)
psrlq $48, %xmm0
pxor %xmm7, %xmm0 # + low 16 nonzero bits
# Final CRC value (x^16 * M(x)) mod G(x) is in low 16 bits of xmm0.
pslldq $4, %xmm7
pxor %xmm0, %xmm7
pextrd $1, %xmm7, %eax
_cleanup:
# scale the result back to 16 bits
shr $16, %eax
mov %rcx, %rsp
pextrw $0, %xmm0, %eax
ret
########################################################################
.align 16
_less_than_128:
.Lless_than_256_bytes:
# Checksumming a buffer of length 16...255 bytes
# 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
# Load the first 16 data bytes.
movdqu (buf), %xmm7
pshufb BSWAP_MASK, %xmm7
add $16, buf
# 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
# XOR the first 16 data *bits* with the initial CRC value.
pxor %xmm0, %xmm0
pinsrw $7, init_crc, %xmm0
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
movdqa .Lfold_across_16_bytes_consts(%rip), FOLD_CONSTS
cmp $16, len
je .Lreduce_final_16_bytes # len == 16
sub $32, len
jge .Lfold_16_bytes_loop # 32 <= len <= 255
add $16, len
jmp .Lhandle_partial_segment # 17 <= len <= 31
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
# Fold constants precomputed from the polynomial 0x18bb7
# G(x) = x^16 + x^15 + x^11 + x^9 + x^8 + x^7 + x^5 + x^4 + x^2 + x^1 + x^0
.Lfold_across_128_bytes_consts:
.quad 0x0000000000006123 # x^(8*128) mod G(x)
.quad 0x0000000000002295 # x^(8*128+64) mod G(x)
.Lfold_across_64_bytes_consts:
.quad 0x0000000000001069 # x^(4*128) mod G(x)
.quad 0x000000000000dd31 # x^(4*128+64) mod G(x)
.Lfold_across_32_bytes_consts:
.quad 0x000000000000857d # x^(2*128) mod G(x)
.quad 0x0000000000007acc # x^(2*128+64) mod G(x)
.Lfold_across_16_bytes_consts:
.quad 0x000000000000a010 # x^(1*128) mod G(x)
.quad 0x0000000000001faa # x^(1*128+64) mod G(x)
.Lfinal_fold_consts:
.quad 0x1368000000000000 # x^48 * (x^48 mod G(x))
.quad 0x2d56000000000000 # x^48 * (x^80 mod G(x))
.Lbarrett_reduction_consts:
.quad 0x0000000000018bb7 # G(x)
.quad 0x00000001f65a57f8 # floor(x^48 / G(x))
.section .rodata.cst16.mask1, "aM", @progbits, 16
.align 16
mask1:
.octa 0x80808080808080808080808080808080
.Lmask1:
.octa 0x80808080808080808080808080808080
.section .rodata.cst16.mask2, "aM", @progbits, 16
.align 16
mask2:
.octa 0x00000000FFFFFFFFFFFFFFFFFFFFFFFF
.Lmask2:
.octa 0x00000000FFFFFFFFFFFFFFFFFFFFFFFF
.section .rodata.cst16.SHUF_MASK, "aM", @progbits, 16
.section .rodata.cst16.bswap_mask, "aM", @progbits, 16
.align 16
SHUF_MASK:
.octa 0x000102030405060708090A0B0C0D0E0F
.Lbswap_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
.section .rodata.cst32.byteshift_table, "aM", @progbits, 32
.align 16
# For 1 <= len <= 15, the 16-byte vector beginning at &byteshift_table[16 - len]
# is the index vector to shift left by 'len' bytes, and is also {0x80, ...,
# 0x80} XOR the index vector to shift right by '16 - len' bytes.
.Lbyteshift_table:
.byte 0x0, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87
.byte 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f
.byte 0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7
.byte 0x8, 0x9, 0xa, 0xb, 0xc, 0xd, 0xe , 0x0

12
arch/x86/crypto/crct10dif-pclmul_glue.c
View File

@ -33,18 +33,12 @@
#include <asm/cpufeatures.h>
#include <asm/cpu_device_id.h>
asmlinkage __u16 crc_t10dif_pcl(__u16 crc, const unsigned char *buf,
size_t len);
asmlinkage u16 crc_t10dif_pcl(u16 init_crc, const u8 *buf, size_t len);
struct chksum_desc_ctx {
__u16 crc;
};
/*
* Steps through buffer one byte at at time, calculates reflected
* crc using table.
*/
static int chksum_init(struct shash_desc *desc)
{
struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
@ -59,7 +53,7 @@ static int chksum_update(struct shash_desc *desc, const u8 *data,
{
struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
if (irq_fpu_usable()) {
if (length >= 16 && irq_fpu_usable()) {
kernel_fpu_begin();
ctx->crc = crc_t10dif_pcl(ctx->crc, data, length);
kernel_fpu_end();
@ -79,7 +73,7 @@ static int chksum_final(struct shash_desc *desc, u8 *out)
static int __chksum_finup(__u16 *crcp, const u8 *data, unsigned int len,
u8 *out)
{
if (irq_fpu_usable()) {
if (len >= 16 && irq_fpu_usable()) {
kernel_fpu_begin();
*(__u16 *)out = crc_t10dif_pcl(*crcp, data, len);
kernel_fpu_end();