mirror of https://gitee.com/openkylin/linux.git
393 lines
9.3 KiB
C
393 lines
9.3 KiB
C
/*
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* linux/arch/arm26/kernel/process.c
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*
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* Copyright (C) 2003 Ian Molton - adapted for ARM26
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* Copyright (C) 1996-2000 Russell King - Converted to ARM.
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* Origional Copyright (C) 1995 Linus Torvalds
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <stdarg.h>
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/stddef.h>
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#include <linux/unistd.h>
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#include <linux/ptrace.h>
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#include <linux/slab.h>
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#include <linux/user.h>
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#include <linux/a.out.h>
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#include <linux/delay.h>
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#include <linux/reboot.h>
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#include <linux/interrupt.h>
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#include <linux/init.h>
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#include <asm/system.h>
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#include <asm/io.h>
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#include <asm/leds.h>
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#include <asm/processor.h>
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#include <asm/uaccess.h>
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extern const char *processor_modes[];
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extern void setup_mm_for_reboot(char mode);
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static volatile int hlt_counter;
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void disable_hlt(void)
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{
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hlt_counter++;
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}
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EXPORT_SYMBOL(disable_hlt);
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void enable_hlt(void)
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{
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hlt_counter--;
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}
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EXPORT_SYMBOL(enable_hlt);
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static int __init nohlt_setup(char *__unused)
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{
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hlt_counter = 1;
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return 1;
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}
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static int __init hlt_setup(char *__unused)
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{
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hlt_counter = 0;
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return 1;
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}
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__setup("nohlt", nohlt_setup);
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__setup("hlt", hlt_setup);
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/*
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* This is our default idle handler. We need to disable
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* interrupts here to ensure we don't miss a wakeup call.
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*/
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void cpu_idle(void)
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{
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/* endless idle loop with no priority at all */
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while (1) {
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while (!need_resched())
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cpu_relax();
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preempt_enable_no_resched();
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schedule();
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preempt_disable();
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}
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}
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static char reboot_mode = 'h';
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int __init reboot_setup(char *str)
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{
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reboot_mode = str[0];
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return 1;
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}
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__setup("reboot=", reboot_setup);
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/* ARM26 cant do these but we still need to define them. */
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void machine_halt(void)
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{
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}
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void machine_power_off(void)
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{
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}
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void machine_restart(char * __unused)
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{
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/*
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* Clean and disable cache, and turn off interrupts
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*/
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cpu_proc_fin();
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/*
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* Tell the mm system that we are going to reboot -
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* we may need it to insert some 1:1 mappings so that
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* soft boot works.
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*/
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setup_mm_for_reboot(reboot_mode);
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/*
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* copy branch instruction to reset location and call it
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*/
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*(unsigned long *)0 = *(unsigned long *)0x03800000;
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((void(*)(void))0)();
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/*
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* Whoops - the architecture was unable to reboot.
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* Tell the user! Should never happen...
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*/
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mdelay(1000);
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printk("Reboot failed -- System halted\n");
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while (1);
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}
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void show_regs(struct pt_regs * regs)
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{
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unsigned long flags;
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flags = condition_codes(regs);
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printk("pc : [<%08lx>] lr : [<%08lx>] %s\n"
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"sp : %08lx ip : %08lx fp : %08lx\n",
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instruction_pointer(regs),
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regs->ARM_lr, print_tainted(), regs->ARM_sp,
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regs->ARM_ip, regs->ARM_fp);
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printk("r10: %08lx r9 : %08lx r8 : %08lx\n",
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regs->ARM_r10, regs->ARM_r9,
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regs->ARM_r8);
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printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n",
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regs->ARM_r7, regs->ARM_r6,
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regs->ARM_r5, regs->ARM_r4);
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printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n",
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regs->ARM_r3, regs->ARM_r2,
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regs->ARM_r1, regs->ARM_r0);
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printk("Flags: %c%c%c%c",
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flags & PSR_N_BIT ? 'N' : 'n',
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flags & PSR_Z_BIT ? 'Z' : 'z',
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flags & PSR_C_BIT ? 'C' : 'c',
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flags & PSR_V_BIT ? 'V' : 'v');
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printk(" IRQs o%s FIQs o%s Mode %s Segment %s\n",
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interrupts_enabled(regs) ? "n" : "ff",
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fast_interrupts_enabled(regs) ? "n" : "ff",
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processor_modes[processor_mode(regs)],
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get_fs() == get_ds() ? "kernel" : "user");
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}
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void show_fpregs(struct user_fp *regs)
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{
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int i;
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for (i = 0; i < 8; i++) {
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unsigned long *p;
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char type;
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p = (unsigned long *)(regs->fpregs + i);
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switch (regs->ftype[i]) {
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case 1: type = 'f'; break;
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case 2: type = 'd'; break;
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case 3: type = 'e'; break;
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default: type = '?'; break;
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}
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if (regs->init_flag)
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type = '?';
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printk(" f%d(%c): %08lx %08lx %08lx%c",
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i, type, p[0], p[1], p[2], i & 1 ? '\n' : ' ');
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}
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printk("FPSR: %08lx FPCR: %08lx\n",
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(unsigned long)regs->fpsr,
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(unsigned long)regs->fpcr);
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}
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/*
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* Task structure and kernel stack allocation.
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*/
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static unsigned long *thread_info_head;
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static unsigned int nr_thread_info;
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extern unsigned long get_page_8k(int priority);
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extern void free_page_8k(unsigned long page);
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// FIXME - is this valid?
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#define EXTRA_TASK_STRUCT 0
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#define ll_alloc_task_struct() ((struct thread_info *)get_page_8k(GFP_KERNEL))
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#define ll_free_task_struct(p) free_page_8k((unsigned long)(p))
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//FIXME - do we use *task param below looks like we dont, which is ok?
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//FIXME - if EXTRA_TASK_STRUCT is zero we can optimise the below away permanently. *IF* its supposed to be zero.
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struct thread_info *alloc_thread_info(struct task_struct *task)
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{
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struct thread_info *thread = NULL;
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if (EXTRA_TASK_STRUCT) {
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unsigned long *p = thread_info_head;
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if (p) {
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thread_info_head = (unsigned long *)p[0];
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nr_thread_info -= 1;
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}
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thread = (struct thread_info *)p;
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}
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if (!thread)
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thread = ll_alloc_task_struct();
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#ifdef CONFIG_MAGIC_SYSRQ
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/*
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* The stack must be cleared if you want SYSRQ-T to
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* give sensible stack usage information
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*/
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if (thread) {
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char *p = (char *)thread;
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memzero(p+KERNEL_STACK_SIZE, KERNEL_STACK_SIZE);
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}
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#endif
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return thread;
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}
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void free_thread_info(struct thread_info *thread)
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{
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if (EXTRA_TASK_STRUCT && nr_thread_info < EXTRA_TASK_STRUCT) {
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unsigned long *p = (unsigned long *)thread;
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p[0] = (unsigned long)thread_info_head;
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thread_info_head = p;
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nr_thread_info += 1;
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} else
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ll_free_task_struct(thread);
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}
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/*
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* Free current thread data structures etc..
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*/
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void exit_thread(void)
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{
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}
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void flush_thread(void)
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{
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struct thread_info *thread = current_thread_info();
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struct task_struct *tsk = current;
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memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
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memset(&thread->fpstate, 0, sizeof(union fp_state));
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clear_used_math();
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}
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void release_thread(struct task_struct *dead_task)
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{
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}
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asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
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int
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copy_thread(int nr, unsigned long clone_flags, unsigned long stack_start,
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unsigned long unused, struct task_struct *p, struct pt_regs *regs)
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{
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struct thread_info *thread = task_thread_info(p);
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struct pt_regs *childregs = task_pt_regs(p);
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*childregs = *regs;
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childregs->ARM_r0 = 0;
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childregs->ARM_sp = stack_start;
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memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
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thread->cpu_context.sp = (unsigned long)childregs;
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thread->cpu_context.pc = (unsigned long)ret_from_fork | MODE_SVC26 | PSR_I_BIT;
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return 0;
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}
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/*
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* fill in the fpe structure for a core dump...
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*/
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int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
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{
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struct thread_info *thread = current_thread_info();
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int used_math = !!used_math();
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if (used_math)
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memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
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return used_math;
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}
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/*
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* fill in the user structure for a core dump..
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*/
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void dump_thread(struct pt_regs * regs, struct user * dump)
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{
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struct task_struct *tsk = current;
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dump->magic = CMAGIC;
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dump->start_code = tsk->mm->start_code;
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dump->start_stack = regs->ARM_sp & ~(PAGE_SIZE - 1);
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dump->u_tsize = (tsk->mm->end_code - tsk->mm->start_code) >> PAGE_SHIFT;
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dump->u_dsize = (tsk->mm->brk - tsk->mm->start_data + PAGE_SIZE - 1) >> PAGE_SHIFT;
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dump->u_ssize = 0;
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dump->u_debugreg[0] = tsk->thread.debug.bp[0].address;
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dump->u_debugreg[1] = tsk->thread.debug.bp[1].address;
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dump->u_debugreg[2] = tsk->thread.debug.bp[0].insn;
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dump->u_debugreg[3] = tsk->thread.debug.bp[1].insn;
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dump->u_debugreg[4] = tsk->thread.debug.nsaved;
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if (dump->start_stack < 0x04000000)
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dump->u_ssize = (0x04000000 - dump->start_stack) >> PAGE_SHIFT;
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dump->regs = *regs;
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dump->u_fpvalid = dump_fpu (regs, &dump->u_fp);
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}
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/*
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* Shuffle the argument into the correct register before calling the
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* thread function. r1 is the thread argument, r2 is the pointer to
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* the thread function, and r3 points to the exit function.
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* FIXME - make sure this is right - the older code used to zero fp
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* and cause the parent to call sys_exit (do_exit in this version)
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*/
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extern void kernel_thread_helper(void);
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asm( ".section .text\n"
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" .align\n"
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" .type kernel_thread_helper, #function\n"
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"kernel_thread_helper:\n"
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" mov r0, r1\n"
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" mov lr, r3\n"
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" mov pc, r2\n"
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" .size kernel_thread_helper, . - kernel_thread_helper\n"
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" .previous");
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/*
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* Create a kernel thread.
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*/
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pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
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{
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struct pt_regs regs;
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memset(®s, 0, sizeof(regs));
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regs.ARM_r1 = (unsigned long)arg;
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regs.ARM_r2 = (unsigned long)fn;
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regs.ARM_r3 = (unsigned long)do_exit;
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regs.ARM_pc = (unsigned long)kernel_thread_helper | MODE_SVC26;
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return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, ®s, 0, NULL, NULL);
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}
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EXPORT_SYMBOL(kernel_thread);
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unsigned long get_wchan(struct task_struct *p)
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{
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unsigned long fp, lr;
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unsigned long stack_page;
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int count = 0;
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if (!p || p == current || p->state == TASK_RUNNING)
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return 0;
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stack_page = 4096 + (unsigned long)p;
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fp = thread_saved_fp(p);
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do {
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if (fp < stack_page || fp > 4092+stack_page)
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return 0;
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lr = pc_pointer (((unsigned long *)fp)[-1]);
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if (!in_sched_functions(lr))
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return lr;
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fp = *(unsigned long *) (fp - 12);
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} while (count ++ < 16);
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return 0;
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}
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