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