1/* thread_info.h: description
2 *
3 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 * Derived from include/asm-i386/thread_info.h
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 */
12
13#ifndef _ASM_THREAD_INFO_H
14#define _ASM_THREAD_INFO_H
15
16#ifdef __KERNEL__
17
18#ifndef __ASSEMBLY__
19#include <asm/processor.h>
20#endif
21
22#define THREAD_SIZE		8192
23
24/*
25 * low level task data that entry.S needs immediate access to
26 * - this struct should fit entirely inside of one cache line
27 * - this struct shares the supervisor stack pages
28 * - if the contents of this structure are changed, the assembly constants must also be changed
29 */
30#ifndef __ASSEMBLY__
31
32struct thread_info {
33	struct task_struct	*task;		/* main task structure */
34	struct exec_domain	*exec_domain;	/* execution domain */
35	unsigned long		flags;		/* low level flags */
36	unsigned long		status;		/* thread-synchronous flags */
37	__u32			cpu;		/* current CPU */
38	int			preempt_count;	/* 0 => preemptable, <0 => BUG */
39
40	mm_segment_t		addr_limit;	/* thread address space:
41					 	   0-0xBFFFFFFF for user-thead
42						   0-0xFFFFFFFF for kernel-thread
43						*/
44	struct restart_block    restart_block;
45
46	__u8			supervisor_stack[0];
47};
48
49#else /* !__ASSEMBLY__ */
50
51#include <asm/asm-offsets.h>
52
53#endif
54
55#define PREEMPT_ACTIVE		0x10000000
56
57/*
58 * macros/functions for gaining access to the thread information structure
59 *
60 * preempt_count needs to be 1 initially, until the scheduler is functional.
61 */
62#ifndef __ASSEMBLY__
63
64#define INIT_THREAD_INFO(tsk)			\
65{						\
66	.task		= &tsk,			\
67	.exec_domain	= &default_exec_domain,	\
68	.flags		= 0,			\
69	.cpu		= 0,			\
70	.preempt_count	= 1,			\
71	.addr_limit	= KERNEL_DS,		\
72	.restart_block = {			\
73		.fn = do_no_restart_syscall,	\
74	},					\
75}
76
77#define init_thread_info	(init_thread_union.thread_info)
78#define init_stack		(init_thread_union.stack)
79
80/* how to get the thread information struct from C */
81register struct thread_info *__current_thread_info asm("gr15");
82
83#define current_thread_info() ({ __current_thread_info; })
84
85/* thread information allocation */
86#ifdef CONFIG_DEBUG_STACK_USAGE
87#define alloc_thread_info(tsk)					\
88	({							\
89		struct thread_info *ret;			\
90								\
91		ret = kmalloc(THREAD_SIZE, GFP_KERNEL);		\
92		if (ret)					\
93			memset(ret, 0, THREAD_SIZE);		\
94		ret;						\
95	})
96#else
97#define alloc_thread_info(tsk)	kmalloc(THREAD_SIZE, GFP_KERNEL)
98#endif
99
100#define free_thread_info(info)	kfree(info)
101
102#endif /* __ASSEMBLY__ */
103
104/*
105 * thread information flags
106 * - these are process state flags that various assembly files may need to access
107 * - pending work-to-be-done flags are in LSW
108 * - other flags in MSW
109 */
110#define TIF_SYSCALL_TRACE	0	/* syscall trace active */
111#define TIF_NOTIFY_RESUME	1	/* resumption notification requested */
112#define TIF_SIGPENDING		2	/* signal pending */
113#define TIF_NEED_RESCHED	3	/* rescheduling necessary */
114#define TIF_SINGLESTEP		4	/* restore singlestep on return to user mode */
115#define TIF_IRET		5	/* return with iret */
116#define TIF_RESTORE_SIGMASK	6	/* restore signal mask in do_signal() */
117#define TIF_POLLING_NRFLAG	16	/* true if poll_idle() is polling TIF_NEED_RESCHED */
118#define TIF_MEMDIE		17	/* OOM killer killed process */
119#define TIF_FREEZE		18	/* freezing for suspend */
120
121#define _TIF_SYSCALL_TRACE	(1 << TIF_SYSCALL_TRACE)
122#define _TIF_NOTIFY_RESUME	(1 << TIF_NOTIFY_RESUME)
123#define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)
124#define _TIF_NEED_RESCHED	(1 << TIF_NEED_RESCHED)
125#define _TIF_SINGLESTEP		(1 << TIF_SINGLESTEP)
126#define _TIF_IRET		(1 << TIF_IRET)
127#define _TIF_RESTORE_SIGMASK	(1 << TIF_RESTORE_SIGMASK)
128#define _TIF_POLLING_NRFLAG	(1 << TIF_POLLING_NRFLAG)
129#define _TIF_FREEZE		(1 << TIF_FREEZE)
130
131#define _TIF_WORK_MASK		0x0000FFFE	/* work to do on interrupt/exception return */
132#define _TIF_ALLWORK_MASK	0x0000FFFF	/* work to do on any return to u-space */
133
134/*
135 * Thread-synchronous status.
136 *
137 * This is different from the flags in that nobody else
138 * ever touches our thread-synchronous status, so we don't
139 * have to worry about atomic accesses.
140 */
141#define TS_USEDFPM		0x0001	/* FPU/Media was used by this task this quantum (SMP) */
142
143#endif /* __KERNEL__ */
144
145#endif /* _ASM_THREAD_INFO_H */
146