1 files changed, 232 insertions, 550 deletions

diff --git a/arch/x86/crypto/crct10dif-pcl-asm_64.S b/arch/x86/crypto/crct10dif-pcl-asm_64.S
index de04d3e98d8d..3d873e67749d 100644
--- a/arch/x86/crypto/crct10dif-pcl-asm_64.S
+++ b/arch/x86/crypto/crct10dif-pcl-asm_64.S
@@ -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        arg1_low32 %edi
+#define		init_crc	%edi
+#define		buf		%rsi
+#define		len		%rdx
+
+#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
+ENTRY(crc_t10dif_pcl)
 
-	# 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	.Lbswap_mask(%rip), BSWAP_MASK
+
+	# For sizes less than 256 bytes, we can't fold 128 bytes at a time.
+	cmp	$256, len
+	jl	.Lless_than_256_bytes
+
+	# 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
+
+	# 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
+
+	# Subtract 128 for the 128 data bytes just consumed.  Subtract another
+	# 128 to simplify the termination condition of the following loop.
+	sub	$256, len
+
+	# 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
+
+	# Now fold the 112 bytes in xmm0-xmm6 into the 16 bytes in 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
+
+	# 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
+
+	# 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
-
-	#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:
+	add	$16, buf
+	sub	$16, len
+	jge	.Lfold_16_bytes_loop
+
+.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.
+
 	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
-	movdqa	%xmm7, %xmm0
+.Lreduce_final_16_bytes:
+	# Reduce the 128-bit value M(x), stored in xmm7, to the final 16-bit CRC
 
-	#64b fold
-	pclmulqdq	$0x1, %xmm10, %xmm7
-	pslldq	$8   ,  %xmm0
-	pxor	%xmm0,  %xmm7
+	# Load 'x^48 * (x^48 mod G(x))' and 'x^48 * (x^80 mod G(x))'.
+	movdqa	.Lfinal_fold_consts(%rip), FOLD_CONSTS
 
-	#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
+	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
-
-	psrldq	$12, %xmm7
-	pclmulqdq	$0x10, %xmm10, %xmm7
-	pxor	%xmm0, %xmm7
-
-	#barrett reduction
-_barrett:
-	movdqa	rk7(%rip), %xmm10	# rk7 and rk8 in xmm10
+	# 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
-	pclmulqdq	$0x01, %xmm10, %xmm7
-	pslldq	$4, %xmm7
-	pclmulqdq	$0x11, %xmm10, %xmm7
+	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
 
-	pslldq	$4, %xmm7
-	pxor	%xmm0, %xmm7
-	pextrd	$1, %xmm7, %eax
+	# Load G(x) and floor(x^48 / G(x)).
+	movdqa	.Lbarrett_reduction_consts(%rip), FOLD_CONSTS
 
-_cleanup:
-	# scale the result back to 16 bits
-	shr	$16, %eax
-	mov     %rcx, %rsp
+	# Use Barrett reduction to compute the final CRC value.
+	movdqa	%xmm7, %xmm0
+	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.
+
+	pextrw	$0, %xmm0, %eax
 	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
+.Lless_than_256_bytes:
+	# Checksumming a buffer of length 16...255 bytes
 
-	# now if there is, load the constants
-	movdqa	rk1(%rip), %xmm10	# rk1 and rk2 in xmm10
+	# Load the first 16 data bytes.
+	movdqu	(buf), %xmm7
+	pshufb	BSWAP_MASK, %xmm7
+	add	$16, buf
 
-	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.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
-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
+# 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