1/*
2 * arch/sh/kernel/cpu/sh2/entry.S
3 *
4 * The SH-2 exception entry
5 *
6 * Copyright (C) 2005-2008 Yoshinori Sato
7 * Copyright (C) 2005  AXE,Inc.
8 *
9 * This file is subject to the terms and conditions of the GNU General Public
10 * License.  See the file "COPYING" in the main directory of this archive
11 * for more details.
12 */
13
14#include <linux/linkage.h>
15#include <asm/asm-offsets.h>
16#include <asm/thread_info.h>
17#include <cpu/mmu_context.h>
18#include <asm/unistd.h>
19#include <asm/errno.h>
20#include <asm/page.h>
21
22/* Offsets to the stack */
23OFF_R0  =  0		/* Return value. New ABI also arg4 */
24OFF_R1  =  4     	/* New ABI: arg5 */
25OFF_R2  =  8     	/* New ABI: arg6 */
26OFF_R3  =  12     	/* New ABI: syscall_nr */
27OFF_R4  =  16     	/* New ABI: arg0 */
28OFF_R5  =  20     	/* New ABI: arg1 */
29OFF_R6  =  24     	/* New ABI: arg2 */
30OFF_R7  =  28     	/* New ABI: arg3 */
31OFF_SP	=  (15*4)
32OFF_PC  =  (16*4)
33OFF_SR	=  (16*4+2*4)
34OFF_TRA	=  (16*4+6*4)
35
36#include <asm/entry-macros.S>
37
38ENTRY(exception_handler)
39	! stack
40	! r0 <- point sp
41	! r1
42	! pc
43	! sr
44	! r0 = temporary
45	! r1 = vector (pseudo EXPEVT / INTEVT / TRA)
46	mov.l	r2,@-sp
47	mov.l	r3,@-sp
48	cli
49	mov.l	$cpu_mode,r2
50	mov.l	@r2,r0
51	mov.l	@(5*4,r15),r3	! previous SR
52	or	r0,r3		! set MD
53	tst	r0,r0
54	bf/s	1f		! previous mode check
55	 mov.l	r3,@(5*4,r15)	! update SR
56	! switch to kernel mode
57	mov.l	__md_bit,r0
58	mov.l	r0,@r2		! enter kernel mode
59	mov.l	$current_thread_info,r2
60	mov.l	@r2,r2
61	mov	#(THREAD_SIZE >> 8),r0
62	shll8	r0
63	add	r2,r0
64	mov	r15,r2		! r2 = user stack top
65	mov	r0,r15		! switch kernel stack
66	mov.l	r1,@-r15	! TRA
67	sts.l	macl, @-r15
68	sts.l	mach, @-r15
69	stc.l	gbr, @-r15
70	mov.l	@(5*4,r2),r0
71	mov.l	r0,@-r15	! original SR
72	sts.l	pr,@-r15
73	mov.l	@(4*4,r2),r0
74	mov.l	r0,@-r15	! original PC
75	mov	r2,r3
76	add	#(4+2)*4,r3	! rewind r0 - r3 + exception frame
77	mov.l	r3,@-r15	! original SP
78	mov.l	r14,@-r15
79	mov.l	r13,@-r15
80	mov.l	r12,@-r15
81	mov.l	r11,@-r15
82	mov.l	r10,@-r15
83	mov.l	r9,@-r15
84	mov.l	r8,@-r15
85	mov.l	r7,@-r15
86	mov.l	r6,@-r15
87	mov.l	r5,@-r15
88	mov.l	r4,@-r15
89	mov	r1,r9		! save TRA
90	mov	r2,r8		! copy user -> kernel stack
91	mov.l	@(0,r8),r3
92	mov.l	r3,@-r15
93	mov.l	@(4,r8),r2
94	mov.l	r2,@-r15
95	mov.l	@(12,r8),r1
96	mov.l	r1,@-r15
97	mov.l	@(8,r8),r0
98	bra	2f
99	 mov.l	r0,@-r15
1001:
101	! in kernel exception
102	mov	#(22-4-4-1)*4+4,r0
103	mov	r15,r2
104	sub	r0,r15
105	mov.l	@r2+,r0		! old R3
106	mov.l	r0,@-r15
107	mov.l	@r2+,r0		! old R2
108	mov.l	r0,@-r15
109	mov.l	@(4,r2),r0	! old R1
110	mov.l	r0,@-r15
111	mov.l	@r2,r0		! old R0
112	mov.l	r0,@-r15
113	add	#8,r2
114	mov.l	@r2+,r3		! old PC
115	mov.l	@r2+,r0		! old SR
116	add	#-4,r2		! exception frame stub (sr)
117	mov.l	r1,@-r2		! TRA
118	sts.l	macl, @-r2
119	sts.l	mach, @-r2
120	stc.l	gbr, @-r2
121	mov.l	r0,@-r2		! save old SR
122	sts.l	pr,@-r2
123	mov.l	r3,@-r2		! save old PC
124	mov	r2,r0
125	add	#8*4,r0
126	mov.l	r0,@-r2		! save old SP
127	mov.l	r14,@-r2
128	mov.l	r13,@-r2
129	mov.l	r12,@-r2
130	mov.l	r11,@-r2
131	mov.l	r10,@-r2
132	mov.l	r9,@-r2
133	mov.l	r8,@-r2
134	mov.l	r7,@-r2
135	mov.l	r6,@-r2
136	mov.l	r5,@-r2
137	mov.l	r4,@-r2
138	mov	r1,r9
139	mov.l	@(OFF_R0,r15),r0
140	mov.l	@(OFF_R1,r15),r1
141	mov.l	@(OFF_R2,r15),r2
142	mov.l	@(OFF_R3,r15),r3
1432:
144	mov	#64,r8
145	cmp/hs	r8,r9
146	bt	interrupt_entry	! vec >= 64 is interrupt
147	mov	#32,r8
148	cmp/hs	r8,r9
149	bt	trap_entry	! 64 > vec >= 32  is trap
150
151	mov.l	4f,r8
152	mov	r9,r4
153	shll2	r9
154	add	r9,r8
155	mov.l	@r8,r8		! exception handler address
156	tst	r8,r8
157	bf	3f
158	mov.l	8f,r8		! unhandled exception
1593:
160	mov.l	5f,r10
161	jmp	@r8
162	 lds	r10,pr
163
164interrupt_entry:
165	mov	r9,r4
166	mov	r15,r5
167	mov.l	6f,r9
168	mov.l	7f,r8
169	jmp	@r8
170	 lds	r9,pr
171
172	.align	2
1734:	.long	exception_handling_table
1745:	.long	ret_from_exception
1756:	.long	ret_from_irq
1767:	.long	do_IRQ
1778:	.long	exception_error
178
179trap_entry:
180	mov	#0x30,r8
181	cmp/ge	r8,r9		! vector 0x20-0x2f is systemcall
182	bt	1f
183	add	#-0x10,r9	! convert SH2 to SH3/4 ABI
1841:
185	shll2	r9			! TRA
186	bra	system_call	! jump common systemcall entry
187	 mov	r9,r8
188
189#if defined(CONFIG_SH_STANDARD_BIOS)
190	/* Unwind the stack and jmp to the debug entry */
191ENTRY(sh_bios_handler)
192	mov	r15,r0
193	add	#(22-4)*4-4,r0
194	ldc.l	@r0+,gbr
195	lds.l	@r0+,mach
196	lds.l	@r0+,macl
197	mov	r15,r0
198	mov.l	@(OFF_SP,r0),r1
199	mov	#OFF_SR,r2
200	mov.l	@(r0,r2),r3
201	mov.l	r3,@-r1
202	mov	#OFF_SP,r2
203	mov.l	@(r0,r2),r3
204	mov.l	r3,@-r1
205	mov	r15,r0
206	add	#(22-4)*4-8,r0
207	mov.l	1f,r2
208	mov.l	@r2,r2
209	stc	sr,r3
210	mov.l	r2,@r0
211	mov.l	r3,@(4,r0)
212	mov.l	r1,@(8,r0)
213	mov.l	@r15+, r0
214	mov.l	@r15+, r1
215	mov.l	@r15+, r2
216	mov.l	@r15+, r3
217	mov.l	@r15+, r4
218	mov.l	@r15+, r5
219	mov.l	@r15+, r6
220	mov.l	@r15+, r7
221	mov.l	@r15+, r8
222	mov.l	@r15+, r9
223	mov.l	@r15+, r10
224	mov.l	@r15+, r11
225	mov.l	@r15+, r12
226	mov.l	@r15+, r13
227	mov.l	@r15+, r14
228	add	#8,r15
229	lds.l	@r15+, pr
230	mov.l	@r15+,r15
231	rte
232	 nop
233	.align	2
2341:	.long	gdb_vbr_vector
235#endif /* CONFIG_SH_STANDARD_BIOS */
236
237ENTRY(address_error_trap_handler)
238	mov	r15,r4				! regs
239	mov	#OFF_PC,r0
240	mov.l	@(r0,r15),r6			! pc
241	mov.l	1f,r0
242	jmp	@r0
243	 mov	#0,r5				! writeaccess is unknown
244
245	.align	2
2461:	.long	do_address_error
247
248restore_all:
249	stc	sr,r0
250	or	#0xf0,r0
251	ldc	r0,sr				! all interrupt block (same BL = 1)
252	! restore special register
253	! overlap exception frame
254	mov	r15,r0
255	add	#17*4,r0
256	lds.l	@r0+,pr
257	add	#4,r0
258	ldc.l	@r0+,gbr
259	lds.l	@r0+,mach
260	lds.l	@r0+,macl
261	mov	r15,r0
262	mov.l	$cpu_mode,r2
263	mov	#OFF_SR,r3
264	mov.l	@(r0,r3),r1
265	mov.l	__md_bit,r3
266	and	r1,r3				! copy MD bit
267	mov.l	r3,@r2
268	shll2	r1				! clear MD bit
269	shlr2	r1
270	mov.l	@(OFF_SP,r0),r2
271	add	#-8,r2
272	mov.l	r2,@(OFF_SP,r0)			! point exception frame top
273	mov.l	r1,@(4,r2)			! set sr
274	mov	#OFF_PC,r3
275	mov.l	@(r0,r3),r1
276	mov.l	r1,@r2				! set pc
277	get_current_thread_info r0, r1
278	mov.l	$current_thread_info,r1
279	mov.l	r0,@r1
280	mov.l	@r15+,r0
281	mov.l	@r15+,r1
282	mov.l	@r15+,r2
283	mov.l	@r15+,r3
284	mov.l	@r15+,r4
285	mov.l	@r15+,r5
286	mov.l	@r15+,r6
287	mov.l	@r15+,r7
288	mov.l	@r15+,r8
289	mov.l	@r15+,r9
290	mov.l	@r15+,r10
291	mov.l	@r15+,r11
292	mov.l	@r15+,r12
293	mov.l	@r15+,r13
294	mov.l	@r15+,r14
295	mov.l	@r15,r15
296	rte
297	 nop
298
299	.align 2
300__md_bit:
301	.long	0x40000000
302$current_thread_info:
303	.long	__current_thread_info
304$cpu_mode:
305	.long	__cpu_mode
306
307! common exception handler
308#include "../../entry-common.S"
309
310	.data
311! cpu operation mode
312! bit30 = MD (compatible SH3/4)
313__cpu_mode:
314	.long	0x40000000
315
316	.section	.bss
317__current_thread_info:
318	.long	0
319
320ENTRY(exception_handling_table)
321	.space	4*32
322