tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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/*
23 * low level task data that entry.S needs immediate access to
24 * - this struct should fit entirely inside of one cache line
25 * - this struct shares the supervisor stack pages
26 * - if the contents of this structure are changed, the assembly constants must also be changed
27 */
28#ifndef __ASSEMBLY__
29
30struct thread_info {
31 struct task_struct *task; /* main task structure */
32 struct exec_domain *exec_domain; /* execution domain */
33 unsigned long flags; /* low level flags */
34 unsigned long status; /* thread-synchronous flags */
35 __u32 cpu; /* current CPU */
36 int preempt_count; /* 0 => preemptable, <0 => BUG */
37
38 mm_segment_t addr_limit; /* thread address space:
39 0-0xBFFFFFFF for user-thead
40 0-0xFFFFFFFF for kernel-thread
41 */
42 struct restart_block restart_block;
43
44 __u8 supervisor_stack[0];
45};
46
47#else /* !__ASSEMBLY__ */
48
49/* offsets into the thread_info struct for assembly code access */
50#define TI_TASK 0x00000000
51#define TI_EXEC_DOMAIN 0x00000004
52#define TI_FLAGS 0x00000008
53#define TI_STATUS 0x0000000C
54#define TI_CPU 0x00000010
55#define TI_PRE_COUNT 0x00000014
56#define TI_ADDR_LIMIT 0x00000018
57#define TI_RESTART_BLOCK 0x0000001C
58
59#endif
60
61#define PREEMPT_ACTIVE 0x10000000
62
63/*
64 * macros/functions for gaining access to the thread information structure
65 *
66 * preempt_count needs to be 1 initially, until the scheduler is functional.
67 */
68#ifndef __ASSEMBLY__
69
70#define INIT_THREAD_INFO(tsk) \
71{ \
72 .task = &tsk, \
73 .exec_domain = &default_exec_domain, \
74 .flags = 0, \
75 .cpu = 0, \
76 .preempt_count = 1, \
77 .addr_limit = KERNEL_DS, \
78 .restart_block = { \
79 .fn = do_no_restart_syscall, \
80 }, \
81}
82
83#define init_thread_info (init_thread_union.thread_info)
84#define init_stack (init_thread_union.stack)
85
86#ifdef CONFIG_SMALL_TASKS
87#define THREAD_SIZE 4096
88#else
89#define THREAD_SIZE 8192
90#endif
91
92/* how to get the thread information struct from C */
93register struct thread_info *__current_thread_info asm("gr15");
94
95#define current_thread_info() ({ __current_thread_info; })
96
97/* thread information allocation */
98#ifdef CONFIG_DEBUG_STACK_USAGE
99#define alloc_thread_info(tsk) \
100 ({ \
101 struct thread_info *ret; \
102 \
103 ret = kmalloc(THREAD_SIZE, GFP_KERNEL); \
104 if (ret) \
105 memset(ret, 0, THREAD_SIZE); \
106 ret; \
107 })
108#else
109#define alloc_thread_info(tsk) kmalloc(THREAD_SIZE, GFP_KERNEL)
110#endif
111
112#define free_thread_info(info) kfree(info)
113
114#else /* !__ASSEMBLY__ */
115
116#define THREAD_SIZE 8192
117
118#endif
119
120/*
121 * thread information flags
122 * - these are process state flags that various assembly files may need to access
123 * - pending work-to-be-done flags are in LSW
124 * - other flags in MSW
125 */
126#define TIF_SYSCALL_TRACE 0 /* syscall trace active */
127#define TIF_NOTIFY_RESUME 1 /* resumption notification requested */
128#define TIF_SIGPENDING 2 /* signal pending */
129#define TIF_NEED_RESCHED 3 /* rescheduling necessary */
130#define TIF_SINGLESTEP 4 /* restore singlestep on return to user mode */
131#define TIF_IRET 5 /* return with iret */
132#define TIF_POLLING_NRFLAG 16 /* true if poll_idle() is polling TIF_NEED_RESCHED */
133#define TIF_MEMDIE 17 /* OOM killer killed process */
134
135#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
136#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
137#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
138#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
139#define _TIF_SINGLESTEP (1 << TIF_SINGLESTEP)
140#define _TIF_IRET (1 << TIF_IRET)
141#define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG)
142
143#define _TIF_WORK_MASK 0x0000FFFE /* work to do on interrupt/exception return */
144#define _TIF_ALLWORK_MASK 0x0000FFFF /* work to do on any return to u-space */
145
146/*
147 * Thread-synchronous status.
148 *
149 * This is different from the flags in that nobody else
150 * ever touches our thread-synchronous status, so we don't
151 * have to worry about atomic accesses.
152 */
153#define TS_USEDFPM 0x0001 /* FPU/Media was used by this task this quantum (SMP) */
154
155#endif /* __KERNEL__ */
156
157#endif /* _ASM_THREAD_INFO_H */