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Commit b1054282 authored by Tkhai Kirill's avatar Tkhai Kirill Committed by David S. Miller
Browse files

sparc32: Fixed unaligned memory copying in function __csum_partial_copy_sparc_generic 



When we are in the label cc_dword_align, registers %o0 and %o1 have the same last 2 bits,
but it's not guaranteed one of them is zero. So we can get unaligned memory access
in label ccte. Example of parameters which lead to this:
%o0=0x7ff183e9, %o1=0x8e709e7d, %g1=3

With the parameters I had a memory corruption, when the additional 5 bytes were rewritten.
This patch corrects the error.

One comment to the patch. We don't care about the third bit in %o1, because cc_end_cruft
stores word or less.

Signed-off-by: default avatarTkhai Kirill <tkhai@yandex.ru>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f486b3dc

arch/sparc/lib/checksum_32.S

+9 −3
Original line number Diff line number Diff line
@@ -289,10 +289,16 @@ cc_end_cruft: 


	/* Also, handle the alignment code out of band. */

cc_dword_align:

	cmp	%g1, 6

	bl,a	ccte

	cmp	%g1, 16

	bge	1f

	 srl	%g1, 1, %o3

2:	cmp	%o3, 0

	be,a	ccte

	 andcc	%g1, 0xf, %o3

	andcc	%o0, 0x1, %g0

	andcc	%o3, %o0, %g0	! Check %o0 only (%o1 has the same last 2 bits)

	be,a	2b

	 srl	%o3, 1, %o3

1:	andcc	%o0, 0x1, %g0

	bne	ccslow

	 andcc	%o0, 0x2, %g0

	be	1f