arch/sh/kernel/process_32.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 <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 #include <asm/fpu.h>
  29
  30 static int hlt_counter;
  31 int ubc_usercnt = 0;
  32
  33 void (*pm_idle)(void);
  34 void (*pm_power_off)(void);
  35 EXPORT_SYMBOL(pm_power_off);
  36
  37 void disable_hlt(void)
  38 {
  39         hlt_counter++;
  40 }
  41 EXPORT_SYMBOL(disable_hlt);
  42
  43 void enable_hlt(void)
  44 {
  45         hlt_counter--;
  46 }
  47 EXPORT_SYMBOL(enable_hlt);
  48
  49 static int __init nohlt_setup(char *__unused)
  50 {
  51         hlt_counter = 1;
  52         return 1;
  53 }
  54 __setup("nohlt", nohlt_setup);
  55
  56 static int __init hlt_setup(char *__unused)
  57 {
  58         hlt_counter = 0;
  59         return 1;
  60 }
  61 __setup("hlt", hlt_setup);
  62
  63 void default_idle(void)
  64 {
  65         if (!hlt_counter) {
  66                 clear_thread_flag(TIF_POLLING_NRFLAG);
  67                 smp_mb__after_clear_bit();
  68                 set_bl_bit();
  69                 while (!need_resched())
  70                         cpu_sleep();
  71                 clear_bl_bit();
  72                 set_thread_flag(TIF_POLLING_NRFLAG);
  73         } else
  74                 while (!need_resched())
  75                         cpu_relax();
  76 }
  77
  78 void cpu_idle(void)
  79 {
  80         set_thread_flag(TIF_POLLING_NRFLAG);
  81
  82         /* endless idle loop with no priority at all */
  83         while (1) {
  84                 void (*idle)(void) = pm_idle;
  85
  86                 if (!idle)
  87                         idle = default_idle;
  88
  89                 tick_nohz_stop_sched_tick();
  90                 while (!need_resched())
  91                         idle();
  92                 tick_nohz_restart_sched_tick();
  93
  94                 preempt_enable_no_resched();
  95                 schedule();
  96                 preempt_disable();
  97                 check_pgt_cache();
  98         }
  99 }
 100
 101 void machine_restart(char * __unused)
 102 {
 103         /* SR.BL=1 and invoke address error to let CPU reset (manual reset) */
 104         asm volatile("ldc %0, sr\n\t"
 105                      "mov.l @%1, %0" : : "r" (0x10000000), "r" (0x80000001));
 106 }
 107
 108 void machine_halt(void)
 109 {
 110         local_irq_disable();
 111
 112         while (1)
 113                 cpu_sleep();
 114 }
 115
 116 void machine_power_off(void)
 117 {
 118         if (pm_power_off)
 119                 pm_power_off();
 120 }
 121
 122 void show_regs(struct pt_regs * regs)
 123 {
 124         printk("\n");
 125         printk("Pid : %d, Comm: %20s\n", task_pid_nr(current), current->comm);
 126         print_symbol("PC is at %s\n", instruction_pointer(regs));
 127         printk("PC  : %08lx SP  : %08lx SR  : %08lx ",
 128                regs->pc, regs->regs[15], regs->sr);
 129 #ifdef CONFIG_MMU
 130         printk("TEA : %08x    ", ctrl_inl(MMU_TEA));
 131 #else
 132         printk("                  ");
 133 #endif
 134         printk("%s\n", print_tainted());
 135
 136         printk("R0  : %08lx R1  : %08lx R2  : %08lx R3  : %08lx\n",
 137                regs->regs[0],regs->regs[1],
 138                regs->regs[2],regs->regs[3]);
 139         printk("R4  : %08lx R5  : %08lx R6  : %08lx R7  : %08lx\n",
 140                regs->regs[4],regs->regs[5],
 141                regs->regs[6],regs->regs[7]);
 142         printk("R8  : %08lx R9  : %08lx R10 : %08lx R11 : %08lx\n",
 143                regs->regs[8],regs->regs[9],
 144                regs->regs[10],regs->regs[11]);
 145         printk("R12 : %08lx R13 : %08lx R14 : %08lx\n",
 146                regs->regs[12],regs->regs[13],
 147                regs->regs[14]);
 148         printk("MACH: %08lx MACL: %08lx GBR : %08lx PR  : %08lx\n",
 149                regs->mach, regs->macl, regs->gbr, regs->pr);
 150
 151         show_trace(NULL, (unsigned long *)regs->regs[15], regs);
 152 }
 153
 154 /*
 155  * Create a kernel thread
 156  */
 157
 158 /*
 159  * This is the mechanism for creating a new kernel thread.
 160  *
 161  */
 162 extern void kernel_thread_helper(void);
 163 __asm__(".align 5\n"
 164         "kernel_thread_helper:\n\t"
 165         "jsr    @r5\n\t"
 166         " nop\n\t"
 167         "mov.l  1f, r1\n\t"
 168         "jsr    @r1\n\t"
 169         " mov   r0, r4\n\t"
 170         ".align 2\n\t"
 171         "1:.long do_exit");
 172
 173 /* Don't use this in BL=1(cli).  Or else, CPU resets! */
 174 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 175 {
 176         struct pt_regs regs;
 177
 178         memset(&regs, 0, sizeof(regs));
 179         regs.regs[4] = (unsigned long)arg;
 180         regs.regs[5] = (unsigned long)fn;
 181
 182         regs.pc = (unsigned long)kernel_thread_helper;
 183         regs.sr = (1 << 30);
 184
 185         /* Ok, create the new process.. */
 186         return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
 187                        &regs, 0, NULL, NULL);
 188 }
 189
 190 /*
 191  * Free current thread data structures etc..
 192  */
 193 void exit_thread(void)
 194 {
 195         if (current->thread.ubc_pc) {
 196                 current->thread.ubc_pc = 0;
 197                 ubc_usercnt -= 1;
 198         }
 199 }
 200
 201 void flush_thread(void)
 202 {
 203 #if defined(CONFIG_SH_FPU)
 204         struct task_struct *tsk = current;
 205         /* Forget lazy FPU state */
 206         clear_fpu(tsk, task_pt_regs(tsk));
 207         clear_used_math();
 208 #endif
 209 }
 210
 211 void release_thread(struct task_struct *dead_task)
 212 {
 213         /* do nothing */
 214 }
 215
 216 /* Fill in the fpu structure for a core dump.. */
 217 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 218 {
 219         int fpvalid = 0;
 220
 221 #if defined(CONFIG_SH_FPU)
 222         struct task_struct *tsk = current;
 223
 224         fpvalid = !!tsk_used_math(tsk);
 225         if (fpvalid) {
 226                 unlazy_fpu(tsk, regs);
 227                 memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu));
 228         }
 229 #endif
 230
 231         return fpvalid;
 232 }
 233
 234 asmlinkage void ret_from_fork(void);
 235
 236 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 237                 unsigned long unused,
 238                 struct task_struct *p, struct pt_regs *regs)
 239 {
 240         struct thread_info *ti = task_thread_info(p);
 241         struct pt_regs *childregs;
 242 #if defined(CONFIG_SH_FPU)
 243         struct task_struct *tsk = current;
 244
 245         unlazy_fpu(tsk, regs);
 246         p->thread.fpu = tsk->thread.fpu;
 247         copy_to_stopped_child_used_math(p);
 248 #endif
 249
 250         childregs = task_pt_regs(p);
 251         *childregs = *regs;
 252
 253         if (user_mode(regs)) {
 254                 childregs->regs[15] = usp;
 255                 ti->addr_limit = USER_DS;
 256         } else {
 257                 childregs->regs[15] = (unsigned long)childregs;
 258                 ti->addr_limit = KERNEL_DS;
 259         }
 260
 261         if (clone_flags & CLONE_SETTLS)
 262                 childregs->gbr = childregs->regs[0];
 263
 264         childregs->regs[0] = 0; /* Set return value for child */
 265
 266         p->thread.sp = (unsigned long) childregs;
 267         p->thread.pc = (unsigned long) ret_from_fork;
 268
 269         p->thread.ubc_pc = 0;
 270
 271         return 0;
 272 }
 273
 274 /* Tracing by user break controller.  */
 275 static void ubc_set_tracing(int asid, unsigned long pc)
 276 {
 277 #if defined(CONFIG_CPU_SH4A)
 278         unsigned long val;
 279
 280         val = (UBC_CBR_ID_INST | UBC_CBR_RW_READ | UBC_CBR_CE);
 281         val |= (UBC_CBR_AIE | UBC_CBR_AIV_SET(asid));
 282
 283         ctrl_outl(val, UBC_CBR0);
 284         ctrl_outl(pc,  UBC_CAR0);
 285         ctrl_outl(0x0, UBC_CAMR0);
 286         ctrl_outl(0x0, UBC_CBCR);
 287
 288         val = (UBC_CRR_RES | UBC_CRR_PCB | UBC_CRR_BIE);
 289         ctrl_outl(val, UBC_CRR0);
 290
 291         /* Read UBC register that we wrote last, for checking update */
 292         val = ctrl_inl(UBC_CRR0);
 293
 294 #else   /* CONFIG_CPU_SH4A */
 295         ctrl_outl(pc, UBC_BARA);
 296
 297 #ifdef CONFIG_MMU
 298         ctrl_outb(asid, UBC_BASRA);
 299 #endif
 300
 301         ctrl_outl(0, UBC_BAMRA);
 302
 303         if (current_cpu_data.type == CPU_SH7729 ||
 304             current_cpu_data.type == CPU_SH7710 ||
 305             current_cpu_data.type == CPU_SH7712) {
 306                 ctrl_outw(BBR_INST | BBR_READ | BBR_CPU, UBC_BBRA);
 307                 ctrl_outl(BRCR_PCBA | BRCR_PCTE, UBC_BRCR);
 308         } else {
 309                 ctrl_outw(BBR_INST | BBR_READ, UBC_BBRA);
 310                 ctrl_outw(BRCR_PCBA, UBC_BRCR);
 311         }
 312 #endif  /* CONFIG_CPU_SH4A */
 313 }
 314
 315 /*
 316  *      switch_to(x,y) should switch tasks from x to y.
 317  *
 318  */
 319 struct task_struct *__switch_to(struct task_struct *prev,
 320                                 struct task_struct *next)
 321 {
 322 #if defined(CONFIG_SH_FPU)
 323         unlazy_fpu(prev, task_pt_regs(prev));
 324 #endif
 325
 326 #ifdef CONFIG_MMU
 327         /*
 328          * Restore the kernel mode register
 329          *      k7 (r7_bank1)
 330          */
 331         asm volatile("ldc       %0, r7_bank"
 332                      : /* no output */
 333                      : "r" (task_thread_info(next)));
 334 #endif
 335
 336         /* If no tasks are using the UBC, we're done */
 337         if (ubc_usercnt == 0)
 338                 /* If no tasks are using the UBC, we're done */;
 339         else if (next->thread.ubc_pc && next->mm) {
 340                 int asid = 0;
 341 #ifdef CONFIG_MMU
 342                 asid |= cpu_asid(smp_processor_id(), next->mm);
 343 #endif
 344                 ubc_set_tracing(asid, next->thread.ubc_pc);
 345         } else {
 346 #if defined(CONFIG_CPU_SH4A)
 347                 ctrl_outl(UBC_CBR_INIT, UBC_CBR0);
 348                 ctrl_outl(UBC_CRR_INIT, UBC_CRR0);
 349 #else
 350                 ctrl_outw(0, UBC_BBRA);
 351                 ctrl_outw(0, UBC_BBRB);
 352 #endif
 353         }
 354
 355         return prev;
 356 }
 357
 358 asmlinkage int sys_fork(unsigned long r4, unsigned long r5,
 359                         unsigned long r6, unsigned long r7,
 360                         struct pt_regs __regs)
 361 {
 362 #ifdef CONFIG_MMU
 363         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 364         return do_fork(SIGCHLD, regs->regs[15], regs, 0, NULL, NULL);
 365 #else
 366         /* fork almost works, enough to trick you into looking elsewhere :-( */
 367         return -EINVAL;
 368 #endif
 369 }
 370
 371 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
 372                          unsigned long parent_tidptr,
 373                          unsigned long child_tidptr,
 374                          struct pt_regs __regs)
 375 {
 376         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 377         if (!newsp)
 378                 newsp = regs->regs[15];
 379         return do_fork(clone_flags, newsp, regs, 0,
 380                         (int __user *)parent_tidptr,
 381                         (int __user *)child_tidptr);
 382 }
 383
 384 /*
 385  * This is trivial, and on the face of it looks like it
 386  * could equally well be done in user mode.
 387  *
 388  * Not so, for quite unobvious reasons - register pressure.
 389  * In user mode vfork() cannot have a stack frame, and if
 390  * done by calling the "clone()" system call directly, you
 391  * do not have enough call-clobbered registers to hold all
 392  * the information you need.
 393  */
 394 asmlinkage int sys_vfork(unsigned long r4, unsigned long r5,
 395                          unsigned long r6, unsigned long r7,
 396                          struct pt_regs __regs)
 397 {
 398         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 399         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->regs[15], regs,
 400                        0, NULL, NULL);
 401 }
 402
 403 /*
 404  * sys_execve() executes a new program.
 405  */
 406 asmlinkage int sys_execve(char __user *ufilename, char __user * __user *uargv,
 407                           char __user * __user *uenvp, unsigned long r7,
 408                           struct pt_regs __regs)
 409 {
 410         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 411         int error;
 412         char *filename;
 413
 414         filename = getname(ufilename);
 415         error = PTR_ERR(filename);
 416         if (IS_ERR(filename))
 417                 goto out;
 418
 419         error = do_execve(filename, uargv, uenvp, regs);
 420         if (error == 0) {
 421                 task_lock(current);
 422                 current->ptrace &= ~PT_DTRACE;
 423                 task_unlock(current);
 424         }
 425         putname(filename);
 426 out:
 427         return error;
 428 }
 429
 430 unsigned long get_wchan(struct task_struct *p)
 431 {
 432         unsigned long pc;
 433
 434         if (!p || p == current || p->state == TASK_RUNNING)
 435                 return 0;
 436
 437         /*
 438          * The same comment as on the Alpha applies here, too ...
 439          */
 440         pc = thread_saved_pc(p);
 441
 442 #ifdef CONFIG_FRAME_POINTER
 443         if (in_sched_functions(pc)) {
 444                 unsigned long schedule_frame = (unsigned long)p->thread.sp;
 445                 return ((unsigned long *)schedule_frame)[21];
 446         }
 447 #endif
 448
 449         return pc;
 450 }
 451
 452 asmlinkage void break_point_trap(void)
 453 {
 454         /* Clear tracing.  */
 455 #if defined(CONFIG_CPU_SH4A)
 456         ctrl_outl(UBC_CBR_INIT, UBC_CBR0);
 457         ctrl_outl(UBC_CRR_INIT, UBC_CRR0);
 458 #else
 459         ctrl_outw(0, UBC_BBRA);
 460         ctrl_outw(0, UBC_BBRB);
 461 #endif
 462         current->thread.ubc_pc = 0;
 463         ubc_usercnt -= 1;
 464
 465         force_sig(SIGTRAP, current);
 466 }