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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>
1f83b8f1 34#include <linux/uaccess.h>
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35#include <linux/sched.h>
36#include <linux/tick.h>
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37#include <linux/fs.h>
38#include <linux/err.h>
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39
40#include <asm/blackfin.h>
7adfb58f 41#include <asm/fixed_code.h>
dbc895f9 42#include <asm/mem_map.h>
1394f032 43
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44asmlinkage void ret_from_fork(void);
45
46/* Points to the SDRAM backup memory for the stack that is currently in
47 * L1 scratchpad memory.
48 */
49void *current_l1_stack_save;
50
51/* The number of tasks currently using a L1 stack area. The SRAM is
52 * allocated/deallocated whenever this changes from/to zero.
53 */
54int nr_l1stack_tasks;
55
56/* Start and length of the area in L1 scratchpad memory which we've allocated
57 * for process stacks.
58 */
59void *l1_stack_base;
60unsigned long l1_stack_len;
61
62/*
63 * Powermanagement idle function, if any..
64 */
65void (*pm_idle)(void) = NULL;
66EXPORT_SYMBOL(pm_idle);
67
68void (*pm_power_off)(void) = NULL;
69EXPORT_SYMBOL(pm_power_off);
70
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71/*
72 * The idle loop on BFIN
73 */
74#ifdef CONFIG_IDLE_L1
8b5f79f9 75static void default_idle(void)__attribute__((l1_text));
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76void cpu_idle(void)__attribute__((l1_text));
77#endif
78
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79/*
80 * This is our default idle handler. We need to disable
81 * interrupts here to ensure we don't miss a wakeup call.
82 */
83static void default_idle(void)
1394f032 84{
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85 local_irq_disable();
86 if (!need_resched())
87 idle_with_irq_disabled();
1394f032 88
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89 local_irq_enable();
90}
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91
92/*
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93 * The idle thread. We try to conserve power, while trying to keep
94 * overall latency low. The architecture specific idle is passed
95 * a value to indicate the level of "idleness" of the system.
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96 */
97void cpu_idle(void)
98{
99 /* endless idle loop with no priority at all */
100 while (1) {
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101 void (*idle)(void) = pm_idle;
102
103#ifdef CONFIG_HOTPLUG_CPU
104 if (cpu_is_offline(smp_processor_id()))
105 cpu_die();
106#endif
107 if (!idle)
108 idle = default_idle;
b8f8c3cf 109 tick_nohz_stop_sched_tick(1);
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110 while (!need_resched())
111 idle();
112 tick_nohz_restart_sched_tick();
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113 preempt_enable_no_resched();
114 schedule();
115 preempt_disable();
116 }
117}
118
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119/* Fill in the fpu structure for a core dump. */
120
121int dump_fpu(struct pt_regs *regs, elf_fpregset_t * fpregs)
122{
123 return 1;
124}
125
126/*
127 * This gets run with P1 containing the
128 * function to call, and R1 containing
129 * the "args". Note P0 is clobbered on the way here.
130 */
131void kernel_thread_helper(void);
132__asm__(".section .text\n"
133 ".align 4\n"
134 "_kernel_thread_helper:\n\t"
135 "\tsp += -12;\n\t"
136 "\tr0 = r1;\n\t" "\tcall (p1);\n\t" "\tcall _do_exit;\n" ".previous");
137
138/*
139 * Create a kernel thread.
140 */
141pid_t kernel_thread(int (*fn) (void *), void *arg, unsigned long flags)
142{
143 struct pt_regs regs;
144
145 memset(&regs, 0, sizeof(regs));
146
147 regs.r1 = (unsigned long)arg;
148 regs.p1 = (unsigned long)fn;
149 regs.pc = (unsigned long)kernel_thread_helper;
150 regs.orig_p0 = -1;
151 /* Set bit 2 to tell ret_from_fork we should be returning to kernel
152 mode. */
153 regs.ipend = 0x8002;
154 __asm__ __volatile__("%0 = syscfg;":"=da"(regs.syscfg):);
155 return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL,
156 NULL);
157}
fe8015ce 158EXPORT_SYMBOL(kernel_thread);
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159
160void flush_thread(void)
161{
162}
163
164asmlinkage int bfin_vfork(struct pt_regs *regs)
165{
166 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL,
167 NULL);
168}
169
170asmlinkage int bfin_clone(struct pt_regs *regs)
171{
172 unsigned long clone_flags;
173 unsigned long newsp;
174
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175#ifdef __ARCH_SYNC_CORE_DCACHE
176 if (current->rt.nr_cpus_allowed == num_possible_cpus()) {
177 current->cpus_allowed = cpumask_of_cpu(smp_processor_id());
178 current->rt.nr_cpus_allowed = 1;
179 }
180#endif
181
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182 /* syscall2 puts clone_flags in r0 and usp in r1 */
183 clone_flags = regs->r0;
184 newsp = regs->r1;
185 if (!newsp)
186 newsp = rdusp();
187 else
188 newsp -= 12;
189 return do_fork(clone_flags, newsp, regs, 0, NULL, NULL);
190}
191
192int
193copy_thread(int nr, unsigned long clone_flags,
194 unsigned long usp, unsigned long topstk,
195 struct task_struct *p, struct pt_regs *regs)
196{
197 struct pt_regs *childregs;
198
199 childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
200 *childregs = *regs;
201 childregs->r0 = 0;
202
203 p->thread.usp = usp;
204 p->thread.ksp = (unsigned long)childregs;
205 p->thread.pc = (unsigned long)ret_from_fork;
206
207 return 0;
208}
209
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210/*
211 * sys_execve() executes a new program.
212 */
213
0ddeeca2 214asmlinkage int sys_execve(char __user *name, char __user * __user *argv, char __user * __user *envp)
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215{
216 int error;
217 char *filename;
218 struct pt_regs *regs = (struct pt_regs *)((&name) + 6);
219
220 lock_kernel();
221 filename = getname(name);
222 error = PTR_ERR(filename);
223 if (IS_ERR(filename))
224 goto out;
225 error = do_execve(filename, argv, envp, regs);
226 putname(filename);
1f83b8f1 227 out:
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228 unlock_kernel();
229 return error;
230}
231
232unsigned long get_wchan(struct task_struct *p)
233{
234 unsigned long fp, pc;
235 unsigned long stack_page;
236 int count = 0;
237 if (!p || p == current || p->state == TASK_RUNNING)
238 return 0;
239
240 stack_page = (unsigned long)p;
241 fp = p->thread.usp;
242 do {
243 if (fp < stack_page + sizeof(struct thread_info) ||
244 fp >= 8184 + stack_page)
245 return 0;
246 pc = ((unsigned long *)fp)[1];
247 if (!in_sched_functions(pc))
248 return pc;
249 fp = *(unsigned long *)fp;
250 }
251 while (count++ < 16);
252 return 0;
253}
254
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255void finish_atomic_sections (struct pt_regs *regs)
256{
19d6d7d5 257 int __user *up0 = (int __user *)regs->p0;
0ddeeca2 258
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259 if (regs->pc < ATOMIC_SEQS_START || regs->pc >= ATOMIC_SEQS_END)
260 return;
261
262 switch (regs->pc) {
263 case ATOMIC_XCHG32 + 2:
0ddeeca2 264 put_user(regs->r1, up0);
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265 regs->pc += 2;
266 break;
267
268 case ATOMIC_CAS32 + 2:
269 case ATOMIC_CAS32 + 4:
270 if (regs->r0 == regs->r1)
0ddeeca2 271 put_user(regs->r2, up0);
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272 regs->pc = ATOMIC_CAS32 + 8;
273 break;
274 case ATOMIC_CAS32 + 6:
0ddeeca2 275 put_user(regs->r2, up0);
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276 regs->pc += 2;
277 break;
278
279 case ATOMIC_ADD32 + 2:
280 regs->r0 = regs->r1 + regs->r0;
281 /* fall through */
282 case ATOMIC_ADD32 + 4:
0ddeeca2 283 put_user(regs->r0, up0);
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284 regs->pc = ATOMIC_ADD32 + 6;
285 break;
286
287 case ATOMIC_SUB32 + 2:
288 regs->r0 = regs->r1 - regs->r0;
289 /* fall through */
290 case ATOMIC_SUB32 + 4:
0ddeeca2 291 put_user(regs->r0, up0);
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292 regs->pc = ATOMIC_SUB32 + 6;
293 break;
294
295 case ATOMIC_IOR32 + 2:
296 regs->r0 = regs->r1 | regs->r0;
297 /* fall through */
298 case ATOMIC_IOR32 + 4:
0ddeeca2 299 put_user(regs->r0, up0);
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300 regs->pc = ATOMIC_IOR32 + 6;
301 break;
302
303 case ATOMIC_AND32 + 2:
304 regs->r0 = regs->r1 & regs->r0;
305 /* fall through */
306 case ATOMIC_AND32 + 4:
0ddeeca2 307 put_user(regs->r0, up0);
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308 regs->pc = ATOMIC_AND32 + 6;
309 break;
310
311 case ATOMIC_XOR32 + 2:
312 regs->r0 = regs->r1 ^ regs->r0;
313 /* fall through */
314 case ATOMIC_XOR32 + 4:
0ddeeca2 315 put_user(regs->r0, up0);
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316 regs->pc = ATOMIC_XOR32 + 6;
317 break;
318 }
319}
320
1394f032 321#if defined(CONFIG_ACCESS_CHECK)
b03b08ba 322/* Return 1 if access to memory range is OK, 0 otherwise */
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323int _access_ok(unsigned long addr, unsigned long size)
324{
bc41bb11
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325 if (size == 0)
326 return 1;
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327 if (addr > (addr + size))
328 return 0;
1f83b8f1 329 if (segment_eq(get_fs(), KERNEL_DS))
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330 return 1;
331#ifdef CONFIG_MTD_UCLINUX
332 if (addr >= memory_start && (addr + size) <= memory_end)
333 return 1;
334 if (addr >= memory_mtd_end && (addr + size) <= physical_mem_end)
335 return 1;
d5adb029
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336
337#ifdef CONFIG_ROMFS_MTD_FS
338 /* For XIP, allow user space to use pointers within the ROMFS. */
339 if (addr >= memory_mtd_start && (addr + size) <= memory_mtd_end)
340 return 1;
341#endif
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342#else
343 if (addr >= memory_start && (addr + size) <= physical_mem_end)
344 return 1;
345#endif
346 if (addr >= (unsigned long)__init_begin &&
347 addr + size <= (unsigned long)__init_end)
348 return 1;
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349 if (addr >= get_l1_scratch_start()
350 && addr + size <= get_l1_scratch_start() + L1_SCRATCH_LENGTH)
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351 return 1;
352#if L1_CODE_LENGTH != 0
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353 if (addr >= get_l1_code_start() + (_etext_l1 - _stext_l1)
354 && addr + size <= get_l1_code_start() + L1_CODE_LENGTH)
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355 return 1;
356#endif
357#if L1_DATA_A_LENGTH != 0
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358 if (addr >= get_l1_data_a_start() + (_ebss_l1 - _sdata_l1)
359 && addr + size <= get_l1_data_a_start() + L1_DATA_A_LENGTH)
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360 return 1;
361#endif
362#if L1_DATA_B_LENGTH != 0
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363 if (addr >= get_l1_data_b_start() + (_ebss_b_l1 - _sdata_b_l1)
364 && addr + size <= get_l1_data_b_start() + L1_DATA_B_LENGTH)
1394f032 365 return 1;
b2c2f303
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366#endif
367#if L2_LENGTH != 0
368 if (addr >= L2_START + (_ebss_l2 - _stext_l2)
369 && addr + size <= L2_START + L2_LENGTH)
370 return 1;
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371#endif
372 return 0;
373}
374EXPORT_SYMBOL(_access_ok);
375#endif /* CONFIG_ACCESS_CHECK */