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