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) 2001-2007 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/fs.h>
  42 #include <linux/module.h>
  43 #include <linux/personality.h>
  44 #include <linux/ptrace.h>
  45 #include <linux/sched.h>
  46 #include <linux/stddef.h>
  47 #include <linux/unistd.h>
  48 #include <linux/kallsyms.h>
  49
  50 #include <asm/io.h>
  51 #include <asm/asm-offsets.h>
  52 #include <asm/pdc.h>
  53 #include <asm/pdc_chassis.h>
  54 #include <asm/pgalloc.h>
  55 #include <asm/uaccess.h>
  56 #include <asm/unwind.h>
  57
  58 /*
  59  * The idle thread. There's no useful work to be
  60  * done, so just try to conserve power and have a
  61  * low exit latency (ie sit in a loop waiting for
  62  * somebody to say that they'd like to reschedule)
  63  */
  64 void cpu_idle(void)
  65 {
  66         set_thread_flag(TIF_POLLING_NRFLAG);
  67
  68         /* endless idle loop with no priority at all */
  69         while (1) {
  70                 while (!need_resched())
  71                         barrier();
  72                 preempt_enable_no_resched();
  73                 schedule();
  74                 preempt_disable();
  75                 check_pgt_cache();
  76         }
  77 }
  78
  79
  80 #define COMMAND_GLOBAL  F_EXTEND(0xfffe0030)
  81 #define CMD_RESET       5       /* reset any module */
  82
  83 /*
  84 ** The Wright Brothers and Gecko systems have a H/W problem
  85 ** (Lasi...'nuf said) may cause a broadcast reset to lockup
  86 ** the system. An HVERSION dependent PDC call was developed
  87 ** to perform a "safe", platform specific broadcast reset instead
  88 ** of kludging up all the code.
  89 **
  90 ** Older machines which do not implement PDC_BROADCAST_RESET will
  91 ** return (with an error) and the regular broadcast reset can be
  92 ** issued. Obviously, if the PDC does implement PDC_BROADCAST_RESET
  93 ** the PDC call will not return (the system will be reset).
  94 */
  95 void machine_restart(char *cmd)
  96 {
  97 #ifdef FASTBOOT_SELFTEST_SUPPORT
  98         /*
  99          ** If user has modified the Firmware Selftest Bitmap,
 100          ** run the tests specified in the bitmap after the
 101          ** system is rebooted w/PDC_DO_RESET.
 102          **
 103          ** ftc_bitmap = 0x1AUL "Skip destructive memory tests"
 104          **
 105          ** Using "directed resets" at each processor with the MEM_TOC
 106          ** vector cleared will also avoid running destructive
 107          ** memory self tests. (Not implemented yet)
 108          */
 109         if (ftc_bitmap) {
 110                 pdc_do_firm_test_reset(ftc_bitmap);
 111         }
 112 #endif
 113         /* set up a new led state on systems shipped with a LED State panel */
 114         pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
 115
 116         /* "Normal" system reset */
 117         pdc_do_reset();
 118
 119         /* Nope...box should reset with just CMD_RESET now */
 120         gsc_writel(CMD_RESET, COMMAND_GLOBAL);
 121
 122         /* Wait for RESET to lay us to rest. */
 123         while (1) ;
 124
 125 }
 126
 127 void machine_halt(void)
 128 {
 129         /*
 130         ** The LED/ChassisCodes are updated by the led_halt()
 131         ** function, called by the reboot notifier chain.
 132         */
 133 }
 134
 135 void (*chassis_power_off)(void);
 136
 137 /*
 138  * This routine is called from sys_reboot to actually turn off the
 139  * machine
 140  */
 141 void machine_power_off(void)
 142 {
 143         /* If there is a registered power off handler, call it. */
 144         if (chassis_power_off)
 145                 chassis_power_off();
 146
 147         /* Put the soft power button back under hardware control.
 148          * If the user had already pressed the power button, the
 149          * following call will immediately power off. */
 150         pdc_soft_power_button(0);
 151
 152         pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
 153
 154         /* It seems we have no way to power the system off via
 155          * software. The user has to press the button himself. */
 156
 157         printk(KERN_EMERG "System shut down completed.\n"
 158                KERN_EMERG "Please power this system off now.");
 159 }
 160
 161 void (*pm_power_off)(void) = machine_power_off;
 162 EXPORT_SYMBOL(pm_power_off);
 163
 164 /*
 165  * Create a kernel thread
 166  */
 167
 168 extern pid_t __kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
 169 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 170 {
 171
 172         /*
 173          * FIXME: Once we are sure we don't need any debug here,
 174          *        kernel_thread can become a #define.
 175          */
 176
 177         return __kernel_thread(fn, arg, flags);
 178 }
 179 EXPORT_SYMBOL(kernel_thread);
 180
 181 /*
 182  * Free current thread data structures etc..
 183  */
 184 void exit_thread(void)
 185 {
 186 }
 187
 188 void flush_thread(void)
 189 {
 190         /* Only needs to handle fpu stuff or perf monitors.
 191         ** REVISIT: several arches implement a "lazy fpu state".
 192         */
 193         set_fs(USER_DS);
 194 }
 195
 196 void release_thread(struct task_struct *dead_task)
 197 {
 198 }
 199
 200 /*
 201  * Fill in the FPU structure for a core dump.
 202  */
 203
 204 int dump_fpu (struct pt_regs * regs, elf_fpregset_t *r)
 205 {
 206         if (regs == NULL)
 207                 return 0;
 208
 209         memcpy(r, regs->fr, sizeof *r);
 210         return 1;
 211 }
 212
 213 int dump_task_fpu (struct task_struct *tsk, elf_fpregset_t *r)
 214 {
 215         memcpy(r, tsk->thread.regs.fr, sizeof(*r));
 216         return 1;
 217 }
 218
 219 /* Note that "fork()" is implemented in terms of clone, with
 220    parameters (SIGCHLD, regs->gr[30], regs). */
 221 int
 222 sys_clone(unsigned long clone_flags, unsigned long usp,
 223           struct pt_regs *regs)
 224 {
 225         /* Arugments from userspace are:
 226            r26 = Clone flags.
 227            r25 = Child stack.
 228            r24 = parent_tidptr.
 229            r23 = Is the TLS storage descriptor
 230            r22 = child_tidptr
 231
 232            However, these last 3 args are only examined
 233            if the proper flags are set. */
 234         int __user *child_tidptr;
 235         int __user *parent_tidptr;
 236
 237         /* usp must be word aligned.  This also prevents users from
 238          * passing in the value 1 (which is the signal for a special
 239          * return for a kernel thread) */
 240         usp = ALIGN(usp, 4);
 241
 242         /* A zero value for usp means use the current stack */
 243         if (usp == 0)
 244           usp = regs->gr[30];
 245
 246         if (clone_flags & CLONE_PARENT_SETTID)
 247           parent_tidptr = (int __user *)regs->gr[24];
 248         else
 249           parent_tidptr = NULL;
 250
 251         if (clone_flags & (CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID))
 252           child_tidptr = (int __user *)regs->gr[22];
 253         else
 254           child_tidptr = NULL;
 255
 256         return do_fork(clone_flags, usp, regs, 0, parent_tidptr, child_tidptr);
 257 }
 258
 259 int
 260 sys_vfork(struct pt_regs *regs)
 261 {
 262         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gr[30], regs, 0, NULL, NULL);
 263 }
 264
 265 int
 266 copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 267             unsigned long unused,       /* in ia64 this is "user_stack_size" */
 268             struct task_struct * p, struct pt_regs * pregs)
 269 {
 270         struct pt_regs * cregs = &(p->thread.regs);
 271         void *stack = task_stack_page(p);
 272
 273         /* We have to use void * instead of a function pointer, because
 274          * function pointers aren't a pointer to the function on 64-bit.
 275          * Make them const so the compiler knows they live in .text */
 276         extern void * const ret_from_kernel_thread;
 277         extern void * const child_return;
 278 #ifdef CONFIG_HPUX
 279         extern void * const hpux_child_return;
 280 #endif
 281
 282         *cregs = *pregs;
 283
 284         /* Set the return value for the child.  Note that this is not
 285            actually restored by the syscall exit path, but we put it
 286            here for consistency in case of signals. */
 287         cregs->gr[28] = 0; /* child */
 288
 289         /*
 290          * We need to differentiate between a user fork and a
 291          * kernel fork. We can't use user_mode, because the
 292          * the syscall path doesn't save iaoq. Right now
 293          * We rely on the fact that kernel_thread passes
 294          * in zero for usp.
 295          */
 296         if (usp == 1) {
 297                 /* kernel thread */
 298                 cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN;
 299                 /* Must exit via ret_from_kernel_thread in order
 300                  * to call schedule_tail()
 301                  */
 302                 cregs->kpc = (unsigned long) &ret_from_kernel_thread;
 303                 /*
 304                  * Copy function and argument to be called from
 305                  * ret_from_kernel_thread.
 306                  */
 307 #ifdef CONFIG_64BIT
 308                 cregs->gr[27] = pregs->gr[27];
 309 #endif
 310                 cregs->gr[26] = pregs->gr[26];
 311                 cregs->gr[25] = pregs->gr[25];
 312         } else {
 313                 /* user thread */
 314                 /*
 315                  * Note that the fork wrappers are responsible
 316                  * for setting gr[21].
 317                  */
 318
 319                 /* Use same stack depth as parent */
 320                 cregs->ksp = (unsigned long)stack
 321                         + (pregs->gr[21] & (THREAD_SIZE - 1));
 322                 cregs->gr[30] = usp;
 323                 if (p->personality == PER_HPUX) {
 324 #ifdef CONFIG_HPUX
 325                         cregs->kpc = (unsigned long) &hpux_child_return;
 326 #else
 327                         BUG();
 328 #endif
 329                 } else {
 330                         cregs->kpc = (unsigned long) &child_return;
 331                 }
 332                 /* Setup thread TLS area from the 4th parameter in clone */
 333                 if (clone_flags & CLONE_SETTLS)
 334                   cregs->cr27 = pregs->gr[23];
 335
 336         }
 337
 338         return 0;
 339 }
 340
 341 unsigned long thread_saved_pc(struct task_struct *t)
 342 {
 343         return t->thread.regs.kpc;
 344 }
 345
 346 /*
 347  * sys_execve() executes a new program.
 348  */
 349
 350 asmlinkage int sys_execve(struct pt_regs *regs)
 351 {
 352         int error;
 353         char *filename;
 354
 355         filename = getname((const char __user *) regs->gr[26]);
 356         error = PTR_ERR(filename);
 357         if (IS_ERR(filename))
 358                 goto out;
 359         error = do_execve(filename, (char __user * __user *) regs->gr[25],
 360                 (char __user * __user *) regs->gr[24], regs);
 361         if (error == 0) {
 362                 task_lock(current);
 363                 current->ptrace &= ~PT_DTRACE;
 364                 task_unlock(current);
 365         }
 366         putname(filename);
 367 out:
 368
 369         return error;
 370 }
 371
 372 extern int __execve(const char *filename, char *const argv[],
 373                 char *const envp[], struct task_struct *task);
 374 int kernel_execve(const char *filename, char *const argv[], char *const envp[])
 375 {
 376         return __execve(filename, argv, envp, current);
 377 }
 378
 379 unsigned long
 380 get_wchan(struct task_struct *p)
 381 {
 382         struct unwind_frame_info info;
 383         unsigned long ip;
 384         int count = 0;
 385
 386         if (!p || p == current || p->state == TASK_RUNNING)
 387                 return 0;
 388
 389         /*
 390          * These bracket the sleeping functions..
 391          */
 392
 393         unwind_frame_init_from_blocked_task(&info, p);
 394         do {
 395                 if (unwind_once(&info) < 0)
 396                         return 0;
 397                 ip = info.ip;
 398                 if (!in_sched_functions(ip))
 399                         return ip;
 400         } while (count++ < 16);
 401         return 0;
 402 }