Patch "powerpc/32: Fix again csum_partial_copy_generic()" has been added to the 4.7-stable tree

Patch "powerpc/32: Fix again csum_partial_copy_generic()" has been added to the 4.7-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    powerpc/32: Fix again csum_partial_copy_generic()

to the 4.7-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     powerpc-32-fix-again-csum_partial_copy_generic.patch
and it can be found in the queue-4.7 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 8540571e01f973d321b0821f4f32ed6e9ae8263c Mon Sep 17 00:00:00 2001
From: Christophe Leroy <christophe.leroy@c-s.fr>
Date: Fri, 26 Aug 2016 16:45:13 +0200
Subject: powerpc/32: Fix again csum_partial_copy_generic()

From: Christophe Leroy <christophe.leroy@c-s.fr>

commit 8540571e01f973d321b0821f4f32ed6e9ae8263c upstream.

Commit 7aef4136566b0 ("powerpc32: rewrite csum_partial_copy_generic()
based on copy_tofrom_user()") introduced a bug when destination address
is odd and len is lower than cacheline size.

In that case the resulting csum value doesn't have to be rotated one
byte because the cache-aligned copy part is skipped so no alignment
is performed.

Fixes: 7aef4136566b0 ("powerpc32: rewrite csum_partial_copy_generic() based on copy_tofrom_user()")
Cc: stable@vger.kernel.org # v4.6+
Reported-by: Alessio Igor Bogani <alessio.bogani@elettra.eu>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Tested-by: Alessio Igor Bogani <alessio.bogani@elettra.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/powerpc/lib/checksum_32.S |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

--- a/arch/powerpc/lib/checksum_32.S
+++ b/arch/powerpc/lib/checksum_32.S
@@ -127,18 +127,19 @@ _GLOBAL(csum_partial_copy_generic)
 	stw	r7,12(r1)
 	stw	r8,8(r1)
 
-	rlwinm	r0,r4,3,0x8
-	rlwnm	r6,r6,r0,0,31	/* odd destination address: rotate one byte */
-	cmplwi	cr7,r0,0	/* is destination address even ? */
 	addic	r12,r6,0
 	addi	r6,r4,-4
 	neg	r0,r4
 	addi	r4,r3,-4
 	andi.	r0,r0,CACHELINE_MASK	/* # bytes to start of cache line */
+	crset	4*cr7+eq
 	beq	58f
 
 	cmplw	0,r5,r0			/* is this more than total to do? */
 	blt	63f			/* if not much to do */
+	rlwinm	r7,r6,3,0x8
+	rlwnm	r12,r12,r7,0,31	/* odd destination address: rotate one byte */
+	cmplwi	cr7,r7,0	/* is destination address even ? */
 	andi.	r8,r0,3			/* get it word-aligned first */
 	mtctr	r8
 	beq+	61f


Patches currently in stable-queue which might be from christophe.leroy@c-s.fr are

queue-4.7/powerpc-sysdev-cpm-fix-gpio-save_regs-functions.patch
queue-4.7/powerpc-32-fix-again-csum_partial_copy_generic.patch
queue-4.7/powerpc-32-fix-csum_partial_copy_generic.patch