arch/blackfin/kernel/process.c - maze/linux - Git at Google

 /*
  * File:         arch/blackfin/kernel/process.c
  * Based on:
  * Author:
  *
  * Created:
  * Description:  Blackfin architecture-dependent process handling.
  *
  * Modified:
  *               Copyright 2004-2006 Analog Devices Inc.
  *
  * Bugs:         Enter bugs at http://blackfin.uclinux.org/
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, see the file COPYING, or write
  * to the Free Software Foundation, Inc.,
  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */

 #include <linux/module.h>
 #include <linux/smp_lock.h>
 #include <linux/unistd.h>
 #include <linux/user.h>
 #include <linux/uaccess.h>
 #include <linux/sched.h>
 #include <linux/tick.h>
 #include <linux/fs.h>
 #include <linux/err.h>

 #include <asm/blackfin.h>
 #include <asm/fixed_code.h>
 #include <asm/mem_map.h>

 asmlinkage void ret_from_fork(void);

 /* Points to the SDRAM backup memory for the stack that is currently in
  * L1 scratchpad memory.
  */
 void *current_l1_stack_save;

 /* The number of tasks currently using a L1 stack area.  The SRAM is
  * allocated/deallocated whenever this changes from/to zero.
  */
 int nr_l1stack_tasks;

 /* Start and length of the area in L1 scratchpad memory which we've allocated
  * for process stacks.
  */
 void *l1_stack_base;
 unsigned long l1_stack_len;

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

 void (*pm_power_off)(void) = NULL;
 EXPORT_SYMBOL(pm_power_off);

 /*
  * The idle loop on BFIN
  */
 #ifdef CONFIG_IDLE_L1
 static void default_idle(void)__attribute__((l1_text));
 void cpu_idle(void)__attribute__((l1_text));
 #endif

 /*
  * This is our default idle handler.  We need to disable
  * interrupts here to ensure we don't miss a wakeup call.
  */
 static void default_idle(void)
 {
 #ifdef CONFIG_IPIPE
 	ipipe_suspend_domain();
 #endif
 	local_irq_disable_hw();
 	if (!need_resched())
 		idle_with_irq_disabled();

 	local_irq_enable_hw();
 }

 /*
  * The idle thread.  We try to conserve power, while trying to keep
  * overall latency low.  The architecture specific idle is passed
  * a value to indicate the level of "idleness" of the system.
  */
 void cpu_idle(void)
 {
 	/* endless idle loop with no priority at all */
 	while (1) {
 		void (*idle)(void) = pm_idle;

 #ifdef CONFIG_HOTPLUG_CPU
 		if (cpu_is_offline(smp_processor_id()))
 			cpu_die();
 #endif
 		if (!idle)
 			idle = default_idle;
 		tick_nohz_stop_sched_tick(1);
 		while (!need_resched())
 			idle();
 		tick_nohz_restart_sched_tick();
 		preempt_enable_no_resched();
 		schedule();
 		preempt_disable();
 	}
 }

 /* Fill in the fpu structure for a core dump.  */

 int dump_fpu(struct pt_regs *regs, elf_fpregset_t * fpregs)
 {
 	return 1;
 }

 /*
  * This gets run with P1 containing the
  * function to call, and R1 containing
  * the "args".  Note P0 is clobbered on the way here.
  */
 void kernel_thread_helper(void);
 __asm__(".section .text\n"
 	".align 4\n"
 	"_kernel_thread_helper:\n\t"
 	"\tsp += -12;\n\t"
 	"\tr0 = r1;\n\t" "\tcall (p1);\n\t" "\tcall _do_exit;\n" ".previous");

 /*
  * Create a kernel thread.
  */
 pid_t kernel_thread(int (*fn) (void *), void *arg, unsigned long flags)
 {
 	struct pt_regs regs;

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

 	regs.r1 = (unsigned long)arg;
 	regs.p1 = (unsigned long)fn;
 	regs.pc = (unsigned long)kernel_thread_helper;
 	regs.orig_p0 = -1;
 	/* Set bit 2 to tell ret_from_fork we should be returning to kernel
 	   mode.  */
 	regs.ipend = 0x8002;
 	__asm__ __volatile__("%0 = syscfg;":"=da"(regs.syscfg):);
 	return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL,
 		       NULL);
 }
 EXPORT_SYMBOL(kernel_thread);

 void flush_thread(void)
 {
 }

 asmlinkage int bfin_vfork(struct pt_regs *regs)
 {
 	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL,
 		       NULL);
 }

 asmlinkage int bfin_clone(struct pt_regs *regs)
 {
 	unsigned long clone_flags;
 	unsigned long newsp;

 #ifdef __ARCH_SYNC_CORE_DCACHE
 	if (current->rt.nr_cpus_allowed == num_possible_cpus()) {
 		current->cpus_allowed = cpumask_of_cpu(smp_processor_id());
 		current->rt.nr_cpus_allowed = 1;
 	}
 #endif

 	/* syscall2 puts clone_flags in r0 and usp in r1 */
 	clone_flags = regs->r0;
 	newsp = regs->r1;
 	if (!newsp)
 		newsp = rdusp();
 	else
 		newsp -= 12;
 	return do_fork(clone_flags, newsp, regs, 0, NULL, NULL);
 }

 int
 copy_thread(unsigned long clone_flags,
 	    unsigned long usp, unsigned long topstk,
 	    struct task_struct *p, struct pt_regs *regs)
 {
 	struct pt_regs *childregs;

 	childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
 	*childregs = *regs;
 	childregs->r0 = 0;

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

 	return 0;
 }

 /*
  * sys_execve() executes a new program.
  */

 asmlinkage int sys_execve(char __user *name, char __user * __user *argv, char __user * __user *envp)
 {
 	int error;
 	char *filename;
 	struct pt_regs *regs = (struct pt_regs *)((&name) + 6);

 	lock_kernel();
 	filename = getname(name);
 	error = PTR_ERR(filename);
 	if (IS_ERR(filename))
 		goto out;
 	error = do_execve(filename, argv, envp, regs);
 	putname(filename);
  out:
 	unlock_kernel();
 	return error;
 }

 unsigned long get_wchan(struct task_struct *p)
 {
 	unsigned long fp, pc;
 	unsigned long stack_page;
 	int count = 0;
 	if (!p || p == current || p->state == TASK_RUNNING)
 		return 0;

 	stack_page = (unsigned long)p;
 	fp = p->thread.usp;
 	do {
 		if (fp < stack_page + sizeof(struct thread_info) ||
 		    fp >= 8184 + stack_page)
 			return 0;
 		pc = ((unsigned long *)fp)[1];
 		if (!in_sched_functions(pc))
 			return pc;
 		fp = *(unsigned long *)fp;
 	}
 	while (count++ < 16);
 	return 0;
 }

 void finish_atomic_sections (struct pt_regs *regs)
 {
 	int __user *up0 = (int __user *)regs->p0;

 	if (regs->pc < ATOMIC_SEQS_START || regs->pc >= ATOMIC_SEQS_END)
 		return;

 	switch (regs->pc) {
 	case ATOMIC_XCHG32 + 2:
 		put_user(regs->r1, up0);
 		regs->pc += 2;
 		break;

 	case ATOMIC_CAS32 + 2:
 	case ATOMIC_CAS32 + 4:
 		if (regs->r0 == regs->r1)
 			put_user(regs->r2, up0);
 		regs->pc = ATOMIC_CAS32 + 8;
 		break;
 	case ATOMIC_CAS32 + 6:
 		put_user(regs->r2, up0);
 		regs->pc += 2;
 		break;

 	case ATOMIC_ADD32 + 2:
 		regs->r0 = regs->r1 + regs->r0;
 		/* fall through */
 	case ATOMIC_ADD32 + 4:
 		put_user(regs->r0, up0);
 		regs->pc = ATOMIC_ADD32 + 6;
 		break;

 	case ATOMIC_SUB32 + 2:
 		regs->r0 = regs->r1 - regs->r0;
 		/* fall through */
 	case ATOMIC_SUB32 + 4:
 		put_user(regs->r0, up0);
 		regs->pc = ATOMIC_SUB32 + 6;
 		break;

 	case ATOMIC_IOR32 + 2:
 		regs->r0 = regs->r1 | regs->r0;
 		/* fall through */
 	case ATOMIC_IOR32 + 4:
 		put_user(regs->r0, up0);
 		regs->pc = ATOMIC_IOR32 + 6;
 		break;

 	case ATOMIC_AND32 + 2:
 		regs->r0 = regs->r1 & regs->r0;
 		/* fall through */
 	case ATOMIC_AND32 + 4:
 		put_user(regs->r0, up0);
 		regs->pc = ATOMIC_AND32 + 6;
 		break;

 	case ATOMIC_XOR32 + 2:
 		regs->r0 = regs->r1 ^ regs->r0;
 		/* fall through */
 	case ATOMIC_XOR32 + 4:
 		put_user(regs->r0, up0);
 		regs->pc = ATOMIC_XOR32 + 6;
 		break;
 	}
 }

 #if defined(CONFIG_ACCESS_CHECK)
 #ifdef CONFIG_ACCESS_OK_L1
 __attribute__((l1_text))
 #endif
 /* Return 1 if access to memory range is OK, 0 otherwise */
 int _access_ok(unsigned long addr, unsigned long size)
 {
 	if (size == 0)
 		return 1;
 	if (addr > (addr + size))
 		return 0;
 	if (segment_eq(get_fs(), KERNEL_DS))
 		return 1;
 #ifdef CONFIG_MTD_UCLINUX
 	if (addr >= memory_start && (addr + size) <= memory_end)
 		return 1;
 	if (addr >= memory_mtd_end && (addr + size) <= physical_mem_end)
 		return 1;

 #ifdef CONFIG_ROMFS_ON_MTD
 	/* For XIP, allow user space to use pointers within the ROMFS.  */
 	if (addr >= memory_mtd_start && (addr + size) <= memory_mtd_end)
 		return 1;
 #endif
 #else
 	if (addr >= memory_start && (addr + size) <= physical_mem_end)
 		return 1;
 #endif
 	if (addr >= (unsigned long)__init_begin &&
 	    addr + size <= (unsigned long)__init_end)
 		return 1;
 	if (addr >= get_l1_scratch_start()
 	    && addr + size <= get_l1_scratch_start() + L1_SCRATCH_LENGTH)
 		return 1;
 #if L1_CODE_LENGTH != 0
 	if (addr >= get_l1_code_start() + (_etext_l1 - _stext_l1)
 	    && addr + size <= get_l1_code_start() + L1_CODE_LENGTH)
 		return 1;
 #endif
 #if L1_DATA_A_LENGTH != 0
 	if (addr >= get_l1_data_a_start() + (_ebss_l1 - _sdata_l1)
 	    && addr + size <= get_l1_data_a_start() + L1_DATA_A_LENGTH)
 		return 1;
 #endif
 #if L1_DATA_B_LENGTH != 0
 	if (addr >= get_l1_data_b_start() + (_ebss_b_l1 - _sdata_b_l1)
 	    && addr + size <= get_l1_data_b_start() + L1_DATA_B_LENGTH)
 		return 1;
 #endif
 #if L2_LENGTH != 0
 	if (addr >= L2_START + (_ebss_l2 - _stext_l2)
 	    && addr + size <= L2_START + L2_LENGTH)
 		return 1;
 #endif
 	return 0;
 }
 EXPORT_SYMBOL(_access_ok);
 #endif /* CONFIG_ACCESS_CHECK */
	/*
	* File: arch/blackfin/kernel/process.c
	* Based on:
	* Author:
	*
	* Created:
	* Description: Blackfin architecture-dependent process handling.
	*
	* Modified:
	* Copyright 2004-2006 Analog Devices Inc.
	*
	* Bugs: Enter bugs at http://blackfin.uclinux.org/
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, see the file COPYING, or write
	* to the Free Software Foundation, Inc.,
	* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
	*/

	#include <linux/module.h>
	#include <linux/smp_lock.h>
	#include <linux/unistd.h>
	#include <linux/user.h>
	#include <linux/uaccess.h>
	#include <linux/sched.h>
	#include <linux/tick.h>
	#include <linux/fs.h>
	#include <linux/err.h>

	#include <asm/blackfin.h>
	#include <asm/fixed_code.h>
	#include <asm/mem_map.h>

	asmlinkage void ret_from_fork(void);

	/* Points to the SDRAM backup memory for the stack that is currently in
	* L1 scratchpad memory.
	*/
	void *current_l1_stack_save;

	/* The number of tasks currently using a L1 stack area. The SRAM is
	* allocated/deallocated whenever this changes from/to zero.
	*/
	int nr_l1stack_tasks;

	/* Start and length of the area in L1 scratchpad memory which we've allocated
	* for process stacks.
	*/
	void *l1_stack_base;
	unsigned long l1_stack_len;

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

	void (*pm_power_off)(void) = NULL;
	EXPORT_SYMBOL(pm_power_off);

	/*
	* The idle loop on BFIN
	*/
	#ifdef CONFIG_IDLE_L1
	static void default_idle(void)__attribute__((l1_text));
	void cpu_idle(void)__attribute__((l1_text));
	#endif

	/*
	* This is our default idle handler. We need to disable
	* interrupts here to ensure we don't miss a wakeup call.
	*/
	static void default_idle(void)
	{
	#ifdef CONFIG_IPIPE
	ipipe_suspend_domain();
	#endif
	local_irq_disable_hw();
	if (!need_resched())
	idle_with_irq_disabled();

	local_irq_enable_hw();
	}

	/*
	* The idle thread. We try to conserve power, while trying to keep
	* overall latency low. The architecture specific idle is passed
	* a value to indicate the level of "idleness" of the system.
	*/
	void cpu_idle(void)
	{
	/* endless idle loop with no priority at all */
	while (1) {
	void (*idle)(void) = pm_idle;

	#ifdef CONFIG_HOTPLUG_CPU
	if (cpu_is_offline(smp_processor_id()))
	cpu_die();
	#endif
	if (!idle)
	idle = default_idle;
	tick_nohz_stop_sched_tick(1);
	while (!need_resched())
	idle();
	tick_nohz_restart_sched_tick();
	preempt_enable_no_resched();
	schedule();
	preempt_disable();
	}
	}

	/* Fill in the fpu structure for a core dump. */

	int dump_fpu(struct pt_regs regs, elf_fpregset_t fpregs)
	{
	return 1;
	}

	/*
	* This gets run with P1 containing the
	* function to call, and R1 containing
	* the "args". Note P0 is clobbered on the way here.
	*/
	void kernel_thread_helper(void);
	__asm__(".section .text\n"
	".align 4\n"
	"_kernel_thread_helper:\n\t"
	"\tsp += -12;\n\t"
	"\tr0 = r1;\n\t" "\tcall (p1);\n\t" "\tcall _do_exit;\n" ".previous");

	/*
	* Create a kernel thread.
	*/
	pid_t kernel_thread(int (fn) (void ), void *arg, unsigned long flags)
	{
	struct pt_regs regs;

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

	regs.r1 = (unsigned long)arg;
	regs.p1 = (unsigned long)fn;
	regs.pc = (unsigned long)kernel_thread_helper;
	regs.orig_p0 = -1;
	/* Set bit 2 to tell ret_from_fork we should be returning to kernel
	mode. */
	regs.ipend = 0x8002;
	__asm__ __volatile__("%0 = syscfg;":"=da"(regs.syscfg):);
	return do_fork(flags \| CLONE_VM \| CLONE_UNTRACED, 0, &regs, 0, NULL,
	NULL);
	}
	EXPORT_SYMBOL(kernel_thread);

	void flush_thread(void)
	{
	}

	asmlinkage int bfin_vfork(struct pt_regs *regs)
	{
	return do_fork(CLONE_VFORK \| CLONE_VM \| SIGCHLD, rdusp(), regs, 0, NULL,
	NULL);
	}

	asmlinkage int bfin_clone(struct pt_regs *regs)
	{
	unsigned long clone_flags;
	unsigned long newsp;

	#ifdef __ARCH_SYNC_CORE_DCACHE
	if (current->rt.nr_cpus_allowed == num_possible_cpus()) {
	current->cpus_allowed = cpumask_of_cpu(smp_processor_id());
	current->rt.nr_cpus_allowed = 1;
	}
	#endif

	/* syscall2 puts clone_flags in r0 and usp in r1 */
	clone_flags = regs->r0;
	newsp = regs->r1;
	if (!newsp)
	newsp = rdusp();
	else
	newsp -= 12;
	return do_fork(clone_flags, newsp, regs, 0, NULL, NULL);
	}

	int
	copy_thread(unsigned long clone_flags,
	unsigned long usp, unsigned long topstk,
	struct task_struct p, struct pt_regs regs)
	{
	struct pt_regs *childregs;

	childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
	childregs = regs;
	childregs->r0 = 0;

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

	return 0;
	}

	/*
	* sys_execve() executes a new program.
	*/

	asmlinkage int sys_execve(char __user name, char __user __user argv, char __user __user *envp)
	{
	int error;
	char *filename;
	struct pt_regs regs = (struct pt_regs )((&name) + 6);

	lock_kernel();
	filename = getname(name);
	error = PTR_ERR(filename);
	if (IS_ERR(filename))
	goto out;
	error = do_execve(filename, argv, envp, regs);
	putname(filename);
	out:
	unlock_kernel();
	return error;
	}

	unsigned long get_wchan(struct task_struct *p)
	{
	unsigned long fp, pc;
	unsigned long stack_page;
	int count = 0;
	if (!p \|\| p == current \|\| p->state == TASK_RUNNING)
	return 0;

	stack_page = (unsigned long)p;
	fp = p->thread.usp;
	do {
	if (fp < stack_page + sizeof(struct thread_info) \|\|
	fp >= 8184 + stack_page)
	return 0;
	pc = ((unsigned long *)fp)[1];
	if (!in_sched_functions(pc))
	return pc;
	fp = (unsigned long )fp;
	}
	while (count++ < 16);
	return 0;
	}

	void finish_atomic_sections (struct pt_regs *regs)
	{
	int __user up0 = (int __user )regs->p0;

	if (regs->pc < ATOMIC_SEQS_START \|\| regs->pc >= ATOMIC_SEQS_END)
	return;

	switch (regs->pc) {
	case ATOMIC_XCHG32 + 2:
	put_user(regs->r1, up0);
	regs->pc += 2;
	break;

	case ATOMIC_CAS32 + 2:
	case ATOMIC_CAS32 + 4:
	if (regs->r0 == regs->r1)
	put_user(regs->r2, up0);
	regs->pc = ATOMIC_CAS32 + 8;
	break;
	case ATOMIC_CAS32 + 6:
	put_user(regs->r2, up0);
	regs->pc += 2;
	break;

	case ATOMIC_ADD32 + 2:
	regs->r0 = regs->r1 + regs->r0;
	/* fall through */
	case ATOMIC_ADD32 + 4:
	put_user(regs->r0, up0);
	regs->pc = ATOMIC_ADD32 + 6;
	break;

	case ATOMIC_SUB32 + 2:
	regs->r0 = regs->r1 - regs->r0;
	/* fall through */
	case ATOMIC_SUB32 + 4:
	put_user(regs->r0, up0);
	regs->pc = ATOMIC_SUB32 + 6;
	break;

	case ATOMIC_IOR32 + 2:
	regs->r0 = regs->r1 \| regs->r0;
	/* fall through */
	case ATOMIC_IOR32 + 4:
	put_user(regs->r0, up0);
	regs->pc = ATOMIC_IOR32 + 6;
	break;

	case ATOMIC_AND32 + 2:
	regs->r0 = regs->r1 & regs->r0;
	/* fall through */
	case ATOMIC_AND32 + 4:
	put_user(regs->r0, up0);
	regs->pc = ATOMIC_AND32 + 6;
	break;

	case ATOMIC_XOR32 + 2:
	regs->r0 = regs->r1 ^ regs->r0;
	/* fall through */
	case ATOMIC_XOR32 + 4:
	put_user(regs->r0, up0);
	regs->pc = ATOMIC_XOR32 + 6;
	break;
	}
	}

	#if defined(CONFIG_ACCESS_CHECK)
	#ifdef CONFIG_ACCESS_OK_L1
	__attribute__((l1_text))
	#endif
	/* Return 1 if access to memory range is OK, 0 otherwise */
	int _access_ok(unsigned long addr, unsigned long size)
	{
	if (size == 0)
	return 1;
	if (addr > (addr + size))
	return 0;
	if (segment_eq(get_fs(), KERNEL_DS))
	return 1;
	#ifdef CONFIG_MTD_UCLINUX
	if (addr >= memory_start && (addr + size) <= memory_end)
	return 1;
	if (addr >= memory_mtd_end && (addr + size) <= physical_mem_end)
	return 1;

	#ifdef CONFIG_ROMFS_ON_MTD
	/* For XIP, allow user space to use pointers within the ROMFS. */
	if (addr >= memory_mtd_start && (addr + size) <= memory_mtd_end)
	return 1;
	#endif
	#else
	if (addr >= memory_start && (addr + size) <= physical_mem_end)
	return 1;
	#endif
	if (addr >= (unsigned long)__init_begin &&
	addr + size <= (unsigned long)__init_end)
	return 1;
	if (addr >= get_l1_scratch_start()
	&& addr + size <= get_l1_scratch_start() + L1_SCRATCH_LENGTH)
	return 1;
	#if L1_CODE_LENGTH != 0
	if (addr >= get_l1_code_start() + (_etext_l1 - _stext_l1)
	&& addr + size <= get_l1_code_start() + L1_CODE_LENGTH)
	return 1;
	#endif
	#if L1_DATA_A_LENGTH != 0
	if (addr >= get_l1_data_a_start() + (_ebss_l1 - _sdata_l1)
	&& addr + size <= get_l1_data_a_start() + L1_DATA_A_LENGTH)
	return 1;
	#endif
	#if L1_DATA_B_LENGTH != 0
	if (addr >= get_l1_data_b_start() + (_ebss_b_l1 - _sdata_b_l1)
	&& addr + size <= get_l1_data_b_start() + L1_DATA_B_LENGTH)
	return 1;
	#endif
	#if L2_LENGTH != 0
	if (addr >= L2_START + (_ebss_l2 - _stext_l2)
	&& addr + size <= L2_START + L2_LENGTH)
	return 1;
	#endif
	return 0;
	}
	EXPORT_SYMBOL(_access_ok);
	#endif /* CONFIG_ACCESS_CHECK */