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Commit 88776c0e authored by Helge Deller's avatar Helge Deller
Browse files

parisc: Fix alignment of pa_tlb_lock in assembly on 32-bit SMP kernel 



Qemu for PARISC reported on a 32bit SMP parisc kernel strange failures
about "Not-handled unaligned insn 0x0e8011d6 and 0x0c2011c9."

Those opcodes evaluate to the ldcw() assembly instruction which requires
(on 32bit) an alignment of 16 bytes to ensure atomicity.

As it turns out, qemu is correct and in our assembly code in entry.S and
pacache.S we don't pay attention to the required alignment.

This patch fixes the problem by aligning the lock offset in assembly
code in the same manner as we do in our C-code.

Signed-off-by: default avatarHelge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org> # v4.0+
parent 28df2f83

arch/parisc/include/asm/ldcw.h

+2 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
   for the semaphore.  */



#define __PA_LDCW_ALIGNMENT	16

#define __PA_LDCW_ALIGN_ORDER	4

#define __ldcw_align(a) ({					\

	unsigned long __ret = (unsigned long) &(a)->lock[0];	\

	__ret = (__ret + __PA_LDCW_ALIGNMENT - 1)		\
@@ -29,6 +30,7 @@ 
   ldcd). */



#define __PA_LDCW_ALIGNMENT	4

#define __PA_LDCW_ALIGN_ORDER	2

#define __ldcw_align(a) (&(a)->slock)

#define __LDCW	"ldcw,co"

arch/parisc/kernel/entry.S

+11 −2
Original line number Diff line number Diff line
@@ -35,6 +35,7 @@ 
#include <asm/pgtable.h>

#include <asm/signal.h>

#include <asm/unistd.h>

#include <asm/ldcw.h>

#include <asm/thread_info.h>



#include <linux/linkage.h>
@@ -46,6 +47,14 @@ 
#endif



	.import		pa_tlb_lock,data

	.macro  load_pa_tlb_lock reg

#if __PA_LDCW_ALIGNMENT > 4

	load32	PA(pa_tlb_lock) + __PA_LDCW_ALIGNMENT-1, \reg

	depi	0,31,__PA_LDCW_ALIGN_ORDER, \reg

#else

	load32	PA(pa_tlb_lock), \reg

#endif

	.endm



	/* space_to_prot macro creates a prot id from a space id */
@@ -457,7 +466,7 @@ 
	.macro		tlb_lock	spc,ptp,pte,tmp,tmp1,fault

#ifdef CONFIG_SMP

	cmpib,COND(=),n	0,\spc,2f

	load32		PA(pa_tlb_lock),\tmp

	load_pa_tlb_lock \tmp

1:	LDCW		0(\tmp),\tmp1

	cmpib,COND(=)	0,\tmp1,1b

	nop
@@ -480,7 +489,7 @@ 
	/* Release pa_tlb_lock lock. */

	.macro		tlb_unlock1	spc,tmp

#ifdef CONFIG_SMP

	load32		PA(pa_tlb_lock),\tmp

	load_pa_tlb_lock \tmp

	tlb_unlock0	\spc,\tmp

#endif

	.endm

arch/parisc/kernel/pacache.S

+7 −2
Original line number Diff line number Diff line
@@ -36,6 +36,7 @@ 
#include <asm/assembly.h>

#include <asm/pgtable.h>

#include <asm/cache.h>

#include <asm/ldcw.h>

#include <linux/linkage.h>



	.text
@@ -333,8 +334,12 @@ ENDPROC_CFI(flush_data_cache_local) 


	.macro	tlb_lock	la,flags,tmp

#ifdef CONFIG_SMP

	ldil		L%pa_tlb_lock,%r1

	ldo		R%pa_tlb_lock(%r1),\la

#if __PA_LDCW_ALIGNMENT > 4

	load32		pa_tlb_lock + __PA_LDCW_ALIGNMENT-1, \la

	depi		0,31,__PA_LDCW_ALIGN_ORDER, \la

#else

	load32		pa_tlb_lock, \la

#endif

	rsm		PSW_SM_I,\flags

1:	LDCW		0(\la),\tmp

	cmpib,<>,n	0,\tmp,3f