diff options
Diffstat (limited to 'arch/powerpc/lib/checksum_64.S')
| -rw-r--r-- | arch/powerpc/lib/checksum_64.S | 289 |
1 files changed, 202 insertions, 87 deletions
diff --git a/arch/powerpc/lib/checksum_64.S b/arch/powerpc/lib/checksum_64.S index 404d5a6e3387..18245af38aea 100644 --- a/arch/powerpc/lib/checksum_64.S +++ b/arch/powerpc/lib/checksum_64.S @@ -228,115 +228,230 @@ _GLOBAL(csum_partial) srdi r3,r3,32 blr + + .macro source +100: + .section __ex_table,"a" + .align 3 + .llong 100b,.Lsrc_error + .previous + .endm + + .macro dest +200: + .section __ex_table,"a" + .align 3 + .llong 200b,.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, and (for an error on - * src) zeroes the rest of dst. - * - * This code needs to be reworked to take advantage of 64 bit sum+copy. - * However, due to tokenring halfword alignment problems this will be very - * tricky. For now we'll leave it until we instrument it somehow. + * 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 - subi r3,r3,4 - subi r4,r4,4 - srwi. r6,r5,2 - beq 3f /* if we're doing < 4 bytes */ - andi. r9,r4,2 /* Align dst to longword boundary */ - beq+ 1f -81: lhz r6,4(r3) /* do 2 bytes to get aligned */ - addi r3,r3,2 + 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 r7,4 + sub r6,r7,r6 + mtctr r6 + +1: +source; lhz r6,0(r3) /* align to doubleword */ subi r5,r5,2 -91: sth r6,4(r4) - addi r4,r4,2 - addc r0,r0,r6 - srwi. r6,r5,2 /* # words to do */ - beq 3f -1: mtctr r6 -82: lwzu r6,4(r3) /* the bdnz has zero overhead, so it should */ -92: stwu r6,4(r4) /* be unnecessary to unroll this loop */ - adde r0,r0,r6 - bdnz 82b - andi. r5,r5,3 -3: cmpwi 0,r5,2 - blt+ 4f -83: lhz r6,4(r3) addi r3,r3,2 - subi r5,r5,2 -93: sth r6,4(r4) + adde r0,r0,r6 +dest; 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 -4: cmpwi 0,r5,1 - bne+ 5f -84: lbz r6,4(r3) -94: stb r6,4(r4) - slwi r6,r6,8 /* Upper byte of word */ +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: +source; ld r6,0(r3) + addi r3,r3,8 adde r0,r0,r6 -5: addze r3,r0 /* add in final carry (unlikely with 64-bit regs) */ - rldicl r4,r3,32,0 /* fold 64 bit value */ - add r3,r4,r3 - srdi r3,r3,32 - blr +dest; std r6,0(r4) + addi r4,r4,8 + bdnz 3b -/* These shouldn't go in the fixup section, since that would - cause the ex_table addresses to get out of order. */ + andi. r5,r5,7 - .globl src_error_1 -src_error_1: - li r6,0 - subi r5,r5,2 -95: sth r6,4(r4) +.Lcopy_tail_word: /* Up to 7 bytes to go */ + srdi. r6,r5,2 + beq .Lcopy_tail_halfword + +source; lwz r6,0(r3) + addi r3,r3,4 + adde r0,r0,r6 +dest; 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 + +source; lhz r6,0(r3) + addi r3,r3,2 + adde r0,r0,r6 +dest; sth r6,0(r4) addi r4,r4,2 - srwi. r6,r5,2 - beq 3f - mtctr r6 - .globl src_error_2 -src_error_2: - li r6,0 -96: stwu r6,4(r4) - bdnz 96b -3: andi. r5,r5,3 - beq src_error - .globl src_error_3 -src_error_3: - li r6,0 - mtctr r5 - addi r4,r4,3 -97: stbu r6,1(r4) - bdnz 97b - .globl src_error -src_error: + subi r5,r5,2 + +.Lcopy_tail_byte: /* Up to 1 byte to go */ + andi. r6,r5,1 + beq .Lcopy_finish + +source; lbz r6,0(r3) + sldi r9,r6,8 /* Pad the byte out to 16 bits */ + adde r0,r0,r9 +dest; 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: cmpdi 0,r7,0 - beq 1f + beqlr li r6,-EFAULT stw r6,0(r7) -1: addze r3,r0 blr - .globl dst_error -dst_error: +.Ldest_error: cmpdi 0,r8,0 - beq 1f + beqlr li r6,-EFAULT stw r6,0(r8) -1: addze r3,r0 blr - -.section __ex_table,"a" - .align 3 - .llong 81b,src_error_1 - .llong 91b,dst_error - .llong 82b,src_error_2 - .llong 92b,dst_error - .llong 83b,src_error_3 - .llong 93b,dst_error - .llong 84b,src_error_3 - .llong 94b,dst_error - .llong 95b,dst_error - .llong 96b,dst_error - .llong 97b,dst_error |