1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License.  See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 1994 - 2000, 2001, 2003 Ralf Baechle
7 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
8 * Copyright (C) 2001 MIPS Technologies, Inc.
9 */
10
11#include <asm/asm.h>
12#include <asm/asmmacro.h>
13#include <asm/regdef.h>
14#include <asm/mipsregs.h>
15#include <asm/stackframe.h>
16#include <asm/isadep.h>
17#include <asm/thread_info.h>
18#include <asm/war.h>
19#ifdef CONFIG_MIPS_MT_SMTC
20#include <asm/mipsmtregs.h>
21#endif
22
23#ifndef CONFIG_PREEMPT
24#define resume_kernel	restore_all
25#else
26#define __ret_from_irq	ret_from_exception
27#endif
28
29	.text
30	.align	5
31#ifndef CONFIG_PREEMPT
32FEXPORT(ret_from_exception)
33	local_irq_disable			# preempt stop
34	b	__ret_from_irq
35#endif
36FEXPORT(ret_from_irq)
37	LONG_S	s0, TI_REGS($28)
38FEXPORT(__ret_from_irq)
39	LONG_L	t0, PT_STATUS(sp)		# returning to kernel mode?
40	andi	t0, t0, KU_USER
41	beqz	t0, resume_kernel
42
43resume_userspace:
44	local_irq_disable		# make sure we dont miss an
45					# interrupt setting need_resched
46					# between sampling and return
47	LONG_L	a2, TI_FLAGS($28)	# current->work
48	andi	t0, a2, _TIF_WORK_MASK	# (ignoring syscall_trace)
49	bnez	t0, work_pending
50	j	restore_all
51
52#ifdef CONFIG_PREEMPT
53resume_kernel:
54	local_irq_disable
55	lw	t0, TI_PRE_COUNT($28)
56	bnez	t0, restore_all
57need_resched:
58	LONG_L	t0, TI_FLAGS($28)
59	andi	t1, t0, _TIF_NEED_RESCHED
60	beqz	t1, restore_all
61	LONG_L	t0, PT_STATUS(sp)		# Interrupts off?
62	andi	t0, 1
63	beqz	t0, restore_all
64	jal	preempt_schedule_irq
65	b	need_resched
66#endif
67
68FEXPORT(ret_from_fork)
69	jal	schedule_tail		# a0 = struct task_struct *prev
70
71FEXPORT(syscall_exit)
72	local_irq_disable		# make sure need_resched and
73					# signals dont change between
74					# sampling and return
75	LONG_L	a2, TI_FLAGS($28)	# current->work
76	li	t0, _TIF_ALLWORK_MASK
77	and	t0, a2, t0
78	bnez	t0, syscall_exit_work
79
80FEXPORT(restore_all)			# restore full frame
81#ifdef CONFIG_MIPS_MT_SMTC
82#ifdef CONFIG_MIPS_MT_SMTC_IM_BACKSTOP
83/* Re-arm any temporarily masked interrupts not explicitly "acked" */
84	mfc0	v0, CP0_TCSTATUS
85	ori	v1, v0, TCSTATUS_IXMT
86	mtc0	v1, CP0_TCSTATUS
87	andi	v0, TCSTATUS_IXMT
88	_ehb
89	mfc0	t0, CP0_TCCONTEXT
90	DMT	9				# dmt t1
91	jal	mips_ihb
92	mfc0	t2, CP0_STATUS
93	andi	t3, t0, 0xff00
94	or	t2, t2, t3
95	mtc0	t2, CP0_STATUS
96	_ehb
97	andi	t1, t1, VPECONTROL_TE
98	beqz	t1, 1f
99	EMT
1001:
101	mfc0	v1, CP0_TCSTATUS
102	/* We set IXMT above, XOR should clear it here */
103	xori	v1, v1, TCSTATUS_IXMT
104	or	v1, v0, v1
105	mtc0	v1, CP0_TCSTATUS
106	_ehb
107	xor	t0, t0, t3
108	mtc0	t0, CP0_TCCONTEXT
109#endif /* CONFIG_MIPS_MT_SMTC_IM_BACKSTOP */
110/* Detect and execute deferred IPI "interrupts" */
111	LONG_L	s0, TI_REGS($28)
112	LONG_S	sp, TI_REGS($28)
113	jal	deferred_smtc_ipi
114	LONG_S	s0, TI_REGS($28)
115#endif /* CONFIG_MIPS_MT_SMTC */
116	.set	noat
117	RESTORE_TEMP
118	RESTORE_AT
119	RESTORE_STATIC
120FEXPORT(restore_partial)		# restore partial frame
121#ifdef CONFIG_TRACE_IRQFLAGS
122	SAVE_STATIC
123	SAVE_AT
124	SAVE_TEMP
125	LONG_L	v0, PT_STATUS(sp)
126#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
127	and	v0, ST0_IEP
128#else
129	and	v0, ST0_IE
130#endif
131	beqz	v0, 1f
132	jal	trace_hardirqs_on
133	b	2f
1341:	jal	trace_hardirqs_off
1352:
136	RESTORE_TEMP
137	RESTORE_AT
138	RESTORE_STATIC
139#endif
140	RESTORE_SOME
141	RESTORE_SP_AND_RET
142	.set	at
143
144work_pending:
145	andi	t0, a2, _TIF_NEED_RESCHED # a2 is preloaded with TI_FLAGS
146	beqz	t0, work_notifysig
147work_resched:
148	jal	schedule
149
150	local_irq_disable		# make sure need_resched and
151					# signals dont change between
152					# sampling and return
153	LONG_L	a2, TI_FLAGS($28)
154	andi	t0, a2, _TIF_WORK_MASK	# is there any work to be done
155					# other than syscall tracing?
156	beqz	t0, restore_all
157	andi	t0, a2, _TIF_NEED_RESCHED
158	bnez	t0, work_resched
159
160work_notifysig:				# deal with pending signals and
161					# notify-resume requests
162	move	a0, sp
163	li	a1, 0
164	jal	do_notify_resume	# a2 already loaded
165	j	resume_userspace
166
167FEXPORT(syscall_exit_work_partial)
168	SAVE_STATIC
169syscall_exit_work:
170	li	t0, _TIF_WORK_SYSCALL_EXIT
171	and	t0, a2			# a2 is preloaded with TI_FLAGS
172	beqz	t0, work_pending	# trace bit set?
173	local_irq_enable		# could let syscall_trace_leave()
174					# call schedule() instead
175	move	a0, sp
176	jal	syscall_trace_leave
177	b	resume_userspace
178
179#if defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_MIPS_MT)
180
181/*
182 * MIPS32R2 Instruction Hazard Barrier - must be called
183 *
184 * For C code use the inline version named instruction_hazard().
185 */
186LEAF(mips_ihb)
187	.set	mips32r2
188	jr.hb	ra
189	nop
190	END(mips_ihb)
191
192#endif /* CONFIG_CPU_MIPSR2 or CONFIG_MIPS_MT */
193