Merge git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
[wrt350n-kernel.git] / arch / um / kernel / process.c
blobdae4c3a62ce7f620d2d2c18a1e6f7e992e0af001
1 /*
2 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3 * Copyright 2003 PathScale, Inc.
4 * Licensed under the GPL
5 */
7 #include <linux/stddef.h>
8 #include <linux/err.h>
9 #include <linux/hardirq.h>
10 #include <linux/gfp.h>
11 #include <linux/mm.h>
12 #include <linux/personality.h>
13 #include <linux/proc_fs.h>
14 #include <linux/ptrace.h>
15 #include <linux/random.h>
16 #include <linux/sched.h>
17 #include <linux/tick.h>
18 #include <linux/threads.h>
19 #include <asm/current.h>
20 #include <asm/pgtable.h>
21 #include <asm/uaccess.h>
22 #include "as-layout.h"
23 #include "kern_util.h"
24 #include "os.h"
25 #include "skas.h"
26 #include "tlb.h"
29 * This is a per-cpu array. A processor only modifies its entry and it only
30 * cares about its entry, so it's OK if another processor is modifying its
31 * entry.
33 struct cpu_task cpu_tasks[NR_CPUS] = { [0 ... NR_CPUS - 1] = { -1, NULL } };
35 static inline int external_pid(void)
37 /* FIXME: Need to look up userspace_pid by cpu */
38 return userspace_pid[0];
41 int pid_to_processor_id(int pid)
43 int i;
45 for (i = 0; i < ncpus; i++) {
46 if (cpu_tasks[i].pid == pid)
47 return i;
49 return -1;
52 void free_stack(unsigned long stack, int order)
54 free_pages(stack, order);
57 unsigned long alloc_stack(int order, int atomic)
59 unsigned long page;
60 gfp_t flags = GFP_KERNEL;
62 if (atomic)
63 flags = GFP_ATOMIC;
64 page = __get_free_pages(flags, order);
66 return page;
69 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
71 int pid;
73 current->thread.request.u.thread.proc = fn;
74 current->thread.request.u.thread.arg = arg;
75 pid = do_fork(CLONE_VM | CLONE_UNTRACED | flags, 0,
76 &current->thread.regs, 0, NULL, NULL);
77 return pid;
80 static inline void set_current(struct task_struct *task)
82 cpu_tasks[task_thread_info(task)->cpu] = ((struct cpu_task)
83 { external_pid(), task });
86 extern void arch_switch_to(struct task_struct *to);
88 void *_switch_to(void *prev, void *next, void *last)
90 struct task_struct *from = prev;
91 struct task_struct *to = next;
93 to->thread.prev_sched = from;
94 set_current(to);
96 do {
97 current->thread.saved_task = NULL;
99 switch_threads(&from->thread.switch_buf,
100 &to->thread.switch_buf);
102 arch_switch_to(current);
104 if (current->thread.saved_task)
105 show_regs(&(current->thread.regs));
106 to = current->thread.saved_task;
107 from = current;
108 } while (current->thread.saved_task);
110 return current->thread.prev_sched;
114 void interrupt_end(void)
116 if (need_resched())
117 schedule();
118 if (test_tsk_thread_flag(current, TIF_SIGPENDING))
119 do_signal();
122 void exit_thread(void)
126 void *get_current(void)
128 return current;
131 <<<<<<< HEAD:arch/um/kernel/process.c
132 extern void schedule_tail(struct task_struct *prev);
134 =======
135 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:arch/um/kernel/process.c
137 * This is called magically, by its address being stuffed in a jmp_buf
138 * and being longjmp-d to.
140 void new_thread_handler(void)
142 int (*fn)(void *), n;
143 void *arg;
145 if (current->thread.prev_sched != NULL)
146 schedule_tail(current->thread.prev_sched);
147 current->thread.prev_sched = NULL;
149 fn = current->thread.request.u.thread.proc;
150 arg = current->thread.request.u.thread.arg;
153 * The return value is 1 if the kernel thread execs a process,
154 * 0 if it just exits
156 n = run_kernel_thread(fn, arg, &current->thread.exec_buf);
157 if (n == 1) {
158 /* Handle any immediate reschedules or signals */
159 interrupt_end();
160 userspace(&current->thread.regs.regs);
162 else do_exit(0);
165 /* Called magically, see new_thread_handler above */
166 void fork_handler(void)
168 force_flush_all();
170 schedule_tail(current->thread.prev_sched);
173 * XXX: if interrupt_end() calls schedule, this call to
174 * arch_switch_to isn't needed. We could want to apply this to
175 * improve performance. -bb
177 arch_switch_to(current);
179 current->thread.prev_sched = NULL;
181 /* Handle any immediate reschedules or signals */
182 interrupt_end();
184 userspace(&current->thread.regs.regs);
187 int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
188 unsigned long stack_top, struct task_struct * p,
189 struct pt_regs *regs)
191 void (*handler)(void);
192 int ret = 0;
194 p->thread = (struct thread_struct) INIT_THREAD;
196 if (current->thread.forking) {
197 memcpy(&p->thread.regs.regs, &regs->regs,
198 sizeof(p->thread.regs.regs));
199 REGS_SET_SYSCALL_RETURN(p->thread.regs.regs.gp, 0);
200 if (sp != 0)
201 REGS_SP(p->thread.regs.regs.gp) = sp;
203 handler = fork_handler;
205 arch_copy_thread(&current->thread.arch, &p->thread.arch);
207 else {
208 get_safe_registers(p->thread.regs.regs.gp);
209 p->thread.request.u.thread = current->thread.request.u.thread;
210 handler = new_thread_handler;
213 new_thread(task_stack_page(p), &p->thread.switch_buf, handler);
215 if (current->thread.forking) {
216 clear_flushed_tls(p);
219 * Set a new TLS for the child thread?
221 if (clone_flags & CLONE_SETTLS)
222 ret = arch_copy_tls(p);
225 return ret;
228 void initial_thread_cb(void (*proc)(void *), void *arg)
230 int save_kmalloc_ok = kmalloc_ok;
232 kmalloc_ok = 0;
233 initial_thread_cb_skas(proc, arg);
234 kmalloc_ok = save_kmalloc_ok;
237 void default_idle(void)
239 unsigned long long nsecs;
241 while (1) {
242 /* endless idle loop with no priority at all */
245 * although we are an idle CPU, we do not want to
246 * get into the scheduler unnecessarily.
248 if (need_resched())
249 schedule();
251 tick_nohz_stop_sched_tick();
252 nsecs = disable_timer();
253 idle_sleep(nsecs);
254 tick_nohz_restart_sched_tick();
258 void cpu_idle(void)
260 cpu_tasks[current_thread_info()->cpu].pid = os_getpid();
261 default_idle();
264 int __cant_sleep(void) {
265 return in_atomic() || irqs_disabled() || in_interrupt();
266 /* Is in_interrupt() really needed? */
269 int user_context(unsigned long sp)
271 unsigned long stack;
273 stack = sp & (PAGE_MASK << CONFIG_KERNEL_STACK_ORDER);
274 return stack != (unsigned long) current_thread_info();
277 extern exitcall_t __uml_exitcall_begin, __uml_exitcall_end;
279 void do_uml_exitcalls(void)
281 exitcall_t *call;
283 call = &__uml_exitcall_end;
284 while (--call >= &__uml_exitcall_begin)
285 (*call)();
288 char *uml_strdup(const char *string)
290 return kstrdup(string, GFP_KERNEL);
293 int copy_to_user_proc(void __user *to, void *from, int size)
295 return copy_to_user(to, from, size);
298 int copy_from_user_proc(void *to, void __user *from, int size)
300 return copy_from_user(to, from, size);
303 int clear_user_proc(void __user *buf, int size)
305 return clear_user(buf, size);
308 int strlen_user_proc(char __user *str)
310 return strlen_user(str);
313 int smp_sigio_handler(void)
315 #ifdef CONFIG_SMP
316 int cpu = current_thread_info()->cpu;
317 IPI_handler(cpu);
318 if (cpu != 0)
319 return 1;
320 #endif
321 return 0;
324 int cpu(void)
326 return current_thread_info()->cpu;
329 static atomic_t using_sysemu = ATOMIC_INIT(0);
330 int sysemu_supported;
332 void set_using_sysemu(int value)
334 if (value > sysemu_supported)
335 return;
336 atomic_set(&using_sysemu, value);
339 int get_using_sysemu(void)
341 return atomic_read(&using_sysemu);
344 static int proc_read_sysemu(char *buf, char **start, off_t offset, int size,int *eof, void *data)
346 if (snprintf(buf, size, "%d\n", get_using_sysemu()) < size)
347 /* No overflow */
348 *eof = 1;
350 return strlen(buf);
353 static int proc_write_sysemu(struct file *file,const char __user *buf, unsigned long count,void *data)
355 char tmp[2];
357 if (copy_from_user(tmp, buf, 1))
358 return -EFAULT;
360 if (tmp[0] >= '0' && tmp[0] <= '2')
361 set_using_sysemu(tmp[0] - '0');
362 /* We use the first char, but pretend to write everything */
363 return count;
366 int __init make_proc_sysemu(void)
368 struct proc_dir_entry *ent;
369 if (!sysemu_supported)
370 return 0;
372 ent = create_proc_entry("sysemu", 0600, &proc_root);
374 if (ent == NULL)
376 printk(KERN_WARNING "Failed to register /proc/sysemu\n");
377 return 0;
380 ent->read_proc = proc_read_sysemu;
381 ent->write_proc = proc_write_sysemu;
383 return 0;
386 late_initcall(make_proc_sysemu);
388 int singlestepping(void * t)
390 struct task_struct *task = t ? t : current;
392 if (!(task->ptrace & PT_DTRACE))
393 return 0;
395 if (task->thread.singlestep_syscall)
396 return 1;
398 return 2;
402 * Only x86 and x86_64 have an arch_align_stack().
403 * All other arches have "#define arch_align_stack(x) (x)"
404 * in their asm/system.h
405 * As this is included in UML from asm-um/system-generic.h,
406 * we can use it to behave as the subarch does.
408 #ifndef arch_align_stack
409 unsigned long arch_align_stack(unsigned long sp)
411 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
412 sp -= get_random_int() % 8192;
413 return sp & ~0xf;
415 #endif
417 unsigned long get_wchan(struct task_struct *p)
419 unsigned long stack_page, sp, ip;
420 bool seen_sched = 0;
422 if ((p == NULL) || (p == current) || (p->state == TASK_RUNNING))
423 return 0;
425 stack_page = (unsigned long) task_stack_page(p);
426 /* Bail if the process has no kernel stack for some reason */
427 if (stack_page == 0)
428 return 0;
430 sp = p->thread.switch_buf->JB_SP;
432 * Bail if the stack pointer is below the bottom of the kernel
433 * stack for some reason
435 if (sp < stack_page)
436 return 0;
438 while (sp < stack_page + THREAD_SIZE) {
439 ip = *((unsigned long *) sp);
440 if (in_sched_functions(ip))
441 /* Ignore everything until we're above the scheduler */
442 seen_sched = 1;
443 else if (kernel_text_address(ip) && seen_sched)
444 return ip;
446 sp += sizeof(unsigned long);
449 return 0;
452 int elf_core_copy_fpregs(struct task_struct *t, elf_fpregset_t *fpu)
454 int cpu = current_thread_info()->cpu;
456 return save_fp_registers(userspace_pid[cpu], (unsigned long *) fpu);