Merge branches 'release', 'misc' and 'misc-2.6.25' into release
[linux-2.6] / arch / blackfin / kernel / process.c
1 /*
2  * File:         arch/blackfin/kernel/process.c
3  * Based on:
4  * Author:
5  *
6  * Created:
7  * Description:  Blackfin architecture-dependent process handling.
8  *
9  * Modified:
10  *               Copyright 2004-2006 Analog Devices Inc.
11  *
12  * Bugs:         Enter bugs at http://blackfin.uclinux.org/
13  *
14  * This program is free software; you can redistribute it and/or modify
15  * it under the terms of the GNU General Public License as published by
16  * the Free Software Foundation; either version 2 of the License, or
17  * (at your option) any later version.
18  *
19  * This program is distributed in the hope that it will be useful,
20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
22  * GNU General Public License for more details.
23  *
24  * You should have received a copy of the GNU General Public License
25  * along with this program; if not, see the file COPYING, or write
26  * to the Free Software Foundation, Inc.,
27  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
28  */
29
30 #include <linux/module.h>
31 #include <linux/smp_lock.h>
32 #include <linux/unistd.h>
33 #include <linux/user.h>
34 #include <linux/a.out.h>
35 #include <linux/uaccess.h>
36 #include <linux/fs.h>
37 #include <linux/err.h>
38
39 #include <asm/blackfin.h>
40 #include <asm/fixed_code.h>
41
42 asmlinkage void ret_from_fork(void);
43
44 /* Points to the SDRAM backup memory for the stack that is currently in
45  * L1 scratchpad memory.
46  */
47 void *current_l1_stack_save;
48
49 /* The number of tasks currently using a L1 stack area.  The SRAM is
50  * allocated/deallocated whenever this changes from/to zero.
51  */
52 int nr_l1stack_tasks;
53
54 /* Start and length of the area in L1 scratchpad memory which we've allocated
55  * for process stacks.
56  */
57 void *l1_stack_base;
58 unsigned long l1_stack_len;
59
60 /*
61  * Powermanagement idle function, if any..
62  */
63 void (*pm_idle)(void) = NULL;
64 EXPORT_SYMBOL(pm_idle);
65
66 void (*pm_power_off)(void) = NULL;
67 EXPORT_SYMBOL(pm_power_off);
68
69 /*
70  * The idle loop on BFIN
71  */
72 #ifdef CONFIG_IDLE_L1
73 void default_idle(void)__attribute__((l1_text));
74 void cpu_idle(void)__attribute__((l1_text));
75 #endif
76
77 void default_idle(void)
78 {
79         while (!need_resched()) {
80                 local_irq_disable();
81                 if (likely(!need_resched()))
82                         idle_with_irq_disabled();
83                 local_irq_enable();
84         }
85 }
86
87 void (*idle)(void) = default_idle;
88
89 /*
90  * The idle thread. There's no useful work to be
91  * done, so just try to conserve power and have a
92  * low exit latency (ie sit in a loop waiting for
93  * somebody to say that they'd like to reschedule)
94  */
95 void cpu_idle(void)
96 {
97         /* endless idle loop with no priority at all */
98         while (1) {
99                 idle();
100                 preempt_enable_no_resched();
101                 schedule();
102                 preempt_disable();
103         }
104 }
105
106 /* Fill in the fpu structure for a core dump.  */
107
108 int dump_fpu(struct pt_regs *regs, elf_fpregset_t * fpregs)
109 {
110         return 1;
111 }
112
113 /*
114  * This gets run with P1 containing the
115  * function to call, and R1 containing
116  * the "args".  Note P0 is clobbered on the way here.
117  */
118 void kernel_thread_helper(void);
119 __asm__(".section .text\n"
120         ".align 4\n"
121         "_kernel_thread_helper:\n\t"
122         "\tsp += -12;\n\t"
123         "\tr0 = r1;\n\t" "\tcall (p1);\n\t" "\tcall _do_exit;\n" ".previous");
124
125 /*
126  * Create a kernel thread.
127  */
128 pid_t kernel_thread(int (*fn) (void *), void *arg, unsigned long flags)
129 {
130         struct pt_regs regs;
131
132         memset(&regs, 0, sizeof(regs));
133
134         regs.r1 = (unsigned long)arg;
135         regs.p1 = (unsigned long)fn;
136         regs.pc = (unsigned long)kernel_thread_helper;
137         regs.orig_p0 = -1;
138         /* Set bit 2 to tell ret_from_fork we should be returning to kernel
139            mode.  */
140         regs.ipend = 0x8002;
141         __asm__ __volatile__("%0 = syscfg;":"=da"(regs.syscfg):);
142         return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL,
143                        NULL);
144 }
145
146 void flush_thread(void)
147 {
148 }
149
150 asmlinkage int bfin_vfork(struct pt_regs *regs)
151 {
152         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL,
153                        NULL);
154 }
155
156 asmlinkage int bfin_clone(struct pt_regs *regs)
157 {
158         unsigned long clone_flags;
159         unsigned long newsp;
160
161         /* syscall2 puts clone_flags in r0 and usp in r1 */
162         clone_flags = regs->r0;
163         newsp = regs->r1;
164         if (!newsp)
165                 newsp = rdusp();
166         else
167                 newsp -= 12;
168         return do_fork(clone_flags, newsp, regs, 0, NULL, NULL);
169 }
170
171 int
172 copy_thread(int nr, unsigned long clone_flags,
173             unsigned long usp, unsigned long topstk,
174             struct task_struct *p, struct pt_regs *regs)
175 {
176         struct pt_regs *childregs;
177
178         childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
179         *childregs = *regs;
180         childregs->r0 = 0;
181
182         p->thread.usp = usp;
183         p->thread.ksp = (unsigned long)childregs;
184         p->thread.pc = (unsigned long)ret_from_fork;
185
186         return 0;
187 }
188
189 /*
190  * sys_execve() executes a new program.
191  */
192
193 asmlinkage int sys_execve(char *name, char **argv, char **envp)
194 {
195         int error;
196         char *filename;
197         struct pt_regs *regs = (struct pt_regs *)((&name) + 6);
198
199         lock_kernel();
200         filename = getname(name);
201         error = PTR_ERR(filename);
202         if (IS_ERR(filename))
203                 goto out;
204         error = do_execve(filename, argv, envp, regs);
205         putname(filename);
206  out:
207         unlock_kernel();
208         return error;
209 }
210
211 unsigned long get_wchan(struct task_struct *p)
212 {
213         unsigned long fp, pc;
214         unsigned long stack_page;
215         int count = 0;
216         if (!p || p == current || p->state == TASK_RUNNING)
217                 return 0;
218
219         stack_page = (unsigned long)p;
220         fp = p->thread.usp;
221         do {
222                 if (fp < stack_page + sizeof(struct thread_info) ||
223                     fp >= 8184 + stack_page)
224                         return 0;
225                 pc = ((unsigned long *)fp)[1];
226                 if (!in_sched_functions(pc))
227                         return pc;
228                 fp = *(unsigned long *)fp;
229         }
230         while (count++ < 16);
231         return 0;
232 }
233
234 void finish_atomic_sections (struct pt_regs *regs)
235 {
236         if (regs->pc < ATOMIC_SEQS_START || regs->pc >= ATOMIC_SEQS_END)
237                 return;
238
239         switch (regs->pc) {
240         case ATOMIC_XCHG32 + 2:
241                 put_user(regs->r1, (int *)regs->p0);
242                 regs->pc += 2;
243                 break;
244
245         case ATOMIC_CAS32 + 2:
246         case ATOMIC_CAS32 + 4:
247                 if (regs->r0 == regs->r1)
248                         put_user(regs->r2, (int *)regs->p0);
249                 regs->pc = ATOMIC_CAS32 + 8;
250                 break;
251         case ATOMIC_CAS32 + 6:
252                 put_user(regs->r2, (int *)regs->p0);
253                 regs->pc += 2;
254                 break;
255
256         case ATOMIC_ADD32 + 2:
257                 regs->r0 = regs->r1 + regs->r0;
258                 /* fall through */
259         case ATOMIC_ADD32 + 4:
260                 put_user(regs->r0, (int *)regs->p0);
261                 regs->pc = ATOMIC_ADD32 + 6;
262                 break;
263
264         case ATOMIC_SUB32 + 2:
265                 regs->r0 = regs->r1 - regs->r0;
266                 /* fall through */
267         case ATOMIC_SUB32 + 4:
268                 put_user(regs->r0, (int *)regs->p0);
269                 regs->pc = ATOMIC_SUB32 + 6;
270                 break;
271
272         case ATOMIC_IOR32 + 2:
273                 regs->r0 = regs->r1 | regs->r0;
274                 /* fall through */
275         case ATOMIC_IOR32 + 4:
276                 put_user(regs->r0, (int *)regs->p0);
277                 regs->pc = ATOMIC_IOR32 + 6;
278                 break;
279
280         case ATOMIC_AND32 + 2:
281                 regs->r0 = regs->r1 & regs->r0;
282                 /* fall through */
283         case ATOMIC_AND32 + 4:
284                 put_user(regs->r0, (int *)regs->p0);
285                 regs->pc = ATOMIC_AND32 + 6;
286                 break;
287
288         case ATOMIC_XOR32 + 2:
289                 regs->r0 = regs->r1 ^ regs->r0;
290                 /* fall through */
291         case ATOMIC_XOR32 + 4:
292                 put_user(regs->r0, (int *)regs->p0);
293                 regs->pc = ATOMIC_XOR32 + 6;
294                 break;
295         }
296 }
297
298 #if defined(CONFIG_ACCESS_CHECK)
299 /* Return 1 if access to memory range is OK, 0 otherwise */
300 int _access_ok(unsigned long addr, unsigned long size)
301 {
302         if (size == 0)
303                 return 1;
304         if (addr > (addr + size))
305                 return 0;
306         if (segment_eq(get_fs(), KERNEL_DS))
307                 return 1;
308 #ifdef CONFIG_MTD_UCLINUX
309         if (addr >= memory_start && (addr + size) <= memory_end)
310                 return 1;
311         if (addr >= memory_mtd_end && (addr + size) <= physical_mem_end)
312                 return 1;
313 #else
314         if (addr >= memory_start && (addr + size) <= physical_mem_end)
315                 return 1;
316 #endif
317         if (addr >= (unsigned long)__init_begin &&
318             addr + size <= (unsigned long)__init_end)
319                 return 1;
320         if (addr >= L1_SCRATCH_START
321             && addr + size <= L1_SCRATCH_START + L1_SCRATCH_LENGTH)
322                 return 1;
323 #if L1_CODE_LENGTH != 0
324         if (addr >= L1_CODE_START + (_etext_l1 - _stext_l1)
325             && addr + size <= L1_CODE_START + L1_CODE_LENGTH)
326                 return 1;
327 #endif
328 #if L1_DATA_A_LENGTH != 0
329         if (addr >= L1_DATA_A_START + (_ebss_l1 - _sdata_l1)
330             && addr + size <= L1_DATA_A_START + L1_DATA_A_LENGTH)
331                 return 1;
332 #endif
333 #if L1_DATA_B_LENGTH != 0
334         if (addr >= L1_DATA_B_START
335             && addr + size <= L1_DATA_B_START + L1_DATA_B_LENGTH)
336                 return 1;
337 #endif
338         return 0;
339 }
340 EXPORT_SYMBOL(_access_ok);
341 #endif /* CONFIG_ACCESS_CHECK */