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* linux/arch/i386/kernel/process.c
*
* Copyright (C) 1995 Linus Torvalds
*/
/*
* 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/malloc.h>
#include <linux/ldt.h>
#include <linux/user.h>
#include <linux/a.out.h>
#include <linux/interrupt.h>
#include <linux/config.h>
#include <linux/unistd.h>
#include <asm/segment.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/io.h>
#include <linux/smp.h>
asmlinkage void ret_from_sys_call(void) __asm__("ret_from_sys_call");
#ifdef CONFIG_APM
extern int apm_do_idle(void);
extern void apm_do_busy(void);
#endif
static int hlt_counter=0;
#define HARD_IDLE_TIMEOUT (HZ / 3)
void disable_hlt(void)
{
hlt_counter++;
}
void enable_hlt(void)
{
hlt_counter--;
}
#ifndef __SMP__
static void hard_idle(void)
{
while (!need_resched) {
if (hlt_works_ok && !hlt_counter) {
#ifdef CONFIG_APM
/* If the APM BIOS is not enabled, or there
is an error calling the idle routine, we
should hlt if possible. We need to check
need_resched again because an interrupt
may have occured in apm_do_idle(). */
start_bh_atomic();
if (!apm_do_idle() && !need_resched)
__asm__("hlt");
end_bh_atomic();
#else
__asm__("hlt");
#endif
}
if (need_resched)
break;
schedule();
}
#ifdef CONFIG_APM
apm_do_busy();
#endif
}
/*
* The idle loop on a uniprocessor i386..
*/
asmlinkage int sys_idle(void)
{
unsigned long start_idle = 0;
if (current->pid != 0)
return -EPERM;
/* endless idle loop with no priority at all */
current->counter = -100;
for (;;)
{
/*
* We are locked at this point. So we can safely call
* the APM bios knowing only one CPU at a time will do
* so.
*/
if (!start_idle)
start_idle = jiffies;
if (jiffies - start_idle > HARD_IDLE_TIMEOUT)
{
hard_idle();
}
else
{
if (hlt_works_ok && !hlt_counter && !need_resched)
__asm__("hlt");
}
if (need_resched)
start_idle = 0;
schedule();
}
}
#else
/*
* In the SMP world we hlt outside of kernel syscall rather than within
* so as to get the right locking semantics.
*/
asmlinkage int sys_idle(void)
{
if(current->pid != 0)
return -EPERM;
#ifdef __SMP_PROF__
smp_spins_sys_idle[smp_processor_id()]+=
smp_spins_syscall_cur[smp_processor_id()];
#endif
current->counter= -100;
schedule();
return 0;
}
/*
* This is being executed in task 0 'user space'.
*/
int cpu_idle(void *unused)
{
while(1)
{
if(cpu_data[smp_processor_id()].hlt_works_ok && !hlt_counter && !need_resched)
__asm("hlt");
idle();
}
}
#endif
/*
* This routine reboots the machine by asking the keyboard
* controller to pulse the reset-line low. We try that for a while,
* and if it doesn't work, we do some other stupid things.
*/
static long no_idt[2] = {0, 0};
static inline void kb_wait(void)
{
int i;
for (i=0; i<0x10000; i++)
if ((inb_p(0x64) & 0x02) == 0)
break;
}
void hard_reset_now(void)
{
int i, j;
sti();
/* rebooting needs to touch the page at absolute addr 0 */
pg0[0] = 7;
*((unsigned short *)0x472) = 0x1234;
for (;;) {
for (i=0; i<100; i++) {
kb_wait();
for(j = 0; j < 100000 ; j++)
/* nothing */;
outb(0xfe,0x64); /* pulse reset low */
}
__asm__ __volatile__("\tlidt %0": "=m" (no_idt));
}
}
void show_regs(struct pt_regs * regs)
{
printk("\n");
printk("EIP: %04x:[<%08lx>]",0xffff & regs->cs,regs->eip);
if (regs->cs & 3)
printk(" ESP: %04x:%08lx",0xffff & regs->ss,regs->esp);
printk(" EFLAGS: %08lx\n",regs->eflags);
printk("EAX: %08lx EBX: %08lx ECX: %08lx EDX: %08lx\n",
regs->eax,regs->ebx,regs->ecx,regs->edx);
printk("ESI: %08lx EDI: %08lx EBP: %08lx",
regs->esi, regs->edi, regs->ebp);
printk(" DS: %04x ES: %04x FS: %04x GS: %04x\n",
0xffff & regs->ds,0xffff & regs->es,
0xffff & regs->fs,0xffff & regs->gs);
}
/*
* Free current thread data structures etc..
*/
void exit_thread(void)
{
/* forget lazy i387 state */
if (last_task_used_math == current)
last_task_used_math = NULL;
/* forget local segments */
__asm__ __volatile__("mov %w0,%%fs ; mov %w0,%%gs ; lldt %w0"
: /* no outputs */
: "r" (0));
current->tss.ldt = 0;
if (current->ldt) {
void * ldt = current->ldt;
current->ldt = NULL;
vfree(ldt);
}
}
void flush_thread(void)
{
int i;
if (current->ldt) {
free_page((unsigned long) current->ldt);
current->ldt = NULL;
for (i=1 ; i<NR_TASKS ; i++) {
if (task[i] == current) {
set_ldt_desc(gdt+(i<<1)+
FIRST_LDT_ENTRY,&default_ldt, 1);
load_ldt(i);
}
}
}
for (i=0 ; i<8 ; i++)
current->debugreg[i] = 0;
}
void release_thread(struct task_struct *dead_task)
{
}
void copy_thread(int nr, unsigned long clone_flags, unsigned long esp,
struct task_struct * p, struct pt_regs * regs)
{
int i;
struct pt_regs * childregs;
p->tss.es = KERNEL_DS;
p->tss.cs = KERNEL_CS;
p->tss.ss = KERNEL_DS;
p->tss.ds = KERNEL_DS;
p->tss.fs = USER_DS;
p->tss.gs = KERNEL_DS;
p->tss.ss0 = KERNEL_DS;
p->tss.esp0 = p->kernel_stack_page + PAGE_SIZE;
p->tss.tr = _TSS(nr);
childregs = ((struct pt_regs *) (p->kernel_stack_page + PAGE_SIZE)) - 1;
p->tss.esp = (unsigned long) childregs;
p->tss.eip = (unsigned long) ret_from_sys_call;
*childregs = *regs;
childregs->eax = 0;
childregs->esp = esp;
p->tss.back_link = 0;
p->tss.eflags = regs->eflags & 0xffffcfff; /* iopl is always 0 for a new process */
p->tss.ldt = _LDT(nr);
if (p->ldt) {
p->ldt = (struct desc_struct*) vmalloc(LDT_ENTRIES*LDT_ENTRY_SIZE);
if (p->ldt != NULL)
memcpy(p->ldt, current->ldt, LDT_ENTRIES*LDT_ENTRY_SIZE);
}
set_tss_desc(gdt+(nr<<1)+FIRST_TSS_ENTRY,&(p->tss));
if (p->ldt)
set_ldt_desc(gdt+(nr<<1)+FIRST_LDT_ENTRY,p->ldt, 512);
else
set_ldt_desc(gdt+(nr<<1)+FIRST_LDT_ENTRY,&default_ldt, 1);
p->tss.bitmap = offsetof(struct thread_struct,io_bitmap);
for (i = 0; i < IO_BITMAP_SIZE+1 ; i++) /* IO bitmap is actually SIZE+1 */
p->tss.io_bitmap[i] = ~0;
if (last_task_used_math == current)
__asm__("clts ; fnsave %0 ; frstor %0":"=m" (p->tss.i387));
}
/*
* fill in the fpu structure for a core dump..
*/
int dump_fpu (struct user_i387_struct* fpu)
{
int fpvalid;
/* Flag indicating the math stuff is valid. We don't support this for the
soft-float routines yet */
if (hard_math) {
if ((fpvalid = current->used_math) != 0) {
if (last_task_used_math == current)
__asm__("clts ; fnsave %0": :"m" (*fpu));
else
memcpy(fpu,¤t->tss.i387.hard,sizeof(*fpu));
}
} else {
/* we should dump the emulator state here, but we need to
convert it into standard 387 format first.. */
fpvalid = 0;
}
return fpvalid;
}
/*
* fill in the user structure for a core dump..
*/
void dump_thread(struct pt_regs * regs, struct user * dump)
{
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 (&dump->i387);
}
asmlinkage int sys_fork(struct pt_regs regs)
{
return do_fork(SIGCHLD, regs.esp, ®s);
}
asmlinkage int sys_clone(struct pt_regs regs)
{
unsigned long clone_flags;
unsigned long newsp;
clone_flags = regs.ebx;
newsp = regs.ecx;
if (!newsp)
newsp = regs.esp;
return do_fork(clone_flags, newsp, ®s);
}
/*
* sys_execve() executes a new program.
*/
asmlinkage int sys_execve(struct pt_regs regs)
{
int error;
char * filename;
error = getname((char *) regs.ebx, &filename);
if (error)
return error;
error = do_execve(filename, (char **) regs.ecx, (char **) regs.edx, ®s);
putname(filename);
return error;
}
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