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/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, 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         int                     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         struct restart_block    restart_block;
  41
  42         unsigned long           previous_esp;   /* ESP of the previous stack in case
  43                                                    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 */
  87 register unsigned long current_stack_pointer asm("esp") __attribute_used__;
  88
  89 /* how to get the thread information struct from C */
  90 static inline struct thread_info *current_thread_info(void)
  91 {
  92         return (struct thread_info *)(current_stack_pointer & ~(THREAD_SIZE - 1));
  93 }
  94
  95 /* thread information allocation */
  96 #ifdef CONFIG_DEBUG_STACK_USAGE
  97 #define alloc_thread_info(tsk)                                  \
  98         ({                                                      \
  99                 struct thread_info *ret;                        \
 100                                                                 \
 101                 ret = kmalloc(THREAD_SIZE, GFP_KERNEL);         \
 102                 if (ret)                                        \
 103                         memset(ret, 0, THREAD_SIZE);            \
 104                 ret;                                            \
 105         })
 106 #else
 107 #define alloc_thread_info(tsk) kmalloc(THREAD_SIZE, GFP_KERNEL)
 108 #endif
 109
 110 #define free_thread_info(info)  kfree(info)
 111
 112 #else /* !__ASSEMBLY__ */
 113
 114 /* how to get the thread information struct from ASM */
 115 #define GET_THREAD_INFO(reg) \
 116         movl $-THREAD_SIZE, reg; \
 117         andl %esp, reg
 118
 119 /* use this one if reg already contains %esp */
 120 #define GET_THREAD_INFO_WITH_ESP(reg) \
 121         andl $-THREAD_SIZE, reg
 122
 123 #endif
 124
 125 /*
 126  * thread information flags
 127  * - these are process state flags that various assembly files may need to access
 128  * - pending work-to-be-done flags are in LSW
 129  * - other flags in MSW
 130  */
 131 #define TIF_SYSCALL_TRACE       0       /* syscall trace active */
 132 #define TIF_NOTIFY_RESUME       1       /* resumption notification requested */
 133 #define TIF_SIGPENDING          2       /* signal pending */
 134 #define TIF_NEED_RESCHED        3       /* rescheduling necessary */
 135 #define TIF_SINGLESTEP          4       /* restore singlestep on return to user mode */
 136 #define TIF_IRET                5       /* return with iret */
 137 #define TIF_SYSCALL_EMU         6       /* syscall emulation active */
 138 #define TIF_SYSCALL_AUDIT       7       /* syscall auditing active */
 139 #define TIF_SECCOMP             8       /* secure computing */
 140 #define TIF_RESTORE_SIGMASK     9       /* restore signal mask in do_signal() */
 141 #define TIF_MEMDIE              16
 142
 143 #define _TIF_SYSCALL_TRACE      (1<<TIF_SYSCALL_TRACE)
 144 #define _TIF_NOTIFY_RESUME      (1<<TIF_NOTIFY_RESUME)
 145 #define _TIF_SIGPENDING         (1<<TIF_SIGPENDING)
 146 #define _TIF_NEED_RESCHED       (1<<TIF_NEED_RESCHED)
 147 #define _TIF_SINGLESTEP         (1<<TIF_SINGLESTEP)
 148 #define _TIF_IRET               (1<<TIF_IRET)
 149 #define _TIF_SYSCALL_EMU        (1<<TIF_SYSCALL_EMU)
 150 #define _TIF_SYSCALL_AUDIT      (1<<TIF_SYSCALL_AUDIT)
 151 #define _TIF_SECCOMP            (1<<TIF_SECCOMP)
 152 #define _TIF_RESTORE_SIGMASK    (1<<TIF_RESTORE_SIGMASK)
 153
 154 /* work to do on interrupt/exception return */
 155 #define _TIF_WORK_MASK \
 156   (0x0000FFFF & ~(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
 157                   _TIF_SECCOMP | _TIF_SYSCALL_EMU))
 158 /* work to do on any return to u-space */
 159 #define _TIF_ALLWORK_MASK       (0x0000FFFF & ~_TIF_SECCOMP)
 160
 161 /*
 162  * Thread-synchronous status.
 163  *
 164  * This is different from the flags in that nobody else
 165  * ever touches our thread-synchronous status, so we don't
 166  * have to worry about atomic accesses.
 167  */
 168 #define TS_USEDFPU              0x0001  /* FPU was used by this task this quantum (SMP) */
 169 #define TS_POLLING              0x0002  /* True if in idle loop and not sleeping */
 170
 171 #define tsk_is_polling(t) ((t)->thread_info->status & TS_POLLING)
 172
 173 #endif /* __KERNEL__ */
 174
 175 #endif /* _ASM_THREAD_INFO_H */