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alistair23-linux/arch/xtensa/lib/checksum.S
Max Filippov d6d5f19e21 xtensa: abstract 'entry' and 'retw' in assembly code 
Provide abi_entry, abi_entry_default, abi_ret and abi_ret_default macros
that allocate aligned stack frame in windowed and call0 ABIs.
Provide XTENSA_SPILL_STACK_RESERVE macro that specifies required stack
frame size when register spilling is involved.
Replace all uses of 'entry' and 'retw' with the above macros.
This makes most of the xtensa assembly code ready for XEA3 and call0 ABI.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
2019-07-08 10:04:48 -07:00

395 lines
8.5 KiB
ArmAsm
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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* INET An implementation of the TCP/IP protocol suite for the LINUX
* operating system. INET is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* IP/TCP/UDP checksumming routines
*
* Xtensa version: Copyright (C) 2001 Tensilica, Inc. by Kevin Chea
* Optimized by Joe Taylor
*/
#include <linux/errno.h>
#include <linux/linkage.h>
#include <asm/asmmacro.h>
#include <asm/core.h>
/*
* computes a partial checksum, e.g. for TCP/UDP fragments
*/
/*
* unsigned int csum_partial(const unsigned char *buf, int len,
* unsigned int sum);
* a2 = buf
* a3 = len
* a4 = sum
*
* This function assumes 2- or 4-byte alignment. Other alignments will fail!
*/
/* ONES_ADD converts twos-complement math to ones-complement. */
#define ONES_ADD(sum, val) \
add sum, sum, val ; \
bgeu sum, val, 99f ; \
addi sum, sum, 1 ; \
99: ;
.text
ENTRY(csum_partial)
/*
* Experiments with Ethernet and SLIP connections show that buf
* is aligned on either a 2-byte or 4-byte boundary.
*/
abi_entry_default
extui a5, a2, 0, 2
bnez a5, 8f /* branch if 2-byte aligned */
/* Fall-through on common case, 4-byte alignment */
1:
srli a5, a3, 5 /* 32-byte chunks */
#if XCHAL_HAVE_LOOPS
loopgtz a5, 2f
#else
beqz a5, 2f
slli a5, a5, 5
add a5, a5, a2 /* a5 = end of last 32-byte chunk */
.Loop1:
#endif
l32i a6, a2, 0
l32i a7, a2, 4
ONES_ADD(a4, a6)
ONES_ADD(a4, a7)
l32i a6, a2, 8
l32i a7, a2, 12
ONES_ADD(a4, a6)
ONES_ADD(a4, a7)
l32i a6, a2, 16
l32i a7, a2, 20
ONES_ADD(a4, a6)
ONES_ADD(a4, a7)
l32i a6, a2, 24
l32i a7, a2, 28
ONES_ADD(a4, a6)
ONES_ADD(a4, a7)
addi a2, a2, 4*8
#if !XCHAL_HAVE_LOOPS
blt a2, a5, .Loop1
#endif
2:
extui a5, a3, 2, 3 /* remaining 4-byte chunks */
#if XCHAL_HAVE_LOOPS
loopgtz a5, 3f
#else
beqz a5, 3f
slli a5, a5, 2
add a5, a5, a2 /* a5 = end of last 4-byte chunk */
.Loop2:
#endif
l32i a6, a2, 0
ONES_ADD(a4, a6)
addi a2, a2, 4
#if !XCHAL_HAVE_LOOPS
blt a2, a5, .Loop2
#endif
3:
_bbci.l a3, 1, 5f /* remaining 2-byte chunk */
l16ui a6, a2, 0
ONES_ADD(a4, a6)
addi a2, a2, 2
5:
_bbci.l a3, 0, 7f /* remaining 1-byte chunk */
6: l8ui a6, a2, 0
#ifdef __XTENSA_EB__
slli a6, a6, 8 /* load byte into bits 8..15 */
#endif
ONES_ADD(a4, a6)
7:
mov a2, a4
abi_ret_default
/* uncommon case, buf is 2-byte aligned */
8:
beqz a3, 7b /* branch if len == 0 */
beqi a3, 1, 6b /* branch if len == 1 */
extui a5, a2, 0, 1
bnez a5, 8f /* branch if 1-byte aligned */
l16ui a6, a2, 0 /* common case, len >= 2 */
ONES_ADD(a4, a6)
addi a2, a2, 2 /* adjust buf */
addi a3, a3, -2 /* adjust len */
j 1b /* now buf is 4-byte aligned */
/* case: odd-byte aligned, len > 1
* This case is dog slow, so don't give us an odd address.
* (I don't think this ever happens, but just in case.)
*/
8:
srli a5, a3, 2 /* 4-byte chunks */
#if XCHAL_HAVE_LOOPS
loopgtz a5, 2f
#else
beqz a5, 2f
slli a5, a5, 2
add a5, a5, a2 /* a5 = end of last 4-byte chunk */
.Loop3:
#endif
l8ui a6, a2, 0 /* bits 24..31 */
l16ui a7, a2, 1 /* bits 8..23 */
l8ui a8, a2, 3 /* bits 0.. 8 */
#ifdef __XTENSA_EB__
slli a6, a6, 24
#else
slli a8, a8, 24
#endif
slli a7, a7, 8
or a7, a7, a6
or a7, a7, a8
ONES_ADD(a4, a7)
addi a2, a2, 4
#if !XCHAL_HAVE_LOOPS
blt a2, a5, .Loop3
#endif
2:
_bbci.l a3, 1, 3f /* remaining 2-byte chunk, still odd addr */
l8ui a6, a2, 0
l8ui a7, a2, 1
#ifdef __XTENSA_EB__
slli a6, a6, 8
#else
slli a7, a7, 8
#endif
or a7, a7, a6
ONES_ADD(a4, a7)
addi a2, a2, 2
3:
j 5b /* branch to handle the remaining byte */
ENDPROC(csum_partial)
/*
* Copy from ds while checksumming, otherwise like csum_partial
*/
/*
unsigned int csum_partial_copy_generic (const char *src, char *dst, int len,
int sum, int *src_err_ptr, int *dst_err_ptr)
a2 = src
a3 = dst
a4 = len
a5 = sum
a6 = src_err_ptr
a7 = dst_err_ptr
a8 = temp
a9 = temp
a10 = temp
a11 = original len for exception handling
a12 = original dst for exception handling
This function is optimized for 4-byte aligned addresses. Other
alignments work, but not nearly as efficiently.
*/
ENTRY(csum_partial_copy_generic)
abi_entry_default
mov a12, a3
mov a11, a4
or a10, a2, a3
/* We optimize the following alignment tests for the 4-byte
aligned case. Two bbsi.l instructions might seem more optimal
(commented out below). However, both labels 5: and 3: are out
of the imm8 range, so the assembler relaxes them into
equivalent bbci.l, j combinations, which is actually
slower. */
extui a9, a10, 0, 2
beqz a9, 1f /* branch if both are 4-byte aligned */
bbsi.l a10, 0, 5f /* branch if one address is odd */
j 3f /* one address is 2-byte aligned */
/* _bbsi.l a10, 0, 5f */ /* branch if odd address */
/* _bbsi.l a10, 1, 3f */ /* branch if 2-byte-aligned address */
1:
/* src and dst are both 4-byte aligned */
srli a10, a4, 5 /* 32-byte chunks */
#if XCHAL_HAVE_LOOPS
loopgtz a10, 2f
#else
beqz a10, 2f
slli a10, a10, 5
add a10, a10, a2 /* a10 = end of last 32-byte src chunk */
.Loop5:
#endif
EX(10f) l32i a9, a2, 0
EX(10f) l32i a8, a2, 4
EX(11f) s32i a9, a3, 0
EX(11f) s32i a8, a3, 4
ONES_ADD(a5, a9)
ONES_ADD(a5, a8)
EX(10f) l32i a9, a2, 8
EX(10f) l32i a8, a2, 12
EX(11f) s32i a9, a3, 8
EX(11f) s32i a8, a3, 12
ONES_ADD(a5, a9)
ONES_ADD(a5, a8)
EX(10f) l32i a9, a2, 16
EX(10f) l32i a8, a2, 20
EX(11f) s32i a9, a3, 16
EX(11f) s32i a8, a3, 20
ONES_ADD(a5, a9)
ONES_ADD(a5, a8)
EX(10f) l32i a9, a2, 24
EX(10f) l32i a8, a2, 28
EX(11f) s32i a9, a3, 24
EX(11f) s32i a8, a3, 28
ONES_ADD(a5, a9)
ONES_ADD(a5, a8)
addi a2, a2, 32
addi a3, a3, 32
#if !XCHAL_HAVE_LOOPS
blt a2, a10, .Loop5
#endif
2:
extui a10, a4, 2, 3 /* remaining 4-byte chunks */
extui a4, a4, 0, 2 /* reset len for general-case, 2-byte chunks */
#if XCHAL_HAVE_LOOPS
loopgtz a10, 3f
#else
beqz a10, 3f
slli a10, a10, 2
add a10, a10, a2 /* a10 = end of last 4-byte src chunk */
.Loop6:
#endif
EX(10f) l32i a9, a2, 0
EX(11f) s32i a9, a3, 0
ONES_ADD(a5, a9)
addi a2, a2, 4
addi a3, a3, 4
#if !XCHAL_HAVE_LOOPS
blt a2, a10, .Loop6
#endif
3:
/*
Control comes to here in two cases: (1) It may fall through
to here from the 4-byte alignment case to process, at most,
one 2-byte chunk. (2) It branches to here from above if
either src or dst is 2-byte aligned, and we process all bytes
here, except for perhaps a trailing odd byte. It's
inefficient, so align your addresses to 4-byte boundaries.
a2 = src
a3 = dst
a4 = len
a5 = sum
*/
srli a10, a4, 1 /* 2-byte chunks */
#if XCHAL_HAVE_LOOPS
loopgtz a10, 4f
#else
beqz a10, 4f
slli a10, a10, 1
add a10, a10, a2 /* a10 = end of last 2-byte src chunk */
.Loop7:
#endif
EX(10f) l16ui a9, a2, 0
EX(11f) s16i a9, a3, 0
ONES_ADD(a5, a9)
addi a2, a2, 2
addi a3, a3, 2
#if !XCHAL_HAVE_LOOPS
blt a2, a10, .Loop7
#endif
4:
/* This section processes a possible trailing odd byte. */
_bbci.l a4, 0, 8f /* 1-byte chunk */
EX(10f) l8ui a9, a2, 0
EX(11f) s8i a9, a3, 0
#ifdef __XTENSA_EB__
slli a9, a9, 8 /* shift byte to bits 8..15 */
#endif
ONES_ADD(a5, a9)
8:
mov a2, a5
abi_ret_default
5:
/* Control branch to here when either src or dst is odd. We
process all bytes using 8-bit accesses. Grossly inefficient,
so don't feed us an odd address. */
srli a10, a4, 1 /* handle in pairs for 16-bit csum */
#if XCHAL_HAVE_LOOPS
loopgtz a10, 6f
#else
beqz a10, 6f
slli a10, a10, 1
add a10, a10, a2 /* a10 = end of last odd-aligned, 2-byte src chunk */
.Loop8:
#endif
EX(10f) l8ui a9, a2, 0
EX(10f) l8ui a8, a2, 1
EX(11f) s8i a9, a3, 0
EX(11f) s8i a8, a3, 1
#ifdef __XTENSA_EB__
slli a9, a9, 8 /* combine into a single 16-bit value */
#else /* for checksum computation */
slli a8, a8, 8
#endif
or a9, a9, a8
ONES_ADD(a5, a9)
addi a2, a2, 2
addi a3, a3, 2
#if !XCHAL_HAVE_LOOPS
blt a2, a10, .Loop8
#endif
6:
j 4b /* process the possible trailing odd byte */
ENDPROC(csum_partial_copy_generic)
# Exception handler:
.section .fixup, "ax"
/*
a6 = src_err_ptr
a7 = dst_err_ptr
a11 = original len for exception handling
a12 = original dst for exception handling
*/
10:
_movi a2, -EFAULT
s32i a2, a6, 0 /* src_err_ptr */
# clear the complete destination - computing the rest
# is too much work
movi a2, 0
#if XCHAL_HAVE_LOOPS
loopgtz a11, 2f
#else
beqz a11, 2f
add a11, a11, a12 /* a11 = ending address */
.Leloop:
#endif
s8i a2, a12, 0
addi a12, a12, 1
#if !XCHAL_HAVE_LOOPS
blt a12, a11, .Leloop
#endif
2:
abi_ret_default
11:
movi a2, -EFAULT
s32i a2, a7, 0 /* dst_err_ptr */
movi a2, 0
abi_ret_default
.previous
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