1 /*
2 * linux/arch/cris/kernel/process.c
3 *
4 * Copyright (C) 1995 Linus Torvalds
5 * Copyright (C) 2000-2002 Axis Communications AB
6 *
7 * Authors: Bjorn Wesen (bjornw@axis.com)
8 * Mikael Starvik (starvik@axis.com)
9 *
10 * This file handles the architecture-dependent parts of process handling..
11 */
12
13 #include <linux/sched.h>
14 #include <linux/slab.h>
15 #include <linux/err.h>
16 #include <linux/fs.h>
17 #include <arch/svinto.h>
18 #include <linux/init.h>
19 #include <arch/system.h>
20 #include <linux/ptrace.h>
21
22 #ifdef CONFIG_ETRAX_GPIO
23 void etrax_gpio_wake_up_check(void); /* drivers/gpio.c */
24 #endif
25
26 /*
27 * We use this if we don't have any better
28 * idle routine..
29 */
default_idle(void)30 void default_idle(void)
31 {
32 #ifdef CONFIG_ETRAX_GPIO
33 etrax_gpio_wake_up_check();
34 #endif
35 local_irq_enable();
36 }
37
38 /*
39 * Free current thread data structures etc..
40 */
41
exit_thread(void)42 void exit_thread(void)
43 {
44 /* Nothing needs to be done. */
45 }
46
47 /* if the watchdog is enabled, we can simply disable interrupts and go
48 * into an eternal loop, and the watchdog will reset the CPU after 0.1s
49 * if on the other hand the watchdog wasn't enabled, we just enable it and wait
50 */
51
hard_reset_now(void)52 void hard_reset_now (void)
53 {
54 /*
55 * Don't declare this variable elsewhere. We don't want any other
56 * code to know about it than the watchdog handler in entry.S and
57 * this code, implementing hard reset through the watchdog.
58 */
59 #if defined(CONFIG_ETRAX_WATCHDOG)
60 extern int cause_of_death;
61 #endif
62
63 printk("*** HARD RESET ***\n");
64 local_irq_disable();
65
66 #if defined(CONFIG_ETRAX_WATCHDOG)
67 cause_of_death = 0xbedead;
68 #else
69 /* Since we dont plan to keep on resetting the watchdog,
70 the key can be arbitrary hence three */
71 *R_WATCHDOG = IO_FIELD(R_WATCHDOG, key, 3) |
72 IO_STATE(R_WATCHDOG, enable, start);
73 #endif
74
75 while(1) /* waiting for RETRIBUTION! */ ;
76 }
77
78 /*
79 * Return saved PC of a blocked thread.
80 */
thread_saved_pc(struct task_struct * t)81 unsigned long thread_saved_pc(struct task_struct *t)
82 {
83 return task_pt_regs(t)->irp;
84 }
85
86 /* setup the child's kernel stack with a pt_regs and switch_stack on it.
87 * it will be un-nested during _resume and _ret_from_sys_call when the
88 * new thread is scheduled.
89 *
90 * also setup the thread switching structure which is used to keep
91 * thread-specific data during _resumes.
92 *
93 */
94 asmlinkage void ret_from_fork(void);
95 asmlinkage void ret_from_kernel_thread(void);
96
copy_thread(unsigned long clone_flags,unsigned long usp,unsigned long arg,struct task_struct * p)97 int copy_thread(unsigned long clone_flags, unsigned long usp,
98 unsigned long arg, struct task_struct *p)
99 {
100 struct pt_regs *childregs = task_pt_regs(p);
101 struct switch_stack *swstack = ((struct switch_stack *)childregs) - 1;
102
103 /* put the pt_regs structure at the end of the new kernel stack page and fix it up
104 * remember that the task_struct doubles as the kernel stack for the task
105 */
106
107 if (unlikely(p->flags & PF_KTHREAD)) {
108 memset(swstack, 0,
109 sizeof(struct switch_stack) + sizeof(struct pt_regs));
110 swstack->r1 = usp;
111 swstack->r2 = arg;
112 childregs->dccr = 1 << I_DCCR_BITNR;
113 swstack->return_ip = (unsigned long) ret_from_kernel_thread;
114 p->thread.ksp = (unsigned long) swstack;
115 p->thread.usp = 0;
116 return 0;
117 }
118 *childregs = *current_pt_regs(); /* struct copy of pt_regs */
119
120 childregs->r10 = 0; /* child returns 0 after a fork/clone */
121
122 /* put the switch stack right below the pt_regs */
123
124 swstack->r9 = 0; /* parameter to ret_from_sys_call, 0 == dont restart the syscall */
125
126 /* we want to return into ret_from_sys_call after the _resume */
127
128 swstack->return_ip = (unsigned long) ret_from_fork; /* Will call ret_from_sys_call */
129
130 /* fix the user-mode stackpointer */
131
132 p->thread.usp = usp ?: rdusp();
133
134 /* and the kernel-mode one */
135
136 p->thread.ksp = (unsigned long) swstack;
137
138 #ifdef DEBUG
139 printk("copy_thread: new regs at 0x%p, as shown below:\n", childregs);
140 show_registers(childregs);
141 #endif
142
143 return 0;
144 }
145
get_wchan(struct task_struct * p)146 unsigned long get_wchan(struct task_struct *p)
147 {
148 #if 0
149 /* YURGH. TODO. */
150
151 unsigned long ebp, esp, eip;
152 unsigned long stack_page;
153 int count = 0;
154 if (!p || p == current || p->state == TASK_RUNNING)
155 return 0;
156 stack_page = (unsigned long)p;
157 esp = p->thread.esp;
158 if (!stack_page || esp < stack_page || esp > 8188+stack_page)
159 return 0;
160 /* include/asm-i386/system.h:switch_to() pushes ebp last. */
161 ebp = *(unsigned long *) esp;
162 do {
163 if (ebp < stack_page || ebp > 8184+stack_page)
164 return 0;
165 eip = *(unsigned long *) (ebp+4);
166 if (!in_sched_functions(eip))
167 return eip;
168 ebp = *(unsigned long *) ebp;
169 } while (count++ < 16);
170 #endif
171 return 0;
172 }
173 #undef last_sched
174 #undef first_sched
175
show_regs(struct pt_regs * regs)176 void show_regs(struct pt_regs * regs)
177 {
178 unsigned long usp = rdusp();
179
180 show_regs_print_info(KERN_DEFAULT);
181
182 printk("IRP: %08lx SRP: %08lx DCCR: %08lx USP: %08lx MOF: %08lx\n",
183 regs->irp, regs->srp, regs->dccr, usp, regs->mof );
184 printk(" r0: %08lx r1: %08lx r2: %08lx r3: %08lx\n",
185 regs->r0, regs->r1, regs->r2, regs->r3);
186 printk(" r4: %08lx r5: %08lx r6: %08lx r7: %08lx\n",
187 regs->r4, regs->r5, regs->r6, regs->r7);
188 printk(" r8: %08lx r9: %08lx r10: %08lx r11: %08lx\n",
189 regs->r8, regs->r9, regs->r10, regs->r11);
190 printk("r12: %08lx r13: %08lx oR10: %08lx\n",
191 regs->r12, regs->r13, regs->orig_r10);
192 }
193
194