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Linux kernel mirror (for testing)
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linux
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/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,
24 * the assembly constants must also be changed
25 */
26#ifndef __ASSEMBLY__
27
28struct 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,
35 <0 => BUG */
36 mm_segment_t addr_limit; /* thread address space:
37 0-0xBFFFFFFF user-thread
38 0-0xFFFFFFFF kernel-thread
39 */
40 void *sysenter_return;
41 struct restart_block restart_block;
42 unsigned long previous_esp; /* ESP of the previous stack in
43 case of nested (IRQ) stacks
44 */
45 __u8 supervisor_stack[0];
46};
47
48#else /* !__ASSEMBLY__ */
49
50#include <asm/asm-offsets.h>
51
52#endif
53
54#define PREEMPT_ACTIVE 0x10000000
55#ifdef CONFIG_4KSTACKS
56#define THREAD_SIZE (4096)
57#else
58#define THREAD_SIZE (8192)
59#endif
60
61#define STACK_WARN (THREAD_SIZE/8)
62/*
63 * macros/functions for gaining access to the thread information structure
64 *
65 * preempt_count needs to be 1 initially, until the scheduler is functional.
66 */
67#ifndef __ASSEMBLY__
68
69#define INIT_THREAD_INFO(tsk) \
70{ \
71 .task = &tsk, \
72 .exec_domain = &default_exec_domain, \
73 .flags = 0, \
74 .cpu = 0, \
75 .preempt_count = 1, \
76 .addr_limit = KERNEL_DS, \
77 .restart_block = { \
78 .fn = do_no_restart_syscall, \
79 }, \
80}
81
82#define init_thread_info (init_thread_union.thread_info)
83#define init_stack (init_thread_union.stack)
84
85
86/* how to get the current stack pointer from C */
87register unsigned long current_stack_pointer asm("esp") __used;
88
89/* how to get the thread information struct from C */
90static inline struct thread_info *current_thread_info(void)
91{
92 return (struct thread_info *)
93 (current_stack_pointer & ~(THREAD_SIZE - 1));
94}
95
96/* thread information allocation */
97#ifdef CONFIG_DEBUG_STACK_USAGE
98#define alloc_thread_info(tsk) ((struct thread_info *) \
99 __get_free_pages(GFP_KERNEL | __GFP_ZERO, get_order(THREAD_SIZE)))
100#else
101#define alloc_thread_info(tsk) ((struct thread_info *) \
102 __get_free_pages(GFP_KERNEL, get_order(THREAD_SIZE)))
103#endif
104
105#else /* !__ASSEMBLY__ */
106
107/* how to get the thread information struct from ASM */
108#define GET_THREAD_INFO(reg) \
109 movl $-THREAD_SIZE, reg; \
110 andl %esp, reg
111
112/* use this one if reg already contains %esp */
113#define GET_THREAD_INFO_WITH_ESP(reg) \
114 andl $-THREAD_SIZE, reg
115
116#endif
117
118/*
119 * thread information flags
120 * - these are process state flags that various
121 * assembly files may need to access
122 * - pending work-to-be-done flags are in LSW
123 * - other flags in MSW
124 */
125#define TIF_SYSCALL_TRACE 0 /* syscall trace active */
126#define TIF_SIGPENDING 1 /* signal pending */
127#define TIF_NEED_RESCHED 2 /* rescheduling necessary */
128#define TIF_SINGLESTEP 3 /* restore singlestep on return to
129 user mode */
130#define TIF_IRET 4 /* return with iret */
131#define TIF_SYSCALL_EMU 5 /* syscall emulation active */
132#define TIF_SYSCALL_AUDIT 6 /* syscall auditing active */
133#define TIF_SECCOMP 7 /* secure computing */
134#define TIF_HRTICK_RESCHED 9 /* reprogram hrtick timer */
135#define TIF_MEMDIE 16
136#define TIF_DEBUG 17 /* uses debug registers */
137#define TIF_IO_BITMAP 18 /* uses I/O bitmap */
138#define TIF_FREEZE 19 /* is freezing for suspend */
139#define TIF_NOTSC 20 /* TSC is not accessible in userland */
140#define TIF_FORCED_TF 21 /* true if TF in eflags artificially */
141#define TIF_DEBUGCTLMSR 22 /* uses thread_struct.debugctlmsr */
142#define TIF_DS_AREA_MSR 23 /* uses thread_struct.ds_area_msr */
143#define TIF_BTS_TRACE_TS 24 /* record scheduling event timestamps */
144
145#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
146#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
147#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
148#define _TIF_SINGLESTEP (1 << TIF_SINGLESTEP)
149#define _TIF_IRET (1 << TIF_IRET)
150#define _TIF_SYSCALL_EMU (1 << TIF_SYSCALL_EMU)
151#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
152#define _TIF_SECCOMP (1 << TIF_SECCOMP)
153#define _TIF_HRTICK_RESCHED (1 << TIF_HRTICK_RESCHED)
154#define _TIF_DEBUG (1 << TIF_DEBUG)
155#define _TIF_IO_BITMAP (1 << TIF_IO_BITMAP)
156#define _TIF_FREEZE (1 << TIF_FREEZE)
157#define _TIF_NOTSC (1 << TIF_NOTSC)
158#define _TIF_FORCED_TF (1 << TIF_FORCED_TF)
159#define _TIF_DEBUGCTLMSR (1 << TIF_DEBUGCTLMSR)
160#define _TIF_DS_AREA_MSR (1 << TIF_DS_AREA_MSR)
161#define _TIF_BTS_TRACE_TS (1 << TIF_BTS_TRACE_TS)
162
163/* work to do on interrupt/exception return */
164#define _TIF_WORK_MASK \
165 (0x0000FFFF & ~(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
166 _TIF_SECCOMP | _TIF_SYSCALL_EMU))
167/* work to do on any return to u-space */
168#define _TIF_ALLWORK_MASK (0x0000FFFF & ~_TIF_SECCOMP)
169
170/* flags to check in __switch_to() */
171#define _TIF_WORK_CTXSW \
172 (_TIF_IO_BITMAP | _TIF_NOTSC | _TIF_DEBUGCTLMSR | \
173 _TIF_DS_AREA_MSR | _TIF_BTS_TRACE_TS)
174#define _TIF_WORK_CTXSW_PREV _TIF_WORK_CTXSW
175#define _TIF_WORK_CTXSW_NEXT (_TIF_WORK_CTXSW | _TIF_DEBUG)
176
177
178/*
179 * Thread-synchronous status.
180 *
181 * This is different from the flags in that nobody else
182 * ever touches our thread-synchronous status, so we don't
183 * have to worry about atomic accesses.
184 */
185#define TS_USEDFPU 0x0001 /* FPU was used by this task
186 this quantum (SMP) */
187#define TS_POLLING 0x0002 /* True if in idle loop
188 and not sleeping */
189#define TS_RESTORE_SIGMASK 0x0004 /* restore signal mask in do_signal() */
190
191#define tsk_is_polling(t) (task_thread_info(t)->status & TS_POLLING)
192
193#ifndef __ASSEMBLY__
194#define HAVE_SET_RESTORE_SIGMASK 1
195static inline void set_restore_sigmask(void)
196{
197 struct thread_info *ti = current_thread_info();
198 ti->status |= TS_RESTORE_SIGMASK;
199 set_bit(TIF_SIGPENDING, &ti->flags);
200}
201#endif /* !__ASSEMBLY__ */
202
203#endif /* __KERNEL__ */
204
205#endif /* _ASM_THREAD_INFO_H */