release/src-rt-6.x/linux/linux-2.6/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 <linux/tick.h>
  20 #include <asm/uaccess.h>
  21 #include <asm/mmu_context.h>
  22 #include <asm/pgalloc.h>
  23 #include <asm/system.h>
  24 #include <asm/ubc.h>
  25
  26 static int hlt_counter;
  27 int ubc_usercnt = 0;
  28
  29 void (*pm_idle)(void);
  30 void (*pm_power_off)(void);
  31 EXPORT_SYMBOL(pm_power_off);
  32
  33 void disable_hlt(void)
  34 {
  35         hlt_counter++;
  36 }
  37 EXPORT_SYMBOL(disable_hlt);
  38
  39 void enable_hlt(void)
  40 {
  41         hlt_counter--;
  42 }
  43 EXPORT_SYMBOL(enable_hlt);
  44
  45 static int __init nohlt_setup(char *__unused)
  46 {
  47         hlt_counter = 1;
  48         return 1;
  49 }
  50 __setup("nohlt", nohlt_setup);
  51
  52 static int __init hlt_setup(char *__unused)
  53 {
  54         hlt_counter = 0;
  55         return 1;
  56 }
  57 __setup("hlt", hlt_setup);
  58
  59 void default_idle(void)
  60 {
  61         if (!hlt_counter) {
  62                 clear_thread_flag(TIF_POLLING_NRFLAG);
  63                 smp_mb__after_clear_bit();
  64                 set_bl_bit();
  65                 while (!need_resched())
  66                         cpu_sleep();
  67                 clear_bl_bit();
  68                 set_thread_flag(TIF_POLLING_NRFLAG);
  69         } else
  70                 while (!need_resched())
  71                         cpu_relax();
  72 }
  73
  74 void cpu_idle(void)
  75 {
  76         set_thread_flag(TIF_POLLING_NRFLAG);
  77
  78         /* endless idle loop with no priority at all */
  79         while (1) {
  80                 void (*idle)(void) = pm_idle;
  81
  82                 if (!idle)
  83                         idle = default_idle;
  84
  85                 tick_nohz_stop_sched_tick();
  86                 while (!need_resched())
  87                         idle();
  88                 tick_nohz_restart_sched_tick();
  89
  90                 preempt_enable_no_resched();
  91                 schedule();
  92                 preempt_disable();
  93                 check_pgt_cache();
  94         }
  95 }
  96
  97 void machine_restart(char * __unused)
  98 {
  99         /* SR.BL=1 and invoke address error to let CPU reset (manual reset) */
 100         asm volatile("ldc %0, sr\n\t"
 101                      "mov.l @%1, %0" : : "r" (0x10000000), "r" (0x80000001));
 102 }
 103
 104 void machine_halt(void)
 105 {
 106         local_irq_disable();
 107
 108         while (1)
 109                 cpu_sleep();
 110 }
 111
 112 void machine_power_off(void)
 113 {
 114         if (pm_power_off)
 115                 pm_power_off();
 116 }
 117
 118 void show_regs(struct pt_regs * regs)
 119 {
 120         printk("\n");
 121         printk("Pid : %d, Comm: %20s\n", current->pid, current->comm);
 122         print_symbol("PC is at %s\n", instruction_pointer(regs));
 123         printk("PC  : %08lx SP  : %08lx SR  : %08lx ",
 124                regs->pc, regs->regs[15], regs->sr);
 125 #ifdef CONFIG_MMU
 126         printk("TEA : %08x    ", ctrl_inl(MMU_TEA));
 127 #else
 128         printk("                  ");
 129 #endif
 130         printk("%s\n", print_tainted());
 131
 132         printk("R0  : %08lx R1  : %08lx R2  : %08lx R3  : %08lx\n",
 133                regs->regs[0],regs->regs[1],
 134                regs->regs[2],regs->regs[3]);
 135         printk("R4  : %08lx R5  : %08lx R6  : %08lx R7  : %08lx\n",
 136                regs->regs[4],regs->regs[5],
 137                regs->regs[6],regs->regs[7]);
 138         printk("R8  : %08lx R9  : %08lx R10 : %08lx R11 : %08lx\n",
 139                regs->regs[8],regs->regs[9],
 140                regs->regs[10],regs->regs[11]);
 141         printk("R12 : %08lx R13 : %08lx R14 : %08lx\n",
 142                regs->regs[12],regs->regs[13],
 143                regs->regs[14]);
 144         printk("MACH: %08lx MACL: %08lx GBR : %08lx PR  : %08lx\n",
 145                regs->mach, regs->macl, regs->gbr, regs->pr);
 146
 147         show_trace(NULL, (unsigned long *)regs->regs[15], regs);
 148 }
 149
 150 /*
 151  * Create a kernel thread
 152  */
 153
 154 /*
 155  * This is the mechanism for creating a new kernel thread.
 156  *
 157  */
 158 extern void kernel_thread_helper(void);
 159 __asm__(".align 5\n"
 160         "kernel_thread_helper:\n\t"
 161         "jsr    @r5\n\t"
 162         " nop\n\t"
 163         "mov.l  1f, r1\n\t"
 164         "jsr    @r1\n\t"
 165         " mov   r0, r4\n\t"
 166         ".align 2\n\t"
 167         "1:.long do_exit");
 168
 169 /* Don't use this in BL=1(cli).  Or else, CPU resets! */
 170 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 171 {
 172         struct pt_regs regs;
 173
 174         memset(&regs, 0, sizeof(regs));
 175         regs.regs[4] = (unsigned long)arg;
 176         regs.regs[5] = (unsigned long)fn;
 177
 178         regs.pc = (unsigned long)kernel_thread_helper;
 179         regs.sr = (1 << 30);
 180
 181         /* Ok, create the new process.. */
 182         return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
 183                        &regs, 0, NULL, NULL);
 184 }
 185
 186 /*
 187  * Free current thread data structures etc..
 188  */
 189 void exit_thread(void)
 190 {
 191         if (current->thread.ubc_pc) {
 192                 current->thread.ubc_pc = 0;
 193                 ubc_usercnt -= 1;
 194         }
 195 }
 196
 197 void flush_thread(void)
 198 {
 199 #if defined(CONFIG_SH_FPU)
 200         struct task_struct *tsk = current;
 201         /* Forget lazy FPU state */
 202         clear_fpu(tsk, task_pt_regs(tsk));
 203         clear_used_math();
 204 #endif
 205 }
 206
 207 void release_thread(struct task_struct *dead_task)
 208 {
 209         /* do nothing */
 210 }
 211
 212 /* Fill in the fpu structure for a core dump.. */
 213 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 214 {
 215         int fpvalid = 0;
 216
 217 #if defined(CONFIG_SH_FPU)
 218         struct task_struct *tsk = current;
 219
 220         fpvalid = !!tsk_used_math(tsk);
 221         if (fpvalid) {
 222                 unlazy_fpu(tsk, regs);
 223                 memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu));
 224         }
 225 #endif
 226
 227         return fpvalid;
 228 }
 229
 230 /*
 231  * Capture the user space registers if the task is not running (in user space)
 232  */
 233 int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
 234 {
 235         struct pt_regs ptregs;
 236
 237         ptregs = *task_pt_regs(tsk);
 238         elf_core_copy_regs(regs, &ptregs);
 239
 240         return 1;
 241 }
 242
 243 int dump_task_fpu(struct task_struct *tsk, elf_fpregset_t *fpu)
 244 {
 245         int fpvalid = 0;
 246
 247 #if defined(CONFIG_SH_FPU)
 248         fpvalid = !!tsk_used_math(tsk);
 249         if (fpvalid) {
 250                 unlazy_fpu(tsk, task_pt_regs(tsk));
 251                 memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu));
 252         }
 253 #endif
 254
 255         return fpvalid;
 256 }
 257
 258 asmlinkage void ret_from_fork(void);
 259
 260 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 261                 unsigned long unused,
 262                 struct task_struct *p, struct pt_regs *regs)
 263 {
 264         struct thread_info *ti = task_thread_info(p);
 265         struct pt_regs *childregs;
 266 #if defined(CONFIG_SH_FPU)
 267         struct task_struct *tsk = current;
 268
 269         unlazy_fpu(tsk, regs);
 270         p->thread.fpu = tsk->thread.fpu;
 271         copy_to_stopped_child_used_math(p);
 272 #endif
 273
 274         childregs = task_pt_regs(p);
 275         *childregs = *regs;
 276
 277         if (user_mode(regs)) {
 278                 childregs->regs[15] = usp;
 279                 ti->addr_limit = USER_DS;
 280         } else {
 281                 childregs->regs[15] = (unsigned long)childregs;
 282                 ti->addr_limit = KERNEL_DS;
 283         }
 284
 285         if (clone_flags & CLONE_SETTLS)
 286                 childregs->gbr = childregs->regs[0];
 287
 288         childregs->regs[0] = 0; /* Set return value for child */
 289
 290         p->thread.sp = (unsigned long) childregs;
 291         p->thread.pc = (unsigned long) ret_from_fork;
 292
 293         p->thread.ubc_pc = 0;
 294
 295         return 0;
 296 }
 297
 298 /* Tracing by user break controller.  */
 299 static void ubc_set_tracing(int asid, unsigned long pc)
 300 {
 301 #if defined(CONFIG_CPU_SH4A)
 302         unsigned long val;
 303
 304         val = (UBC_CBR_ID_INST | UBC_CBR_RW_READ | UBC_CBR_CE);
 305         val |= (UBC_CBR_AIE | UBC_CBR_AIV_SET(asid));
 306
 307         ctrl_outl(val, UBC_CBR0);
 308         ctrl_outl(pc,  UBC_CAR0);
 309         ctrl_outl(0x0, UBC_CAMR0);
 310         ctrl_outl(0x0, UBC_CBCR);
 311
 312         val = (UBC_CRR_RES | UBC_CRR_PCB | UBC_CRR_BIE);
 313         ctrl_outl(val, UBC_CRR0);
 314
 315         /* Read UBC register that we wrote last, for checking update */
 316         val = ctrl_inl(UBC_CRR0);
 317
 318 #else   /* CONFIG_CPU_SH4A */
 319         ctrl_outl(pc, UBC_BARA);
 320
 321 #ifdef CONFIG_MMU
 322         /* We don't have any ASID settings for the SH-2! */
 323         if (current_cpu_data.type != CPU_SH7604)
 324                 ctrl_outb(asid, UBC_BASRA);
 325 #endif
 326
 327         ctrl_outl(0, UBC_BAMRA);
 328
 329         if (current_cpu_data.type == CPU_SH7729 ||
 330             current_cpu_data.type == CPU_SH7710 ||
 331             current_cpu_data.type == CPU_SH7712) {
 332                 ctrl_outw(BBR_INST | BBR_READ | BBR_CPU, UBC_BBRA);
 333                 ctrl_outl(BRCR_PCBA | BRCR_PCTE, UBC_BRCR);
 334         } else {
 335                 ctrl_outw(BBR_INST | BBR_READ, UBC_BBRA);
 336                 ctrl_outw(BRCR_PCBA, UBC_BRCR);
 337         }
 338 #endif  /* CONFIG_CPU_SH4A */
 339 }
 340
 341 /*
 342  *      switch_to(x,y) should switch tasks from x to y.
 343  *
 344  */
 345 struct task_struct *__switch_to(struct task_struct *prev,
 346                                 struct task_struct *next)
 347 {
 348 #if defined(CONFIG_SH_FPU)
 349         unlazy_fpu(prev, task_pt_regs(prev));
 350 #endif
 351
 352 #ifdef CONFIG_PREEMPT
 353         {
 354                 unsigned long flags;
 355                 struct pt_regs *regs;
 356
 357                 local_irq_save(flags);
 358                 regs = task_pt_regs(prev);
 359                 if (user_mode(regs) && regs->regs[15] >= 0xc0000000) {
 360                         int offset = (int)regs->regs[15];
 361
 362                         /* Reset stack pointer: clear critical region mark */
 363                         regs->regs[15] = regs->regs[1];
 364                         if (regs->pc < regs->regs[0])
 365                                 /* Go to rewind point */
 366                                 regs->pc = regs->regs[0] + offset;
 367                 }
 368                 local_irq_restore(flags);
 369         }
 370 #endif
 371
 372 #ifdef CONFIG_MMU
 373         /*
 374          * Restore the kernel mode register
 375          *      k7 (r7_bank1)
 376          */
 377         asm volatile("ldc       %0, r7_bank"
 378                      : /* no output */
 379                      : "r" (task_thread_info(next)));
 380 #endif
 381
 382         /* If no tasks are using the UBC, we're done */
 383         if (ubc_usercnt == 0)
 384                 /* If no tasks are using the UBC, we're done */;
 385         else if (next->thread.ubc_pc && next->mm) {
 386                 int asid = 0;
 387 #ifdef CONFIG_MMU
 388                 asid |= cpu_asid(smp_processor_id(), next->mm);
 389 #endif
 390                 ubc_set_tracing(asid, next->thread.ubc_pc);
 391         } else {
 392 #if defined(CONFIG_CPU_SH4A)
 393                 ctrl_outl(UBC_CBR_INIT, UBC_CBR0);
 394                 ctrl_outl(UBC_CRR_INIT, UBC_CRR0);
 395 #else
 396                 ctrl_outw(0, UBC_BBRA);
 397                 ctrl_outw(0, UBC_BBRB);
 398 #endif
 399         }
 400
 401         return prev;
 402 }
 403
 404 asmlinkage int sys_fork(unsigned long r4, unsigned long r5,
 405                         unsigned long r6, unsigned long r7,
 406                         struct pt_regs __regs)
 407 {
 408         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 409 #ifdef CONFIG_MMU
 410         return do_fork(SIGCHLD, regs->regs[15], regs, 0, NULL, NULL);
 411 #else
 412         /* fork almost works, enough to trick you into looking elsewhere :-( */
 413         return -EINVAL;
 414 #endif
 415 }
 416
 417 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
 418                          unsigned long parent_tidptr,
 419                          unsigned long child_tidptr,
 420                          struct pt_regs __regs)
 421 {
 422         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 423         if (!newsp)
 424                 newsp = regs->regs[15];
 425         return do_fork(clone_flags, newsp, regs, 0,
 426                         (int __user *)parent_tidptr,
 427                         (int __user *)child_tidptr);
 428 }
 429
 430 /*
 431  * This is trivial, and on the face of it looks like it
 432  * could equally well be done in user mode.
 433  *
 434  * Not so, for quite unobvious reasons - register pressure.
 435  * In user mode vfork() cannot have a stack frame, and if
 436  * done by calling the "clone()" system call directly, you
 437  * do not have enough call-clobbered registers to hold all
 438  * the information you need.
 439  */
 440 asmlinkage int sys_vfork(unsigned long r4, unsigned long r5,
 441                          unsigned long r6, unsigned long r7,
 442                          struct pt_regs __regs)
 443 {
 444         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 445         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->regs[15], regs,
 446                        0, NULL, NULL);
 447 }
 448
 449 /*
 450  * sys_execve() executes a new program.
 451  */
 452 asmlinkage int sys_execve(char *ufilename, char **uargv,
 453                           char **uenvp, unsigned long r7,
 454                           struct pt_regs __regs)
 455 {
 456         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 457         int error;
 458         char *filename;
 459
 460         filename = getname((char __user *)ufilename);
 461         error = PTR_ERR(filename);
 462         if (IS_ERR(filename))
 463                 goto out;
 464
 465         error = do_execve(filename,
 466                           (char __user * __user *)uargv,
 467                           (char __user * __user *)uenvp,
 468                           regs);
 469         if (error == 0) {
 470                 task_lock(current);
 471                 current->ptrace &= ~PT_DTRACE;
 472                 task_unlock(current);
 473         }
 474         putname(filename);
 475 out:
 476         return error;
 477 }
 478
 479 unsigned long get_wchan(struct task_struct *p)
 480 {
 481         unsigned long schedule_frame;
 482         unsigned long pc;
 483
 484         if (!p || p == current || p->state == TASK_RUNNING)
 485                 return 0;
 486
 487         /*
 488          * The same comment as on the Alpha applies here, too ...
 489          */
 490         pc = thread_saved_pc(p);
 491         if (in_sched_functions(pc)) {
 492                 schedule_frame = (unsigned long)p->thread.sp;
 493                 return ((unsigned long *)schedule_frame)[21];
 494         }
 495
 496         return pc;
 497 }
 498
 499 asmlinkage void break_point_trap(void)
 500 {
 501         /* Clear tracing.  */
 502 #if defined(CONFIG_CPU_SH4A)
 503         ctrl_outl(UBC_CBR_INIT, UBC_CBR0);
 504         ctrl_outl(UBC_CRR_INIT, UBC_CRR0);
 505 #else
 506         ctrl_outw(0, UBC_BBRA);
 507         ctrl_outw(0, UBC_BBRB);
 508 #endif
 509         current->thread.ubc_pc = 0;
 510         ubc_usercnt -= 1;
 511
 512         force_sig(SIGTRAP, current);
 513 }
 514
 515 /*
 516  * Generic trap handler.
 517  */
 518 asmlinkage void debug_trap_handler(unsigned long r4, unsigned long r5,
 519                                    unsigned long r6, unsigned long r7,
 520                                    struct pt_regs __regs)
 521 {
 522         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 523
 524         /* Rewind */
 525         regs->pc -= instruction_size(ctrl_inw(regs->pc - 4));
 526
 527         if (notify_die(DIE_TRAP, "debug trap", regs, 0, regs->tra & 0xff,
 528                        SIGTRAP) == NOTIFY_STOP)
 529                 return;
 530
 531         force_sig(SIGTRAP, current);
 532 }
 533
 534 /*
 535  * Special handler for BUG() traps.
 536  */
 537 asmlinkage void bug_trap_handler(unsigned long r4, unsigned long r5,
 538                                  unsigned long r6, unsigned long r7,
 539                                  struct pt_regs __regs)
 540 {
 541         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 542
 543         /* Rewind */
 544         regs->pc -= instruction_size(ctrl_inw(regs->pc - 4));
 545
 546         if (notify_die(DIE_TRAP, "bug trap", regs, 0, TRAPA_BUG_OPCODE & 0xff,
 547                        SIGTRAP) == NOTIFY_STOP)
 548                 return;
 549
 550 #ifdef CONFIG_BUG
 551         if (__kernel_text_address(instruction_pointer(regs))) {
 552                 u16 insn = *(u16 *)instruction_pointer(regs);
 553                 if (insn == TRAPA_BUG_OPCODE)
 554                         handle_BUG(regs);
 555         }
 556 #endif
 557
 558         force_sig(SIGTRAP, current);
 559 }