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| author | Ivan Kokshaysky <ink@jurassic.park.msu.ru> | 2007-06-24 02:16:35 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-06-24 17:59:11 +0200 |
| commit | 58ed2f9c75b719da4f494f24ed2d56d45f5b4959 (patch) | |
| tree | 6ecb60cf2d7b18da36fd29f2a6bd03d15a8cfefb /arch/alpha/lib/ev6-csum_ipv6_magic.S | |
| parent | update checkpatch.pl to version 0.05 (diff) | |
| download | linux-58ed2f9c75b719da4f494f24ed2d56d45f5b4959.tar.xz linux-58ed2f9c75b719da4f494f24ed2d56d45f5b4959.zip | |
alpha: fix alignment problem in csum_ipv6_magic()
Hopefully this fixes http://bugzilla.kernel.org/show_bug.cgi?id=8635
The struct in6_addr passed to csum_ipv6_magic() is 4 byte aligned, so we
can't use the regular 64-bit loads. Since the cost of handling of 4 byte
and 1 byte aligned 64-bit data is roughly the same, this code can cope with
any src/dst [mis]alignment.
Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Dustin Marquess <jailbird@alcatraz.fdf.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/alpha/lib/ev6-csum_ipv6_magic.S')
| -rw-r--r-- | arch/alpha/lib/ev6-csum_ipv6_magic.S | 42 |
1 files changed, 33 insertions, 9 deletions
diff --git a/arch/alpha/lib/ev6-csum_ipv6_magic.S b/arch/alpha/lib/ev6-csum_ipv6_magic.S index de1948a69118..fc0bc399f872 100644 --- a/arch/alpha/lib/ev6-csum_ipv6_magic.S +++ b/arch/alpha/lib/ev6-csum_ipv6_magic.S @@ -46,6 +46,10 @@ * add the 3 low ushorts together, generating a uint * a final add of the 2 lower ushorts * truncating the result. + * + * Misalignment handling added by Ivan Kokshaysky <ink@jurassic.park.msu.ru> + * The cost is 16 instructions (~8 cycles), including two extra loads which + * may cause additional delay in rare cases (load-load replay traps). */ .globl csum_ipv6_magic @@ -55,25 +59,45 @@ csum_ipv6_magic: .prologue 0 - ldq $0,0($16) # L : Latency: 3 + ldq_u $0,0($16) # L : Latency: 3 inslh $18,7,$4 # U : 0000000000AABBCC - ldq $1,8($16) # L : Latency: 3 + ldq_u $1,8($16) # L : Latency: 3 sll $19,8,$7 # U : U L U L : 0x00000000 00aabb00 + and $16,7,$6 # E : src misalignment + ldq_u $5,15($16) # L : Latency: 3 zapnot $20,15,$20 # U : zero extend incoming csum - ldq $2,0($17) # L : Latency: 3 - sll $19,24,$19 # U : U L L U : 0x000000aa bb000000 + ldq_u $2,0($17) # L : U L U L : Latency: 3 + + extql $0,$6,$0 # U : + extqh $1,$6,$22 # U : + ldq_u $3,8($17) # L : Latency: 3 + sll $19,24,$19 # U : U U L U : 0x000000aa bb000000 + + cmoveq $6,$31,$22 # E : src aligned? + ldq_u $23,15($17) # L : Latency: 3 inswl $18,3,$18 # U : 000000CCDD000000 + addl $19,$7,$19 # E : U L U L : <sign bits>bbaabb00 - ldq $3,8($17) # L : Latency: 3 - bis $18,$4,$18 # E : 000000CCDDAABBCC - addl $19,$7,$19 # E : <sign bits>bbaabb00 - nop # E : U L U L + or $0,$22,$0 # E : 1st src word complete + extql $1,$6,$1 # U : + or $18,$4,$18 # E : 000000CCDDAABBCC + extqh $5,$6,$5 # U : L U L U + and $17,7,$6 # E : dst misalignment + extql $2,$6,$2 # U : + or $1,$5,$1 # E : 2nd src word complete + extqh $3,$6,$22 # U : L U L U : + + cmoveq $6,$31,$22 # E : dst aligned? + extql $3,$6,$3 # U : addq $20,$0,$20 # E : begin summing the words + extqh $23,$6,$23 # U : L U L U : + srl $18,16,$4 # U : 0000000000CCDDAA + or $2,$22,$2 # E : 1st dst word complete zap $19,0x3,$19 # U : <sign bits>bbaa0000 - nop # E : L U U L + or $3,$23,$3 # E : U L U L : 2nd dst word complete cmpult $20,$0,$0 # E : addq $20,$1,$20 # E : |