xref: /openbmc/u-boot/arch/arm/lib/vectors.S (revision fea7f3aa) 
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/*
64 *************************************************************************
65 *
66 * Indirect vectors table
67 *
68 * Symbols referenced here must be defined somewhere else
69 *
70 *************************************************************************
71 */
72
73	.globl	_undefined_instruction
74	.globl	_software_interrupt
75	.globl	_prefetch_abort
76	.globl	_data_abort
77	.globl	_not_used
78	.globl	_irq
79	.globl	_fiq
80
81_undefined_instruction:	.word undefined_instruction
82_software_interrupt:	.word software_interrupt
83_prefetch_abort:	.word prefetch_abort
84_data_abort:		.word data_abort
85_not_used:		.word not_used
86_irq:			.word irq
87_fiq:			.word fiq
88
89	.balignl 16,0xdeadbeef
90
91/*
92 *************************************************************************
93 *
94 * Interrupt handling
95 *
96 *************************************************************************
97 */
98
99/* SPL interrupt handling: just hang */
100
101#ifdef CONFIG_SPL_BUILD
102
103	.align	5
104undefined_instruction:
105software_interrupt:
106prefetch_abort:
107data_abort:
108not_used:
109irq:
110fiq:
111
1121:
113	bl	1b			/* hang and never return */
114
115#else	/* !CONFIG_SPL_BUILD */
116
117/* IRQ stack memory (calculated at run-time) + 8 bytes */
118.globl IRQ_STACK_START_IN
119IRQ_STACK_START_IN:
120	.word	0x0badc0de
121
122#ifdef CONFIG_USE_IRQ
123/* IRQ stack memory (calculated at run-time) */
124.globl IRQ_STACK_START
125IRQ_STACK_START:
126	.word	0x0badc0de
127
128/* IRQ stack memory (calculated at run-time) */
129.globl FIQ_STACK_START
130FIQ_STACK_START:
131	.word 0x0badc0de
132
133#endif /* CONFIG_USE_IRQ */
134
135@
136@ IRQ stack frame.
137@
138#define S_FRAME_SIZE	72
139
140#define S_OLD_R0	68
141#define S_PSR		64
142#define S_PC		60
143#define S_LR		56
144#define S_SP		52
145
146#define S_IP		48
147#define S_FP		44
148#define S_R10		40
149#define S_R9		36
150#define S_R8		32
151#define S_R7		28
152#define S_R6		24
153#define S_R5		20
154#define S_R4		16
155#define S_R3		12
156#define S_R2		8
157#define S_R1		4
158#define S_R0		0
159
160#define MODE_SVC 0x13
161#define I_BIT	 0x80
162
163/*
164 * use bad_save_user_regs for abort/prefetch/undef/swi ...
165 * use irq_save_user_regs / irq_restore_user_regs for IRQ/FIQ handling
166 */
167
168	.macro	bad_save_user_regs
169	@ carve out a frame on current user stack
170	sub	sp, sp, #S_FRAME_SIZE
171	stmia	sp, {r0 - r12}	@ Save user registers (now in svc mode) r0-r12
172	ldr	r2, IRQ_STACK_START_IN
173	@ get values for "aborted" pc and cpsr (into parm regs)
174	ldmia	r2, {r2 - r3}
175	add	r0, sp, #S_FRAME_SIZE		@ grab pointer to old stack
176	add	r5, sp, #S_SP
177	mov	r1, lr
178	stmia	r5, {r0 - r3}	@ save sp_SVC, lr_SVC, pc, cpsr
179	mov	r0, sp		@ save current stack into r0 (param register)
180	.endm
181
182	.macro	irq_save_user_regs
183	sub	sp, sp, #S_FRAME_SIZE
184	stmia	sp, {r0 - r12}			@ Calling r0-r12
185	@ !!!! R8 NEEDS to be saved !!!! a reserved stack spot would be good.
186	add	r8, sp, #S_PC
187	stmdb	r8, {sp, lr}^		@ Calling SP, LR
188	str	lr, [r8, #0]		@ Save calling PC
189	mrs	r6, spsr
190	str	r6, [r8, #4]		@ Save CPSR
191	str	r0, [r8, #8]		@ Save OLD_R0
192	mov	r0, sp
193	.endm
194
195	.macro	irq_restore_user_regs
196	ldmia	sp, {r0 - lr}^			@ Calling r0 - lr
197	mov	r0, r0
198	ldr	lr, [sp, #S_PC]			@ Get PC
199	add	sp, sp, #S_FRAME_SIZE
200	subs	pc, lr, #4		@ return & move spsr_svc into cpsr
201	.endm
202
203	.macro get_bad_stack
204	ldr	r13, IRQ_STACK_START_IN		@ setup our mode stack
205
206	str	lr, [r13]	@ save caller lr in position 0 of saved stack
207	mrs	lr, spsr	@ get the spsr
208	str	lr, [r13, #4]	@ save spsr in position 1 of saved stack
209	mov	r13, #MODE_SVC	@ prepare SVC-Mode
210	@ msr	spsr_c, r13
211	msr	spsr, r13	@ switch modes, make sure moves will execute
212	mov	lr, pc		@ capture return pc
213	movs	pc, lr		@ jump to next instruction & switch modes.
214	.endm
215
216	.macro get_irq_stack			@ setup IRQ stack
217	ldr	sp, IRQ_STACK_START
218	.endm
219
220	.macro get_fiq_stack			@ setup FIQ stack
221	ldr	sp, FIQ_STACK_START
222	.endm
223
224/*
225 * exception handlers
226 */
227
228	.align  5
229undefined_instruction:
230	get_bad_stack
231	bad_save_user_regs
232	bl	do_undefined_instruction
233
234	.align	5
235software_interrupt:
236	get_bad_stack
237	bad_save_user_regs
238	bl	do_software_interrupt
239
240	.align	5
241prefetch_abort:
242	get_bad_stack
243	bad_save_user_regs
244	bl	do_prefetch_abort
245
246	.align	5
247data_abort:
248	get_bad_stack
249	bad_save_user_regs
250	bl	do_data_abort
251
252	.align	5
253not_used:
254	get_bad_stack
255	bad_save_user_regs
256	bl	do_not_used
257
258#ifdef CONFIG_USE_IRQ
259
260	.align	5
261irq:
262	get_irq_stack
263	irq_save_user_regs
264	bl	do_irq
265	irq_restore_user_regs
266
267	.align	5
268fiq:
269	get_fiq_stack
270	/* someone ought to write a more effiction fiq_save_user_regs */
271	irq_save_user_regs
272	bl	do_fiq
273	irq_restore_user_regs
274
275#else
276
277	.align	5
278irq:
279	get_bad_stack
280	bad_save_user_regs
281	bl	do_irq
282
283	.align	5
284fiq:
285	get_bad_stack
286	bad_save_user_regs
287	bl	do_fiq
288
289#endif /* CONFIG_USE_IRQ */
290
291#endif	/* CONFIG_SPL_BUILD */
292