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 */