xref: /openbmc/u-boot/arch/arm/lib/vectors.S (revision ca6c5e03) 
1/*
2 *  vectors - Generic ARM exception table code
3 *
4 *  Copyright (c) 1998	Dan Malek <dmalek@jlc.net>
5 *  Copyright (c) 1999	Magnus Damm <kieraypc01.p.y.kie.era.ericsson.se>
6 *  Copyright (c) 2000	Wolfgang Denk <wd@denx.de>
7 *  Copyright (c) 2001	Alex Züpke <azu@sysgo.de>
8 *  Copyright (c) 2001	Marius Gröger <mag@sysgo.de>
9 *  Copyright (c) 2002	Alex Züpke <azu@sysgo.de>
10 *  Copyright (c) 2002	Gary Jennejohn <garyj@denx.de>
11 *  Copyright (c) 2002	Kyle Harris <kharris@nexus-tech.net>
12 *
13 * SPDX-License-Identifier:	GPL-2.0+
14 */
15
16#include <config.h>
17
18/*
19 *************************************************************************
20 *
21 * Symbol _start is referenced elsewhere, so make it global
22 *
23 *************************************************************************
24 */
25
26.globl _start
27
28/*
29 *************************************************************************
30 *
31 * Vectors have their own section so linker script can map them easily
32 *
33 *************************************************************************
34 */
35
36	.section ".vectors", "ax"
37
38/*
39 *************************************************************************
40 *
41 * Exception vectors as described in ARM reference manuals
42 *
43 * Uses indirect branch to allow reaching handlers anywhere in memory.
44 *
45 *************************************************************************
46 */
47
48_start:
49
50#ifdef CONFIG_SYS_DV_NOR_BOOT_CFG
51	.word	CONFIG_SYS_DV_NOR_BOOT_CFG
52#endif
53
54	b	reset
55	ldr	pc, _undefined_instruction
56	ldr	pc, _software_interrupt
57	ldr	pc, _prefetch_abort
58	ldr	pc, _data_abort
59	ldr	pc, _not_used
60	ldr	pc, _irq
61	ldr	pc, _fiq
62
63#ifdef CONFIG_ENABLE_ARM_SOC_BOOT0_HOOK
64/*
65 * Various SoCs need something special and SoC-specific up front in
66 * order to boot, allow them to set that in their boot0.h file and then
67 * use it here.
68 */
69#include <asm/arch/boot0.h>
70ARM_SOC_BOOT0_HOOK
71#endif
72
73/*
74 *************************************************************************
75 *
76 * Indirect vectors table
77 *
78 * Symbols referenced here must be defined somewhere else
79 *
80 *************************************************************************
81 */
82
83	.globl	_undefined_instruction
84	.globl	_software_interrupt
85	.globl	_prefetch_abort
86	.globl	_data_abort
87	.globl	_not_used
88	.globl	_irq
89	.globl	_fiq
90
91_undefined_instruction:	.word undefined_instruction
92_software_interrupt:	.word software_interrupt
93_prefetch_abort:	.word prefetch_abort
94_data_abort:		.word data_abort
95_not_used:		.word not_used
96_irq:			.word irq
97_fiq:			.word fiq
98
99	.balignl 16,0xdeadbeef
100
101/*
102 *************************************************************************
103 *
104 * Interrupt handling
105 *
106 *************************************************************************
107 */
108
109/* SPL interrupt handling: just hang */
110
111#ifdef CONFIG_SPL_BUILD
112
113	.align	5
114undefined_instruction:
115software_interrupt:
116prefetch_abort:
117data_abort:
118not_used:
119irq:
120fiq:
121
1221:
123	bl	1b			/* hang and never return */
124
125#else	/* !CONFIG_SPL_BUILD */
126
127/* IRQ stack memory (calculated at run-time) + 8 bytes */
128.globl IRQ_STACK_START_IN
129IRQ_STACK_START_IN:
130	.word	0x0badc0de
131
132#ifdef CONFIG_USE_IRQ
133/* IRQ stack memory (calculated at run-time) */
134.globl IRQ_STACK_START
135IRQ_STACK_START:
136	.word	0x0badc0de
137
138/* IRQ stack memory (calculated at run-time) */
139.globl FIQ_STACK_START
140FIQ_STACK_START:
141	.word 0x0badc0de
142
143#endif /* CONFIG_USE_IRQ */
144
145@
146@ IRQ stack frame.
147@
148#define S_FRAME_SIZE	72
149
150#define S_OLD_R0	68
151#define S_PSR		64
152#define S_PC		60
153#define S_LR		56
154#define S_SP		52
155
156#define S_IP		48
157#define S_FP		44
158#define S_R10		40
159#define S_R9		36
160#define S_R8		32
161#define S_R7		28
162#define S_R6		24
163#define S_R5		20
164#define S_R4		16
165#define S_R3		12
166#define S_R2		8
167#define S_R1		4
168#define S_R0		0
169
170#define MODE_SVC 0x13
171#define I_BIT	 0x80
172
173/*
174 * use bad_save_user_regs for abort/prefetch/undef/swi ...
175 * use irq_save_user_regs / irq_restore_user_regs for IRQ/FIQ handling
176 */
177
178	.macro	bad_save_user_regs
179	@ carve out a frame on current user stack
180	sub	sp, sp, #S_FRAME_SIZE
181	stmia	sp, {r0 - r12}	@ Save user registers (now in svc mode) r0-r12
182	ldr	r2, IRQ_STACK_START_IN
183	@ get values for "aborted" pc and cpsr (into parm regs)
184	ldmia	r2, {r2 - r3}
185	add	r0, sp, #S_FRAME_SIZE		@ grab pointer to old stack
186	add	r5, sp, #S_SP
187	mov	r1, lr
188	stmia	r5, {r0 - r3}	@ save sp_SVC, lr_SVC, pc, cpsr
189	mov	r0, sp		@ save current stack into r0 (param register)
190	.endm
191
192	.macro	irq_save_user_regs
193	sub	sp, sp, #S_FRAME_SIZE
194	stmia	sp, {r0 - r12}			@ Calling r0-r12
195	@ !!!! R8 NEEDS to be saved !!!! a reserved stack spot would be good.
196	add	r8, sp, #S_PC
197	stmdb	r8, {sp, lr}^		@ Calling SP, LR
198	str	lr, [r8, #0]		@ Save calling PC
199	mrs	r6, spsr
200	str	r6, [r8, #4]		@ Save CPSR
201	str	r0, [r8, #8]		@ Save OLD_R0
202	mov	r0, sp
203	.endm
204
205	.macro	irq_restore_user_regs
206	ldmia	sp, {r0 - lr}^			@ Calling r0 - lr
207	mov	r0, r0
208	ldr	lr, [sp, #S_PC]			@ Get PC
209	add	sp, sp, #S_FRAME_SIZE
210	subs	pc, lr, #4		@ return & move spsr_svc into cpsr
211	.endm
212
213	.macro get_bad_stack
214	ldr	r13, IRQ_STACK_START_IN		@ setup our mode stack
215
216	str	lr, [r13]	@ save caller lr in position 0 of saved stack
217	mrs	lr, spsr	@ get the spsr
218	str	lr, [r13, #4]	@ save spsr in position 1 of saved stack
219	mov	r13, #MODE_SVC	@ prepare SVC-Mode
220	@ msr	spsr_c, r13
221	msr	spsr, r13	@ switch modes, make sure moves will execute
222	mov	lr, pc		@ capture return pc
223	movs	pc, lr		@ jump to next instruction & switch modes.
224	.endm
225
226	.macro get_irq_stack			@ setup IRQ stack
227	ldr	sp, IRQ_STACK_START
228	.endm
229
230	.macro get_fiq_stack			@ setup FIQ stack
231	ldr	sp, FIQ_STACK_START
232	.endm
233
234/*
235 * exception handlers
236 */
237
238	.align  5
239undefined_instruction:
240	get_bad_stack
241	bad_save_user_regs
242	bl	do_undefined_instruction
243
244	.align	5
245software_interrupt:
246	get_bad_stack
247	bad_save_user_regs
248	bl	do_software_interrupt
249
250	.align	5
251prefetch_abort:
252	get_bad_stack
253	bad_save_user_regs
254	bl	do_prefetch_abort
255
256	.align	5
257data_abort:
258	get_bad_stack
259	bad_save_user_regs
260	bl	do_data_abort
261
262	.align	5
263not_used:
264	get_bad_stack
265	bad_save_user_regs
266	bl	do_not_used
267
268#ifdef CONFIG_USE_IRQ
269
270	.align	5
271irq:
272	get_irq_stack
273	irq_save_user_regs
274	bl	do_irq
275	irq_restore_user_regs
276
277	.align	5
278fiq:
279	get_fiq_stack
280	/* someone ought to write a more effiction fiq_save_user_regs */
281	irq_save_user_regs
282	bl	do_fiq
283	irq_restore_user_regs
284
285#else
286
287	.align	5
288irq:
289	get_bad_stack
290	bad_save_user_regs
291	bl	do_irq
292
293	.align	5
294fiq:
295	get_bad_stack
296	bad_save_user_regs
297	bl	do_fiq
298
299#endif /* CONFIG_USE_IRQ */
300
301#endif	/* CONFIG_SPL_BUILD */
302