xref: /openbmc/u-boot/arch/arm/lib/vectors.S (revision c4f80f50) 
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/*
17 *************************************************************************
18 *
19 * Symbol _start is referenced elsewhere, so make it global
20 *
21 *************************************************************************
22 */
23
24.globl _start
25
26/*
27 *************************************************************************
28 *
29 * Vectors have their own section so linker script can map them easily
30 *
31 *************************************************************************
32 */
33
34	.section ".vectors", "x"
35
36/*
37 *************************************************************************
38 *
39 * Exception vectors as described in ARM reference manuals
40 *
41 * Uses indirect branch to allow reaching handlers anywhere in memory.
42 *
43 *************************************************************************
44 */
45
46#ifdef CONFIG_SYS_DV_NOR_BOOT_CFG
47	.word	CONFIG_SYS_DV_NOR_BOOT_CFG
48#endif
49
50_start:
51	ldr	pc, _reset
52	ldr	pc, _undefined_instruction
53	ldr	pc, _software_interrupt
54	ldr	pc, _prefetch_abort
55	ldr	pc, _data_abort
56	ldr	pc, _not_used
57	ldr	pc, _irq
58	ldr	pc, _fiq
59
60/*
61 *************************************************************************
62 *
63 * Indirect vectors table
64 *
65 * Symbols referenced here must be defined somewhere else
66 *
67 *************************************************************************
68 */
69
70	.globl	_undefined_instruction
71	.globl	_software_interrupt
72	.globl	_prefetch_abort
73	.globl	_data_abort
74	.globl	_not_used
75	.globl	_irq
76	.globl	_fiq
77
78_reset:			.word reset
79_undefined_instruction:	.word undefined_instruction
80_software_interrupt:	.word software_interrupt
81_prefetch_abort:	.word prefetch_abort
82_data_abort:		.word data_abort
83_not_used:		.word not_used
84_irq:			.word irq
85_fiq:			.word fiq
86
87	.balignl 16,0xdeadbeef
88
89/*
90 *************************************************************************
91 *
92 * Interrupt handling
93 *
94 *************************************************************************
95 */
96
97/* SPL interrupt handling: just hang */
98
99#ifdef CONFIG_SPL_BUILD
100
101	.align	5
102undefined_instruction:
103software_interrupt:
104prefetch_abort:
105data_abort:
106not_used:
107irq:
108fiq:
109
1101:
111	bl	1b			/* hang and never return */
112
113#else	/* !CONFIG_SPL_BUILD */
114
115/* IRQ stack memory (calculated at run-time) + 8 bytes */
116.globl IRQ_STACK_START_IN
117IRQ_STACK_START_IN:
118	.word	0x0badc0de
119
120#ifdef CONFIG_USE_IRQ
121/* IRQ stack memory (calculated at run-time) */
122.globl IRQ_STACK_START
123IRQ_STACK_START:
124	.word	0x0badc0de
125
126/* IRQ stack memory (calculated at run-time) */
127.globl FIQ_STACK_START
128FIQ_STACK_START:
129	.word 0x0badc0de
130
131#endif /* CONFIG_USE_IRQ */
132
133@
134@ IRQ stack frame.
135@
136#define S_FRAME_SIZE	72
137
138#define S_OLD_R0	68
139#define S_PSR		64
140#define S_PC		60
141#define S_LR		56
142#define S_SP		52
143
144#define S_IP		48
145#define S_FP		44
146#define S_R10		40
147#define S_R9		36
148#define S_R8		32
149#define S_R7		28
150#define S_R6		24
151#define S_R5		20
152#define S_R4		16
153#define S_R3		12
154#define S_R2		8
155#define S_R1		4
156#define S_R0		0
157
158#define MODE_SVC 0x13
159#define I_BIT	 0x80
160
161/*
162 * use bad_save_user_regs for abort/prefetch/undef/swi ...
163 * use irq_save_user_regs / irq_restore_user_regs for IRQ/FIQ handling
164 */
165
166	.macro	bad_save_user_regs
167	@ carve out a frame on current user stack
168	sub	sp, sp, #S_FRAME_SIZE
169	stmia	sp, {r0 - r12}	@ Save user registers (now in svc mode) r0-r12
170	ldr	r2, IRQ_STACK_START_IN
171	@ get values for "aborted" pc and cpsr (into parm regs)
172	ldmia	r2, {r2 - r3}
173	add	r0, sp, #S_FRAME_SIZE		@ grab pointer to old stack
174	add	r5, sp, #S_SP
175	mov	r1, lr
176	stmia	r5, {r0 - r3}	@ save sp_SVC, lr_SVC, pc, cpsr
177	mov	r0, sp		@ save current stack into r0 (param register)
178	.endm
179
180	.macro	irq_save_user_regs
181	sub	sp, sp, #S_FRAME_SIZE
182	stmia	sp, {r0 - r12}			@ Calling r0-r12
183	@ !!!! R8 NEEDS to be saved !!!! a reserved stack spot would be good.
184	add	r8, sp, #S_PC
185	stmdb	r8, {sp, lr}^		@ Calling SP, LR
186	str	lr, [r8, #0]		@ Save calling PC
187	mrs	r6, spsr
188	str	r6, [r8, #4]		@ Save CPSR
189	str	r0, [r8, #8]		@ Save OLD_R0
190	mov	r0, sp
191	.endm
192
193	.macro	irq_restore_user_regs
194	ldmia	sp, {r0 - lr}^			@ Calling r0 - lr
195	mov	r0, r0
196	ldr	lr, [sp, #S_PC]			@ Get PC
197	add	sp, sp, #S_FRAME_SIZE
198	subs	pc, lr, #4		@ return & move spsr_svc into cpsr
199	.endm
200
201	.macro get_bad_stack
202	ldr	r13, IRQ_STACK_START_IN		@ setup our mode stack
203
204	str	lr, [r13]	@ save caller lr in position 0 of saved stack
205	mrs	lr, spsr	@ get the spsr
206	str	lr, [r13, #4]	@ save spsr in position 1 of saved stack
207	mov	r13, #MODE_SVC	@ prepare SVC-Mode
208	@ msr	spsr_c, r13
209	msr	spsr, r13	@ switch modes, make sure moves will execute
210	mov	lr, pc		@ capture return pc
211	movs	pc, lr		@ jump to next instruction & switch modes.
212	.endm
213
214	.macro get_irq_stack			@ setup IRQ stack
215	ldr	sp, IRQ_STACK_START
216	.endm
217
218	.macro get_fiq_stack			@ setup FIQ stack
219	ldr	sp, FIQ_STACK_START
220	.endm
221
222/*
223 * exception handlers
224 */
225
226	.align  5
227undefined_instruction:
228	get_bad_stack
229	bad_save_user_regs
230	bl	do_undefined_instruction
231
232	.align	5
233software_interrupt:
234	get_bad_stack
235	bad_save_user_regs
236	bl	do_software_interrupt
237
238	.align	5
239prefetch_abort:
240	get_bad_stack
241	bad_save_user_regs
242	bl	do_prefetch_abort
243
244	.align	5
245data_abort:
246	get_bad_stack
247	bad_save_user_regs
248	bl	do_data_abort
249
250	.align	5
251not_used:
252	get_bad_stack
253	bad_save_user_regs
254	bl	do_not_used
255
256#ifdef CONFIG_USE_IRQ
257
258	.align	5
259irq:
260	get_irq_stack
261	irq_save_user_regs
262	bl	do_irq
263	irq_restore_user_regs
264
265	.align	5
266fiq:
267	get_fiq_stack
268	/* someone ought to write a more effiction fiq_save_user_regs */
269	irq_save_user_regs
270	bl	do_fiq
271	irq_restore_user_regs
272
273#else
274
275	.align	5
276irq:
277	get_bad_stack
278	bad_save_user_regs
279	bl	do_irq
280
281	.align	5
282fiq:
283	get_bad_stack
284	bad_save_user_regs
285	bl	do_fiq
286
287#endif /* CONFIG_USE_IRQ */
288
289#endif	/* CONFIG_SPL_BUILD */
290