Merge branch 'next' of git://git.monstr.eu/linux-2.6-microblaze
[~shefty/rdma-dev.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/export.h>
12 #include <linux/sched.h>
13 #include <linux/pm.h>
14 #include <linux/tick.h>
15 #include <linux/bitops.h>
16 #include <linux/ptrace.h>
17 #include <asm/pgalloc.h>
18 #include <linux/uaccess.h> /* for USER_DS macros */
19 #include <asm/cacheflush.h>
20
21 void show_regs(struct pt_regs *regs)
22 {
23         pr_info(" Registers dump: mode=%X\r\n", regs->pt_mode);
24         pr_info(" r1=%08lX, r2=%08lX, r3=%08lX, r4=%08lX\n",
25                                 regs->r1, regs->r2, regs->r3, regs->r4);
26         pr_info(" r5=%08lX, r6=%08lX, r7=%08lX, r8=%08lX\n",
27                                 regs->r5, regs->r6, regs->r7, regs->r8);
28         pr_info(" r9=%08lX, r10=%08lX, r11=%08lX, r12=%08lX\n",
29                                 regs->r9, regs->r10, regs->r11, regs->r12);
30         pr_info(" r13=%08lX, r14=%08lX, r15=%08lX, r16=%08lX\n",
31                                 regs->r13, regs->r14, regs->r15, regs->r16);
32         pr_info(" r17=%08lX, r18=%08lX, r19=%08lX, r20=%08lX\n",
33                                 regs->r17, regs->r18, regs->r19, regs->r20);
34         pr_info(" r21=%08lX, r22=%08lX, r23=%08lX, r24=%08lX\n",
35                                 regs->r21, regs->r22, regs->r23, regs->r24);
36         pr_info(" r25=%08lX, r26=%08lX, r27=%08lX, r28=%08lX\n",
37                                 regs->r25, regs->r26, regs->r27, regs->r28);
38         pr_info(" r29=%08lX, r30=%08lX, r31=%08lX, rPC=%08lX\n",
39                                 regs->r29, regs->r30, regs->r31, regs->pc);
40         pr_info(" msr=%08lX, ear=%08lX, esr=%08lX, fsr=%08lX\n",
41                                 regs->msr, regs->ear, regs->esr, regs->fsr);
42 }
43
44 void (*pm_power_off)(void) = NULL;
45 EXPORT_SYMBOL(pm_power_off);
46
47 static int hlt_counter = 1;
48
49 void disable_hlt(void)
50 {
51         hlt_counter++;
52 }
53 EXPORT_SYMBOL(disable_hlt);
54
55 void enable_hlt(void)
56 {
57         hlt_counter--;
58 }
59 EXPORT_SYMBOL(enable_hlt);
60
61 static int __init nohlt_setup(char *__unused)
62 {
63         hlt_counter = 1;
64         return 1;
65 }
66 __setup("nohlt", nohlt_setup);
67
68 static int __init hlt_setup(char *__unused)
69 {
70         hlt_counter = 0;
71         return 1;
72 }
73 __setup("hlt", hlt_setup);
74
75 void default_idle(void)
76 {
77         if (likely(hlt_counter)) {
78                 local_irq_disable();
79                 stop_critical_timings();
80                 cpu_relax();
81                 start_critical_timings();
82                 local_irq_enable();
83         } else {
84                 clear_thread_flag(TIF_POLLING_NRFLAG);
85                 smp_mb__after_clear_bit();
86                 local_irq_disable();
87                 while (!need_resched())
88                         cpu_sleep();
89                 local_irq_enable();
90                 set_thread_flag(TIF_POLLING_NRFLAG);
91         }
92 }
93
94 void cpu_idle(void)
95 {
96         set_thread_flag(TIF_POLLING_NRFLAG);
97
98         /* endless idle loop with no priority at all */
99         while (1) {
100                 tick_nohz_idle_enter();
101                 rcu_idle_enter();
102                 while (!need_resched())
103                         default_idle();
104                 rcu_idle_exit();
105                 tick_nohz_idle_exit();
106
107                 schedule_preempt_disabled();
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 arg, struct task_struct *p)
118 {
119         struct pt_regs *childregs = task_pt_regs(p);
120         struct thread_info *ti = task_thread_info(p);
121
122         if (unlikely(p->flags & PF_KTHREAD)) {
123                 /* if we're creating a new kernel thread then just zeroing all
124                  * the registers. That's OK for a brand new thread.*/
125                 memset(childregs, 0, sizeof(struct pt_regs));
126                 memset(&ti->cpu_context, 0, sizeof(struct cpu_context));
127                 ti->cpu_context.r1  = (unsigned long)childregs;
128                 ti->cpu_context.r20 = (unsigned long)usp; /* fn */
129                 ti->cpu_context.r19 = (unsigned long)arg;
130                 childregs->pt_mode = 1;
131                 local_save_flags(childregs->msr);
132 #ifdef CONFIG_MMU
133                 ti->cpu_context.msr = childregs->msr & ~MSR_IE;
134 #endif
135                 ti->cpu_context.r15 = (unsigned long)ret_from_kernel_thread - 8;
136                 return 0;
137         }
138         *childregs = *current_pt_regs();
139         if (usp)
140                 childregs->r1 = usp;
141
142         memset(&ti->cpu_context, 0, sizeof(struct cpu_context));
143         ti->cpu_context.r1 = (unsigned long)childregs;
144 #ifndef CONFIG_MMU
145         ti->cpu_context.msr = (unsigned long)childregs->msr;
146 #else
147         childregs->msr |= MSR_UMS;
148
149         /* we should consider the fact that childregs is a copy of the parent
150          * regs which were saved immediately after entering the kernel state
151          * before enabling VM. This MSR will be restored in switch_to and
152          * RETURN() and we want to have the right machine state there
153          * specifically this state must have INTs disabled before and enabled
154          * after performing rtbd
155          * compose the right MSR for RETURN(). It will work for switch_to also
156          * excepting for VM and UMS
157          * don't touch UMS , CARRY and cache bits
158          * right now MSR is a copy of parent one */
159         childregs->msr &= ~MSR_EIP;
160         childregs->msr |= MSR_IE;
161         childregs->msr &= ~MSR_VM;
162         childregs->msr |= MSR_VMS;
163         childregs->msr |= MSR_EE; /* exceptions will be enabled*/
164
165         ti->cpu_context.msr = (childregs->msr|MSR_VM);
166         ti->cpu_context.msr &= ~MSR_UMS; /* switch_to to kernel mode */
167         ti->cpu_context.msr &= ~MSR_IE;
168 #endif
169         ti->cpu_context.r15 = (unsigned long)ret_from_fork - 8;
170
171         /*
172          *  r21 is the thread reg, r10 is 6th arg to clone
173          *  which contains TLS area
174          */
175         if (clone_flags & CLONE_SETTLS)
176                 childregs->r21 = childregs->r10;
177
178         return 0;
179 }
180
181 #ifndef CONFIG_MMU
182 /*
183  * Return saved PC of a blocked thread.
184  */
185 unsigned long thread_saved_pc(struct task_struct *tsk)
186 {
187         struct cpu_context *ctx =
188                 &(((struct thread_info *)(tsk->stack))->cpu_context);
189
190         /* Check whether the thread is blocked in resume() */
191         if (in_sched_functions(ctx->r15))
192                 return (unsigned long)ctx->r15;
193         else
194                 return ctx->r14;
195 }
196 #endif
197
198 unsigned long get_wchan(struct task_struct *p)
199 {
200 /* TBD (used by procfs) */
201         return 0;
202 }
203
204 /* Set up a thread for executing a new program */
205 void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long usp)
206 {
207         regs->pc = pc;
208         regs->r1 = usp;
209         regs->pt_mode = 0;
210 #ifdef CONFIG_MMU
211         regs->msr |= MSR_UMS;
212         regs->msr &= ~MSR_VM;
213 #endif
214 }
215
216 #ifdef CONFIG_MMU
217 #include <linux/elfcore.h>
218 /*
219  * Set up a thread for executing a new program
220  */
221 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpregs)
222 {
223         return 0; /* MicroBlaze has no separate FPU registers */
224 }
225 #endif /* CONFIG_MMU */