[PATCH] UML Support - Ptrace: adds the host SYSEMU support, for UML and general usage
[linux-2.6.git] / include / asm-i386 / thread_info.h
1 /* 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
12 #include <linux/config.h>
13 #include <linux/compiler.h>
14 #include <asm/page.h>
15
16 #ifndef __ASSEMBLY__
17 #include <asm/processor.h>
18 #endif
19
20 /*
21  * low level task data that entry.S needs immediate access to
22  * - this struct should fit entirely inside of one cache line
23  * - this struct shares the supervisor stack pages
24  * - if the contents of this structure are changed, the assembly constants must also be changed
25  */
26 #ifndef __ASSEMBLY__
27
28 struct thread_info {
29         struct task_struct      *task;          /* main task structure */
30         struct exec_domain      *exec_domain;   /* execution domain */
31         unsigned long           flags;          /* low level flags */
32         unsigned long           status;         /* thread-synchronous flags */
33         __u32                   cpu;            /* current CPU */
34         int                     preempt_count;  /* 0 => preemptable, <0 => BUG */
35
36
37         mm_segment_t            addr_limit;     /* thread address space:
38                                                    0-0xBFFFFFFF for user-thead
39                                                    0-0xFFFFFFFF for kernel-thread
40                                                 */
41         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
51 #include <asm/asm_offsets.h>
52
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
87 /* how to get the thread information struct from C */
88 static inline struct thread_info *current_thread_info(void)
89 {
90         struct thread_info *ti;
91         __asm__("andl %%esp,%0; ":"=r" (ti) : "0" (~(THREAD_SIZE - 1)));
92         return ti;
93 }
94
95 /* how to get the current stack pointer from C */
96 register unsigned long current_stack_pointer asm("esp") __attribute_used__;
97
98 /* thread information allocation */
99 #ifdef CONFIG_DEBUG_STACK_USAGE
100 #define alloc_thread_info(tsk)                                  \
101         ({                                                      \
102                 struct thread_info *ret;                        \
103                                                                 \
104                 ret = kmalloc(THREAD_SIZE, GFP_KERNEL);         \
105                 if (ret)                                        \
106                         memset(ret, 0, THREAD_SIZE);            \
107                 ret;                                            \
108         })
109 #else
110 #define alloc_thread_info(tsk) kmalloc(THREAD_SIZE, GFP_KERNEL)
111 #endif
112
113 #define free_thread_info(info)  kfree(info)
114 #define get_thread_info(ti) get_task_struct((ti)->task)
115 #define put_thread_info(ti) put_task_struct((ti)->task)
116
117 #else /* !__ASSEMBLY__ */
118
119 /* how to get the thread information struct from ASM */
120 #define GET_THREAD_INFO(reg) \
121         movl $-THREAD_SIZE, reg; \
122         andl %esp, reg
123
124 /* use this one if reg already contains %esp */
125 #define GET_THREAD_INFO_WITH_ESP(reg) \
126         andl $-THREAD_SIZE, reg
127
128 #endif
129
130 /*
131  * thread information flags
132  * - these are process state flags that various assembly files may need to access
133  * - pending work-to-be-done flags are in LSW
134  * - other flags in MSW
135  */
136 #define TIF_SYSCALL_TRACE       0       /* syscall trace active */
137 #define TIF_NOTIFY_RESUME       1       /* resumption notification requested */
138 #define TIF_SIGPENDING          2       /* signal pending */
139 #define TIF_NEED_RESCHED        3       /* rescheduling necessary */
140 #define TIF_SINGLESTEP          4       /* restore singlestep on return to user mode */
141 #define TIF_IRET                5       /* return with iret */
142 #define TIF_SYSCALL_EMU         6       /* syscall emulation active */
143 #define TIF_SYSCALL_AUDIT       7       /* syscall auditing active */
144 #define TIF_SECCOMP             8       /* secure computing */
145 #define TIF_POLLING_NRFLAG      16      /* true if poll_idle() is polling TIF_NEED_RESCHED */
146 #define TIF_MEMDIE              17
147
148 #define _TIF_SYSCALL_TRACE      (1<<TIF_SYSCALL_TRACE)
149 #define _TIF_NOTIFY_RESUME      (1<<TIF_NOTIFY_RESUME)
150 #define _TIF_SIGPENDING         (1<<TIF_SIGPENDING)
151 #define _TIF_NEED_RESCHED       (1<<TIF_NEED_RESCHED)
152 #define _TIF_SINGLESTEP         (1<<TIF_SINGLESTEP)
153 #define _TIF_IRET               (1<<TIF_IRET)
154 #define _TIF_SYSCALL_EMU        (1<<TIF_SYSCALL_EMU)
155 #define _TIF_SYSCALL_AUDIT      (1<<TIF_SYSCALL_AUDIT)
156 #define _TIF_SECCOMP            (1<<TIF_SECCOMP)
157 #define _TIF_POLLING_NRFLAG     (1<<TIF_POLLING_NRFLAG)
158
159 /* work to do on interrupt/exception return */
160 #define _TIF_WORK_MASK \
161   (0x0000FFFF & ~(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP|\
162                   _TIF_SECCOMP|_TIF_SYSCALL_EMU))
163 /* work to do on any return to u-space */
164 #define _TIF_ALLWORK_MASK       (0x0000FFFF & ~_TIF_SECCOMP)
165
166 /*
167  * Thread-synchronous status.
168  *
169  * This is different from the flags in that nobody else
170  * ever touches our thread-synchronous status, so we don't
171  * have to worry about atomic accesses.
172  */
173 #define TS_USEDFPU              0x0001  /* FPU was used by this task this quantum (SMP) */
174
175 #endif /* __KERNEL__ */
176
177 #endif /* _ASM_THREAD_INFO_H */