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         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 /* offsets into the thread_info struct for assembly code access */
  51 #define TI_TASK         0x00000000
  52 #define TI_EXEC_DOMAIN  0x00000004
  53 #define TI_FLAGS        0x00000008
  54 #define TI_STATUS       0x0000000C
  55 #define TI_CPU          0x00000010
  56 #define TI_PRE_COUNT    0x00000014
  57 #define TI_ADDR_LIMIT   0x00000018
  58 #define TI_RESTART_BLOCK 0x000001C
  59
  60 #endif
  61
  62 #define PREEMPT_ACTIVE          0x4000000
  63 #ifdef CONFIG_4KSTACKS
  64 #define THREAD_SIZE            (4096)
  65 #else
  66 #define THREAD_SIZE             (8192)
  67 #endif
  68
  69 #define STACK_WARN             (THREAD_SIZE/8)
  70 /*
  71  * macros/functions for gaining access to the thread information structure
  72  *
  73  * preempt_count needs to be 1 initially, until the scheduler is functional.
  74  */
  75 #ifndef __ASSEMBLY__
  76
  77 #define INIT_THREAD_INFO(tsk)                   \
  78 {                                               \
  79         .task           = &tsk,                 \
  80         .exec_domain    = &default_exec_domain, \
  81         .flags          = 0,                    \
  82         .cpu            = 0,                    \
  83         .preempt_count  = 1,                    \
  84         .addr_limit     = KERNEL_DS,            \
  85         .restart_block = {                      \
  86                 .fn = do_no_restart_syscall,    \
  87         },                                      \
  88 }
  89
  90 #define init_thread_info        (init_thread_union.thread_info)
  91 #define init_stack              (init_thread_union.stack)
  92
  93
  94 /* how to get the thread information struct from C */
  95 static inline struct thread_info *current_thread_info(void)
  96 {
  97         struct thread_info *ti;
  98         __asm__("andl %%esp,%0; ":"=r" (ti) : "0" (~(THREAD_SIZE - 1)));
  99         return ti;
 100 }
 101
 102 /* how to get the current stack pointer from C */
 103 static inline unsigned long current_stack_pointer(void)
 104 {
 105         unsigned long ti;
 106         __asm__("movl %%esp,%0; ":"=r" (ti) : );
 107         return ti;
 108 }
 109
 110 /* thread information allocation */
 111 #ifdef CONFIG_DEBUG_STACK_USAGE
 112 #define alloc_thread_info(tsk)                                  \
 113         ({                                                      \
 114                 struct thread_info *ret;                        \
 115                                                                 \
 116                 ret = kmalloc(THREAD_SIZE, GFP_KERNEL);         \
 117                 if (ret)                                        \
 118                         memset(ret, 0, THREAD_SIZE);            \
 119                 ret;                                            \
 120         })
 121 #else
 122 #define alloc_thread_info(tsk) kmalloc(THREAD_SIZE, GFP_KERNEL)
 123 #endif
 124
 125 #define free_thread_info(info)  kfree(info)
 126 #define get_thread_info(ti) get_task_struct((ti)->task)
 127 #define put_thread_info(ti) put_task_struct((ti)->task)
 128
 129 #else /* !__ASSEMBLY__ */
 130
 131 /* how to get the thread information struct from ASM */
 132 #define GET_THREAD_INFO(reg) \
 133         movl $-THREAD_SIZE, reg; \
 134         andl %esp, reg
 135
 136 /* use this one if reg already contains %esp */
 137 #define GET_THREAD_INFO_WITH_ESP(reg) \
 138         andl $-THREAD_SIZE, reg
 139
 140 #endif
 141
 142 /*
 143  * thread information flags
 144  * - these are process state flags that various assembly files may need to access
 145  * - pending work-to-be-done flags are in LSW
 146  * - other flags in MSW
 147  */
 148 #define TIF_SYSCALL_TRACE       0       /* syscall trace active */
 149 #define TIF_NOTIFY_RESUME       1       /* resumption notification requested */
 150 #define TIF_SIGPENDING          2       /* signal pending */
 151 #define TIF_NEED_RESCHED        3       /* rescheduling necessary */
 152 #define TIF_SINGLESTEP          4       /* restore singlestep on return to user mode */
 153 #define TIF_IRET                5       /* return with iret */
 154 #define TIF_SYSCALL_AUDIT       7       /* syscall auditing active */
 155 #define TIF_POLLING_NRFLAG      16      /* true if poll_idle() is polling TIF_NEED_RESCHED */
 156
 157 #define _TIF_SYSCALL_TRACE      (1<<TIF_SYSCALL_TRACE)
 158 #define _TIF_NOTIFY_RESUME      (1<<TIF_NOTIFY_RESUME)
 159 #define _TIF_SIGPENDING         (1<<TIF_SIGPENDING)
 160 #define _TIF_NEED_RESCHED       (1<<TIF_NEED_RESCHED)
 161 #define _TIF_SINGLESTEP         (1<<TIF_SINGLESTEP)
 162 #define _TIF_IRET               (1<<TIF_IRET)
 163 #define _TIF_SYSCALL_AUDIT      (1<<TIF_SYSCALL_AUDIT)
 164 #define _TIF_POLLING_NRFLAG     (1<<TIF_POLLING_NRFLAG)
 165
 166 /* work to do on interrupt/exception return */
 167 #define _TIF_WORK_MASK \
 168   (0x0000FFFF & ~(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT))
 169 #define _TIF_ALLWORK_MASK       0x0000FFFF      /* work to do on any return to u-space */
 170
 171 /*
 172  * Thread-synchronous status.
 173  *
 174  * This is different from the flags in that nobody else
 175  * ever touches our thread-synchronous status, so we don't
 176  * have to worry about atomic accesses.
 177  */
 178 #define TS_USEDFPU              0x0001  /* FPU was used by this task this quantum (SMP) */
 179
 180 #endif /* __KERNEL__ */
 181
 182 #endif /* _ASM_THREAD_INFO_H */