nohz: Allow rcu extended quiescent state handling seperately from tick stop
[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 #include <asm/uaccess.h> /* for USER_DS macros */
19 #include <asm/cacheflush.h>
20
21 void show_regs(struct pt_regs *regs)
22 {
23         printk(KERN_INFO " Registers dump: mode=%X\r\n", regs->pt_mode);
24         printk(KERN_INFO " r1=%08lX, r2=%08lX, r3=%08lX, r4=%08lX\n",
25                                 regs->r1, regs->r2, regs->r3, regs->r4);
26         printk(KERN_INFO " r5=%08lX, r6=%08lX, r7=%08lX, r8=%08lX\n",
27                                 regs->r5, regs->r6, regs->r7, regs->r8);
28         printk(KERN_INFO " r9=%08lX, r10=%08lX, r11=%08lX, r12=%08lX\n",
29                                 regs->r9, regs->r10, regs->r11, regs->r12);
30         printk(KERN_INFO " r13=%08lX, r14=%08lX, r15=%08lX, r16=%08lX\n",
31                                 regs->r13, regs->r14, regs->r15, regs->r16);
32         printk(KERN_INFO " r17=%08lX, r18=%08lX, r19=%08lX, r20=%08lX\n",
33                                 regs->r17, regs->r18, regs->r19, regs->r20);
34         printk(KERN_INFO " r21=%08lX, r22=%08lX, r23=%08lX, r24=%08lX\n",
35                                 regs->r21, regs->r22, regs->r23, regs->r24);
36         printk(KERN_INFO " r25=%08lX, r26=%08lX, r27=%08lX, r28=%08lX\n",
37                                 regs->r25, regs->r26, regs->r27, regs->r28);
38         printk(KERN_INFO " r29=%08lX, r30=%08lX, r31=%08lX, rPC=%08lX\n",
39                                 regs->r29, regs->r30, regs->r31, regs->pc);
40         printk(KERN_INFO " msr=%08lX, ear=%08lX, esr=%08lX, fsr=%08lX\n",
41                                 regs->msr, regs->ear, regs->esr, regs->fsr);
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 (likely(hlt_counter)) {
79                 local_irq_disable();
80                 stop_critical_timings();
81                 cpu_relax();
82                 start_critical_timings();
83                 local_irq_enable();
84         } else {
85                 clear_thread_flag(TIF_POLLING_NRFLAG);
86                 smp_mb__after_clear_bit();
87                 local_irq_disable();
88                 while (!need_resched())
89                         cpu_sleep();
90                 local_irq_enable();
91                 set_thread_flag(TIF_POLLING_NRFLAG);
92         }
93 }
94
95 void cpu_idle(void)
96 {
97         set_thread_flag(TIF_POLLING_NRFLAG);
98
99         /* endless idle loop with no priority at all */
100         while (1) {
101                 void (*idle)(void) = pm_idle;
102
103                 if (!idle)
104                         idle = default_idle;
105
106                 tick_nohz_idle_enter_norcu();
107                 while (!need_resched())
108                         idle();
109                 tick_nohz_idle_exit_norcu();
110
111                 preempt_enable_no_resched();
112                 schedule();
113                 preempt_disable();
114                 check_pgt_cache();
115         }
116 }
117
118 void flush_thread(void)
119 {
120 }
121
122 int copy_thread(unsigned long clone_flags, unsigned long usp,
123                 unsigned long unused,
124                 struct task_struct *p, struct pt_regs *regs)
125 {
126         struct pt_regs *childregs = task_pt_regs(p);
127         struct thread_info *ti = task_thread_info(p);
128
129         *childregs = *regs;
130         if (user_mode(regs))
131                 childregs->r1 = usp;
132         else
133                 childregs->r1 = ((unsigned long) ti) + THREAD_SIZE;
134
135 #ifndef CONFIG_MMU
136         memset(&ti->cpu_context, 0, sizeof(struct cpu_context));
137         ti->cpu_context.r1 = (unsigned long)childregs;
138         ti->cpu_context.msr = (unsigned long)childregs->msr;
139 #else
140
141         /* if creating a kernel thread then update the current reg (we don't
142          * want to use the parent's value when restoring by POP_STATE) */
143         if (kernel_mode(regs))
144                 /* save new current on stack to use POP_STATE */
145                 childregs->CURRENT_TASK = (unsigned long)p;
146         /* if returning to user then use the parent's value of this register */
147
148         /* if we're creating a new kernel thread then just zeroing all
149          * the registers. That's OK for a brand new thread.*/
150         /* Pls. note that some of them will be restored in POP_STATE */
151         if (kernel_mode(regs))
152                 memset(&ti->cpu_context, 0, sizeof(struct cpu_context));
153         /* if this thread is created for fork/vfork/clone, then we want to
154          * restore all the parent's context */
155         /* in addition to the registers which will be restored by POP_STATE */
156         else {
157                 ti->cpu_context = *(struct cpu_context *)regs;
158                 childregs->msr |= MSR_UMS;
159         }
160
161         /* FIXME STATE_SAVE_PT_OFFSET; */
162         ti->cpu_context.r1  = (unsigned long)childregs;
163         /* we should consider the fact that childregs is a copy of the parent
164          * regs which were saved immediately after entering the kernel state
165          * before enabling VM. This MSR will be restored in switch_to and
166          * RETURN() and we want to have the right machine state there
167          * specifically this state must have INTs disabled before and enabled
168          * after performing rtbd
169          * compose the right MSR for RETURN(). It will work for switch_to also
170          * excepting for VM and UMS
171          * don't touch UMS , CARRY and cache bits
172          * right now MSR is a copy of parent one */
173         childregs->msr |= MSR_BIP;
174         childregs->msr &= ~MSR_EIP;
175         childregs->msr |= MSR_IE;
176         childregs->msr &= ~MSR_VM;
177         childregs->msr |= MSR_VMS;
178         childregs->msr |= MSR_EE; /* exceptions will be enabled*/
179
180         ti->cpu_context.msr = (childregs->msr|MSR_VM);
181         ti->cpu_context.msr &= ~MSR_UMS; /* switch_to to kernel mode */
182         ti->cpu_context.msr &= ~MSR_IE;
183 #endif
184         ti->cpu_context.r15 = (unsigned long)ret_from_fork - 8;
185
186         if (clone_flags & CLONE_SETTLS)
187                 ;
188
189         return 0;
190 }
191
192 #ifndef CONFIG_MMU
193 /*
194  * Return saved PC of a blocked thread.
195  */
196 unsigned long thread_saved_pc(struct task_struct *tsk)
197 {
198         struct cpu_context *ctx =
199                 &(((struct thread_info *)(tsk->stack))->cpu_context);
200
201         /* Check whether the thread is blocked in resume() */
202         if (in_sched_functions(ctx->r15))
203                 return (unsigned long)ctx->r15;
204         else
205                 return ctx->r14;
206 }
207 #endif
208
209 static void kernel_thread_helper(int (*fn)(void *), void *arg)
210 {
211         fn(arg);
212         do_exit(-1);
213 }
214
215 int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
216 {
217         struct pt_regs regs;
218
219         memset(&regs, 0, sizeof(regs));
220         /* store them in non-volatile registers */
221         regs.r5 = (unsigned long)fn;
222         regs.r6 = (unsigned long)arg;
223         local_save_flags(regs.msr);
224         regs.pc = (unsigned long)kernel_thread_helper;
225         regs.pt_mode = 1;
226
227         return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
228                         &regs, 0, NULL, NULL);
229 }
230 EXPORT_SYMBOL_GPL(kernel_thread);
231
232 unsigned long get_wchan(struct task_struct *p)
233 {
234 /* TBD (used by procfs) */
235         return 0;
236 }
237
238 /* Set up a thread for executing a new program */
239 void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long usp)
240 {
241         regs->pc = pc;
242         regs->r1 = usp;
243         regs->pt_mode = 0;
244 #ifdef CONFIG_MMU
245         regs->msr |= MSR_UMS;
246 #endif
247 }
248
249 #ifdef CONFIG_MMU
250 #include <linux/elfcore.h>
251 /*
252  * Set up a thread for executing a new program
253  */
254 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpregs)
255 {
256         return 0; /* MicroBlaze has no separate FPU registers */
257 }
258 #endif /* CONFIG_MMU */