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
);
67 int kernel_thread(int (*fn
)(void *), void * arg
, unsigned long flags
)
71 current
->thread
.request
.u
.thread
.proc
= fn
;
72 current
->thread
.request
.u
.thread
.arg
= arg
;
73 pid
= do_fork(CLONE_VM
| CLONE_UNTRACED
| flags
, 0,
74 ¤t
->thread
.regs
, 0, NULL
, NULL
);
78 static inline void set_current(struct task_struct
*task
)
80 cpu_tasks
[task_thread_info(task
)->cpu
] = ((struct cpu_task
)
81 { external_pid(task
), task
});
84 extern void arch_switch_to(struct task_struct
*from
, struct task_struct
*to
);
86 void *_switch_to(void *prev
, void *next
, void *last
)
88 struct task_struct
*from
= prev
;
89 struct task_struct
*to
= next
;
91 to
->thread
.prev_sched
= from
;
95 current
->thread
.saved_task
= NULL
;
97 switch_threads(&from
->thread
.switch_buf
,
98 &to
->thread
.switch_buf
);
100 arch_switch_to(current
->thread
.prev_sched
, current
);
102 if (current
->thread
.saved_task
)
103 show_regs(&(current
->thread
.regs
));
104 next
= current
->thread
.saved_task
;
106 } while(current
->thread
.saved_task
);
108 return current
->thread
.prev_sched
;
112 void interrupt_end(void)
116 if (test_tsk_thread_flag(current
, TIF_SIGPENDING
))
120 void exit_thread(void)
124 void *get_current(void)
129 extern void schedule_tail(struct task_struct
*prev
);
132 * This is called magically, by its address being stuffed in a jmp_buf
133 * and being longjmp-d to.
135 void new_thread_handler(void)
137 int (*fn
)(void *), n
;
140 if (current
->thread
.prev_sched
!= NULL
)
141 schedule_tail(current
->thread
.prev_sched
);
142 current
->thread
.prev_sched
= NULL
;
144 fn
= current
->thread
.request
.u
.thread
.proc
;
145 arg
= current
->thread
.request
.u
.thread
.arg
;
148 * The return value is 1 if the kernel thread execs a process,
151 n
= run_kernel_thread(fn
, arg
, ¤t
->thread
.exec_buf
);
153 /* Handle any immediate reschedules or signals */
155 userspace(¤t
->thread
.regs
.regs
);
160 /* Called magically, see new_thread_handler above */
161 void fork_handler(void)
164 if (current
->thread
.prev_sched
== NULL
)
167 schedule_tail(current
->thread
.prev_sched
);
170 * XXX: if interrupt_end() calls schedule, this call to
171 * arch_switch_to isn't needed. We could want to apply this to
172 * improve performance. -bb
174 arch_switch_to(current
->thread
.prev_sched
, current
);
176 current
->thread
.prev_sched
= NULL
;
178 /* Handle any immediate reschedules or signals */
181 userspace(¤t
->thread
.regs
.regs
);
184 int copy_thread(int nr
, unsigned long clone_flags
, unsigned long sp
,
185 unsigned long stack_top
, struct task_struct
* p
,
186 struct pt_regs
*regs
)
188 void (*handler
)(void);
191 p
->thread
= (struct thread_struct
) INIT_THREAD
;
193 if (current
->thread
.forking
) {
194 memcpy(&p
->thread
.regs
.regs
, ®s
->regs
,
195 sizeof(p
->thread
.regs
.regs
));
196 REGS_SET_SYSCALL_RETURN(p
->thread
.regs
.regs
.gp
, 0);
198 REGS_SP(p
->thread
.regs
.regs
.gp
) = sp
;
200 handler
= fork_handler
;
202 arch_copy_thread(¤t
->thread
.arch
, &p
->thread
.arch
);
205 init_thread_registers(&p
->thread
.regs
.regs
);
206 p
->thread
.request
.u
.thread
= current
->thread
.request
.u
.thread
;
207 handler
= new_thread_handler
;
210 new_thread(task_stack_page(p
), &p
->thread
.switch_buf
, handler
);
212 if (current
->thread
.forking
) {
213 clear_flushed_tls(p
);
216 * Set a new TLS for the child thread?
218 if (clone_flags
& CLONE_SETTLS
)
219 ret
= arch_copy_tls(p
);
225 void initial_thread_cb(void (*proc
)(void *), void *arg
)
227 int save_kmalloc_ok
= kmalloc_ok
;
230 initial_thread_cb_skas(proc
, arg
);
231 kmalloc_ok
= save_kmalloc_ok
;
234 void default_idle(void)
236 unsigned long long nsecs
;
239 /* endless idle loop with no priority at all */
242 * although we are an idle CPU, we do not want to
243 * get into the scheduler unnecessarily.
248 tick_nohz_stop_sched_tick();
249 nsecs
= disable_timer();
251 tick_nohz_restart_sched_tick();
257 cpu_tasks
[current_thread
->cpu
].pid
= os_getpid();
261 void *um_virt_to_phys(struct task_struct
*task
, unsigned long addr
,
270 if (task
->mm
== NULL
)
271 return ERR_PTR(-EINVAL
);
272 pgd
= pgd_offset(task
->mm
, addr
);
273 if (!pgd_present(*pgd
))
274 return ERR_PTR(-EINVAL
);
276 pud
= pud_offset(pgd
, addr
);
277 if (!pud_present(*pud
))
278 return ERR_PTR(-EINVAL
);
280 pmd
= pmd_offset(pud
, addr
);
281 if (!pmd_present(*pmd
))
282 return ERR_PTR(-EINVAL
);
284 pte
= pte_offset_kernel(pmd
, addr
);
286 if (!pte_present(ptent
))
287 return ERR_PTR(-EINVAL
);
291 return (void *) (pte_val(ptent
) & PAGE_MASK
) + (addr
& ~PAGE_MASK
);
294 char *current_cmd(void)
296 #if defined(CONFIG_SMP) || defined(CONFIG_HIGHMEM)
299 void *addr
= um_virt_to_phys(current
, current
->mm
->arg_start
, NULL
);
300 return IS_ERR(addr
) ? "(Unknown)": __va((unsigned long) addr
);
304 void dump_thread(struct pt_regs
*regs
, struct user
*u
)
308 int __cant_sleep(void) {
309 return in_atomic() || irqs_disabled() || in_interrupt();
310 /* Is in_interrupt() really needed? */
313 int user_context(unsigned long sp
)
317 stack
= sp
& (PAGE_MASK
<< CONFIG_KERNEL_STACK_ORDER
);
318 return stack
!= (unsigned long) current_thread
;
321 extern exitcall_t __uml_exitcall_begin
, __uml_exitcall_end
;
323 void do_uml_exitcalls(void)
327 call
= &__uml_exitcall_end
;
328 while (--call
>= &__uml_exitcall_begin
)
332 char *uml_strdup(const char *string
)
334 return kstrdup(string
, GFP_KERNEL
);
337 int copy_to_user_proc(void __user
*to
, void *from
, int size
)
339 return copy_to_user(to
, from
, size
);
342 int copy_from_user_proc(void *to
, void __user
*from
, int size
)
344 return copy_from_user(to
, from
, size
);
347 int clear_user_proc(void __user
*buf
, int size
)
349 return clear_user(buf
, size
);
352 int strlen_user_proc(char __user
*str
)
354 return strlen_user(str
);
357 int smp_sigio_handler(void)
360 int cpu
= current_thread
->cpu
;
370 return current_thread
->cpu
;
373 static atomic_t using_sysemu
= ATOMIC_INIT(0);
374 int sysemu_supported
;
376 void set_using_sysemu(int value
)
378 if (value
> sysemu_supported
)
380 atomic_set(&using_sysemu
, value
);
383 int get_using_sysemu(void)
385 return atomic_read(&using_sysemu
);
388 static int proc_read_sysemu(char *buf
, char **start
, off_t offset
, int size
,int *eof
, void *data
)
390 if (snprintf(buf
, size
, "%d\n", get_using_sysemu()) < size
)
397 static int proc_write_sysemu(struct file
*file
,const char __user
*buf
, unsigned long count
,void *data
)
401 if (copy_from_user(tmp
, buf
, 1))
404 if (tmp
[0] >= '0' && tmp
[0] <= '2')
405 set_using_sysemu(tmp
[0] - '0');
406 /* We use the first char, but pretend to write everything */
410 int __init
make_proc_sysemu(void)
412 struct proc_dir_entry
*ent
;
413 if (!sysemu_supported
)
416 ent
= create_proc_entry("sysemu", 0600, &proc_root
);
420 printk(KERN_WARNING
"Failed to register /proc/sysemu\n");
424 ent
->read_proc
= proc_read_sysemu
;
425 ent
->write_proc
= proc_write_sysemu
;
430 late_initcall(make_proc_sysemu
);
432 int singlestepping(void * t
)
434 struct task_struct
*task
= t
? t
: current
;
436 if ( ! (task
->ptrace
& PT_DTRACE
) )
439 if (task
->thread
.singlestep_syscall
)
446 * Only x86 and x86_64 have an arch_align_stack().
447 * All other arches have "#define arch_align_stack(x) (x)"
448 * in their asm/system.h
449 * As this is included in UML from asm-um/system-generic.h,
450 * we can use it to behave as the subarch does.
452 #ifndef arch_align_stack
453 unsigned long arch_align_stack(unsigned long sp
)
455 if (!(current
->personality
& ADDR_NO_RANDOMIZE
) && randomize_va_space
)
456 sp
-= get_random_int() % 8192;
461 unsigned long get_wchan(struct task_struct
*p
)
463 unsigned long stack_page
, sp
, ip
;
466 if ((p
== NULL
) || (p
== current
) || (p
->state
== TASK_RUNNING
))
469 stack_page
= (unsigned long) task_stack_page(p
);
470 /* Bail if the process has no kernel stack for some reason */
474 sp
= p
->thread
.switch_buf
->JB_SP
;
476 * Bail if the stack pointer is below the bottom of the kernel
477 * stack for some reason
482 while (sp
< stack_page
+ THREAD_SIZE
) {
483 ip
= *((unsigned long *) sp
);
484 if (in_sched_functions(ip
))
485 /* Ignore everything until we're above the scheduler */
487 else if (kernel_text_address(ip
) && seen_sched
)
490 sp
+= sizeof(unsigned long);