2 * arch/sh/kernel/cpu/sh2/entry.S
4 * The SH-2 exception entry
6 * Copyright (C) 2005-2008 Yoshinori Sato
7 * Copyright (C) 2005 AXE,Inc.
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
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>
22 /* Offsets to the stack */
23 OFF_R0 = 0 /* Return value. New ABI also arg4 */
24 OFF_R1 = 4 /* New ABI: arg5 */
25 OFF_R2 = 8 /* New ABI: arg6 */
26 OFF_R3 = 12 /* New ABI: syscall_nr */
27 OFF_R4 = 16 /* New ABI: arg0 */
28 OFF_R5 = 20 /* New ABI: arg1 */
29 OFF_R6 = 24 /* New ABI: arg2 */
30 OFF_R7 = 28 /* New ABI: arg3 */
36 #include <asm/entry-macros.S>
38 ENTRY(exception_handler)
45 ! r1 = vector (pseudo EXPEVT / INTEVT / TRA)
51 mov.l @(5*4,r15),r3 ! previous SR
54 bf/s 1f ! previous mode check
55 mov.l r3,@(5*4,r15) ! update SR
56 ! switch to kernel mode
58 mov.l r0,@r2 ! enter kernel mode
59 mov.l $current_thread_info,r2
61 mov #(THREAD_SIZE >> 8),r0
64 mov r15,r2 ! r2 = user stack top
65 mov r0,r15 ! switch kernel stack
71 mov.l r0,@-r15 ! original SR
74 mov.l r0,@-r15 ! original PC
76 add #(4+2)*4,r3 ! rewind r0 - r3 + exception frame
77 mov.l r3,@-r15 ! original SP
90 mov r2,r8 ! copy user -> kernel stack
101 ! in kernel exception
102 mov #(22-4-4-1)*4+4,r0
105 mov.l @r2+,r0 ! old R3
107 mov.l @r2+,r0 ! old R2
109 mov.l @(4,r2),r0 ! old R1
111 mov.l @r2,r0 ! old R0
114 mov.l @r2+,r3 ! old PC
115 mov.l @r2+,r0 ! old SR
116 add #-4,r2 ! exception frame stub (sr)
121 mov.l r0,@-r2 ! save old SR
123 mov.l r3,@-r2 ! save old PC
126 mov.l r0,@-r2 ! save old SP
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
146 bt interrupt_entry ! vec >= 64 is interrupt
149 bt trap_entry ! 64 > vec >= 31 is trap
153 bt interrupt_entry ! 31 > vec >= 16 is interrupt
160 mov.l @r8,r8 ! exception handler address
163 mov.l 8f,r8 ! unhandled exception
178 4: .long exception_handling_table
179 5: .long ret_from_exception
180 6: .long ret_from_irq
182 8: .long exception_error
186 cmp/ge r8,r9 ! vector 0x1f-0x2f is systemcall
188 mov #0x1f,r9 ! convert to unified SH2/3/4 trap number
191 bra system_call ! jump common systemcall entry
194 #if defined(CONFIG_SH_STANDARD_BIOS)
195 /* Unwind the stack and jmp to the debug entry */
196 ENTRY(sh_bios_handler)
203 mov.l @(OFF_SP,r0),r1
239 1: .long gdb_vbr_vector
240 #endif /* CONFIG_SH_STANDARD_BIOS */
242 ENTRY(address_error_trap_handler)
245 mov.l @(r0,r15),r6 ! pc
248 mov #0,r5 ! writeaccess is unknown
251 1: .long do_address_error
256 ldc r0,sr ! all interrupt block (same BL = 1)
257 ! restore special register
258 ! overlap exception frame
271 and r1,r3 ! copy MD bit
273 shll2 r1 ! clear MD bit
275 mov.l @(OFF_SP,r0),r2
277 mov.l r2,@(OFF_SP,r0) ! point exception frame top
278 mov.l r1,@(4,r2) ! set sr
281 mov.l r1,@r2 ! set pc
282 get_current_thread_info r0, r1
283 mov.l $current_thread_info,r1
307 $current_thread_info:
308 .long __current_thread_info
312 ! common exception handler
313 #include "../../entry-common.S"
317 ! bit30 = MD (compatible SH3/4)
322 __current_thread_info:
325 ENTRY(exception_handling_table)