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/slab.h>
  47 #include <linux/stddef.h>
  48 #include <linux/unistd.h>
  49 #include <linux/kallsyms.h>
  50 #include <linux/uaccess.h>
  51 #include <linux/rcupdate.h>
  52
  53 #include <asm/io.h>
  54 #include <asm/asm-offsets.h>
  55 #include <asm/pdc.h>
  56 #include <asm/pdc_chassis.h>
  57 #include <asm/pgalloc.h>
  58 #include <asm/unwind.h>
  59 #include <asm/sections.h>
  60
  61 /*
  62  * The idle thread. There's no useful work to be
  63  * done, so just try to conserve power and have a
  64  * low exit latency (ie sit in a loop waiting for
  65  * somebody to say that they'd like to reschedule)
  66  */
  67 void cpu_idle(void)
  68 {
  69         set_thread_flag(TIF_POLLING_NRFLAG);
  70
  71         /* endless idle loop with no priority at all */
  72         while (1) {
  73                 rcu_idle_enter();
  74                 while (!need_resched())
  75                         barrier();
  76                 rcu_idle_exit();
  77                 schedule_preempt_disabled();
  78                 check_pgt_cache();
  79         }
  80 }
  81
  82
  83 #define COMMAND_GLOBAL  F_EXTEND(0xfffe0030)
  84 #define CMD_RESET       5       /* reset any module */
  85
  86 /*
  87 ** The Wright Brothers and Gecko systems have a H/W problem
  88 ** (Lasi...'nuf said) may cause a broadcast reset to lockup
  89 ** the system. An HVERSION dependent PDC call was developed
  90 ** to perform a "safe", platform specific broadcast reset instead
  91 ** of kludging up all the code.
  92 **
  93 ** Older machines which do not implement PDC_BROADCAST_RESET will
  94 ** return (with an error) and the regular broadcast reset can be
  95 ** issued. Obviously, if the PDC does implement PDC_BROADCAST_RESET
  96 ** the PDC call will not return (the system will be reset).
  97 */
  98 void machine_restart(char *cmd)
  99 {
 100 #ifdef FASTBOOT_SELFTEST_SUPPORT
 101         /*
 102          ** If user has modified the Firmware Selftest Bitmap,
 103          ** run the tests specified in the bitmap after the
 104          ** system is rebooted w/PDC_DO_RESET.
 105          **
 106          ** ftc_bitmap = 0x1AUL "Skip destructive memory tests"
 107          **
 108          ** Using "directed resets" at each processor with the MEM_TOC
 109          ** vector cleared will also avoid running destructive
 110          ** memory self tests. (Not implemented yet)
 111          */
 112         if (ftc_bitmap) {
 113                 pdc_do_firm_test_reset(ftc_bitmap);
 114         }
 115 #endif
 116         /* set up a new led state on systems shipped with a LED State panel */
 117         pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
 118
 119         /* "Normal" system reset */
 120         pdc_do_reset();
 121
 122         /* Nope...box should reset with just CMD_RESET now */
 123         gsc_writel(CMD_RESET, COMMAND_GLOBAL);
 124
 125         /* Wait for RESET to lay us to rest. */
 126         while (1) ;
 127
 128 }
 129
 130 void machine_halt(void)
 131 {
 132         /*
 133         ** The LED/ChassisCodes are updated by the led_halt()
 134         ** function, called by the reboot notifier chain.
 135         */
 136 }
 137
 138 void (*chassis_power_off)(void);
 139
 140 /*
 141  * This routine is called from sys_reboot to actually turn off the
 142  * machine
 143  */
 144 void machine_power_off(void)
 145 {
 146         /* If there is a registered power off handler, call it. */
 147         if (chassis_power_off)
 148                 chassis_power_off();
 149
 150         /* Put the soft power button back under hardware control.
 151          * If the user had already pressed the power button, the
 152          * following call will immediately power off. */
 153         pdc_soft_power_button(0);
 154
 155         pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
 156
 157         /* It seems we have no way to power the system off via
 158          * software. The user has to press the button himself. */
 159
 160         printk(KERN_EMERG "System shut down completed.\n"
 161                "Please power this system off now.");
 162 }
 163
 164 void (*pm_power_off)(void) = machine_power_off;
 165 EXPORT_SYMBOL(pm_power_off);
 166
 167 /*
 168  * Create a kernel thread
 169  */
 170
 171 extern pid_t __kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
 172 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 173 {
 174
 175         /*
 176          * FIXME: Once we are sure we don't need any debug here,
 177          *        kernel_thread can become a #define.
 178          */
 179
 180         return __kernel_thread(fn, arg, flags);
 181 }
 182 EXPORT_SYMBOL(kernel_thread);
 183
 184 /*
 185  * Free current thread data structures etc..
 186  */
 187 void exit_thread(void)
 188 {
 189 }
 190
 191 void flush_thread(void)
 192 {
 193         /* Only needs to handle fpu stuff or perf monitors.
 194         ** REVISIT: several arches implement a "lazy fpu state".
 195         */
 196 }
 197
 198 void release_thread(struct task_struct *dead_task)
 199 {
 200 }
 201
 202 /*
 203  * Fill in the FPU structure for a core dump.
 204  */
 205
 206 int dump_fpu (struct pt_regs * regs, elf_fpregset_t *r)
 207 {
 208         if (regs == NULL)
 209                 return 0;
 210
 211         memcpy(r, regs->fr, sizeof *r);
 212         return 1;
 213 }
 214
 215 int dump_task_fpu (struct task_struct *tsk, elf_fpregset_t *r)
 216 {
 217         memcpy(r, tsk->thread.regs.fr, sizeof(*r));
 218         return 1;
 219 }
 220
 221 /* Note that "fork()" is implemented in terms of clone, with
 222    parameters (SIGCHLD, regs->gr[30], regs). */
 223 int
 224 sys_clone(unsigned long clone_flags, unsigned long usp,
 225           struct pt_regs *regs)
 226 {
 227         /* Arugments from userspace are:
 228            r26 = Clone flags.
 229            r25 = Child stack.
 230            r24 = parent_tidptr.
 231            r23 = Is the TLS storage descriptor
 232            r22 = child_tidptr
 233
 234            However, these last 3 args are only examined
 235            if the proper flags are set. */
 236         int __user *parent_tidptr = (int __user *)regs->gr[24];
 237         int __user *child_tidptr  = (int __user *)regs->gr[22];
 238
 239         /* usp must be word aligned.  This also prevents users from
 240          * passing in the value 1 (which is the signal for a special
 241          * return for a kernel thread) */
 242         usp = ALIGN(usp, 4);
 243
 244         /* A zero value for usp means use the current stack */
 245         if (usp == 0)
 246           usp = regs->gr[30];
 247
 248         return do_fork(clone_flags, usp, regs, 0, parent_tidptr, child_tidptr);
 249 }
 250
 251 int
 252 sys_vfork(struct pt_regs *regs)
 253 {
 254         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gr[30], regs, 0, NULL, NULL);
 255 }
 256
 257 int
 258 copy_thread(unsigned long clone_flags, unsigned long usp,
 259             unsigned long unused,       /* in ia64 this is "user_stack_size" */
 260             struct task_struct * p, struct pt_regs * pregs)
 261 {
 262         struct pt_regs * cregs = &(p->thread.regs);
 263         void *stack = task_stack_page(p);
 264
 265         /* We have to use void * instead of a function pointer, because
 266          * function pointers aren't a pointer to the function on 64-bit.
 267          * Make them const so the compiler knows they live in .text */
 268         extern void * const ret_from_kernel_thread;
 269         extern void * const child_return;
 270 #ifdef CONFIG_HPUX
 271         extern void * const hpux_child_return;
 272 #endif
 273
 274         *cregs = *pregs;
 275
 276         /* Set the return value for the child.  Note that this is not
 277            actually restored by the syscall exit path, but we put it
 278            here for consistency in case of signals. */
 279         cregs->gr[28] = 0; /* child */
 280
 281         /*
 282          * We need to differentiate between a user fork and a
 283          * kernel fork. We can't use user_mode, because the
 284          * the syscall path doesn't save iaoq. Right now
 285          * We rely on the fact that kernel_thread passes
 286          * in zero for usp.
 287          */
 288         if (usp == 1) {
 289                 /* kernel thread */
 290                 cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN;
 291                 /* Must exit via ret_from_kernel_thread in order
 292                  * to call schedule_tail()
 293                  */
 294                 cregs->kpc = (unsigned long) &ret_from_kernel_thread;
 295                 /*
 296                  * Copy function and argument to be called from
 297                  * ret_from_kernel_thread.
 298                  */
 299 #ifdef CONFIG_64BIT
 300                 cregs->gr[27] = pregs->gr[27];
 301 #endif
 302                 cregs->gr[26] = pregs->gr[26];
 303                 cregs->gr[25] = pregs->gr[25];
 304         } else {
 305                 /* user thread */
 306                 /*
 307                  * Note that the fork wrappers are responsible
 308                  * for setting gr[21].
 309                  */
 310
 311                 /* Use same stack depth as parent */
 312                 cregs->ksp = (unsigned long)stack
 313                         + (pregs->gr[21] & (THREAD_SIZE - 1));
 314                 cregs->gr[30] = usp;
 315                 if (personality(p->personality) == PER_HPUX) {
 316 #ifdef CONFIG_HPUX
 317                         cregs->kpc = (unsigned long) &hpux_child_return;
 318 #else
 319                         BUG();
 320 #endif
 321                 } else {
 322                         cregs->kpc = (unsigned long) &child_return;
 323                 }
 324                 /* Setup thread TLS area from the 4th parameter in clone */
 325                 if (clone_flags & CLONE_SETTLS)
 326                   cregs->cr27 = pregs->gr[23];
 327
 328         }
 329
 330         return 0;
 331 }
 332
 333 unsigned long thread_saved_pc(struct task_struct *t)
 334 {
 335         return t->thread.regs.kpc;
 336 }
 337
 338 /*
 339  * sys_execve() executes a new program.
 340  */
 341
 342 asmlinkage int sys_execve(struct pt_regs *regs)
 343 {
 344         int error;
 345         struct filename *filename;
 346
 347         filename = getname((const char __user *) regs->gr[26]);
 348         error = PTR_ERR(filename);
 349         if (IS_ERR(filename))
 350                 goto out;
 351         error = do_execve(filename->name,
 352                           (const char __user *const __user *) regs->gr[25],
 353                           (const char __user *const __user *) regs->gr[24],
 354                           regs);
 355         putname(filename);
 356 out:
 357
 358         return error;
 359 }
 360
 361 extern int __execve(const char *filename,
 362                     const char *const argv[],
 363                     const char *const envp[], struct task_struct *task);
 364 int kernel_execve(const char *filename,
 365                   const char *const argv[],
 366                   const char *const envp[])
 367 {
 368         return __execve(filename, argv, envp, current);
 369 }
 370
 371 unsigned long
 372 get_wchan(struct task_struct *p)
 373 {
 374         struct unwind_frame_info info;
 375         unsigned long ip;
 376         int count = 0;
 377
 378         if (!p || p == current || p->state == TASK_RUNNING)
 379                 return 0;
 380
 381         /*
 382          * These bracket the sleeping functions..
 383          */
 384
 385         unwind_frame_init_from_blocked_task(&info, p);
 386         do {
 387                 if (unwind_once(&info) < 0)
 388                         return 0;
 389                 ip = info.ip;
 390                 if (!in_sched_functions(ip))
 391                         return ip;
 392         } while (count++ < 16);
 393         return 0;
 394 }
 395
 396 #ifdef CONFIG_64BIT
 397 void *dereference_function_descriptor(void *ptr)
 398 {
 399         Elf64_Fdesc *desc = ptr;
 400         void *p;
 401
 402         if (!probe_kernel_address(&desc->addr, p))
 403                 ptr = p;
 404         return ptr;
 405 }
 406 #endif