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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
  37 #include <asm/blackfin.h>
  38 #include <asm/fixed_code.h>
  39
  40 #define LED_ON  0
  41 #define LED_OFF 1
  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  * We are using a different LED from the one used to indicate timer interrupt.
  72  */
  73 #if defined(CONFIG_BFIN_IDLE_LED)
  74 static inline void leds_switch(int flag)
  75 {
  76         unsigned short tmp = 0;
  77
  78         tmp = bfin_read_CONFIG_BFIN_IDLE_LED_PORT();
  79         SSYNC();
  80
  81         if (flag == LED_ON)
  82                 tmp &= ~CONFIG_BFIN_IDLE_LED_PIN;       /* light on */
  83         else
  84                 tmp |= CONFIG_BFIN_IDLE_LED_PIN;        /* light off */
  85
  86         bfin_write_CONFIG_BFIN_IDLE_LED_PORT(tmp);
  87         SSYNC();
  88
  89 }
  90 #else
  91 static inline void leds_switch(int flag)
  92 {
  93 }
  94 #endif
  95
  96 /*
  97  * The idle loop on BFIN
  98  */
  99 #ifdef CONFIG_IDLE_L1
 100 void default_idle(void)__attribute__((l1_text));
 101 void cpu_idle(void)__attribute__((l1_text));
 102 #endif
 103
 104 void default_idle(void)
 105 {
 106         while (!need_resched()) {
 107                 leds_switch(LED_OFF);
 108                 local_irq_disable();
 109                 if (likely(!need_resched()))
 110                         idle_with_irq_disabled();
 111                 local_irq_enable();
 112                 leds_switch(LED_ON);
 113         }
 114 }
 115
 116 void (*idle)(void) = default_idle;
 117
 118 /*
 119  * The idle thread. There's no useful work to be
 120  * done, so just try to conserve power and have a
 121  * low exit latency (ie sit in a loop waiting for
 122  * somebody to say that they'd like to reschedule)
 123  */
 124 void cpu_idle(void)
 125 {
 126         /* endless idle loop with no priority at all */
 127         while (1) {
 128                 idle();
 129                 preempt_enable_no_resched();
 130                 schedule();
 131                 preempt_disable();
 132         }
 133 }
 134
 135 void machine_restart(char *__unused)
 136 {
 137 #if defined(CONFIG_BLKFIN_CACHE)
 138         bfin_write_IMEM_CONTROL(0x01);
 139         SSYNC();
 140 #endif
 141         bfin_reset();
 142         /* Dont do anything till the reset occurs */
 143         while (1) {
 144                 SSYNC();
 145         }
 146 }
 147
 148 void machine_halt(void)
 149 {
 150         for (;;)
 151                 asm volatile ("idle");
 152 }
 153
 154 void machine_power_off(void)
 155 {
 156         for (;;)
 157                 asm volatile ("idle");
 158 }
 159
 160 void show_regs(struct pt_regs *regs)
 161 {
 162         printk(KERN_NOTICE "\n");
 163         printk(KERN_NOTICE
 164                "PC: %08lu  Status: %04lu  SysStatus: %04lu  RETS: %08lu\n",
 165                regs->pc, regs->astat, regs->seqstat, regs->rets);
 166         printk(KERN_NOTICE
 167                "A0.x: %08lx  A0.w: %08lx  A1.x: %08lx  A1.w: %08lx\n",
 168                regs->a0x, regs->a0w, regs->a1x, regs->a1w);
 169         printk(KERN_NOTICE "P0: %08lx  P1: %08lx  P2: %08lx  P3: %08lx\n",
 170                regs->p0, regs->p1, regs->p2, regs->p3);
 171         printk(KERN_NOTICE "P4: %08lx  P5: %08lx\n", regs->p4, regs->p5);
 172         printk(KERN_NOTICE "R0: %08lx  R1: %08lx  R2: %08lx  R3: %08lx\n",
 173                regs->r0, regs->r1, regs->r2, regs->r3);
 174         printk(KERN_NOTICE "R4: %08lx  R5: %08lx  R6: %08lx  R7: %08lx\n",
 175                regs->r4, regs->r5, regs->r6, regs->r7);
 176
 177         if (!regs->ipend)
 178                 printk(KERN_NOTICE "USP: %08lx\n", rdusp());
 179 }
 180
 181 /* Fill in the fpu structure for a core dump.  */
 182
 183 int dump_fpu(struct pt_regs *regs, elf_fpregset_t * fpregs)
 184 {
 185         return 1;
 186 }
 187
 188 /*
 189  * This gets run with P1 containing the
 190  * function to call, and R1 containing
 191  * the "args".  Note P0 is clobbered on the way here.
 192  */
 193 void kernel_thread_helper(void);
 194 __asm__(".section .text\n"
 195         ".align 4\n"
 196         "_kernel_thread_helper:\n\t"
 197         "\tsp += -12;\n\t"
 198         "\tr0 = r1;\n\t" "\tcall (p1);\n\t" "\tcall _do_exit;\n" ".previous");
 199
 200 /*
 201  * Create a kernel thread.
 202  */
 203 pid_t kernel_thread(int (*fn) (void *), void *arg, unsigned long flags)
 204 {
 205         struct pt_regs regs;
 206
 207         memset(&regs, 0, sizeof(regs));
 208
 209         regs.r1 = (unsigned long)arg;
 210         regs.p1 = (unsigned long)fn;
 211         regs.pc = (unsigned long)kernel_thread_helper;
 212         regs.orig_p0 = -1;
 213         /* Set bit 2 to tell ret_from_fork we should be returning to kernel
 214            mode.  */
 215         regs.ipend = 0x8002;
 216         __asm__ __volatile__("%0 = syscfg;":"=da"(regs.syscfg):);
 217         return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL,
 218                        NULL);
 219 }
 220
 221 void flush_thread(void)
 222 {
 223 }
 224
 225 asmlinkage int bfin_vfork(struct pt_regs *regs)
 226 {
 227         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL,
 228                        NULL);
 229 }
 230
 231 asmlinkage int bfin_clone(struct pt_regs *regs)
 232 {
 233         unsigned long clone_flags;
 234         unsigned long newsp;
 235
 236         /* syscall2 puts clone_flags in r0 and usp in r1 */
 237         clone_flags = regs->r0;
 238         newsp = regs->r1;
 239         if (!newsp)
 240                 newsp = rdusp();
 241         else
 242                 newsp -= 12;
 243         return do_fork(clone_flags, newsp, regs, 0, NULL, NULL);
 244 }
 245
 246 int
 247 copy_thread(int nr, unsigned long clone_flags,
 248             unsigned long usp, unsigned long topstk,
 249             struct task_struct *p, struct pt_regs *regs)
 250 {
 251         struct pt_regs *childregs;
 252
 253         childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
 254         *childregs = *regs;
 255         childregs->r0 = 0;
 256
 257         p->thread.usp = usp;
 258         p->thread.ksp = (unsigned long)childregs;
 259         p->thread.pc = (unsigned long)ret_from_fork;
 260
 261         return 0;
 262 }
 263
 264 /*
 265  * fill in the user structure for a core dump..
 266  */
 267 void dump_thread(struct pt_regs *regs, struct user *dump)
 268 {
 269         dump->magic = CMAGIC;
 270         dump->start_code = 0;
 271         dump->start_stack = rdusp() & ~(PAGE_SIZE - 1);
 272         dump->u_tsize = ((unsigned long)current->mm->end_code) >> PAGE_SHIFT;
 273         dump->u_dsize = ((unsigned long)(current->mm->brk +
 274                                          (PAGE_SIZE - 1))) >> PAGE_SHIFT;
 275         dump->u_dsize -= dump->u_tsize;
 276         dump->u_ssize = 0;
 277
 278         if (dump->start_stack < TASK_SIZE)
 279                 dump->u_ssize =
 280                     ((unsigned long)(TASK_SIZE -
 281                                      dump->start_stack)) >> PAGE_SHIFT;
 282
 283         dump->u_ar0 = (struct user_regs_struct *)((int)&dump->regs - (int)dump);
 284
 285         dump->regs.r0 = regs->r0;
 286         dump->regs.r1 = regs->r1;
 287         dump->regs.r2 = regs->r2;
 288         dump->regs.r3 = regs->r3;
 289         dump->regs.r4 = regs->r4;
 290         dump->regs.r5 = regs->r5;
 291         dump->regs.r6 = regs->r6;
 292         dump->regs.r7 = regs->r7;
 293         dump->regs.p0 = regs->p0;
 294         dump->regs.p1 = regs->p1;
 295         dump->regs.p2 = regs->p2;
 296         dump->regs.p3 = regs->p3;
 297         dump->regs.p4 = regs->p4;
 298         dump->regs.p5 = regs->p5;
 299         dump->regs.orig_p0 = regs->orig_p0;
 300         dump->regs.a0w = regs->a0w;
 301         dump->regs.a1w = regs->a1w;
 302         dump->regs.a0x = regs->a0x;
 303         dump->regs.a1x = regs->a1x;
 304         dump->regs.rets = regs->rets;
 305         dump->regs.astat = regs->astat;
 306         dump->regs.pc = regs->pc;
 307 }
 308
 309 /*
 310  * sys_execve() executes a new program.
 311  */
 312
 313 asmlinkage int sys_execve(char *name, char **argv, char **envp)
 314 {
 315         int error;
 316         char *filename;
 317         struct pt_regs *regs = (struct pt_regs *)((&name) + 6);
 318
 319         lock_kernel();
 320         filename = getname(name);
 321         error = PTR_ERR(filename);
 322         if (IS_ERR(filename))
 323                 goto out;
 324         error = do_execve(filename, argv, envp, regs);
 325         putname(filename);
 326  out:
 327         unlock_kernel();
 328         return error;
 329 }
 330
 331 unsigned long get_wchan(struct task_struct *p)
 332 {
 333         unsigned long fp, pc;
 334         unsigned long stack_page;
 335         int count = 0;
 336         if (!p || p == current || p->state == TASK_RUNNING)
 337                 return 0;
 338
 339         stack_page = (unsigned long)p;
 340         fp = p->thread.usp;
 341         do {
 342                 if (fp < stack_page + sizeof(struct thread_info) ||
 343                     fp >= 8184 + stack_page)
 344                         return 0;
 345                 pc = ((unsigned long *)fp)[1];
 346                 if (!in_sched_functions(pc))
 347                         return pc;
 348                 fp = *(unsigned long *)fp;
 349         }
 350         while (count++ < 16);
 351         return 0;
 352 }
 353
 354 void finish_atomic_sections (struct pt_regs *regs)
 355 {
 356         if (regs->pc < ATOMIC_SEQS_START || regs->pc >= ATOMIC_SEQS_END)
 357                 return;
 358
 359         switch (regs->pc) {
 360         case ATOMIC_XCHG32 + 2:
 361                 put_user(regs->r1, (int *)regs->p0);
 362                 regs->pc += 2;
 363                 break;
 364
 365         case ATOMIC_CAS32 + 2:
 366         case ATOMIC_CAS32 + 4:
 367                 if (regs->r0 == regs->r1)
 368                         put_user(regs->r2, (int *)regs->p0);
 369                 regs->pc = ATOMIC_CAS32 + 8;
 370                 break;
 371         case ATOMIC_CAS32 + 6:
 372                 put_user(regs->r2, (int *)regs->p0);
 373                 regs->pc += 2;
 374                 break;
 375
 376         case ATOMIC_ADD32 + 2:
 377                 regs->r0 = regs->r1 + regs->r0;
 378                 /* fall through */
 379         case ATOMIC_ADD32 + 4:
 380                 put_user(regs->r0, (int *)regs->p0);
 381                 regs->pc = ATOMIC_ADD32 + 6;
 382                 break;
 383
 384         case ATOMIC_SUB32 + 2:
 385                 regs->r0 = regs->r1 - regs->r0;
 386                 /* fall through */
 387         case ATOMIC_SUB32 + 4:
 388                 put_user(regs->r0, (int *)regs->p0);
 389                 regs->pc = ATOMIC_SUB32 + 6;
 390                 break;
 391
 392         case ATOMIC_IOR32 + 2:
 393                 regs->r0 = regs->r1 | regs->r0;
 394                 /* fall through */
 395         case ATOMIC_IOR32 + 4:
 396                 put_user(regs->r0, (int *)regs->p0);
 397                 regs->pc = ATOMIC_IOR32 + 6;
 398                 break;
 399
 400         case ATOMIC_AND32 + 2:
 401                 regs->r0 = regs->r1 & regs->r0;
 402                 /* fall through */
 403         case ATOMIC_AND32 + 4:
 404                 put_user(regs->r0, (int *)regs->p0);
 405                 regs->pc = ATOMIC_AND32 + 6;
 406                 break;
 407
 408         case ATOMIC_XOR32 + 2:
 409                 regs->r0 = regs->r1 ^ regs->r0;
 410                 /* fall through */
 411         case ATOMIC_XOR32 + 4:
 412                 put_user(regs->r0, (int *)regs->p0);
 413                 regs->pc = ATOMIC_XOR32 + 6;
 414                 break;
 415         }
 416 }
 417
 418 #if defined(CONFIG_ACCESS_CHECK)
 419 int _access_ok(unsigned long addr, unsigned long size)
 420 {
 421
 422         if (addr > (addr + size))
 423                 return 0;
 424         if (segment_eq(get_fs(), KERNEL_DS))
 425                 return 1;
 426 #ifdef CONFIG_MTD_UCLINUX
 427         if (addr >= memory_start && (addr + size) <= memory_end)
 428                 return 1;
 429         if (addr >= memory_mtd_end && (addr + size) <= physical_mem_end)
 430                 return 1;
 431 #else
 432         if (addr >= memory_start && (addr + size) <= physical_mem_end)
 433                 return 1;
 434 #endif
 435         if (addr >= (unsigned long)__init_begin &&
 436             addr + size <= (unsigned long)__init_end)
 437                 return 1;
 438         if (addr >= L1_SCRATCH_START
 439             && addr + size <= L1_SCRATCH_START + L1_SCRATCH_LENGTH)
 440                 return 1;
 441 #if L1_CODE_LENGTH != 0
 442         if (addr >= L1_CODE_START + (_etext_l1 - _stext_l1)
 443             && addr + size <= L1_CODE_START + L1_CODE_LENGTH)
 444                 return 1;
 445 #endif
 446 #if L1_DATA_A_LENGTH != 0
 447         if (addr >= L1_DATA_A_START + (_ebss_l1 - _sdata_l1)
 448             && addr + size <= L1_DATA_A_START + L1_DATA_A_LENGTH)
 449                 return 1;
 450 #endif
 451 #if L1_DATA_B_LENGTH != 0
 452         if (addr >= L1_DATA_B_START
 453             && addr + size <= L1_DATA_B_START + L1_DATA_B_LENGTH)
 454                 return 1;
 455 #endif
 456         return 0;
 457 }
 458 EXPORT_SYMBOL(_access_ok);
 459 #endif /* CONFIG_ACCESS_CHECK */