[patch] alpha: strncpy/strncat fixes
From: Ivan Kokshaysky
Date: Tue Dec 11 2007 - 12:07:33 EST
First of all, thanks to Bob Tracy <rct@xxxxxxxx> and
Michael Cree <mcree@xxxxxxxxxxxx> for testing.
Especially to Bob, as he has done titanic multi-day git-bisect
work that finally helped to reproduce and nail down the bug
(http://bugzilla.kernel.org/show_bug.cgi?id=9457).
[ev6-]stxncpy.S: it's t12, not t2 register that is supposed to contain
the last byte offset upon return. As a result of wrong register use
(which was my fault back in 2003, IIRC), under some circumstances extra
terminating zero bytes were added to destination string. This particularly
led to incorrect DEVPATH strings generated in uevent and therefore to udev
problems.
strncpy.S: unrelated bug I found while testing the above fix - destination
is not properly zero-padded then a byte count exceeds source length.
Actually this is addition to strncpy fix from last year.
Signed-off-by: Ivan Kokshaysky <ink@xxxxxxxxxxxxxxxxxxxx>
Ivan.
--- 2.6.24-rc3/arch/alpha/lib/ev6-stxncpy.S Wed Oct 10 00:31:38 2007
+++ linux/arch/alpha/lib/ev6-stxncpy.S Tue Dec 11 02:28:57 2007
@@ -362,10 +362,10 @@ $unaligned:
extql t2, a1, t2 # U :
cmpbge zero, t1, t8 # E : is there a zero?
- andnot t2, t6, t12 # E : dest mask for a single word copy
+ andnot t2, t6, t2 # E : dest mask for a single word copy
or t8, t10, t5 # E : test for end-of-count too
- cmpbge zero, t12, t3 # E :
+ cmpbge zero, t2, t3 # E :
cmoveq a2, t5, t8 # E : Latency=2, extra map slot
nop # E : keep with cmoveq
andnot t8, t3, t8 # E : (stall)
@@ -379,13 +379,13 @@ $unaligned:
negq t8, t6 # E : build bitmask of bytes <= zero
mskqh t1, t4, t1 # U :
- and t6, t8, t2 # E :
- subq t2, 1, t6 # E : (stall)
- or t6, t2, t8 # E : (stall)
- zapnot t12, t8, t12 # U : prepare source word; mirror changes (stall)
+ and t6, t8, t12 # E :
+ subq t12, 1, t6 # E : (stall)
+ or t6, t12, t8 # E : (stall)
+ zapnot t2, t8, t2 # U : prepare source word; mirror changes (stall)
zapnot t1, t8, t1 # U : to source validity mask
- andnot t0, t12, t0 # E : zero place for source to reside
+ andnot t0, t2, t0 # E : zero place for source to reside
or t0, t1, t0 # E : and put it there (stall both t0, t1)
stq_u t0, 0(a0) # L : (stall)
--- 2.6.24-rc3/arch/alpha/lib/stxncpy.S Wed Oct 10 00:31:38 2007
+++ linux/arch/alpha/lib/stxncpy.S Tue Dec 11 02:28:57 2007
@@ -315,9 +315,9 @@ $unaligned:
extql t2, a1, t2 # e0 :
cmpbge zero, t1, t8 # .. e1 : is there a zero?
- andnot t2, t6, t12 # e0 : dest mask for a single word copy
+ andnot t2, t6, t2 # e0 : dest mask for a single word copy
or t8, t10, t5 # .. e1 : test for end-of-count too
- cmpbge zero, t12, t3 # e0 :
+ cmpbge zero, t2, t3 # e0 :
cmoveq a2, t5, t8 # .. e1 :
andnot t8, t3, t8 # e0 :
beq t8, $u_head # .. e1 (zdb)
@@ -330,14 +330,14 @@ $unaligned:
ldq_u t0, 0(a0) # e0 :
negq t8, t6 # .. e1 : build bitmask of bytes <= zero
mskqh t1, t4, t1 # e0 :
- and t6, t8, t2 # .. e1 :
- subq t2, 1, t6 # e0 :
- or t6, t2, t8 # e1 :
+ and t6, t8, t12 # .. e1 :
+ subq t12, 1, t6 # e0 :
+ or t6, t12, t8 # e1 :
- zapnot t12, t8, t12 # e0 : prepare source word; mirror changes
+ zapnot t2, t8, t2 # e0 : prepare source word; mirror changes
zapnot t1, t8, t1 # .. e1 : to source validity mask
- andnot t0, t12, t0 # e0 : zero place for source to reside
+ andnot t0, t2, t0 # e0 : zero place for source to reside
or t0, t1, t0 # e1 : and put it there
stq_u t0, 0(a0) # e0 :
ret (t9) # .. e1 :
--- 2.6.24-rc3/arch/alpha/lib/strncpy.S Wed Oct 10 00:31:38 2007
+++ linux/arch/alpha/lib/strncpy.S Tue Dec 11 02:28:57 2007
@@ -35,7 +35,7 @@ strncpy:
or $3, $24, $3 # clear the bits between the last
or $4, $27, $4 # written byte and the last byte in COUNT
- andnot $4, $3, $4
+ andnot $3, $4, $4
zap $1, $4, $1
stq_u $1, 0($16)
--
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