[PATCH] mm: uml pte atomicity
[linux-2.6.git] / arch / um / kernel / process_kern.c
1 /* 
2  * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
3  * Copyright 2003 PathScale, Inc.
4  * Licensed under the GPL
5  */
6
7 #include "linux/config.h"
8 #include "linux/kernel.h"
9 #include "linux/sched.h"
10 #include "linux/interrupt.h"
11 #include "linux/string.h"
12 #include "linux/mm.h"
13 #include "linux/slab.h"
14 #include "linux/utsname.h"
15 #include "linux/fs.h"
16 #include "linux/utime.h"
17 #include "linux/smp_lock.h"
18 #include "linux/module.h"
19 #include "linux/init.h"
20 #include "linux/capability.h"
21 #include "linux/vmalloc.h"
22 #include "linux/spinlock.h"
23 #include "linux/proc_fs.h"
24 #include "linux/ptrace.h"
25 #include "linux/random.h"
26 #include "asm/unistd.h"
27 #include "asm/mman.h"
28 #include "asm/segment.h"
29 #include "asm/stat.h"
30 #include "asm/pgtable.h"
31 #include "asm/processor.h"
32 #include "asm/tlbflush.h"
33 #include "asm/uaccess.h"
34 #include "asm/user.h"
35 #include "user_util.h"
36 #include "kern_util.h"
37 #include "kern.h"
38 #include "signal_kern.h"
39 #include "signal_user.h"
40 #include "init.h"
41 #include "irq_user.h"
42 #include "mem_user.h"
43 #include "time_user.h"
44 #include "tlb.h"
45 #include "frame_kern.h"
46 #include "sigcontext.h"
47 #include "os.h"
48 #include "mode.h"
49 #include "mode_kern.h"
50 #include "choose-mode.h"
51
52 /* This is a per-cpu array.  A processor only modifies its entry and it only
53  * cares about its entry, so it's OK if another processor is modifying its
54  * entry.
55  */
56 struct cpu_task cpu_tasks[NR_CPUS] = { [0 ... NR_CPUS - 1] = { -1, NULL } };
57
58 int external_pid(void *t)
59 {
60         struct task_struct *task = t ? t : current;
61
62         return(CHOOSE_MODE_PROC(external_pid_tt, external_pid_skas, task));
63 }
64
65 int pid_to_processor_id(int pid)
66 {
67         int i;
68
69         for(i = 0; i < ncpus; i++){
70                 if(cpu_tasks[i].pid == pid) return(i);
71         }
72         return(-1);
73 }
74
75 void free_stack(unsigned long stack, int order)
76 {
77         free_pages(stack, order);
78 }
79
80 unsigned long alloc_stack(int order, int atomic)
81 {
82         unsigned long page;
83         gfp_t flags = GFP_KERNEL;
84
85         if (atomic)
86                 flags = GFP_ATOMIC;
87         page = __get_free_pages(flags, order);
88         if(page == 0)
89                 return(0);
90         stack_protections(page);
91         return(page);
92 }
93
94 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
95 {
96         int pid;
97
98         current->thread.request.u.thread.proc = fn;
99         current->thread.request.u.thread.arg = arg;
100         pid = do_fork(CLONE_VM | CLONE_UNTRACED | flags, 0,
101                       &current->thread.regs, 0, NULL, NULL);
102         if(pid < 0)
103                 panic("do_fork failed in kernel_thread, errno = %d", pid);
104         return(pid);
105 }
106
107 void set_current(void *t)
108 {
109         struct task_struct *task = t;
110
111         cpu_tasks[task->thread_info->cpu] = ((struct cpu_task) 
112                 { external_pid(task), task });
113 }
114
115 void *_switch_to(void *prev, void *next, void *last)
116 {
117         struct task_struct *from = prev;
118         struct task_struct *to= next;
119
120         to->thread.prev_sched = from;
121         set_current(to);
122
123         do {
124                 current->thread.saved_task = NULL ;
125                 CHOOSE_MODE_PROC(switch_to_tt, switch_to_skas, prev, next);
126                 if(current->thread.saved_task)
127                         show_regs(&(current->thread.regs));
128                 next= current->thread.saved_task;
129                 prev= current;
130         } while(current->thread.saved_task);
131
132         return(current->thread.prev_sched);
133
134 }
135
136 void interrupt_end(void)
137 {
138         if(need_resched()) schedule();
139         if(test_tsk_thread_flag(current, TIF_SIGPENDING)) do_signal();
140 }
141
142 void release_thread(struct task_struct *task)
143 {
144         CHOOSE_MODE(release_thread_tt(task), release_thread_skas(task));
145 }
146  
147 void exit_thread(void)
148 {
149         unprotect_stack((unsigned long) current_thread);
150 }
151  
152 void *get_current(void)
153 {
154         return(current);
155 }
156
157 int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
158                 unsigned long stack_top, struct task_struct * p, 
159                 struct pt_regs *regs)
160 {
161         p->thread = (struct thread_struct) INIT_THREAD;
162         return(CHOOSE_MODE_PROC(copy_thread_tt, copy_thread_skas, nr, 
163                                 clone_flags, sp, stack_top, p, regs));
164 }
165
166 void initial_thread_cb(void (*proc)(void *), void *arg)
167 {
168         int save_kmalloc_ok = kmalloc_ok;
169
170         kmalloc_ok = 0;
171         CHOOSE_MODE_PROC(initial_thread_cb_tt, initial_thread_cb_skas, proc, 
172                          arg);
173         kmalloc_ok = save_kmalloc_ok;
174 }
175  
176 unsigned long stack_sp(unsigned long page)
177 {
178         return(page + PAGE_SIZE - sizeof(void *));
179 }
180
181 int current_pid(void)
182 {
183         return(current->pid);
184 }
185
186 void default_idle(void)
187 {
188         CHOOSE_MODE(uml_idle_timer(), (void) 0);
189
190         atomic_inc(&init_mm.mm_count);
191         current->mm = &init_mm;
192         current->active_mm = &init_mm;
193
194         while(1){
195                 /* endless idle loop with no priority at all */
196
197                 /*
198                  * although we are an idle CPU, we do not want to
199                  * get into the scheduler unnecessarily.
200                  */
201                 if(need_resched())
202                         schedule();
203                 
204                 idle_sleep(10);
205         }
206 }
207
208 void cpu_idle(void)
209 {
210         CHOOSE_MODE(init_idle_tt(), init_idle_skas());
211 }
212
213 int page_size(void)
214 {
215         return(PAGE_SIZE);
216 }
217
218 void *um_virt_to_phys(struct task_struct *task, unsigned long addr, 
219                       pte_t *pte_out)
220 {
221         pgd_t *pgd;
222         pud_t *pud;
223         pmd_t *pmd;
224         pte_t *pte;
225         pte_t ptent;
226
227         if(task->mm == NULL) 
228                 return(ERR_PTR(-EINVAL));
229         pgd = pgd_offset(task->mm, addr);
230         if(!pgd_present(*pgd))
231                 return(ERR_PTR(-EINVAL));
232
233         pud = pud_offset(pgd, addr);
234         if(!pud_present(*pud))
235                 return(ERR_PTR(-EINVAL));
236
237         pmd = pmd_offset(pud, addr);
238         if(!pmd_present(*pmd)) 
239                 return(ERR_PTR(-EINVAL));
240
241         pte = pte_offset_kernel(pmd, addr);
242         ptent = *pte;
243         if(!pte_present(ptent))
244                 return(ERR_PTR(-EINVAL));
245
246         if(pte_out != NULL)
247                 *pte_out = ptent;
248         return((void *) (pte_val(ptent) & PAGE_MASK) + (addr & ~PAGE_MASK));
249 }
250
251 char *current_cmd(void)
252 {
253 #if defined(CONFIG_SMP) || defined(CONFIG_HIGHMEM)
254         return("(Unknown)");
255 #else
256         void *addr = um_virt_to_phys(current, current->mm->arg_start, NULL);
257         return IS_ERR(addr) ? "(Unknown)": __va((unsigned long) addr);
258 #endif
259 }
260
261 void force_sigbus(void)
262 {
263         printk(KERN_ERR "Killing pid %d because of a lack of memory\n", 
264                current->pid);
265         lock_kernel();
266         sigaddset(&current->pending.signal, SIGBUS);
267         recalc_sigpending();
268         current->flags |= PF_SIGNALED;
269         do_exit(SIGBUS | 0x80);
270 }
271
272 void dump_thread(struct pt_regs *regs, struct user *u)
273 {
274 }
275
276 void enable_hlt(void)
277 {
278         panic("enable_hlt");
279 }
280
281 EXPORT_SYMBOL(enable_hlt);
282
283 void disable_hlt(void)
284 {
285         panic("disable_hlt");
286 }
287
288 EXPORT_SYMBOL(disable_hlt);
289
290 void *um_kmalloc(int size)
291 {
292         return(kmalloc(size, GFP_KERNEL));
293 }
294
295 void *um_kmalloc_atomic(int size)
296 {
297         return(kmalloc(size, GFP_ATOMIC));
298 }
299
300 void *um_vmalloc(int size)
301 {
302         return(vmalloc(size));
303 }
304
305 unsigned long get_fault_addr(void)
306 {
307         return((unsigned long) current->thread.fault_addr);
308 }
309
310 EXPORT_SYMBOL(get_fault_addr);
311
312 void not_implemented(void)
313 {
314         printk(KERN_DEBUG "Something isn't implemented in here\n");
315 }
316
317 EXPORT_SYMBOL(not_implemented);
318
319 int user_context(unsigned long sp)
320 {
321         unsigned long stack;
322
323         stack = sp & (PAGE_MASK << CONFIG_KERNEL_STACK_ORDER);
324         return(stack != (unsigned long) current_thread);
325 }
326
327 extern void remove_umid_dir(void);
328
329 __uml_exitcall(remove_umid_dir);
330
331 extern exitcall_t __uml_exitcall_begin, __uml_exitcall_end;
332
333 void do_uml_exitcalls(void)
334 {
335         exitcall_t *call;
336
337         call = &__uml_exitcall_end;
338         while (--call >= &__uml_exitcall_begin)
339                 (*call)();
340 }
341
342 char *uml_strdup(char *string)
343 {
344         return kstrdup(string, GFP_KERNEL);
345 }
346
347 int copy_to_user_proc(void __user *to, void *from, int size)
348 {
349         return(copy_to_user(to, from, size));
350 }
351
352 int copy_from_user_proc(void *to, void __user *from, int size)
353 {
354         return(copy_from_user(to, from, size));
355 }
356
357 int clear_user_proc(void __user *buf, int size)
358 {
359         return(clear_user(buf, size));
360 }
361
362 int strlen_user_proc(char __user *str)
363 {
364         return(strlen_user(str));
365 }
366
367 int smp_sigio_handler(void)
368 {
369 #ifdef CONFIG_SMP
370         int cpu = current_thread->cpu;
371         IPI_handler(cpu);
372         if(cpu != 0)
373                 return(1);
374 #endif
375         return(0);
376 }
377
378 int um_in_interrupt(void)
379 {
380         return(in_interrupt());
381 }
382
383 int cpu(void)
384 {
385         return(current_thread->cpu);
386 }
387
388 static atomic_t using_sysemu = ATOMIC_INIT(0);
389 int sysemu_supported;
390
391 void set_using_sysemu(int value)
392 {
393         if (value > sysemu_supported)
394                 return;
395         atomic_set(&using_sysemu, value);
396 }
397
398 int get_using_sysemu(void)
399 {
400         return atomic_read(&using_sysemu);
401 }
402
403 static int proc_read_sysemu(char *buf, char **start, off_t offset, int size,int *eof, void *data)
404 {
405         if (snprintf(buf, size, "%d\n", get_using_sysemu()) < size) /*No overflow*/
406                 *eof = 1;
407
408         return strlen(buf);
409 }
410
411 static int proc_write_sysemu(struct file *file,const char *buf, unsigned long count,void *data)
412 {
413         char tmp[2];
414
415         if (copy_from_user(tmp, buf, 1))
416                 return -EFAULT;
417
418         if (tmp[0] >= '0' && tmp[0] <= '2')
419                 set_using_sysemu(tmp[0] - '0');
420         return count; /*We use the first char, but pretend to write everything*/
421 }
422
423 int __init make_proc_sysemu(void)
424 {
425         struct proc_dir_entry *ent;
426         if (!sysemu_supported)
427                 return 0;
428
429         ent = create_proc_entry("sysemu", 0600, &proc_root);
430
431         if (ent == NULL)
432         {
433                 printk(KERN_WARNING "Failed to register /proc/sysemu\n");
434                 return(0);
435         }
436
437         ent->read_proc  = proc_read_sysemu;
438         ent->write_proc = proc_write_sysemu;
439
440         return 0;
441 }
442
443 late_initcall(make_proc_sysemu);
444
445 int singlestepping(void * t)
446 {
447         struct task_struct *task = t ? t : current;
448
449         if ( ! (task->ptrace & PT_DTRACE) )
450                 return(0);
451
452         if (task->thread.singlestep_syscall)
453                 return(1);
454
455         return 2;
456 }
457
458 /*
459  * Only x86 and x86_64 have an arch_align_stack().
460  * All other arches have "#define arch_align_stack(x) (x)"
461  * in their asm/system.h
462  * As this is included in UML from asm-um/system-generic.h,
463  * we can use it to behave as the subarch does.
464  */
465 #ifndef arch_align_stack
466 unsigned long arch_align_stack(unsigned long sp)
467 {
468         if (randomize_va_space)
469                 sp -= get_random_int() % 8192;
470         return sp & ~0xf;
471 }
472 #endif