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	unsigned long		flags;		/* low level flags */
35	unsigned long		status;		/* thread-synchronous flags */
36	__u32			cpu;		/* current CPU */
37	int			preempt_count;	/* 0 => preemptable, <0 => BUG */
38
39	mm_segment_t		addr_limit;	/* thread address space:
40						 * 0-0xBFFFFFFF for user-thead
41						 * 0-0xFFFFFFFF for kernel-thread
42						 */
43
44	__u8			supervisor_stack[0];
45};
46
47#else /* !__ASSEMBLY__ */
48
49#include <asm/asm-offsets.h>
50
51#endif
52
53/*
54 * macros/functions for gaining access to the thread information structure
55 */
56#ifndef __ASSEMBLY__
57
58#define INIT_THREAD_INFO(tsk)			\
59{						\
60	.task		= &tsk,			\
61	.flags		= 0,			\
62	.cpu		= 0,			\
63	.preempt_count	= INIT_PREEMPT_COUNT,	\
64	.addr_limit	= KERNEL_DS,		\
65}
66
67#define init_thread_info	(init_thread_union.thread_info)
68#define init_stack		(init_thread_union.stack)
69
70/* how to get the thread information struct from C */
71register struct thread_info *__current_thread_info asm("gr15");
72
73#define current_thread_info() ({ __current_thread_info; })
74
75#endif /* __ASSEMBLY__ */
76
77/*
78 * thread information flags
79 * - these are process state flags that various assembly files may need to access
80 * - pending work-to-be-done flags are in LSW
81 * - other flags in MSW
82 */
83#define TIF_SYSCALL_TRACE	0	/* syscall trace active */
84#define TIF_NOTIFY_RESUME	1	/* callback before returning to user */
85#define TIF_SIGPENDING		2	/* signal pending */
86#define TIF_NEED_RESCHED	3	/* rescheduling necessary */
87#define TIF_SINGLESTEP		4	/* restore singlestep on return to user mode */
88#define TIF_RESTORE_SIGMASK	5	/* restore signal mask in do_signal() */
89#define TIF_MEMDIE		7	/* is terminating due to OOM killer */
90
91#define _TIF_SYSCALL_TRACE	(1 << TIF_SYSCALL_TRACE)
92#define _TIF_NOTIFY_RESUME	(1 << TIF_NOTIFY_RESUME)
93#define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)
94#define _TIF_NEED_RESCHED	(1 << TIF_NEED_RESCHED)
95#define _TIF_SINGLESTEP		(1 << TIF_SINGLESTEP)
96
97/* work to do on interrupt/exception return */
98#define _TIF_WORK_MASK		\
99	(_TIF_NOTIFY_RESUME | _TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_SINGLESTEP)
100
101/* work to do on any return to u-space */
102#define _TIF_ALLWORK_MASK	(_TIF_WORK_MASK | _TIF_SYSCALL_TRACE)
103
104#if _TIF_ALLWORK_MASK >= 0x2000
105#error "_TIF_ALLWORK_MASK won't fit in an ANDI now (see entry.S)"
106#endif
107
108/*
109 * Thread-synchronous status.
110 *
111 * This is different from the flags in that nobody else
112 * ever touches our thread-synchronous status, so we don't
113 * have to worry about atomic accesses.
114 */
115#define TS_USEDFPM		0x0001	/* FPU/Media was used by this task this quantum (SMP) */
116
117#endif /* __KERNEL__ */
118
119#endif /* _ASM_THREAD_INFO_H */
120