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   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         void                    *sysenter_return;
  41         struct restart_block    restart_block;
  42
  43         unsigned long           previous_esp;   /* ESP of the previous stack in case
  44                                                    of nested (IRQ) stacks
  45                                                 */
  46         __u8                    supervisor_stack[0];
  47 };
  48
  49 #else /* !__ASSEMBLY__ */
  50
  51 #include <asm/asm-offsets.h>
  52
  53 #endif
  54
  55 #define PREEMPT_ACTIVE          0x10000000
  56 #ifdef CONFIG_4KSTACKS
  57 #define THREAD_SIZE            (4096)
  58 #else
  59 #define THREAD_SIZE             (8192)
  60 #endif
  61
  62 #define STACK_WARN             (THREAD_SIZE/8)
  63 /*
  64  * macros/functions for gaining access to the thread information structure
  65  *
  66  * preempt_count needs to be 1 initially, until the scheduler is functional.
  67  */
  68 #ifndef __ASSEMBLY__
  69
  70 #define INIT_THREAD_INFO(tsk)                   \
  71 {                                               \
  72         .task           = &tsk,                 \
  73         .exec_domain    = &default_exec_domain, \
  74         .flags          = 0,                    \
  75         .cpu            = 0,                    \
  76         .preempt_count  = 1,                    \
  77         .addr_limit     = KERNEL_DS,            \
  78         .restart_block = {                      \
  79                 .fn = do_no_restart_syscall,    \
  80         },                                      \
  81 }
  82
  83 #define init_thread_info        (init_thread_union.thread_info)
  84 #define init_stack              (init_thread_union.stack)
  85
  86
  87 /* how to get the current stack pointer from C */
  88 register unsigned long current_stack_pointer asm("esp") __attribute_used__;
  89
  90 /* how to get the thread information struct from C */
  91 static inline struct thread_info *current_thread_info(void)
  92 {
  93         return (struct thread_info *)(current_stack_pointer & ~(THREAD_SIZE - 1));
  94 }
  95
  96 /* thread information allocation */
  97 #ifdef CONFIG_DEBUG_STACK_USAGE
  98 #define alloc_thread_info(tsk)                                  \
  99         ({                                                      \
 100                 struct thread_info *ret;                        \
 101                                                                 \
 102                 ret = kmalloc(THREAD_SIZE, GFP_KERNEL);         \
 103                 if (ret)                                        \
 104                         memset(ret, 0, THREAD_SIZE);            \
 105                 ret;                                            \
 106         })
 107 #else
 108 #define alloc_thread_info(tsk) kmalloc(THREAD_SIZE, GFP_KERNEL)
 109 #endif
 110
 111 #define free_thread_info(info)  kfree(info)
 112
 113 #else /* !__ASSEMBLY__ */
 114
 115 /* how to get the thread information struct from ASM */
 116 #define GET_THREAD_INFO(reg) \
 117         movl $-THREAD_SIZE, reg; \
 118         andl %esp, reg
 119
 120 /* use this one if reg already contains %esp */
 121 #define GET_THREAD_INFO_WITH_ESP(reg) \
 122         andl $-THREAD_SIZE, reg
 123
 124 #endif
 125
 126 /*
 127  * thread information flags
 128  * - these are process state flags that various assembly files may need to access
 129  * - pending work-to-be-done flags are in LSW
 130  * - other flags in MSW
 131  */
 132 #define TIF_SYSCALL_TRACE       0       /* syscall trace active */
 133 #define TIF_NOTIFY_RESUME       1       /* resumption notification requested */
 134 #define TIF_SIGPENDING          2       /* signal pending */
 135 #define TIF_NEED_RESCHED        3       /* rescheduling necessary */
 136 #define TIF_SINGLESTEP          4       /* restore singlestep on return to user mode */
 137 #define TIF_IRET                5       /* return with iret */
 138 #define TIF_SYSCALL_EMU         6       /* syscall emulation active */
 139 #define TIF_SYSCALL_AUDIT       7       /* syscall auditing active */
 140 #define TIF_SECCOMP             8       /* secure computing */
 141 #define TIF_RESTORE_SIGMASK     9       /* restore signal mask in do_signal() */
 142 #define TIF_MEMDIE              16
 143 #define TIF_DEBUG               17      /* uses debug registers */
 144 #define TIF_IO_BITMAP           18      /* uses I/O bitmap */
 145
 146 #define _TIF_SYSCALL_TRACE      (1<<TIF_SYSCALL_TRACE)
 147 #define _TIF_NOTIFY_RESUME      (1<<TIF_NOTIFY_RESUME)
 148 #define _TIF_SIGPENDING         (1<<TIF_SIGPENDING)
 149 #define _TIF_NEED_RESCHED       (1<<TIF_NEED_RESCHED)
 150 #define _TIF_SINGLESTEP         (1<<TIF_SINGLESTEP)
 151 #define _TIF_IRET               (1<<TIF_IRET)
 152 #define _TIF_SYSCALL_EMU        (1<<TIF_SYSCALL_EMU)
 153 #define _TIF_SYSCALL_AUDIT      (1<<TIF_SYSCALL_AUDIT)
 154 #define _TIF_SECCOMP            (1<<TIF_SECCOMP)
 155 #define _TIF_RESTORE_SIGMASK    (1<<TIF_RESTORE_SIGMASK)
 156 #define _TIF_DEBUG              (1<<TIF_DEBUG)
 157 #define _TIF_IO_BITMAP          (1<<TIF_IO_BITMAP)
 158
 159 /* work to do on interrupt/exception return */
 160 #define _TIF_WORK_MASK \
 161   (0x0000FFFF & ~(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
 162                   _TIF_SECCOMP | _TIF_SYSCALL_EMU))
 163 /* work to do on any return to u-space */
 164 #define _TIF_ALLWORK_MASK       (0x0000FFFF & ~_TIF_SECCOMP)
 165
 166 /* flags to check in __switch_to() */
 167 #define _TIF_WORK_CTXSW (_TIF_DEBUG|_TIF_IO_BITMAP)
 168
 169 /*
 170  * Thread-synchronous status.
 171  *
 172  * This is different from the flags in that nobody else
 173  * ever touches our thread-synchronous status, so we don't
 174  * have to worry about atomic accesses.
 175  */
 176 #define TS_USEDFPU              0x0001  /* FPU was used by this task this quantum (SMP) */
 177 #define TS_POLLING              0x0002  /* True if in idle loop and not sleeping */
 178
 179 #define tsk_is_polling(t) ((t)->thread_info->status & TS_POLLING)
 180
 181 #endif /* __KERNEL__ */
 182
 183 #endif /* _ASM_THREAD_INFO_H */