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