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 #include <asm/mem_map.h>
  43
  44 asmlinkage 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  */
  49 void *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  */
  54 int nr_l1stack_tasks;
  55
  56 /* Start and length of the area in L1 scratchpad memory which we've allocated
  57  * for process stacks.
  58  */
  59 void *l1_stack_base;
  60 unsigned long l1_stack_len;
  61
  62 /*
  63  * Powermanagement idle function, if any..
  64  */
  65 void (*pm_idle)(void) = NULL;
  66 EXPORT_SYMBOL(pm_idle);
  67
  68 void (*pm_power_off)(void) = NULL;
  69 EXPORT_SYMBOL(pm_power_off);
  70
  71 /*
  72  * The idle loop on BFIN
  73  */
  74 #ifdef CONFIG_IDLE_L1
  75 static void default_idle(void)__attribute__((l1_text));
  76 void cpu_idle(void)__attribute__((l1_text));
  77 #endif
  78
  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  */
  83 static void default_idle(void)
  84 {
  85 #ifdef CONFIG_IPIPE
  86         ipipe_suspend_domain();
  87 #endif
  88         local_irq_disable_hw();
  89         if (!need_resched())
  90                 idle_with_irq_disabled();
  91
  92         local_irq_enable_hw();
  93 }
  94
  95 /*
  96  * The idle thread.  We try to conserve power, while trying to keep
  97  * overall latency low.  The architecture specific idle is passed
  98  * a value to indicate the level of "idleness" of the system.
  99  */
 100 void cpu_idle(void)
 101 {
 102         /* endless idle loop with no priority at all */
 103         while (1) {
 104                 void (*idle)(void) = pm_idle;
 105
 106 #ifdef CONFIG_HOTPLUG_CPU
 107                 if (cpu_is_offline(smp_processor_id()))
 108                         cpu_die();
 109 #endif
 110                 if (!idle)
 111                         idle = default_idle;
 112                 tick_nohz_stop_sched_tick(1);
 113                 while (!need_resched())
 114                         idle();
 115                 tick_nohz_restart_sched_tick();
 116                 preempt_enable_no_resched();
 117                 schedule();
 118                 preempt_disable();
 119         }
 120 }
 121
 122 /* Fill in the fpu structure for a core dump.  */
 123
 124 int dump_fpu(struct pt_regs *regs, elf_fpregset_t * fpregs)
 125 {
 126         return 1;
 127 }
 128
 129 /*
 130  * This gets run with P1 containing the
 131  * function to call, and R1 containing
 132  * the "args".  Note P0 is clobbered on the way here.
 133  */
 134 void kernel_thread_helper(void);
 135 __asm__(".section .text\n"
 136         ".align 4\n"
 137         "_kernel_thread_helper:\n\t"
 138         "\tsp += -12;\n\t"
 139         "\tr0 = r1;\n\t" "\tcall (p1);\n\t" "\tcall _do_exit;\n" ".previous");
 140
 141 /*
 142  * Create a kernel thread.
 143  */
 144 pid_t kernel_thread(int (*fn) (void *), void *arg, unsigned long flags)
 145 {
 146         struct pt_regs regs;
 147
 148         memset(&regs, 0, sizeof(regs));
 149
 150         regs.r1 = (unsigned long)arg;
 151         regs.p1 = (unsigned long)fn;
 152         regs.pc = (unsigned long)kernel_thread_helper;
 153         regs.orig_p0 = -1;
 154         /* Set bit 2 to tell ret_from_fork we should be returning to kernel
 155            mode.  */
 156         regs.ipend = 0x8002;
 157         __asm__ __volatile__("%0 = syscfg;":"=da"(regs.syscfg):);
 158         return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL,
 159                        NULL);
 160 }
 161 EXPORT_SYMBOL(kernel_thread);
 162
 163 void flush_thread(void)
 164 {
 165 }
 166
 167 asmlinkage int bfin_vfork(struct pt_regs *regs)
 168 {
 169         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL,
 170                        NULL);
 171 }
 172
 173 asmlinkage int bfin_clone(struct pt_regs *regs)
 174 {
 175         unsigned long clone_flags;
 176         unsigned long newsp;
 177
 178 #ifdef __ARCH_SYNC_CORE_DCACHE
 179         if (current->rt.nr_cpus_allowed == num_possible_cpus()) {
 180                 current->cpus_allowed = cpumask_of_cpu(smp_processor_id());
 181                 current->rt.nr_cpus_allowed = 1;
 182         }
 183 #endif
 184
 185         /* syscall2 puts clone_flags in r0 and usp in r1 */
 186         clone_flags = regs->r0;
 187         newsp = regs->r1;
 188         if (!newsp)
 189                 newsp = rdusp();
 190         else
 191                 newsp -= 12;
 192         return do_fork(clone_flags, newsp, regs, 0, NULL, NULL);
 193 }
 194
 195 int
 196 copy_thread(unsigned long clone_flags,
 197             unsigned long usp, unsigned long topstk,
 198             struct task_struct *p, struct pt_regs *regs)
 199 {
 200         struct pt_regs *childregs;
 201
 202         childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
 203         *childregs = *regs;
 204         childregs->r0 = 0;
 205
 206         p->thread.usp = usp;
 207         p->thread.ksp = (unsigned long)childregs;
 208         p->thread.pc = (unsigned long)ret_from_fork;
 209
 210         return 0;
 211 }
 212
 213 /*
 214  * sys_execve() executes a new program.
 215  */
 216
 217 asmlinkage int sys_execve(char __user *name, char __user * __user *argv, char __user * __user *envp)
 218 {
 219         int error;
 220         char *filename;
 221         struct pt_regs *regs = (struct pt_regs *)((&name) + 6);
 222
 223         lock_kernel();
 224         filename = getname(name);
 225         error = PTR_ERR(filename);
 226         if (IS_ERR(filename))
 227                 goto out;
 228         error = do_execve(filename, argv, envp, regs);
 229         putname(filename);
 230  out:
 231         unlock_kernel();
 232         return error;
 233 }
 234
 235 unsigned long get_wchan(struct task_struct *p)
 236 {
 237         unsigned long fp, pc;
 238         unsigned long stack_page;
 239         int count = 0;
 240         if (!p || p == current || p->state == TASK_RUNNING)
 241                 return 0;
 242
 243         stack_page = (unsigned long)p;
 244         fp = p->thread.usp;
 245         do {
 246                 if (fp < stack_page + sizeof(struct thread_info) ||
 247                     fp >= 8184 + stack_page)
 248                         return 0;
 249                 pc = ((unsigned long *)fp)[1];
 250                 if (!in_sched_functions(pc))
 251                         return pc;
 252                 fp = *(unsigned long *)fp;
 253         }
 254         while (count++ < 16);
 255         return 0;
 256 }
 257
 258 void finish_atomic_sections (struct pt_regs *regs)
 259 {
 260         int __user *up0 = (int __user *)regs->p0;
 261
 262         if (regs->pc < ATOMIC_SEQS_START || regs->pc >= ATOMIC_SEQS_END)
 263                 return;
 264
 265         switch (regs->pc) {
 266         case ATOMIC_XCHG32 + 2:
 267                 put_user(regs->r1, up0);
 268                 regs->pc += 2;
 269                 break;
 270
 271         case ATOMIC_CAS32 + 2:
 272         case ATOMIC_CAS32 + 4:
 273                 if (regs->r0 == regs->r1)
 274                         put_user(regs->r2, up0);
 275                 regs->pc = ATOMIC_CAS32 + 8;
 276                 break;
 277         case ATOMIC_CAS32 + 6:
 278                 put_user(regs->r2, up0);
 279                 regs->pc += 2;
 280                 break;
 281
 282         case ATOMIC_ADD32 + 2:
 283                 regs->r0 = regs->r1 + regs->r0;
 284                 /* fall through */
 285         case ATOMIC_ADD32 + 4:
 286                 put_user(regs->r0, up0);
 287                 regs->pc = ATOMIC_ADD32 + 6;
 288                 break;
 289
 290         case ATOMIC_SUB32 + 2:
 291                 regs->r0 = regs->r1 - regs->r0;
 292                 /* fall through */
 293         case ATOMIC_SUB32 + 4:
 294                 put_user(regs->r0, up0);
 295                 regs->pc = ATOMIC_SUB32 + 6;
 296                 break;
 297
 298         case ATOMIC_IOR32 + 2:
 299                 regs->r0 = regs->r1 | regs->r0;
 300                 /* fall through */
 301         case ATOMIC_IOR32 + 4:
 302                 put_user(regs->r0, up0);
 303                 regs->pc = ATOMIC_IOR32 + 6;
 304                 break;
 305
 306         case ATOMIC_AND32 + 2:
 307                 regs->r0 = regs->r1 & regs->r0;
 308                 /* fall through */
 309         case ATOMIC_AND32 + 4:
 310                 put_user(regs->r0, up0);
 311                 regs->pc = ATOMIC_AND32 + 6;
 312                 break;
 313
 314         case ATOMIC_XOR32 + 2:
 315                 regs->r0 = regs->r1 ^ regs->r0;
 316                 /* fall through */
 317         case ATOMIC_XOR32 + 4:
 318                 put_user(regs->r0, up0);
 319                 regs->pc = ATOMIC_XOR32 + 6;
 320                 break;
 321         }
 322 }
 323
 324 #if defined(CONFIG_ACCESS_CHECK)
 325 /* Return 1 if access to memory range is OK, 0 otherwise */
 326 int _access_ok(unsigned long addr, unsigned long size)
 327 {
 328         if (size == 0)
 329                 return 1;
 330         if (addr > (addr + size))
 331                 return 0;
 332         if (segment_eq(get_fs(), KERNEL_DS))
 333                 return 1;
 334 #ifdef CONFIG_MTD_UCLINUX
 335         if (addr >= memory_start && (addr + size) <= memory_end)
 336                 return 1;
 337         if (addr >= memory_mtd_end && (addr + size) <= physical_mem_end)
 338                 return 1;
 339
 340 #ifdef CONFIG_ROMFS_ON_MTD
 341         /* For XIP, allow user space to use pointers within the ROMFS.  */
 342         if (addr >= memory_mtd_start && (addr + size) <= memory_mtd_end)
 343                 return 1;
 344 #endif
 345 #else
 346         if (addr >= memory_start && (addr + size) <= physical_mem_end)
 347                 return 1;
 348 #endif
 349         if (addr >= (unsigned long)__init_begin &&
 350             addr + size <= (unsigned long)__init_end)
 351                 return 1;
 352         if (addr >= get_l1_scratch_start()
 353             && addr + size <= get_l1_scratch_start() + L1_SCRATCH_LENGTH)
 354                 return 1;
 355 #if L1_CODE_LENGTH != 0
 356         if (addr >= get_l1_code_start() + (_etext_l1 - _stext_l1)
 357             && addr + size <= get_l1_code_start() + L1_CODE_LENGTH)
 358                 return 1;
 359 #endif
 360 #if L1_DATA_A_LENGTH != 0
 361         if (addr >= get_l1_data_a_start() + (_ebss_l1 - _sdata_l1)
 362             && addr + size <= get_l1_data_a_start() + L1_DATA_A_LENGTH)
 363                 return 1;
 364 #endif
 365 #if L1_DATA_B_LENGTH != 0
 366         if (addr >= get_l1_data_b_start() + (_ebss_b_l1 - _sdata_b_l1)
 367             && addr + size <= get_l1_data_b_start() + L1_DATA_B_LENGTH)
 368                 return 1;
 369 #endif
 370 #if L2_LENGTH != 0
 371         if (addr >= L2_START + (_ebss_l2 - _stext_l2)
 372             && addr + size <= L2_START + L2_LENGTH)
 373                 return 1;
 374 #endif
 375         return 0;
 376 }
 377 EXPORT_SYMBOL(_access_ok);
 378 #endif /* CONFIG_ACCESS_CHECK */