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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/compiler.h>
14#include <asm/irqflags.h>
15#include <asm/regdef.h>
16#include <asm/mipsregs.h>
17#include <asm/stackframe.h>
18#include <asm/isadep.h>
19#include <asm/thread_info.h>
20
21#ifndef CONFIG_PREEMPTION
22#define resume_kernel restore_all
23#else
24#define __ret_from_irq ret_from_exception
25#endif
26
27 .text
28 .align 5
29#ifndef CONFIG_PREEMPTION
30FEXPORT(ret_from_exception)
31 local_irq_disable # preempt stop
32 b __ret_from_irq
33#endif
34FEXPORT(ret_from_irq)
35 LONG_S s0, TI_REGS($28)
36FEXPORT(__ret_from_irq)
37/*
38 * We can be coming here from a syscall done in the kernel space,
39 * e.g. a failed kernel_execve().
40 */
41resume_userspace_check:
42 LONG_L t0, PT_STATUS(sp) # returning to kernel mode?
43 andi t0, t0, KU_USER
44 beqz t0, resume_kernel
45
46resume_userspace:
47 local_irq_disable # make sure we dont miss an
48 # interrupt setting need_resched
49 # between sampling and return
50 LONG_L a2, TI_FLAGS($28) # current->work
51 andi t0, a2, _TIF_WORK_MASK # (ignoring syscall_trace)
52 bnez t0, work_pending
53 j restore_all
54
55#ifdef CONFIG_PREEMPTION
56resume_kernel:
57 local_irq_disable
58 lw t0, TI_PRE_COUNT($28)
59 bnez t0, restore_all
60 LONG_L t0, TI_FLAGS($28)
61 andi t1, t0, _TIF_NEED_RESCHED
62 beqz t1, restore_all
63 LONG_L t0, PT_STATUS(sp) # Interrupts off?
64 andi t0, 1
65 beqz t0, restore_all
66 PTR_LA ra, restore_all
67 j preempt_schedule_irq
68#endif
69
70FEXPORT(ret_from_kernel_thread)
71 jal schedule_tail # a0 = struct task_struct *prev
72 move a0, s1
73 jal s0
74 j syscall_exit
75
76FEXPORT(ret_from_fork)
77 jal schedule_tail # a0 = struct task_struct *prev
78
79FEXPORT(syscall_exit)
80#ifdef CONFIG_DEBUG_RSEQ
81 move a0, sp
82 jal rseq_syscall
83#endif
84 local_irq_disable # make sure need_resched and
85 # signals dont change between
86 # sampling and return
87 LONG_L a2, TI_FLAGS($28) # current->work
88 li t0, _TIF_ALLWORK_MASK
89 and t0, a2, t0
90 bnez t0, syscall_exit_work
91
92restore_all: # restore full frame
93 .set noat
94 RESTORE_TEMP
95 RESTORE_AT
96 RESTORE_STATIC
97restore_partial: # restore partial frame
98#ifdef CONFIG_TRACE_IRQFLAGS
99 SAVE_STATIC
100 SAVE_AT
101 SAVE_TEMP
102 LONG_L v0, PT_STATUS(sp)
103#if defined(CONFIG_CPU_R3000)
104 and v0, ST0_IEP
105#else
106 and v0, ST0_IE
107#endif
108 beqz v0, 1f
109 jal trace_hardirqs_on
110 b 2f
1111: jal trace_hardirqs_off
1122:
113 RESTORE_TEMP
114 RESTORE_AT
115 RESTORE_STATIC
116#endif
117 RESTORE_SOME
118 RESTORE_SP_AND_RET
119 .set at
120
121work_pending:
122 andi t0, a2, _TIF_NEED_RESCHED # a2 is preloaded with TI_FLAGS
123 beqz t0, work_notifysig
124work_resched:
125 TRACE_IRQS_OFF
126 jal schedule
127
128 local_irq_disable # make sure need_resched and
129 # signals dont change between
130 # sampling and return
131 LONG_L a2, TI_FLAGS($28)
132 andi t0, a2, _TIF_WORK_MASK # is there any work to be done
133 # other than syscall tracing?
134 beqz t0, restore_all
135 andi t0, a2, _TIF_NEED_RESCHED
136 bnez t0, work_resched
137
138work_notifysig: # deal with pending signals and
139 # notify-resume requests
140 move a0, sp
141 li a1, 0
142 jal do_notify_resume # a2 already loaded
143 j resume_userspace_check
144
145FEXPORT(syscall_exit_partial)
146#ifdef CONFIG_DEBUG_RSEQ
147 move a0, sp
148 jal rseq_syscall
149#endif
150 local_irq_disable # make sure need_resched doesn't
151 # change between and return
152 LONG_L a2, TI_FLAGS($28) # current->work
153 li t0, _TIF_ALLWORK_MASK
154 and t0, a2
155 beqz t0, restore_partial
156 SAVE_STATIC
157syscall_exit_work:
158 LONG_L t0, PT_STATUS(sp) # returning to kernel mode?
159 andi t0, t0, KU_USER
160 beqz t0, resume_kernel
161 li t0, _TIF_WORK_SYSCALL_EXIT
162 and t0, a2 # a2 is preloaded with TI_FLAGS
163 beqz t0, work_pending # trace bit set?
164 local_irq_enable # could let syscall_trace_leave()
165 # call schedule() instead
166 TRACE_IRQS_ON
167 move a0, sp
168 jal syscall_trace_leave
169 b resume_userspace
170
171#if defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR5) || \
172 defined(CONFIG_CPU_MIPSR6) || defined(CONFIG_MIPS_MT)
173
174/*
175 * MIPS32R2 Instruction Hazard Barrier - must be called
176 *
177 * For C code use the inline version named instruction_hazard().
178 */
179LEAF(mips_ihb)
180 .set MIPS_ISA_LEVEL_RAW
181 jr.hb ra
182 nop
183 END(mips_ihb)
184
185#endif /* CONFIG_CPU_MIPSR2 - CONFIG_CPU_MIPSR6 or CONFIG_MIPS_MT */