arch/cris/kernel/process.c

   1 /* $Id: process.c,v 1.17 2004/04/05 13:53:48 starvik Exp $
   2  *
   3  *  linux/arch/cris/kernel/process.c
   4  *
   5  *  Copyright (C) 1995  Linus Torvalds
   6  *  Copyright (C) 2000-2002  Axis Communications AB
   7  *
   8  *  Authors:   Bjorn Wesen (bjornw@axis.com)
   9  *
  10  *  $Log: process.c,v $
  11  *  Revision 1.17  2004/04/05 13:53:48  starvik
  12  *  Merge of Linux 2.6.5
  13  *
  14  *  Revision 1.16  2003/10/27 08:04:33  starvik
  15  *  Merge of Linux 2.6.0-test9
  16  *
  17  *  Revision 1.15  2003/09/11 07:29:52  starvik
  18  *  Merge of Linux 2.6.0-test5
  19  *
  20  *  Revision 1.14  2003/06/10 10:21:12  johana
  21  *  Moved thread_saved_pc() from arch/cris/kernel/process.c to
  22  *  subarch specific process.c. arch-v32 has an erp, no irp.
  23  *
  24  *  Revision 1.13  2003/04/09 05:20:47  starvik
  25  *  Merge of Linux 2.5.67
  26  *
  27  *  Revision 1.12  2002/12/11 15:41:11  starvik
  28  *  Extracted v10 (ETRAX 100LX) specific stuff to arch/cris/arch-v10/kernel
  29  *
  30  *  Revision 1.11  2002/12/10 09:00:10  starvik
  31  *  Merge of Linux 2.5.51
  32  *
  33  *  Revision 1.10  2002/11/27 08:42:34  starvik
  34  *  Argument to user_regs() is thread_info*
  35  *
  36  *  Revision 1.9  2002/11/26 09:44:21  starvik
  37  *  New threads exits through ret_from_fork (necessary for preemptive scheduling)
  38  *
  39  *  Revision 1.8  2002/11/19 14:35:24  starvik
  40  *  Changes from linux 2.4
  41  *  Changed struct initializer syntax to the currently prefered notation
  42  *
  43  *  Revision 1.7  2002/11/18 07:39:42  starvik
  44  *  thread_saved_pc moved here from processor.h
  45  *
  46  *  Revision 1.6  2002/11/14 06:51:27  starvik
  47  *  Made cpu_idle more similar with other archs
  48  *  init_task_union -> init_thread_union
  49  *  Updated for new interrupt macros
  50  *  sys_clone and do_fork have a new argument, user_tid
  51  *
  52  *  Revision 1.5  2002/11/05 06:45:11  starvik
  53  *  Merge of Linux 2.5.45
  54  *
  55  *  Revision 1.4  2002/02/05 15:37:44  bjornw
  56  *  Need init_task.h
  57  *
  58  *  Revision 1.3  2002/01/21 15:22:49  bjornw
  59  *  current->counter is gone
  60  *
  61  *  Revision 1.22  2001/11/13 09:40:43  orjanf
  62  *  Added dump_fpu (needed for core dumps).
  63  *
  64  *  Revision 1.21  2001/11/12 18:26:21  pkj
  65  *  Fixed compiler warnings.
  66  *
  67  *  Revision 1.20  2001/10/03 08:21:39  jonashg
  68  *  cause_of_death does not exist if CONFIG_SVINTO_SIM is defined.
  69  *
  70  *  Revision 1.19  2001/09/26 11:52:54  bjornw
  71  *  INIT_MMAP is gone in 2.4.10
  72  *
  73  *  Revision 1.18  2001/08/21 21:43:51  hp
  74  *  Move last watchdog fix inside #ifdef CONFIG_ETRAX_WATCHDOG
  75  *
  76  *  Revision 1.17  2001/08/21 13:48:01  jonashg
  77  *  Added fix by HP to avoid oops when doing a hard_reset_now.
  78  *
  79  *  Revision 1.16  2001/06/21 02:00:40  hp
  80  *      * entry.S: Include asm/unistd.h.
  81  *      (_sys_call_table): Use section .rodata, not .data.
  82  *      (_kernel_thread): Move from...
  83  *      * process.c: ... here.
  84  *      * entryoffsets.c (VAL): Break out from...
  85  *      (OF): Use VAL.
  86  *      (LCLONE_VM): New asmified value from CLONE_VM.
  87  *
  88  *  Revision 1.15  2001/06/20 16:31:57  hp
  89  *  Add comments to describe empty functions according to review.
  90  *
  91  *  Revision 1.14  2001/05/29 11:27:59  markusl
  92  *  Fixed so that hard_reset_now will do reset even if watchdog wasn't enabled
  93  *
  94  *  Revision 1.13  2001/03/20 19:44:06  bjornw
  95  *  Use the 7th syscall argument for regs instead of current_regs
  96  *
  97  */
  98
  99 /*
 100  * This file handles the architecture-dependent parts of process handling..
 101  */
 102
 103 #include <asm/atomic.h>
 104 #include <asm/pgtable.h>
 105 #include <asm/uaccess.h>
 106 #include <asm/irq.h>
 107 #include <linux/module.h>
 108 #include <linux/spinlock.h>
 109 #include <linux/fs_struct.h>
 110 #include <linux/init_task.h>
 111 #include <linux/sched.h>
 112 #include <linux/fs.h>
 113 #include <linux/user.h>
 114 #include <linux/elfcore.h>
 115 #include <linux/mqueue.h>
 116
 117 //#define DEBUG
 118
 119 /*
 120  * Initial task structure. Make this a per-architecture thing,
 121  * because different architectures tend to have different
 122  * alignment requirements and potentially different initial
 123  * setup.
 124  */
 125
 126 static struct fs_struct init_fs = INIT_FS;
 127 static struct files_struct init_files = INIT_FILES;
 128 static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
 129 static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
 130 struct mm_struct init_mm = INIT_MM(init_mm);
 131
 132 EXPORT_SYMBOL(init_mm);
 133
 134 /*
 135  * Initial thread structure.
 136  *
 137  * We need to make sure that this is 8192-byte aligned due to the
 138  * way process stacks are handled. This is done by having a special
 139  * "init_task" linker map entry..
 140  */
 141 union thread_union init_thread_union
 142         __attribute__((__section__(".data.init_task"))) =
 143                 { INIT_THREAD_INFO(init_task) };
 144
 145 /*
 146  * Initial task structure.
 147  *
 148  * All other task structs will be allocated on slabs in fork.c
 149  */
 150 struct task_struct init_task = INIT_TASK(init_task);
 151
 152 EXPORT_SYMBOL(init_task);
 153
 154 /*
 155  * The hlt_counter, disable_hlt and enable_hlt is just here as a hook if
 156  * there would ever be a halt sequence (for power save when idle) with
 157  * some largish delay when halting or resuming *and* a driver that can't
 158  * afford that delay.  The hlt_counter would then be checked before
 159  * executing the halt sequence, and the driver marks the unhaltable
 160  * region by enable_hlt/disable_hlt.
 161  */
 162
 163 static int hlt_counter=0;
 164
 165 void disable_hlt(void)
 166 {
 167         hlt_counter++;
 168 }
 169
 170 EXPORT_SYMBOL(disable_hlt);
 171
 172 void enable_hlt(void)
 173 {
 174         hlt_counter--;
 175 }
 176
 177 EXPORT_SYMBOL(enable_hlt);
 178
 179 /*
 180  * The following aren't currently used.
 181  */
 182 void (*pm_idle)(void);
 183
 184 extern void default_idle(void);
 185
 186 /*
 187  * The idle thread. There's no useful work to be
 188  * done, so just try to conserve power and have a
 189  * low exit latency (ie sit in a loop waiting for
 190  * somebody to say that they'd like to reschedule)
 191  */
 192 void cpu_idle (void)
 193 {
 194         /* endless idle loop with no priority at all */
 195         while (1) {
 196                 while (!need_resched()) {
 197                         void (*idle)(void) = pm_idle;
 198
 199                         if (!idle)
 200                                 idle = default_idle;
 201
 202                         idle();
 203                 }
 204                 schedule();
 205         }
 206
 207 }
 208
 209 void hard_reset_now (void);
 210
 211 void machine_restart(void)
 212 {
 213         hard_reset_now();
 214 }
 215
 216 EXPORT_SYMBOL(machine_restart);
 217
 218 /*
 219  * Similar to machine_power_off, but don't shut off power.  Add code
 220  * here to freeze the system for e.g. post-mortem debug purpose when
 221  * possible.  This halt has nothing to do with the idle halt.
 222  */
 223
 224 void machine_halt(void)
 225 {
 226 }
 227
 228 EXPORT_SYMBOL(machine_halt);
 229
 230 /* If or when software power-off is implemented, add code here.  */
 231
 232 void machine_power_off(void)
 233 {
 234 }
 235
 236 EXPORT_SYMBOL(machine_power_off);
 237
 238 /*
 239  * When a process does an "exec", machine state like FPU and debug
 240  * registers need to be reset.  This is a hook function for that.
 241  * Currently we don't have any such state to reset, so this is empty.
 242  */
 243
 244 void flush_thread(void)
 245 {
 246 }
 247
 248 /*
 249  * fill in the user structure for a core dump..
 250  */
 251 void dump_thread(struct pt_regs * regs, struct user * dump)
 252 {
 253 #if 0
 254         int i;
 255
 256         /* changed the size calculations - should hopefully work better. lbt */
 257         dump->magic = CMAGIC;
 258         dump->start_code = 0;
 259         dump->start_stack = regs->esp & ~(PAGE_SIZE - 1);
 260         dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT;
 261         dump->u_dsize = ((unsigned long) (current->mm->brk + (PAGE_SIZE-1))) >> PAGE_SHIFT;
 262         dump->u_dsize -= dump->u_tsize;
 263         dump->u_ssize = 0;
 264         for (i = 0; i < 8; i++)
 265                 dump->u_debugreg[i] = current->debugreg[i];
 266
 267         if (dump->start_stack < TASK_SIZE)
 268                 dump->u_ssize = ((unsigned long) (TASK_SIZE - dump->start_stack)) >> PAGE_SHIFT;
 269
 270         dump->regs = *regs;
 271
 272         dump->u_fpvalid = dump_fpu (regs, &dump->i387);
 273 #endif
 274 }
 275
 276 /* Fill in the fpu structure for a core dump. */
 277 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 278 {
 279         return 0;
 280 }