arch/mips/kernel/process.c - linux - Git at Google

 /*
  * This file is subject to the terms and conditions of the GNU General Public
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
  *
  * Copyright (C) 1994 - 1999, 2000 by Ralf Baechle and others.
  * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
  * Copyright (C) 2004 Thiemo Seufer
  */
 #include <linux/config.h>
 #include <linux/errno.h>
 #include <linux/module.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/slab.h>
 #include <linux/mman.h>
 #include <linux/personality.h>
 #include <linux/sys.h>
 #include <linux/user.h>
 #include <linux/a.out.h>
 #include <linux/init.h>
 #include <linux/completion.h>

 #include <asm/bootinfo.h>
 #include <asm/cpu.h>
 #include <asm/fpu.h>
 #include <asm/pgtable.h>
 #include <asm/system.h>
 #include <asm/mipsregs.h>
 #include <asm/processor.h>
 #include <asm/uaccess.h>
 #include <asm/io.h>
 #include <asm/elf.h>
 #include <asm/isadep.h>
 #include <asm/inst.h>

 /*
  * We use this if we don't have any better idle routine..
  * (This to kill: kernel/platform.c.
  */
 void default_idle (void)
 {
 }

 /*
  * 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)
  */
 ATTRIB_NORET void cpu_idle(void)
 {
 	/* endless idle loop with no priority at all */
 	while (1) {
 		while (!need_resched())
 			if (cpu_wait)
 				(*cpu_wait)();
 		schedule();
 	}
 }

 asmlinkage void ret_from_fork(void);

 void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
 {
 	unsigned long status;

 	/* New thread loses kernel privileges. */
 	status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|KU_MASK);
 #ifdef CONFIG_64BIT
 	status &= ~ST0_FR;
 	status |= (current->thread.mflags & MF_32BIT_REGS) ? 0 : ST0_FR;
 #endif
 	status |= KU_USER;
 	regs->cp0_status = status;
 	clear_used_math();
 	lose_fpu();
 	regs->cp0_epc = pc;
 	regs->regs[29] = sp;
 	current_thread_info()->addr_limit = USER_DS;
 }

 void exit_thread(void)
 {
 }

 void flush_thread(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 thread_info *ti = p->thread_info;
 	struct pt_regs *childregs;
 	long childksp;

 	childksp = (unsigned long)ti + THREAD_SIZE - 32;

 	preempt_disable();

 	if (is_fpu_owner()) {
 		save_fp(p);
 	}

 	preempt_enable();

 	/* set up new TSS. */
 	childregs = (struct pt_regs *) childksp - 1;
 	*childregs = *regs;
 	childregs->regs[7] = 0;	/* Clear error flag */

 #if defined(CONFIG_BINFMT_IRIX)
 	if (current->personality != PER_LINUX) {
 		/* Under IRIX things are a little different. */
 		childregs->regs[3] = 1;
 		regs->regs[3] = 0;
 	}
 #endif
 	childregs->regs[2] = 0;	/* Child gets zero as return value */
 	regs->regs[2] = p->pid;

 	if (childregs->cp0_status & ST0_CU0) {
 		childregs->regs[28] = (unsigned long) ti;
 		childregs->regs[29] = childksp;
 		ti->addr_limit = KERNEL_DS;
 	} else {
 		childregs->regs[29] = usp;
 		ti->addr_limit = USER_DS;
 	}
 	p->thread.reg29 = (unsigned long) childregs;
 	p->thread.reg31 = (unsigned long) ret_from_fork;

 	/*
 	 * New tasks lose permission to use the fpu. This accelerates context
 	 * switching for most programs since they don't use the fpu.
 	 */
 	p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);
 	childregs->cp0_status &= ~(ST0_CU2|ST0_CU1);
 	clear_tsk_thread_flag(p, TIF_USEDFPU);

 	return 0;
 }

 /* Fill in the fpu structure for a core dump.. */
 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r)
 {
 	memcpy(r, &current->thread.fpu, sizeof(current->thread.fpu));

 	return 1;
 }

 void dump_regs(elf_greg_t *gp, struct pt_regs *regs)
 {
 	int i;

 	for (i = 0; i < EF_R0; i++)
 		gp[i] = 0;
 	gp[EF_R0] = 0;
 	for (i = 1; i <= 31; i++)
 		gp[EF_R0 + i] = regs->regs[i];
 	gp[EF_R26] = 0;
 	gp[EF_R27] = 0;
 	gp[EF_LO] = regs->lo;
 	gp[EF_HI] = regs->hi;
 	gp[EF_CP0_EPC] = regs->cp0_epc;
 	gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr;
 	gp[EF_CP0_STATUS] = regs->cp0_status;
 	gp[EF_CP0_CAUSE] = regs->cp0_cause;
 #ifdef EF_UNUSED0
 	gp[EF_UNUSED0] = 0;
 #endif
 }

 int dump_task_fpu (struct task_struct *t, elf_fpregset_t *fpr)
 {
 	memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu));

 	return 1;
 }

 /*
  * Create a kernel thread
  */
 ATTRIB_NORET void kernel_thread_helper(void *arg, int (*fn)(void *))
 {
 	do_exit(fn(arg));
 }

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

 	memset(&regs, 0, sizeof(regs));

 	regs.regs[4] = (unsigned long) arg;
 	regs.regs[5] = (unsigned long) fn;
 	regs.cp0_epc = (unsigned long) kernel_thread_helper;
 	regs.cp0_status = read_c0_status();
 #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
 	regs.cp0_status &= ~(ST0_KUP | ST0_IEC);
 	regs.cp0_status |= ST0_IEP;
 #else
 	regs.cp0_status |= ST0_EXL;
 #endif

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

 struct mips_frame_info {
 	int frame_offset;
 	int pc_offset;
 };
 static struct mips_frame_info schedule_frame;
 static struct mips_frame_info schedule_timeout_frame;
 static struct mips_frame_info sleep_on_frame;
 static struct mips_frame_info sleep_on_timeout_frame;
 static struct mips_frame_info wait_for_completion_frame;
 static int mips_frame_info_initialized;
 static int __init get_frame_info(struct mips_frame_info *info, void *func)
 {
 	int i;
 	union mips_instruction *ip = (union mips_instruction *)func;
 	info->pc_offset = -1;
 	info->frame_offset = -1;
 	for (i = 0; i < 128; i++, ip++) {
 		/* if jal, jalr, jr, stop. */
 		if (ip->j_format.opcode == jal_op ||
 		    (ip->r_format.opcode == spec_op &&
 		     (ip->r_format.func == jalr_op ||
 		      ip->r_format.func == jr_op)))
 			break;

 		if (
 #ifdef CONFIG_32BIT
 		    ip->i_format.opcode == sw_op &&
 #endif
 #ifdef CONFIG_64BIT
 		    ip->i_format.opcode == sd_op &&
 #endif
 		    ip->i_format.rs == 29)
 		{
 			/* sw / sd $ra, offset($sp) */
 			if (ip->i_format.rt == 31) {
 				if (info->pc_offset != -1)
 					break;
 				info->pc_offset =
 					ip->i_format.simmediate / sizeof(long);
 			}
 			/* sw / sd $s8, offset($sp) */
 			if (ip->i_format.rt == 30) {
 				if (info->frame_offset != -1)
 					break;
 				info->frame_offset =
 					ip->i_format.simmediate / sizeof(long);
 			}
 		}
 	}
 	if (info->pc_offset == -1 || info->frame_offset == -1) {
 		printk("Can't analyze prologue code at %p\n", func);
 		info->pc_offset = -1;
 		info->frame_offset = -1;
 		return -1;
 	}

 	return 0;
 }

 static int __init frame_info_init(void)
 {
 	mips_frame_info_initialized =
 		!get_frame_info(&schedule_frame, schedule) &&
 		!get_frame_info(&schedule_timeout_frame, schedule_timeout) &&
 		!get_frame_info(&sleep_on_frame, sleep_on) &&
 		!get_frame_info(&sleep_on_timeout_frame, sleep_on_timeout) &&
 		!get_frame_info(&wait_for_completion_frame, wait_for_completion);

 	return 0;
 }

 arch_initcall(frame_info_init);

 /*
  * Return saved PC of a blocked thread.
  */
 unsigned long thread_saved_pc(struct task_struct *tsk)
 {
 	struct thread_struct *t = &tsk->thread;

 	/* New born processes are a special case */
 	if (t->reg31 == (unsigned long) ret_from_fork)
 		return t->reg31;

 	if (schedule_frame.pc_offset < 0)
 		return 0;
 	return ((unsigned long *)t->reg29)[schedule_frame.pc_offset];
 }

 /* get_wchan - a maintenance nightmare^W^Wpain in the ass ...  */
 unsigned long get_wchan(struct task_struct *p)
 {
 	unsigned long frame, pc;

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

 	if (!mips_frame_info_initialized)
 		return 0;
 	pc = thread_saved_pc(p);
 	if (!in_sched_functions(pc))
 		goto out;

 	if (pc >= (unsigned long) sleep_on_timeout)
 		goto schedule_timeout_caller;
 	if (pc >= (unsigned long) sleep_on)
 		goto schedule_caller;
 	if (pc >= (unsigned long) interruptible_sleep_on_timeout)
 		goto schedule_timeout_caller;
 	if (pc >= (unsigned long)interruptible_sleep_on)
 		goto schedule_caller;
 	if (pc >= (unsigned long)wait_for_completion)
 		goto schedule_caller;
 	goto schedule_timeout_caller;

 schedule_caller:
 	frame = ((unsigned long *)p->thread.reg30)[schedule_frame.frame_offset];
 	if (pc >= (unsigned long) sleep_on)
 		pc = ((unsigned long *)frame)[sleep_on_frame.pc_offset];
 	else
 		pc = ((unsigned long *)frame)[wait_for_completion_frame.pc_offset];
 	goto out;

 schedule_timeout_caller:
 	/*
 	 * The schedule_timeout frame
 	 */
 	frame = ((unsigned long *)p->thread.reg30)[schedule_frame.frame_offset];

 	/*
 	 * frame now points to sleep_on_timeout's frame
 	 */
 	pc    = ((unsigned long *)frame)[schedule_timeout_frame.pc_offset];

 	if (in_sched_functions(pc)) {
 		/* schedule_timeout called by [interruptible_]sleep_on_timeout */
 		frame = ((unsigned long *)frame)[schedule_timeout_frame.frame_offset];
 		pc    = ((unsigned long *)frame)[sleep_on_timeout_frame.pc_offset];
 	}

 out:

 #ifdef CONFIG_64BIT
 	if (current->thread.mflags & MF_32BIT_REGS) /* Kludge for 32-bit ps  */
 		pc &= 0xffffffffUL;
 #endif

 	return pc;
 }

 EXPORT_SYMBOL(get_wchan);
	/*
	* This file is subject to the terms and conditions of the GNU General Public
	* License. See the file "COPYING" in the main directory of this archive
	* for more details.
	*
	* Copyright (C) 1994 - 1999, 2000 by Ralf Baechle and others.
	* Copyright (C) 1999, 2000 Silicon Graphics, Inc.
	* Copyright (C) 2004 Thiemo Seufer
	*/
	#include <linux/config.h>
	#include <linux/errno.h>
	#include <linux/module.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/slab.h>
	#include <linux/mman.h>
	#include <linux/personality.h>
	#include <linux/sys.h>
	#include <linux/user.h>
	#include <linux/a.out.h>
	#include <linux/init.h>
	#include <linux/completion.h>

	#include <asm/bootinfo.h>
	#include <asm/cpu.h>
	#include <asm/fpu.h>
	#include <asm/pgtable.h>
	#include <asm/system.h>
	#include <asm/mipsregs.h>
	#include <asm/processor.h>
	#include <asm/uaccess.h>
	#include <asm/io.h>
	#include <asm/elf.h>
	#include <asm/isadep.h>
	#include <asm/inst.h>

	/*
	* We use this if we don't have any better idle routine..
	* (This to kill: kernel/platform.c.
	*/
	void default_idle (void)
	{
	}

	/*
	* 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)
	*/
	ATTRIB_NORET void cpu_idle(void)
	{
	/* endless idle loop with no priority at all */
	while (1) {
	while (!need_resched())
	if (cpu_wait)
	(*cpu_wait)();
	schedule();
	}
	}

	asmlinkage void ret_from_fork(void);

	void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
	{
	unsigned long status;

	/* New thread loses kernel privileges. */
	status = regs->cp0_status & ~(ST0_CU0\|ST0_CU1\|KU_MASK);
	#ifdef CONFIG_64BIT
	status &= ~ST0_FR;
	status \|= (current->thread.mflags & MF_32BIT_REGS) ? 0 : ST0_FR;
	#endif
	status \|= KU_USER;
	regs->cp0_status = status;
	clear_used_math();
	lose_fpu();
	regs->cp0_epc = pc;
	regs->regs[29] = sp;
	current_thread_info()->addr_limit = USER_DS;
	}

	void exit_thread(void)
	{
	}

	void flush_thread(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 thread_info *ti = p->thread_info;
	struct pt_regs *childregs;
	long childksp;

	childksp = (unsigned long)ti + THREAD_SIZE - 32;

	preempt_disable();

	if (is_fpu_owner()) {
	save_fp(p);
	}

	preempt_enable();

	/* set up new TSS. */
	childregs = (struct pt_regs *) childksp - 1;
	childregs = regs;
	childregs->regs[7] = 0; /* Clear error flag */

	#if defined(CONFIG_BINFMT_IRIX)
	if (current->personality != PER_LINUX) {
	/* Under IRIX things are a little different. */
	childregs->regs[3] = 1;
	regs->regs[3] = 0;
	}
	#endif
	childregs->regs[2] = 0; /* Child gets zero as return value */
	regs->regs[2] = p->pid;

	if (childregs->cp0_status & ST0_CU0) {
	childregs->regs[28] = (unsigned long) ti;
	childregs->regs[29] = childksp;
	ti->addr_limit = KERNEL_DS;
	} else {
	childregs->regs[29] = usp;
	ti->addr_limit = USER_DS;
	}
	p->thread.reg29 = (unsigned long) childregs;
	p->thread.reg31 = (unsigned long) ret_from_fork;

	/*
	* New tasks lose permission to use the fpu. This accelerates context
	* switching for most programs since they don't use the fpu.
	*/
	p->thread.cp0_status = read_c0_status() & ~(ST0_CU2\|ST0_CU1);
	childregs->cp0_status &= ~(ST0_CU2\|ST0_CU1);
	clear_tsk_thread_flag(p, TIF_USEDFPU);

	return 0;
	}

	/* Fill in the fpu structure for a core dump.. */
	int dump_fpu(struct pt_regs regs, elf_fpregset_t r)
	{
	memcpy(r, &current->thread.fpu, sizeof(current->thread.fpu));

	return 1;
	}

	void dump_regs(elf_greg_t gp, struct pt_regs regs)
	{
	int i;

	for (i = 0; i < EF_R0; i++)
	gp[i] = 0;
	gp[EF_R0] = 0;
	for (i = 1; i <= 31; i++)
	gp[EF_R0 + i] = regs->regs[i];
	gp[EF_R26] = 0;
	gp[EF_R27] = 0;
	gp[EF_LO] = regs->lo;
	gp[EF_HI] = regs->hi;
	gp[EF_CP0_EPC] = regs->cp0_epc;
	gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr;
	gp[EF_CP0_STATUS] = regs->cp0_status;
	gp[EF_CP0_CAUSE] = regs->cp0_cause;
	#ifdef EF_UNUSED0
	gp[EF_UNUSED0] = 0;
	#endif
	}

	int dump_task_fpu (struct task_struct t, elf_fpregset_t fpr)
	{
	memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu));

	return 1;
	}

	/*
	* Create a kernel thread
	*/
	ATTRIB_NORET void kernel_thread_helper(void arg, int (fn)(void *))
	{
	do_exit(fn(arg));
	}

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

	memset(&regs, 0, sizeof(regs));

	regs.regs[4] = (unsigned long) arg;
	regs.regs[5] = (unsigned long) fn;
	regs.cp0_epc = (unsigned long) kernel_thread_helper;
	regs.cp0_status = read_c0_status();
	#if defined(CONFIG_CPU_R3000) \|\| defined(CONFIG_CPU_TX39XX)
	regs.cp0_status &= ~(ST0_KUP \| ST0_IEC);
	regs.cp0_status \|= ST0_IEP;
	#else
	regs.cp0_status \|= ST0_EXL;
	#endif

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

	struct mips_frame_info {
	int frame_offset;
	int pc_offset;
	};
	static struct mips_frame_info schedule_frame;
	static struct mips_frame_info schedule_timeout_frame;
	static struct mips_frame_info sleep_on_frame;
	static struct mips_frame_info sleep_on_timeout_frame;
	static struct mips_frame_info wait_for_completion_frame;
	static int mips_frame_info_initialized;
	static int __init get_frame_info(struct mips_frame_info info, void func)
	{
	int i;
	union mips_instruction ip = (union mips_instruction )func;
	info->pc_offset = -1;
	info->frame_offset = -1;
	for (i = 0; i < 128; i++, ip++) {
	/* if jal, jalr, jr, stop. */
	if (ip->j_format.opcode == jal_op \|\|
	(ip->r_format.opcode == spec_op &&
	(ip->r_format.func == jalr_op \|\|
	ip->r_format.func == jr_op)))
	break;

	if (
	#ifdef CONFIG_32BIT
	ip->i_format.opcode == sw_op &&
	#endif
	#ifdef CONFIG_64BIT
	ip->i_format.opcode == sd_op &&
	#endif
	ip->i_format.rs == 29)
	{
	/* sw / sd $ra, offset($sp) */
	if (ip->i_format.rt == 31) {
	if (info->pc_offset != -1)
	break;
	info->pc_offset =
	ip->i_format.simmediate / sizeof(long);
	}
	/* sw / sd $s8, offset($sp) */
	if (ip->i_format.rt == 30) {
	if (info->frame_offset != -1)
	break;
	info->frame_offset =
	ip->i_format.simmediate / sizeof(long);
	}
	}
	}
	if (info->pc_offset == -1 \|\| info->frame_offset == -1) {
	printk("Can't analyze prologue code at %p\n", func);
	info->pc_offset = -1;
	info->frame_offset = -1;
	return -1;
	}

	return 0;
	}

	static int __init frame_info_init(void)
	{
	mips_frame_info_initialized =
	!get_frame_info(&schedule_frame, schedule) &&
	!get_frame_info(&schedule_timeout_frame, schedule_timeout) &&
	!get_frame_info(&sleep_on_frame, sleep_on) &&
	!get_frame_info(&sleep_on_timeout_frame, sleep_on_timeout) &&
	!get_frame_info(&wait_for_completion_frame, wait_for_completion);

	return 0;
	}

	arch_initcall(frame_info_init);

	/*
	* Return saved PC of a blocked thread.
	*/
	unsigned long thread_saved_pc(struct task_struct *tsk)
	{
	struct thread_struct *t = &tsk->thread;

	/* New born processes are a special case */
	if (t->reg31 == (unsigned long) ret_from_fork)
	return t->reg31;

	if (schedule_frame.pc_offset < 0)
	return 0;
	return ((unsigned long *)t->reg29)[schedule_frame.pc_offset];
	}

	/* get_wchan - a maintenance nightmare^W^Wpain in the ass ... */
	unsigned long get_wchan(struct task_struct *p)
	{
	unsigned long frame, pc;

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

	if (!mips_frame_info_initialized)
	return 0;
	pc = thread_saved_pc(p);
	if (!in_sched_functions(pc))
	goto out;

	if (pc >= (unsigned long) sleep_on_timeout)
	goto schedule_timeout_caller;
	if (pc >= (unsigned long) sleep_on)
	goto schedule_caller;
	if (pc >= (unsigned long) interruptible_sleep_on_timeout)
	goto schedule_timeout_caller;
	if (pc >= (unsigned long)interruptible_sleep_on)
	goto schedule_caller;
	if (pc >= (unsigned long)wait_for_completion)
	goto schedule_caller;
	goto schedule_timeout_caller;

	schedule_caller:
	frame = ((unsigned long *)p->thread.reg30)[schedule_frame.frame_offset];
	if (pc >= (unsigned long) sleep_on)
	pc = ((unsigned long *)frame)[sleep_on_frame.pc_offset];
	else
	pc = ((unsigned long *)frame)[wait_for_completion_frame.pc_offset];
	goto out;

	schedule_timeout_caller:
	/*
	* The schedule_timeout frame
	*/
	frame = ((unsigned long *)p->thread.reg30)[schedule_frame.frame_offset];

	/*
	* frame now points to sleep_on_timeout's frame
	*/
	pc = ((unsigned long *)frame)[schedule_timeout_frame.pc_offset];

	if (in_sched_functions(pc)) {
	/* schedule_timeout called by [interruptible_]sleep_on_timeout */
	frame = ((unsigned long *)frame)[schedule_timeout_frame.frame_offset];
	pc = ((unsigned long *)frame)[sleep_on_timeout_frame.pc_offset];
	}

	out:

	#ifdef CONFIG_64BIT
	if (current->thread.mflags & MF_32BIT_REGS) /* Kludge for 32-bit ps */
	pc &= 0xffffffffUL;
	#endif

	return pc;
	}

	EXPORT_SYMBOL(get_wchan);