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| /* SPDX-License-Identifier: GPL-2.0 */
| /*
| * Optmized version of the ip_fast_csum() function
| * Used for calculating IP header checksum
| *
| * Return: 16bit checksum, complemented
| *
| * Inputs:
| * in0: address of buffer to checksum (char *)
| * in1: length of the buffer (int)
| *
| * Copyright (C) 2002, 2006 Intel Corp.
| * Copyright (C) 2002, 2006 Ken Chen <kenneth.w.chen@intel.com>
| */
|
| #include <asm/asmmacro.h>
| #include <asm/export.h>
|
| /*
| * Since we know that most likely this function is called with buf aligned
| * on 4-byte boundary and 20 bytes in length, we can execution rather quickly
| * versus calling generic version of do_csum, which has lots of overhead in
| * handling various alignments and sizes. However, due to lack of constrains
| * put on the function input argument, cases with alignment not on 4-byte or
| * size not equal to 20 bytes will be handled by the generic do_csum function.
| */
|
| #define in0 r32
| #define in1 r33
| #define in2 r34
| #define in3 r35
| #define in4 r36
| #define ret0 r8
|
| GLOBAL_ENTRY(ip_fast_csum)
| .prologue
| .body
| cmp.ne p6,p7=5,in1 // size other than 20 byte?
| and r14=3,in0 // is it aligned on 4-byte?
| add r15=4,in0 // second source pointer
| ;;
| cmp.ne.or.andcm p6,p7=r14,r0
| ;;
| (p7) ld4 r20=[in0],8
| (p7) ld4 r21=[r15],8
| (p6) br.spnt .generic
| ;;
| ld4 r22=[in0],8
| ld4 r23=[r15],8
| ;;
| ld4 r24=[in0]
| add r20=r20,r21
| add r22=r22,r23
| ;;
| add r20=r20,r22
| ;;
| add r20=r20,r24
| ;;
| shr.u ret0=r20,16 // now need to add the carry
| zxt2 r20=r20
| ;;
| add r20=ret0,r20
| ;;
| shr.u ret0=r20,16 // add carry again
| zxt2 r20=r20
| ;;
| add r20=ret0,r20
| ;;
| shr.u ret0=r20,16
| zxt2 r20=r20
| ;;
| add r20=ret0,r20
| mov r9=0xffff
| ;;
| andcm ret0=r9,r20
| .restore sp // reset frame state
| br.ret.sptk.many b0
| ;;
|
| .generic:
| .prologue
| .save ar.pfs, r35
| alloc r35=ar.pfs,2,2,2,0
| .save rp, r34
| mov r34=b0
| .body
| dep.z out1=in1,2,30
| mov out0=in0
| ;;
| br.call.sptk.many b0=do_csum
| ;;
| andcm ret0=-1,ret0
| mov ar.pfs=r35
| mov b0=r34
| br.ret.sptk.many b0
| END(ip_fast_csum)
| EXPORT_SYMBOL(ip_fast_csum)
|
| GLOBAL_ENTRY(csum_ipv6_magic)
| ld4 r20=[in0],4
| ld4 r21=[in1],4
| zxt4 in2=in2
| ;;
| ld4 r22=[in0],4
| ld4 r23=[in1],4
| dep r15=in3,in2,32,16
| ;;
| ld4 r24=[in0],4
| ld4 r25=[in1],4
| mux1 r15=r15,@rev
| add r16=r20,r21
| add r17=r22,r23
| zxt4 in4=in4
| ;;
| ld4 r26=[in0],4
| ld4 r27=[in1],4
| shr.u r15=r15,16
| add r18=r24,r25
| add r8=r16,r17
| ;;
| add r19=r26,r27
| add r8=r8,r18
| ;;
| add r8=r8,r19
| add r15=r15,in4
| ;;
| add r8=r8,r15
| ;;
| shr.u r10=r8,32 // now fold sum into short
| zxt4 r11=r8
| ;;
| add r8=r10,r11
| ;;
| shr.u r10=r8,16 // yeah, keep it rolling
| zxt2 r11=r8
| ;;
| add r8=r10,r11
| ;;
| shr.u r10=r8,16 // three times lucky
| zxt2 r11=r8
| ;;
| add r8=r10,r11
| mov r9=0xffff
| ;;
| andcm r8=r9,r8
| br.ret.sptk.many b0
| END(csum_ipv6_magic)
| EXPORT_SYMBOL(csum_ipv6_magic)
|
|
