1 /* $Id: process.c,v 1.3 2003/07/04 08:27:41 starvik Exp $
3 * linux/arch/cris/kernel/process.c
5 * Copyright (C) 1995 Linus Torvalds
6 * Copyright (C) 2000-2002 Axis Communications AB
8 * Authors: Bjorn Wesen (bjornw@axis.com)
9 * Mikael Starvik (starvik@axis.com)
11 * This file handles the architecture-dependent parts of process handling..
14 #include <linux/config.h>
15 #include <linux/sched.h>
16 #include <linux/err.h>
18 #include <linux/slab.h>
19 #include <linux/init.h>
21 #ifdef CONFIG_ETRAX_GPIO
22 void etrax_gpio_wake_up_check(void); /* drivers/gpio.c */
26 * We use this if we don't have any better
29 void default_idle(void)
31 #ifdef CONFIG_ETRAX_GPIO
32 etrax_gpio_wake_up_check();
36 /* if the watchdog is enabled, we can simply disable interrupts and go
37 * into an eternal loop, and the watchdog will reset the CPU after 0.1s
38 * if on the other hand the watchdog wasn't enabled, we just enable it and wait
41 void hard_reset_now (void)
44 * Don't declare this variable elsewhere. We don't want any other
45 * code to know about it than the watchdog handler in entry.S and
46 * this code, implementing hard reset through the watchdog.
48 #if defined(CONFIG_ETRAX_WATCHDOG) && !defined(CONFIG_SVINTO_SIM)
49 extern int cause_of_death;
52 printk("*** HARD RESET ***\n");
55 #if defined(CONFIG_ETRAX_WATCHDOG) && !defined(CONFIG_SVINTO_SIM)
56 cause_of_death = 0xbedead;
58 /* Since we dont plan to keep on reseting the watchdog,
59 the key can be arbitrary hence three */
60 *R_WATCHDOG = IO_FIELD(R_WATCHDOG, key, 3) |
61 IO_STATE(R_WATCHDOG, enable, start);
64 while(1) /* waiting for RETRIBUTION! */ ;
68 * Return saved PC of a blocked thread.
70 unsigned long thread_saved_pc(struct task_struct *t)
72 return (unsigned long)user_regs(t->thread_info)->irp;
75 static void kernel_thread_helper(void* dummy, int (*fn)(void *), void * arg)
78 do_exit(-1); /* Should never be called, return bad exit value */
82 * Create a kernel thread
84 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
88 memset(®s, 0, sizeof(regs));
90 /* Don't use r10 since that is set to 0 in copy_thread */
91 regs.r11 = (unsigned long)fn;
92 regs.r12 = (unsigned long)arg;
93 regs.irp = (unsigned long)kernel_thread_helper;
95 /* Ok, create the new process.. */
96 return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, 0, NULL, NULL);
99 /* setup the child's kernel stack with a pt_regs and switch_stack on it.
100 * it will be un-nested during _resume and _ret_from_sys_call when the
101 * new thread is scheduled.
103 * also setup the thread switching structure which is used to keep
104 * thread-specific data during _resumes.
107 asmlinkage void ret_from_fork(void);
109 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
110 unsigned long unused,
111 struct task_struct *p, struct pt_regs *regs)
113 struct pt_regs * childregs;
114 struct switch_stack *swstack;
116 /* put the pt_regs structure at the end of the new kernel stack page and fix it up
117 * remember that the task_struct doubles as the kernel stack for the task
120 childregs = user_regs(p->thread_info);
122 *childregs = *regs; /* struct copy of pt_regs */
124 p->set_child_tid = p->clear_child_tid = NULL;
126 childregs->r10 = 0; /* child returns 0 after a fork/clone */
128 /* put the switch stack right below the pt_regs */
130 swstack = ((struct switch_stack *)childregs) - 1;
132 swstack->r9 = 0; /* parameter to ret_from_sys_call, 0 == dont restart the syscall */
134 /* we want to return into ret_from_sys_call after the _resume */
136 swstack->return_ip = (unsigned long) ret_from_fork; /* Will call ret_from_sys_call */
138 /* fix the user-mode stackpointer */
142 /* and the kernel-mode one */
144 p->thread.ksp = (unsigned long) swstack;
147 printk("copy_thread: new regs at 0x%p, as shown below:\n", childregs);
148 show_registers(childregs);
155 * Be aware of the "magic" 7th argument in the four system-calls below.
156 * They need the latest stackframe, which is put as the 7th argument by
157 * entry.S. The previous arguments are dummies or actually used, but need
158 * to be defined to reach the 7th argument.
160 * N.B.: Another method to get the stackframe is to use current_regs(). But
161 * it returns the latest stack-frame stacked when going from _user mode_ and
162 * some of these (at least sys_clone) are called from kernel-mode sometimes
163 * (for example during kernel_thread, above) and thus cannot use it. Thus,
164 * to be sure not to get any surprises, we use the method for the other calls
168 asmlinkage int sys_fork(long r10, long r11, long r12, long r13, long mof, long srp,
169 struct pt_regs *regs)
171 return do_fork(SIGCHLD, rdusp(), regs, 0, NULL, NULL);
174 /* if newusp is 0, we just grab the old usp */
175 /* FIXME: Is parent_tid/child_tid really third/fourth argument? Update lib? */
176 asmlinkage int sys_clone(unsigned long newusp, unsigned long flags,
177 int* parent_tid, int* child_tid, long mof, long srp,
178 struct pt_regs *regs)
182 return do_fork(flags & ~CLONE_IDLETASK, newusp, regs, 0, parent_tid, child_tid);
185 /* vfork is a system call in i386 because of register-pressure - maybe
186 * we can remove it and handle it in libc but we put it here until then.
189 asmlinkage int sys_vfork(long r10, long r11, long r12, long r13, long mof, long srp,
190 struct pt_regs *regs)
192 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL, NULL);
196 * sys_execve() executes a new program.
198 asmlinkage int sys_execve(const char *fname, char **argv, char **envp,
199 long r13, long mof, long srp,
200 struct pt_regs *regs)
205 filename = getname(fname);
206 error = PTR_ERR(filename);
208 if (IS_ERR(filename))
210 error = do_execve(filename, argv, envp, regs);
217 * These bracket the sleeping functions..
220 #define first_sched ((unsigned long) scheduling_functions_start_here)
221 #define last_sched ((unsigned long) scheduling_functions_end_here)
223 unsigned long get_wchan(struct task_struct *p)
228 unsigned long ebp, esp, eip;
229 unsigned long stack_page;
231 if (!p || p == current || p->state == TASK_RUNNING)
233 stack_page = (unsigned long)p;
235 if (!stack_page || esp < stack_page || esp > 8188+stack_page)
237 /* include/asm-i386/system.h:switch_to() pushes ebp last. */
238 ebp = *(unsigned long *) esp;
240 if (ebp < stack_page || ebp > 8184+stack_page)
242 eip = *(unsigned long *) (ebp+4);
243 if (eip < first_sched || eip >= last_sched)
245 ebp = *(unsigned long *) ebp;
246 } while (count++ < 16);