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 <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, the assembly constants must also be changed
  24  */
  25 #ifndef __ASSEMBLY__
  26
  27 struct thread_info {
  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 */
  34
  35
  36         mm_segment_t            addr_limit;     /* thread address space:
  37                                                    0-0xBFFFFFFF for user-thead
  38                                                    0-0xFFFFFFFF for kernel-thread
  39                                                 */
  40         void                    *sysenter_return;
  41         void                    *real_stack, *virtual_stack, *user_pgd;
  42         struct restart_block    restart_block;
  43
  44         unsigned long           previous_esp;   /* ESP of the previous stack in case
  45                                                    of nested (IRQ) stacks
  46                                                 */
  47         __u8                    supervisor_stack[0];
  48 };
  49
  50 #else /* !__ASSEMBLY__ */
  51
  52 #include <asm/asm_offsets.h>
  53
  54 #endif
  55
  56 #define PREEMPT_ACTIVE          0x4000000
  57 #define THREAD_SIZE            (1<<CONFIG_STACK_SIZE_SHIFT)
  58 #define STACK_WARN             (CONFIG_STACK_WARN)
  59
  60 /*
  61  * macros/functions for gaining access to the thread information structure
  62  *
  63  * preempt_count needs to be 1 initially, until the scheduler is functional.
  64  */
  65 #ifndef __ASSEMBLY__
  66
  67 #define INIT_THREAD_INFO(tsk, thread_info)      \
  68 {                                               \
  69         .task           = &tsk,                 \
  70         .exec_domain    = &default_exec_domain, \
  71         .flags          = 0,                    \
  72         .cpu            = 0,                    \
  73         .preempt_count  = 1,                    \
  74         .addr_limit     = KERNEL_DS,            \
  75         .restart_block = {                      \
  76                 .fn = do_no_restart_syscall,    \
  77         },                                      \
  78         .real_stack     = &thread_info,         \
  79 }
  80
  81 #define init_thread_info        (init_thread_union.thread_info)
  82 #define init_stack              (init_thread_union.stack)
  83
  84
  85 /* how to get the thread information struct from C */
  86 static inline struct thread_info *current_thread_info(void)
  87 {
  88         struct thread_info *ti;
  89         __asm__("andl %%esp,%0; ":"=r" (ti) : "0" (~(THREAD_SIZE - 1)));
  90         return ti;
  91 }
  92
  93 /* how to get the current stack pointer from C */
  94 static inline unsigned long current_stack_pointer(void)
  95 {
  96         unsigned long ti;
  97         __asm__("movl %%esp,%0; ":"=r" (ti) : );
  98         return ti;
  99 }
 100
 101 /* thread information allocation */
 102 #ifdef CONFIG_DEBUG_STACK_USAGE
 103 #define alloc_thread_info(tsk)                                  \
 104         ({                                                      \
 105                 struct thread_info *ret;                        \
 106                                                                 \
 107                 ret = kmalloc(THREAD_SIZE, GFP_KERNEL);         \
 108                 if (ret)                                        \
 109                         memset(ret, 0, THREAD_SIZE);            \
 110                 ret;                                            \
 111         })
 112 #else
 113 #define alloc_thread_info(tsk) kmalloc(THREAD_SIZE, GFP_KERNEL)
 114 #endif
 115
 116 #define free_thread_info(info)  kfree(info)
 117 #define get_thread_info(ti) get_task_struct((ti)->task)
 118 #define put_thread_info(ti) put_task_struct((ti)->task)
 119
 120 #else /* !__ASSEMBLY__ */
 121
 122 /* how to get the thread information struct from ASM */
 123 #define GET_THREAD_INFO(reg) \
 124         movl $-THREAD_SIZE, reg; \
 125         andl %esp, reg
 126
 127 /* use this one if reg already contains %esp */
 128 #define GET_THREAD_INFO_WITH_ESP(reg) \
 129         andl $-THREAD_SIZE, reg
 130
 131 #endif
 132
 133 /*
 134  * thread information flags
 135  * - these are process state flags that various assembly files may need to access
 136  * - pending work-to-be-done flags are in LSW
 137  * - other flags in MSW
 138  */
 139 #define TIF_SYSCALL_TRACE       0       /* syscall trace active */
 140 #define TIF_NOTIFY_RESUME       1       /* resumption notification requested */
 141 #define TIF_SIGPENDING          2       /* signal pending */
 142 #define TIF_NEED_RESCHED        3       /* rescheduling necessary */
 143 #define TIF_SINGLESTEP          4       /* restore singlestep on return to user mode */
 144 #define TIF_IRET                5       /* return with iret */
 145 #define TIF_DB7                 6       /* has debug registers */
 146 #define TIF_SYSCALL_AUDIT       7       /* syscall auditing active */
 147 #define TIF_POLLING_NRFLAG      16      /* true if poll_idle() is polling TIF_NEED_RESCHED */
 148
 149 #define _TIF_SYSCALL_TRACE      (1<<TIF_SYSCALL_TRACE)
 150 #define _TIF_NOTIFY_RESUME      (1<<TIF_NOTIFY_RESUME)
 151 #define _TIF_SIGPENDING         (1<<TIF_SIGPENDING)
 152 #define _TIF_NEED_RESCHED       (1<<TIF_NEED_RESCHED)
 153 #define _TIF_SINGLESTEP         (1<<TIF_SINGLESTEP)
 154 #define _TIF_IRET               (1<<TIF_IRET)
 155 #define _TIF_SYSCALL_AUDIT      (1<<TIF_SYSCALL_AUDIT)
 156 #define _TIF_DB7                (1<<TIF_DB7)
 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))
 162 #define _TIF_ALLWORK_MASK       0x0000FFFF      /* work to do on any return to u-space */
 163
 164 /*
 165  * Thread-synchronous status.
 166  *
 167  * This is different from the flags in that nobody else
 168  * ever touches our thread-synchronous status, so we don't
 169  * have to worry about atomic accesses.
 170  */
 171 #define TS_USEDFPU              0x0001  /* FPU was used by this task this quantum (SMP) */
 172
 173 #endif /* __KERNEL__ */
 174
 175 #endif /* _ASM_THREAD_INFO_H */