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