aboutsummaryrefslogtreecommitdiff
path: root/arch/arm/kernel/entry-common.S
blob: 55201db0f144418455189f9f7ee8e7cc1cb17fe7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
/*
 *  linux/arch/arm/kernel/entry-common.S
 *
 *  Copyright (C) 2000 Russell King
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/config.h>

#include <asm/thread_info.h>
#include <asm/ptrace.h>
#include <asm/unistd.h>

#include "entry-header.S"


	.align	5
/*
 * This is the fast syscall return path.  We do as little as
 * possible here, and this includes saving r0 back into the SVC
 * stack.
 */
ret_fast_syscall:
	disable_irq				@ disable interrupts
	ldr	r1, [tsk, #TI_FLAGS]
	tst	r1, #_TIF_WORK_MASK
	bne	fast_work_pending
	fast_restore_user_regs

/*
 * Ok, we need to do extra processing, enter the slow path.
 */
fast_work_pending:
	str	r0, [sp, #S_R0+S_OFF]!		@ returned r0
work_pending:
	tst	r1, #_TIF_NEED_RESCHED
	bne	work_resched
	tst	r1, #_TIF_NOTIFY_RESUME | _TIF_SIGPENDING
	beq	no_work_pending
	mov	r0, sp				@ 'regs'
	mov	r2, why				@ 'syscall'
	bl	do_notify_resume
	disable_irq				@ disable interrupts
	b	no_work_pending

work_resched:
	bl	schedule
/*
 * "slow" syscall return path.  "why" tells us if this was a real syscall.
 */
ENTRY(ret_to_user)
ret_slow_syscall:
	disable_irq				@ disable interrupts
	ldr	r1, [tsk, #TI_FLAGS]
	tst	r1, #_TIF_WORK_MASK
	bne	work_pending
no_work_pending:
	slow_restore_user_regs

/*
 * This is how we return from a fork.
 */
ENTRY(ret_from_fork)
	bl	schedule_tail
	get_thread_info tsk
	ldr	r1, [tsk, #TI_FLAGS]		@ check for syscall tracing
	mov	why, #1
	tst	r1, #_TIF_SYSCALL_TRACE		@ are we tracing syscalls?
	beq	ret_slow_syscall
	mov	r1, sp
	mov	r0, #1				@ trace exit [IP = 1]
	bl	syscall_trace
	b	ret_slow_syscall
	

#include "calls.S"

/*=============================================================================
 * SWI handler
 *-----------------------------------------------------------------------------
 */

	/* If we're optimising for StrongARM the resulting code won't 
	   run on an ARM7 and we can save a couple of instructions.  
								--pb */
#ifdef CONFIG_CPU_ARM710
	.macro	arm710_bug_check, instr, temp
	and	\temp, \instr, #0x0f000000	@ check for SWI
	teq	\temp, #0x0f000000
	bne	.Larm700bug
	.endm

.Larm700bug:
	ldr	r0, [sp, #S_PSR]		@ Get calling cpsr
	sub	lr, lr, #4
	str	lr, [r8]
	msr	spsr_cxsf, r0
	ldmia	sp, {r0 - lr}^			@ Get calling r0 - lr
	mov	r0, r0
	ldr	lr, [sp, #S_PC]			@ Get PC
	add	sp, sp, #S_FRAME_SIZE
	movs	pc, lr
#else
	.macro	arm710_bug_check, instr, temp
	.endm
#endif

	.align	5
ENTRY(vector_swi)
	save_user_regs
	zero_fp
	get_scno
	arm710_bug_check scno, ip

#ifdef CONFIG_ALIGNMENT_TRAP
	ldr	ip, __cr_alignment
	ldr	ip, [ip]
	mcr	p15, 0, ip, c1, c0		@ update control register
#endif
	enable_irq

	str	r4, [sp, #-S_OFF]!		@ push fifth arg

	get_thread_info tsk
	ldr	ip, [tsk, #TI_FLAGS]		@ check for syscall tracing
	bic	scno, scno, #0xff000000		@ mask off SWI op-code
	eor	scno, scno, #OS_NUMBER << 20	@ check OS number
	adr	tbl, sys_call_table		@ load syscall table pointer
	tst	ip, #_TIF_SYSCALL_TRACE		@ are we tracing syscalls?
	bne	__sys_trace

	adr	lr, ret_fast_syscall		@ return address
	cmp	scno, #NR_syscalls		@ check upper syscall limit
	ldrcc	pc, [tbl, scno, lsl #2]		@ call sys_* routine

	add	r1, sp, #S_OFF
2:	mov	why, #0				@ no longer a real syscall
	cmp	scno, #ARMSWI_OFFSET
	eor	r0, scno, #OS_NUMBER << 20	@ put OS number back
	bcs	arm_syscall	
	b	sys_ni_syscall			@ not private func

	/*
	 * This is the really slow path.  We're going to be doing
	 * context switches, and waiting for our parent to respond.
	 */
__sys_trace:
	add	r1, sp, #S_OFF
	mov	r0, #0				@ trace entry [IP = 0]
	bl	syscall_trace

	adr	lr, __sys_trace_return		@ return address
	add	r1, sp, #S_R0 + S_OFF		@ pointer to regs
	cmp	scno, #NR_syscalls		@ check upper syscall limit
	ldmccia	r1, {r0 - r3}			@ have to reload r0 - r3
	ldrcc	pc, [tbl, scno, lsl #2]		@ call sys_* routine
	b	2b

__sys_trace_return:
	str	r0, [sp, #S_R0 + S_OFF]!	@ save returned r0
	mov	r1, sp
	mov	r0, #1				@ trace exit [IP = 1]
	bl	syscall_trace
	b	ret_slow_syscall

	.align	5
#ifdef CONFIG_ALIGNMENT_TRAP
	.type	__cr_alignment, #object
__cr_alignment:
	.word	cr_alignment
#endif

	.type	sys_call_table, #object
ENTRY(sys_call_table)
#include "calls.S"

/*============================================================================
 * Special system call wrappers
 */
@ r0 = syscall number
@ r5 = syscall table
		.type	sys_syscall, #function
sys_syscall:
		eor	scno, r0, #OS_NUMBER << 20
		cmp	scno, #__NR_syscall - __NR_SYSCALL_BASE
		cmpne	scno, #NR_syscalls	@ check range
		stmloia	sp, {r5, r6}		@ shuffle args
		movlo	r0, r1
		movlo	r1, r2
		movlo	r2, r3
		movlo	r3, r4
		ldrlo	pc, [tbl, scno, lsl #2]
		b	sys_ni_syscall

sys_fork_wrapper:
		add	r0, sp, #S_OFF
		b	sys_fork

sys_vfork_wrapper:
		add	r0, sp, #S_OFF
		b	sys_vfork

sys_execve_wrapper:
		add	r3, sp, #S_OFF
		b	sys_execve

sys_clone_wrapper:
		add	ip, sp, #S_OFF
		str	ip, [sp, #4]
		b	sys_clone

sys_sigsuspend_wrapper:
		add	r3, sp, #S_OFF
		b	sys_sigsuspend

sys_rt_sigsuspend_wrapper:
		add	r2, sp, #S_OFF
		b	sys_rt_sigsuspend

sys_sigreturn_wrapper:
		add	r0, sp, #S_OFF
		b	sys_sigreturn

sys_rt_sigreturn_wrapper:
		add	r0, sp, #S_OFF
		b	sys_rt_sigreturn

sys_sigaltstack_wrapper:
		ldr	r2, [sp, #S_OFF + S_SP]
		b	do_sigaltstack

sys_futex_wrapper:
		str	r5, [sp, #4]		@ push sixth arg
		b	sys_futex

/*
 * Note: off_4k (r5) is always units of 4K.  If we can't do the requested
 * offset, we return EINVAL.
 */
sys_mmap2:
#if PAGE_SHIFT > 12
		tst	r5, #PGOFF_MASK
		moveq	r5, r5, lsr #PAGE_SHIFT - 12
		streq	r5, [sp, #4]
		beq	do_mmap2
		mov	r0, #-EINVAL
		RETINSTR(mov,pc, lr)
#else
		str	r5, [sp, #4]
		b	do_mmap2
#endif