linux/arch/um/kernel/process.c

454 lines
9.1 KiB
C

/*
* Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
* Copyright 2003 PathScale, Inc.
* Licensed under the GPL
*/
#include <linux/stddef.h>
#include <linux/err.h>
#include <linux/hardirq.h>
#include <linux/gfp.h>
#include <linux/mm.h>
#include <linux/personality.h>
#include <linux/proc_fs.h>
#include <linux/ptrace.h>
#include <linux/random.h>
#include <linux/sched.h>
#include <linux/tick.h>
#include <linux/threads.h>
#include <asm/current.h>
#include <asm/pgtable.h>
#include <asm/uaccess.h>
#include "as-layout.h"
#include "kern_util.h"
#include "os.h"
#include "skas.h"
#include "tlb.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(void)
{
/* FIXME: Need to look up userspace_pid by cpu */
return userspace_pid[0];
}
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);
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 });
}
extern void arch_switch_to(struct task_struct *to);
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;
switch_threads(&from->thread.switch_buf,
&to->thread.switch_buf);
arch_switch_to(current);
if (current->thread.saved_task)
show_regs(&(current->thread.regs));
to = current->thread.saved_task;
from = 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 exit_thread(void)
{
}
void *get_current(void)
{
return current;
}
/*
* This is called magically, by its address being stuffed in a jmp_buf
* and being longjmp-d to.
*/
void new_thread_handler(void)
{
int (*fn)(void *), n;
void *arg;
if (current->thread.prev_sched != NULL)
schedule_tail(current->thread.prev_sched);
current->thread.prev_sched = NULL;
fn = current->thread.request.u.thread.proc;
arg = current->thread.request.u.thread.arg;
/*
* The return value is 1 if the kernel thread execs a process,
* 0 if it just exits
*/
n = run_kernel_thread(fn, arg, &current->thread.exec_buf);
if (n == 1) {
/* Handle any immediate reschedules or signals */
interrupt_end();
userspace(&current->thread.regs.regs);
}
else do_exit(0);
}
/* Called magically, see new_thread_handler above */
void fork_handler(void)
{
force_flush_all();
schedule_tail(current->thread.prev_sched);
/*
* XXX: if interrupt_end() calls schedule, this call to
* arch_switch_to isn't needed. We could want to apply this to
* improve performance. -bb
*/
arch_switch_to(current);
current->thread.prev_sched = NULL;
/* Handle any immediate reschedules or signals */
interrupt_end();
userspace(&current->thread.regs.regs);
}
int copy_thread(unsigned long clone_flags, unsigned long sp,
unsigned long stack_top, struct task_struct * p,
struct pt_regs *regs)
{
void (*handler)(void);
int ret = 0;
p->thread = (struct thread_struct) INIT_THREAD;
if (current->thread.forking) {
memcpy(&p->thread.regs.regs, &regs->regs,
sizeof(p->thread.regs.regs));
REGS_SET_SYSCALL_RETURN(p->thread.regs.regs.gp, 0);
if (sp != 0)
REGS_SP(p->thread.regs.regs.gp) = sp;
handler = fork_handler;
arch_copy_thread(&current->thread.arch, &p->thread.arch);
}
else {
get_safe_registers(p->thread.regs.regs.gp);
p->thread.request.u.thread = current->thread.request.u.thread;
handler = new_thread_handler;
}
new_thread(task_stack_page(p), &p->thread.switch_buf, handler);
if (current->thread.forking) {
clear_flushed_tls(p);
/*
* Set a new TLS for the child thread?
*/
if (clone_flags & CLONE_SETTLS)
ret = arch_copy_tls(p);
}
return ret;
}
void initial_thread_cb(void (*proc)(void *), void *arg)
{
int save_kmalloc_ok = kmalloc_ok;
kmalloc_ok = 0;
initial_thread_cb_skas(proc, arg);
kmalloc_ok = save_kmalloc_ok;
}
void default_idle(void)
{
unsigned long long nsecs;
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();
tick_nohz_stop_sched_tick(1);
nsecs = disable_timer();
idle_sleep(nsecs);
tick_nohz_restart_sched_tick();
}
}
void cpu_idle(void)
{
cpu_tasks[current_thread_info()->cpu].pid = os_getpid();
default_idle();
}
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_info();
}
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(const 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_info()->cpu;
IPI_handler(cpu);
if (cpu != 0)
return 1;
#endif
return 0;
}
int cpu(void)
{
return current_thread_info()->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');
/* We use the first char, but pretend to write everything */
return count;
}
int __init make_proc_sysemu(void)
{
struct proc_dir_entry *ent;
if (!sysemu_supported)
return 0;
ent = create_proc_entry("sysemu", 0600, NULL);
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
unsigned long get_wchan(struct task_struct *p)
{
unsigned long stack_page, sp, ip;
bool seen_sched = 0;
if ((p == NULL) || (p == current) || (p->state == TASK_RUNNING))
return 0;
stack_page = (unsigned long) task_stack_page(p);
/* Bail if the process has no kernel stack for some reason */
if (stack_page == 0)
return 0;
sp = p->thread.switch_buf->JB_SP;
/*
* Bail if the stack pointer is below the bottom of the kernel
* stack for some reason
*/
if (sp < stack_page)
return 0;
while (sp < stack_page + THREAD_SIZE) {
ip = *((unsigned long *) sp);
if (in_sched_functions(ip))
/* Ignore everything until we're above the scheduler */
seen_sched = 1;
else if (kernel_text_address(ip) && seen_sched)
return ip;
sp += sizeof(unsigned long);
}
return 0;
}
int elf_core_copy_fpregs(struct task_struct *t, elf_fpregset_t *fpu)
{
int cpu = current_thread_info()->cpu;
return save_fp_registers(userspace_pid[cpu], (unsigned long *) fpu);
}