1/* thread_info.h: x86_64 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 <asm/page.h>
13#include <asm/types.h>
14#include <asm/pda.h>
15
16/*
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 */
21#ifndef __ASSEMBLY__
22struct task_struct;
23struct exec_domain;
24#include <asm/mmsegment.h>
25
26struct thread_info {
27	struct task_struct	*task;		/* main task structure */
28	struct exec_domain	*exec_domain;	/* execution domain */
29	__u32			flags;		/* low level flags */
30	__u32			status;		/* thread synchronous flags */
31	__u32			cpu;		/* current CPU */
32	int 			preempt_count;	/* 0 => preemptable, <0 => BUG */
33
34	mm_segment_t		addr_limit;
35	struct restart_block    restart_block;
36};
37#endif
38
39/*
40 * macros/functions for gaining access to the thread information structure
41 * preempt_count needs to be 1 initially, until the scheduler is functional.
42 */
43#ifndef __ASSEMBLY__
44#define INIT_THREAD_INFO(tsk)			\
45{						\
46	.task	       = &tsk,			\
47	.exec_domain   = &default_exec_domain,	\
48	.flags	       = 0,			\
49	.cpu	       = 0,			\
50	.preempt_count = 1,			\
51	.addr_limit     = KERNEL_DS,		\
52	.restart_block = {			\
53		.fn = do_no_restart_syscall,	\
54	},					\
55}
56
57#define init_thread_info	(init_thread_union.thread_info)
58#define init_stack		(init_thread_union.stack)
59
60static inline struct thread_info *current_thread_info(void)
61{
62	struct thread_info *ti;
63	ti = (void *)(read_pda(kernelstack) + PDA_STACKOFFSET - THREAD_SIZE);
64	return ti;
65}
66
67/* do not use in interrupt context */
68static inline struct thread_info *stack_thread_info(void)
69{
70	struct thread_info *ti;
71	__asm__("andq %%rsp,%0; ":"=r" (ti) : "0" (~(THREAD_SIZE - 1)));
72	return ti;
73}
74
75/* thread information allocation */
76#ifdef CONFIG_DEBUG_STACK_USAGE
77#define alloc_thread_info(tsk)					\
78    ({								\
79	struct thread_info *ret;				\
80								\
81	ret = ((struct thread_info *) __get_free_pages(GFP_KERNEL,THREAD_ORDER)); \
82	if (ret)						\
83		memset(ret, 0, THREAD_SIZE);			\
84	ret;							\
85    })
86#else
87#define alloc_thread_info(tsk) \
88	((struct thread_info *) __get_free_pages(GFP_KERNEL,THREAD_ORDER))
89#endif
90
91#define free_thread_info(ti) free_pages((unsigned long) (ti), THREAD_ORDER)
92
93#else /* !__ASSEMBLY__ */
94
95/* how to get the thread information struct from ASM */
96#define GET_THREAD_INFO(reg) \
97	movq %gs:pda_kernelstack,reg ; \
98	subq $(THREAD_SIZE-PDA_STACKOFFSET),reg
99
100#endif
101
102/*
103 * thread information flags
104 * - these are process state flags that various assembly files may need to access
105 * - pending work-to-be-done flags are in LSW
106 * - other flags in MSW
107 * Warning: layout of LSW is hardcoded in entry.S
108 */
109#define TIF_SYSCALL_TRACE	0	/* syscall trace active */
110#define TIF_NOTIFY_RESUME	1	/* resumption notification requested */
111#define TIF_SIGPENDING		2	/* signal pending */
112#define TIF_NEED_RESCHED	3	/* rescheduling necessary */
113#define TIF_SINGLESTEP		4	/* reenable singlestep on user return*/
114#define TIF_IRET		5	/* force IRET */
115#define TIF_SYSCALL_AUDIT	7	/* syscall auditing active */
116#define TIF_SECCOMP		8	/* secure computing */
117#define TIF_RESTORE_SIGMASK	9	/* restore signal mask in do_signal */
118/* 16 free */
119#define TIF_IA32		17	/* 32bit process */
120#define TIF_FORK		18	/* ret_from_fork */
121#define TIF_ABI_PENDING		19
122#define TIF_MEMDIE		20
123#define TIF_DEBUG		21	/* uses debug registers */
124#define TIF_IO_BITMAP		22	/* uses I/O bitmap */
125#define TIF_FREEZE		23	/* is freezing for suspend */
126
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_SINGLESTEP		(1<<TIF_SINGLESTEP)
131#define _TIF_NEED_RESCHED	(1<<TIF_NEED_RESCHED)
132#define _TIF_IRET		(1<<TIF_IRET)
133#define _TIF_SYSCALL_AUDIT	(1<<TIF_SYSCALL_AUDIT)
134#define _TIF_SECCOMP		(1<<TIF_SECCOMP)
135#define _TIF_RESTORE_SIGMASK	(1<<TIF_RESTORE_SIGMASK)
136#define _TIF_IA32		(1<<TIF_IA32)
137#define _TIF_FORK		(1<<TIF_FORK)
138#define _TIF_ABI_PENDING	(1<<TIF_ABI_PENDING)
139#define _TIF_DEBUG		(1<<TIF_DEBUG)
140#define _TIF_IO_BITMAP		(1<<TIF_IO_BITMAP)
141#define _TIF_FREEZE		(1<<TIF_FREEZE)
142
143/* work to do on interrupt/exception return */
144#define _TIF_WORK_MASK \
145  (0x0000FFFF & ~(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP|_TIF_SECCOMP))
146/* work to do on any return to user space */
147#define _TIF_ALLWORK_MASK (0x0000FFFF & ~_TIF_SECCOMP)
148
149/* flags to check in __switch_to() */
150#define _TIF_WORK_CTXSW (_TIF_DEBUG|_TIF_IO_BITMAP)
151
152#define PREEMPT_ACTIVE     0x10000000
153
154/*
155 * Thread-synchronous status.
156 *
157 * This is different from the flags in that nobody else
158 * ever touches our thread-synchronous status, so we don't
159 * have to worry about atomic accesses.
160 */
161#define TS_USEDFPU		0x0001	/* FPU was used by this task this quantum (SMP) */
162#define TS_COMPAT		0x0002	/* 32bit syscall active */
163#define TS_POLLING		0x0004	/* true if in idle loop and not sleeping */
164
165#define tsk_is_polling(t) (task_thread_info(t)->status & TS_POLLING)
166
167#endif /* __KERNEL__ */
168
169#endif /* _ASM_THREAD_INFO_H */
170