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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>
  34 #include <linux/a.out.h>
  35 #include <linux/uaccess.h>
  36 #include <linux/fs.h>
  37 #include <linux/err.h>
  38
  39 #include <asm/blackfin.h>
  40 #include <asm/fixed_code.h>
  41
  42 #define LED_ON  0
  43 #define LED_OFF 1
  44
  45 asmlinkage void ret_from_fork(void);
  46
  47 /* Points to the SDRAM backup memory for the stack that is currently in
  48  * L1 scratchpad memory.
  49  */
  50 void *current_l1_stack_save;
  51
  52 /* The number of tasks currently using a L1 stack area.  The SRAM is
  53  * allocated/deallocated whenever this changes from/to zero.
  54  */
  55 int nr_l1stack_tasks;
  56
  57 /* Start and length of the area in L1 scratchpad memory which we've allocated
  58  * for process stacks.
  59  */
  60 void *l1_stack_base;
  61 unsigned long l1_stack_len;
  62
  63 /*
  64  * Powermanagement idle function, if any..
  65  */
  66 void (*pm_idle)(void) = NULL;
  67 EXPORT_SYMBOL(pm_idle);
  68
  69 void (*pm_power_off)(void) = NULL;
  70 EXPORT_SYMBOL(pm_power_off);
  71
  72 /*
  73  * We are using a different LED from the one used to indicate timer interrupt.
  74  */
  75 #if defined(CONFIG_BFIN_IDLE_LED)
  76 static inline void leds_switch(int flag)
  77 {
  78         unsigned short tmp = 0;
  79
  80         tmp = bfin_read_CONFIG_BFIN_IDLE_LED_PORT();
  81         SSYNC();
  82
  83         if (flag == LED_ON)
  84                 tmp &= ~CONFIG_BFIN_IDLE_LED_PIN;       /* light on */
  85         else
  86                 tmp |= CONFIG_BFIN_IDLE_LED_PIN;        /* light off */
  87
  88         bfin_write_CONFIG_BFIN_IDLE_LED_PORT(tmp);
  89         SSYNC();
  90
  91 }
  92 #else
  93 static inline void leds_switch(int flag)
  94 {
  95 }
  96 #endif
  97
  98 /*
  99  * The idle loop on BFIN
 100  */
 101 #ifdef CONFIG_IDLE_L1
 102 void default_idle(void)__attribute__((l1_text));
 103 void cpu_idle(void)__attribute__((l1_text));
 104 #endif
 105
 106 void default_idle(void)
 107 {
 108         while (!need_resched()) {
 109                 leds_switch(LED_OFF);
 110                 local_irq_disable();
 111                 if (likely(!need_resched()))
 112                         idle_with_irq_disabled();
 113                 local_irq_enable();
 114                 leds_switch(LED_ON);
 115         }
 116 }
 117
 118 void (*idle)(void) = default_idle;
 119
 120 /*
 121  * The idle thread. There's no useful work to be
 122  * done, so just try to conserve power and have a
 123  * low exit latency (ie sit in a loop waiting for
 124  * somebody to say that they'd like to reschedule)
 125  */
 126 void cpu_idle(void)
 127 {
 128         /* endless idle loop with no priority at all */
 129         while (1) {
 130                 idle();
 131                 preempt_enable_no_resched();
 132                 schedule();
 133                 preempt_disable();
 134         }
 135 }
 136
 137 void show_regs(struct pt_regs *regs)
 138 {
 139         printk(KERN_NOTICE "\n");
 140         printk(KERN_NOTICE
 141                "PC: %08lu  Status: %04lu  SysStatus: %04lu  RETS: %08lu\n",
 142                regs->pc, regs->astat, regs->seqstat, regs->rets);
 143         printk(KERN_NOTICE
 144                "A0.x: %08lx  A0.w: %08lx  A1.x: %08lx  A1.w: %08lx\n",
 145                regs->a0x, regs->a0w, regs->a1x, regs->a1w);
 146         printk(KERN_NOTICE "P0: %08lx  P1: %08lx  P2: %08lx  P3: %08lx\n",
 147                regs->p0, regs->p1, regs->p2, regs->p3);
 148         printk(KERN_NOTICE "P4: %08lx  P5: %08lx\n", regs->p4, regs->p5);
 149         printk(KERN_NOTICE "R0: %08lx  R1: %08lx  R2: %08lx  R3: %08lx\n",
 150                regs->r0, regs->r1, regs->r2, regs->r3);
 151         printk(KERN_NOTICE "R4: %08lx  R5: %08lx  R6: %08lx  R7: %08lx\n",
 152                regs->r4, regs->r5, regs->r6, regs->r7);
 153
 154         if (!regs->ipend)
 155                 printk(KERN_NOTICE "USP: %08lx\n", rdusp());
 156 }
 157
 158 /* Fill in the fpu structure for a core dump.  */
 159
 160 int dump_fpu(struct pt_regs *regs, elf_fpregset_t * fpregs)
 161 {
 162         return 1;
 163 }
 164
 165 /*
 166  * This gets run with P1 containing the
 167  * function to call, and R1 containing
 168  * the "args".  Note P0 is clobbered on the way here.
 169  */
 170 void kernel_thread_helper(void);
 171 __asm__(".section .text\n"
 172         ".align 4\n"
 173         "_kernel_thread_helper:\n\t"
 174         "\tsp += -12;\n\t"
 175         "\tr0 = r1;\n\t" "\tcall (p1);\n\t" "\tcall _do_exit;\n" ".previous");
 176
 177 /*
 178  * Create a kernel thread.
 179  */
 180 pid_t kernel_thread(int (*fn) (void *), void *arg, unsigned long flags)
 181 {
 182         struct pt_regs regs;
 183
 184         memset(&regs, 0, sizeof(regs));
 185
 186         regs.r1 = (unsigned long)arg;
 187         regs.p1 = (unsigned long)fn;
 188         regs.pc = (unsigned long)kernel_thread_helper;
 189         regs.orig_p0 = -1;
 190         /* Set bit 2 to tell ret_from_fork we should be returning to kernel
 191            mode.  */
 192         regs.ipend = 0x8002;
 193         __asm__ __volatile__("%0 = syscfg;":"=da"(regs.syscfg):);
 194         return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL,
 195                        NULL);
 196 }
 197
 198 void flush_thread(void)
 199 {
 200 }
 201
 202 asmlinkage int bfin_vfork(struct pt_regs *regs)
 203 {
 204         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL,
 205                        NULL);
 206 }
 207
 208 asmlinkage int bfin_clone(struct pt_regs *regs)
 209 {
 210         unsigned long clone_flags;
 211         unsigned long newsp;
 212
 213         /* syscall2 puts clone_flags in r0 and usp in r1 */
 214         clone_flags = regs->r0;
 215         newsp = regs->r1;
 216         if (!newsp)
 217                 newsp = rdusp();
 218         else
 219                 newsp -= 12;
 220         return do_fork(clone_flags, newsp, regs, 0, NULL, NULL);
 221 }
 222
 223 int
 224 copy_thread(int nr, unsigned long clone_flags,
 225             unsigned long usp, unsigned long topstk,
 226             struct task_struct *p, struct pt_regs *regs)
 227 {
 228         struct pt_regs *childregs;
 229
 230         childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
 231         *childregs = *regs;
 232         childregs->r0 = 0;
 233
 234         p->thread.usp = usp;
 235         p->thread.ksp = (unsigned long)childregs;
 236         p->thread.pc = (unsigned long)ret_from_fork;
 237
 238         return 0;
 239 }
 240
 241 /*
 242  * sys_execve() executes a new program.
 243  */
 244
 245 asmlinkage int sys_execve(char *name, char **argv, char **envp)
 246 {
 247         int error;
 248         char *filename;
 249         struct pt_regs *regs = (struct pt_regs *)((&name) + 6);
 250
 251         lock_kernel();
 252         filename = getname(name);
 253         error = PTR_ERR(filename);
 254         if (IS_ERR(filename))
 255                 goto out;
 256         error = do_execve(filename, argv, envp, regs);
 257         putname(filename);
 258  out:
 259         unlock_kernel();
 260         return error;
 261 }
 262
 263 unsigned long get_wchan(struct task_struct *p)
 264 {
 265         unsigned long fp, pc;
 266         unsigned long stack_page;
 267         int count = 0;
 268         if (!p || p == current || p->state == TASK_RUNNING)
 269                 return 0;
 270
 271         stack_page = (unsigned long)p;
 272         fp = p->thread.usp;
 273         do {
 274                 if (fp < stack_page + sizeof(struct thread_info) ||
 275                     fp >= 8184 + stack_page)
 276                         return 0;
 277                 pc = ((unsigned long *)fp)[1];
 278                 if (!in_sched_functions(pc))
 279                         return pc;
 280                 fp = *(unsigned long *)fp;
 281         }
 282         while (count++ < 16);
 283         return 0;
 284 }
 285
 286 void finish_atomic_sections (struct pt_regs *regs)
 287 {
 288         if (regs->pc < ATOMIC_SEQS_START || regs->pc >= ATOMIC_SEQS_END)
 289                 return;
 290
 291         switch (regs->pc) {
 292         case ATOMIC_XCHG32 + 2:
 293                 put_user(regs->r1, (int *)regs->p0);
 294                 regs->pc += 2;
 295                 break;
 296
 297         case ATOMIC_CAS32 + 2:
 298         case ATOMIC_CAS32 + 4:
 299                 if (regs->r0 == regs->r1)
 300                         put_user(regs->r2, (int *)regs->p0);
 301                 regs->pc = ATOMIC_CAS32 + 8;
 302                 break;
 303         case ATOMIC_CAS32 + 6:
 304                 put_user(regs->r2, (int *)regs->p0);
 305                 regs->pc += 2;
 306                 break;
 307
 308         case ATOMIC_ADD32 + 2:
 309                 regs->r0 = regs->r1 + regs->r0;
 310                 /* fall through */
 311         case ATOMIC_ADD32 + 4:
 312                 put_user(regs->r0, (int *)regs->p0);
 313                 regs->pc = ATOMIC_ADD32 + 6;
 314                 break;
 315
 316         case ATOMIC_SUB32 + 2:
 317                 regs->r0 = regs->r1 - regs->r0;
 318                 /* fall through */
 319         case ATOMIC_SUB32 + 4:
 320                 put_user(regs->r0, (int *)regs->p0);
 321                 regs->pc = ATOMIC_SUB32 + 6;
 322                 break;
 323
 324         case ATOMIC_IOR32 + 2:
 325                 regs->r0 = regs->r1 | regs->r0;
 326                 /* fall through */
 327         case ATOMIC_IOR32 + 4:
 328                 put_user(regs->r0, (int *)regs->p0);
 329                 regs->pc = ATOMIC_IOR32 + 6;
 330                 break;
 331
 332         case ATOMIC_AND32 + 2:
 333                 regs->r0 = regs->r1 & regs->r0;
 334                 /* fall through */
 335         case ATOMIC_AND32 + 4:
 336                 put_user(regs->r0, (int *)regs->p0);
 337                 regs->pc = ATOMIC_AND32 + 6;
 338                 break;
 339
 340         case ATOMIC_XOR32 + 2:
 341                 regs->r0 = regs->r1 ^ regs->r0;
 342                 /* fall through */
 343         case ATOMIC_XOR32 + 4:
 344                 put_user(regs->r0, (int *)regs->p0);
 345                 regs->pc = ATOMIC_XOR32 + 6;
 346                 break;
 347         }
 348 }
 349
 350 #if defined(CONFIG_ACCESS_CHECK)
 351 int _access_ok(unsigned long addr, unsigned long size)
 352 {
 353         if (size == 0)
 354                 return 1;
 355         if (addr > (addr + size))
 356                 return 0;
 357         if (segment_eq(get_fs(), KERNEL_DS))
 358                 return 1;
 359 #ifdef CONFIG_MTD_UCLINUX
 360         if (addr >= memory_start && (addr + size) <= memory_end)
 361                 return 1;
 362         if (addr >= memory_mtd_end && (addr + size) <= physical_mem_end)
 363                 return 1;
 364 #else
 365         if (addr >= memory_start && (addr + size) <= physical_mem_end)
 366                 return 1;
 367 #endif
 368         if (addr >= (unsigned long)__init_begin &&
 369             addr + size <= (unsigned long)__init_end)
 370                 return 1;
 371         if (addr >= L1_SCRATCH_START
 372             && addr + size <= L1_SCRATCH_START + L1_SCRATCH_LENGTH)
 373                 return 1;
 374 #if L1_CODE_LENGTH != 0
 375         if (addr >= L1_CODE_START + (_etext_l1 - _stext_l1)
 376             && addr + size <= L1_CODE_START + L1_CODE_LENGTH)
 377                 return 1;
 378 #endif
 379 #if L1_DATA_A_LENGTH != 0
 380         if (addr >= L1_DATA_A_START + (_ebss_l1 - _sdata_l1)
 381             && addr + size <= L1_DATA_A_START + L1_DATA_A_LENGTH)
 382                 return 1;
 383 #endif
 384 #if L1_DATA_B_LENGTH != 0
 385         if (addr >= L1_DATA_B_START
 386             && addr + size <= L1_DATA_B_START + L1_DATA_B_LENGTH)
 387                 return 1;
 388 #endif
 389         return 0;
 390 }
 391 EXPORT_SYMBOL(_access_ok);
 392 #endif /* CONFIG_ACCESS_CHECK */