LXR linux-bk/include/asm-i386/thread

   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
  27struct 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#include <asm/asm_offsets.h>
  51
  52#endif
  53
  54#define PREEMPT_ACTIVE          0x4000000
  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 thread information struct from C */
  87static inline struct thread_info *current_thread_info(void)
  88{
  89        struct thread_info *ti;
  90        __asm__("andl %%esp,%0; ":"=r" (ti) : "0" (~(THREAD_SIZE - 1)));
  91        return ti;
  92}
  93
  94/* how to get the current stack pointer from C */
  95static inline unsigned long current_stack_pointer(void)
  96{
  97        unsigned long ti;
  98        __asm__("movl %%esp,%0; ":"=r" (ti) : );
  99        return ti;
 100}
 101
 102/* thread information allocation */
 103#ifdef CONFIG_DEBUG_STACK_USAGE
 104#define alloc_thread_info(tsk)                                  \
 105        ({                                                      \
 106                struct thread_info *ret;                        \
 107                                                                \
 108                ret = kmalloc(THREAD_SIZE, GFP_KERNEL);         \
 109                if (ret)                                        \
 110                        memset(ret, 0, THREAD_SIZE);            \
 111                ret;                                            \
 112        })
 113#else
 114#define alloc_thread_info(tsk) kmalloc(THREAD_SIZE, GFP_KERNEL)
 115#endif
 116
 117#define free_thread_info(info)  kfree(info)
 118#define get_thread_info(ti) get_task_struct((ti)->task)
 119#define put_thread_info(ti) put_task_struct((ti)->task)
 120
 121#else /* !__ASSEMBLY__ */
 122
 123/* how to get the thread information struct from ASM */
 124#define GET_THREAD_INFO(reg) \
 125        movl $-THREAD_SIZE, reg; \
 126        andl %esp, reg
 127
 128/* use this one if reg already contains %esp */
 129#define GET_THREAD_INFO_WITH_ESP(reg) \
 130        andl $-THREAD_SIZE, reg
 131
 132#endif
 133
 134/*
 135 * thread information flags
 136 * - these are process state flags that various assembly files may need to access
 137 * - pending work-to-be-done flags are in LSW
 138 * - other flags in MSW
 139 */
 140#define TIF_SYSCALL_TRACE       0       /* syscall trace active */
 141#define TIF_NOTIFY_RESUME       1       /* resumption notification requested */
 142#define TIF_SIGPENDING          2       /* signal pending */
 143#define TIF_NEED_RESCHED        3       /* rescheduling necessary */
 144#define TIF_SINGLESTEP          4       /* restore singlestep on return to user mode */
 145#define TIF_IRET                5       /* return with iret */
 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_POLLING_NRFLAG     (1<<TIF_POLLING_NRFLAG)
 157
 158/* work to do on interrupt/exception return */
 159#define _TIF_WORK_MASK \
 160  (0x0000FFFF & ~(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT))
 161#define _TIF_ALLWORK_MASK       0x0000FFFF      /* work to do on any return to u-space */
 162
 163/*
 164 * Thread-synchronous status.
 165 *
 166 * This is different from the flags in that nobody else
 167 * ever touches our thread-synchronous status, so we don't
 168 * have to worry about atomic accesses.
 169 */
 170#define TS_USEDFPU              0x0001  /* FPU was used by this task this quantum (SMP) */
 171
 172#endif /* __KERNEL__ */
 173
 174#endif /* _ASM_THREAD_INFO_H */
 175