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