272 lines
7.5 KiB
C
272 lines
7.5 KiB
C
/* $Id: process.c,v 1.12 2004/12/27 11:18:32 starvik Exp $
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*
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* linux/arch/cris/kernel/process.c
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*
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* Copyright (C) 1995 Linus Torvalds
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* Copyright (C) 2000-2002 Axis Communications AB
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*
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* Authors: Bjorn Wesen (bjornw@axis.com)
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* Mikael Starvik (starvik@axis.com)
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*
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* This file handles the architecture-dependent parts of process handling..
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*/
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#include <linux/config.h>
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#include <linux/sched.h>
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#include <linux/err.h>
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#include <linux/fs.h>
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#include <linux/slab.h>
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#include <asm/arch/svinto.h>
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#include <linux/init.h>
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#ifdef CONFIG_ETRAX_GPIO
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void etrax_gpio_wake_up_check(void); /* drivers/gpio.c */
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#endif
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/*
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* We use this if we don't have any better
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* idle routine..
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*/
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void default_idle(void)
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{
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#ifdef CONFIG_ETRAX_GPIO
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etrax_gpio_wake_up_check();
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#endif
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}
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/*
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* Free current thread data structures etc..
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*/
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void exit_thread(void)
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{
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/* Nothing needs to be done. */
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}
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/* if the watchdog is enabled, we can simply disable interrupts and go
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* into an eternal loop, and the watchdog will reset the CPU after 0.1s
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* if on the other hand the watchdog wasn't enabled, we just enable it and wait
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*/
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void hard_reset_now (void)
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{
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/*
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* Don't declare this variable elsewhere. We don't want any other
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* code to know about it than the watchdog handler in entry.S and
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* this code, implementing hard reset through the watchdog.
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*/
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#if defined(CONFIG_ETRAX_WATCHDOG) && !defined(CONFIG_SVINTO_SIM)
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extern int cause_of_death;
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#endif
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printk("*** HARD RESET ***\n");
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local_irq_disable();
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#if defined(CONFIG_ETRAX_WATCHDOG) && !defined(CONFIG_SVINTO_SIM)
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cause_of_death = 0xbedead;
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#else
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/* Since we dont plan to keep on reseting the watchdog,
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the key can be arbitrary hence three */
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*R_WATCHDOG = IO_FIELD(R_WATCHDOG, key, 3) |
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IO_STATE(R_WATCHDOG, enable, start);
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#endif
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while(1) /* waiting for RETRIBUTION! */ ;
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}
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/*
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* Return saved PC of a blocked thread.
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*/
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unsigned long thread_saved_pc(struct task_struct *t)
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{
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return task_pt_regs(t)->irp;
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}
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static void kernel_thread_helper(void* dummy, int (*fn)(void *), void * arg)
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{
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fn(arg);
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do_exit(-1); /* Should never be called, return bad exit value */
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}
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/*
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* Create a kernel thread
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*/
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int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
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{
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struct pt_regs regs;
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memset(®s, 0, sizeof(regs));
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/* Don't use r10 since that is set to 0 in copy_thread */
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regs.r11 = (unsigned long)fn;
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regs.r12 = (unsigned long)arg;
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regs.irp = (unsigned long)kernel_thread_helper;
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regs.dccr = 1 << I_DCCR_BITNR;
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/* Ok, create the new process.. */
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return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, 0, NULL, NULL);
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}
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/* setup the child's kernel stack with a pt_regs and switch_stack on it.
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* it will be un-nested during _resume and _ret_from_sys_call when the
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* new thread is scheduled.
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*
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* also setup the thread switching structure which is used to keep
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* thread-specific data during _resumes.
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*
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*/
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asmlinkage void ret_from_fork(void);
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int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
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unsigned long unused,
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struct task_struct *p, struct pt_regs *regs)
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{
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struct pt_regs * childregs;
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struct switch_stack *swstack;
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/* put the pt_regs structure at the end of the new kernel stack page and fix it up
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* remember that the task_struct doubles as the kernel stack for the task
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*/
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childregs = task_pt_regs(p);
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*childregs = *regs; /* struct copy of pt_regs */
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p->set_child_tid = p->clear_child_tid = NULL;
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childregs->r10 = 0; /* child returns 0 after a fork/clone */
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/* put the switch stack right below the pt_regs */
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swstack = ((struct switch_stack *)childregs) - 1;
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swstack->r9 = 0; /* parameter to ret_from_sys_call, 0 == dont restart the syscall */
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/* we want to return into ret_from_sys_call after the _resume */
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swstack->return_ip = (unsigned long) ret_from_fork; /* Will call ret_from_sys_call */
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/* fix the user-mode stackpointer */
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p->thread.usp = usp;
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/* and the kernel-mode one */
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p->thread.ksp = (unsigned long) swstack;
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#ifdef DEBUG
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printk("copy_thread: new regs at 0x%p, as shown below:\n", childregs);
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show_registers(childregs);
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#endif
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return 0;
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}
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/*
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* Be aware of the "magic" 7th argument in the four system-calls below.
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* They need the latest stackframe, which is put as the 7th argument by
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* entry.S. The previous arguments are dummies or actually used, but need
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* to be defined to reach the 7th argument.
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*
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* N.B.: Another method to get the stackframe is to use current_regs(). But
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* it returns the latest stack-frame stacked when going from _user mode_ and
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* some of these (at least sys_clone) are called from kernel-mode sometimes
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* (for example during kernel_thread, above) and thus cannot use it. Thus,
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* to be sure not to get any surprises, we use the method for the other calls
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* as well.
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*/
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asmlinkage int sys_fork(long r10, long r11, long r12, long r13, long mof, long srp,
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struct pt_regs *regs)
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{
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return do_fork(SIGCHLD, rdusp(), regs, 0, NULL, NULL);
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}
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/* if newusp is 0, we just grab the old usp */
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/* FIXME: Is parent_tid/child_tid really third/fourth argument? Update lib? */
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asmlinkage int sys_clone(unsigned long newusp, unsigned long flags,
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int* parent_tid, int* child_tid, long mof, long srp,
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struct pt_regs *regs)
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{
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if (!newusp)
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newusp = rdusp();
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return do_fork(flags, newusp, regs, 0, parent_tid, child_tid);
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}
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/* vfork is a system call in i386 because of register-pressure - maybe
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* we can remove it and handle it in libc but we put it here until then.
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*/
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asmlinkage int sys_vfork(long r10, long r11, long r12, long r13, long mof, long srp,
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struct pt_regs *regs)
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{
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return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL, NULL);
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}
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/*
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* sys_execve() executes a new program.
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*/
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asmlinkage int sys_execve(const char *fname, char **argv, char **envp,
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long r13, long mof, long srp,
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struct pt_regs *regs)
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{
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int error;
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char *filename;
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filename = getname(fname);
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error = PTR_ERR(filename);
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if (IS_ERR(filename))
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goto out;
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error = do_execve(filename, argv, envp, regs);
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putname(filename);
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out:
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return error;
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}
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unsigned long get_wchan(struct task_struct *p)
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{
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#if 0
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/* YURGH. TODO. */
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unsigned long ebp, esp, eip;
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unsigned long stack_page;
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int count = 0;
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if (!p || p == current || p->state == TASK_RUNNING)
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return 0;
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stack_page = (unsigned long)p;
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esp = p->thread.esp;
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if (!stack_page || esp < stack_page || esp > 8188+stack_page)
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return 0;
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/* include/asm-i386/system.h:switch_to() pushes ebp last. */
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ebp = *(unsigned long *) esp;
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do {
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if (ebp < stack_page || ebp > 8184+stack_page)
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return 0;
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eip = *(unsigned long *) (ebp+4);
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if (!in_sched_functions(eip))
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return eip;
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ebp = *(unsigned long *) ebp;
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} while (count++ < 16);
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#endif
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return 0;
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}
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#undef last_sched
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#undef first_sched
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void show_regs(struct pt_regs * regs)
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{
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unsigned long usp = rdusp();
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printk("IRP: %08lx SRP: %08lx DCCR: %08lx USP: %08lx MOF: %08lx\n",
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regs->irp, regs->srp, regs->dccr, usp, regs->mof );
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printk(" r0: %08lx r1: %08lx r2: %08lx r3: %08lx\n",
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regs->r0, regs->r1, regs->r2, regs->r3);
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printk(" r4: %08lx r5: %08lx r6: %08lx r7: %08lx\n",
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regs->r4, regs->r5, regs->r6, regs->r7);
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printk(" r8: %08lx r9: %08lx r10: %08lx r11: %08lx\n",
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regs->r8, regs->r9, regs->r10, regs->r11);
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printk("r12: %08lx r13: %08lx oR10: %08lx\n",
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regs->r12, regs->r13, regs->orig_r10);
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}
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