sh: Exception vector rework and SH-2/SH-2A support.

This splits out common bits from the existing exception handler for
use between SH-2/SH-2A and SH-3/4, and adds support for the SH-2/2A
exceptions.

Signed-off-by: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 325 insertions, 0 deletions

diff --git a/arch/sh/kernel/cpu/sh2/entry.S b/arch/sh/kernel/cpu/sh2/entry.S
new file mode 100644
index 000000000000..298d9191909d
--- /dev/null
+++ b/arch/sh/kernel/cpu/sh2/entry.S
@@ -0,0 +1,325 @@
+/*
+ * arch/sh/kernel/cpu/sh2/entry.S
+ *
+ * The SH-2 exception entry
+ *
+ * Copyright (C) 2005,2006 Yoshinori Sato
+ * Copyright (C) 2005  AXE,Inc.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/linkage.h>
+#include <asm/asm-offsets.h>
+#include <asm/thread_info.h>
+#include <asm/cpu/mmu_context.h>
+#include <asm/unistd.h>
+#include <asm/errno.h>
+#include <asm/page.h>
+	
+/* Offsets to the stack */
+OFF_R0  =  0		/* Return value. New ABI also arg4 */
+OFF_R1  =  4     	/* New ABI: arg5 */
+OFF_R2  =  8     	/* New ABI: arg6 */
+OFF_R3  =  12     	/* New ABI: syscall_nr */
+OFF_R4  =  16     	/* New ABI: arg0 */
+OFF_R5  =  20     	/* New ABI: arg1 */
+OFF_R6  =  24     	/* New ABI: arg2 */
+OFF_R7  =  28     	/* New ABI: arg3 */
+OFF_SP	=  (15*4)
+OFF_PC  =  (16*4)
+OFF_SR	=  (16*4+2*4)
+OFF_TRA	=  (16*4+6*4)
+
+#include <asm/entry-macros.S>
+
+ENTRY(exception_handler)
+	! already saved r0/r1
+	mov.l	r2,@-sp
+	mov.l	r3,@-sp
+	mov	r0,r1
+	cli
+	mov.l	$cpu_mode,r2
+	mov.l	@r2,r0
+	mov.l	@(5*4,r15),r3	! previous SR
+	shll2	r3		! set "S" flag
+	rotl	r0		! T <- "S" flag
+	rotl	r0		! "S" flag is LSB
+	rotcr	r3		! T -> r3:b30
+	shlr	r3
+	shlr	r0
+	bt/s	1f
+	 mov.l	r3,@(5*4,r15)	! copy cpu mode to SR
+	! switch to kernel mode
+	mov	#1,r0
+	rotr	r0
+	rotr	r0
+	mov.l	r0,@r2		! enter kernel mode
+	mov.l	$current_thread_info,r2
+	mov.l	@r2,r2
+	mov	#0x20,r0
+	shll8	r0
+	add	r2,r0
+	mov	r15,r2		! r2 = user stack top
+	mov	r0,r15		! switch kernel stack
+	add	#-4,r15		! dummy
+	mov.l	r1,@-r15	! TRA
+	sts.l	macl, @-r15
+	sts.l	mach, @-r15
+	stc.l	gbr, @-r15
+	mov.l	@(4*4,r2),r0
+	mov.l	@(5*4,r2),r1
+	mov.l	r1,@-r15	! original SR
+	sts.l	pr,@-r15
+	mov.l	r0,@-r15	! original PC
+	mov	r2,r3
+	add	#(4+2)*4,r3	! rewind r0 - r3 + exception frame
+	mov.l	r3,@-r15	! original SP
+	mov.l	r14,@-r15
+	mov.l	r13,@-r15
+	mov.l	r12,@-r15
+	mov.l	r11,@-r15
+	mov.l	r10,@-r15
+	mov.l	r9,@-r15
+	mov.l	r8,@-r15
+	mov.l	r7,@-r15
+	mov.l	r6,@-r15
+	mov.l	r5,@-r15
+	mov.l	r4,@-r15
+	mov	r2,r8		! copy user -> kernel stack
+	mov.l	@r8+,r3
+	mov.l	r3,@-r15
+	mov.l	@r8+,r2
+	mov.l	r2,@-r15
+	mov.l	@r8+,r1
+	mov.l	r1,@-r15
+	mov.l	@r8+,r0
+	bra	2f
+	 mov.l	r0,@-r15
+1:
+	! in kernel exception
+	mov	#(22-4-4-1)*4+4,r0
+	mov	r15,r2
+	sub	r0,r15
+	mov.l	@r2+,r0		! old R3
+	mov.l	r0,@-r15	
+	mov.l	@r2+,r0		! old R2
+	mov.l	r0,@-r15	
+	mov.l	@r2+,r0		! old R1
+	mov.l	r0,@-r15	
+	mov.l	@r2+,r0		! old R0
+	mov.l	r0,@-r15	
+	mov.l	@r2+,r3		! old PC
+	mov.l	@r2+,r0		! old SR
+	add	#-4,r2		! exception frame stub (sr)
+	mov.l	r1,@-r2		! TRA
+	sts.l	macl, @-r2
+	sts.l	mach, @-r2
+	stc.l	gbr, @-r2
+	mov.l	r0,@-r2		! save old SR
+	sts.l	pr,@-r2
+	mov.l	r3,@-r2		! save old PC
+	mov	r2,r0
+	add	#8*4,r0
+	mov.l	r0,@-r2		! save old SP
+	mov.l	r14,@-r2
+	mov.l	r13,@-r2
+	mov.l	r12,@-r2
+	mov.l	r11,@-r2
+	mov.l	r10,@-r2
+	mov.l	r9,@-r2
+	mov.l	r8,@-r2
+	mov.l	r7,@-r2
+	mov.l	r6,@-r2
+	mov.l	r5,@-r2
+	mov.l	r4,@-r2
+	mov.l	@(OFF_R0,r15),r0
+	mov.l	@(OFF_R1,r15),r1
+	mov.l	@(OFF_R2,r15),r2
+	mov.l	@(OFF_R3,r15),r3
+2:
+	mov	#OFF_TRA,r8
+	add	r15,r8
+	mov.l	@r8,r9	
+	mov	#64,r8
+	cmp/hs	r8,r9
+	bt	interrupt_entry	! vec >= 64 is interrupt
+	mov	#32,r8
+	cmp/hs	r8,r9
+	bt	trap_entry	! 64 > vec >= 32  is trap
+	mov.l	4f,r8
+	mov	r9,r4
+	shll2	r9
+	add	r9,r8
+	mov.l	@r8,r8
+	mov	#0,r9
+	cmp/eq	r9,r8
+	bf	3f
+	mov.l	8f,r8		! unhandled exception
+3:
+	mov.l	5f,r10
+	jmp	@r8
+	 lds	r10,pr
+
+interrupt_entry:
+	mov	r9,r4
+	mov.l	6f,r9
+	mov.l	7f,r8
+	jmp	@r8
+	 lds	r9,pr
+
+	.align	2
+4:	.long	exception_handling_table
+5:	.long	ret_from_exception
+6:	.long	ret_from_irq
+7:	.long	do_IRQ
+8:	.long	do_exception_error
+	
+trap_entry:	
+	add	#-0x10,r9
+	shll2	r9			! TRA
+	mov	#OFF_TRA,r8
+	add	r15,r8
+	mov.l	r9,@r8
+	mov	r9,r8
+	sti
+	bra	system_call
+	 nop
+	
+	.align	2
+1:	.long	syscall_exit
+2:	.long	break_point_trap_software
+3:	.long	NR_syscalls
+4:	.long	sys_call_table
+
+#if defined(CONFIG_SH_STANDARD_BIOS)
+	/* Unwind the stack and jmp to the debug entry */
+debug_kernel_fw:
+	mov	r15,r0
+	add	#(22-4)*4-4,r0
+	ldc.l	@r0+,gbr
+	lds.l	@r0+,mach
+	lds.l	@r0+,macl
+	mov	r15,r0
+	mov.l	@(OFF_SP,r0),r1
+	mov	#OFF_SR,r2
+	mov.l	@(r0,r2),r3
+	mov.l	r3,@-r1
+	mov	#OFF_SP,r2
+	mov.l	@(r0,r2),r3
+	mov.l	r3,@-r1
+	mov	r15,r0
+	add	#(22-4)*4-8,r0
+	mov.l	1f,r2
+	mov.l	@r2,r2
+	stc	sr,r3
+	mov.l	r2,@r0
+	mov.l	r3,@r0
+	mov.l	r1,@(8,r0)	
+	mov.l	@r15+, r0
+	mov.l	@r15+, r1
+	mov.l	@r15+, r2
+	mov.l	@r15+, r3
+	mov.l	@r15+, r4
+	mov.l	@r15+, r5
+	mov.l	@r15+, r6
+	mov.l	@r15+, r7
+	mov.l	@r15+, r8
+	mov.l	@r15+, r9
+	mov.l	@r15+, r10
+	mov.l	@r15+, r11
+	mov.l	@r15+, r12
+	mov.l	@r15+, r13
+	mov.l	@r15+, r14
+	add	#8,r15
+	lds.l	@r15+, pr
+	rte
+	 mov.l	@r15+,r15
+	.align	2
+1:	.long	gdb_vbr_vector
+#endif /* CONFIG_SH_STANDARD_BIOS */
+
+ENTRY(address_error_handler)
+	mov	r15,r4				! regs
+	add	#4,r4
+	mov	#OFF_PC,r0
+	mov.l	@(r0,r15),r6			! pc
+	mov.l	1f,r0
+	jmp	@r0
+	 mov	#0,r5				! writeaccess is unknown
+	.align	2
+
+1:	.long	do_address_error
+
+restore_all:
+	cli
+	mov	r15,r0
+	mov.l	$cpu_mode,r2
+	mov	#OFF_SR,r3
+	mov.l	@(r0,r3),r1
+	mov.l	r1,@r2
+	shll2	r1				! clear MD bit
+	shlr2	r1
+	mov.l	@(OFF_SP,r0),r2
+	add	#-8,r2
+	mov.l	r2,@(OFF_SP,r0)			! point exception frame top
+	mov.l	r1,@(4,r2)			! set sr
+	mov	#OFF_PC,r3
+	mov.l	@(r0,r3),r1
+	mov.l	r1,@r2				! set pc
+	add	#4*16+4,r0
+	lds.l	@r0+,pr
+	add	#4,r0				! skip sr
+	ldc.l	@r0+,gbr
+	lds.l	@r0+,mach
+	lds.l	@r0+,macl
+	get_current_thread_info r0, r1
+	mov.l	$current_thread_info,r1
+	mov.l	r0,@r1
+	mov.l	@r15+,r0
+	mov.l	@r15+,r1
+	mov.l	@r15+,r2
+	mov.l	@r15+,r3
+	mov.l	@r15+,r4
+	mov.l	@r15+,r5
+	mov.l	@r15+,r6
+	mov.l	@r15+,r7
+	mov.l	@r15+,r8
+	mov.l	@r15+,r9
+	mov.l	@r15+,r10
+	mov.l	@r15+,r11
+	mov.l	@r15+,r12
+	mov.l	@r15+,r13
+	mov.l	@r15+,r14
+	mov.l	@r15,r15
+	rte
+	 nop
+2:
+	mov.l	1f,r8
+	mov.l	2f,r9
+	jmp	@r9
+	 lds	r8,pr
+
+	.align	2
+$current_thread_info:
+	.long	__current_thread_info
+$cpu_mode:	
+	.long	__cpu_mode
+		
+! common exception handler
+#include "../../entry-common.S"
+	
+	.data
+! cpu operation mode 
+! bit30 = MD (compatible SH3/4)
+__cpu_mode:
+	.long	0x40000000
+		
+	.section	.bss
+__current_thread_info:
+	.long	0
+
+ENTRY(exception_handling_table)
+	.space	4*32