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