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