/* * 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 occurred 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"); if(0==(0x7fffffff & smp_process_available)) continue; while(0x80000000 & smp_process_available); cli(); while(set_bit(31,&smp_process_available)) while(test_bit(31,&smp_process_available)) { /* * Oops.. This is kind of important in some cases... */ if(clear_bit(smp_processor_id(), &smp_invalidate_needed)) local_flush_tlb(); } if (0==(0x7fffffff & smp_process_available)){ clear_bit(31,&smp_process_available); sti(); continue; } smp_process_available--; clear_bit(31,&smp_process_available); sti(); 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; /* * Forget coprocessor state.. */ #ifdef __SMP__ if (current->flags & PF_USEDFPU) { stts(); } #else if (last_task_used_math == current) { last_task_used_math = NULL; stts(); } #endif current->used_math = 0; current->flags &= ~PF_USEDFPU; } 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; }