arch/sh/kernel/process.c

   1 /*
   2  * arch/sh/kernel/process.c
   3  *
   4  * This file handles the architecture-dependent parts of process handling..
   5  *
   6  *  Copyright (C) 1995  Linus Torvalds
   7  *
   8  *  SuperH version:  Copyright (C) 1999, 2000  Niibe Yutaka & Kaz Kojima
   9  *                   Copyright (C) 2006 Lineo Solutions Inc. support SH4A UBC
  10  *                   Copyright (C) 2002 - 2007  Paul Mundt
  11  */
  12 #include <linux/module.h>
  13 #include <linux/mm.h>
  14 #include <linux/elfcore.h>
  15 #include <linux/pm.h>
  16 #include <linux/kallsyms.h>
  17 #include <linux/kexec.h>
  18 #include <linux/kdebug.h>
  19 #include <asm/uaccess.h>
  20 #include <asm/mmu_context.h>
  21 #include <asm/pgalloc.h>
  22 #include <asm/system.h>
  23 #include <asm/ubc.h>
  24
  25 static int hlt_counter;
  26 int ubc_usercnt = 0;
  27
  28 #define HARD_IDLE_TIMEOUT (HZ / 3)
  29
  30 void (*pm_idle)(void);
  31 void (*pm_power_off)(void);
  32 EXPORT_SYMBOL(pm_power_off);
  33
  34 void disable_hlt(void)
  35 {
  36         hlt_counter++;
  37 }
  38 EXPORT_SYMBOL(disable_hlt);
  39
  40 void enable_hlt(void)
  41 {
  42         hlt_counter--;
  43 }
  44 EXPORT_SYMBOL(enable_hlt);
  45
  46 void default_idle(void)
  47 {
  48         if (!hlt_counter)
  49                 cpu_sleep();
  50         else
  51                 cpu_relax();
  52 }
  53
  54 void cpu_idle(void)
  55 {
  56         /* endless idle loop with no priority at all */
  57         while (1) {
  58                 void (*idle)(void) = pm_idle;
  59
  60                 if (!idle)
  61                         idle = default_idle;
  62
  63                 while (!need_resched())
  64                         idle();
  65
  66                 preempt_enable_no_resched();
  67                 schedule();
  68                 preempt_disable();
  69                 check_pgt_cache();
  70         }
  71 }
  72
  73 void machine_restart(char * __unused)
  74 {
  75         /* SR.BL=1 and invoke address error to let CPU reset (manual reset) */
  76         asm volatile("ldc %0, sr\n\t"
  77                      "mov.l @%1, %0" : : "r" (0x10000000), "r" (0x80000001));
  78 }
  79
  80 void machine_halt(void)
  81 {
  82         local_irq_disable();
  83
  84         while (1)
  85                 cpu_sleep();
  86 }
  87
  88 void machine_power_off(void)
  89 {
  90         if (pm_power_off)
  91                 pm_power_off();
  92 }
  93
  94 void show_regs(struct pt_regs * regs)
  95 {
  96         printk("\n");
  97         printk("Pid : %d, Comm: %20s\n", current->pid, current->comm);
  98         print_symbol("PC is at %s\n", instruction_pointer(regs));
  99         printk("PC  : %08lx SP  : %08lx SR  : %08lx ",
 100                regs->pc, regs->regs[15], regs->sr);
 101 #ifdef CONFIG_MMU
 102         printk("TEA : %08x    ", ctrl_inl(MMU_TEA));
 103 #else
 104         printk("                  ");
 105 #endif
 106         printk("%s\n", print_tainted());
 107
 108         printk("R0  : %08lx R1  : %08lx R2  : %08lx R3  : %08lx\n",
 109                regs->regs[0],regs->regs[1],
 110                regs->regs[2],regs->regs[3]);
 111         printk("R4  : %08lx R5  : %08lx R6  : %08lx R7  : %08lx\n",
 112                regs->regs[4],regs->regs[5],
 113                regs->regs[6],regs->regs[7]);
 114         printk("R8  : %08lx R9  : %08lx R10 : %08lx R11 : %08lx\n",
 115                regs->regs[8],regs->regs[9],
 116                regs->regs[10],regs->regs[11]);
 117         printk("R12 : %08lx R13 : %08lx R14 : %08lx\n",
 118                regs->regs[12],regs->regs[13],
 119                regs->regs[14]);
 120         printk("MACH: %08lx MACL: %08lx GBR : %08lx PR  : %08lx\n",
 121                regs->mach, regs->macl, regs->gbr, regs->pr);
 122
 123         show_trace(NULL, (unsigned long *)regs->regs[15], regs);
 124 }
 125
 126 /*
 127  * Create a kernel thread
 128  */
 129
 130 /*
 131  * This is the mechanism for creating a new kernel thread.
 132  *
 133  */
 134 extern void kernel_thread_helper(void);
 135 __asm__(".align 5\n"
 136         "kernel_thread_helper:\n\t"
 137         "jsr    @r5\n\t"
 138         " nop\n\t"
 139         "mov.l  1f, r1\n\t"
 140         "jsr    @r1\n\t"
 141         " mov   r0, r4\n\t"
 142         ".align 2\n\t"
 143         "1:.long do_exit");
 144
 145 /* Don't use this in BL=1(cli).  Or else, CPU resets! */
 146 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 147 {
 148         struct pt_regs regs;
 149
 150         memset(&regs, 0, sizeof(regs));
 151         regs.regs[4] = (unsigned long)arg;
 152         regs.regs[5] = (unsigned long)fn;
 153
 154         regs.pc = (unsigned long)kernel_thread_helper;
 155         regs.sr = (1 << 30);
 156
 157         /* Ok, create the new process.. */
 158         return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
 159                        &regs, 0, NULL, NULL);
 160 }
 161
 162 /*
 163  * Free current thread data structures etc..
 164  */
 165 void exit_thread(void)
 166 {
 167         if (current->thread.ubc_pc) {
 168                 current->thread.ubc_pc = 0;
 169                 ubc_usercnt -= 1;
 170         }
 171 }
 172
 173 void flush_thread(void)
 174 {
 175 #if defined(CONFIG_SH_FPU)
 176         struct task_struct *tsk = current;
 177         /* Forget lazy FPU state */
 178         clear_fpu(tsk, task_pt_regs(tsk));
 179         clear_used_math();
 180 #endif
 181 }
 182
 183 void release_thread(struct task_struct *dead_task)
 184 {
 185         /* do nothing */
 186 }
 187
 188 /* Fill in the fpu structure for a core dump.. */
 189 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 190 {
 191         int fpvalid = 0;
 192
 193 #if defined(CONFIG_SH_FPU)
 194         struct task_struct *tsk = current;
 195
 196         fpvalid = !!tsk_used_math(tsk);
 197         if (fpvalid) {
 198                 unlazy_fpu(tsk, regs);
 199                 memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu));
 200         }
 201 #endif
 202
 203         return fpvalid;
 204 }
 205
 206 /*
 207  * Capture the user space registers if the task is not running (in user space)
 208  */
 209 int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
 210 {
 211         struct pt_regs ptregs;
 212
 213         ptregs = *task_pt_regs(tsk);
 214         elf_core_copy_regs(regs, &ptregs);
 215
 216         return 1;
 217 }
 218
 219 int dump_task_fpu(struct task_struct *tsk, elf_fpregset_t *fpu)
 220 {
 221         int fpvalid = 0;
 222
 223 #if defined(CONFIG_SH_FPU)
 224         fpvalid = !!tsk_used_math(tsk);
 225         if (fpvalid) {
 226                 unlazy_fpu(tsk, task_pt_regs(tsk));
 227                 memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu));
 228         }
 229 #endif
 230
 231         return fpvalid;
 232 }
 233
 234 asmlinkage void ret_from_fork(void);
 235
 236 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 237                 unsigned long unused,
 238                 struct task_struct *p, struct pt_regs *regs)
 239 {
 240         struct thread_info *ti = task_thread_info(p);
 241         struct pt_regs *childregs;
 242 #if defined(CONFIG_SH_FPU)
 243         struct task_struct *tsk = current;
 244
 245         unlazy_fpu(tsk, regs);
 246         p->thread.fpu = tsk->thread.fpu;
 247         copy_to_stopped_child_used_math(p);
 248 #endif
 249
 250         childregs = task_pt_regs(p);
 251         *childregs = *regs;
 252
 253         if (user_mode(regs)) {
 254                 childregs->regs[15] = usp;
 255                 ti->addr_limit = USER_DS;
 256         } else {
 257                 childregs->regs[15] = (unsigned long)childregs;
 258                 ti->addr_limit = KERNEL_DS;
 259         }
 260
 261         if (clone_flags & CLONE_SETTLS)
 262                 childregs->gbr = childregs->regs[0];
 263
 264         childregs->regs[0] = 0; /* Set return value for child */
 265
 266         p->thread.sp = (unsigned long) childregs;
 267         p->thread.pc = (unsigned long) ret_from_fork;
 268
 269         p->thread.ubc_pc = 0;
 270
 271         return 0;
 272 }
 273
 274 /* Tracing by user break controller.  */
 275 static void ubc_set_tracing(int asid, unsigned long pc)
 276 {
 277 #if defined(CONFIG_CPU_SH4A)
 278         unsigned long val;
 279
 280         val = (UBC_CBR_ID_INST | UBC_CBR_RW_READ | UBC_CBR_CE);
 281         val |= (UBC_CBR_AIE | UBC_CBR_AIV_SET(asid));
 282
 283         ctrl_outl(val, UBC_CBR0);
 284         ctrl_outl(pc,  UBC_CAR0);
 285         ctrl_outl(0x0, UBC_CAMR0);
 286         ctrl_outl(0x0, UBC_CBCR);
 287
 288         val = (UBC_CRR_RES | UBC_CRR_PCB | UBC_CRR_BIE);
 289         ctrl_outl(val, UBC_CRR0);
 290
 291         /* Read UBC register that we wrote last, for checking update */
 292         val = ctrl_inl(UBC_CRR0);
 293
 294 #else   /* CONFIG_CPU_SH4A */
 295         ctrl_outl(pc, UBC_BARA);
 296
 297 #ifdef CONFIG_MMU
 298         /* We don't have any ASID settings for the SH-2! */
 299         if (current_cpu_data.type != CPU_SH7604)
 300                 ctrl_outb(asid, UBC_BASRA);
 301 #endif
 302
 303         ctrl_outl(0, UBC_BAMRA);
 304
 305         if (current_cpu_data.type == CPU_SH7729 ||
 306             current_cpu_data.type == CPU_SH7710 ||
 307             current_cpu_data.type == CPU_SH7712) {
 308                 ctrl_outw(BBR_INST | BBR_READ | BBR_CPU, UBC_BBRA);
 309                 ctrl_outl(BRCR_PCBA | BRCR_PCTE, UBC_BRCR);
 310         } else {
 311                 ctrl_outw(BBR_INST | BBR_READ, UBC_BBRA);
 312                 ctrl_outw(BRCR_PCBA, UBC_BRCR);
 313         }
 314 #endif  /* CONFIG_CPU_SH4A */
 315 }
 316
 317 /*
 318  *      switch_to(x,y) should switch tasks from x to y.
 319  *
 320  */
 321 struct task_struct *__switch_to(struct task_struct *prev,
 322                                 struct task_struct *next)
 323 {
 324 #if defined(CONFIG_SH_FPU)
 325         unlazy_fpu(prev, task_pt_regs(prev));
 326 #endif
 327
 328 #ifdef CONFIG_PREEMPT
 329         {
 330                 unsigned long flags;
 331                 struct pt_regs *regs;
 332
 333                 local_irq_save(flags);
 334                 regs = task_pt_regs(prev);
 335                 if (user_mode(regs) && regs->regs[15] >= 0xc0000000) {
 336                         int offset = (int)regs->regs[15];
 337
 338                         /* Reset stack pointer: clear critical region mark */
 339                         regs->regs[15] = regs->regs[1];
 340                         if (regs->pc < regs->regs[0])
 341                                 /* Go to rewind point */
 342                                 regs->pc = regs->regs[0] + offset;
 343                 }
 344                 local_irq_restore(flags);
 345         }
 346 #endif
 347
 348 #ifdef CONFIG_MMU
 349         /*
 350          * Restore the kernel mode register
 351          *      k7 (r7_bank1)
 352          */
 353         asm volatile("ldc       %0, r7_bank"
 354                      : /* no output */
 355                      : "r" (task_thread_info(next)));
 356 #endif
 357
 358         /* If no tasks are using the UBC, we're done */
 359         if (ubc_usercnt == 0)
 360                 /* If no tasks are using the UBC, we're done */;
 361         else if (next->thread.ubc_pc && next->mm) {
 362                 int asid = 0;
 363 #ifdef CONFIG_MMU
 364                 asid |= cpu_asid(smp_processor_id(), next->mm);
 365 #endif
 366                 ubc_set_tracing(asid, next->thread.ubc_pc);
 367         } else {
 368 #if defined(CONFIG_CPU_SH4A)
 369                 ctrl_outl(UBC_CBR_INIT, UBC_CBR0);
 370                 ctrl_outl(UBC_CRR_INIT, UBC_CRR0);
 371 #else
 372                 ctrl_outw(0, UBC_BBRA);
 373                 ctrl_outw(0, UBC_BBRB);
 374 #endif
 375         }
 376
 377         return prev;
 378 }
 379
 380 asmlinkage int sys_fork(unsigned long r4, unsigned long r5,
 381                         unsigned long r6, unsigned long r7,
 382                         struct pt_regs __regs)
 383 {
 384         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 385 #ifdef CONFIG_MMU
 386         return do_fork(SIGCHLD, regs->regs[15], regs, 0, NULL, NULL);
 387 #else
 388         /* fork almost works, enough to trick you into looking elsewhere :-( */
 389         return -EINVAL;
 390 #endif
 391 }
 392
 393 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
 394                          unsigned long parent_tidptr,
 395                          unsigned long child_tidptr,
 396                          struct pt_regs __regs)
 397 {
 398         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 399         if (!newsp)
 400                 newsp = regs->regs[15];
 401         return do_fork(clone_flags, newsp, regs, 0,
 402                         (int __user *)parent_tidptr,
 403                         (int __user *)child_tidptr);
 404 }
 405
 406 /*
 407  * This is trivial, and on the face of it looks like it
 408  * could equally well be done in user mode.
 409  *
 410  * Not so, for quite unobvious reasons - register pressure.
 411  * In user mode vfork() cannot have a stack frame, and if
 412  * done by calling the "clone()" system call directly, you
 413  * do not have enough call-clobbered registers to hold all
 414  * the information you need.
 415  */
 416 asmlinkage int sys_vfork(unsigned long r4, unsigned long r5,
 417                          unsigned long r6, unsigned long r7,
 418                          struct pt_regs __regs)
 419 {
 420         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 421         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->regs[15], regs,
 422                        0, NULL, NULL);
 423 }
 424
 425 /*
 426  * sys_execve() executes a new program.
 427  */
 428 asmlinkage int sys_execve(char *ufilename, char **uargv,
 429                           char **uenvp, unsigned long r7,
 430                           struct pt_regs __regs)
 431 {
 432         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 433         int error;
 434         char *filename;
 435
 436         filename = getname((char __user *)ufilename);
 437         error = PTR_ERR(filename);
 438         if (IS_ERR(filename))
 439                 goto out;
 440
 441         error = do_execve(filename,
 442                           (char __user * __user *)uargv,
 443                           (char __user * __user *)uenvp,
 444                           regs);
 445         if (error == 0) {
 446                 task_lock(current);
 447                 current->ptrace &= ~PT_DTRACE;
 448                 task_unlock(current);
 449         }
 450         putname(filename);
 451 out:
 452         return error;
 453 }
 454
 455 unsigned long get_wchan(struct task_struct *p)
 456 {
 457         unsigned long schedule_frame;
 458         unsigned long pc;
 459
 460         if (!p || p == current || p->state == TASK_RUNNING)
 461                 return 0;
 462
 463         /*
 464          * The same comment as on the Alpha applies here, too ...
 465          */
 466         pc = thread_saved_pc(p);
 467         if (in_sched_functions(pc)) {
 468                 schedule_frame = (unsigned long)p->thread.sp;
 469                 return ((unsigned long *)schedule_frame)[21];
 470         }
 471
 472         return pc;
 473 }
 474
 475 asmlinkage void break_point_trap(void)
 476 {
 477         /* Clear tracing.  */
 478 #if defined(CONFIG_CPU_SH4A)
 479         ctrl_outl(UBC_CBR_INIT, UBC_CBR0);
 480         ctrl_outl(UBC_CRR_INIT, UBC_CRR0);
 481 #else
 482         ctrl_outw(0, UBC_BBRA);
 483         ctrl_outw(0, UBC_BBRB);
 484 #endif
 485         current->thread.ubc_pc = 0;
 486         ubc_usercnt -= 1;
 487
 488         force_sig(SIGTRAP, current);
 489 }
 490
 491 /*
 492  * Generic trap handler.
 493  */
 494 asmlinkage void debug_trap_handler(unsigned long r4, unsigned long r5,
 495                                    unsigned long r6, unsigned long r7,
 496                                    struct pt_regs __regs)
 497 {
 498         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 499
 500         /* Rewind */
 501         regs->pc -= instruction_size(ctrl_inw(regs->pc - 4));
 502
 503         if (notify_die(DIE_TRAP, "debug trap", regs, 0, regs->tra & 0xff,
 504                        SIGTRAP) == NOTIFY_STOP)
 505                 return;
 506
 507         force_sig(SIGTRAP, current);
 508 }
 509
 510 /*
 511  * Special handler for BUG() traps.
 512  */
 513 asmlinkage void bug_trap_handler(unsigned long r4, unsigned long r5,
 514                                  unsigned long r6, unsigned long r7,
 515                                  struct pt_regs __regs)
 516 {
 517         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 518
 519         /* Rewind */
 520         regs->pc -= instruction_size(ctrl_inw(regs->pc - 4));
 521
 522         if (notify_die(DIE_TRAP, "bug trap", regs, 0, TRAPA_BUG_OPCODE & 0xff,
 523                        SIGTRAP) == NOTIFY_STOP)
 524                 return;
 525
 526 #ifdef CONFIG_BUG
 527         if (__kernel_text_address(instruction_pointer(regs))) {
 528                 u16 insn = *(u16 *)instruction_pointer(regs);
 529                 if (insn == TRAPA_BUG_OPCODE)
 530                         handle_BUG(regs);
 531         }
 532 #endif
 533
 534         force_sig(SIGTRAP, current);
 535 }