arch/parisc/kernel/process.c

   1 /*
   2  *    PARISC Architecture-dependent parts of process handling
   3  *    based on the work for i386
   4  *
   5  *    Copyright (C) 1999-2003 Matthew Wilcox <willy at parisc-linux.org>
   6  *    Copyright (C) 2000 Martin K Petersen <mkp at mkp.net>
   7  *    Copyright (C) 2000 John Marvin <jsm at parisc-linux.org>
   8  *    Copyright (C) 2000 David Huggins-Daines <dhd with pobox.org>
   9  *    Copyright (C) 2000-2003 Paul Bame <bame at parisc-linux.org>
  10  *    Copyright (C) 2000 Philipp Rumpf <prumpf with tux.org>
  11  *    Copyright (C) 2000 David Kennedy <dkennedy with linuxcare.com>
  12  *    Copyright (C) 2000 Richard Hirst <rhirst with parisc-linux.org>
  13  *    Copyright (C) 2000 Grant Grundler <grundler with parisc-linux.org>
  14  *    Copyright (C) 2001 Alan Modra <amodra at parisc-linux.org>
  15  *    Copyright (C) 2001-2002 Ryan Bradetich <rbrad at parisc-linux.org>
  16  *    Copyright (C) 2001-2002 Helge Deller <deller at parisc-linux.org>
  17  *    Copyright (C) 2002 Randolph Chung <tausq with parisc-linux.org>
  18  *
  19  *
  20  *    This program is free software; you can redistribute it and/or modify
  21  *    it under the terms of the GNU General Public License as published by
  22  *    the Free Software Foundation; either version 2 of the License, or
  23  *    (at your option) any later version.
  24  *
  25  *    This program is distributed in the hope that it will be useful,
  26  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  27  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  28  *    GNU General Public License for more details.
  29  *
  30  *    You should have received a copy of the GNU General Public License
  31  *    along with this program; if not, write to the Free Software
  32  *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  33  */
  34
  35 #include <stdarg.h>
  36
  37 #include <linux/elf.h>
  38 #include <linux/errno.h>
  39 #include <linux/kernel.h>
  40 #include <linux/mm.h>
  41 #include <linux/module.h>
  42 #include <linux/personality.h>
  43 #include <linux/ptrace.h>
  44 #include <linux/sched.h>
  45 #include <linux/stddef.h>
  46 #include <linux/unistd.h>
  47 #include <linux/kallsyms.h>
  48
  49 #include <asm/io.h>
  50 #include <asm/asm-offsets.h>
  51 #include <asm/pdc.h>
  52 #include <asm/pdc_chassis.h>
  53 #include <asm/pgalloc.h>
  54 #include <asm/uaccess.h>
  55 #include <asm/unwind.h>
  56
  57 static int hlt_counter;
  58
  59 /*
  60  * Power off function, if any
  61  */
  62 void (*pm_power_off)(void);
  63
  64 void disable_hlt(void)
  65 {
  66         hlt_counter++;
  67 }
  68
  69 EXPORT_SYMBOL(disable_hlt);
  70
  71 void enable_hlt(void)
  72 {
  73         hlt_counter--;
  74 }
  75
  76 EXPORT_SYMBOL(enable_hlt);
  77
  78 void default_idle(void)
  79 {
  80         barrier();
  81 }
  82
  83 /*
  84  * The idle thread. There's no useful work to be
  85  * done, so just try to conserve power and have a
  86  * low exit latency (ie sit in a loop waiting for
  87  * somebody to say that they'd like to reschedule)
  88  */
  89 void cpu_idle(void)
  90 {
  91         set_thread_flag(TIF_POLLING_NRFLAG);
  92
  93         /* endless idle loop with no priority at all */
  94         while (1) {
  95                 while (!need_resched())
  96                         barrier();
  97                 preempt_enable_no_resched();
  98                 schedule();
  99                 preempt_disable();
 100                 check_pgt_cache();
 101         }
 102 }
 103
 104
 105 #ifdef __LP64__
 106 #define COMMAND_GLOBAL  0xfffffffffffe0030UL
 107 #else
 108 #define COMMAND_GLOBAL  0xfffe0030
 109 #endif
 110
 111 #define CMD_RESET       5       /* reset any module */
 112
 113 /*
 114 ** The Wright Brothers and Gecko systems have a H/W problem
 115 ** (Lasi...'nuf said) may cause a broadcast reset to lockup
 116 ** the system. An HVERSION dependent PDC call was developed
 117 ** to perform a "safe", platform specific broadcast reset instead
 118 ** of kludging up all the code.
 119 **
 120 ** Older machines which do not implement PDC_BROADCAST_RESET will
 121 ** return (with an error) and the regular broadcast reset can be
 122 ** issued. Obviously, if the PDC does implement PDC_BROADCAST_RESET
 123 ** the PDC call will not return (the system will be reset).
 124 */
 125 void machine_restart(char *cmd)
 126 {
 127 #ifdef FASTBOOT_SELFTEST_SUPPORT
 128         /*
 129          ** If user has modified the Firmware Selftest Bitmap,
 130          ** run the tests specified in the bitmap after the
 131          ** system is rebooted w/PDC_DO_RESET.
 132          **
 133          ** ftc_bitmap = 0x1AUL "Skip destructive memory tests"
 134          **
 135          ** Using "directed resets" at each processor with the MEM_TOC
 136          ** vector cleared will also avoid running destructive
 137          ** memory self tests. (Not implemented yet)
 138          */
 139         if (ftc_bitmap) {
 140                 pdc_do_firm_test_reset(ftc_bitmap);
 141         }
 142 #endif
 143         /* set up a new led state on systems shipped with a LED State panel */
 144         pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
 145
 146         /* "Normal" system reset */
 147         pdc_do_reset();
 148
 149         /* Nope...box should reset with just CMD_RESET now */
 150         gsc_writel(CMD_RESET, COMMAND_GLOBAL);
 151
 152         /* Wait for RESET to lay us to rest. */
 153         while (1) ;
 154
 155 }
 156
 157 void machine_halt(void)
 158 {
 159         /*
 160         ** The LED/ChassisCodes are updated by the led_halt()
 161         ** function, called by the reboot notifier chain.
 162         */
 163 }
 164
 165
 166 /*
 167  * This routine is called from sys_reboot to actually turn off the
 168  * machine
 169  */
 170 void machine_power_off(void)
 171 {
 172         /* If there is a registered power off handler, call it. */
 173         if(pm_power_off)
 174                 pm_power_off();
 175
 176         /* Put the soft power button back under hardware control.
 177          * If the user had already pressed the power button, the
 178          * following call will immediately power off. */
 179         pdc_soft_power_button(0);
 180
 181         pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
 182
 183         /* It seems we have no way to power the system off via
 184          * software. The user has to press the button himself. */
 185
 186         printk(KERN_EMERG "System shut down completed.\n"
 187                KERN_EMERG "Please power this system off now.");
 188 }
 189
 190
 191 /*
 192  * Create a kernel thread
 193  */
 194
 195 extern pid_t __kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
 196 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 197 {
 198
 199         /*
 200          * FIXME: Once we are sure we don't need any debug here,
 201          *        kernel_thread can become a #define.
 202          */
 203
 204         return __kernel_thread(fn, arg, flags);
 205 }
 206 EXPORT_SYMBOL(kernel_thread);
 207
 208 /*
 209  * Free current thread data structures etc..
 210  */
 211 void exit_thread(void)
 212 {
 213 }
 214
 215 void flush_thread(void)
 216 {
 217         /* Only needs to handle fpu stuff or perf monitors.
 218         ** REVISIT: several arches implement a "lazy fpu state".
 219         */
 220         set_fs(USER_DS);
 221 }
 222
 223 void release_thread(struct task_struct *dead_task)
 224 {
 225 }
 226
 227 /*
 228  * Fill in the FPU structure for a core dump.
 229  */
 230
 231 int dump_fpu (struct pt_regs * regs, elf_fpregset_t *r)
 232 {
 233         if (regs == NULL)
 234                 return 0;
 235
 236         memcpy(r, regs->fr, sizeof *r);
 237         return 1;
 238 }
 239
 240 int dump_task_fpu (struct task_struct *tsk, elf_fpregset_t *r)
 241 {
 242         memcpy(r, tsk->thread.regs.fr, sizeof(*r));
 243         return 1;
 244 }
 245
 246 /* Note that "fork()" is implemented in terms of clone, with
 247    parameters (SIGCHLD, regs->gr[30], regs). */
 248 int
 249 sys_clone(unsigned long clone_flags, unsigned long usp,
 250           struct pt_regs *regs)
 251 {
 252         /* Arugments from userspace are:
 253            r26 = Clone flags.
 254            r25 = Child stack.
 255            r24 = parent_tidptr.
 256            r23 = Is the TLS storage descriptor
 257            r22 = child_tidptr
 258
 259            However, these last 3 args are only examined
 260            if the proper flags are set. */
 261         int __user *child_tidptr;
 262         int __user *parent_tidptr;
 263
 264         /* usp must be word aligned.  This also prevents users from
 265          * passing in the value 1 (which is the signal for a special
 266          * return for a kernel thread) */
 267         usp = ALIGN(usp, 4);
 268
 269         /* A zero value for usp means use the current stack */
 270         if (usp == 0)
 271           usp = regs->gr[30];
 272
 273         if (clone_flags & CLONE_PARENT_SETTID)
 274           parent_tidptr = (int __user *)regs->gr[24];
 275         else
 276           parent_tidptr = NULL;
 277
 278         if (clone_flags & (CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID))
 279           child_tidptr = (int __user *)regs->gr[22];
 280         else
 281           child_tidptr = NULL;
 282
 283         return do_fork(clone_flags, usp, regs, 0, parent_tidptr, child_tidptr);
 284 }
 285
 286 int
 287 sys_vfork(struct pt_regs *regs)
 288 {
 289         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gr[30], regs, 0, NULL, NULL);
 290 }
 291
 292 int
 293 copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 294             unsigned long unused,       /* in ia64 this is "user_stack_size" */
 295             struct task_struct * p, struct pt_regs * pregs)
 296 {
 297         struct pt_regs * cregs = &(p->thread.regs);
 298         struct thread_info *ti = p->thread_info;
 299
 300         /* We have to use void * instead of a function pointer, because
 301          * function pointers aren't a pointer to the function on 64-bit.
 302          * Make them const so the compiler knows they live in .text */
 303         extern void * const ret_from_kernel_thread;
 304         extern void * const child_return;
 305 #ifdef CONFIG_HPUX
 306         extern void * const hpux_child_return;
 307 #endif
 308
 309         *cregs = *pregs;
 310
 311         /* Set the return value for the child.  Note that this is not
 312            actually restored by the syscall exit path, but we put it
 313            here for consistency in case of signals. */
 314         cregs->gr[28] = 0; /* child */
 315
 316         /*
 317          * We need to differentiate between a user fork and a
 318          * kernel fork. We can't use user_mode, because the
 319          * the syscall path doesn't save iaoq. Right now
 320          * We rely on the fact that kernel_thread passes
 321          * in zero for usp.
 322          */
 323         if (usp == 1) {
 324                 /* kernel thread */
 325                 cregs->ksp = (((unsigned long)(ti)) + THREAD_SZ_ALGN);
 326                 /* Must exit via ret_from_kernel_thread in order
 327                  * to call schedule_tail()
 328                  */
 329                 cregs->kpc = (unsigned long) &ret_from_kernel_thread;
 330                 /*
 331                  * Copy function and argument to be called from
 332                  * ret_from_kernel_thread.
 333                  */
 334 #ifdef __LP64__
 335                 cregs->gr[27] = pregs->gr[27];
 336 #endif
 337                 cregs->gr[26] = pregs->gr[26];
 338                 cregs->gr[25] = pregs->gr[25];
 339         } else {
 340                 /* user thread */
 341                 /*
 342                  * Note that the fork wrappers are responsible
 343                  * for setting gr[21].
 344                  */
 345
 346                 /* Use same stack depth as parent */
 347                 cregs->ksp = ((unsigned long)(ti))
 348                         + (pregs->gr[21] & (THREAD_SIZE - 1));
 349                 cregs->gr[30] = usp;
 350                 if (p->personality == PER_HPUX) {
 351 #ifdef CONFIG_HPUX
 352                         cregs->kpc = (unsigned long) &hpux_child_return;
 353 #else
 354                         BUG();
 355 #endif
 356                 } else {
 357                         cregs->kpc = (unsigned long) &child_return;
 358                 }
 359                 /* Setup thread TLS area from the 4th parameter in clone */
 360                 if (clone_flags & CLONE_SETTLS)
 361                   cregs->cr27 = pregs->gr[23];
 362
 363         }
 364
 365         return 0;
 366 }
 367
 368 unsigned long thread_saved_pc(struct task_struct *t)
 369 {
 370         return t->thread.regs.kpc;
 371 }
 372
 373 /*
 374  * sys_execve() executes a new program.
 375  */
 376
 377 asmlinkage int sys_execve(struct pt_regs *regs)
 378 {
 379         int error;
 380         char *filename;
 381
 382         filename = getname((const char __user *) regs->gr[26]);
 383         error = PTR_ERR(filename);
 384         if (IS_ERR(filename))
 385                 goto out;
 386         error = do_execve(filename, (char __user **) regs->gr[25],
 387                 (char __user **) regs->gr[24], regs);
 388         if (error == 0) {
 389                 task_lock(current);
 390                 current->ptrace &= ~PT_DTRACE;
 391                 task_unlock(current);
 392         }
 393         putname(filename);
 394 out:
 395
 396         return error;
 397 }
 398
 399 unsigned long
 400 get_wchan(struct task_struct *p)
 401 {
 402         struct unwind_frame_info info;
 403         unsigned long ip;
 404         int count = 0;
 405         /*
 406          * These bracket the sleeping functions..
 407          */
 408
 409         unwind_frame_init_from_blocked_task(&info, p);
 410         do {
 411                 if (unwind_once(&info) < 0)
 412                         return 0;
 413                 ip = info.ip;
 414                 if (!in_sched_functions(ip))
 415                         return ip;
 416         } while (count++ < 16);
 417         return 0;
 418 }