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/*
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* linux/kernel/fork.c
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*
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* (C) 1991 Linus Torvalds
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*/
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/*
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* 'fork.c' contains the help-routines for the 'fork' system call
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* (see also system_call.s), and some misc functions ('verify_area').
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* Fork is rather simple, once you get the hang of it, but the memory
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* management can be a bitch. See 'mm/mm.c': 'copy_page_tables()'
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*/
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#include <errno.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <asm/segment.h>
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#include <asm/system.h>
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/*****************************/
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#include <unistd.h>
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/*****************************/
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extern void write_verify(unsigned long address);
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long last_pid = 0;
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void verify_area(void* addr, int size)
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{
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unsigned long start;
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start = (unsigned long)addr;
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size += start & 0xfff;
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start &= 0xfffff000;
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start += get_base(current->ldt[2]);
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while (size > 0) {
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size -= 4096;
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write_verify(start);
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start += 4096;
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}
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}
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int copy_mem(int nr, struct task_struct* p)
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{
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unsigned long old_data_base, new_data_base, data_limit;
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unsigned long old_code_base, new_code_base, code_limit;
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code_limit = get_limit(0x0f);
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data_limit = get_limit(0x17);
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old_code_base = get_base(current->ldt[1]);
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old_data_base = get_base(current->ldt[2]);
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if (old_data_base != old_code_base)
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panic("We don't support separate I&D");
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if (data_limit < code_limit)
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panic("Bad data_limit");
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new_data_base = new_code_base = nr * 0x4000000;
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p->start_code = new_code_base;
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set_base(p->ldt[1], new_code_base);
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set_base(p->ldt[2], new_data_base);
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if (copy_page_tables(old_data_base, new_data_base, data_limit)) {
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printk("free_page_tables: from copy_mem\n");
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free_page_tables(new_data_base, data_limit);
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return -ENOMEM;
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}
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return 0;
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}
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/*
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* Ok, this is the main fork-routine. It copies the system process
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* information (task[nr]) and sets up the necessary registers. It
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* also copies the data segment in it's entirety.
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*/
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int copy_process(int nr, long ebp, long edi, long esi, long gs, long none,
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long ebx, long ecx, long edx,
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long fs, long es, long ds,
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long eip, long cs, long eflags, long esp, long ss)
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{
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struct task_struct* p;
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int i;
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struct file* f;
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p = (struct task_struct*)get_free_page();
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if (!p)
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return -EAGAIN;
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task[nr] = p;
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__asm__ volatile ("cld");
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*p = *current; /* NOTE! this doesn't copy the supervisor stack */
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p->state = TASK_UNINTERRUPTIBLE;
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p->pid = last_pid;
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p->father = current->pid;
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p->counter = p->priority;
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p->signal = 0;
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p->alarm = 0;
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p->leader = 0; /* process leadership doesn't inherit */
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p->utime = p->stime = 0;
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p->cutime = p->cstime = 0;
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p->start_time = jiffies;
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p->tss.back_link = 0;
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p->tss.esp0 = PAGE_SIZE + (long)p;
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p->tss.ss0 = 0x10;
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p->tss.eip = eip;
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p->tss.eflags = eflags;
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p->tss.eax = 0;
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p->tss.ecx = ecx;
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p->tss.edx = edx;
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p->tss.ebx = ebx;
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p->tss.esp = esp;
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p->tss.ebp = ebp;
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p->tss.esi = esi;
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p->tss.edi = edi;
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p->tss.es = es & 0xffff;
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p->tss.cs = cs & 0xffff;
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p->tss.ss = ss & 0xffff;
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p->tss.ds = ds & 0xffff;
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p->tss.fs = fs & 0xffff;
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p->tss.gs = gs & 0xffff;
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p->tss.ldt = _LDT(nr);
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p->tss.trace_bitmap = 0x80000000;
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if (last_task_used_math == current)
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__asm__("clts ; fnsave %0"::"m" (p->tss.i387));
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if (copy_mem(nr, p)) {
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task[nr] = NULL;
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free_page((long)p);
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return -EAGAIN;
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}
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for (i = 0; i < NR_OPEN; i++)
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if (f = p->filp[i])
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f->f_count++;
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if (current->pwd)
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current->pwd->i_count++;
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if (current->root)
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current->root->i_count++;
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if (current->executable)
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current->executable->i_count++;
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set_tss_desc(gdt + (nr << 1) + FIRST_TSS_ENTRY, &(p->tss));
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set_ldt_desc(gdt + (nr << 1) + FIRST_LDT_ENTRY, &(p->ldt));
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p->state = TASK_RUNNING; /* do this last, just in case */
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return last_pid;
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}
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int find_empty_process(void)
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{
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int i;
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repeat:
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if ((++last_pid) < 0) last_pid = 1;
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for (i = 0; i < NR_TASKS; i++)
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if (task[i] && task[i]->pid == last_pid) goto repeat;
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for (i = 1; i < NR_TASKS; i++)
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if (!task[i])
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return i;
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return -EAGAIN;
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}
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int sys_pthread_attr_init(pthread_attr_t* attr) /* ϵͳ<CFB5><CDB3><EFBFBD><EFBFBD>pthread_attr_initʵ<74>ֺ<EFBFBD><D6BA><EFBFBD> */
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{
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if (!attr)
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{
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printk("Error:init pthread failed!\n");
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sys_exit(0);
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}
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/* <20><><EFBFBD><EFBFBD><EFBFBD>߳<EFBFBD>ջ<EFBFBD><D5BB><EFBFBD><EFBFBD>ʼ<EFBFBD><CABC>ַ<EFBFBD>ʹ<EFBFBD>С */
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attr->state = 0;
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attr->stackaddr = current->brk;
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attr->stacksize = PAGE_SIZE;
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return 0;
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}
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int thread_create(int nr, long ebp, long edi, long esi, long gs, long none,
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long ebx, long ecx, long edx,
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long fs, long es, long ds,
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long eip, long cs, long eflags, long esp, long ss)
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{
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struct task_struct* p;
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int i;
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struct file* f;
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/*******************************************/
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long func_addr = ecx; /* ecx<63>д洢<D0B4><E6B4A2><EFBFBD><EFBFBD><EFBFBD>̴߳<DFB3><CCB4><EFBFBD><EFBFBD><EFBFBD><EFBFBD>е<EFBFBD><D0B5><EFBFBD>ʼ<EFBFBD><CABC>ַ<EFBFBD><D6B7>edx<64>д洢<D0B4><E6B4A2><EFBFBD>Ǵ<EFBFBD><C7B4>ݸ<EFBFBD><DDB8>̵߳IJ<CCB5><C4B2><EFBFBD> */
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long func_arg = edx;
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/*******************************************/
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p = (struct task_struct*)get_free_page(); /*<2A><><EFBFBD><EFBFBD>һҳ<D2BB><D2B3><EFBFBD><EFBFBD>TCB*/
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if (!p)
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return -EAGAIN;
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task[nr] = p;
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*p = *current; /* NOTE! this doesn't copy the supervisor stack */
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/*******************************************/
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current->brk = current->brk + PAGE_SIZE; /*<2A><><EFBFBD><EFBFBD>ͬһ<CDAC><D2BB><EFBFBD><EFBFBD><EFBFBD>ڵ<EFBFBD><DAB5>̹߳<DFB3><CCB9><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ե<EFBFBD>ַ<EFBFBD>ռ䣬<D5BC><E4A3AC><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ҫ<EFBFBD><D2AA><EFBFBD><EFBFBD>TCB<43>ĵ<EFBFBD>ַ<EFBFBD>Լ<EFBFBD><D4BC><EFBFBD>ջ<EFBFBD><D5BB>ʼ<EFBFBD><CABC>ַ*/
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p->start_stack = current->brk;
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/*******************************************/
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p->state = TASK_UNINTERRUPTIBLE;
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p->pid = last_pid;
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p->father = current->pid;
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p->counter = p->priority;
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p->signal = 0;
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p->alarm = 0;
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p->leader = 0; /* process leadership doesn't inherit */
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p->utime = p->stime = 0;
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p->cutime = p->cstime = 0;
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p->start_time = jiffies;
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p->tss.back_link = 0;
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p->tss.esp0 = PAGE_SIZE + (long)p;
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p->tss.ss0 = 0x10;
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/*********************************************/
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p->tss.eip = func_addr; /* ecx<63>д洢<D0B4><E6B4A2><EFBFBD><EFBFBD><EFBFBD>̴߳<DFB3><CCB4><EFBFBD><EFBFBD><EFBFBD><EFBFBD>п<EFBFBD>ʼִ<CABC>еĵ<D0B5>ַ */
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/*********************************************/
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p->tss.eflags = eflags;
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p->tss.eax = 0;
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p->tss.ecx = ecx;
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p->tss.edx = edx;
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p->tss.ebx = ebx;
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/*********************************************/
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p->tss.esp = current->brk; /* ջ<><D5BB>ָ<EFBFBD><D6B8>Ӧ<EFBFBD>ȳ<EFBFBD>ʼ<EFBFBD><CABC>ΪΪ<CEAA>̶߳<DFB3>ջ<EFBFBD><D5BB><EFBFBD><EFBFBD>ʼ<EFBFBD><CABC>ַ */
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/*********************************************/
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p->tss.ebp = ebp;
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p->tss.esi = esi;
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p->tss.edi = edi;
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p->tss.es = es & 0xffff;
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p->tss.cs = cs & 0xffff;
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p->tss.ss = ss & 0xffff;
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p->tss.ds = ds & 0xffff;
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p->tss.fs = fs & 0xffff;
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p->tss.gs = gs & 0xffff;
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/*********************************************/
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p->tss.ldt = current->tss.ldt; /* <20><><EFBFBD><EFBFBD><EFBFBD>߳<EFBFBD><DFB3><EFBFBD>Ҫ<EFBFBD><D2AA><EFBFBD><EFBFBD><EFBFBD>߳<EFBFBD>ldt<64><74>ַ<EFBFBD><D6B7>Ϊ<EFBFBD><CEAA><EFBFBD><EFBFBD><EFBFBD>̵<EFBFBD>ldt<64><74>ַ */
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/*********************************************/
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p->tss.trace_bitmap = 0x80000000;
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if (last_task_used_math == current)
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__asm__("clts ; fnsave %0"::"m" (p->tss.i387));
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if (copy_mem(nr, p)) {
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task[nr] = NULL;
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free_page((long)p);
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return -EAGAIN;
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}
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/*********************************************/
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put_fs_long(func_arg, p->tss.esp); /* <20><>edx<64>д<EFBFBD>ŵIJ<C5B5><C4B2><EFBFBD><EFBFBD><EFBFBD><EFBFBD>浽<EFBFBD><E6B5BD><EFBFBD>̵߳Ķ<CCB5>ջ<EFBFBD><D5BB><EFBFBD><EFBFBD> */
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p->tss.esp -= 4; /* <20><><EFBFBD><EFBFBD><EFBFBD>˶<EFBFBD>ջָ<D5BB><D6B8><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ƶ<EFBFBD><C6B6>ĸ<EFBFBD><C4B8>ֽڣ<D6BD><DAA3>Դ<EFBFBD>ŷ<EFBFBD><C5B7>ص<EFBFBD>ַ */
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/*********************************************/
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for (i = 0; i < NR_OPEN; i++)
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if ((f = p->filp[i]))
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f->f_count++;
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if (current->pwd)
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current->pwd->i_count++;
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if (current->root)
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current->root->i_count++;
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if (current->executable)
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current->executable->i_count++;
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set_tss_desc(gdt + (nr << 1) + FIRST_TSS_ENTRY, &(p->tss));
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set_ldt_desc(gdt + (nr << 1) + FIRST_LDT_ENTRY, &(p->ldt));
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p->state = TASK_RUNNING;
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return p->pid;
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}
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