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/module.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/slab.h>
17 #include <linux/sched.h>
18 #include <linux/seq_file.h>
19 #include <linux/tick.h>
20 #include <linux/threads.h>
21 #include <linux/tracehook.h>
22 #include <asm/current.h>
23 #include <asm/pgtable.h>
24 #include <asm/mmu_context.h>
25 #include <asm/uaccess.h>
26 #include <as-layout.h>
27 #include <kern_util.h>
32 * This is a per-cpu array. A processor only modifies its entry and it only
33 * cares about its entry, so it's OK if another processor is modifying its
36 struct cpu_task cpu_tasks[NR_CPUS] = { [0 ... NR_CPUS - 1] = { -1, NULL } };
38 static inline int external_pid(void)
40 /* FIXME: Need to look up userspace_pid by cpu */
41 return userspace_pid[0];
44 int pid_to_processor_id(int pid)
48 for (i = 0; i < ncpus; i++) {
49 if (cpu_tasks[i].pid == pid)
55 void free_stack(unsigned long stack, int order)
57 free_pages(stack, order);
60 unsigned long alloc_stack(int order, int atomic)
63 gfp_t flags = GFP_KERNEL;
67 page = __get_free_pages(flags, order);
72 static inline void set_current(struct task_struct *task)
74 cpu_tasks[task_thread_info(task)->cpu] = ((struct cpu_task)
75 { external_pid(), task });
78 extern void arch_switch_to(struct task_struct *to);
80 void *__switch_to(struct task_struct *from, struct task_struct *to)
82 to->thread.prev_sched = from;
85 switch_threads(&from->thread.switch_buf, &to->thread.switch_buf);
86 arch_switch_to(current);
88 return current->thread.prev_sched;
91 void interrupt_end(void)
95 if (test_thread_flag(TIF_SIGPENDING))
97 if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME))
98 tracehook_notify_resume(¤t->thread.regs);
101 void exit_thread(void)
105 int get_current_pid(void)
107 return task_pid_nr(current);
111 * This is called magically, by its address being stuffed in a jmp_buf
112 * and being longjmp-d to.
114 void new_thread_handler(void)
116 int (*fn)(void *), n;
119 if (current->thread.prev_sched != NULL)
120 schedule_tail(current->thread.prev_sched);
121 current->thread.prev_sched = NULL;
123 fn = current->thread.request.u.thread.proc;
124 arg = current->thread.request.u.thread.arg;
127 * callback returns only if the kernel thread execs a process
130 userspace(¤t->thread.regs.regs);
133 /* Called magically, see new_thread_handler above */
134 void fork_handler(void)
138 schedule_tail(current->thread.prev_sched);
141 * XXX: if interrupt_end() calls schedule, this call to
142 * arch_switch_to isn't needed. We could want to apply this to
143 * improve performance. -bb
145 arch_switch_to(current);
147 current->thread.prev_sched = NULL;
149 userspace(¤t->thread.regs.regs);
152 int copy_thread(unsigned long clone_flags, unsigned long sp,
153 unsigned long arg, struct task_struct * p)
155 void (*handler)(void);
156 int kthread = current->flags & PF_KTHREAD;
159 p->thread = (struct thread_struct) INIT_THREAD;
162 memcpy(&p->thread.regs.regs, current_pt_regs(),
163 sizeof(p->thread.regs.regs));
164 PT_REGS_SET_SYSCALL_RETURN(&p->thread.regs, 0);
166 REGS_SP(p->thread.regs.regs.gp) = sp;
168 handler = fork_handler;
170 arch_copy_thread(¤t->thread.arch, &p->thread.arch);
172 get_safe_registers(p->thread.regs.regs.gp, p->thread.regs.regs.fp);
173 p->thread.request.u.thread.proc = (int (*)(void *))sp;
174 p->thread.request.u.thread.arg = (void *)arg;
175 handler = new_thread_handler;
178 new_thread(task_stack_page(p), &p->thread.switch_buf, handler);
181 clear_flushed_tls(p);
184 * Set a new TLS for the child thread?
186 if (clone_flags & CLONE_SETTLS)
187 ret = arch_copy_tls(p);
193 void initial_thread_cb(void (*proc)(void *), void *arg)
195 int save_kmalloc_ok = kmalloc_ok;
198 initial_thread_cb_skas(proc, arg);
199 kmalloc_ok = save_kmalloc_ok;
202 void arch_cpu_idle(void)
204 unsigned long long nsecs;
206 cpu_tasks[current_thread_info()->cpu].pid = os_getpid();
207 nsecs = disable_timer();
212 int __cant_sleep(void) {
213 return in_atomic() || irqs_disabled() || in_interrupt();
214 /* Is in_interrupt() really needed? */
217 int user_context(unsigned long sp)
221 stack = sp & (PAGE_MASK << CONFIG_KERNEL_STACK_ORDER);
222 return stack != (unsigned long) current_thread_info();
225 extern exitcall_t __uml_exitcall_begin, __uml_exitcall_end;
227 void do_uml_exitcalls(void)
231 call = &__uml_exitcall_end;
232 while (--call >= &__uml_exitcall_begin)
236 char *uml_strdup(const char *string)
238 return kstrdup(string, GFP_KERNEL);
240 EXPORT_SYMBOL(uml_strdup);
242 int copy_to_user_proc(void __user *to, void *from, int size)
244 return copy_to_user(to, from, size);
247 int copy_from_user_proc(void *to, void __user *from, int size)
249 return copy_from_user(to, from, size);
252 int clear_user_proc(void __user *buf, int size)
254 return clear_user(buf, size);
257 int strlen_user_proc(char __user *str)
259 return strlen_user(str);
264 return current_thread_info()->cpu;
267 static atomic_t using_sysemu = ATOMIC_INIT(0);
268 int sysemu_supported;
270 void set_using_sysemu(int value)
272 if (value > sysemu_supported)
274 atomic_set(&using_sysemu, value);
277 int get_using_sysemu(void)
279 return atomic_read(&using_sysemu);
282 static int sysemu_proc_show(struct seq_file *m, void *v)
284 seq_printf(m, "%d\n", get_using_sysemu());
288 static int sysemu_proc_open(struct inode *inode, struct file *file)
290 return single_open(file, sysemu_proc_show, NULL);
293 static ssize_t sysemu_proc_write(struct file *file, const char __user *buf,
294 size_t count, loff_t *pos)
298 if (copy_from_user(tmp, buf, 1))
301 if (tmp[0] >= '0' && tmp[0] <= '2')
302 set_using_sysemu(tmp[0] - '0');
303 /* We use the first char, but pretend to write everything */
307 static const struct file_operations sysemu_proc_fops = {
308 .owner = THIS_MODULE,
309 .open = sysemu_proc_open,
312 .release = single_release,
313 .write = sysemu_proc_write,
316 int __init make_proc_sysemu(void)
318 struct proc_dir_entry *ent;
319 if (!sysemu_supported)
322 ent = proc_create("sysemu", 0600, NULL, &sysemu_proc_fops);
326 printk(KERN_WARNING "Failed to register /proc/sysemu\n");
333 late_initcall(make_proc_sysemu);
335 int singlestepping(void * t)
337 struct task_struct *task = t ? t : current;
339 if (!(task->ptrace & PT_DTRACE))
342 if (task->thread.singlestep_syscall)
349 * Only x86 and x86_64 have an arch_align_stack().
350 * All other arches have "#define arch_align_stack(x) (x)"
351 * in their asm/exec.h
352 * As this is included in UML from asm-um/system-generic.h,
353 * we can use it to behave as the subarch does.
355 #ifndef arch_align_stack
356 unsigned long arch_align_stack(unsigned long sp)
358 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
359 sp -= get_random_int() % 8192;
364 unsigned long get_wchan(struct task_struct *p)
366 unsigned long stack_page, sp, ip;
369 if ((p == NULL) || (p == current) || (p->state == TASK_RUNNING))
372 stack_page = (unsigned long) task_stack_page(p);
373 /* Bail if the process has no kernel stack for some reason */
377 sp = p->thread.switch_buf->JB_SP;
379 * Bail if the stack pointer is below the bottom of the kernel
380 * stack for some reason
385 while (sp < stack_page + THREAD_SIZE) {
386 ip = *((unsigned long *) sp);
387 if (in_sched_functions(ip))
388 /* Ignore everything until we're above the scheduler */
390 else if (kernel_text_address(ip) && seen_sched)
393 sp += sizeof(unsigned long);
399 int elf_core_copy_fpregs(struct task_struct *t, elf_fpregset_t *fpu)
401 int cpu = current_thread_info()->cpu;
403 return save_fp_registers(userspace_pid[cpu], (unsigned long *) fpu);