Commit a160e941 authored by Max Filippov's avatar Max Filippov
Browse files

xtensa: fix unaligned and load/store configuration interaction 



Unaligned exception handler is needed in configurations with hardware
support for unaligned access when the load/store exception handler is
enabled because such configurations would still raise an exception on
unaligned access through the instruction bus.

Fixes: f29cf776 ("xtensa: add load/store exception handler")
Signed-off-by: default avatarMax Filippov <jcmvbkbc@gmail.com>
parent bc8d5916

arch/xtensa/kernel/align.S

+14 −20
Original line number Original line Diff line number Diff line 
/*

/*

 * arch/xtensa/kernel/align.S

 * arch/xtensa/kernel/align.S

 *

 *

 * Handle unalignment exceptions in kernel space.

 * Handle unalignment and load/store exceptions.

 *

 *

 * This file is subject to the terms and conditions of the GNU General

 * This file is subject to the terms and conditions of the GNU General

 * Public License.  See the file "COPYING" in the main directory of

 * Public License.  See the file "COPYING" in the main directory of
@@ -26,20 +26,18 @@ 
#define LOAD_EXCEPTION_HANDLER

#define LOAD_EXCEPTION_HANDLER

#endif

#endif





#if XCHAL_UNALIGNED_STORE_EXCEPTION || defined LOAD_EXCEPTION_HANDLER

#if XCHAL_UNALIGNED_STORE_EXCEPTION || defined CONFIG_XTENSA_LOAD_STORE

#define STORE_EXCEPTION_HANDLER

#endif



#if defined LOAD_EXCEPTION_HANDLER || defined STORE_EXCEPTION_HANDLER

#define ANY_EXCEPTION_HANDLER

#define ANY_EXCEPTION_HANDLER

#endif

#endif





#if XCHAL_HAVE_WINDOWED

#if XCHAL_HAVE_WINDOWED && defined CONFIG_MMU

#define UNALIGNED_USER_EXCEPTION

#define UNALIGNED_USER_EXCEPTION

#endif

#endif





/*  First-level exception handler for unaligned exceptions.

 *

 *  Note: This handler works only for kernel exceptions.  Unaligned user

 *        access should get a seg fault.

 */



/* Big and little endian 16-bit values are located in

/* Big and little endian 16-bit values are located in

 * different halves of a register.  HWORD_START helps to

 * different halves of a register.  HWORD_START helps to

 * abstract the notion of extracting a 16-bit value from a

 * abstract the notion of extracting a 16-bit value from a
@@ -228,8 +226,6 @@ ENDPROC(fast_load_store) 
#ifdef ANY_EXCEPTION_HANDLER

#ifdef ANY_EXCEPTION_HANDLER

ENTRY(fast_unaligned)

ENTRY(fast_unaligned)





#if XCHAL_UNALIGNED_LOAD_EXCEPTION || XCHAL_UNALIGNED_STORE_EXCEPTION



	call0	.Lsave_and_load_instruction

	call0	.Lsave_and_load_instruction





	/* Analyze the instruction (load or store?). */

	/* Analyze the instruction (load or store?). */
@@ -244,8 +240,7 @@ ENTRY(fast_unaligned) 
	/* 'store indicator bit' not set, jump */

	/* 'store indicator bit' not set, jump */

	_bbci.l	a4, OP1_SI_BIT + INSN_OP1, .Lload

	_bbci.l	a4, OP1_SI_BIT + INSN_OP1, .Lload





#endif

#ifdef STORE_EXCEPTION_HANDLER

#if XCHAL_UNALIGNED_STORE_EXCEPTION





	/* Store: Jump to table entry to get the value in the source register.*/

	/* Store: Jump to table entry to get the value in the source register.*/
@@ -254,7 +249,7 @@ ENTRY(fast_unaligned) 
	addx8	a5, a6, a5

	addx8	a5, a6, a5

	jx	a5			# jump into table

	jx	a5			# jump into table

#endif

#endif

#if XCHAL_UNALIGNED_LOAD_EXCEPTION

#ifdef LOAD_EXCEPTION_HANDLER





	/* Load: Load memory address. */

	/* Load: Load memory address. */
@@ -328,7 +323,7 @@ ENTRY(fast_unaligned) 
	mov	a14, a3		;	_j .Lexit;	.align 8

	mov	a14, a3		;	_j .Lexit;	.align 8

	mov	a15, a3		;	_j .Lexit;	.align 8

	mov	a15, a3		;	_j .Lexit;	.align 8

#endif

#endif

#if XCHAL_UNALIGNED_STORE_EXCEPTION

#ifdef STORE_EXCEPTION_HANDLER

.Lstore_table:

.Lstore_table:

	l32i	a3, a2, PT_AREG0;	_j .Lstore_w;	.align 8

	l32i	a3, a2, PT_AREG0;	_j .Lstore_w;	.align 8

	mov	a3, a1;			_j .Lstore_w;	.align 8	# fishy??

	mov	a3, a1;			_j .Lstore_w;	.align 8	# fishy??
@@ -348,7 +343,6 @@ ENTRY(fast_unaligned) 
	mov	a3, a15		;	_j .Lstore_w;	.align 8

	mov	a3, a15		;	_j .Lstore_w;	.align 8

#endif

#endif





#ifdef ANY_EXCEPTION_HANDLER

	/* We cannot handle this exception. */

	/* We cannot handle this exception. */





	.extern _kernel_exception

	.extern _kernel_exception
@@ -377,8 +371,8 @@ ENTRY(fast_unaligned) 




2:	movi	a0, _user_exception

2:	movi	a0, _user_exception

	jx	a0

	jx	a0

#endif



#if XCHAL_UNALIGNED_STORE_EXCEPTION

#ifdef STORE_EXCEPTION_HANDLER





	# a7: instruction pointer, a4: instruction, a3: value

	# a7: instruction pointer, a4: instruction, a3: value

.Lstore_w:

.Lstore_w:
@@ -444,7 +438,7 @@ ENTRY(fast_unaligned) 
	s32i	a6, a4, 4

	s32i	a6, a4, 4

#endif

#endif

#endif

#endif

#ifdef ANY_EXCEPTION_HANDLER



.Lexit:

.Lexit:

#if XCHAL_HAVE_LOOPS

#if XCHAL_HAVE_LOOPS

	rsr	a4, lend		# check if we reached LEND

	rsr	a4, lend		# check if we reached LEND
@@ -539,7 +533,7 @@ ENTRY(fast_unaligned) 
	__src_b	a4, a4, a5	# a4 has the instruction

	__src_b	a4, a4, a5	# a4 has the instruction





	ret

	ret

#endif



ENDPROC(fast_unaligned)

ENDPROC(fast_unaligned)





ENTRY(fast_unaligned_fixup)

ENTRY(fast_unaligned_fixup)

arch/xtensa/kernel/traps.c

+2 −1
Original line number Original line Diff line number Diff line
@@ -102,7 +102,8 @@ static dispatch_init_table_t __initdata dispatch_init_table[] = { 
#endif

#endif

{ EXCCAUSE_INTEGER_DIVIDE_BY_ZERO, 0,	   do_div0 },

{ EXCCAUSE_INTEGER_DIVIDE_BY_ZERO, 0,	   do_div0 },

/* EXCCAUSE_PRIVILEGED unhandled */

/* EXCCAUSE_PRIVILEGED unhandled */

#if XCHAL_UNALIGNED_LOAD_EXCEPTION || XCHAL_UNALIGNED_STORE_EXCEPTION

#if XCHAL_UNALIGNED_LOAD_EXCEPTION || XCHAL_UNALIGNED_STORE_EXCEPTION || \

		IS_ENABLED(CONFIG_XTENSA_LOAD_STORE)

#ifdef CONFIG_XTENSA_UNALIGNED_USER

#ifdef CONFIG_XTENSA_UNALIGNED_USER

{ EXCCAUSE_UNALIGNED,		USER,	   fast_unaligned },

{ EXCCAUSE_UNALIGNED,		USER,	   fast_unaligned },

#endif

#endif