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/sched.h>
  36 #include <linux/tick.h>
  37 #include <linux/fs.h>
  38 #include <linux/err.h>
  39
  40 #include <asm/blackfin.h>
  41 #include <asm/fixed_code.h>
  42
  43 asmlinkage void ret_from_fork(void);
  44
  45 /* Points to the SDRAM backup memory for the stack that is currently in
  46  * L1 scratchpad memory.
  47  */
  48 void *current_l1_stack_save;
  49
  50 /* The number of tasks currently using a L1 stack area.  The SRAM is
  51  * allocated/deallocated whenever this changes from/to zero.
  52  */
  53 int nr_l1stack_tasks;
  54
  55 /* Start and length of the area in L1 scratchpad memory which we've allocated
  56  * for process stacks.
  57  */
  58 void *l1_stack_base;
  59 unsigned long l1_stack_len;
  60
  61 /*
  62  * Powermanagement idle function, if any..
  63  */
  64 void (*pm_idle)(void) = NULL;
  65 EXPORT_SYMBOL(pm_idle);
  66
  67 void (*pm_power_off)(void) = NULL;
  68 EXPORT_SYMBOL(pm_power_off);
  69
  70 /*
  71  * The idle loop on BFIN
  72  */
  73 #ifdef CONFIG_IDLE_L1
  74 static void default_idle(void)__attribute__((l1_text));
  75 void cpu_idle(void)__attribute__((l1_text));
  76 #endif
  77
  78 /*
  79  * This is our default idle handler.  We need to disable
  80  * interrupts here to ensure we don't miss a wakeup call.
  81  */
  82 static void default_idle(void)
  83 {
  84         local_irq_disable();
  85         if (!need_resched())
  86                 idle_with_irq_disabled();
  87
  88         local_irq_enable();
  89 }
  90
  91 /*
  92  * The idle thread.  We try to conserve power, while trying to keep
  93  * overall latency low.  The architecture specific idle is passed
  94  * a value to indicate the level of "idleness" of the system.
  95  */
  96 void cpu_idle(void)
  97 {
  98         /* endless idle loop with no priority at all */
  99         while (1) {
 100                 void (*idle)(void) = pm_idle;
 101
 102 #ifdef CONFIG_HOTPLUG_CPU
 103                 if (cpu_is_offline(smp_processor_id()))
 104                         cpu_die();
 105 #endif
 106                 if (!idle)
 107                         idle = default_idle;
 108                 tick_nohz_stop_sched_tick(1);
 109                 while (!need_resched())
 110                         idle();
 111                 tick_nohz_restart_sched_tick();
 112                 preempt_enable_no_resched();
 113                 schedule();
 114                 preempt_disable();
 115         }
 116 }
 117
 118 /* Fill in the fpu structure for a core dump.  */
 119
 120 int dump_fpu(struct pt_regs *regs, elf_fpregset_t * fpregs)
 121 {
 122         return 1;
 123 }
 124
 125 /*
 126  * This gets run with P1 containing the
 127  * function to call, and R1 containing
 128  * the "args".  Note P0 is clobbered on the way here.
 129  */
 130 void kernel_thread_helper(void);
 131 __asm__(".section .text\n"
 132         ".align 4\n"
 133         "_kernel_thread_helper:\n\t"
 134         "\tsp += -12;\n\t"
 135         "\tr0 = r1;\n\t" "\tcall (p1);\n\t" "\tcall _do_exit;\n" ".previous");
 136
 137 /*
 138  * Create a kernel thread.
 139  */
 140 pid_t kernel_thread(int (*fn) (void *), void *arg, unsigned long flags)
 141 {
 142         struct pt_regs regs;
 143
 144         memset(&regs, 0, sizeof(regs));
 145
 146         regs.r1 = (unsigned long)arg;
 147         regs.p1 = (unsigned long)fn;
 148         regs.pc = (unsigned long)kernel_thread_helper;
 149         regs.orig_p0 = -1;
 150         /* Set bit 2 to tell ret_from_fork we should be returning to kernel
 151            mode.  */
 152         regs.ipend = 0x8002;
 153         __asm__ __volatile__("%0 = syscfg;":"=da"(regs.syscfg):);
 154         return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL,
 155                        NULL);
 156 }
 157
 158 void flush_thread(void)
 159 {
 160 }
 161
 162 asmlinkage int bfin_vfork(struct pt_regs *regs)
 163 {
 164         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL,
 165                        NULL);
 166 }
 167
 168 asmlinkage int bfin_clone(struct pt_regs *regs)
 169 {
 170         unsigned long clone_flags;
 171         unsigned long newsp;
 172
 173         /* syscall2 puts clone_flags in r0 and usp in r1 */
 174         clone_flags = regs->r0;
 175         newsp = regs->r1;
 176         if (!newsp)
 177                 newsp = rdusp();
 178         else
 179                 newsp -= 12;
 180         return do_fork(clone_flags, newsp, regs, 0, NULL, NULL);
 181 }
 182
 183 int
 184 copy_thread(int nr, unsigned long clone_flags,
 185             unsigned long usp, unsigned long topstk,
 186             struct task_struct *p, struct pt_regs *regs)
 187 {
 188         struct pt_regs *childregs;
 189
 190         childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
 191         *childregs = *regs;
 192         childregs->r0 = 0;
 193
 194         p->thread.usp = usp;
 195         p->thread.ksp = (unsigned long)childregs;
 196         p->thread.pc = (unsigned long)ret_from_fork;
 197
 198         return 0;
 199 }
 200
 201 /*
 202  * sys_execve() executes a new program.
 203  */
 204
 205 asmlinkage int sys_execve(char __user *name, char __user * __user *argv, char __user * __user *envp)
 206 {
 207         int error;
 208         char *filename;
 209         struct pt_regs *regs = (struct pt_regs *)((&name) + 6);
 210
 211         lock_kernel();
 212         filename = getname(name);
 213         error = PTR_ERR(filename);
 214         if (IS_ERR(filename))
 215                 goto out;
 216         error = do_execve(filename, argv, envp, regs);
 217         putname(filename);
 218  out:
 219         unlock_kernel();
 220         return error;
 221 }
 222
 223 unsigned long get_wchan(struct task_struct *p)
 224 {
 225         unsigned long fp, pc;
 226         unsigned long stack_page;
 227         int count = 0;
 228         if (!p || p == current || p->state == TASK_RUNNING)
 229                 return 0;
 230
 231         stack_page = (unsigned long)p;
 232         fp = p->thread.usp;
 233         do {
 234                 if (fp < stack_page + sizeof(struct thread_info) ||
 235                     fp >= 8184 + stack_page)
 236                         return 0;
 237                 pc = ((unsigned long *)fp)[1];
 238                 if (!in_sched_functions(pc))
 239                         return pc;
 240                 fp = *(unsigned long *)fp;
 241         }
 242         while (count++ < 16);
 243         return 0;
 244 }
 245
 246 void finish_atomic_sections (struct pt_regs *regs)
 247 {
 248         int __user *up0 = (int __user *)regs->p0;
 249
 250         if (regs->pc < ATOMIC_SEQS_START || regs->pc >= ATOMIC_SEQS_END)
 251                 return;
 252
 253         switch (regs->pc) {
 254         case ATOMIC_XCHG32 + 2:
 255                 put_user(regs->r1, up0);
 256                 regs->pc += 2;
 257                 break;
 258
 259         case ATOMIC_CAS32 + 2:
 260         case ATOMIC_CAS32 + 4:
 261                 if (regs->r0 == regs->r1)
 262                         put_user(regs->r2, up0);
 263                 regs->pc = ATOMIC_CAS32 + 8;
 264                 break;
 265         case ATOMIC_CAS32 + 6:
 266                 put_user(regs->r2, up0);
 267                 regs->pc += 2;
 268                 break;
 269
 270         case ATOMIC_ADD32 + 2:
 271                 regs->r0 = regs->r1 + regs->r0;
 272                 /* fall through */
 273         case ATOMIC_ADD32 + 4:
 274                 put_user(regs->r0, up0);
 275                 regs->pc = ATOMIC_ADD32 + 6;
 276                 break;
 277
 278         case ATOMIC_SUB32 + 2:
 279                 regs->r0 = regs->r1 - regs->r0;
 280                 /* fall through */
 281         case ATOMIC_SUB32 + 4:
 282                 put_user(regs->r0, up0);
 283                 regs->pc = ATOMIC_SUB32 + 6;
 284                 break;
 285
 286         case ATOMIC_IOR32 + 2:
 287                 regs->r0 = regs->r1 | regs->r0;
 288                 /* fall through */
 289         case ATOMIC_IOR32 + 4:
 290                 put_user(regs->r0, up0);
 291                 regs->pc = ATOMIC_IOR32 + 6;
 292                 break;
 293
 294         case ATOMIC_AND32 + 2:
 295                 regs->r0 = regs->r1 & regs->r0;
 296                 /* fall through */
 297         case ATOMIC_AND32 + 4:
 298                 put_user(regs->r0, up0);
 299                 regs->pc = ATOMIC_AND32 + 6;
 300                 break;
 301
 302         case ATOMIC_XOR32 + 2:
 303                 regs->r0 = regs->r1 ^ regs->r0;
 304                 /* fall through */
 305         case ATOMIC_XOR32 + 4:
 306                 put_user(regs->r0, up0);
 307                 regs->pc = ATOMIC_XOR32 + 6;
 308                 break;
 309         }
 310 }
 311
 312 #if defined(CONFIG_ACCESS_CHECK)
 313 /* Return 1 if access to memory range is OK, 0 otherwise */
 314 int _access_ok(unsigned long addr, unsigned long size)
 315 {
 316         if (size == 0)
 317                 return 1;
 318         if (addr > (addr + size))
 319                 return 0;
 320         if (segment_eq(get_fs(), KERNEL_DS))
 321                 return 1;
 322 #ifdef CONFIG_MTD_UCLINUX
 323         if (addr >= memory_start && (addr + size) <= memory_end)
 324                 return 1;
 325         if (addr >= memory_mtd_end && (addr + size) <= physical_mem_end)
 326                 return 1;
 327
 328 #ifdef CONFIG_ROMFS_MTD_FS
 329         /* For XIP, allow user space to use pointers within the ROMFS.  */
 330         if (addr >= memory_mtd_start && (addr + size) <= memory_mtd_end)
 331                 return 1;
 332 #endif
 333 #else
 334         if (addr >= memory_start && (addr + size) <= physical_mem_end)
 335                 return 1;
 336 #endif
 337         if (addr >= (unsigned long)__init_begin &&
 338             addr + size <= (unsigned long)__init_end)
 339                 return 1;
 340         if (addr >= L1_SCRATCH_START
 341             && addr + size <= L1_SCRATCH_START + L1_SCRATCH_LENGTH)
 342                 return 1;
 343 #if L1_CODE_LENGTH != 0
 344         if (addr >= L1_CODE_START + (_etext_l1 - _stext_l1)
 345             && addr + size <= L1_CODE_START + L1_CODE_LENGTH)
 346                 return 1;
 347 #endif
 348 #if L1_DATA_A_LENGTH != 0
 349         if (addr >= L1_DATA_A_START + (_ebss_l1 - _sdata_l1)
 350             && addr + size <= L1_DATA_A_START + L1_DATA_A_LENGTH)
 351                 return 1;
 352 #endif
 353 #if L1_DATA_B_LENGTH != 0
 354         if (addr >= L1_DATA_B_START
 355             && addr + size <= L1_DATA_B_START + L1_DATA_B_LENGTH)
 356                 return 1;
 357 #endif
 358         return 0;
 359 }
 360 EXPORT_SYMBOL(_access_ok);
 361 #endif /* CONFIG_ACCESS_CHECK */