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