a57723808743e65c82b89e7746adda447b536ce3
[linux-2.6.git] / arch / blackfin / kernel / process.c
1 /*
2  * Blackfin architecture-dependent process handling
3  *
4  * Copyright 2004-2009 Analog Devices Inc.
5  *
6  * Licensed under the GPL-2 or later
7  */
8
9 #include <linux/module.h>
10 #include <linux/smp_lock.h>
11 #include <linux/unistd.h>
12 #include <linux/user.h>
13 #include <linux/uaccess.h>
14 #include <linux/sched.h>
15 #include <linux/tick.h>
16 #include <linux/fs.h>
17 #include <linux/err.h>
18
19 #include <asm/blackfin.h>
20 #include <asm/fixed_code.h>
21 #include <asm/mem_map.h>
22
23 asmlinkage void ret_from_fork(void);
24
25 /* Points to the SDRAM backup memory for the stack that is currently in
26  * L1 scratchpad memory.
27  */
28 void *current_l1_stack_save;
29
30 /* The number of tasks currently using a L1 stack area.  The SRAM is
31  * allocated/deallocated whenever this changes from/to zero.
32  */
33 int nr_l1stack_tasks;
34
35 /* Start and length of the area in L1 scratchpad memory which we've allocated
36  * for process stacks.
37  */
38 void *l1_stack_base;
39 unsigned long l1_stack_len;
40
41 /*
42  * Powermanagement idle function, if any..
43  */
44 void (*pm_idle)(void) = NULL;
45 EXPORT_SYMBOL(pm_idle);
46
47 void (*pm_power_off)(void) = NULL;
48 EXPORT_SYMBOL(pm_power_off);
49
50 /*
51  * The idle loop on BFIN
52  */
53 #ifdef CONFIG_IDLE_L1
54 static void default_idle(void)__attribute__((l1_text));
55 void cpu_idle(void)__attribute__((l1_text));
56 #endif
57
58 /*
59  * This is our default idle handler.  We need to disable
60  * interrupts here to ensure we don't miss a wakeup call.
61  */
62 static void default_idle(void)
63 {
64 #ifdef CONFIG_IPIPE
65         ipipe_suspend_domain();
66 #endif
67         local_irq_disable_hw();
68         if (!need_resched())
69                 idle_with_irq_disabled();
70
71         local_irq_enable_hw();
72 }
73
74 /*
75  * The idle thread.  We try to conserve power, while trying to keep
76  * overall latency low.  The architecture specific idle is passed
77  * a value to indicate the level of "idleness" of the system.
78  */
79 void cpu_idle(void)
80 {
81         /* endless idle loop with no priority at all */
82         while (1) {
83                 void (*idle)(void) = pm_idle;
84
85 #ifdef CONFIG_HOTPLUG_CPU
86                 if (cpu_is_offline(smp_processor_id()))
87                         cpu_die();
88 #endif
89                 if (!idle)
90                         idle = default_idle;
91                 tick_nohz_stop_sched_tick(1);
92                 while (!need_resched())
93                         idle();
94                 tick_nohz_restart_sched_tick();
95                 preempt_enable_no_resched();
96                 schedule();
97                 preempt_disable();
98         }
99 }
100
101 /* Fill in the fpu structure for a core dump.  */
102
103 int dump_fpu(struct pt_regs *regs, elf_fpregset_t * fpregs)
104 {
105         return 1;
106 }
107
108 /*
109  * This gets run with P1 containing the
110  * function to call, and R1 containing
111  * the "args".  Note P0 is clobbered on the way here.
112  */
113 void kernel_thread_helper(void);
114 __asm__(".section .text\n"
115         ".align 4\n"
116         "_kernel_thread_helper:\n\t"
117         "\tsp += -12;\n\t"
118         "\tr0 = r1;\n\t" "\tcall (p1);\n\t" "\tcall _do_exit;\n" ".previous");
119
120 /*
121  * Create a kernel thread.
122  */
123 pid_t kernel_thread(int (*fn) (void *), void *arg, unsigned long flags)
124 {
125         struct pt_regs regs;
126
127         memset(&regs, 0, sizeof(regs));
128
129         regs.r1 = (unsigned long)arg;
130         regs.p1 = (unsigned long)fn;
131         regs.pc = (unsigned long)kernel_thread_helper;
132         regs.orig_p0 = -1;
133         /* Set bit 2 to tell ret_from_fork we should be returning to kernel
134            mode.  */
135         regs.ipend = 0x8002;
136         __asm__ __volatile__("%0 = syscfg;":"=da"(regs.syscfg):);
137         return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL,
138                        NULL);
139 }
140 EXPORT_SYMBOL(kernel_thread);
141
142 /*
143  * Do necessary setup to start up a newly executed thread.
144  *
145  * pass the data segment into user programs if it exists,
146  * it can't hurt anything as far as I can tell
147  */
148 void start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
149 {
150         set_fs(USER_DS);
151         regs->pc = new_ip;
152         if (current->mm)
153                 regs->p5 = current->mm->start_data;
154 #ifndef CONFIG_SMP
155         task_thread_info(current)->l1_task_info.stack_start =
156                 (void *)current->mm->context.stack_start;
157         task_thread_info(current)->l1_task_info.lowest_sp = (void *)new_sp;
158         memcpy(L1_SCRATCH_TASK_INFO, &task_thread_info(current)->l1_task_info,
159                sizeof(*L1_SCRATCH_TASK_INFO));
160 #endif
161         wrusp(new_sp);
162 }
163 EXPORT_SYMBOL_GPL(start_thread);
164
165 void flush_thread(void)
166 {
167 }
168
169 asmlinkage int bfin_vfork(struct pt_regs *regs)
170 {
171         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL,
172                        NULL);
173 }
174
175 asmlinkage int bfin_clone(struct pt_regs *regs)
176 {
177         unsigned long clone_flags;
178         unsigned long newsp;
179
180 #ifdef __ARCH_SYNC_CORE_DCACHE
181         if (current->rt.nr_cpus_allowed == num_possible_cpus()) {
182                 current->cpus_allowed = cpumask_of_cpu(smp_processor_id());
183                 current->rt.nr_cpus_allowed = 1;
184         }
185 #endif
186
187         /* syscall2 puts clone_flags in r0 and usp in r1 */
188         clone_flags = regs->r0;
189         newsp = regs->r1;
190         if (!newsp)
191                 newsp = rdusp();
192         else
193                 newsp -= 12;
194         return do_fork(clone_flags, newsp, regs, 0, NULL, NULL);
195 }
196
197 int
198 copy_thread(unsigned long clone_flags,
199             unsigned long usp, unsigned long topstk,
200             struct task_struct *p, struct pt_regs *regs)
201 {
202         struct pt_regs *childregs;
203
204         childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
205         *childregs = *regs;
206         childregs->r0 = 0;
207
208         p->thread.usp = usp;
209         p->thread.ksp = (unsigned long)childregs;
210         p->thread.pc = (unsigned long)ret_from_fork;
211
212         return 0;
213 }
214
215 /*
216  * sys_execve() executes a new program.
217  */
218 asmlinkage int sys_execve(char __user *name, char __user * __user *argv, char __user * __user *envp)
219 {
220         int error;
221         char *filename;
222         struct pt_regs *regs = (struct pt_regs *)((&name) + 6);
223
224         filename = getname(name);
225         error = PTR_ERR(filename);
226         if (IS_ERR(filename))
227                 return error;
228         error = do_execve(filename, argv, envp, regs);
229         putname(filename);
230         return error;
231 }
232
233 unsigned long get_wchan(struct task_struct *p)
234 {
235         unsigned long fp, pc;
236         unsigned long stack_page;
237         int count = 0;
238         if (!p || p == current || p->state == TASK_RUNNING)
239                 return 0;
240
241         stack_page = (unsigned long)p;
242         fp = p->thread.usp;
243         do {
244                 if (fp < stack_page + sizeof(struct thread_info) ||
245                     fp >= 8184 + stack_page)
246                         return 0;
247                 pc = ((unsigned long *)fp)[1];
248                 if (!in_sched_functions(pc))
249                         return pc;
250                 fp = *(unsigned long *)fp;
251         }
252         while (count++ < 16);
253         return 0;
254 }
255
256 void finish_atomic_sections (struct pt_regs *regs)
257 {
258         int __user *up0 = (int __user *)regs->p0;
259
260         switch (regs->pc) {
261         case ATOMIC_XCHG32 + 2:
262                 put_user(regs->r1, up0);
263                 regs->pc = ATOMIC_XCHG32 + 4;
264                 break;
265
266         case ATOMIC_CAS32 + 2:
267         case ATOMIC_CAS32 + 4:
268                 if (regs->r0 == regs->r1)
269         case ATOMIC_CAS32 + 6:
270                         put_user(regs->r2, up0);
271                 regs->pc = ATOMIC_CAS32 + 8;
272                 break;
273
274         case ATOMIC_ADD32 + 2:
275                 regs->r0 = regs->r1 + regs->r0;
276                 /* fall through */
277         case ATOMIC_ADD32 + 4:
278                 put_user(regs->r0, up0);
279                 regs->pc = ATOMIC_ADD32 + 6;
280                 break;
281
282         case ATOMIC_SUB32 + 2:
283                 regs->r0 = regs->r1 - regs->r0;
284                 /* fall through */
285         case ATOMIC_SUB32 + 4:
286                 put_user(regs->r0, up0);
287                 regs->pc = ATOMIC_SUB32 + 6;
288                 break;
289
290         case ATOMIC_IOR32 + 2:
291                 regs->r0 = regs->r1 | regs->r0;
292                 /* fall through */
293         case ATOMIC_IOR32 + 4:
294                 put_user(regs->r0, up0);
295                 regs->pc = ATOMIC_IOR32 + 6;
296                 break;
297
298         case ATOMIC_AND32 + 2:
299                 regs->r0 = regs->r1 & regs->r0;
300                 /* fall through */
301         case ATOMIC_AND32 + 4:
302                 put_user(regs->r0, up0);
303                 regs->pc = ATOMIC_AND32 + 6;
304                 break;
305
306         case ATOMIC_XOR32 + 2:
307                 regs->r0 = regs->r1 ^ regs->r0;
308                 /* fall through */
309         case ATOMIC_XOR32 + 4:
310                 put_user(regs->r0, up0);
311                 regs->pc = ATOMIC_XOR32 + 6;
312                 break;
313         }
314 }
315
316 static inline
317 int in_mem(unsigned long addr, unsigned long size,
318            unsigned long start, unsigned long end)
319 {
320         return addr >= start && addr + size <= end;
321 }
322 static inline
323 int in_mem_const_off(unsigned long addr, unsigned long size, unsigned long off,
324                      unsigned long const_addr, unsigned long const_size)
325 {
326         return const_size &&
327                in_mem(addr, size, const_addr + off, const_addr + const_size);
328 }
329 static inline
330 int in_mem_const(unsigned long addr, unsigned long size,
331                  unsigned long const_addr, unsigned long const_size)
332 {
333         return in_mem_const_off(addr, size, 0, const_addr, const_size);
334 }
335 #define ASYNC_ENABLED(bnum, bctlnum) \
336 ({ \
337         (bfin_read_EBIU_AMGCTL() & 0xe) < ((bnum + 1) << 1) ? 0 : \
338         bfin_read_EBIU_AMBCTL##bctlnum() & B##bnum##RDYEN ? 0 : \
339         1; \
340 })
341 /*
342  * We can't read EBIU banks that aren't enabled or we end up hanging
343  * on the access to the async space.  Make sure we validate accesses
344  * that cross async banks too.
345  *      0 - found, but unusable
346  *      1 - found & usable
347  *      2 - not found
348  */
349 static
350 int in_async(unsigned long addr, unsigned long size)
351 {
352         if (addr >= ASYNC_BANK0_BASE && addr < ASYNC_BANK0_BASE + ASYNC_BANK0_SIZE) {
353                 if (!ASYNC_ENABLED(0, 0))
354                         return 0;
355                 if (addr + size <= ASYNC_BANK0_BASE + ASYNC_BANK0_SIZE)
356                         return 1;
357                 size -= ASYNC_BANK0_BASE + ASYNC_BANK0_SIZE - addr;
358                 addr = ASYNC_BANK0_BASE + ASYNC_BANK0_SIZE;
359         }
360         if (addr >= ASYNC_BANK1_BASE && addr < ASYNC_BANK1_BASE + ASYNC_BANK1_SIZE) {
361                 if (!ASYNC_ENABLED(1, 0))
362                         return 0;
363                 if (addr + size <= ASYNC_BANK1_BASE + ASYNC_BANK1_SIZE)
364                         return 1;
365                 size -= ASYNC_BANK1_BASE + ASYNC_BANK1_SIZE - addr;
366                 addr = ASYNC_BANK1_BASE + ASYNC_BANK1_SIZE;
367         }
368         if (addr >= ASYNC_BANK2_BASE && addr < ASYNC_BANK2_BASE + ASYNC_BANK2_SIZE) {
369                 if (!ASYNC_ENABLED(2, 1))
370                         return 0;
371                 if (addr + size <= ASYNC_BANK2_BASE + ASYNC_BANK2_SIZE)
372                         return 1;
373                 size -= ASYNC_BANK2_BASE + ASYNC_BANK2_SIZE - addr;
374                 addr = ASYNC_BANK2_BASE + ASYNC_BANK2_SIZE;
375         }
376         if (addr >= ASYNC_BANK3_BASE && addr < ASYNC_BANK3_BASE + ASYNC_BANK3_SIZE) {
377                 if (ASYNC_ENABLED(3, 1))
378                         return 0;
379                 if (addr + size <= ASYNC_BANK3_BASE + ASYNC_BANK3_SIZE)
380                         return 1;
381                 return 0;
382         }
383
384         /* not within async bounds */
385         return 2;
386 }
387
388 int bfin_mem_access_type(unsigned long addr, unsigned long size)
389 {
390         int cpu = raw_smp_processor_id();
391
392         /* Check that things do not wrap around */
393         if (addr > ULONG_MAX - size)
394                 return -EFAULT;
395
396         if (in_mem(addr, size, FIXED_CODE_START, physical_mem_end))
397                 return BFIN_MEM_ACCESS_CORE;
398
399         if (in_mem_const(addr, size, L1_CODE_START, L1_CODE_LENGTH))
400                 return cpu == 0 ? BFIN_MEM_ACCESS_ITEST : BFIN_MEM_ACCESS_IDMA;
401         if (in_mem_const(addr, size, L1_SCRATCH_START, L1_SCRATCH_LENGTH))
402                 return cpu == 0 ? BFIN_MEM_ACCESS_CORE_ONLY : -EFAULT;
403         if (in_mem_const(addr, size, L1_DATA_A_START, L1_DATA_A_LENGTH))
404                 return cpu == 0 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
405         if (in_mem_const(addr, size, L1_DATA_B_START, L1_DATA_B_LENGTH))
406                 return cpu == 0 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
407 #ifdef COREB_L1_CODE_START
408         if (in_mem_const(addr, size, COREB_L1_CODE_START, COREB_L1_CODE_LENGTH))
409                 return cpu == 1 ? BFIN_MEM_ACCESS_ITEST : BFIN_MEM_ACCESS_IDMA;
410         if (in_mem_const(addr, size, COREB_L1_SCRATCH_START, L1_SCRATCH_LENGTH))
411                 return cpu == 1 ? BFIN_MEM_ACCESS_CORE_ONLY : -EFAULT;
412         if (in_mem_const(addr, size, COREB_L1_DATA_A_START, COREB_L1_DATA_A_LENGTH))
413                 return cpu == 1 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
414         if (in_mem_const(addr, size, COREB_L1_DATA_B_START, COREB_L1_DATA_B_LENGTH))
415                 return cpu == 1 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
416 #endif
417         if (in_mem_const(addr, size, L2_START, L2_LENGTH))
418                 return BFIN_MEM_ACCESS_CORE;
419
420         if (addr >= SYSMMR_BASE)
421                 return BFIN_MEM_ACCESS_CORE_ONLY;
422
423         switch (in_async(addr, size)) {
424         case 0: return -EFAULT;
425         case 1: return BFIN_MEM_ACCESS_CORE;
426         case 2: /* fall through */;
427         }
428
429         if (in_mem_const(addr, size, BOOT_ROM_START, BOOT_ROM_LENGTH))
430                 return BFIN_MEM_ACCESS_CORE;
431         if (in_mem_const(addr, size, L1_ROM_START, L1_ROM_LENGTH))
432                 return BFIN_MEM_ACCESS_DMA;
433
434         return -EFAULT;
435 }
436
437 #if defined(CONFIG_ACCESS_CHECK)
438 #ifdef CONFIG_ACCESS_OK_L1
439 __attribute__((l1_text))
440 #endif
441 /* Return 1 if access to memory range is OK, 0 otherwise */
442 int _access_ok(unsigned long addr, unsigned long size)
443 {
444         int aret;
445
446         if (size == 0)
447                 return 1;
448         /* Check that things do not wrap around */
449         if (addr > ULONG_MAX - size)
450                 return 0;
451         if (segment_eq(get_fs(), KERNEL_DS))
452                 return 1;
453 #ifdef CONFIG_MTD_UCLINUX
454         if (1)
455 #else
456         if (0)
457 #endif
458         {
459                 if (in_mem(addr, size, memory_start, memory_end))
460                         return 1;
461                 if (in_mem(addr, size, memory_mtd_end, physical_mem_end))
462                         return 1;
463 # ifndef CONFIG_ROMFS_ON_MTD
464                 if (0)
465 # endif
466                         /* For XIP, allow user space to use pointers within the ROMFS.  */
467                         if (in_mem(addr, size, memory_mtd_start, memory_mtd_end))
468                                 return 1;
469         } else {
470                 if (in_mem(addr, size, memory_start, physical_mem_end))
471                         return 1;
472         }
473
474         if (in_mem(addr, size, (unsigned long)__init_begin, (unsigned long)__init_end))
475                 return 1;
476
477         if (in_mem_const(addr, size, L1_CODE_START, L1_CODE_LENGTH))
478                 return 1;
479         if (in_mem_const_off(addr, size, _etext_l1 - _stext_l1, L1_CODE_START, L1_CODE_LENGTH))
480                 return 1;
481         if (in_mem_const_off(addr, size, _ebss_l1 - _sdata_l1, L1_DATA_A_START, L1_DATA_A_LENGTH))
482                 return 1;
483         if (in_mem_const_off(addr, size, _ebss_b_l1 - _sdata_b_l1, L1_DATA_B_START, L1_DATA_B_LENGTH))
484                 return 1;
485 #ifdef COREB_L1_CODE_START
486         if (in_mem_const(addr, size, COREB_L1_CODE_START, COREB_L1_CODE_LENGTH))
487                 return 1;
488         if (in_mem_const(addr, size, COREB_L1_SCRATCH_START, L1_SCRATCH_LENGTH))
489                 return 1;
490         if (in_mem_const(addr, size, COREB_L1_DATA_A_START, COREB_L1_DATA_A_LENGTH))
491                 return 1;
492         if (in_mem_const(addr, size, COREB_L1_DATA_B_START, COREB_L1_DATA_B_LENGTH))
493                 return 1;
494 #endif
495
496         aret = in_async(addr, size);
497         if (aret < 2)
498                 return aret;
499
500         if (in_mem_const_off(addr, size, _ebss_l2 - _stext_l2, L2_START, L2_LENGTH))
501                 return 1;
502
503         if (in_mem_const(addr, size, BOOT_ROM_START, BOOT_ROM_LENGTH))
504                 return 1;
505         if (in_mem_const(addr, size, L1_ROM_START, L1_ROM_LENGTH))
506                 return 1;
507
508         return 0;
509 }
510 EXPORT_SYMBOL(_access_ok);
511 #endif /* CONFIG_ACCESS_CHECK */