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         /* endless idle loop with no priority at all */
  92         while (1) {
  93                 while (!need_resched())
  94                         barrier();
  95                 preempt_enable_no_resched();
  96                 schedule();
  97                 preempt_disable();
  98                 check_pgt_cache();
  99         }
 100 }
 101
 102
 103 #ifdef __LP64__
 104 #define COMMAND_GLOBAL  0xfffffffffffe0030UL
 105 #else
 106 #define COMMAND_GLOBAL  0xfffe0030
 107 #endif
 108
 109 #define CMD_RESET       5       /* reset any module */
 110
 111 /*
 112 ** The Wright Brothers and Gecko systems have a H/W problem
 113 ** (Lasi...'nuf said) may cause a broadcast reset to lockup
 114 ** the system. An HVERSION dependent PDC call was developed
 115 ** to perform a "safe", platform specific broadcast reset instead
 116 ** of kludging up all the code.
 117 **
 118 ** Older machines which do not implement PDC_BROADCAST_RESET will
 119 ** return (with an error) and the regular broadcast reset can be
 120 ** issued. Obviously, if the PDC does implement PDC_BROADCAST_RESET
 121 ** the PDC call will not return (the system will be reset).
 122 */
 123 void machine_restart(char *cmd)
 124 {
 125 #ifdef FASTBOOT_SELFTEST_SUPPORT
 126         /*
 127          ** If user has modified the Firmware Selftest Bitmap,
 128          ** run the tests specified in the bitmap after the
 129          ** system is rebooted w/PDC_DO_RESET.
 130          **
 131          ** ftc_bitmap = 0x1AUL "Skip destructive memory tests"
 132          **
 133          ** Using "directed resets" at each processor with the MEM_TOC
 134          ** vector cleared will also avoid running destructive
 135          ** memory self tests. (Not implemented yet)
 136          */
 137         if (ftc_bitmap) {
 138                 pdc_do_firm_test_reset(ftc_bitmap);
 139         }
 140 #endif
 141         /* set up a new led state on systems shipped with a LED State panel */
 142         pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
 143
 144         /* "Normal" system reset */
 145         pdc_do_reset();
 146
 147         /* Nope...box should reset with just CMD_RESET now */
 148         gsc_writel(CMD_RESET, COMMAND_GLOBAL);
 149
 150         /* Wait for RESET to lay us to rest. */
 151         while (1) ;
 152
 153 }
 154
 155 void machine_halt(void)
 156 {
 157         /*
 158         ** The LED/ChassisCodes are updated by the led_halt()
 159         ** function, called by the reboot notifier chain.
 160         */
 161 }
 162
 163
 164 /*
 165  * This routine is called from sys_reboot to actually turn off the
 166  * machine
 167  */
 168 void machine_power_off(void)
 169 {
 170         /* If there is a registered power off handler, call it. */
 171         if(pm_power_off)
 172                 pm_power_off();
 173
 174         /* Put the soft power button back under hardware control.
 175          * If the user had already pressed the power button, the
 176          * following call will immediately power off. */
 177         pdc_soft_power_button(0);
 178
 179         pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
 180
 181         /* It seems we have no way to power the system off via
 182          * software. The user has to press the button himself. */
 183
 184         printk(KERN_EMERG "System shut down completed.\n"
 185                KERN_EMERG "Please power this system off now.");
 186 }
 187
 188
 189 /*
 190  * Create a kernel thread
 191  */
 192
 193 extern pid_t __kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
 194 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 195 {
 196
 197         /*
 198          * FIXME: Once we are sure we don't need any debug here,
 199          *        kernel_thread can become a #define.
 200          */
 201
 202         return __kernel_thread(fn, arg, flags);
 203 }
 204 EXPORT_SYMBOL(kernel_thread);
 205
 206 /*
 207  * Free current thread data structures etc..
 208  */
 209 void exit_thread(void)
 210 {
 211 }
 212
 213 void flush_thread(void)
 214 {
 215         /* Only needs to handle fpu stuff or perf monitors.
 216         ** REVISIT: several arches implement a "lazy fpu state".
 217         */
 218         set_fs(USER_DS);
 219 }
 220
 221 void release_thread(struct task_struct *dead_task)
 222 {
 223 }
 224
 225 /*
 226  * Fill in the FPU structure for a core dump.
 227  */
 228
 229 int dump_fpu (struct pt_regs * regs, elf_fpregset_t *r)
 230 {
 231         if (regs == NULL)
 232                 return 0;
 233
 234         memcpy(r, regs->fr, sizeof *r);
 235         return 1;
 236 }
 237
 238 int dump_task_fpu (struct task_struct *tsk, elf_fpregset_t *r)
 239 {
 240         memcpy(r, tsk->thread.regs.fr, sizeof(*r));
 241         return 1;
 242 }
 243
 244 /* Note that "fork()" is implemented in terms of clone, with
 245    parameters (SIGCHLD, regs->gr[30], regs). */
 246 int
 247 sys_clone(unsigned long clone_flags, unsigned long usp,
 248           struct pt_regs *regs)
 249 {
 250         /* Arugments from userspace are:
 251            r26 = Clone flags.
 252            r25 = Child stack.
 253            r24 = parent_tidptr.
 254            r23 = Is the TLS storage descriptor
 255            r22 = child_tidptr
 256
 257            However, these last 3 args are only examined
 258            if the proper flags are set. */
 259         int __user *child_tidptr;
 260         int __user *parent_tidptr;
 261
 262         /* usp must be word aligned.  This also prevents users from
 263          * passing in the value 1 (which is the signal for a special
 264          * return for a kernel thread) */
 265         usp = ALIGN(usp, 4);
 266
 267         /* A zero value for usp means use the current stack */
 268         if (usp == 0)
 269           usp = regs->gr[30];
 270
 271         if (clone_flags & CLONE_PARENT_SETTID)
 272           parent_tidptr = (int __user *)regs->gr[24];
 273         else
 274           parent_tidptr = NULL;
 275
 276         if (clone_flags & (CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID))
 277           child_tidptr = (int __user *)regs->gr[22];
 278         else
 279           child_tidptr = NULL;
 280
 281         return do_fork(clone_flags, usp, regs, 0, parent_tidptr, child_tidptr);
 282 }
 283
 284 int
 285 sys_vfork(struct pt_regs *regs)
 286 {
 287         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gr[30], regs, 0, NULL, NULL);
 288 }
 289
 290 int
 291 copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 292             unsigned long unused,       /* in ia64 this is "user_stack_size" */
 293             struct task_struct * p, struct pt_regs * pregs)
 294 {
 295         struct pt_regs * cregs = &(p->thread.regs);
 296         struct thread_info *ti = p->thread_info;
 297
 298         /* We have to use void * instead of a function pointer, because
 299          * function pointers aren't a pointer to the function on 64-bit.
 300          * Make them const so the compiler knows they live in .text */
 301         extern void * const ret_from_kernel_thread;
 302         extern void * const child_return;
 303 #ifdef CONFIG_HPUX
 304         extern void * const hpux_child_return;
 305 #endif
 306
 307         *cregs = *pregs;
 308
 309         /* Set the return value for the child.  Note that this is not
 310            actually restored by the syscall exit path, but we put it
 311            here for consistency in case of signals. */
 312         cregs->gr[28] = 0; /* child */
 313
 314         /*
 315          * We need to differentiate between a user fork and a
 316          * kernel fork. We can't use user_mode, because the
 317          * the syscall path doesn't save iaoq. Right now
 318          * We rely on the fact that kernel_thread passes
 319          * in zero for usp.
 320          */
 321         if (usp == 1) {
 322                 /* kernel thread */
 323                 cregs->ksp = (((unsigned long)(ti)) + THREAD_SZ_ALGN);
 324                 /* Must exit via ret_from_kernel_thread in order
 325                  * to call schedule_tail()
 326                  */
 327                 cregs->kpc = (unsigned long) &ret_from_kernel_thread;
 328                 /*
 329                  * Copy function and argument to be called from
 330                  * ret_from_kernel_thread.
 331                  */
 332 #ifdef __LP64__
 333                 cregs->gr[27] = pregs->gr[27];
 334 #endif
 335                 cregs->gr[26] = pregs->gr[26];
 336                 cregs->gr[25] = pregs->gr[25];
 337         } else {
 338                 /* user thread */
 339                 /*
 340                  * Note that the fork wrappers are responsible
 341                  * for setting gr[21].
 342                  */
 343
 344                 /* Use same stack depth as parent */
 345                 cregs->ksp = ((unsigned long)(ti))
 346                         + (pregs->gr[21] & (THREAD_SIZE - 1));
 347                 cregs->gr[30] = usp;
 348                 if (p->personality == PER_HPUX) {
 349 #ifdef CONFIG_HPUX
 350                         cregs->kpc = (unsigned long) &hpux_child_return;
 351 #else
 352                         BUG();
 353 #endif
 354                 } else {
 355                         cregs->kpc = (unsigned long) &child_return;
 356                 }
 357                 /* Setup thread TLS area from the 4th parameter in clone */
 358                 if (clone_flags & CLONE_SETTLS)
 359                   cregs->cr27 = pregs->gr[23];
 360
 361         }
 362
 363         return 0;
 364 }
 365
 366 unsigned long thread_saved_pc(struct task_struct *t)
 367 {
 368         return t->thread.regs.kpc;
 369 }
 370
 371 /*
 372  * sys_execve() executes a new program.
 373  */
 374
 375 asmlinkage int sys_execve(struct pt_regs *regs)
 376 {
 377         int error;
 378         char *filename;
 379
 380         filename = getname((const char __user *) regs->gr[26]);
 381         error = PTR_ERR(filename);
 382         if (IS_ERR(filename))
 383                 goto out;
 384         error = do_execve(filename, (char __user **) regs->gr[25],
 385                 (char __user **) regs->gr[24], regs);
 386         if (error == 0) {
 387                 task_lock(current);
 388                 current->ptrace &= ~PT_DTRACE;
 389                 task_unlock(current);
 390         }
 391         putname(filename);
 392 out:
 393
 394         return error;
 395 }
 396
 397 unsigned long
 398 get_wchan(struct task_struct *p)
 399 {
 400         struct unwind_frame_info info;
 401         unsigned long ip;
 402         int count = 0;
 403         /*
 404          * These bracket the sleeping functions..
 405          */
 406
 407         unwind_frame_init_from_blocked_task(&info, p);
 408         do {
 409                 if (unwind_once(&info) < 0)
 410                         return 0;
 411                 ip = info.ip;
 412                 if (!in_sched_functions(ip))
 413                         return ip;
 414         } while (count++ < 16);
 415         return 0;
 416 }