Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6
[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/uaccess.h>
35 #include <linux/fs.h>
36 #include <linux/err.h>
37
38 #include <asm/blackfin.h>
39 #include <asm/fixed_code.h>
40
41 asmlinkage void ret_from_fork(void);
42
43 /* Points to the SDRAM backup memory for the stack that is currently in
44  * L1 scratchpad memory.
45  */
46 void *current_l1_stack_save;
47
48 /* The number of tasks currently using a L1 stack area.  The SRAM is
49  * allocated/deallocated whenever this changes from/to zero.
50  */
51 int nr_l1stack_tasks;
52
53 /* Start and length of the area in L1 scratchpad memory which we've allocated
54  * for process stacks.
55  */
56 void *l1_stack_base;
57 unsigned long l1_stack_len;
58
59 /*
60  * Powermanagement idle function, if any..
61  */
62 void (*pm_idle)(void) = NULL;
63 EXPORT_SYMBOL(pm_idle);
64
65 void (*pm_power_off)(void) = NULL;
66 EXPORT_SYMBOL(pm_power_off);
67
68 /*
69  * The idle loop on BFIN
70  */
71 #ifdef CONFIG_IDLE_L1
72 void default_idle(void)__attribute__((l1_text));
73 void cpu_idle(void)__attribute__((l1_text));
74 #endif
75
76 void default_idle(void)
77 {
78         while (!need_resched()) {
79                 local_irq_disable();
80                 if (likely(!need_resched()))
81                         idle_with_irq_disabled();
82                 local_irq_enable();
83         }
84 }
85
86 void (*idle)(void) = default_idle;
87
88 /*
89  * The idle thread. There's no useful work to be
90  * done, so just try to conserve power and have a
91  * low exit latency (ie sit in a loop waiting for
92  * somebody to say that they'd like to reschedule)
93  */
94 void cpu_idle(void)
95 {
96         /* endless idle loop with no priority at all */
97         while (1) {
98                 idle();
99                 preempt_enable_no_resched();
100                 schedule();
101                 preempt_disable();
102         }
103 }
104
105 /* Fill in the fpu structure for a core dump.  */
106
107 int dump_fpu(struct pt_regs *regs, elf_fpregset_t * fpregs)
108 {
109         return 1;
110 }
111
112 /*
113  * This gets run with P1 containing the
114  * function to call, and R1 containing
115  * the "args".  Note P0 is clobbered on the way here.
116  */
117 void kernel_thread_helper(void);
118 __asm__(".section .text\n"
119         ".align 4\n"
120         "_kernel_thread_helper:\n\t"
121         "\tsp += -12;\n\t"
122         "\tr0 = r1;\n\t" "\tcall (p1);\n\t" "\tcall _do_exit;\n" ".previous");
123
124 /*
125  * Create a kernel thread.
126  */
127 pid_t kernel_thread(int (*fn) (void *), void *arg, unsigned long flags)
128 {
129         struct pt_regs regs;
130
131         memset(&regs, 0, sizeof(regs));
132
133         regs.r1 = (unsigned long)arg;
134         regs.p1 = (unsigned long)fn;
135         regs.pc = (unsigned long)kernel_thread_helper;
136         regs.orig_p0 = -1;
137         /* Set bit 2 to tell ret_from_fork we should be returning to kernel
138            mode.  */
139         regs.ipend = 0x8002;
140         __asm__ __volatile__("%0 = syscfg;":"=da"(regs.syscfg):);
141         return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL,
142                        NULL);
143 }
144
145 void flush_thread(void)
146 {
147 }
148
149 asmlinkage int bfin_vfork(struct pt_regs *regs)
150 {
151         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL,
152                        NULL);
153 }
154
155 asmlinkage int bfin_clone(struct pt_regs *regs)
156 {
157         unsigned long clone_flags;
158         unsigned long newsp;
159
160         /* syscall2 puts clone_flags in r0 and usp in r1 */
161         clone_flags = regs->r0;
162         newsp = regs->r1;
163         if (!newsp)
164                 newsp = rdusp();
165         else
166                 newsp -= 12;
167         return do_fork(clone_flags, newsp, regs, 0, NULL, NULL);
168 }
169
170 int
171 copy_thread(int nr, unsigned long clone_flags,
172             unsigned long usp, unsigned long topstk,
173             struct task_struct *p, struct pt_regs *regs)
174 {
175         struct pt_regs *childregs;
176
177         childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
178         *childregs = *regs;
179         childregs->r0 = 0;
180
181         p->thread.usp = usp;
182         p->thread.ksp = (unsigned long)childregs;
183         p->thread.pc = (unsigned long)ret_from_fork;
184
185         return 0;
186 }
187
188 /*
189  * sys_execve() executes a new program.
190  */
191
192 asmlinkage int sys_execve(char *name, char **argv, char **envp)
193 {
194         int error;
195         char *filename;
196         struct pt_regs *regs = (struct pt_regs *)((&name) + 6);
197
198         lock_kernel();
199         filename = getname(name);
200         error = PTR_ERR(filename);
201         if (IS_ERR(filename))
202                 goto out;
203         error = do_execve(filename, argv, envp, regs);
204         putname(filename);
205  out:
206         unlock_kernel();
207         return error;
208 }
209
210 unsigned long get_wchan(struct task_struct *p)
211 {
212         unsigned long fp, pc;
213         unsigned long stack_page;
214         int count = 0;
215         if (!p || p == current || p->state == TASK_RUNNING)
216                 return 0;
217
218         stack_page = (unsigned long)p;
219         fp = p->thread.usp;
220         do {
221                 if (fp < stack_page + sizeof(struct thread_info) ||
222                     fp >= 8184 + stack_page)
223                         return 0;
224                 pc = ((unsigned long *)fp)[1];
225                 if (!in_sched_functions(pc))
226                         return pc;
227                 fp = *(unsigned long *)fp;
228         }
229         while (count++ < 16);
230         return 0;
231 }
232
233 void finish_atomic_sections (struct pt_regs *regs)
234 {
235         if (regs->pc < ATOMIC_SEQS_START || regs->pc >= ATOMIC_SEQS_END)
236                 return;
237
238         switch (regs->pc) {
239         case ATOMIC_XCHG32 + 2:
240                 put_user(regs->r1, (int *)regs->p0);
241                 regs->pc += 2;
242                 break;
243
244         case ATOMIC_CAS32 + 2:
245         case ATOMIC_CAS32 + 4:
246                 if (regs->r0 == regs->r1)
247                         put_user(regs->r2, (int *)regs->p0);
248                 regs->pc = ATOMIC_CAS32 + 8;
249                 break;
250         case ATOMIC_CAS32 + 6:
251                 put_user(regs->r2, (int *)regs->p0);
252                 regs->pc += 2;
253                 break;
254
255         case ATOMIC_ADD32 + 2:
256                 regs->r0 = regs->r1 + regs->r0;
257                 /* fall through */
258         case ATOMIC_ADD32 + 4:
259                 put_user(regs->r0, (int *)regs->p0);
260                 regs->pc = ATOMIC_ADD32 + 6;
261                 break;
262
263         case ATOMIC_SUB32 + 2:
264                 regs->r0 = regs->r1 - regs->r0;
265                 /* fall through */
266         case ATOMIC_SUB32 + 4:
267                 put_user(regs->r0, (int *)regs->p0);
268                 regs->pc = ATOMIC_SUB32 + 6;
269                 break;
270
271         case ATOMIC_IOR32 + 2:
272                 regs->r0 = regs->r1 | regs->r0;
273                 /* fall through */
274         case ATOMIC_IOR32 + 4:
275                 put_user(regs->r0, (int *)regs->p0);
276                 regs->pc = ATOMIC_IOR32 + 6;
277                 break;
278
279         case ATOMIC_AND32 + 2:
280                 regs->r0 = regs->r1 & regs->r0;
281                 /* fall through */
282         case ATOMIC_AND32 + 4:
283                 put_user(regs->r0, (int *)regs->p0);
284                 regs->pc = ATOMIC_AND32 + 6;
285                 break;
286
287         case ATOMIC_XOR32 + 2:
288                 regs->r0 = regs->r1 ^ regs->r0;
289                 /* fall through */
290         case ATOMIC_XOR32 + 4:
291                 put_user(regs->r0, (int *)regs->p0);
292                 regs->pc = ATOMIC_XOR32 + 6;
293                 break;
294         }
295 }
296
297 #if defined(CONFIG_ACCESS_CHECK)
298 /* Return 1 if access to memory range is OK, 0 otherwise */
299 int _access_ok(unsigned long addr, unsigned long size)
300 {
301         if (size == 0)
302                 return 1;
303         if (addr > (addr + size))
304                 return 0;
305         if (segment_eq(get_fs(), KERNEL_DS))
306                 return 1;
307 #ifdef CONFIG_MTD_UCLINUX
308         if (addr >= memory_start && (addr + size) <= memory_end)
309                 return 1;
310         if (addr >= memory_mtd_end && (addr + size) <= physical_mem_end)
311                 return 1;
312 #else
313         if (addr >= memory_start && (addr + size) <= physical_mem_end)
314                 return 1;
315 #endif
316         if (addr >= (unsigned long)__init_begin &&
317             addr + size <= (unsigned long)__init_end)
318                 return 1;
319         if (addr >= L1_SCRATCH_START
320             && addr + size <= L1_SCRATCH_START + L1_SCRATCH_LENGTH)
321                 return 1;
322 #if L1_CODE_LENGTH != 0
323         if (addr >= L1_CODE_START + (_etext_l1 - _stext_l1)
324             && addr + size <= L1_CODE_START + L1_CODE_LENGTH)
325                 return 1;
326 #endif
327 #if L1_DATA_A_LENGTH != 0
328         if (addr >= L1_DATA_A_START + (_ebss_l1 - _sdata_l1)
329             && addr + size <= L1_DATA_A_START + L1_DATA_A_LENGTH)
330                 return 1;
331 #endif
332 #if L1_DATA_B_LENGTH != 0
333         if (addr >= L1_DATA_B_START
334             && addr + size <= L1_DATA_B_START + L1_DATA_B_LENGTH)
335                 return 1;
336 #endif
337         return 0;
338 }
339 EXPORT_SYMBOL(_access_ok);
340 #endif /* CONFIG_ACCESS_CHECK */