Commit d9813c36 authored Oct 01, 2013 by Paul E. McKenney Committed by Benjamin Herrenschmidt Oct 03, 2013

powerpc: Fix parameter clobber in csum_partial_copy_generic()



The csum_partial_copy_generic() uses register r7 to adjust the remaining
bytes to process.  Unfortunately, r7 also holds a parameter, namely the
address of the flag to set in case of access exceptions while reading
the source buffer.  Lacking a quantum implementation of PowerPC, this
commit instead uses register r9 to do the adjusting, leaving r7's
pointer uncorrupted.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: stable@vger.kernel.org
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

parent f7e3334a

arch/powerpc/lib/checksum_64.S

+2 −2

Original line number	Diff line number	Diff line
		@@ -269,8 +269,8 @@ _GLOBAL(csum_partial_copy_generic)
		rldicl. r6,r3,64-1,64-2 /* r6 = (r3 & 0x3) >> 1 */
		beq .Lcopy_aligned

		li r7,4
		sub r6,r7,r6
		li r9,4
		sub r6,r9,r6
		mtctr r6

		1: