microblaze_mmu_v2: Update process creation for MMU
[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->pt_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 }
41
42 void (*pm_idle)(void);
43 void (*pm_power_off)(void) = NULL;
44 EXPORT_SYMBOL(pm_power_off);
45
46 static int hlt_counter = 1;
47
48 void disable_hlt(void)
49 {
50         hlt_counter++;
51 }
52 EXPORT_SYMBOL(disable_hlt);
53
54 void enable_hlt(void)
55 {
56         hlt_counter--;
57 }
58 EXPORT_SYMBOL(enable_hlt);
59
60 static int __init nohlt_setup(char *__unused)
61 {
62         hlt_counter = 1;
63         return 1;
64 }
65 __setup("nohlt", nohlt_setup);
66
67 static int __init hlt_setup(char *__unused)
68 {
69         hlt_counter = 0;
70         return 1;
71 }
72 __setup("hlt", hlt_setup);
73
74 void default_idle(void)
75 {
76         if (!hlt_counter) {
77                 clear_thread_flag(TIF_POLLING_NRFLAG);
78                 smp_mb__after_clear_bit();
79                 local_irq_disable();
80                 while (!need_resched())
81                         cpu_sleep();
82                 local_irq_enable();
83                 set_thread_flag(TIF_POLLING_NRFLAG);
84         } else
85                 while (!need_resched())
86                         cpu_relax();
87 }
88
89 void cpu_idle(void)
90 {
91         set_thread_flag(TIF_POLLING_NRFLAG);
92
93         /* endless idle loop with no priority at all */
94         while (1) {
95                 void (*idle)(void) = pm_idle;
96
97                 if (!idle)
98                         idle = default_idle;
99
100                 tick_nohz_stop_sched_tick(1);
101                 while (!need_resched())
102                         idle();
103                 tick_nohz_restart_sched_tick();
104
105                 preempt_enable_no_resched();
106                 schedule();
107                 preempt_disable();
108                 check_pgt_cache();
109         }
110 }
111
112 void flush_thread(void)
113 {
114 }
115
116 int copy_thread(unsigned long clone_flags, unsigned long usp,
117                 unsigned long unused,
118                 struct task_struct *p, struct pt_regs *regs)
119 {
120         struct pt_regs *childregs = task_pt_regs(p);
121         struct thread_info *ti = task_thread_info(p);
122
123         *childregs = *regs;
124         if (user_mode(regs))
125                 childregs->r1 = usp;
126         else
127                 childregs->r1 = ((unsigned long) ti) + THREAD_SIZE;
128
129 #ifndef CONFIG_MMU
130         memset(&ti->cpu_context, 0, sizeof(struct cpu_context));
131         ti->cpu_context.r1 = (unsigned long)childregs;
132         ti->cpu_context.msr = (unsigned long)childregs->msr;
133 #else
134
135         /* if creating a kernel thread then update the current reg (we don't
136          * want to use the parent's value when restoring by POP_STATE) */
137         if (kernel_mode(regs))
138                 /* save new current on stack to use POP_STATE */
139                 childregs->CURRENT_TASK = (unsigned long)p;
140         /* if returning to user then use the parent's value of this register */
141
142         /* if we're creating a new kernel thread then just zeroing all
143          * the registers. That's OK for a brand new thread.*/
144         /* Pls. note that some of them will be restored in POP_STATE */
145         if (kernel_mode(regs))
146                 memset(&ti->cpu_context, 0, sizeof(struct cpu_context));
147         /* if this thread is created for fork/vfork/clone, then we want to
148          * restore all the parent's context */
149         /* in addition to the registers which will be restored by POP_STATE */
150         else {
151                 ti->cpu_context = *(struct cpu_context *)regs;
152                 childregs->msr |= MSR_UMS;
153         }
154
155         /* FIXME STATE_SAVE_PT_OFFSET; */
156         ti->cpu_context.r1  = (unsigned long)childregs - STATE_SAVE_ARG_SPACE;
157         /* we should consider the fact that childregs is a copy of the parent
158          * regs which were saved immediately after entering the kernel state
159          * before enabling VM. This MSR will be restored in switch_to and
160          * RETURN() and we want to have the right machine state there
161          * specifically this state must have INTs disabled before and enabled
162          * after performing rtbd
163          * compose the right MSR for RETURN(). It will work for switch_to also
164          * excepting for VM and UMS
165          * don't touch UMS , CARRY and cache bits
166          * right now MSR is a copy of parent one */
167         childregs->msr |= MSR_BIP;
168         childregs->msr &= ~MSR_EIP;
169         childregs->msr |= MSR_IE;
170         childregs->msr &= ~MSR_VM;
171         childregs->msr |= MSR_VMS;
172         childregs->msr |= MSR_EE; /* exceptions will be enabled*/
173
174         ti->cpu_context.msr = (childregs->msr|MSR_VM);
175         ti->cpu_context.msr &= ~MSR_UMS; /* switch_to to kernel mode */
176 #endif
177         ti->cpu_context.r15 = (unsigned long)ret_from_fork - 8;
178
179         if (clone_flags & CLONE_SETTLS)
180                 ;
181
182         return 0;
183 }
184
185 #ifndef CONFIG_MMU
186 /*
187  * Return saved PC of a blocked thread.
188  */
189 unsigned long thread_saved_pc(struct task_struct *tsk)
190 {
191         struct cpu_context *ctx =
192                 &(((struct thread_info *)(tsk->stack))->cpu_context);
193
194         /* Check whether the thread is blocked in resume() */
195         if (in_sched_functions(ctx->r15))
196                 return (unsigned long)ctx->r15;
197         else
198                 return ctx->r14;
199 }
200 #endif
201
202 static void kernel_thread_helper(int (*fn)(void *), void *arg)
203 {
204         fn(arg);
205         do_exit(-1);
206 }
207
208 int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
209 {
210         struct pt_regs regs;
211
212         memset(&regs, 0, sizeof(regs));
213         /* store them in non-volatile registers */
214         regs.r5 = (unsigned long)fn;
215         regs.r6 = (unsigned long)arg;
216         local_save_flags(regs.msr);
217         regs.pc = (unsigned long)kernel_thread_helper;
218         regs.pt_mode = 1;
219
220         return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
221                         &regs, 0, NULL, NULL);
222 }
223 EXPORT_SYMBOL_GPL(kernel_thread);
224
225 unsigned long get_wchan(struct task_struct *p)
226 {
227 /* TBD (used by procfs) */
228         return 0;
229 }
230
231 /* Set up a thread for executing a new program */
232 void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long usp)
233 {
234         set_fs(USER_DS);
235         regs->pc = pc;
236         regs->r1 = usp;
237         regs->pt_mode = 0;
238 }
239
240 #ifdef CONFIG_MMU
241 #include <linux/elfcore.h>
242 /*
243  * Set up a thread for executing a new program
244  */
245 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpregs)
246 {
247         return 0; /* MicroBlaze has no separate FPU registers */
248 }
249 #endif /* CONFIG_MMU */