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