1/* SPDX-License-Identifier: GPL-2.0-or-later
  2 *
  3 *  entry.S  -- interrupt and exception processing for ColdFire
  4 *
  5 *  Copyright (C) 1999-2007, Greg Ungerer (gerg@snapgear.com)
  6 *  Copyright (C) 1998  D. Jeff Dionne <jeff@lineo.ca>,
  7 *                      Kenneth Albanowski <kjahds@kjahds.com>,
  8 *  Copyright (C) 2000  Lineo Inc. (www.lineo.com)
  9 *  Copyright (C) 2004-2006  Macq Electronique SA. (www.macqel.com)
 10 *
 11 * Based on:
 12 *
 13 *  linux/arch/m68k/kernel/entry.S
 14 *
 15 *  Copyright (C) 1991, 1992  Linus Torvalds
 16 *
 17 * Linux/m68k support by Hamish Macdonald
 18 *
 19 * 68060 fixes by Jesper Skov
 20 * ColdFire support by Greg Ungerer (gerg@snapgear.com)
 21 * 5307 fixes by David W. Miller
 22 * linux 2.4 support David McCullough <davidm@snapgear.com>
 23 * Bug, speed and maintainability fixes by Philippe De Muyter <phdm@macqel.be>
 24 */
 25
 26#include <linux/linkage.h>
 27#include <asm/unistd.h>
 28#include <asm/thread_info.h>
 29#include <asm/errno.h>
 30#include <asm/setup.h>
 31#include <asm/asm-offsets.h>
 32#include <asm/entry.h>
 33
 34#ifdef CONFIG_COLDFIRE_SW_A7
 35/*
 36 *	Define software copies of the supervisor and user stack pointers.
 37 */
 38.bss
 39sw_ksp:
 40.long	0
 41sw_usp:
 42.long	0
 43#endif /* CONFIG_COLDFIRE_SW_A7 */
 44
 45.text
 46
 47.globl system_call
 48.globl resume
 49.globl ret_from_exception
 50.globl sys_call_table
 51.globl inthandler
 52
 53enosys:
 54	mov.l	#sys_ni_syscall,%d3
 55	bra	1f
 56
 57ENTRY(system_call)
 58	SAVE_ALL_SYS
 59	move	#0x2000,%sr		/* enable intrs again */
 60	GET_CURRENT(%d2)
 61
 62	cmpl	#NR_syscalls,%d0
 63	jcc	enosys
 64	lea	sys_call_table,%a0
 65	lsll	#2,%d0			/* movel %a0@(%d0:l:4),%d3 */
 66	movel	%a0@(%d0),%d3
 67	jeq	enosys
 68
 691:
 70	movel	%sp,%d2			/* get thread_info pointer */
 71	andl	#-THREAD_SIZE,%d2	/* at start of kernel stack */
 72	movel	%d2,%a0
 73	movel	%a0@,%a1		/* save top of frame */
 74	movel	%sp,%a1@(TASK_THREAD+THREAD_ESP0)
 75	btst	#(TIF_SYSCALL_TRACE%8),%a0@(TINFO_FLAGS+(31-TIF_SYSCALL_TRACE)/8)
 76	bnes	1f
 77
 78	movel	%d3,%a0
 79	jbsr	%a0@
 80	movel	%d0,%sp@(PT_OFF_D0)	/* save the return value */
 81	jra	ret_from_exception
 821:
 83	movel	#-ENOSYS,%d2		/* strace needs -ENOSYS in PT_OFF_D0 */
 84	movel	%d2,PT_OFF_D0(%sp)	/* on syscall entry */
 85	subql	#4,%sp
 86	SAVE_SWITCH_STACK
 87	jbsr	syscall_trace_enter
 88	RESTORE_SWITCH_STACK
 89	addql	#4,%sp
 90	addql	#1,%d0
 91	jeq	ret_from_exception
 92	movel	%d3,%a0
 93	jbsr	%a0@
 94	movel	%d0,%sp@(PT_OFF_D0)		/* save the return value */
 95	subql	#4,%sp			/* dummy return address */
 96	SAVE_SWITCH_STACK
 97	jbsr	syscall_trace_leave
 98	RESTORE_SWITCH_STACK
 99	addql	#4,%sp
100
101ret_from_exception:
102	move	#0x2700,%sr		/* disable intrs */
103	btst	#5,%sp@(PT_OFF_SR)	/* check if returning to kernel */
104	jeq	Luser_return		/* if so, skip resched, signals */
105
106#ifdef CONFIG_PREEMPTION
107	movel	%sp,%d1			/* get thread_info pointer */
108	andl	#-THREAD_SIZE,%d1	/* at base of kernel stack */
109	movel	%d1,%a0
110	movel	%a0@(TINFO_FLAGS),%d1	/* get thread_info->flags */
111	andl	#(1<<TIF_NEED_RESCHED),%d1
112	jeq	Lkernel_return
113
114	movel	%a0@(TINFO_PREEMPT),%d1
115	cmpl	#0,%d1
116	jne	Lkernel_return
117
118	pea	Lkernel_return
119	jmp	preempt_schedule_irq	/* preempt the kernel */
120#endif
121
122Lkernel_return:
123	moveml	%sp@,%d1-%d5/%a0-%a2
124	lea	%sp@(32),%sp		/* space for 8 regs */
125	movel	%sp@+,%d0
126	addql	#4,%sp			/* orig d0 */
127	addl	%sp@+,%sp		/* stk adj */
128	rte
129
130Luser_return:
131	movel	%sp,%d1			/* get thread_info pointer */
132	andl	#-THREAD_SIZE,%d1	/* at base of kernel stack */
133	movel	%d1,%a0
134	moveb	%a0@(TINFO_FLAGS+3),%d1	/* thread_info->flags (low 8 bits) */
135	jne	Lwork_to_do		/* still work to do */
136
137Lreturn:
138	RESTORE_USER
139
140Lwork_to_do:
141	movel	%a0@(TINFO_FLAGS),%d1	/* get thread_info->flags */
142	move	#0x2000,%sr		/* enable intrs again */
143	btst	#TIF_NEED_RESCHED,%d1
144	jne	reschedule
145
146Lsignal_return:
147	subql	#4,%sp			/* dummy return address */
148	SAVE_SWITCH_STACK
149	pea	%sp@(SWITCH_STACK_SIZE)
150	jsr	do_notify_resume
151	addql	#4,%sp
152	RESTORE_SWITCH_STACK
153	addql	#4,%sp
154	jmp	Luser_return
155
156/*
157 * This is the generic interrupt handler (for all hardware interrupt
158 * sources). Calls up to high level code to do all the work.
159 */
160ENTRY(inthandler)
161	SAVE_ALL_INT
162	GET_CURRENT(%d2)
163
164	movew	%sp@(PT_OFF_FORMATVEC),%d0 /* put exception # in d0 */
165	andl	#0x03fc,%d0		/* mask out vector only */
166
167	movel	%sp,%sp@-		/* push regs arg */
168	lsrl	#2,%d0			/* calculate real vector # */
169	movel	%d0,%sp@-		/* push vector number */
170	jbsr	do_IRQ			/* call high level irq handler */
171	lea	%sp@(8),%sp		/* pop args off stack */
172
173	bra	ret_from_exception
174
175/*
176 * Beware - when entering resume, prev (the current task) is
177 * in a0, next (the new task) is in a1, so don't change these
178 * registers until their contents are no longer needed.
179 */
180ENTRY(resume)
181	movew	%sr,%d1				 /* save current status */
182	movew	%d1,%a0@(TASK_THREAD+THREAD_SR)
183	movel	%a0,%d1				 /* get prev thread in d1 */
184	SAVE_SWITCH_STACK
185	movel	%sp,%a0@(TASK_THREAD+THREAD_KSP) /* save kernel stack pointer */
186	RDUSP					 /* movel %usp,%a3 */
187	movel	%a3,%a0@(TASK_THREAD+THREAD_USP) /* save thread user stack */
188#ifdef CONFIG_MMU
189	movel	%a1,%a2				 /* set new current */
190#endif
191	movel	%a1@(TASK_THREAD+THREAD_USP),%a3 /* restore thread user stack */
192	WRUSP					 /* movel %a3,%usp */
193	movel	%a1@(TASK_THREAD+THREAD_KSP),%sp /* restore new kernel stack */
194	movew	%a1@(TASK_THREAD+THREAD_SR),%d7	 /* restore new status */
195	movew	%d7,%sr
196	RESTORE_SWITCH_STACK
197	rts
198