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 <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
  28struct 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        __s32                   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        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 thread information struct from C */
  88static inline struct thread_info *current_thread_info(void)
  89{
  90        struct thread_info *ti;
  91        __asm__("andl %%esp,%0; ":"=r" (ti) : "0" (~(THREAD_SIZE - 1)));
  92        return ti;
  93}
  94
  95/* how to get the current stack pointer from C */
  96register unsigned long current_stack_pointer asm("esp") __attribute_used__;
  97
  98/* thread information allocation */
  99#ifdef CONFIG_DEBUG_STACK_USAGE
 100#define alloc_thread_info(tsk)                                  \
 101        ({                                                      \
 102                struct thread_info *ret;                        \
 103                                                                \
 104                ret = kmalloc(THREAD_SIZE, GFP_KERNEL);         \
 105                if (ret)                                        \
 106                        memset(ret, 0, THREAD_SIZE);            \
 107                ret;                                            \
 108        })
 109#else
 110#define alloc_thread_info(tsk) kmalloc(THREAD_SIZE, GFP_KERNEL)
 111#endif
 112
 113#define free_thread_info(info)  kfree(info)
 114#define get_thread_info(ti) get_task_struct((ti)->task)
 115#define put_thread_info(ti) put_task_struct((ti)->task)
 116
 117#else /* !__ASSEMBLY__ */
 118
 119/* how to get the thread information struct from ASM */
 120#define GET_THREAD_INFO(reg) \
 121        movl $-THREAD_SIZE, reg; \
 122        andl %esp, reg
 123
 124/* use this one if reg already contains %esp */
 125#define GET_THREAD_INFO_WITH_ESP(reg) \
 126        andl $-THREAD_SIZE, reg
 127
 128#endif
 129
 130/*
 131 * thread information flags
 132 * - these are process state flags that various assembly files may need to access
 133 * - pending work-to-be-done flags are in LSW
 134 * - other flags in MSW
 135 */
 136#define TIF_SYSCALL_TRACE       0       /* syscall trace active */
 137#define TIF_NOTIFY_RESUME       1       /* resumption notification requested */
 138#define TIF_SIGPENDING          2       /* signal pending */
 139#define TIF_NEED_RESCHED        3       /* rescheduling necessary */
 140#define TIF_SINGLESTEP          4       /* restore singlestep on return to user mode */
 141#define TIF_IRET                5       /* return with iret */
 142#define TIF_SYSCALL_AUDIT       7       /* syscall auditing active */
 143#define TIF_POLLING_NRFLAG      16      /* true if poll_idle() is polling TIF_NEED_RESCHED */
 144#define TIF_MEMDIE              17
 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_AUDIT      (1<<TIF_SYSCALL_AUDIT)
 153#define _TIF_POLLING_NRFLAG     (1<<TIF_POLLING_NRFLAG)
 154
 155/* work to do on interrupt/exception return */
 156#define _TIF_WORK_MASK \
 157  (0x0000FFFF & ~(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP))
 158#define _TIF_ALLWORK_MASK       0x0000FFFF      /* work to do on any return to u-space */
 159
 160/*
 161 * Thread-synchronous status.
 162 *
 163 * This is different from the flags in that nobody else
 164 * ever touches our thread-synchronous status, so we don't
 165 * have to worry about atomic accesses.
 166 */
 167#define TS_USEDFPU              0x0001  /* FPU was used by this task this quantum (SMP) */
 168
 169#endif /* __KERNEL__ */
 170
 171#endif /* _ASM_THREAD_INFO_H */
 172