process.c

底层驱动开发

/*
 *  linux/arch/m32r/kernel/process.c
 *
 *  Copyright (c) 2001, 2002  Hiroyuki Kondo, Hirokazu Takata,
 *                            Hitoshi Yamamoto
 *  Taken from sh version.
 *    Copyright (C) 1995  Linus Torvalds
 *    SuperH version:  Copyright (C) 1999, 2000  Niibe Yutaka & Kaz Kojima
 */

#undef DEBUG_PROCESS
#ifdef DEBUG_PROCESS
#define DPRINTK(fmt, args...)  printk("%s:%d:%s: " fmt, __FILE__, __LINE__, \
  __FUNCTION__, ##args)
#else
#define DPRINTK(fmt, args...)
#endif

/*
 * This file handles the architecture-dependent parts of process handling..
 */

#include <linux/fs.h>
#include <linux/config.h>
#include <linux/module.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/slab.h>
#include <linux/hardirq.h>

#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/mmu_context.h>
#include <asm/elf.h>
#include <asm/m32r.h>

#include <linux/err.h>

static int hlt_counter=0;

/*
 * Return saved PC of a blocked thread.
 */
unsigned long thread_saved_pc(struct task_struct *tsk)
{
	return tsk->thread.lr;
}

/*
 * Powermanagement idle function, if any..
 */
void (*pm_idle)(void) = NULL;

void disable_hlt(void)
{
	hlt_counter++;
}

EXPORT_SYMBOL(disable_hlt);

void enable_hlt(void)
{
	hlt_counter--;
}

EXPORT_SYMBOL(enable_hlt);

/*
 * We use this is we don't have any better
 * idle routine..
 */
void default_idle(void)
{
	/* M32R_FIXME: Please use "cpu_sleep" mode.  */
	cpu_relax();
}

/*
 * On SMP it's slightly faster (but much more power-consuming!)
 * to poll the ->work.need_resched flag instead of waiting for the
 * cross-CPU IPI to arrive. Use this option with caution.
 */
static void poll_idle (void)
{
	/* M32R_FIXME */
	cpu_relax();
}

/*
 * The idle thread. There's no useful work to be
 * done, so just try to conserve power and have a
 * low exit latency (ie sit in a loop waiting for
 * somebody to say that they'd like to reschedule)
 */
void cpu_idle (void)
{
	/* endless idle loop with no priority at all */
	while (1) {
		while (!need_resched()) {
			void (*idle)(void) = pm_idle;

			if (!idle)
				idle = default_idle;

			idle();
		}
		schedule();
	}
}

void machine_restart(char *__unused)
{
	printk("Please push reset button!\n");
	while (1)
		cpu_relax();
}

void machine_halt(void)
{
	printk("Please push reset button!\n");
	while (1)
		cpu_relax();
}

void machine_power_off(void)
{
	/* M32R_FIXME */
}

static int __init idle_setup (char *str)
{
	if (!strncmp(str, "poll", 4)) {
		printk("using poll in idle threads.\n");
		pm_idle = poll_idle;
	} else if (!strncmp(str, "sleep", 4)) {
		printk("using sleep in idle threads.\n");
		pm_idle = default_idle;
	}

	return 1;
}

__setup("idle=", idle_setup);

void show_regs(struct pt_regs * regs)
{
	printk("\n");
	printk("BPC[%08lx]:PSW[%08lx]:LR [%08lx]:FP [%08lx]\n", \
	  regs->bpc, regs->psw, regs->lr, regs->fp);
	printk("BBPC[%08lx]:BBPSW[%08lx]:SPU[%08lx]:SPI[%08lx]\n", \
	  regs->bbpc, regs->bbpsw, regs->spu, regs->spi);
	printk("R0 [%08lx]:R1 [%08lx]:R2 [%08lx]:R3 [%08lx]\n", \
	  regs->r0, regs->r1, regs->r2, regs->r3);
	printk("R4 [%08lx]:R5 [%08lx]:R6 [%08lx]:R7 [%08lx]\n", \
	  regs->r4, regs->r5, regs->r6, regs->r7);
	printk("R8 [%08lx]:R9 [%08lx]:R10[%08lx]:R11[%08lx]\n", \
	  regs->r8, regs->r9, regs->r10, regs->r11);
	printk("R12[%08lx]\n", \
	  regs->r12);

#if defined(CONFIG_ISA_M32R2) && defined(CONFIG_ISA_DSP_LEVEL2)
	printk("ACC0H[%08lx]:ACC0L[%08lx]\n", \
	  regs->acc0h, regs->acc0l);
	printk("ACC1H[%08lx]:ACC1L[%08lx]\n", \
	  regs->acc1h, regs->acc1l);
#elif defined(CONFIG_ISA_M32R2) || defined(CONFIG_ISA_M32R)
	printk("ACCH[%08lx]:ACCL[%08lx]\n", \
	  regs->acch, regs->accl);
#else
#error unknown isa configuration
#endif
}

/*
 * Create a kernel thread
 */

/*
 * This is the mechanism for creating a new kernel thread.
 *
 * NOTE! Only a kernel-only process(ie the swapper or direct descendants
 * who haven't done an "execve()") should use this: it will work within
 * a system call from a "real" process, but the process memory space will
 * not be free'd until both the parent and the child have exited.
 */
static void kernel_thread_helper(void *nouse, int (*fn)(void *), void *arg)
{
	fn(arg);
	do_exit(-1);
}

int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
{
	struct pt_regs regs;

	memset(&regs, 0, sizeof (regs));
	regs.r1 = (unsigned long)fn;
	regs.r2 = (unsigned long)arg;

	regs.bpc = (unsigned long)kernel_thread_helper;

	regs.psw = M32R_PSW_BIE;

	/* Ok, create the new process. */
	return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL,
		NULL);
}

/*
 * Free current thread data structures etc..
 */
void exit_thread(void)
{
	/* Nothing to do. */
	DPRINTK("pid = %d\n", current->pid);
}

void flush_thread(void)
{
	DPRINTK("pid = %d\n", current->pid);
	memset(&current->thread.debug_trap, 0, sizeof(struct debug_trap));
}

void release_thread(struct task_struct *dead_task)
{
	/* do nothing */
	DPRINTK("pid = %d\n", dead_task->pid);
}

/* Fill in the fpu structure for a core dump.. */
int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
{
	return 0; /* Task didn't use the fpu at all. */
}

int copy_thread(int nr, unsigned long clone_flags, unsigned long spu,
	unsigned long unused, struct task_struct *tsk, struct pt_regs *regs)
{
	struct pt_regs *childregs;
	unsigned long sp = (unsigned long)tsk->thread_info + THREAD_SIZE;
	extern void ret_from_fork(void);

	/* Copy registers */
	sp -= sizeof (struct pt_regs);
	childregs = (struct pt_regs *)sp;
	*childregs = *regs;

	childregs->spu = spu;
	childregs->r0 = 0;	/* Child gets zero as return value */
	regs->r0 = tsk->pid;
	tsk->thread.sp = (unsigned long)childregs;
	tsk->thread.lr = (unsigned long)ret_from_fork;

	return 0;
}

/*
 * fill in the user structure for a core dump..
 */
void dump_thread(struct pt_regs * regs, struct user * dump)
{
	/* M32R_FIXME */
}

/*
 * Capture the user space registers if the task is not running (in user space)
 */
int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
{
	/* M32R_FIXME */
	return 1;
}

asmlinkage int sys_fork(unsigned long r0, unsigned long r1, unsigned long r2,
	unsigned long r3, unsigned long r4, unsigned long r5, unsigned long r6,
	struct pt_regs regs)
{
#ifdef CONFIG_MMU
	return do_fork(SIGCHLD, regs.spu, &regs, 0, NULL, NULL);
#else
	return -EINVAL;
#endif /* CONFIG_MMU */
}

asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
			 unsigned long parent_tidptr,
			 unsigned long child_tidptr,
			 unsigned long r4, unsigned long r5, unsigned long r6,
			 struct pt_regs regs)
{
	if (!newsp)
		newsp = regs.spu;

	return do_fork(clone_flags, newsp, &regs, 0,
		       (int __user *)parent_tidptr, (int __user *)child_tidptr);
}

/*
 * This is trivial, and on the face of it looks like it
 * could equally well be done in user mode.
 *
 * Not so, for quite unobvious reasons - register pressure.
 * In user mode vfork() cannot have a stack frame, and if
 * done by calling the "clone()" system call directly, you
 * do not have enough call-clobbered registers to hold all
 * the information you need.
 */
asmlinkage int sys_vfork(unsigned long r0, unsigned long r1, unsigned long r2,
	unsigned long r3, unsigned long r4, unsigned long r5, unsigned long r6,
	struct pt_regs regs)
{
	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs.spu, &regs, 0,
			NULL, NULL);
}

/*
 * sys_execve() executes a new program.
 */
asmlinkage int sys_execve(char __user *ufilename, char __user * __user *uargv,
			  char __user * __user *uenvp,
			  unsigned long r3, unsigned long r4, unsigned long r5,
			  unsigned long r6, struct pt_regs regs)
{
	int error;
	char *filename;

	filename = getname(ufilename);
	error = PTR_ERR(filename);
	if (IS_ERR(filename))
		goto out;

	error = do_execve(filename, uargv, uenvp, &regs);
	if (error == 0) {
		task_lock(current);
		current->ptrace &= ~PT_DTRACE;
		task_unlock(current);
	}
	putname(filename);
out:
	return error;
}

/*
 * These bracket the sleeping functions..
 */
#define first_sched	((unsigned long) scheduling_functions_start_here)
#define last_sched	((unsigned long) scheduling_functions_end_here)

unsigned long get_wchan(struct task_struct *p)
{
	/* M32R_FIXME */
	return (0);
}