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
12 #include <linux/config.h>
16 #include <asm/processor.h>
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
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 */
33 __s32 preempt_count; /* 0 => preemptable, <0 => BUG */
36 mm_segment_t addr_limit; /* thread address space:
37 0-0xBFFFFFFF for user-thead
38 0-0xFFFFFFFF for kernel-thread
40 struct restart_block restart_block;
42 unsigned long previous_esp; /* ESP of the previous stack in case
43 of nested (IRQ) stacks
45 __u8 supervisor_stack[0];
48 #else /* !__ASSEMBLY__ */
50 /* offsets into the thread_info struct for assembly code access */
51 #define TI_TASK 0x00000000
52 #define TI_EXEC_DOMAIN 0x00000004
53 #define TI_FLAGS 0x00000008
54 #define TI_STATUS 0x0000000C
55 #define TI_CPU 0x00000010
56 #define TI_PRE_COUNT 0x00000014
57 #define TI_ADDR_LIMIT 0x00000018
58 #define TI_RESTART_BLOCK 0x000001C
62 #define PREEMPT_ACTIVE 0x4000000
63 #ifdef CONFIG_4KSTACKS
64 #define THREAD_SIZE (4096)
66 #define THREAD_SIZE (8192)
69 #define STACK_WARN (THREAD_SIZE/8)
71 * macros/functions for gaining access to the thread information structure
73 * preempt_count needs to be 1 initially, until the scheduler is functional.
77 #define INIT_THREAD_INFO(tsk) \
80 .exec_domain = &default_exec_domain, \
84 .addr_limit = KERNEL_DS, \
86 .fn = do_no_restart_syscall, \
90 #define init_thread_info (init_thread_union.thread_info)
91 #define init_stack (init_thread_union.stack)
94 /* how to get the thread information struct from C */
95 static inline struct thread_info *current_thread_info(void)
97 struct thread_info *ti;
98 __asm__("andl %%esp,%0; ":"=r" (ti) : "0" (~(THREAD_SIZE - 1)));
102 /* how to get the current stack pointer from C */
103 static inline unsigned long current_stack_pointer(void)
106 __asm__("movl %%esp,%0; ":"=r" (ti) : );
110 /* thread information allocation */
111 #ifdef CONFIG_DEBUG_STACK_USAGE
112 #define alloc_thread_info(tsk) \
114 struct thread_info *ret; \
116 ret = kmalloc(THREAD_SIZE, GFP_KERNEL); \
118 memset(ret, 0, THREAD_SIZE); \
122 #define alloc_thread_info(tsk) kmalloc(THREAD_SIZE, GFP_KERNEL)
125 #define free_thread_info(info) kfree(info)
126 #define get_thread_info(ti) get_task_struct((ti)->task)
127 #define put_thread_info(ti) put_task_struct((ti)->task)
129 #else /* !__ASSEMBLY__ */
131 /* how to get the thread information struct from ASM */
132 #define GET_THREAD_INFO(reg) \
133 movl $-THREAD_SIZE, reg; \
136 /* use this one if reg already contains %esp */
137 #define GET_THREAD_INFO_WITH_ESP(reg) \
138 andl $-THREAD_SIZE, reg
143 * thread information flags
144 * - these are process state flags that various assembly files may need to access
145 * - pending work-to-be-done flags are in LSW
146 * - other flags in MSW
148 #define TIF_SYSCALL_TRACE 0 /* syscall trace active */
149 #define TIF_NOTIFY_RESUME 1 /* resumption notification requested */
150 #define TIF_SIGPENDING 2 /* signal pending */
151 #define TIF_NEED_RESCHED 3 /* rescheduling necessary */
152 #define TIF_SINGLESTEP 4 /* restore singlestep on return to user mode */
153 #define TIF_IRET 5 /* return with iret */
154 #define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */
155 #define TIF_POLLING_NRFLAG 16 /* true if poll_idle() is polling TIF_NEED_RESCHED */
157 #define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
158 #define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME)
159 #define _TIF_SIGPENDING (1<<TIF_SIGPENDING)
160 #define _TIF_NEED_RESCHED (1<<TIF_NEED_RESCHED)
161 #define _TIF_SINGLESTEP (1<<TIF_SINGLESTEP)
162 #define _TIF_IRET (1<<TIF_IRET)
163 #define _TIF_SYSCALL_AUDIT (1<<TIF_SYSCALL_AUDIT)
164 #define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
166 /* work to do on interrupt/exception return */
167 #define _TIF_WORK_MASK \
168 (0x0000FFFF & ~(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT))
169 #define _TIF_ALLWORK_MASK 0x0000FFFF /* work to do on any return to u-space */
172 * Thread-synchronous status.
174 * This is different from the flags in that nobody else
175 * ever touches our thread-synchronous status, so we don't
176 * have to worry about atomic accesses.
178 #define TS_USEDFPU 0x0001 /* FPU was used by this task this quantum (SMP) */
180 #endif /* __KERNEL__ */
182 #endif /* _ASM_THREAD_INFO_H */