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                 stop_critical_timings();
  63
  64                 while (!need_resched())
  65                         cpu_sleep();
  66
  67                 start_critical_timings();
  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(1);
  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: \t\t%s\n", task_pid_nr(current), current->comm);
 123         printk("CPU : %d        \t\t%s  (%s %.*s)\n\n",
 124                smp_processor_id(), print_tainted(), init_utsname()->release,
 125                (int)strcspn(init_utsname()->version, " "),
 126                init_utsname()->version);
 127
 128         print_symbol("PC is at %s\n", instruction_pointer(regs));
 129         print_symbol("PR is at %s\n", regs->pr);
 130
 131         printk("PC  : %08lx SP  : %08lx SR  : %08lx ",
 132                regs->pc, regs->regs[15], regs->sr);
 133 #ifdef CONFIG_MMU
 134         printk("TEA : %08x\n", ctrl_inl(MMU_TEA));
 135 #else
 136         printk("\n");
 137 #endif
 138
 139         printk("R0  : %08lx R1  : %08lx R2  : %08lx R3  : %08lx\n",
 140                regs->regs[0],regs->regs[1],
 141                regs->regs[2],regs->regs[3]);
 142         printk("R4  : %08lx R5  : %08lx R6  : %08lx R7  : %08lx\n",
 143                regs->regs[4],regs->regs[5],
 144                regs->regs[6],regs->regs[7]);
 145         printk("R8  : %08lx R9  : %08lx R10 : %08lx R11 : %08lx\n",
 146                regs->regs[8],regs->regs[9],
 147                regs->regs[10],regs->regs[11]);
 148         printk("R12 : %08lx R13 : %08lx R14 : %08lx\n",
 149                regs->regs[12],regs->regs[13],
 150                regs->regs[14]);
 151         printk("MACH: %08lx MACL: %08lx GBR : %08lx PR  : %08lx\n",
 152                regs->mach, regs->macl, regs->gbr, regs->pr);
 153
 154         show_trace(NULL, (unsigned long *)regs->regs[15], regs);
 155         show_code(regs);
 156 }
 157
 158 /*
 159  * Create a kernel thread
 160  */
 161
 162 /*
 163  * This is the mechanism for creating a new kernel thread.
 164  *
 165  */
 166 extern void kernel_thread_helper(void);
 167 __asm__(".align 5\n"
 168         "kernel_thread_helper:\n\t"
 169         "jsr    @r5\n\t"
 170         " nop\n\t"
 171         "mov.l  1f, r1\n\t"
 172         "jsr    @r1\n\t"
 173         " mov   r0, r4\n\t"
 174         ".align 2\n\t"
 175         "1:.long do_exit");
 176
 177 /* Don't use this in BL=1(cli).  Or else, CPU resets! */
 178 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 179 {
 180         struct pt_regs regs;
 181         int pid;
 182
 183         memset(&regs, 0, sizeof(regs));
 184         regs.regs[4] = (unsigned long)arg;
 185         regs.regs[5] = (unsigned long)fn;
 186
 187         regs.pc = (unsigned long)kernel_thread_helper;
 188         regs.sr = (1 << 30);
 189
 190         /* Ok, create the new process.. */
 191         pid = do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
 192                       &regs, 0, NULL, NULL);
 193
 194         trace_mark(kernel_arch_kthread_create, "pid %d fn %p", pid, fn);
 195
 196         return pid;
 197 }
 198
 199 /*
 200  * Free current thread data structures etc..
 201  */
 202 void exit_thread(void)
 203 {
 204         if (current->thread.ubc_pc) {
 205                 current->thread.ubc_pc = 0;
 206                 ubc_usercnt -= 1;
 207         }
 208 }
 209
 210 void flush_thread(void)
 211 {
 212 #if defined(CONFIG_SH_FPU)
 213         struct task_struct *tsk = current;
 214         /* Forget lazy FPU state */
 215         clear_fpu(tsk, task_pt_regs(tsk));
 216         clear_used_math();
 217 #endif
 218 }
 219
 220 void release_thread(struct task_struct *dead_task)
 221 {
 222         /* do nothing */
 223 }
 224
 225 /* Fill in the fpu structure for a core dump.. */
 226 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 227 {
 228         int fpvalid = 0;
 229
 230 #if defined(CONFIG_SH_FPU)
 231         struct task_struct *tsk = current;
 232
 233         fpvalid = !!tsk_used_math(tsk);
 234         if (fpvalid)
 235                 fpvalid = !fpregs_get(tsk, NULL, 0,
 236                                       sizeof(struct user_fpu_struct),
 237                                       fpu, NULL);
 238 #endif
 239
 240         return fpvalid;
 241 }
 242
 243 asmlinkage void ret_from_fork(void);
 244
 245 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 246                 unsigned long unused,
 247                 struct task_struct *p, struct pt_regs *regs)
 248 {
 249         struct thread_info *ti = task_thread_info(p);
 250         struct pt_regs *childregs;
 251 #if defined(CONFIG_SH_FPU)
 252         struct task_struct *tsk = current;
 253
 254         unlazy_fpu(tsk, regs);
 255         p->thread.fpu = tsk->thread.fpu;
 256         copy_to_stopped_child_used_math(p);
 257 #endif
 258
 259         childregs = task_pt_regs(p);
 260         *childregs = *regs;
 261
 262         if (user_mode(regs)) {
 263                 childregs->regs[15] = usp;
 264                 ti->addr_limit = USER_DS;
 265         } else {
 266                 childregs->regs[15] = (unsigned long)childregs;
 267                 ti->addr_limit = KERNEL_DS;
 268         }
 269
 270         if (clone_flags & CLONE_SETTLS)
 271                 childregs->gbr = childregs->regs[0];
 272
 273         childregs->regs[0] = 0; /* Set return value for child */
 274
 275         p->thread.sp = (unsigned long) childregs;
 276         p->thread.pc = (unsigned long) ret_from_fork;
 277
 278         p->thread.ubc_pc = 0;
 279
 280         return 0;
 281 }
 282
 283 /* Tracing by user break controller.  */
 284 static void ubc_set_tracing(int asid, unsigned long pc)
 285 {
 286 #if defined(CONFIG_CPU_SH4A)
 287         unsigned long val;
 288
 289         val = (UBC_CBR_ID_INST | UBC_CBR_RW_READ | UBC_CBR_CE);
 290         val |= (UBC_CBR_AIE | UBC_CBR_AIV_SET(asid));
 291
 292         ctrl_outl(val, UBC_CBR0);
 293         ctrl_outl(pc,  UBC_CAR0);
 294         ctrl_outl(0x0, UBC_CAMR0);
 295         ctrl_outl(0x0, UBC_CBCR);
 296
 297         val = (UBC_CRR_RES | UBC_CRR_PCB | UBC_CRR_BIE);
 298         ctrl_outl(val, UBC_CRR0);
 299
 300         /* Read UBC register that we wrote last, for checking update */
 301         val = ctrl_inl(UBC_CRR0);
 302
 303 #else   /* CONFIG_CPU_SH4A */
 304         ctrl_outl(pc, UBC_BARA);
 305
 306 #ifdef CONFIG_MMU
 307         ctrl_outb(asid, UBC_BASRA);
 308 #endif
 309
 310         ctrl_outl(0, UBC_BAMRA);
 311
 312         if (current_cpu_data.type == CPU_SH7729 ||
 313             current_cpu_data.type == CPU_SH7710 ||
 314             current_cpu_data.type == CPU_SH7712) {
 315                 ctrl_outw(BBR_INST | BBR_READ | BBR_CPU, UBC_BBRA);
 316                 ctrl_outl(BRCR_PCBA | BRCR_PCTE, UBC_BRCR);
 317         } else {
 318                 ctrl_outw(BBR_INST | BBR_READ, UBC_BBRA);
 319                 ctrl_outw(BRCR_PCBA, UBC_BRCR);
 320         }
 321 #endif  /* CONFIG_CPU_SH4A */
 322 }
 323
 324 /*
 325  *      switch_to(x,y) should switch tasks from x to y.
 326  *
 327  */
 328 struct task_struct *__switch_to(struct task_struct *prev,
 329                                 struct task_struct *next)
 330 {
 331 #if defined(CONFIG_SH_FPU)
 332         unlazy_fpu(prev, task_pt_regs(prev));
 333 #endif
 334
 335 #ifdef CONFIG_MMU
 336         /*
 337          * Restore the kernel mode register
 338          *      k7 (r7_bank1)
 339          */
 340         asm volatile("ldc       %0, r7_bank"
 341                      : /* no output */
 342                      : "r" (task_thread_info(next)));
 343 #endif
 344
 345         /* If no tasks are using the UBC, we're done */
 346         if (ubc_usercnt == 0)
 347                 /* If no tasks are using the UBC, we're done */;
 348         else if (next->thread.ubc_pc && next->mm) {
 349                 int asid = 0;
 350 #ifdef CONFIG_MMU
 351                 asid |= cpu_asid(smp_processor_id(), next->mm);
 352 #endif
 353                 ubc_set_tracing(asid, next->thread.ubc_pc);
 354         } else {
 355 #if defined(CONFIG_CPU_SH4A)
 356                 ctrl_outl(UBC_CBR_INIT, UBC_CBR0);
 357                 ctrl_outl(UBC_CRR_INIT, UBC_CRR0);
 358 #else
 359                 ctrl_outw(0, UBC_BBRA);
 360                 ctrl_outw(0, UBC_BBRB);
 361 #endif
 362         }
 363
 364         return prev;
 365 }
 366
 367 asmlinkage int sys_fork(unsigned long r4, unsigned long r5,
 368                         unsigned long r6, unsigned long r7,
 369                         struct pt_regs __regs)
 370 {
 371 #ifdef CONFIG_MMU
 372         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 373         return do_fork(SIGCHLD, regs->regs[15], regs, 0, NULL, NULL);
 374 #else
 375         /* fork almost works, enough to trick you into looking elsewhere :-( */
 376         return -EINVAL;
 377 #endif
 378 }
 379
 380 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
 381                          unsigned long parent_tidptr,
 382                          unsigned long child_tidptr,
 383                          struct pt_regs __regs)
 384 {
 385         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 386         if (!newsp)
 387                 newsp = regs->regs[15];
 388         return do_fork(clone_flags, newsp, regs, 0,
 389                         (int __user *)parent_tidptr,
 390                         (int __user *)child_tidptr);
 391 }
 392
 393 /*
 394  * This is trivial, and on the face of it looks like it
 395  * could equally well be done in user mode.
 396  *
 397  * Not so, for quite unobvious reasons - register pressure.
 398  * In user mode vfork() cannot have a stack frame, and if
 399  * done by calling the "clone()" system call directly, you
 400  * do not have enough call-clobbered registers to hold all
 401  * the information you need.
 402  */
 403 asmlinkage int sys_vfork(unsigned long r4, unsigned long r5,
 404                          unsigned long r6, unsigned long r7,
 405                          struct pt_regs __regs)
 406 {
 407         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 408         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->regs[15], regs,
 409                        0, NULL, NULL);
 410 }
 411
 412 /*
 413  * sys_execve() executes a new program.
 414  */
 415 asmlinkage int sys_execve(char __user *ufilename, char __user * __user *uargv,
 416                           char __user * __user *uenvp, unsigned long r7,
 417                           struct pt_regs __regs)
 418 {
 419         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 420         int error;
 421         char *filename;
 422
 423         filename = getname(ufilename);
 424         error = PTR_ERR(filename);
 425         if (IS_ERR(filename))
 426                 goto out;
 427
 428         error = do_execve(filename, uargv, uenvp, regs);
 429         if (error == 0) {
 430                 task_lock(current);
 431                 current->ptrace &= ~PT_DTRACE;
 432                 task_unlock(current);
 433         }
 434         putname(filename);
 435 out:
 436         return error;
 437 }
 438
 439 unsigned long get_wchan(struct task_struct *p)
 440 {
 441         unsigned long pc;
 442
 443         if (!p || p == current || p->state == TASK_RUNNING)
 444                 return 0;
 445
 446         /*
 447          * The same comment as on the Alpha applies here, too ...
 448          */
 449         pc = thread_saved_pc(p);
 450
 451 #ifdef CONFIG_FRAME_POINTER
 452         if (in_sched_functions(pc)) {
 453                 unsigned long schedule_frame = (unsigned long)p->thread.sp;
 454                 return ((unsigned long *)schedule_frame)[21];
 455         }
 456 #endif
 457
 458         return pc;
 459 }
 460
 461 asmlinkage void break_point_trap(void)
 462 {
 463         /* Clear tracing.  */
 464 #if defined(CONFIG_CPU_SH4A)
 465         ctrl_outl(UBC_CBR_INIT, UBC_CBR0);
 466         ctrl_outl(UBC_CRR_INIT, UBC_CRR0);
 467 #else
 468         ctrl_outw(0, UBC_BBRA);
 469         ctrl_outw(0, UBC_BBRB);
 470 #endif
 471         current->thread.ubc_pc = 0;
 472         ubc_usercnt -= 1;
 473
 474         force_sig(SIGTRAP, current);
 475 }