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Commit 409c1b25 authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Helge Deller
Browse files

parisc: fix bugs in pa_memcpy 



The patch 554bfece ("parisc: Fix access
fault handling in pa_memcpy()") reimplements the pa_memcpy function.
Unfortunatelly, it makes the kernel unbootable. The crash happens in the
function ide_complete_cmd where memcpy is called with the same source
and destination address.

This patch fixes a few bugs in pa_memcpy:

* When jumping to .Lcopy_loop_16 for the first time, don't skip the
  instruction "ldi 31,t0" (this bug made the kernel unbootable)
* Use the COND macro when comparing length, so that the comparison is
  64-bit (a theoretical issue, in case the length is greater than
  0xffffffff)
* Don't use the COND macro after the "extru" instruction (the PA-RISC
  specification says that the upper 32-bits of extru result are undefined,
  although they are set to zero in practice)
* Fix exception addresses in .Lcopy16_fault and .Lcopy8_fault
* Rename .Lcopy_loop_4 to .Lcopy_loop_8 (so that it is consistent with
  .Lcopy8_fault)

Cc: <stable@vger.kernel.org> # v4.9+
Fixes: 554bfece ("parisc: Fix access fault handling in pa_memcpy()")
Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarHelge Deller <deller@gmx.de>
parent 1bf4b126

arch/parisc/lib/lusercopy.S

+14 −13
Original line number Diff line number Diff line
@@ -201,7 +201,7 @@ ENTRY_CFI(pa_memcpy) 
	add	dst,len,end



	/* short copy with less than 16 bytes? */

	cmpib,>>=,n 15,len,.Lbyte_loop

	cmpib,COND(>>=),n 15,len,.Lbyte_loop



	/* same alignment? */

	xor	src,dst,t0
@@ -216,7 +216,7 @@ ENTRY_CFI(pa_memcpy) 
	/* loop until we are 64-bit aligned */

.Lalign_loop64:

	extru	dst,31,3,t1

	cmpib,=,n	0,t1,.Lcopy_loop_16

	cmpib,=,n	0,t1,.Lcopy_loop_16_start

20:	ldb,ma	1(srcspc,src),t1

21:	stb,ma	t1,1(dstspc,dst)

	b	.Lalign_loop64
@@ -225,6 +225,7 @@ ENTRY_CFI(pa_memcpy) 
	ASM_EXCEPTIONTABLE_ENTRY(20b,.Lcopy_done)

	ASM_EXCEPTIONTABLE_ENTRY(21b,.Lcopy_done)



.Lcopy_loop_16_start:

	ldi	31,t0

.Lcopy_loop_16:

	cmpb,COND(>>=),n t0,len,.Lword_loop
@@ -267,7 +268,7 @@ ENTRY_CFI(pa_memcpy) 
	/* loop until we are 32-bit aligned */

.Lalign_loop32:

	extru	dst,31,2,t1

	cmpib,=,n	0,t1,.Lcopy_loop_4

	cmpib,=,n	0,t1,.Lcopy_loop_8

20:	ldb,ma	1(srcspc,src),t1

21:	stb,ma	t1,1(dstspc,dst)

	b	.Lalign_loop32
@@ -277,7 +278,7 @@ ENTRY_CFI(pa_memcpy) 
	ASM_EXCEPTIONTABLE_ENTRY(21b,.Lcopy_done)





.Lcopy_loop_4:

.Lcopy_loop_8:

	cmpib,COND(>>=),n 15,len,.Lbyte_loop



10:	ldw	0(srcspc,src),t1
@@ -299,7 +300,7 @@ ENTRY_CFI(pa_memcpy) 
	ASM_EXCEPTIONTABLE_ENTRY(16b,.Lcopy_done)

	ASM_EXCEPTIONTABLE_ENTRY(17b,.Lcopy_done)



	b	.Lcopy_loop_4

	b	.Lcopy_loop_8

	ldo	-16(len),len



.Lbyte_loop:
@@ -324,7 +325,7 @@ ENTRY_CFI(pa_memcpy) 
.Lunaligned_copy:

	/* align until dst is 32bit-word-aligned */

	extru	dst,31,2,t1

	cmpib,COND(=),n	0,t1,.Lcopy_dstaligned

	cmpib,=,n	0,t1,.Lcopy_dstaligned

20:	ldb	0(srcspc,src),t1

	ldo	1(src),src

21:	stb,ma	t1,1(dstspc,dst)
@@ -362,7 +363,7 @@ ENTRY_CFI(pa_memcpy) 
	cmpiclr,<> 1,t0,%r0

	b,n .Lcase1

.Lcase0:

	cmpb,= %r0,len,.Lcda_finish

	cmpb,COND(=) %r0,len,.Lcda_finish

	nop



1:	ldw,ma 4(srcspc,src), a3
@@ -376,7 +377,7 @@ ENTRY_CFI(pa_memcpy) 
1:	ldw,ma 4(srcspc,src), a3

	ASM_EXCEPTIONTABLE_ENTRY(1b,.Lcda_rdfault)

	ldo -1(len),len

	cmpb,=,n %r0,len,.Ldo0

	cmpb,COND(=),n %r0,len,.Ldo0

.Ldo4:

1:	ldw,ma 4(srcspc,src), a0

	ASM_EXCEPTIONTABLE_ENTRY(1b,.Lcda_rdfault)
@@ -402,7 +403,7 @@ ENTRY_CFI(pa_memcpy) 
1:	stw,ma t0, 4(dstspc,dst)

	ASM_EXCEPTIONTABLE_ENTRY(1b,.Lcopy_done)

	ldo -4(len),len

	cmpb,<> %r0,len,.Ldo4

	cmpb,COND(<>) %r0,len,.Ldo4

	nop

.Ldo0:

	shrpw a2, a3, %sar, t0
@@ -436,14 +437,14 @@ ENTRY_CFI(pa_memcpy) 
	/* fault exception fixup handlers: */

#ifdef CONFIG_64BIT

.Lcopy16_fault:

10:	b	.Lcopy_done

	std,ma	t1,8(dstspc,dst)

	b	.Lcopy_done

10:	std,ma	t1,8(dstspc,dst)

	ASM_EXCEPTIONTABLE_ENTRY(10b,.Lcopy_done)

#endif



.Lcopy8_fault:

10:	b	.Lcopy_done

	stw,ma	t1,4(dstspc,dst)

	b	.Lcopy_done

10:	stw,ma	t1,4(dstspc,dst)

	ASM_EXCEPTIONTABLE_ENTRY(10b,.Lcopy_done)



	.exit