process.c

linux-2.4.29操作系统的源码

	al = (regs->regs[35]) & 0xffffffff;
	bh = (regs->regs[36]) >> 32;
	bl = (regs->regs[36]) & 0xffffffff;
	ch = (regs->regs[37]) >> 32;
	cl = (regs->regs[37]) & 0xffffffff;
	printk("R35 : %08Lx%08Lx R36 : %08Lx%08Lx R37 : %08Lx%08Lx\n",
	       ah, al, bh, bl, ch, cl);

	ah = (regs->regs[38]) >> 32;
	al = (regs->regs[38]) & 0xffffffff;
	bh = (regs->regs[39]) >> 32;
	bl = (regs->regs[39]) & 0xffffffff;
	ch = (regs->regs[40]) >> 32;
	cl = (regs->regs[40]) & 0xffffffff;
	printk("R38 : %08Lx%08Lx R39 : %08Lx%08Lx R40 : %08Lx%08Lx\n",
	       ah, al, bh, bl, ch, cl);

	ah = (regs->regs[41]) >> 32;
	al = (regs->regs[41]) & 0xffffffff;
	bh = (regs->regs[42]) >> 32;
	bl = (regs->regs[42]) & 0xffffffff;
	ch = (regs->regs[43]) >> 32;
	cl = (regs->regs[43]) & 0xffffffff;
	printk("R41 : %08Lx%08Lx R42 : %08Lx%08Lx R43 : %08Lx%08Lx\n",
	       ah, al, bh, bl, ch, cl);

	ah = (regs->regs[44]) >> 32;
	al = (regs->regs[44]) & 0xffffffff;
	bh = (regs->regs[45]) >> 32;
	bl = (regs->regs[45]) & 0xffffffff;
	ch = (regs->regs[46]) >> 32;
	cl = (regs->regs[46]) & 0xffffffff;
	printk("R44 : %08Lx%08Lx R45 : %08Lx%08Lx R46 : %08Lx%08Lx\n",
	       ah, al, bh, bl, ch, cl);

	ah = (regs->regs[47]) >> 32;
	al = (regs->regs[47]) & 0xffffffff;
	bh = (regs->regs[48]) >> 32;
	bl = (regs->regs[48]) & 0xffffffff;
	ch = (regs->regs[49]) >> 32;
	cl = (regs->regs[49]) & 0xffffffff;
	printk("R47 : %08Lx%08Lx R48 : %08Lx%08Lx R49 : %08Lx%08Lx\n",
	       ah, al, bh, bl, ch, cl);

	ah = (regs->regs[50]) >> 32;
	al = (regs->regs[50]) & 0xffffffff;
	bh = (regs->regs[51]) >> 32;
	bl = (regs->regs[51]) & 0xffffffff;
	ch = (regs->regs[52]) >> 32;
	cl = (regs->regs[52]) & 0xffffffff;
	printk("R50 : %08Lx%08Lx R51 : %08Lx%08Lx R52 : %08Lx%08Lx\n",
	       ah, al, bh, bl, ch, cl);

	ah = (regs->regs[53]) >> 32;
	al = (regs->regs[53]) & 0xffffffff;
	bh = (regs->regs[54]) >> 32;
	bl = (regs->regs[54]) & 0xffffffff;
	ch = (regs->regs[55]) >> 32;
	cl = (regs->regs[55]) & 0xffffffff;
	printk("R53 : %08Lx%08Lx R54 : %08Lx%08Lx R55 : %08Lx%08Lx\n",
	       ah, al, bh, bl, ch, cl);

	ah = (regs->regs[56]) >> 32;
	al = (regs->regs[56]) & 0xffffffff;
	bh = (regs->regs[57]) >> 32;
	bl = (regs->regs[57]) & 0xffffffff;
	ch = (regs->regs[58]) >> 32;
	cl = (regs->regs[58]) & 0xffffffff;
	printk("R56 : %08Lx%08Lx R57 : %08Lx%08Lx R58 : %08Lx%08Lx\n",
	       ah, al, bh, bl, ch, cl);

	ah = (regs->regs[59]) >> 32;
	al = (regs->regs[59]) & 0xffffffff;
	bh = (regs->regs[60]) >> 32;
	bl = (regs->regs[60]) & 0xffffffff;
	ch = (regs->regs[61]) >> 32;
	cl = (regs->regs[61]) & 0xffffffff;
	printk("R59 : %08Lx%08Lx R60 : %08Lx%08Lx R61 : %08Lx%08Lx\n",
	       ah, al, bh, bl, ch, cl);

	ah = (regs->regs[62]) >> 32;
	al = (regs->regs[62]) & 0xffffffff;
	bh = (regs->tregs[0]) >> 32;
	bl = (regs->tregs[0]) & 0xffffffff;
	ch = (regs->tregs[1]) >> 32;
	cl = (regs->tregs[1]) & 0xffffffff;
	printk("R62 : %08Lx%08Lx T0  : %08Lx%08Lx T1  : %08Lx%08Lx\n",
	       ah, al, bh, bl, ch, cl);

	ah = (regs->tregs[2]) >> 32;
	al = (regs->tregs[2]) & 0xffffffff;
	bh = (regs->tregs[3]) >> 32;
	bl = (regs->tregs[3]) & 0xffffffff;
	ch = (regs->tregs[4]) >> 32;
	cl = (regs->tregs[4]) & 0xffffffff;
	printk("T2  : %08Lx%08Lx T3  : %08Lx%08Lx T4  : %08Lx%08Lx\n",
	       ah, al, bh, bl, ch, cl);

	ah = (regs->tregs[5]) >> 32;
	al = (regs->tregs[5]) & 0xffffffff;
	bh = (regs->tregs[6]) >> 32;
	bl = (regs->tregs[6]) & 0xffffffff;
	ch = (regs->tregs[7]) >> 32;
	cl = (regs->tregs[7]) & 0xffffffff;
	printk("T5  : %08Lx%08Lx T6  : %08Lx%08Lx T7  : %08Lx%08Lx\n",
	       ah, al, bh, bl, ch, cl);

	/*
	 * If we're in kernel mode, dump the stack too..
	 */
	if (!user_mode(regs)) {
		extern void show_task(unsigned long *sp);
		unsigned long sp = regs->regs[15] & 0xffffffff;

		show_task((unsigned long *)sp);
	}
}

struct task_struct * alloc_task_struct(void)
{
	/* Get task descriptor pages */
	return (struct task_struct *)
		__get_free_pages(GFP_KERNEL, get_order(THREAD_SIZE));
}

void free_task_struct(struct task_struct *p)
{
	free_pages((unsigned long) p, get_order(THREAD_SIZE));
}

/*
 * 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.
 */
int arch_kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
{
	/* A bit less processor dependent than older sh ... */

	unsigned int reply;

static __inline__ _syscall2(int,clone,unsigned long,flags,unsigned long,newsp)
static __inline__ _syscall1(int,exit,int,ret)

	reply = clone(flags | CLONE_VM, 0);
	if (!reply) {
		/* Child */
		reply = exit(fn(arg));
	}

	return reply;
}

/*
 * Free current thread data structures etc..
 */
void exit_thread(void)
{
	/* See arch/sparc/kernel/process.c for the precedent for doing this -- RPC.
	
	   The SH-5 FPU save/restore approach relies on last_task_used_math
	   pointing to a live task_struct.  When another task tries to use the
	   FPU for the 1st time, the FPUDIS trap handling (see
	   arch/sh64/kernel/fpu.c) will save the existing FPU state to the
	   FP regs field within last_task_used_math before re-loading the new
	   task's FPU state (or initialising it if the FPU has been used
	   before).  So if last_task_used_math is stale, and its page has already been
	   re-allocated for another use, the consequences are rather grim. Unless we
	   null it here, there is no other path through which it would get safely
	   nulled. */

#ifndef CONFIG_NOFPU_SUPPORT
	if (last_task_used_math == current) {
		last_task_used_math = NULL;
	}
#endif
}

void flush_thread(void)
{

	/* As far as I can tell, this function isn't actually called from anywhere.
	   So why does it have a non-null body for most architectures?? -- RPC */
	/* Look closer, this is used in fs/exec.c by flush_old_exec() which is
	   used by binfmt_elf and friends to remove leftover traces of the
	   previously running executable. -- PFM */
#ifndef CONFIG_NOFPU_SUPPORT
	if (last_task_used_math == current) {
		last_task_used_math = NULL;
	}
#endif

	/* if we are a kernel thread, about to change to user thread,
         * update kreg 
         */
	if(current->thread.kregs==&fake_swapper_regs) {
          current->thread.kregs= 
             ((struct pt_regs *)(THREAD_SIZE + (unsigned long) current) - 1);
	}
}

void release_thread(struct task_struct *dead_task)
{
	/* do nothing */
}

/* Fill in the fpu structure for a core dump.. */
int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
{
#ifndef CONFIG_NOFPU_SUPPORT
	int fpvalid;
	struct task_struct *tsk = current;

	fpvalid = tsk->used_math;
	if (fpvalid) {
		if (current == last_task_used_math) {
			grab_fpu();
			fpsave(&tsk->thread.fpu.hard);
			release_fpu();
			last_task_used_math = 0;
			regs->sr |= SR_FD;
		}
		
		memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu));
	}

	return fpvalid;
#else
	return 0; /* Task didn't use the fpu at all. */
#endif
}

asmlinkage void ret_from_fork(void);

int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
		unsigned long unused,
		struct task_struct *p, struct pt_regs *regs)
{
	struct pt_regs *childregs;
	unsigned long long se;			/* Sign extension */
#ifndef CONFIG_NOFPU_SUPPORT
	if(last_task_used_math == current) {		
		grab_fpu();
		fpsave(&current->thread.fpu.hard);
		release_fpu();
		last_task_used_math = NULL;
		regs->sr |= SR_FD;
	}
#endif
	childregs = ((struct pt_regs *)(THREAD_SIZE + (unsigned long) p)) - 1;
	*childregs = *regs;

	if (user_mode(regs)) {
		childregs->regs[15] = usp;
		p->thread.kregs = childregs;
	} else {
		childregs->regs[15] = (unsigned long)p+THREAD_SIZE;
		p->thread.kregs = &fake_swapper_regs;
	}

	childregs->regs[9] = 0; /* Set return value for child */
	childregs->sr |= SR_FD; /* Invalidate FPU flag */

	p->thread.sp = (unsigned long) childregs;
	p->thread.pc = (unsigned long) ret_from_fork;

	/*
	 * Sign extend the edited stack.
         * Note that thread.pc and thread.pc will stay
	 * 32-bit wide and context switch must take care
	 * of NEFF sign extension.
	 */
      
	se = childregs->regs[15];
	se = (se & NEFF_SIGN) ? (se | NEFF_MASK) : se;
	childregs->regs[15] = se;

	return 0;
}

/*
 * 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[15] & ~(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;
	/* Debug registers will come here. */

	dump->regs = *regs;

	dump->u_fpvalid = dump_fpu(regs, &dump->fpu);
}

/*
 *	switch_to(x,y) should switch tasks from x to y.
 *
 */
struct task_struct * __switch_to(struct task_struct *prev, struct task_struct *next)
{
	/*
	 * Restore the kernel mode register
	 *   	KCR0 =  __c17
	 */
	asm volatile("putcon	%0, " __c17 "\n"
		     : /* no output */
		     :"r" (next));
	return prev;

}

asmlinkage int sys_fork(unsigned long r2, unsigned long r3,
			unsigned long r4, unsigned long r5,
			unsigned long r6, unsigned long r7,
			struct pt_regs *pregs)
{
	return do_fork(SIGCHLD, pregs->regs[15], pregs,0);
}

asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
			 unsigned long r4, unsigned long r5,
			 unsigned long r6, unsigned long r7,
			 struct pt_regs *pregs)
{
	if (!newsp)
		newsp = pregs->regs[15];
	return do_fork(clone_flags, newsp, pregs,0);
}

/*
 * 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 r2, unsigned long r3,
			 unsigned long r4, unsigned long r5,
			 unsigned long r6, unsigned long r7,
			 struct pt_regs *pregs)
{
	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, pregs->regs[15], pregs,0);
}

/*
 * sys_execve() executes a new program.
 */
asmlinkage int sys_execve(char *ufilename, char **uargv,
			  char **uenvp, unsigned long r5,
			  unsigned long r6, unsigned long r7,
			  struct pt_regs *pregs)
{
	int error;
	char *filename;

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

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

/*
 * These bracket the sleeping functions..
 */
extern void scheduling_functions_start_here(void);
extern void scheduling_functions_end_here(void);
extern void interruptible_sleep_on(wait_queue_head_t *q);

#define first_sched	((unsigned long) scheduling_functions_start_here)
#define mid_sched	((unsigned long) interruptible_sleep_on)
#define last_sched	((unsigned long) scheduling_functions_end_here)

unsigned long get_wchan(struct task_struct *p)
{
	unsigned long schedule_frame;
	unsigned long pc;

	if (!p || p == current || p->state == TASK_RUNNING)
		return 0;

	/*
	 * The same comment as on the Alpha applies here, too ...
	 */
	pc = thread_saved_pc(&p->thread);

	if (pc >= first_sched && pc < last_sched) {

		schedule_frame = (long) p->thread.sp;

		/* Should we unwind schedule_timeout() ? */
		if (pc < mid_sched)
			/* according to disasm:
			**     48 bytes in case of RH toolchain
		        */
			schedule_frame += 48;
			
		/*
		** Unwind schedule(). According to disasm:
		**    72 bytes in case of RH toolchain
		** plus 304 bytes of switch_to additional frame.
		*/
		schedule_frame += 72 + 304;

#ifdef CS_SAVE_ALL
		schedule_frame += 256;
#endif
		/*
		 * schedule_frame now according to SLEEP_ON_VAR.
	 	 * Bad thing is that we have no trace of the waiting
		 * address (the classical WCHAN). SLEEP_ON_VAR should
		 * have saved q. From the linked list only we can't get
		 * the object and first parameter is not saved on stack
		 * by the ABI. The best we can tell is who called the
		 * *sleep_on* by returning LINK, which is saved at
		 * offset 64 on all flavours.
		 */
		return (unsigned long)((unsigned long *)schedule_frame)[16];
	}
	return pc;
}

/* Provide a /proc/asids file that lists out the
   ASIDs currently associated with the processes.  (If the DM.PC register is
   examined through the debug link, this shows ASID + PC.  To make use of this,
   the PID->ASID relationship needs to be known.  This is primarily for
   debugging.)
   */

#if defined(CONFIG_SH64_PROC_ASIDS)
#include <linux/init.h>
#include <linux/proc_fs.h>

static int
asids_proc_info(char *buf, char **start, off_t fpos, int length, int *eof, void *data)
{
	int len=0;
	struct task_struct *p;
	read_lock(&tasklist_lock);
	for_each_task(p) {
		int pid = p->pid;
		struct mm_struct *mm;
		if (!pid) continue;
		mm = p->mm;
		if (mm) {
			unsigned long asid, context;
			context = mm->context;
			asid = (context & 0xff);
			len += sprintf(buf+len, "%5d : %02x\n", pid, asid);
		} else {
			len += sprintf(buf+len, "%5d : (none)\n", pid);
		}
	}
	read_unlock(&tasklist_lock);
	*eof = 1;
	return len;
}

static int __init register_proc_asids(void)
{
  create_proc_read_entry("asids", 0, NULL, asids_proc_info, NULL);
  return 0;
}

__initcall(register_proc_asids);
#endif