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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)
| a2 = src
| a3 = dst
| a4 = len
| a5 = sum
| a8 = temp
| a9 = temp
| a10 = temp
|
| 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
| movi a5, -1
| 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(10f) s32i a9, a3, 0
| EX(10f) 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(10f) s32i a9, a3, 8
| EX(10f) 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(10f) s32i a9, a3, 16
| EX(10f) 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(10f) s32i a9, a3, 24
| EX(10f) 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(10f) 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(10f) 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(10f) 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(10f) s8i a9, a3, 0
| EX(10f) 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"
| 10:
| movi a2, 0
| abi_ret_default
|
| .previous
|
|
