Commit 8f21bd00 authored by Paul E. McKenney's avatar Paul E. McKenney Committed by Benjamin Herrenschmidt
Browse files

powerpc: Restore registers on error exit from csum_partial_copy_generic() 



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: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: default avatarAnton Blanchard <anton@samba.org>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent d9813c36

arch/powerpc/lib/checksum_64.S

+40 −14
Original line number Diff line number Diff line
@@ -226,19 +226,35 @@ _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
@@ -274,11 +290,11 @@ _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
@@ -392,10 +408,10 @@ 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
@@ -405,10 +421,10 @@ 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
@@ -416,10 +432,10 @@ 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
@@ -427,10 +443,10 @@ 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 */
@@ -440,6 +456,11 @@ 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
@@ -447,6 +468,11 @@ 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

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