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 <linux/compiler.h>
  14 #include <asm/page.h>
  15
  16 #ifndef __ASSEMBLY__
  17 #include <asm/processor.h>
  18 #endif
  19
  20 /*
  21  * low level task data that entry.S needs immediate access to
  22  * - this struct should fit entirely inside of one cache line
  23  * - this struct shares the supervisor stack pages
  24  * - if the contents of this structure are changed, the assembly constants must also be changed
  25  */
  26 #ifndef __ASSEMBLY__
  27
  28 struct 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, <0 => BUG */
  35
  36
  37         mm_segment_t            addr_limit;     /* thread address space:
  38                                                    0-0xBFFFFFFF for user-thead
  39                                                    0-0xFFFFFFFF for kernel-thread
  40                                                 */
  41         void                    *sysenter_return;
  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          0x10000000
  57 #ifdef CONFIG_4KSTACKS
  58 #define THREAD_SIZE            (4096)
  59 #else
  60 #define THREAD_SIZE             (8192)
  61 #endif
  62
  63 #define STACK_WARN             (THREAD_SIZE/8)
  64 /*
  65  * macros/functions for gaining access to the thread information structure
  66  *
  67  * preempt_count needs to be 1 initially, until the scheduler is functional.
  68  */
  69 #ifndef __ASSEMBLY__
  70
  71 #define INIT_THREAD_INFO(tsk)                   \
  72 {                                               \
  73         .task           = &tsk,                 \
  74         .exec_domain    = &default_exec_domain, \
  75         .flags          = 0,                    \
  76         .cpu            = 0,                    \
  77         .preempt_count  = 1,                    \
  78         .addr_limit     = KERNEL_DS,            \
  79         .restart_block = {                      \
  80                 .fn = do_no_restart_syscall,    \
  81         },                                      \
  82 }
  83
  84 #define init_thread_info        (init_thread_union.thread_info)
  85 #define init_stack              (init_thread_union.stack)
  86
  87
  88 /* how to get the thread information struct from C */
  89 static inline struct thread_info *current_thread_info(void)
  90 {
  91         struct thread_info *ti;
  92         __asm__("andl %%esp,%0; ":"=r" (ti) : "0" (~(THREAD_SIZE - 1)));
  93         return ti;
  94 }
  95
  96 /* how to get the current stack pointer from C */
  97 register unsigned long current_stack_pointer asm("esp") __attribute_used__;
  98
  99 /* thread information allocation */
 100 #ifdef CONFIG_DEBUG_STACK_USAGE
 101 #define alloc_thread_info(tsk)                                  \
 102         ({                                                      \
 103                 struct thread_info *ret;                        \
 104                                                                 \
 105                 ret = kmalloc(THREAD_SIZE, GFP_KERNEL);         \
 106                 if (ret)                                        \
 107                         memset(ret, 0, THREAD_SIZE);            \
 108                 ret;                                            \
 109         })
 110 #else
 111 #define alloc_thread_info(tsk) kmalloc(THREAD_SIZE, GFP_KERNEL)
 112 #endif
 113
 114 #define free_thread_info(info)  kfree(info)
 115
 116 #else /* !__ASSEMBLY__ */
 117
 118 /* how to get the thread information struct from ASM */
 119 #define GET_THREAD_INFO(reg) \
 120         movl $-THREAD_SIZE, reg; \
 121         andl %esp, reg
 122
 123 /* use this one if reg already contains %esp */
 124 #define GET_THREAD_INFO_WITH_ESP(reg) \
 125         andl $-THREAD_SIZE, reg
 126
 127 #endif
 128
 129 /*
 130  * thread information flags
 131  * - these are process state flags that various assembly files may need to access
 132  * - pending work-to-be-done flags are in LSW
 133  * - other flags in MSW
 134  */
 135 #define TIF_SYSCALL_TRACE       0       /* syscall trace active */
 136 #define TIF_NOTIFY_RESUME       1       /* resumption notification requested */
 137 #define TIF_SIGPENDING          2       /* signal pending */
 138 #define TIF_NEED_RESCHED        3       /* rescheduling necessary */
 139 #define TIF_SINGLESTEP          4       /* restore singlestep on return to user mode */
 140 #define TIF_IRET                5       /* return with iret */
 141 #define TIF_SYSCALL_EMU         6       /* syscall emulation active */
 142 #define TIF_SYSCALL_AUDIT       7       /* syscall auditing active */
 143 #define TIF_SECCOMP             8       /* secure computing */
 144 #define TIF_RESTORE_SIGMASK     9       /* restore signal mask in do_signal() */
 145 #define TIF_POLLING_NRFLAG      16      /* true if poll_idle() is polling TIF_NEED_RESCHED */
 146 #define TIF_MEMDIE              17
 147
 148 #define _TIF_SYSCALL_TRACE      (1<<TIF_SYSCALL_TRACE)
 149 #define _TIF_NOTIFY_RESUME      (1<<TIF_NOTIFY_RESUME)
 150 #define _TIF_SIGPENDING         (1<<TIF_SIGPENDING)
 151 #define _TIF_NEED_RESCHED       (1<<TIF_NEED_RESCHED)
 152 #define _TIF_SINGLESTEP         (1<<TIF_SINGLESTEP)
 153 #define _TIF_IRET               (1<<TIF_IRET)
 154 #define _TIF_SYSCALL_EMU        (1<<TIF_SYSCALL_EMU)
 155 #define _TIF_SYSCALL_AUDIT      (1<<TIF_SYSCALL_AUDIT)
 156 #define _TIF_SECCOMP            (1<<TIF_SECCOMP)
 157 #define _TIF_RESTORE_SIGMASK    (1<<TIF_RESTORE_SIGMASK)
 158 #define _TIF_POLLING_NRFLAG     (1<<TIF_POLLING_NRFLAG)
 159
 160 /* work to do on interrupt/exception return */
 161 #define _TIF_WORK_MASK \
 162   (0x0000FFFF & ~(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
 163                   _TIF_SECCOMP | _TIF_SYSCALL_EMU))
 164 /* work to do on any return to u-space */
 165 #define _TIF_ALLWORK_MASK       (0x0000FFFF & ~_TIF_SECCOMP)
 166
 167 /*
 168  * Thread-synchronous status.
 169  *
 170  * This is different from the flags in that nobody else
 171  * ever touches our thread-synchronous status, so we don't
 172  * have to worry about atomic accesses.
 173  */
 174 #define TS_USEDFPU              0x0001  /* FPU was used by this task this quantum (SMP) */
 175
 176 #endif /* __KERNEL__ */
 177
 178 #endif /* _ASM_THREAD_INFO_H */