1 /* thread_info.h: i386 low-level thread information
3 * Copyright (C) 2002 David Howells (dhowells@redhat.com)
4 * - Incorporating suggestions made by Linus Torvalds and Dave Miller
7 #ifndef _ASM_THREAD_INFO_H
8 #define _ASM_THREAD_INFO_H
13 #include <asm/processor.h>
17 * low level task data that entry.S needs immediate access to
18 * - this struct should fit entirely inside of one cache line
19 * - this struct shares the supervisor stack pages
20 * - if the contents of this structure are changed, the assembly constants must also be changed
25 struct task_struct *task; /* main task structure */
26 struct exec_domain *exec_domain; /* execution domain */
27 unsigned long flags; /* low level flags */
28 unsigned long status; /* thread-synchronous flags */
29 __u32 cpu; /* current CPU */
30 __s32 preempt_count; /* 0 => preemptable, <0 => BUG */
32 mm_segment_t addr_limit; /* thread address space:
33 0-0xBFFFFFFF for user-thead
34 0-0xFFFFFFFF for kernel-thread
36 struct restart_block restart_block;
38 __u8 supervisor_stack[0];
41 #else /* !__ASSEMBLY__ */
43 /* offsets into the thread_info struct for assembly code access */
44 #define TI_TASK 0x00000000
45 #define TI_EXEC_DOMAIN 0x00000004
46 #define TI_FLAGS 0x00000008
47 #define TI_STATUS 0x0000000C
48 #define TI_CPU 0x00000010
49 #define TI_PRE_COUNT 0x00000014
50 #define TI_ADDR_LIMIT 0x00000018
51 #define TI_RESTART_BLOCK 0x000001C
55 #define PREEMPT_ACTIVE 0x4000000
58 * macros/functions for gaining access to the thread information structure
60 * preempt_count needs to be 1 initially, until the scheduler is functional.
64 #define INIT_THREAD_INFO(tsk) \
67 .exec_domain = &default_exec_domain, \
71 .addr_limit = KERNEL_DS, \
73 .fn = do_no_restart_syscall, \
77 #define init_thread_info (init_thread_union.thread_info)
78 #define init_stack (init_thread_union.stack)
80 /* how to get the thread information struct from C */
81 static inline struct thread_info *current_thread_info(void)
83 struct thread_info *ti;
85 __asm__ __volatile__ (
86 "ldi %0, #0xffffe000; \n\t"
94 /* thread information allocation */
95 #define THREAD_SIZE (2*PAGE_SIZE)
96 #define alloc_thread_info(task) \
97 ((struct thread_info *) __get_free_pages(GFP_KERNEL,1))
98 #define free_thread_info(ti) free_pages((unsigned long) (ti), 1)
99 #define get_thread_info(ti) get_task_struct((ti)->task)
100 #define put_thread_info(ti) put_task_struct((ti)->task)
102 #else /* !__ASSEMBLY__ */
104 /* how to get the thread information struct from ASM */
105 #define GET_THREAD_INFO(reg) GET_THREAD_INFO reg
106 .macro GET_THREAD_INFO reg
107 ldi \reg, #0xffffe000
114 * thread information flags
115 * - these are process state flags that various assembly files may need to access
116 * - pending work-to-be-done flags are in LSW
117 * - other flags in MSW
119 #define TIF_SYSCALL_TRACE 0 /* syscall trace active */
120 #define TIF_NOTIFY_RESUME 1 /* resumption notification requested */
121 #define TIF_SIGPENDING 2 /* signal pending */
122 #define TIF_NEED_RESCHED 3 /* rescheduling necessary */
123 #define TIF_SINGLESTEP 4 /* restore singlestep on return to user mode */
124 #define TIF_IRET 5 /* return with iret */
125 #define TIF_POLLING_NRFLAG 16 /* true if poll_idle() is polling TIF_NEED_RESCHED */
127 #define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
128 #define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME)
129 #define _TIF_SIGPENDING (1<<TIF_SIGPENDING)
130 #define _TIF_NEED_RESCHED (1<<TIF_NEED_RESCHED)
131 #define _TIF_SINGLESTEP (1<<TIF_SINGLESTEP)
132 #define _TIF_IRET (1<<TIF_IRET)
133 #define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
135 #define _TIF_WORK_MASK 0x0000FFFE /* work to do on interrupt/exception return */
136 #define _TIF_ALLWORK_MASK 0x0000FFFF /* work to do on any return to u-space */
139 * Thread-synchronous status.
141 * This is different from the flags in that nobody else
142 * ever touches our thread-synchronous status, so we don't
143 * have to worry about atomic accesses.
145 #define TS_USEDFPU 0x0001 /* FPU was used by this task this quantum (SMP) */
147 #endif /* __KERNEL__ */
149 #endif /* _ASM_THREAD_INFO_H */