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 - 2008  Paul Mundt
  11  *
  12  * This file is subject to the terms and conditions of the GNU General Public
  13  * License.  See the file "COPYING" in the main directory of this archive
  14  * for more details.
  15  */
  16 #include <linux/module.h>
  17 #include <linux/mm.h>
  18 #include <linux/elfcore.h>
  19 #include <linux/pm.h>
  20 #include <linux/kallsyms.h>
  21 #include <linux/kexec.h>
  22 #include <linux/kdebug.h>
  23 #include <linux/tick.h>
  24 #include <linux/reboot.h>
  25 #include <linux/fs.h>
  26 #include <linux/preempt.h>
  27 #include <asm/uaccess.h>
  28 #include <asm/mmu_context.h>
  29 #include <asm/pgalloc.h>
  30 #include <asm/system.h>
  31 #include <asm/ubc.h>
  32 #include <asm/fpu.h>
  33 #include <asm/syscalls.h>
  34
  35 static int hlt_counter;
  36 int ubc_usercnt = 0;
  37
  38 void (*pm_idle)(void);
  39 void (*pm_power_off)(void);
  40 EXPORT_SYMBOL(pm_power_off);
  41
  42 static int __init nohlt_setup(char *__unused)
  43 {
  44         hlt_counter = 1;
  45         return 1;
  46 }
  47 __setup("nohlt", nohlt_setup);
  48
  49 static int __init hlt_setup(char *__unused)
  50 {
  51         hlt_counter = 0;
  52         return 1;
  53 }
  54 __setup("hlt", hlt_setup);
  55
  56 static void default_idle(void)
  57 {
  58         if (!hlt_counter) {
  59                 clear_thread_flag(TIF_POLLING_NRFLAG);
  60                 smp_mb__after_clear_bit();
  61                 set_bl_bit();
  62                 while (!need_resched())
  63                         cpu_sleep();
  64                 clear_bl_bit();
  65                 set_thread_flag(TIF_POLLING_NRFLAG);
  66         } else
  67                 while (!need_resched())
  68                         cpu_relax();
  69 }
  70
  71 void cpu_idle(void)
  72 {
  73         set_thread_flag(TIF_POLLING_NRFLAG);
  74
  75         /* endless idle loop with no priority at all */
  76         while (1) {
  77                 void (*idle)(void) = pm_idle;
  78
  79                 if (!idle)
  80                         idle = default_idle;
  81
  82                 tick_nohz_stop_sched_tick(1);
  83                 while (!need_resched())
  84                         idle();
  85                 tick_nohz_restart_sched_tick();
  86
  87                 preempt_enable_no_resched();
  88                 schedule();
  89                 preempt_disable();
  90                 check_pgt_cache();
  91         }
  92 }
  93
  94 void machine_restart(char * __unused)
  95 {
  96         /* SR.BL=1 and invoke address error to let CPU reset (manual reset) */
  97         asm volatile("ldc %0, sr\n\t"
  98                      "mov.l @%1, %0" : : "r" (0x10000000), "r" (0x80000001));
  99 }
 100
 101 void machine_halt(void)
 102 {
 103         local_irq_disable();
 104
 105         while (1)
 106                 cpu_sleep();
 107 }
 108
 109 void machine_power_off(void)
 110 {
 111         if (pm_power_off)
 112                 pm_power_off();
 113 }
 114
 115 void show_regs(struct pt_regs * regs)
 116 {
 117         printk("\n");
 118         printk("Pid : %d, Comm: %20s\n", task_pid_nr(current), current->comm);
 119         printk("CPU : %d    %s  (%s %.*s)\n",
 120                smp_processor_id(), print_tainted(), init_utsname()->release,
 121                (int)strcspn(init_utsname()->version, " "),
 122                init_utsname()->version);
 123
 124         print_symbol("PC is at %s\n", instruction_pointer(regs));
 125         print_symbol("PR is at %s\n", regs->pr);
 126
 127         printk("PC  : %08lx SP  : %08lx SR  : %08lx ",
 128                regs->pc, regs->regs[15], regs->sr);
 129 #ifdef CONFIG_MMU
 130         printk("TEA : %08x\n", ctrl_inl(MMU_TEA));
 131 #else
 132         printk("\n");
 133 #endif
 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         int pid;
 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         pid = do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
 187                       &regs, 0, NULL, NULL);
 188
 189         trace_mark(kernel_arch_kthread_create, "pid %d fn %p", pid, fn);
 190
 191         return pid;
 192 }
 193
 194 /*
 195  * Free current thread data structures etc..
 196  */
 197 void exit_thread(void)
 198 {
 199         if (current->thread.ubc_pc) {
 200                 current->thread.ubc_pc = 0;
 201                 ubc_usercnt -= 1;
 202         }
 203 }
 204
 205 void flush_thread(void)
 206 {
 207 #if defined(CONFIG_SH_FPU)
 208         struct task_struct *tsk = current;
 209         /* Forget lazy FPU state */
 210         clear_fpu(tsk, task_pt_regs(tsk));
 211         clear_used_math();
 212 #endif
 213 }
 214
 215 void release_thread(struct task_struct *dead_task)
 216 {
 217         /* do nothing */
 218 }
 219
 220 /* Fill in the fpu structure for a core dump.. */
 221 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 222 {
 223         int fpvalid = 0;
 224
 225 #if defined(CONFIG_SH_FPU)
 226         struct task_struct *tsk = current;
 227
 228         fpvalid = !!tsk_used_math(tsk);
 229         if (fpvalid)
 230                 fpvalid = !fpregs_get(tsk, NULL, 0,
 231                                       sizeof(struct user_fpu_struct),
 232                                       fpu, NULL);
 233 #endif
 234
 235         return fpvalid;
 236 }
 237
 238 asmlinkage void ret_from_fork(void);
 239
 240 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 241                 unsigned long unused,
 242                 struct task_struct *p, struct pt_regs *regs)
 243 {
 244         struct thread_info *ti = task_thread_info(p);
 245         struct pt_regs *childregs;
 246 #if defined(CONFIG_SH_FPU)
 247         struct task_struct *tsk = current;
 248
 249         unlazy_fpu(tsk, regs);
 250         p->thread.fpu = tsk->thread.fpu;
 251         copy_to_stopped_child_used_math(p);
 252 #endif
 253
 254         childregs = task_pt_regs(p);
 255         *childregs = *regs;
 256
 257         if (user_mode(regs)) {
 258                 childregs->regs[15] = usp;
 259                 ti->addr_limit = USER_DS;
 260         } else {
 261                 childregs->regs[15] = (unsigned long)childregs;
 262                 ti->addr_limit = KERNEL_DS;
 263         }
 264
 265         if (clone_flags & CLONE_SETTLS)
 266                 childregs->gbr = childregs->regs[0];
 267
 268         childregs->regs[0] = 0; /* Set return value for child */
 269
 270         p->thread.sp = (unsigned long) childregs;
 271         p->thread.pc = (unsigned long) ret_from_fork;
 272
 273         p->thread.ubc_pc = 0;
 274
 275         return 0;
 276 }
 277
 278 /* Tracing by user break controller.  */
 279 static void ubc_set_tracing(int asid, unsigned long pc)
 280 {
 281 #if defined(CONFIG_CPU_SH4A)
 282         unsigned long val;
 283
 284         val = (UBC_CBR_ID_INST | UBC_CBR_RW_READ | UBC_CBR_CE);
 285         val |= (UBC_CBR_AIE | UBC_CBR_AIV_SET(asid));
 286
 287         ctrl_outl(val, UBC_CBR0);
 288         ctrl_outl(pc,  UBC_CAR0);
 289         ctrl_outl(0x0, UBC_CAMR0);
 290         ctrl_outl(0x0, UBC_CBCR);
 291
 292         val = (UBC_CRR_RES | UBC_CRR_PCB | UBC_CRR_BIE);
 293         ctrl_outl(val, UBC_CRR0);
 294
 295         /* Read UBC register that we wrote last, for checking update */
 296         val = ctrl_inl(UBC_CRR0);
 297
 298 #else   /* CONFIG_CPU_SH4A */
 299         ctrl_outl(pc, UBC_BARA);
 300
 301 #ifdef CONFIG_MMU
 302         ctrl_outb(asid, UBC_BASRA);
 303 #endif
 304
 305         ctrl_outl(0, UBC_BAMRA);
 306
 307         if (current_cpu_data.type == CPU_SH7729 ||
 308             current_cpu_data.type == CPU_SH7710 ||
 309             current_cpu_data.type == CPU_SH7712) {
 310                 ctrl_outw(BBR_INST | BBR_READ | BBR_CPU, UBC_BBRA);
 311                 ctrl_outl(BRCR_PCBA | BRCR_PCTE, UBC_BRCR);
 312         } else {
 313                 ctrl_outw(BBR_INST | BBR_READ, UBC_BBRA);
 314                 ctrl_outw(BRCR_PCBA, UBC_BRCR);
 315         }
 316 #endif  /* CONFIG_CPU_SH4A */
 317 }
 318
 319 /*
 320  *      switch_to(x,y) should switch tasks from x to y.
 321  *
 322  */
 323 struct task_struct *__switch_to(struct task_struct *prev,
 324                                 struct task_struct *next)
 325 {
 326 #if defined(CONFIG_SH_FPU)
 327         unlazy_fpu(prev, task_pt_regs(prev));
 328 #endif
 329
 330 #ifdef CONFIG_MMU
 331         /*
 332          * Restore the kernel mode register
 333          *      k7 (r7_bank1)
 334          */
 335         asm volatile("ldc       %0, r7_bank"
 336                      : /* no output */
 337                      : "r" (task_thread_info(next)));
 338 #endif
 339
 340         /* If no tasks are using the UBC, we're done */
 341         if (ubc_usercnt == 0)
 342                 /* If no tasks are using the UBC, we're done */;
 343         else if (next->thread.ubc_pc && next->mm) {
 344                 int asid = 0;
 345 #ifdef CONFIG_MMU
 346                 asid |= cpu_asid(smp_processor_id(), next->mm);
 347 #endif
 348                 ubc_set_tracing(asid, next->thread.ubc_pc);
 349         } else {
 350 #if defined(CONFIG_CPU_SH4A)
 351                 ctrl_outl(UBC_CBR_INIT, UBC_CBR0);
 352                 ctrl_outl(UBC_CRR_INIT, UBC_CRR0);
 353 #else
 354                 ctrl_outw(0, UBC_BBRA);
 355                 ctrl_outw(0, UBC_BBRB);
 356 #endif
 357         }
 358
 359         return prev;
 360 }
 361
 362 asmlinkage int sys_fork(unsigned long r4, unsigned long r5,
 363                         unsigned long r6, unsigned long r7,
 364                         struct pt_regs __regs)
 365 {
 366 #ifdef CONFIG_MMU
 367         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 368         return do_fork(SIGCHLD, regs->regs[15], regs, 0, NULL, NULL);
 369 #else
 370         /* fork almost works, enough to trick you into looking elsewhere :-( */
 371         return -EINVAL;
 372 #endif
 373 }
 374
 375 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
 376                          unsigned long parent_tidptr,
 377                          unsigned long child_tidptr,
 378                          struct pt_regs __regs)
 379 {
 380         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 381         if (!newsp)
 382                 newsp = regs->regs[15];
 383         return do_fork(clone_flags, newsp, regs, 0,
 384                         (int __user *)parent_tidptr,
 385                         (int __user *)child_tidptr);
 386 }
 387
 388 /*
 389  * This is trivial, and on the face of it looks like it
 390  * could equally well be done in user mode.
 391  *
 392  * Not so, for quite unobvious reasons - register pressure.
 393  * In user mode vfork() cannot have a stack frame, and if
 394  * done by calling the "clone()" system call directly, you
 395  * do not have enough call-clobbered registers to hold all
 396  * the information you need.
 397  */
 398 asmlinkage int sys_vfork(unsigned long r4, unsigned long r5,
 399                          unsigned long r6, unsigned long r7,
 400                          struct pt_regs __regs)
 401 {
 402         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 403         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->regs[15], regs,
 404                        0, NULL, NULL);
 405 }
 406
 407 /*
 408  * sys_execve() executes a new program.
 409  */
 410 asmlinkage int sys_execve(char __user *ufilename, char __user * __user *uargv,
 411                           char __user * __user *uenvp, unsigned long r7,
 412                           struct pt_regs __regs)
 413 {
 414         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 415         int error;
 416         char *filename;
 417
 418         filename = getname(ufilename);
 419         error = PTR_ERR(filename);
 420         if (IS_ERR(filename))
 421                 goto out;
 422
 423         error = do_execve(filename, uargv, uenvp, regs);
 424         if (error == 0) {
 425                 task_lock(current);
 426                 current->ptrace &= ~PT_DTRACE;
 427                 task_unlock(current);
 428         }
 429         putname(filename);
 430 out:
 431         return error;
 432 }
 433
 434 unsigned long get_wchan(struct task_struct *p)
 435 {
 436         unsigned long pc;
 437
 438         if (!p || p == current || p->state == TASK_RUNNING)
 439                 return 0;
 440
 441         /*
 442          * The same comment as on the Alpha applies here, too ...
 443          */
 444         pc = thread_saved_pc(p);
 445
 446 #ifdef CONFIG_FRAME_POINTER
 447         if (in_sched_functions(pc)) {
 448                 unsigned long schedule_frame = (unsigned long)p->thread.sp;
 449                 return ((unsigned long *)schedule_frame)[21];
 450         }
 451 #endif
 452
 453         return pc;
 454 }
 455
 456 asmlinkage void break_point_trap(void)
 457 {
 458         /* Clear tracing.  */
 459 #if defined(CONFIG_CPU_SH4A)
 460         ctrl_outl(UBC_CBR_INIT, UBC_CBR0);
 461         ctrl_outl(UBC_CRR_INIT, UBC_CRR0);
 462 #else
 463         ctrl_outw(0, UBC_BBRA);
 464         ctrl_outw(0, UBC_BBRB);
 465 #endif
 466         current->thread.ubc_pc = 0;
 467         ubc_usercnt -= 1;
 468
 469         force_sig(SIGTRAP, current);
 470 }