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 - 2006  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/uaccess.h>
  19 #include <asm/mmu_context.h>
  20 #include <asm/ubc.h>
  21
  22 static int hlt_counter;
  23 int ubc_usercnt = 0;
  24
  25 #define HARD_IDLE_TIMEOUT (HZ / 3)
  26
  27 void (*pm_idle)(void);
  28 void (*pm_power_off)(void);
  29 EXPORT_SYMBOL(pm_power_off);
  30
  31 void disable_hlt(void)
  32 {
  33         hlt_counter++;
  34 }
  35 EXPORT_SYMBOL(disable_hlt);
  36
  37 void enable_hlt(void)
  38 {
  39         hlt_counter--;
  40 }
  41 EXPORT_SYMBOL(enable_hlt);
  42
  43 void default_idle(void)
  44 {
  45         if (!hlt_counter)
  46                 cpu_sleep();
  47         else
  48                 cpu_relax();
  49 }
  50
  51 void cpu_idle(void)
  52 {
  53         /* endless idle loop with no priority at all */
  54         while (1) {
  55                 void (*idle)(void) = pm_idle;
  56
  57                 if (!idle)
  58                         idle = default_idle;
  59
  60                 while (!need_resched())
  61                         idle();
  62
  63                 preempt_enable_no_resched();
  64                 schedule();
  65                 preempt_disable();
  66         }
  67 }
  68
  69 void machine_restart(char * __unused)
  70 {
  71         /* SR.BL=1 and invoke address error to let CPU reset (manual reset) */
  72         asm volatile("ldc %0, sr\n\t"
  73                      "mov.l @%1, %0" : : "r" (0x10000000), "r" (0x80000001));
  74 }
  75
  76 void machine_halt(void)
  77 {
  78         local_irq_disable();
  79
  80         while (1)
  81                 cpu_sleep();
  82 }
  83
  84 void machine_power_off(void)
  85 {
  86         if (pm_power_off)
  87                 pm_power_off();
  88 }
  89
  90 void show_regs(struct pt_regs * regs)
  91 {
  92         printk("\n");
  93         printk("Pid : %d, Comm: %20s\n", current->pid, current->comm);
  94         print_symbol("PC is at %s\n", instruction_pointer(regs));
  95         printk("PC  : %08lx SP  : %08lx SR  : %08lx ",
  96                regs->pc, regs->regs[15], regs->sr);
  97 #ifdef CONFIG_MMU
  98         printk("TEA : %08x    ", ctrl_inl(MMU_TEA));
  99 #else
 100         printk("                  ");
 101 #endif
 102         printk("%s\n", print_tainted());
 103
 104         printk("R0  : %08lx R1  : %08lx R2  : %08lx R3  : %08lx\n",
 105                regs->regs[0],regs->regs[1],
 106                regs->regs[2],regs->regs[3]);
 107         printk("R4  : %08lx R5  : %08lx R6  : %08lx R7  : %08lx\n",
 108                regs->regs[4],regs->regs[5],
 109                regs->regs[6],regs->regs[7]);
 110         printk("R8  : %08lx R9  : %08lx R10 : %08lx R11 : %08lx\n",
 111                regs->regs[8],regs->regs[9],
 112                regs->regs[10],regs->regs[11]);
 113         printk("R12 : %08lx R13 : %08lx R14 : %08lx\n",
 114                regs->regs[12],regs->regs[13],
 115                regs->regs[14]);
 116         printk("MACH: %08lx MACL: %08lx GBR : %08lx PR  : %08lx\n",
 117                regs->mach, regs->macl, regs->gbr, regs->pr);
 118
 119         show_trace(NULL, (unsigned long *)regs->regs[15], regs);
 120 }
 121
 122 /*
 123  * Create a kernel thread
 124  */
 125
 126 /*
 127  * This is the mechanism for creating a new kernel thread.
 128  *
 129  */
 130 extern void kernel_thread_helper(void);
 131 __asm__(".align 5\n"
 132         "kernel_thread_helper:\n\t"
 133         "jsr    @r5\n\t"
 134         " nop\n\t"
 135         "mov.l  1f, r1\n\t"
 136         "jsr    @r1\n\t"
 137         " mov   r0, r4\n\t"
 138         ".align 2\n\t"
 139         "1:.long do_exit");
 140
 141 /* Don't use this in BL=1(cli).  Or else, CPU resets! */
 142 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 143 {
 144         struct pt_regs regs;
 145
 146         memset(&regs, 0, sizeof(regs));
 147         regs.regs[4] = (unsigned long)arg;
 148         regs.regs[5] = (unsigned long)fn;
 149
 150         regs.pc = (unsigned long)kernel_thread_helper;
 151         regs.sr = (1 << 30);
 152
 153         /* Ok, create the new process.. */
 154         return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
 155                        &regs, 0, NULL, NULL);
 156 }
 157
 158 /*
 159  * Free current thread data structures etc..
 160  */
 161 void exit_thread(void)
 162 {
 163         if (current->thread.ubc_pc) {
 164                 current->thread.ubc_pc = 0;
 165                 ubc_usercnt -= 1;
 166         }
 167 }
 168
 169 void flush_thread(void)
 170 {
 171 #if defined(CONFIG_SH_FPU)
 172         struct task_struct *tsk = current;
 173         /* Forget lazy FPU state */
 174         clear_fpu(tsk, task_pt_regs(tsk));
 175         clear_used_math();
 176 #endif
 177 }
 178
 179 void release_thread(struct task_struct *dead_task)
 180 {
 181         /* do nothing */
 182 }
 183
 184 /* Fill in the fpu structure for a core dump.. */
 185 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 186 {
 187         int fpvalid = 0;
 188
 189 #if defined(CONFIG_SH_FPU)
 190         struct task_struct *tsk = current;
 191
 192         fpvalid = !!tsk_used_math(tsk);
 193         if (fpvalid) {
 194                 unlazy_fpu(tsk, regs);
 195                 memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu));
 196         }
 197 #endif
 198
 199         return fpvalid;
 200 }
 201
 202 /*
 203  * Capture the user space registers if the task is not running (in user space)
 204  */
 205 int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
 206 {
 207         struct pt_regs ptregs;
 208
 209         ptregs = *task_pt_regs(tsk);
 210         elf_core_copy_regs(regs, &ptregs);
 211
 212         return 1;
 213 }
 214
 215 int dump_task_fpu(struct task_struct *tsk, elf_fpregset_t *fpu)
 216 {
 217         int fpvalid = 0;
 218
 219 #if defined(CONFIG_SH_FPU)
 220         fpvalid = !!tsk_used_math(tsk);
 221         if (fpvalid) {
 222                 unlazy_fpu(tsk, task_pt_regs(tsk));
 223                 memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu));
 224         }
 225 #endif
 226
 227         return fpvalid;
 228 }
 229
 230 asmlinkage void ret_from_fork(void);
 231
 232 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 233                 unsigned long unused,
 234                 struct task_struct *p, struct pt_regs *regs)
 235 {
 236         struct thread_info *ti = task_thread_info(p);
 237         struct pt_regs *childregs;
 238 #if defined(CONFIG_SH_FPU)
 239         struct task_struct *tsk = current;
 240
 241         unlazy_fpu(tsk, regs);
 242         p->thread.fpu = tsk->thread.fpu;
 243         copy_to_stopped_child_used_math(p);
 244 #endif
 245
 246         childregs = task_pt_regs(p);
 247         *childregs = *regs;
 248
 249         if (user_mode(regs)) {
 250                 childregs->regs[15] = usp;
 251                 ti->addr_limit = USER_DS;
 252         } else {
 253                 childregs->regs[15] = (unsigned long)task_stack_page(p) +
 254                                                         THREAD_SIZE;
 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                 ctrl_outw(BBR_INST | BBR_READ | BBR_CPU, UBC_BBRA);
 305                 ctrl_outl(BRCR_PCBA | BRCR_PCTE, UBC_BRCR);
 306         } else {
 307                 ctrl_outw(BBR_INST | BBR_READ, UBC_BBRA);
 308                 ctrl_outw(BRCR_PCBA, UBC_BRCR);
 309         }
 310 #endif  /* CONFIG_CPU_SH4A */
 311 }
 312
 313 /*
 314  *      switch_to(x,y) should switch tasks from x to y.
 315  *
 316  */
 317 struct task_struct *__switch_to(struct task_struct *prev,
 318                                 struct task_struct *next)
 319 {
 320 #if defined(CONFIG_SH_FPU)
 321         unlazy_fpu(prev, task_pt_regs(prev));
 322 #endif
 323
 324 #ifdef CONFIG_PREEMPT
 325         {
 326                 unsigned long flags;
 327                 struct pt_regs *regs;
 328
 329                 local_irq_save(flags);
 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                 local_irq_restore(flags);
 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         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 381 #ifdef CONFIG_MMU
 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 *ufilename, char **uargv,
 425                           char **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((char __user *)ufilename);
 433         error = PTR_ERR(filename);
 434         if (IS_ERR(filename))
 435                 goto out;
 436
 437         error = do_execve(filename,
 438                           (char __user * __user *)uargv,
 439                           (char __user * __user *)uenvp,
 440                           regs);
 441         if (error == 0) {
 442                 task_lock(current);
 443                 current->ptrace &= ~PT_DTRACE;
 444                 task_unlock(current);
 445         }
 446         putname(filename);
 447 out:
 448         return error;
 449 }
 450
 451 unsigned long get_wchan(struct task_struct *p)
 452 {
 453         unsigned long schedule_frame;
 454         unsigned long pc;
 455
 456         if (!p || p == current || p->state == TASK_RUNNING)
 457                 return 0;
 458
 459         /*
 460          * The same comment as on the Alpha applies here, too ...
 461          */
 462         pc = thread_saved_pc(p);
 463         if (in_sched_functions(pc)) {
 464                 schedule_frame = (unsigned long)p->thread.sp;
 465                 return ((unsigned long *)schedule_frame)[21];
 466         }
 467
 468         return pc;
 469 }
 470
 471 asmlinkage void break_point_trap(void)
 472 {
 473         /* Clear tracing.  */
 474 #if defined(CONFIG_CPU_SH4A)
 475         ctrl_outl(UBC_CBR_INIT, UBC_CBR0);
 476         ctrl_outl(UBC_CRR_INIT, UBC_CRR0);
 477 #else
 478         ctrl_outw(0, UBC_BBRA);
 479         ctrl_outw(0, UBC_BBRB);
 480 #endif
 481         current->thread.ubc_pc = 0;
 482         ubc_usercnt -= 1;
 483
 484         force_sig(SIGTRAP, current);
 485 }
 486
 487 /*
 488  * Generic trap handler.
 489  */
 490 asmlinkage void debug_trap_handler(unsigned long r4, unsigned long r5,
 491                                    unsigned long r6, unsigned long r7,
 492                                    struct pt_regs __regs)
 493 {
 494         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 495
 496         /* Rewind */
 497         regs->pc -= 2;
 498
 499         force_sig(SIGTRAP, current);
 500 }
 501
 502 /*
 503  * Special handler for BUG() traps.
 504  */
 505 asmlinkage void bug_trap_handler(unsigned long r4, unsigned long r5,
 506                                  unsigned long r6, unsigned long r7,
 507                                  struct pt_regs __regs)
 508 {
 509         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 510
 511         /* Rewind */
 512         regs->pc -= 2;
 513
 514 #ifdef CONFIG_BUG
 515         if (__kernel_text_address(instruction_pointer(regs))) {
 516                 u16 insn = *(u16 *)instruction_pointer(regs);
 517                 if (insn == TRAPA_BUG_OPCODE)
 518                         handle_BUG(regs);
 519         }
 520 #endif
 521
 522         force_sig(SIGTRAP, current);
 523 }