arch/um/kernel/process.c

/*
 * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
 * Copyright 2003 PathScale, Inc.
 * Licensed under the GPL
 */

#include "linux/kernel.h"
#include "linux/sched.h"
#include "linux/interrupt.h"
#include "linux/string.h"
#include "linux/mm.h"
#include "linux/slab.h"
#include "linux/utsname.h"
#include "linux/fs.h"
#include "linux/utime.h"
#include "linux/smp_lock.h"
#include "linux/module.h"
#include "linux/init.h"
#include "linux/capability.h"
#include "linux/vmalloc.h"
#include "linux/spinlock.h"
#include "linux/proc_fs.h"
#include "linux/ptrace.h"
#include "linux/random.h"
#include "linux/personality.h"
#include "asm/unistd.h"
#include "asm/mman.h"
#include "asm/segment.h"
#include "asm/stat.h"
#include "asm/pgtable.h"
#include "asm/processor.h"
#include "asm/tlbflush.h"
#include "asm/uaccess.h"
#include "asm/user.h"
#include "kern_util.h"
#include "as-layout.h"
#include "kern.h"
#include "signal_kern.h"
#include "init.h"
#include "irq_user.h"
#include "mem_user.h"
#include "tlb.h"
#include "frame_kern.h"
#include "sigcontext.h"
#include "os.h"
#include "mode.h"
#include "mode_kern.h"
#include "choose-mode.h"

/* This is a per-cpu array.  A processor only modifies its entry and it only
 * cares about its entry, so it's OK if another processor is modifying its
 * entry.
 */
struct cpu_task cpu_tasks[NR_CPUS] = { [0 ... NR_CPUS - 1] = { -1, NULL } };

static inline int external_pid(struct task_struct *task)
{
	return CHOOSE_MODE_PROC(external_pid_tt, external_pid_skas, task);
}

int pid_to_processor_id(int pid)
{
	int i;

	for(i = 0; i < ncpus; i++){
		if(cpu_tasks[i].pid == pid)
			return i;
	}
	return -1;
}

void free_stack(unsigned long stack, int order)
{
	free_pages(stack, order);
}

unsigned long alloc_stack(int order, int atomic)
{
	unsigned long page;
	gfp_t flags = GFP_KERNEL;

	if (atomic)
		flags = GFP_ATOMIC;
	page = __get_free_pages(flags, order);
	if(page == 0)
		return 0;
	stack_protections(page);
	return page;
}

int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
{
	int pid;

	current->thread.request.u.thread.proc = fn;
	current->thread.request.u.thread.arg = arg;
	pid = do_fork(CLONE_VM | CLONE_UNTRACED | flags, 0,
		      &current->thread.regs, 0, NULL, NULL);
	return pid;
}

static inline void set_current(struct task_struct *task)
{
	cpu_tasks[task_thread_info(task)->cpu] = ((struct cpu_task)
		{ external_pid(task), task });
}

void *_switch_to(void *prev, void *next, void *last)
{
	struct task_struct *from = prev;
	struct task_struct *to= next;

	to->thread.prev_sched = from;
	set_current(to);

	do {
		current->thread.saved_task = NULL ;
		CHOOSE_MODE_PROC(switch_to_tt, switch_to_skas, prev, next);
		if(current->thread.saved_task)
			show_regs(&(current->thread.regs));
		next= current->thread.saved_task;
		prev= current;
	} while(current->thread.saved_task);

	return current->thread.prev_sched;

}

void interrupt_end(void)
{
	if(need_resched())
		schedule();
	if(test_tsk_thread_flag(current, TIF_SIGPENDING))
		do_signal();
}

void release_thread(struct task_struct *task)
{
	CHOOSE_MODE(release_thread_tt(task), release_thread_skas(task));
}

void exit_thread(void)
{
	unprotect_stack((unsigned long) current_thread);
}

void *get_current(void)
{
	return current;
}

int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
		unsigned long stack_top, struct task_struct * p,
		struct pt_regs *regs)
{
	int ret;

	p->thread = (struct thread_struct) INIT_THREAD;
	ret = CHOOSE_MODE_PROC(copy_thread_tt, copy_thread_skas, nr,
				clone_flags, sp, stack_top, p, regs);

	if (ret || !current->thread.forking)
		goto out;

	clear_flushed_tls(p);

	/*
	 * Set a new TLS for the child thread?
	 */
	if (clone_flags & CLONE_SETTLS)
		ret = arch_copy_tls(p);

out:
	return ret;
}

void initial_thread_cb(void (*proc)(void *), void *arg)
{
	int save_kmalloc_ok = kmalloc_ok;

	kmalloc_ok = 0;
	CHOOSE_MODE_PROC(initial_thread_cb_tt, initial_thread_cb_skas, proc,
			 arg);
	kmalloc_ok = save_kmalloc_ok;
}

#ifdef CONFIG_MODE_TT
unsigned long stack_sp(unsigned long page)
{
	return page + PAGE_SIZE - sizeof(void *);
}
#endif

void default_idle(void)
{
	CHOOSE_MODE(uml_idle_timer(), (void) 0);

	while(1){
		/* endless idle loop with no priority at all */

		/*
		 * although we are an idle CPU, we do not want to
		 * get into the scheduler unnecessarily.
		 */
		if(need_resched())
			schedule();

		idle_sleep(10);
	}
}

void cpu_idle(void)
{
	CHOOSE_MODE(init_idle_tt(), init_idle_skas());
}

void *um_virt_to_phys(struct task_struct *task, unsigned long addr,
		      pte_t *pte_out)
{
	pgd_t *pgd;
	pud_t *pud;
	pmd_t *pmd;
	pte_t *pte;
	pte_t ptent;

	if(task->mm == NULL)
		return ERR_PTR(-EINVAL);
	pgd = pgd_offset(task->mm, addr);
	if(!pgd_present(*pgd))
		return ERR_PTR(-EINVAL);

	pud = pud_offset(pgd, addr);
	if(!pud_present(*pud))
		return ERR_PTR(-EINVAL);

	pmd = pmd_offset(pud, addr);
	if(!pmd_present(*pmd))
		return ERR_PTR(-EINVAL);

	pte = pte_offset_kernel(pmd, addr);
	ptent = *pte;
	if(!pte_present(ptent))
		return ERR_PTR(-EINVAL);

	if(pte_out != NULL)
		*pte_out = ptent;
	return (void *) (pte_val(ptent) & PAGE_MASK) + (addr & ~PAGE_MASK);
}

char *current_cmd(void)
{
#if defined(CONFIG_SMP) || defined(CONFIG_HIGHMEM)
	return "(Unknown)";
#else
	void *addr = um_virt_to_phys(current, current->mm->arg_start, NULL);
	return IS_ERR(addr) ? "(Unknown)": __va((unsigned long) addr);
#endif
}

void dump_thread(struct pt_regs *regs, struct user *u)
{
}

int __cant_sleep(void) {
	return in_atomic() || irqs_disabled() || in_interrupt();
	/* Is in_interrupt() really needed? */
}

int user_context(unsigned long sp)
{
	unsigned long stack;

	stack = sp & (PAGE_MASK << CONFIG_KERNEL_STACK_ORDER);
	return stack != (unsigned long) current_thread;
}

extern exitcall_t __uml_exitcall_begin, __uml_exitcall_end;

void do_uml_exitcalls(void)
{
	exitcall_t *call;

	call = &__uml_exitcall_end;
	while (--call >= &__uml_exitcall_begin)
		(*call)();
}

char *uml_strdup(char *string)
{
	return kstrdup(string, GFP_KERNEL);
}

int copy_to_user_proc(void __user *to, void *from, int size)
{
	return copy_to_user(to, from, size);
}

int copy_from_user_proc(void *to, void __user *from, int size)
{
	return copy_from_user(to, from, size);
}

int clear_user_proc(void __user *buf, int size)
{
	return clear_user(buf, size);
}

int strlen_user_proc(char __user *str)
{
	return strlen_user(str);
}

int smp_sigio_handler(void)
{
#ifdef CONFIG_SMP
	int cpu = current_thread->cpu;
	IPI_handler(cpu);
	if(cpu != 0)
		return 1;
#endif
	return 0;
}

int cpu(void)
{
	return current_thread->cpu;
}

static atomic_t using_sysemu = ATOMIC_INIT(0);
int sysemu_supported;

void set_using_sysemu(int value)
{
	if (value > sysemu_supported)
		return;
	atomic_set(&using_sysemu, value);
}

int get_using_sysemu(void)
{
	return atomic_read(&using_sysemu);
}

static int proc_read_sysemu(char *buf, char **start, off_t offset, int size,int *eof, void *data)
{
	if (snprintf(buf, size, "%d\n", get_using_sysemu()) < size) /*No overflow*/
		*eof = 1;

	return strlen(buf);
}

static int proc_write_sysemu(struct file *file,const char __user *buf, unsigned long count,void *data)
{
	char tmp[2];

	if (copy_from_user(tmp, buf, 1))
		return -EFAULT;

	if (tmp[0] >= '0' && tmp[0] <= '2')
		set_using_sysemu(tmp[0] - '0');
	return count; /*We use the first char, but pretend to write everything*/
}

int __init make_proc_sysemu(void)
{
	struct proc_dir_entry *ent;
	if (!sysemu_supported)
		return 0;

	ent = create_proc_entry("sysemu", 0600, &proc_root);

	if (ent == NULL)
	{
		printk(KERN_WARNING "Failed to register /proc/sysemu\n");
		return 0;
	}

	ent->read_proc  = proc_read_sysemu;
	ent->write_proc = proc_write_sysemu;

	return 0;
}

late_initcall(make_proc_sysemu);

int singlestepping(void * t)
{
	struct task_struct *task = t ? t : current;

	if ( ! (task->ptrace & PT_DTRACE) )
		return(0);

	if (task->thread.singlestep_syscall)
		return(1);

	return 2;
}

/*
 * Only x86 and x86_64 have an arch_align_stack().
 * All other arches have "#define arch_align_stack(x) (x)"
 * in their asm/system.h
 * As this is included in UML from asm-um/system-generic.h,
 * we can use it to behave as the subarch does.
 */
#ifndef arch_align_stack
unsigned long arch_align_stack(unsigned long sp)
{
	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
		sp -= get_random_int() % 8192;
	return sp & ~0xf;
}
#endif