microblaze: Simplify copy_thread()
[linux-3.10.git] / arch / microblaze / kernel / process.c
1 /*
2  * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
3  * Copyright (C) 2008-2009 PetaLogix
4  * Copyright (C) 2006 Atmark Techno, Inc.
5  *
6  * This file is subject to the terms and conditions of the GNU General Public
7  * License. See the file "COPYING" in the main directory of this archive
8  * for more details.
9  */
10
11 #include <linux/module.h>
12 #include <linux/sched.h>
13 #include <linux/pm.h>
14 #include <linux/tick.h>
15 #include <linux/bitops.h>
16 #include <asm/system.h>
17 #include <asm/pgalloc.h>
18
19 void show_regs(struct pt_regs *regs)
20 {
21         printk(KERN_INFO " Registers dump: mode=%X\r\n", regs->kernel_mode);
22         printk(KERN_INFO " r1=%08lX, r2=%08lX, r3=%08lX, r4=%08lX\n",
23                                 regs->r1, regs->r2, regs->r3, regs->r4);
24         printk(KERN_INFO " r5=%08lX, r6=%08lX, r7=%08lX, r8=%08lX\n",
25                                 regs->r5, regs->r6, regs->r7, regs->r8);
26         printk(KERN_INFO " r9=%08lX, r10=%08lX, r11=%08lX, r12=%08lX\n",
27                                 regs->r9, regs->r10, regs->r11, regs->r12);
28         printk(KERN_INFO " r13=%08lX, r14=%08lX, r15=%08lX, r16=%08lX\n",
29                                 regs->r13, regs->r14, regs->r15, regs->r16);
30         printk(KERN_INFO " r17=%08lX, r18=%08lX, r19=%08lX, r20=%08lX\n",
31                                 regs->r17, regs->r18, regs->r19, regs->r20);
32         printk(KERN_INFO " r21=%08lX, r22=%08lX, r23=%08lX, r24=%08lX\n",
33                                 regs->r21, regs->r22, regs->r23, regs->r24);
34         printk(KERN_INFO " r25=%08lX, r26=%08lX, r27=%08lX, r28=%08lX\n",
35                                 regs->r25, regs->r26, regs->r27, regs->r28);
36         printk(KERN_INFO " r29=%08lX, r30=%08lX, r31=%08lX, rPC=%08lX\n",
37                                 regs->r29, regs->r30, regs->r31, regs->pc);
38         printk(KERN_INFO " msr=%08lX, ear=%08lX, esr=%08lX, fsr=%08lX\n",
39                                 regs->msr, regs->ear, regs->esr, regs->fsr);
40         while (1)
41                 ;
42 }
43
44 void (*pm_idle)(void);
45 void (*pm_power_off)(void) = NULL;
46 EXPORT_SYMBOL(pm_power_off);
47
48 static int hlt_counter = 1;
49
50 void disable_hlt(void)
51 {
52         hlt_counter++;
53 }
54 EXPORT_SYMBOL(disable_hlt);
55
56 void enable_hlt(void)
57 {
58         hlt_counter--;
59 }
60 EXPORT_SYMBOL(enable_hlt);
61
62 static int __init nohlt_setup(char *__unused)
63 {
64         hlt_counter = 1;
65         return 1;
66 }
67 __setup("nohlt", nohlt_setup);
68
69 static int __init hlt_setup(char *__unused)
70 {
71         hlt_counter = 0;
72         return 1;
73 }
74 __setup("hlt", hlt_setup);
75
76 void default_idle(void)
77 {
78         if (!hlt_counter) {
79                 clear_thread_flag(TIF_POLLING_NRFLAG);
80                 smp_mb__after_clear_bit();
81                 local_irq_disable();
82                 while (!need_resched())
83                         cpu_sleep();
84                 local_irq_enable();
85                 set_thread_flag(TIF_POLLING_NRFLAG);
86         } else
87                 while (!need_resched())
88                         cpu_relax();
89 }
90
91 void cpu_idle(void)
92 {
93         set_thread_flag(TIF_POLLING_NRFLAG);
94
95         /* endless idle loop with no priority at all */
96         while (1) {
97                 void (*idle)(void) = pm_idle;
98
99                 if (!idle)
100                         idle = default_idle;
101
102                 tick_nohz_stop_sched_tick(1);
103                 while (!need_resched())
104                         idle();
105                 tick_nohz_restart_sched_tick();
106
107                 preempt_enable_no_resched();
108                 schedule();
109                 preempt_disable();
110                 check_pgt_cache();
111         }
112 }
113
114 void flush_thread(void)
115 {
116 }
117
118 int copy_thread(unsigned long clone_flags, unsigned long usp,
119                 unsigned long unused,
120                 struct task_struct *p, struct pt_regs *regs)
121 {
122         struct pt_regs *childregs = task_pt_regs(p);
123         struct thread_info *ti = task_thread_info(p);
124
125         *childregs = *regs;
126         if (user_mode(regs))
127                 childregs->r1 = usp;
128         else
129                 childregs->r1 = ((unsigned long) ti) + THREAD_SIZE;
130
131         memset(&ti->cpu_context, 0, sizeof(struct cpu_context));
132         ti->cpu_context.r1 = (unsigned long)childregs;
133         ti->cpu_context.msr = (unsigned long)childregs->msr;
134         ti->cpu_context.r15 = (unsigned long)ret_from_fork - 8;
135
136         if (clone_flags & CLONE_SETTLS)
137                 ;
138
139         return 0;
140 }
141
142 /*
143  * Return saved PC of a blocked thread.
144  */
145 unsigned long thread_saved_pc(struct task_struct *tsk)
146 {
147         struct cpu_context *ctx =
148                 &(((struct thread_info *)(tsk->stack))->cpu_context);
149
150         /* Check whether the thread is blocked in resume() */
151         if (in_sched_functions(ctx->r15))
152                 return (unsigned long)ctx->r15;
153         else
154                 return ctx->r14;
155 }
156
157 static void kernel_thread_helper(int (*fn)(void *), void *arg)
158 {
159         fn(arg);
160         do_exit(-1);
161 }
162
163 int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
164 {
165         struct pt_regs regs;
166         int ret;
167
168         memset(&regs, 0, sizeof(regs));
169         /* store them in non-volatile registers */
170         regs.r5 = (unsigned long)fn;
171         regs.r6 = (unsigned long)arg;
172         local_save_flags(regs.msr);
173         regs.pc = (unsigned long)kernel_thread_helper;
174         regs.kernel_mode = 1;
175
176         ret = do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
177                         &regs, 0, NULL, NULL);
178
179         return ret;
180 }
181
182 unsigned long get_wchan(struct task_struct *p)
183 {
184 /* TBD (used by procfs) */
185         return 0;
186 }