--- /dev/null
+/*
+ * This file contains assembly-language implementations
+ * of IP-style 1's complement checksum routines.
+ *
+ * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ * Severely hacked about by Paul Mackerras (paulus@cs.anu.edu.au).
+ */
+
+#include <linux/sys.h>
+#include <asm/processor.h>
+#include <asm/errno.h>
+#include <asm/ppc_asm.h>
+
+/*
+ * ip_fast_csum(r3=buf, r4=len) -- Optimized for IP header
+ * len is in words and is always >= 5.
+ *
+ * In practice len == 5, but this is not guaranteed. So this code does not
+ * attempt to use doubleword instructions.
+ */
+_GLOBAL(ip_fast_csum)
+ lwz r0,0(r3)
+ lwzu r5,4(r3)
+ addic. r4,r4,-2
+ addc r0,r0,r5
+ mtctr r4
+ blelr-
+1: lwzu r4,4(r3)
+ adde r0,r0,r4
+ bdnz 1b
+ addze r0,r0 /* add in final carry */
+ rldicl r4,r0,32,0 /* fold two 32-bit halves together */
+ add r0,r0,r4
+ srdi r0,r0,32
+ rlwinm r3,r0,16,0,31 /* fold two halves together */
+ add r3,r0,r3
+ not r3,r3
+ srwi r3,r3,16
+ blr
+
+/*
+ * Compute checksum of TCP or UDP pseudo-header:
+ * csum_tcpudp_magic(r3=saddr, r4=daddr, r5=len, r6=proto, r7=sum)
+ * No real gain trying to do this specially for 64 bit, but
+ * the 32 bit addition may spill into the upper bits of
+ * the doubleword so we still must fold it down from 64.
+ */
+_GLOBAL(csum_tcpudp_magic)
+ rlwimi r5,r6,16,0,15 /* put proto in upper half of len */
+ addc r0,r3,r4 /* add 4 32-bit words together */
+ adde r0,r0,r5
+ adde r0,r0,r7
+ rldicl r4,r0,32,0 /* fold 64 bit value */
+ add r0,r4,r0
+ srdi r0,r0,32
+ rlwinm r3,r0,16,0,31 /* fold two halves together */
+ add r3,r0,r3
+ not r3,r3
+ srwi r3,r3,16
+ blr
+
+/*
+ * Computes the checksum of a memory block at buff, length len,
+ * and adds in "sum" (32-bit).
+ *
+ * csum_partial(r3=buff, r4=len, r5=sum)
+ */
+_GLOBAL(csum_partial)
+ addic r0,r5,0 /* clear carry */
+
+ srdi. r6,r4,3 /* less than 8 bytes? */
+ beq .Lcsum_tail_word
+
+ /*
+ * If only halfword aligned, align to a double word. Since odd
+ * aligned addresses should be rare and they would require more
+ * work to calculate the correct checksum, we ignore that case
+ * and take the potential slowdown of unaligned loads.
+ */
+ rldicl. r6,r3,64-1,64-2 /* r6 = (r3 & 0x3) >> 1 */
+ beq .Lcsum_aligned
+
+ li r7,4
+ sub r6,r7,r6
+ mtctr r6
+
+1:
+ lhz r6,0(r3) /* align to doubleword */
+ subi r4,r4,2
+ addi r3,r3,2
+ adde r0,r0,r6
+ bdnz 1b
+
+.Lcsum_aligned:
+ /*
+ * We unroll the loop such that each iteration is 64 bytes with an
+ * entry and exit limb of 64 bytes, meaning a minimum size of
+ * 128 bytes.
+ */
+ srdi. r6,r4,7
+ beq .Lcsum_tail_doublewords /* len < 128 */
+
+ srdi r6,r4,6
+ subi r6,r6,1
+ mtctr r6
+
+ stdu r1,-STACKFRAMESIZE(r1)
+ std r14,STK_REG(R14)(r1)
+ std r15,STK_REG(R15)(r1)
+ std r16,STK_REG(R16)(r1)
+
+ ld r6,0(r3)
+ ld r9,8(r3)
+
+ ld r10,16(r3)
+ ld r11,24(r3)
+
+ /*
+ * On POWER6 and POWER7 back to back addes take 2 cycles because of
+ * the XER dependency. This means the fastest this loop can go is
+ * 16 cycles per iteration. The scheduling of the loop below has
+ * been shown to hit this on both POWER6 and POWER7.
+ */
+ .align 5
+2:
+ adde r0,r0,r6
+ ld r12,32(r3)
+ ld r14,40(r3)
+
+ adde r0,r0,r9
+ ld r15,48(r3)
+ ld r16,56(r3)
+ addi r3,r3,64
+
+ adde r0,r0,r10
+
+ adde r0,r0,r11
+
+ adde r0,r0,r12
+
+ adde r0,r0,r14
+
+ adde r0,r0,r15
+ ld r6,0(r3)
+ ld r9,8(r3)
+
+ adde r0,r0,r16
+ ld r10,16(r3)
+ ld r11,24(r3)
+ bdnz 2b
+
+
+ adde r0,r0,r6
+ ld r12,32(r3)
+ ld r14,40(r3)
+
+ adde r0,r0,r9
+ ld r15,48(r3)
+ ld r16,56(r3)
+ addi r3,r3,64
+
+ adde r0,r0,r10
+ adde r0,r0,r11
+ adde r0,r0,r12
+ adde r0,r0,r14
+ adde r0,r0,r15
+ adde r0,r0,r16
+
+ ld r14,STK_REG(R14)(r1)
+ ld r15,STK_REG(R15)(r1)
+ ld r16,STK_REG(R16)(r1)
+ addi r1,r1,STACKFRAMESIZE
+
+ andi. r4,r4,63
+
+.Lcsum_tail_doublewords: /* Up to 127 bytes to go */
+ srdi. r6,r4,3
+ beq .Lcsum_tail_word
+
+ mtctr r6
+3:
+ ld r6,0(r3)
+ addi r3,r3,8
+ adde r0,r0,r6
+ bdnz 3b
+
+ andi. r4,r4,7
+
+.Lcsum_tail_word: /* Up to 7 bytes to go */
+ srdi. r6,r4,2
+ beq .Lcsum_tail_halfword
+
+ lwz r6,0(r3)
+ addi r3,r3,4
+ adde r0,r0,r6
+ subi r4,r4,4
+
+.Lcsum_tail_halfword: /* Up to 3 bytes to go */
+ srdi. r6,r4,1
+ beq .Lcsum_tail_byte
+
+ lhz r6,0(r3)
+ addi r3,r3,2
+ adde r0,r0,r6
+ subi r4,r4,2
+
+.Lcsum_tail_byte: /* Up to 1 byte to go */
+ andi. r6,r4,1
+ beq .Lcsum_finish
+
+ lbz r6,0(r3)
+ sldi r9,r6,8 /* Pad the byte out to 16 bits */
+ adde r0,r0,r9
+
+.Lcsum_finish:
+ addze r0,r0 /* add in final carry */
+ rldicl r4,r0,32,0 /* fold two 32 bit halves together */
+ add r3,r4,r0
+ srdi r3,r3,32
+ blr
+
+
+ .macro srcnr
+100:
+ .section __ex_table,"a"
+ .align 3
+ .llong 100b,.Lsrc_error_nr
+ .previous
+ .endm
+
+ .macro source
+150:
+ .section __ex_table,"a"
+ .align 3
+ .llong 150b,.Lsrc_error
+ .previous
+ .endm
+
+ .macro dstnr
+200:
+ .section __ex_table,"a"
+ .align 3
+ .llong 200b,.Ldest_error_nr
+ .previous
+ .endm
+
+ .macro dest
+250:
+ .section __ex_table,"a"
+ .align 3
+ .llong 250b,.Ldest_error
+ .previous
+ .endm
+
+/*
+ * Computes the checksum of a memory block at src, length len,
+ * and adds in "sum" (32-bit), while copying the block to dst.
+ * If an access exception occurs on src or dst, it stores -EFAULT
+ * to *src_err or *dst_err respectively. The caller must take any action
+ * required in this case (zeroing memory, recalculating partial checksum etc).
+ *
+ * csum_partial_copy_generic(r3=src, r4=dst, r5=len, r6=sum, r7=src_err, r8=dst_err)
+ */
+_GLOBAL(csum_partial_copy_generic)
+ addic r0,r6,0 /* clear carry */
+
+ srdi. r6,r5,3 /* less than 8 bytes? */
+ beq .Lcopy_tail_word
+
+ /*
+ * If only halfword aligned, align to a double word. Since odd
+ * aligned addresses should be rare and they would require more
+ * work to calculate the correct checksum, we ignore that case
+ * and take the potential slowdown of unaligned loads.
+ *
+ * If the source and destination are relatively unaligned we only
+ * align the source. This keeps things simple.
+ */
+ rldicl. r6,r3,64-1,64-2 /* r6 = (r3 & 0x3) >> 1 */
+ beq .Lcopy_aligned
+
+ li r9,4
+ sub r6,r9,r6
+ mtctr r6
+
+1:
+srcnr; lhz r6,0(r3) /* align to doubleword */
+ subi r5,r5,2
+ addi r3,r3,2
+ adde r0,r0,r6
+dstnr; sth r6,0(r4)
+ addi r4,r4,2
+ bdnz 1b
+
+.Lcopy_aligned:
+ /*
+ * We unroll the loop such that each iteration is 64 bytes with an
+ * entry and exit limb of 64 bytes, meaning a minimum size of
+ * 128 bytes.
+ */
+ srdi. r6,r5,7
+ beq .Lcopy_tail_doublewords /* len < 128 */
+
+ srdi r6,r5,6
+ subi r6,r6,1
+ mtctr r6
+
+ stdu r1,-STACKFRAMESIZE(r1)
+ std r14,STK_REG(R14)(r1)
+ std r15,STK_REG(R15)(r1)
+ std r16,STK_REG(R16)(r1)
+
+source; ld r6,0(r3)
+source; ld r9,8(r3)
+
+source; ld r10,16(r3)
+source; ld r11,24(r3)
+
+ /*
+ * On POWER6 and POWER7 back to back addes take 2 cycles because of
+ * the XER dependency. This means the fastest this loop can go is
+ * 16 cycles per iteration. The scheduling of the loop below has
+ * been shown to hit this on both POWER6 and POWER7.
+ */
+ .align 5
+2:
+ adde r0,r0,r6
+source; ld r12,32(r3)
+source; ld r14,40(r3)
+
+ adde r0,r0,r9
+source; ld r15,48(r3)
+source; ld r16,56(r3)
+ addi r3,r3,64
+
+ adde r0,r0,r10
+dest; std r6,0(r4)
+dest; std r9,8(r4)
+
+ adde r0,r0,r11
+dest; std r10,16(r4)
+dest; std r11,24(r4)
+
+ adde r0,r0,r12
+dest; std r12,32(r4)
+dest; std r14,40(r4)
+
+ adde r0,r0,r14
+dest; std r15,48(r4)
+dest; std r16,56(r4)
+ addi r4,r4,64
+
+ adde r0,r0,r15
+source; ld r6,0(r3)
+source; ld r9,8(r3)
+
+ adde r0,r0,r16
+source; ld r10,16(r3)
+source; ld r11,24(r3)
+ bdnz 2b
+
+
+ adde r0,r0,r6
+source; ld r12,32(r3)
+source; ld r14,40(r3)
+
+ adde r0,r0,r9
+source; ld r15,48(r3)
+source; ld r16,56(r3)
+ addi r3,r3,64
+
+ adde r0,r0,r10
+dest; std r6,0(r4)
+dest; std r9,8(r4)
+
+ adde r0,r0,r11
+dest; std r10,16(r4)
+dest; std r11,24(r4)
+
+ adde r0,r0,r12
+dest; std r12,32(r4)
+dest; std r14,40(r4)
+
+ adde r0,r0,r14
+dest; std r15,48(r4)
+dest; std r16,56(r4)
+ addi r4,r4,64
+
+ adde r0,r0,r15
+ adde r0,r0,r16
+
+ ld r14,STK_REG(R14)(r1)
+ ld r15,STK_REG(R15)(r1)
+ ld r16,STK_REG(R16)(r1)
+ addi r1,r1,STACKFRAMESIZE
+
+ andi. r5,r5,63
+
+.Lcopy_tail_doublewords: /* Up to 127 bytes to go */
+ srdi. r6,r5,3
+ beq .Lcopy_tail_word
+
+ mtctr r6
+3:
+srcnr; ld r6,0(r3)
+ addi r3,r3,8
+ adde r0,r0,r6
+dstnr; std r6,0(r4)
+ addi r4,r4,8
+ bdnz 3b
+
+ andi. r5,r5,7
+
+.Lcopy_tail_word: /* Up to 7 bytes to go */
+ srdi. r6,r5,2
+ beq .Lcopy_tail_halfword
+
+srcnr; lwz r6,0(r3)
+ addi r3,r3,4
+ adde r0,r0,r6
+dstnr; stw r6,0(r4)
+ addi r4,r4,4
+ subi r5,r5,4
+
+.Lcopy_tail_halfword: /* Up to 3 bytes to go */
+ srdi. r6,r5,1
+ beq .Lcopy_tail_byte
+
+srcnr; lhz r6,0(r3)
+ addi r3,r3,2
+ adde r0,r0,r6
+dstnr; sth r6,0(r4)
+ addi r4,r4,2
+ subi r5,r5,2
+
+.Lcopy_tail_byte: /* Up to 1 byte to go */
+ andi. r6,r5,1
+ beq .Lcopy_finish
+
+srcnr; lbz r6,0(r3)
+ sldi r9,r6,8 /* Pad the byte out to 16 bits */
+ adde r0,r0,r9
+dstnr; stb r6,0(r4)
+
+.Lcopy_finish:
+ addze r0,r0 /* add in final carry */
+ rldicl r4,r0,32,0 /* fold two 32 bit halves together */
+ add r3,r4,r0
+ srdi r3,r3,32
+ blr
+
+.Lsrc_error:
+ ld r14,STK_REG(R14)(r1)
+ ld r15,STK_REG(R15)(r1)
+ ld r16,STK_REG(R16)(r1)
+ addi r1,r1,STACKFRAMESIZE
+.Lsrc_error_nr:
+ cmpdi 0,r7,0
+ beqlr
+ li r6,-EFAULT
+ stw r6,0(r7)
+ blr
+
+.Ldest_error:
+ ld r14,STK_REG(R14)(r1)
+ ld r15,STK_REG(R15)(r1)
+ ld r16,STK_REG(R16)(r1)
+ addi r1,r1,STACKFRAMESIZE
+.Ldest_error_nr:
+ cmpdi 0,r8,0
+ beqlr
+ li r6,-EFAULT
+ stw r6,0(r8)
+ blr
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