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/* $Id: process.c,v 1.12 1999/06/17 13:25:46 ralf Exp $
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1994 - 1998 by Ralf Baechle and others.
*/
#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/mman.h>
#include <linux/sys.h>
#include <linux/user.h>
#include <linux/a.out.h>
#include <asm/bootinfo.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/mipsregs.h>
#include <asm/processor.h>
#include <asm/stackframe.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/elf.h>
#include <asm/isadep.h>
struct task_struct *last_task_used_math = NULL;
asmlinkage void ret_from_sys_call(void);
/*
* Do necessary setup to start up a newly executed thread.
*/
void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
{
/* New thread looses kernel privileges. */
regs->cp0_status = (regs->cp0_status & ~(ST0_CU0|KU_MASK)) | KU_USER;
regs->cp0_epc = pc;
regs->regs[29] = sp;
current->tss.current_ds = USER_DS;
}
void exit_thread(void)
{
/* Forget lazy fpu state */
if (last_task_used_math == current) {
set_cp0_status(ST0_CU1, ST0_CU1);
__asm__ __volatile__("cfc1\t$0,$31");
last_task_used_math = NULL;
}
}
void flush_thread(void)
{
/* Forget lazy fpu state */
if (last_task_used_math == current) {
set_cp0_status(ST0_CU1, ST0_CU1);
__asm__ __volatile__("cfc1\t$0,$31");
last_task_used_math = NULL;
}
}
void release_thread(struct task_struct *dead_task)
{
}
int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
struct task_struct * p, struct pt_regs * regs)
{
struct pt_regs * childregs;
long childksp;
extern void (*save_fp)(struct sigcontext *);
childksp = (unsigned long)p + KERNEL_STACK_SIZE - 32;
if (last_task_used_math == current) {
set_cp0_status(ST0_CU1, ST0_CU1);
save_fp(p);
}
/* set up new TSS. */
childregs = (struct pt_regs *) childksp - 1;
*childregs = *regs;
childregs->regs[7] = 0; /* Clear error flag */
if(current->personality == PER_LINUX) {
childregs->regs[2] = 0; /* Child gets zero as return value */
regs->regs[2] = p->pid;
} else {
/* Under IRIX things are a little different. */
childregs->regs[2] = 0;
childregs->regs[3] = 1;
regs->regs[2] = p->pid;
regs->regs[3] = 0;
}
if (childregs->cp0_status & ST0_CU0) {
childregs->regs[28] = (unsigned long) p;
childregs->regs[29] = childksp;
p->tss.current_ds = KERNEL_DS;
} else {
childregs->regs[29] = usp;
p->tss.current_ds = USER_DS;
}
p->tss.reg29 = (unsigned long) childregs;
p->tss.reg31 = (unsigned long) ret_from_sys_call;
/*
* New tasks loose permission to use the fpu. This accelerates context
* switching for most programs since they don't use the fpu.
*/
p->tss.cp0_status = read_32bit_cp0_register(CP0_STATUS) &
~(ST0_CU3|ST0_CU2|ST0_CU1|KU_MASK);
childregs->cp0_status &= ~(ST0_CU3|ST0_CU2|ST0_CU1);
p->mm->context = 0;
return 0;
}
/* Fill in the fpu structure for a core dump.. */
int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r)
{
/* We actually store the FPU info in the task->tss
* area.
*/
if(regs->cp0_status & ST0_CU1) {
memcpy(r, ¤t->tss.fpu, sizeof(current->tss.fpu));
return 1;
}
return 0; /* Task didn't use the fpu at all. */
}
/* Fill in the user structure for a core dump.. */
void dump_thread(struct pt_regs *regs, struct user *dump)
{
dump->magic = CMAGIC;
dump->start_code = current->mm->start_code;
dump->start_data = current->mm->start_data;
dump->start_stack = regs->regs[29] & ~(PAGE_SIZE - 1);
dump->u_tsize = (current->mm->end_code - dump->start_code) >> PAGE_SHIFT;
dump->u_dsize = (current->mm->brk + (PAGE_SIZE - 1) - dump->start_data) >> PAGE_SHIFT;
dump->u_ssize =
(current->mm->start_stack - dump->start_stack + PAGE_SIZE - 1) >> PAGE_SHIFT;
memcpy(&dump->regs[0], regs, sizeof(struct pt_regs));
memcpy(&dump->regs[EF_SIZE/4], ¤t->tss.fpu, sizeof(current->tss.fpu));
}
/*
* Create a kernel thread
*/
int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
{
long retval;
__asm__ __volatile__(
".set\tnoreorder\n\t"
"move\t$6,$sp\n\t"
"move\t$4,%5\n\t"
"li\t$2,%1\n\t"
"syscall\n\t"
"beq\t$6,$sp,1f\n\t"
"subu\t$sp,32\n\t" /* delay slot */
"jalr\t%4\n\t"
"move\t$4,%3\n\t" /* delay slot */
"move\t$4,$2\n\t"
"li\t$2,%2\n\t"
"syscall\n"
"1:\taddiu\t$sp,32\n\t"
"move\t%0,$2\n\t"
".set\treorder"
:"=r" (retval)
:"i" (__NR_clone), "i" (__NR_exit),
"r" (arg), "r" (fn),
"r" (flags | CLONE_VM)
/*
* The called subroutine might have destroyed any of the
* at, result, argument or temporary registers ...
*/
:"$1", "$2", "$3", "$4", "$5", "$6", "$7", "$8",
"$9","$10","$11","$12","$13","$14","$15","$24","$25");
return retval;
}
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