This is a note to let you know that I've just added the patch titled
powerpc: Restore registers on error exit from csum_partial_copy_generic()
to the 3.0-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-restore-registers-on-error-exit-from-csum_partial_copy_generic.patch
and it can be found in the queue-3.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 8f21bd0090052e740944f9397e2be5ac7957ded7 Mon Sep 17 00:00:00 2001
From: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>
Date: Tue, 1 Oct 2013 17:11:35 +1000
Subject: powerpc: Restore registers on error exit from csum_partial_copy_generic()
From: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>
commit 8f21bd0090052e740944f9397e2be5ac7957ded7 upstream.
The csum_partial_copy_generic() function saves the PowerPC non-volatile
r14, r15, and r16 registers for the main checksum-and-copy loop.
Unfortunately, it fails to restore them upon error exit from this loop,
which results in silent corruption of these registers in the presumably
rare event of an access exception within that loop.
This commit therefore restores these register on error exit from the loop.
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Anton Blanchard <anton@xxxxxxxxx>
Signed-off-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/lib/checksum_64.S | 54 ++++++++++++++++++++++++++++++-----------
1 file changed, 40 insertions(+), 14 deletions(-)
--- a/arch/powerpc/lib/checksum_64.S
+++ b/arch/powerpc/lib/checksum_64.S
@@ -229,19 +229,35 @@ _GLOBAL(csum_partial)
blr
- .macro source
+ .macro srcnr
100:
.section __ex_table,"a"
.align 3
- .llong 100b,.Lsrc_error
+ .llong 100b,.Lsrc_error_nr
.previous
.endm
- .macro dest
+ .macro source
+150:
+ .section __ex_table,"a"
+ .align 3
+ .llong 150b,.Lsrc_error
+ .previous
+ .endm
+
+ .macro dstnr
200:
.section __ex_table,"a"
.align 3
- .llong 200b,.Ldest_error
+ .llong 200b,.Ldest_error_nr
+ .previous
+ .endm
+
+ .macro dest
+250:
+ .section __ex_table,"a"
+ .align 3
+ .llong 250b,.Ldest_error
.previous
.endm
@@ -277,11 +293,11 @@ _GLOBAL(csum_partial_copy_generic)
mtctr r6
1:
-source; lhz r6,0(r3) /* align to doubleword */
+srcnr; lhz r6,0(r3) /* align to doubleword */
subi r5,r5,2
addi r3,r3,2
adde r0,r0,r6
-dest; sth r6,0(r4)
+dstnr; sth r6,0(r4)
addi r4,r4,2
bdnz 1b
@@ -395,10 +411,10 @@ dest; std r16,56(r4)
mtctr r6
3:
-source; ld r6,0(r3)
+srcnr; ld r6,0(r3)
addi r3,r3,8
adde r0,r0,r6
-dest; std r6,0(r4)
+dstnr; std r6,0(r4)
addi r4,r4,8
bdnz 3b
@@ -408,10 +424,10 @@ dest; std r6,0(r4)
srdi. r6,r5,2
beq .Lcopy_tail_halfword
-source; lwz r6,0(r3)
+srcnr; lwz r6,0(r3)
addi r3,r3,4
adde r0,r0,r6
-dest; stw r6,0(r4)
+dstnr; stw r6,0(r4)
addi r4,r4,4
subi r5,r5,4
@@ -419,10 +435,10 @@ dest; stw r6,0(r4)
srdi. r6,r5,1
beq .Lcopy_tail_byte
-source; lhz r6,0(r3)
+srcnr; lhz r6,0(r3)
addi r3,r3,2
adde r0,r0,r6
-dest; sth r6,0(r4)
+dstnr; sth r6,0(r4)
addi r4,r4,2
subi r5,r5,2
@@ -430,10 +446,10 @@ dest; sth r6,0(r4)
andi. r6,r5,1
beq .Lcopy_finish
-source; lbz r6,0(r3)
+srcnr; lbz r6,0(r3)
sldi r9,r6,8 /* Pad the byte out to 16 bits */
adde r0,r0,r9
-dest; stb r6,0(r4)
+dstnr; stb r6,0(r4)
.Lcopy_finish:
addze r0,r0 /* add in final carry */
@@ -443,6 +459,11 @@ dest; stb r6,0(r4)
blr
.Lsrc_error:
+ ld r14,STK_REG(R14)(r1)
+ ld r15,STK_REG(R15)(r1)
+ ld r16,STK_REG(R16)(r1)
+ addi r1,r1,STACKFRAMESIZE
+.Lsrc_error_nr:
cmpdi 0,r7,0
beqlr
li r6,-EFAULT
@@ -450,6 +471,11 @@ dest; stb r6,0(r4)
blr
.Ldest_error:
+ ld r14,STK_REG(R14)(r1)
+ ld r15,STK_REG(R15)(r1)
+ ld r16,STK_REG(R16)(r1)
+ addi r1,r1,STACKFRAMESIZE
+.Ldest_error_nr:
cmpdi 0,r8,0
beqlr
li r6,-EFAULT
Patches currently in stable-queue which might be from paulmck@xxxxxxxxxxxxxxxxxx are
queue-3.0/powerpc-restore-registers-on-error-exit-from-csum_partial_copy_generic.patch
queue-3.0/powerpc-fix-parameter-clobber-in-csum_partial_copy_generic.patch
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