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1 | /* |
2 | * arch/score/kernel/process.c | |
3 | * | |
4 | * Score Processor version. | |
5 | * | |
6 | * Copyright (C) 2009 Sunplus Core Technology Co., Ltd. | |
7 | * Chen Liqin <liqin.chen@sunplusct.com> | |
8 | * Lennox Wu <lennox.wu@sunplusct.com> | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or modify | |
11 | * it under the terms of the GNU General Public License as published by | |
12 | * the Free Software Foundation; either version 2 of the License, or | |
13 | * (at your option) any later version. | |
14 | * | |
15 | * This program is distributed in the hope that it will be useful, | |
16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
18 | * GNU General Public License for more details. | |
19 | * | |
20 | * You should have received a copy of the GNU General Public License | |
21 | * along with this program; if not, see the file COPYING, or write | |
22 | * to the Free Software Foundation, Inc., | |
23 | * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA | |
24 | */ | |
25 | ||
26 | #include <linux/module.h> | |
9fb24cc5 AB |
27 | #include <linux/reboot.h> |
28 | #include <linux/elfcore.h> | |
29 | #include <linux/pm.h> | |
6bc9a396 CL |
30 | |
31 | void (*pm_power_off)(void); | |
32 | EXPORT_SYMBOL(pm_power_off); | |
33 | ||
34 | /* If or when software machine-restart is implemented, add code here. */ | |
35 | void machine_restart(char *command) {} | |
36 | ||
37 | /* If or when software machine-halt is implemented, add code here. */ | |
38 | void machine_halt(void) {} | |
39 | ||
40 | /* If or when software machine-power-off is implemented, add code here. */ | |
41 | void machine_power_off(void) {} | |
42 | ||
43 | /* | |
44 | * The idle thread. There's no useful work to be | |
45 | * done, so just try to conserve power and have a | |
46 | * low exit latency (ie sit in a loop waiting for | |
47 | * somebody to say that they'd like to reschedule) | |
48 | */ | |
49 | void __noreturn cpu_idle(void) | |
50 | { | |
51 | /* endless idle loop with no priority at all */ | |
52 | while (1) { | |
53 | while (!need_resched()) | |
54 | barrier(); | |
55 | ||
56 | preempt_enable_no_resched(); | |
57 | schedule(); | |
58 | preempt_disable(); | |
59 | } | |
60 | } | |
61 | ||
0402c91a | 62 | void ret_from_fork(void); |
6bc9a396 CL |
63 | |
64 | void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp) | |
65 | { | |
66 | unsigned long status; | |
67 | ||
68 | /* New thread loses kernel privileges. */ | |
69 | status = regs->cp0_psr & ~(KU_MASK); | |
70 | status |= KU_USER; | |
71 | regs->cp0_psr = status; | |
72 | regs->cp0_epc = pc; | |
73 | regs->regs[0] = sp; | |
74 | } | |
75 | ||
76 | void exit_thread(void) {} | |
77 | ||
78 | /* | |
79 | * When a process does an "exec", machine state like FPU and debug | |
80 | * registers need to be reset. This is a hook function for that. | |
81 | * Currently we don't have any such state to reset, so this is empty. | |
82 | */ | |
83 | void flush_thread(void) {} | |
84 | ||
85 | /* | |
86 | * set up the kernel stack and exception frames for a new process | |
87 | */ | |
88 | int copy_thread(unsigned long clone_flags, unsigned long usp, | |
89 | unsigned long unused, | |
90 | struct task_struct *p, struct pt_regs *regs) | |
91 | { | |
92 | struct thread_info *ti = task_thread_info(p); | |
93 | struct pt_regs *childregs = task_pt_regs(p); | |
94 | ||
95 | p->set_child_tid = NULL; | |
96 | p->clear_child_tid = NULL; | |
97 | ||
98 | *childregs = *regs; | |
99 | childregs->regs[7] = 0; /* Clear error flag */ | |
100 | childregs->regs[4] = 0; /* Child gets zero as return value */ | |
101 | regs->regs[4] = p->pid; | |
102 | ||
103 | if (childregs->cp0_psr & 0x8) { /* test kernel fork or user fork */ | |
104 | childregs->regs[0] = usp; /* user fork */ | |
105 | } else { | |
106 | childregs->regs[28] = (unsigned long) ti; /* kernel fork */ | |
107 | childregs->regs[0] = (unsigned long) childregs; | |
108 | } | |
109 | ||
110 | p->thread.reg0 = (unsigned long) childregs; | |
111 | p->thread.reg3 = (unsigned long) ret_from_fork; | |
112 | p->thread.cp0_psr = 0; | |
113 | ||
114 | return 0; | |
115 | } | |
116 | ||
117 | /* Fill in the fpu structure for a core dump. */ | |
118 | int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r) | |
119 | { | |
120 | return 1; | |
121 | } | |
122 | ||
123 | static void __noreturn | |
124 | kernel_thread_helper(void *unused0, int (*fn)(void *), | |
125 | void *arg, void *unused1) | |
126 | { | |
127 | do_exit(fn(arg)); | |
128 | } | |
129 | ||
130 | /* | |
131 | * Create a kernel thread. | |
132 | */ | |
133 | long kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) | |
134 | { | |
135 | struct pt_regs regs; | |
136 | ||
137 | memset(®s, 0, sizeof(regs)); | |
138 | ||
139 | regs.regs[6] = (unsigned long) arg; | |
140 | regs.regs[5] = (unsigned long) fn; | |
141 | regs.cp0_epc = (unsigned long) kernel_thread_helper; | |
142 | regs.cp0_psr = (regs.cp0_psr & ~(0x1|0x4|0x8)) | \ | |
143 | ((regs.cp0_psr & 0x3) << 2); | |
144 | ||
145 | return do_fork(flags | CLONE_VM | CLONE_UNTRACED, \ | |
146 | 0, ®s, 0, NULL, NULL); | |
147 | } | |
148 | ||
149 | unsigned long thread_saved_pc(struct task_struct *tsk) | |
150 | { | |
151 | return task_pt_regs(tsk)->cp0_epc; | |
152 | } | |
153 | ||
154 | unsigned long get_wchan(struct task_struct *task) | |
155 | { | |
156 | if (!task || task == current || task->state == TASK_RUNNING) | |
157 | return 0; | |
158 | ||
159 | if (!task_stack_page(task)) | |
160 | return 0; | |
161 | ||
162 | return task_pt_regs(task)->cp0_epc; | |
163 | } | |
164 | ||
165 | unsigned long arch_align_stack(unsigned long sp) | |
166 | { | |
167 | return sp; | |
168 | } |