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/* $Id: process.c,v 1.22 2001/11/13 09:40:43 orjanf Exp $
*
* linux/arch/cris/kernel/process.c
*
* Copyright (C) 1995 Linus Torvalds
* Copyright (C) 2000, 2001 Axis Communications AB
*
* Authors: Bjorn Wesen (bjornw@axis.com)
*
* $Log: process.c,v $
* Revision 1.22 2001/11/13 09:40:43 orjanf
* Added dump_fpu (needed for core dumps).
*
* Revision 1.21 2001/11/12 18:26:21 pkj
* Fixed compiler warnings.
*
* Revision 1.20 2001/10/03 08:21:39 jonashg
* cause_of_death does not exist if CONFIG_SVINTO_SIM is defined.
*
* Revision 1.19 2001/09/26 11:52:54 bjornw
* INIT_MMAP is gone in 2.4.10
*
* Revision 1.18 2001/08/21 21:43:51 hp
* Move last watchdog fix inside #ifdef CONFIG_ETRAX_WATCHDOG
*
* Revision 1.17 2001/08/21 13:48:01 jonashg
* Added fix by HP to avoid oops when doing a hard_reset_now.
*
* Revision 1.16 2001/06/21 02:00:40 hp
* * entry.S: Include asm/unistd.h.
* (_sys_call_table): Use section .rodata, not .data.
* (_kernel_thread): Move from...
* * process.c: ... here.
* * entryoffsets.c (VAL): Break out from...
* (OF): Use VAL.
* (LCLONE_VM): New asmified value from CLONE_VM.
*
* Revision 1.15 2001/06/20 16:31:57 hp
* Add comments to describe empty functions according to review.
*
* Revision 1.14 2001/05/29 11:27:59 markusl
* Fixed so that hard_reset_now will do reset even if watchdog wasn't enabled
*
* Revision 1.13 2001/03/20 19:44:06 bjornw
* Use the 7th syscall argument for regs instead of current_regs
*
*/
/*
* This file handles the architecture-dependent parts of process handling..
*/
#define __KERNEL_SYSCALLS__
#include <stdarg.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/user.h>
#include <linux/a.out.h>
#include <linux/elfcore.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <linux/smp.h>
//#define DEBUG
/*
* Initial task structure. Make this a per-architecture thing,
* because different architectures tend to have different
* alignment requirements and potentially different initial
* setup.
*/
static struct fs_struct init_fs = INIT_FS;
static struct files_struct init_files = INIT_FILES;
static struct signal_struct init_signals = INIT_SIGNALS;
struct mm_struct init_mm = INIT_MM(init_mm);
/*
* Initial task structure.
*
* We need to make sure that this is 8192-byte aligned due to the
* way process stacks are handled. This is done by having a special
* "init_task" linker map entry..
*/
union task_union init_task_union
__attribute__((__section__(".data.init_task"))) =
{ INIT_TASK(init_task_union.task) };
/*
* The hlt_counter, disable_hlt and enable_hlt is just here as a hook if
* there would ever be a halt sequence (for power save when idle) with
* some largish delay when halting or resuming *and* a driver that can't
* afford that delay. The hlt_counter would then be checked before
* executing the halt sequence, and the driver marks the unhaltable
* region by enable_hlt/disable_hlt.
*/
static int hlt_counter=0;
void disable_hlt(void)
{
hlt_counter++;
}
void enable_hlt(void)
{
hlt_counter--;
}
int cpu_idle(void *unused)
{
while(1) {
current->counter = -100;
schedule();
}
}
/* 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");
cli();
#if defined(CONFIG_ETRAX_WATCHDOG) && !defined(CONFIG_SVINTO_SIM)
cause_of_death = 0xbedead;
#else
/* Since we dont plan to keep on reseting 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! */ ;
}
void machine_restart(void)
{
hard_reset_now();
}
/*
* Similar to machine_power_off, but don't shut off power. Add code
* here to freeze the system for e.g. post-mortem debug purpose when
* possible. This halt has nothing to do with the idle halt.
*/
void machine_halt(void)
{
}
/* If or when software power-off is implemented, add code here. */
void machine_power_off(void)
{
}
/*
* When a process does an "exec", machine state like FPU and debug
* registers need to be reset. This is a hook function for that.
* Currently we don't have any such state to reset, so this is empty.
*/
void flush_thread(void)
{
}
asmlinkage void ret_from_sys_call(void);
/* 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.
*
*/
int copy_thread(int nr, 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 = user_regs(p);
*childregs = *regs; /* struct copy of pt_regs */
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_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;
}
/*
* fill in the user structure for a core dump..
*/
void dump_thread(struct pt_regs * regs, struct user * dump)
{
#if 0
int i;
/* changed the size calculations - should hopefully work better. lbt */
dump->magic = CMAGIC;
dump->start_code = 0;
dump->start_stack = regs->esp & ~(PAGE_SIZE - 1);
dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT;
dump->u_dsize = ((unsigned long) (current->mm->brk + (PAGE_SIZE-1))) >> PAGE_SHIFT;
dump->u_dsize -= dump->u_tsize;
dump->u_ssize = 0;
for (i = 0; i < 8; i++)
dump->u_debugreg[i] = current->debugreg[i];
if (dump->start_stack < TASK_SIZE)
dump->u_ssize = ((unsigned long) (TASK_SIZE - dump->start_stack)) >> PAGE_SHIFT;
dump->regs = *regs;
dump->u_fpvalid = dump_fpu (regs, &dump->i387);
#endif
}
/* Fill in the fpu structure for a core dump. */
int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
{
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);
}
/* if newusp is 0, we just grab the old usp */
asmlinkage int sys_clone(unsigned long newusp, unsigned long flags,
long r12, long r13, long mof, long srp,
struct pt_regs *regs)
{
if (!newusp)
newusp = rdusp();
return do_fork(flags, newusp, regs, 0);
}
/* 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);
}
/*
* sys_execve() executes a new program.
*/
asmlinkage int sys_execve(const char *fname, char **argv, char **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;
}
/*
* These bracket the sleeping functions..
*/
extern void scheduling_functions_start_here(void);
extern void scheduling_functions_end_here(void);
#define first_sched ((unsigned long) scheduling_functions_start_here)
#define last_sched ((unsigned long) scheduling_functions_end_here)
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 (eip < first_sched || eip >= last_sched)
return eip;
ebp = *(unsigned long *) ebp;
} while (count++ < 16);
#endif
return 0;
}
#undef last_sched
#undef first_sched
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