2 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3 * Copyright 2003 PathScale, Inc.
4 * Licensed under the GPL
7 #include "linux/stddef.h"
9 #include "linux/hardirq.h"
11 #include "linux/personality.h"
12 #include "linux/proc_fs.h"
13 #include "linux/ptrace.h"
14 #include "linux/random.h"
15 #include "linux/sched.h"
16 #include "linux/tick.h"
17 #include "linux/threads.h"
18 #include "asm/pgtable.h"
19 #include "asm/uaccess.h"
20 #include "as-layout.h"
21 #include "kern_util.h"
27 * This is a per-cpu array. A processor only modifies its entry and it only
28 * cares about its entry, so it's OK if another processor is modifying its
31 struct cpu_task cpu_tasks[NR_CPUS] = { [0 ... NR_CPUS - 1] = { -1, NULL } };
33 static inline int external_pid(struct task_struct *task)
35 /* FIXME: Need to look up userspace_pid by cpu */
36 return userspace_pid[0];
39 int pid_to_processor_id(int pid)
43 for(i = 0; i < ncpus; i++) {
44 if (cpu_tasks[i].pid == pid)
50 void free_stack(unsigned long stack, int order)
52 free_pages(stack, order);
55 unsigned long alloc_stack(int order, int atomic)
58 gfp_t flags = GFP_KERNEL;
62 page = __get_free_pages(flags, order);
69 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
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 ¤t->thread.regs, 0, NULL, NULL);
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), task });
86 extern void arch_switch_to(struct task_struct *from, 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;
97 current->thread.saved_task = NULL;
99 switch_threads(&from->thread.switch_buf,
100 &to->thread.switch_buf);
102 arch_switch_to(current->thread.prev_sched, current);
104 if (current->thread.saved_task)
105 show_regs(&(current->thread.regs));
106 next= current->thread.saved_task;
108 } while(current->thread.saved_task);
110 return current->thread.prev_sched;
114 void interrupt_end(void)
118 if (test_tsk_thread_flag(current, TIF_SIGPENDING))
122 void exit_thread(void)
126 void *get_current(void)
131 extern void schedule_tail(struct task_struct *prev);
134 * This is called magically, by its address being stuffed in a jmp_buf
135 * and being longjmp-d to.
137 void new_thread_handler(void)
139 int (*fn)(void *), n;
142 if (current->thread.prev_sched != NULL)
143 schedule_tail(current->thread.prev_sched);
144 current->thread.prev_sched = NULL;
146 fn = current->thread.request.u.thread.proc;
147 arg = current->thread.request.u.thread.arg;
150 * The return value is 1 if the kernel thread execs a process,
153 n = run_kernel_thread(fn, arg, ¤t->thread.exec_buf);
155 /* Handle any immediate reschedules or signals */
157 userspace(¤t->thread.regs.regs);
162 /* Called magically, see new_thread_handler above */
163 void fork_handler(void)
166 if (current->thread.prev_sched == NULL)
169 schedule_tail(current->thread.prev_sched);
172 * XXX: if interrupt_end() calls schedule, this call to
173 * arch_switch_to isn't needed. We could want to apply this to
174 * improve performance. -bb
176 arch_switch_to(current->thread.prev_sched, current);
178 current->thread.prev_sched = NULL;
180 /* Handle any immediate reschedules or signals */
183 userspace(¤t->thread.regs.regs);
186 int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
187 unsigned long stack_top, struct task_struct * p,
188 struct pt_regs *regs)
190 void (*handler)(void);
193 p->thread = (struct thread_struct) INIT_THREAD;
195 if (current->thread.forking) {
196 memcpy(&p->thread.regs.regs, ®s->regs,
197 sizeof(p->thread.regs.regs));
198 REGS_SET_SYSCALL_RETURN(p->thread.regs.regs.gp, 0);
200 REGS_SP(p->thread.regs.regs.gp) = sp;
202 handler = fork_handler;
204 arch_copy_thread(¤t->thread.arch, &p->thread.arch);
207 init_thread_registers(&p->thread.regs.regs);
208 p->thread.request.u.thread = current->thread.request.u.thread;
209 handler = new_thread_handler;
212 new_thread(task_stack_page(p), &p->thread.switch_buf, handler);
214 if (current->thread.forking) {
215 clear_flushed_tls(p);
218 * Set a new TLS for the child thread?
220 if (clone_flags & CLONE_SETTLS)
221 ret = arch_copy_tls(p);
227 void initial_thread_cb(void (*proc)(void *), void *arg)
229 int save_kmalloc_ok = kmalloc_ok;
232 initial_thread_cb_skas(proc, arg);
233 kmalloc_ok = save_kmalloc_ok;
236 void default_idle(void)
238 unsigned long long nsecs;
241 /* endless idle loop with no priority at all */
244 * although we are an idle CPU, we do not want to
245 * get into the scheduler unnecessarily.
250 tick_nohz_stop_sched_tick();
251 nsecs = disable_timer();
253 tick_nohz_restart_sched_tick();
259 cpu_tasks[current_thread->cpu].pid = os_getpid();
263 void *um_virt_to_phys(struct task_struct *task, unsigned long addr,
272 if (task->mm == NULL)
273 return ERR_PTR(-EINVAL);
274 pgd = pgd_offset(task->mm, addr);
275 if (!pgd_present(*pgd))
276 return ERR_PTR(-EINVAL);
278 pud = pud_offset(pgd, addr);
279 if (!pud_present(*pud))
280 return ERR_PTR(-EINVAL);
282 pmd = pmd_offset(pud, addr);
283 if (!pmd_present(*pmd))
284 return ERR_PTR(-EINVAL);
286 pte = pte_offset_kernel(pmd, addr);
288 if (!pte_present(ptent))
289 return ERR_PTR(-EINVAL);
293 return (void *) (pte_val(ptent) & PAGE_MASK) + (addr & ~PAGE_MASK);
296 char *current_cmd(void)
298 #if defined(CONFIG_SMP) || defined(CONFIG_HIGHMEM)
301 void *addr = um_virt_to_phys(current, current->mm->arg_start, NULL);
302 return IS_ERR(addr) ? "(Unknown)": __va((unsigned long) addr);
306 void dump_thread(struct pt_regs *regs, struct user *u)
310 int __cant_sleep(void) {
311 return in_atomic() || irqs_disabled() || in_interrupt();
312 /* Is in_interrupt() really needed? */
315 int user_context(unsigned long sp)
319 stack = sp & (PAGE_MASK << CONFIG_KERNEL_STACK_ORDER);
320 return stack != (unsigned long) current_thread;
323 extern exitcall_t __uml_exitcall_begin, __uml_exitcall_end;
325 void do_uml_exitcalls(void)
329 call = &__uml_exitcall_end;
330 while (--call >= &__uml_exitcall_begin)
334 char *uml_strdup(char *string)
336 return kstrdup(string, GFP_KERNEL);
339 int copy_to_user_proc(void __user *to, void *from, int size)
341 return copy_to_user(to, from, size);
344 int copy_from_user_proc(void *to, void __user *from, int size)
346 return copy_from_user(to, from, size);
349 int clear_user_proc(void __user *buf, int size)
351 return clear_user(buf, size);
354 int strlen_user_proc(char __user *str)
356 return strlen_user(str);
359 int smp_sigio_handler(void)
362 int cpu = current_thread->cpu;
372 return current_thread->cpu;
375 static atomic_t using_sysemu = ATOMIC_INIT(0);
376 int sysemu_supported;
378 void set_using_sysemu(int value)
380 if (value > sysemu_supported)
382 atomic_set(&using_sysemu, value);
385 int get_using_sysemu(void)
387 return atomic_read(&using_sysemu);
390 static int proc_read_sysemu(char *buf, char **start, off_t offset, int size,int *eof, void *data)
392 if (snprintf(buf, size, "%d\n", get_using_sysemu()) < size)
399 static int proc_write_sysemu(struct file *file,const char __user *buf, unsigned long count,void *data)
403 if (copy_from_user(tmp, buf, 1))
406 if (tmp[0] >= '0' && tmp[0] <= '2')
407 set_using_sysemu(tmp[0] - '0');
408 /* We use the first char, but pretend to write everything */
412 int __init make_proc_sysemu(void)
414 struct proc_dir_entry *ent;
415 if (!sysemu_supported)
418 ent = create_proc_entry("sysemu", 0600, &proc_root);
422 printk(KERN_WARNING "Failed to register /proc/sysemu\n");
426 ent->read_proc = proc_read_sysemu;
427 ent->write_proc = proc_write_sysemu;
432 late_initcall(make_proc_sysemu);
434 int singlestepping(void * t)
436 struct task_struct *task = t ? t : current;
438 if ( ! (task->ptrace & PT_DTRACE) )
441 if (task->thread.singlestep_syscall)
448 * Only x86 and x86_64 have an arch_align_stack().
449 * All other arches have "#define arch_align_stack(x) (x)"
450 * in their asm/system.h
451 * As this is included in UML from asm-um/system-generic.h,
452 * we can use it to behave as the subarch does.
454 #ifndef arch_align_stack
455 unsigned long arch_align_stack(unsigned long sp)
457 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
458 sp -= get_random_int() % 8192;