Skip to content

L
linux
Commit 0974037f authored by Eric Biggers's avatar Eric Biggers Committed by Herbert Xu
Browse files
Options

crypto: x86/crct10dif-pcl - cleanup and optimizations 

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: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent f8903b3e
Hide whitespace changes
Inline Side-by-side
Showing with 235 additions and 559 deletions
arch/x86/crypto/crct10dif-pcl-asm_64.S
View file @ 0974037f
...@@ -43,609 +43,291 @@ ...@@ -43,609 +43,291 @@
# LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING # LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
# NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS # NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. # 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 # Reference paper titled "Fast CRC Computation for Generic
# Polynomials Using PCLMULQDQ Instruction" # Polynomials Using PCLMULQDQ Instruction"
# URL: http://www.intel.com/content/dam/www/public/us/en/documents # URL: http://www.intel.com/content/dam/www/public/us/en/documents
# /white-papers/fast-crc-computation-generic-polynomials-pclmulqdq-paper.pdf # /white-papers/fast-crc-computation-generic-polynomials-pclmulqdq-paper.pdf
# #
#
#include <linux/linkage.h> #include <linux/linkage.h>
.text .text
#define arg1 %rdi #define init_crc %edi
#define arg2 %rsi #define buf %rsi
#define arg3 %rdx #define len %rdx
#define arg1_low32 %edi #define FOLD_CONSTS %xmm10
#define BSWAP_MASK %xmm11
# 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
ENTRY(crc_t10dif_pcl) #
# u16 crc_t10dif_pcl(u16 init_crc, const *u8 buf, size_t len);
#
# Assumes len >= 16.
#
.align 16 .align 16
ENTRY(crc_t10dif_pcl)
# adjust the 16-bit initial_crc value, scale it to 32 bits movdqa .Lbswap_mask(%rip), BSWAP_MASK
shl $16, arg1_low32
# For sizes less than 256 bytes, we can't fold 128 bytes at a time.
# Allocate Stack Space cmp $256, len
mov %rsp, %rcx jl .Lless_than_256_bytes
sub $16*2, %rsp
# align stack to 16 byte boundary # Load the first 128 data bytes. Byte swapping is necessary to make the
and $~(0x10 - 1), %rsp # bit order match the polynomial coefficient order.
movdqu 16*0(buf), %xmm0
# check if smaller than 256 movdqu 16*1(buf), %xmm1
cmp $256, arg3 movdqu 16*2(buf), %xmm2
movdqu 16*3(buf), %xmm3
# for sizes less than 128, we can't fold 64B at a time... movdqu 16*4(buf), %xmm4
jl _less_than_128 movdqu 16*5(buf), %xmm5
movdqu 16*6(buf), %xmm6
movdqu 16*7(buf), %xmm7
# load the initial crc value add $128, buf
movd arg1_low32, %xmm10 # initial crc pshufb BSWAP_MASK, %xmm0
pshufb BSWAP_MASK, %xmm1
# crc value does not need to be byte-reflected, but it needs pshufb BSWAP_MASK, %xmm2
# to be moved to the high part of the register. pshufb BSWAP_MASK, %xmm3
# because data will be byte-reflected and will align with pshufb BSWAP_MASK, %xmm4
# initial crc at correct place. pshufb BSWAP_MASK, %xmm5
pslldq $12, %xmm10 pshufb BSWAP_MASK, %xmm6
pshufb BSWAP_MASK, %xmm7
movdqa SHUF_MASK(%rip), %xmm11
# receive the initial 64B data, xor the initial crc value # XOR the first 16 data *bits* with the initial CRC value.
movdqu 16*0(arg2), %xmm0 pxor %xmm8, %xmm8
movdqu 16*1(arg2), %xmm1 pinsrw $7, init_crc, %xmm8
movdqu 16*2(arg2), %xmm2 pxor %xmm8, %xmm0
movdqu 16*3(arg2), %xmm3
movdqu 16*4(arg2), %xmm4 movdqa .Lfold_across_128_bytes_consts(%rip), FOLD_CONSTS
movdqu 16*5(arg2), %xmm5
movdqu 16*6(arg2), %xmm6 # Subtract 128 for the 128 data bytes just consumed. Subtract another
movdqu 16*7(arg2), %xmm7 # 128 to simplify the termination condition of the following loop.
sub $256, len
pshufb %xmm11, %xmm0
# XOR the initial_crc value # While >= 128 data bytes remain (not counting xmm0-7), fold the 128
pxor %xmm10, %xmm0 # bytes xmm0-7 into them, storing the result back into xmm0-7.
pshufb %xmm11, %xmm1 .Lfold_128_bytes_loop:
pshufb %xmm11, %xmm2 fold_32_bytes 0, %xmm0, %xmm1
pshufb %xmm11, %xmm3 fold_32_bytes 32, %xmm2, %xmm3
pshufb %xmm11, %xmm4 fold_32_bytes 64, %xmm4, %xmm5
pshufb %xmm11, %xmm5 fold_32_bytes 96, %xmm6, %xmm7
pshufb %xmm11, %xmm6 add $128, buf
pshufb %xmm11, %xmm7 sub $128, len
jge .Lfold_128_bytes_loop
movdqa rk3(%rip), %xmm10 #xmm10 has rk3 and rk4
#imm value of pclmulqdq instruction # Now fold the 112 bytes in xmm0-xmm6 into the 16 bytes in xmm7.
#will determine which constant to use
# Fold across 64 bytes.
################################################################# movdqa .Lfold_across_64_bytes_consts(%rip), FOLD_CONSTS
# we subtract 256 instead of 128 to save one instruction from the loop fold_16_bytes %xmm0, %xmm4
sub $256, arg3 fold_16_bytes %xmm1, %xmm5
fold_16_bytes %xmm2, %xmm6
# at this section of the code, there is 64*x+y (0<=y<64) bytes of fold_16_bytes %xmm3, %xmm7
# buffer. The _fold_64_B_loop will fold 64B at a time # Fold across 32 bytes.
# until we have 64+y Bytes of buffer movdqa .Lfold_across_32_bytes_consts(%rip), FOLD_CONSTS
fold_16_bytes %xmm4, %xmm6
fold_16_bytes %xmm5, %xmm7
# fold 64B at a time. This section of the code folds 4 xmm # Fold across 16 bytes.
# registers in parallel movdqa .Lfold_across_16_bytes_consts(%rip), FOLD_CONSTS
_fold_64_B_loop: fold_16_bytes %xmm6, %xmm7
# update the buffer pointer # Add 128 to get the correct number of data bytes remaining in 0...127
add $128, arg2 # buf += 64# # (not counting xmm7), following the previous extra subtraction by 128.
# Then subtract 16 to simplify the termination condition of the
movdqu 16*0(arg2), %xmm9 # following loop.
movdqu 16*1(arg2), %xmm12 add $128-16, len
pshufb %xmm11, %xmm9
pshufb %xmm11, %xmm12 # While >= 16 data bytes remain (not counting xmm7), fold the 16 bytes
movdqa %xmm0, %xmm8 # xmm7 into them, storing the result back into xmm7.
movdqa %xmm1, %xmm13 jl .Lfold_16_bytes_loop_done
pclmulqdq $0x0 , %xmm10, %xmm0 .Lfold_16_bytes_loop:
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 movdqa %xmm7, %xmm8
pclmulqdq $0x11, %xmm10, %xmm7 pclmulqdq $0x11, FOLD_CONSTS, %xmm7
pclmulqdq $0x0 , %xmm10, %xmm8 pclmulqdq $0x00, FOLD_CONSTS, %xmm8
pxor %xmm8, %xmm7 pxor %xmm8, %xmm7
movdqu (arg2), %xmm0 movdqu (buf), %xmm0
pshufb %xmm11, %xmm0 pshufb BSWAP_MASK, %xmm0
pxor %xmm0 , %xmm7 pxor %xmm0 , %xmm7
add $16, arg2 add $16, buf
sub $16, arg3 sub $16, len
# instead of a cmp instruction, we utilize the flags with the jge .Lfold_16_bytes_loop
# jge instruction equivalent of: cmp arg3, 16-16
# check if there is any more 16B in the buffer to be able to fold .Lfold_16_bytes_loop_done:
jge _16B_reduction_loop # Add 16 to get the correct number of data bytes remaining in 0...15
# (not counting xmm7), following the previous extra subtraction by 16.
#now we have 16+z bytes left to reduce, where 0<= z < 16. add $16, len
#first, we reduce the data in the xmm7 register je .Lreduce_final_16_bytes
.Lhandle_partial_segment:
_final_reduction_for_128: # Reduce the last '16 + len' bytes where 1 <= len <= 15 and the first 16
# check if any more data to fold. If not, compute the CRC of # bytes are in xmm7 and the rest are the remaining data in 'buf'. To do
# the final 128 bits # this without needing a fold constant for each possible 'len', redivide
add $16, arg3 # the bytes into a first chunk of 'len' bytes and a second chunk of 16
je _128_done # bytes, then fold the first chunk into the second.
# 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 movdqa %xmm7, %xmm2
movdqu -16(arg2, arg3), %xmm1 # xmm1 = last 16 original data bytes
pshufb %xmm11, %xmm1 movdqu -16(buf, len), %xmm1
pshufb BSWAP_MASK, %xmm1
# get rid of the extra data that was loaded before # xmm2 = high order part of second chunk: xmm7 left-shifted by 'len' bytes.
# load the shift constant lea .Lbyteshift_table+16(%rip), %rax
lea pshufb_shf_table+16(%rip), %rax sub len, %rax
sub arg3, %rax
movdqu (%rax), %xmm0 movdqu (%rax), %xmm0
# shift xmm2 to the left by arg3 bytes
pshufb %xmm0, %xmm2 pshufb %xmm0, %xmm2
# shift xmm7 to the right by 16-arg3 bytes # xmm7 = first chunk: xmm7 right-shifted by '16-len' bytes.
pxor mask1(%rip), %xmm0 pxor .Lmask1(%rip), %xmm0
pshufb %xmm0, %xmm7 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 pblendvb %xmm2, %xmm1 #xmm0 is implicit
# fold 16 Bytes # Fold the first chunk into the second chunk, storing the result in xmm7.
movdqa %xmm1, %xmm2
movdqa %xmm7, %xmm8 movdqa %xmm7, %xmm8
pclmulqdq $0x11, %xmm10, %xmm7 pclmulqdq $0x11, FOLD_CONSTS, %xmm7
pclmulqdq $0x0 , %xmm10, %xmm8 pclmulqdq $0x00, FOLD_CONSTS, %xmm8
pxor %xmm8, %xmm7 pxor %xmm8, %xmm7
pxor %xmm2, %xmm7 pxor %xmm1, %xmm7
_128_done: .Lreduce_final_16_bytes:
# compute crc of a 128-bit value # Reduce the 128-bit value M(x), stored in xmm7, to the final 16-bit CRC
movdqa rk5(%rip), %xmm10 # rk5 and rk6 in xmm10
movdqa %xmm7, %xmm0
#64b fold # Load 'x^48 * (x^48 mod G(x))' and 'x^48 * (x^80 mod G(x))'.
pclmulqdq $0x1, %xmm10, %xmm7 movdqa .Lfinal_fold_consts(%rip), FOLD_CONSTS
pslldq $8 , %xmm0
pxor %xmm0, %xmm7
#32b fold # 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 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
pand mask2(%rip), %xmm0 # 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.
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 movdqa %xmm7, %xmm0
pclmulqdq $0x01, %xmm10, %xmm7 pand .Lmask2(%rip), %xmm0 # zero high 32 bits
pslldq $4, %xmm7 psrldq $12, %xmm7 # extract high 32 bits
pclmulqdq $0x11, %xmm10, %xmm7 pclmulqdq $0x00, FOLD_CONSTS, %xmm7 # high 32 bits * x^48 * (x^48 mod G(x))
pxor %xmm0, %xmm7 # + low bits
pslldq $4, %xmm7 # Load G(x) and floor(x^48 / G(x)).
pxor %xmm0, %xmm7 movdqa .Lbarrett_reduction_consts(%rip), FOLD_CONSTS
pextrd $1, %xmm7, %eax
_cleanup: # Use Barrett reduction to compute the final CRC value.
# scale the result back to 16 bits movdqa %xmm7, %xmm0
shr $16, %eax pclmulqdq $0x11, FOLD_CONSTS, %xmm7 # high 32 bits * floor(x^48 / G(x))
mov %rcx, %rsp 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.
pextrw $0, %xmm0, %eax
ret ret
########################################################################
.align 16 .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
# now if there is, load the constants # Load the first 16 data bytes.
movdqa rk1(%rip), %xmm10 # rk1 and rk2 in xmm10 movdqu (buf), %xmm7
pshufb BSWAP_MASK, %xmm7
add $16, buf
movd arg1_low32, %xmm0 # get the initial crc value # XOR the first 16 data *bits* with the initial CRC value.
pslldq $12, %xmm0 # align it to its correct place pxor %xmm0, %xmm0
movdqu (arg2), %xmm7 # load the plaintext pinsrw $7, init_crc, %xmm0
pshufb %xmm11, %xmm7 # byte-reflect the plaintext
pxor %xmm0, %xmm7 pxor %xmm0, %xmm7
movdqa .Lfold_across_16_bytes_consts(%rip), FOLD_CONSTS
# update the buffer pointer cmp $16, len
add $16, arg2 je .Lreduce_final_16_bytes # len == 16
sub $32, len
# update the counter. subtract 32 instead of 16 to save one jge .Lfold_16_bytes_loop # 32 <= len <= 255
# instruction from the loop add $16, len
sub $32, arg3 jmp .Lhandle_partial_segment # 17 <= len <= 31
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) ENDPROC(crc_t10dif_pcl)
.section .rodata, "a", @progbits .section .rodata, "a", @progbits
.align 16 .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 .section .rodata.cst16.mask1, "aM", @progbits, 16
.align 16 .align 16
mask1: .Lmask1:
.octa 0x80808080808080808080808080808080 .octa 0x80808080808080808080808080808080
.section .rodata.cst16.mask2, "aM", @progbits, 16 .section .rodata.cst16.mask2, "aM", @progbits, 16
.align 16 .align 16
mask2: .Lmask2:
.octa 0x00000000FFFFFFFFFFFFFFFFFFFFFFFF .octa 0x00000000FFFFFFFFFFFFFFFFFFFFFFFF
.section .rodata.cst16.bswap_mask, "aM", @progbits, 16
.align 16
.Lbswap_mask:
.octa 0x000102030405060708090A0B0C0D0E0F
.section .rodata.cst16.SHUF_MASK, "aM", @progbits, 16 .section .rodata.cst32.byteshift_table, "aM", @progbits, 32
.align 16 .align 16
SHUF_MASK: # For 1 <= len <= 15, the 16-byte vector beginning at &byteshift_table[16 - len]
.octa 0x000102030405060708090A0B0C0D0E0F # 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.
.section .rodata.cst32.pshufb_shf_table, "aM", @progbits, 32 .Lbyteshift_table:
.align 32 .byte 0x0, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87
pshufb_shf_table: .byte 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f
# use these values for shift constants for the pshufb instruction .byte 0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7
# different alignments result in values as shown: .byte 0x8, 0x9, 0xa, 0xb, 0xc, 0xd, 0xe , 0x0
# 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
arch/x86/crypto/crct10dif-pclmul_glue.c
View file @ 0974037f
...@@ -33,18 +33,12 @@ ...@@ -33,18 +33,12 @@
#include <asm/cpufeatures.h> #include <asm/cpufeatures.h>
#include <asm/cpu_device_id.h> #include <asm/cpu_device_id.h>
asmlinkage __u16 crc_t10dif_pcl(__u16 crc, const unsigned char *buf, asmlinkage u16 crc_t10dif_pcl(u16 init_crc, const u8 *buf, size_t len);
size_t len);
struct chksum_desc_ctx { struct chksum_desc_ctx {
__u16 crc; __u16 crc;
}; };
/*
* Steps through buffer one byte at at time, calculates reflected
* crc using table.
*/
static int chksum_init(struct shash_desc *desc) static int chksum_init(struct shash_desc *desc)
{ {
struct chksum_desc_ctx *ctx = shash_desc_ctx(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, ...@@ -59,7 +53,7 @@ static int chksum_update(struct shash_desc *desc, const u8 *data,
{ {
struct chksum_desc_ctx *ctx = shash_desc_ctx(desc); struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
if (irq_fpu_usable()) { if (length >= 16 && irq_fpu_usable()) {
kernel_fpu_begin(); kernel_fpu_begin();
ctx->crc = crc_t10dif_pcl(ctx->crc, data, length); ctx->crc = crc_t10dif_pcl(ctx->crc, data, length);
kernel_fpu_end(); kernel_fpu_end();
...@@ -79,7 +73,7 @@ static int chksum_final(struct shash_desc *desc, u8 *out) ...@@ -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, static int __chksum_finup(__u16 *crcp, const u8 *data, unsigned int len,
u8 *out) u8 *out)
{ {
if (irq_fpu_usable()) { if (len >= 16 && irq_fpu_usable()) {
kernel_fpu_begin(); kernel_fpu_begin();
*(__u16 *)out = crc_t10dif_pcl(*crcp, data, len); *(__u16 *)out = crc_t10dif_pcl(*crcp, data, len);
kernel_fpu_end(); kernel_fpu_end();
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7