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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* thread_info.h: i386 low-level thread information
2 *
3 * Copyright (C) 2002 David Howells (dhowells@redhat.com)
4 * - Incorporating suggestions made by Linus Torvalds and Dave Miller
5 */
6
7#ifndef _ASM_THREAD_INFO_H
8#define _ASM_THREAD_INFO_H
9
10#ifdef __KERNEL__
11
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <linux/compiler.h>
13#include <asm/page.h>
14
15#ifndef __ASSEMBLY__
16#include <asm/processor.h>
17#endif
18
19/*
20 * low level task data that entry.S needs immediate access to
21 * - this struct should fit entirely inside of one cache line
22 * - this struct shares the supervisor stack pages
23 * - if the contents of this structure are changed, the assembly constants must also be changed
24 */
25#ifndef __ASSEMBLY__
26
27struct thread_info {
28 struct task_struct *task; /* main task structure */
29 struct exec_domain *exec_domain; /* execution domain */
30 unsigned long flags; /* low level flags */
31 unsigned long status; /* thread-synchronous flags */
32 __u32 cpu; /* current CPU */
Jesper Juhldcd497f2005-06-23 00:09:07 -070033 int preempt_count; /* 0 => preemptable, <0 => BUG */
Linus Torvalds1da177e2005-04-16 15:20:36 -070034
35
36 mm_segment_t addr_limit; /* thread address space:
37 0-0xBFFFFFFF for user-thead
38 0-0xFFFFFFFF for kernel-thread
39 */
Ingo Molnare6e54942006-06-27 02:53:50 -070040 void *sysenter_return;
Linus Torvalds1da177e2005-04-16 15:20:36 -070041 struct restart_block restart_block;
42
43 unsigned long previous_esp; /* ESP of the previous stack in case
44 of nested (IRQ) stacks
45 */
46 __u8 supervisor_stack[0];
47};
48
49#else /* !__ASSEMBLY__ */
50
Sam Ravnborg86feeaa2005-09-09 19:28:28 +020051#include <asm/asm-offsets.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070052
53#endif
54
55#define PREEMPT_ACTIVE 0x10000000
56#ifdef CONFIG_4KSTACKS
57#define THREAD_SIZE (4096)
58#else
59#define THREAD_SIZE (8192)
60#endif
61
62#define STACK_WARN (THREAD_SIZE/8)
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
Chuck Ebbertc723e0842006-06-27 02:53:47 -070087/* how to get the current stack pointer from C */
88register unsigned long current_stack_pointer asm("esp") __attribute_used__;
89
Linus Torvalds1da177e2005-04-16 15:20:36 -070090/* how to get the thread information struct from C */
91static inline struct thread_info *current_thread_info(void)
92{
Chuck Ebbertc723e0842006-06-27 02:53:47 -070093 return (struct thread_info *)(current_stack_pointer & ~(THREAD_SIZE - 1));
Linus Torvalds1da177e2005-04-16 15:20:36 -070094}
95
Linus Torvalds1da177e2005-04-16 15:20:36 -070096/* thread information allocation */
97#ifdef CONFIG_DEBUG_STACK_USAGE
98#define alloc_thread_info(tsk) \
99 ({ \
100 struct thread_info *ret; \
101 \
102 ret = kmalloc(THREAD_SIZE, GFP_KERNEL); \
103 if (ret) \
104 memset(ret, 0, THREAD_SIZE); \
105 ret; \
106 })
107#else
108#define alloc_thread_info(tsk) kmalloc(THREAD_SIZE, GFP_KERNEL)
109#endif
110
111#define free_thread_info(info) kfree(info)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112
113#else /* !__ASSEMBLY__ */
114
115/* how to get the thread information struct from ASM */
116#define GET_THREAD_INFO(reg) \
117 movl $-THREAD_SIZE, reg; \
118 andl %esp, reg
119
120/* use this one if reg already contains %esp */
121#define GET_THREAD_INFO_WITH_ESP(reg) \
122 andl $-THREAD_SIZE, reg
123
124#endif
125
126/*
127 * thread information flags
128 * - these are process state flags that various assembly files may need to access
129 * - pending work-to-be-done flags are in LSW
130 * - other flags in MSW
131 */
132#define TIF_SYSCALL_TRACE 0 /* syscall trace active */
133#define TIF_NOTIFY_RESUME 1 /* resumption notification requested */
134#define TIF_SIGPENDING 2 /* signal pending */
135#define TIF_NEED_RESCHED 3 /* rescheduling necessary */
136#define TIF_SINGLESTEP 4 /* restore singlestep on return to user mode */
137#define TIF_IRET 5 /* return with iret */
Laurent Viviered75e8d2005-09-03 15:57:18 -0700138#define TIF_SYSCALL_EMU 6 /* syscall emulation active */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139#define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */
140#define TIF_SECCOMP 8 /* secure computing */
David Howells283828f2006-01-18 17:44:00 -0800141#define TIF_RESTORE_SIGMASK 9 /* restore signal mask in do_signal() */
Andi Kleen495ab9c2006-06-26 13:59:11 +0200142#define TIF_MEMDIE 16
Stephane Eranianb3cf2572006-07-09 21:12:39 -0400143#define TIF_DEBUG 17 /* uses debug registers */
144#define TIF_IO_BITMAP 18 /* uses I/O bitmap */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145
146#define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
147#define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME)
148#define _TIF_SIGPENDING (1<<TIF_SIGPENDING)
149#define _TIF_NEED_RESCHED (1<<TIF_NEED_RESCHED)
150#define _TIF_SINGLESTEP (1<<TIF_SINGLESTEP)
151#define _TIF_IRET (1<<TIF_IRET)
Laurent Viviered75e8d2005-09-03 15:57:18 -0700152#define _TIF_SYSCALL_EMU (1<<TIF_SYSCALL_EMU)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153#define _TIF_SYSCALL_AUDIT (1<<TIF_SYSCALL_AUDIT)
154#define _TIF_SECCOMP (1<<TIF_SECCOMP)
David Howells283828f2006-01-18 17:44:00 -0800155#define _TIF_RESTORE_SIGMASK (1<<TIF_RESTORE_SIGMASK)
Stephane Eranianb3cf2572006-07-09 21:12:39 -0400156#define _TIF_DEBUG (1<<TIF_DEBUG)
157#define _TIF_IO_BITMAP (1<<TIF_IO_BITMAP)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158
159/* work to do on interrupt/exception return */
160#define _TIF_WORK_MASK \
Chuck Ebbertcfe91f92006-02-17 03:16:55 -0500161 (0x0000FFFF & ~(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
162 _TIF_SECCOMP | _TIF_SYSCALL_EMU))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163/* work to do on any return to u-space */
164#define _TIF_ALLWORK_MASK (0x0000FFFF & ~_TIF_SECCOMP)
165
Stephane Eranianb3cf2572006-07-09 21:12:39 -0400166/* flags to check in __switch_to() */
167#define _TIF_WORK_CTXSW (_TIF_DEBUG|_TIF_IO_BITMAP)
168
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169/*
170 * Thread-synchronous status.
171 *
172 * This is different from the flags in that nobody else
173 * ever touches our thread-synchronous status, so we don't
174 * have to worry about atomic accesses.
175 */
176#define TS_USEDFPU 0x0001 /* FPU was used by this task this quantum (SMP) */
Andi Kleen495ab9c2006-06-26 13:59:11 +0200177#define TS_POLLING 0x0002 /* True if in idle loop and not sleeping */
178
179#define tsk_is_polling(t) ((t)->thread_info->status & TS_POLLING)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180
181#endif /* __KERNEL__ */
182
183#endif /* _ASM_THREAD_INFO_H */