root/arch/x86/include/asm/thread_info.h

INCLUDED FROM

DEFINITIONS

1. current_thread_info
2. set_restore_sigmask
3. clear_restore_sigmask
4. test_restore_sigmask
5. test_and_clear_restore_sigmask
6. is_ia32_task

/* thread_info.h: low-level thread information
 *
 * Copyright (C) 2002  David Howells (dhowells@redhat.com)
 * - Incorporating suggestions made by Linus Torvalds and Dave Miller
 */

#ifndef _ASM_X86_THREAD_INFO_H
#define _ASM_X86_THREAD_INFO_H

#include <linux/compiler.h>
#include <asm/page.h>
#include <asm/percpu.h>
#include <asm/types.h>

/*
 * low level task data that entry.S needs immediate access to
 * - this struct should fit entirely inside of one cache line
 * - this struct shares the supervisor stack pages
 */
#ifndef __ASSEMBLY__
struct task_struct;
struct exec_domain;
#include <asm/processor.h>
#include <linux/atomic.h>

struct thread_info {
        struct task_struct      *task;          /* main task structure */
        struct exec_domain      *exec_domain;   /* execution domain */
        __u32                   flags;          /* low level flags */
        __u32                   status;         /* thread synchronous flags */
        __u32                   cpu;            /* current CPU */
        int                     saved_preempt_count;
        mm_segment_t            addr_limit;
        struct restart_block    restart_block;
        void __user             *sysenter_return;
        unsigned int            sig_on_uaccess_error:1;
        unsigned int            uaccess_err:1;  /* uaccess failed */
};

#define INIT_THREAD_INFO(tsk)                   \
{                                               \
        .task           = &tsk,                 \
        .exec_domain    = &default_exec_domain, \
        .flags          = 0,                    \
        .cpu            = 0,                    \
        .saved_preempt_count = INIT_PREEMPT_COUNT,      \
        .addr_limit     = KERNEL_DS,            \
        .restart_block = {                      \
                .fn = do_no_restart_syscall,    \
        },                                      \
}

#define init_thread_info        (init_thread_union.thread_info)
#define init_stack              (init_thread_union.stack)

#else /* !__ASSEMBLY__ */

#include <asm/asm-offsets.h>

#endif

/*
 * thread information flags
 * - these are process state flags that various assembly files
 *   may need to access
 * - pending work-to-be-done flags are in LSW
 * - other flags in MSW
 * Warning: layout of LSW is hardcoded in entry.S
 */
#define TIF_SYSCALL_TRACE       0       /* syscall trace active */
#define TIF_NOTIFY_RESUME       1       /* callback before returning to user */
#define TIF_SIGPENDING          2       /* signal pending */
#define TIF_NEED_RESCHED        3       /* rescheduling necessary */
#define TIF_SINGLESTEP          4       /* reenable singlestep on user return*/
#define TIF_SYSCALL_EMU         6       /* syscall emulation active */
#define TIF_SYSCALL_AUDIT       7       /* syscall auditing active */
#define TIF_SECCOMP             8       /* secure computing */
#define TIF_MCE_NOTIFY          10      /* notify userspace of an MCE */
#define TIF_USER_RETURN_NOTIFY  11      /* notify kernel of userspace return */
#define TIF_UPROBE              12      /* breakpointed or singlestepping */
#define TIF_NOTSC               16      /* TSC is not accessible in userland */
#define TIF_IA32                17      /* IA32 compatibility process */
#define TIF_FORK                18      /* ret_from_fork */
#define TIF_NOHZ                19      /* in adaptive nohz mode */
#define TIF_MEMDIE              20      /* is terminating due to OOM killer */
#define TIF_POLLING_NRFLAG      21      /* idle is polling for TIF_NEED_RESCHED */
#define TIF_IO_BITMAP           22      /* uses I/O bitmap */
#define TIF_FORCED_TF           24      /* true if TF in eflags artificially */
#define TIF_BLOCKSTEP           25      /* set when we want DEBUGCTLMSR_BTF */
#define TIF_LAZY_MMU_UPDATES    27      /* task is updating the mmu lazily */
#define TIF_SYSCALL_TRACEPOINT  28      /* syscall tracepoint instrumentation */
#define TIF_ADDR32              29      /* 32-bit address space on 64 bits */
#define TIF_X32                 30      /* 32-bit native x86-64 binary */

#define _TIF_SYSCALL_TRACE      (1 << TIF_SYSCALL_TRACE)
#define _TIF_NOTIFY_RESUME      (1 << TIF_NOTIFY_RESUME)
#define _TIF_SIGPENDING         (1 << TIF_SIGPENDING)
#define _TIF_SINGLESTEP         (1 << TIF_SINGLESTEP)
#define _TIF_NEED_RESCHED       (1 << TIF_NEED_RESCHED)
#define _TIF_SYSCALL_EMU        (1 << TIF_SYSCALL_EMU)
#define _TIF_SYSCALL_AUDIT      (1 << TIF_SYSCALL_AUDIT)
#define _TIF_SECCOMP            (1 << TIF_SECCOMP)
#define _TIF_MCE_NOTIFY         (1 << TIF_MCE_NOTIFY)
#define _TIF_USER_RETURN_NOTIFY (1 << TIF_USER_RETURN_NOTIFY)
#define _TIF_UPROBE             (1 << TIF_UPROBE)
#define _TIF_NOTSC              (1 << TIF_NOTSC)
#define _TIF_IA32               (1 << TIF_IA32)
#define _TIF_FORK               (1 << TIF_FORK)
#define _TIF_NOHZ               (1 << TIF_NOHZ)
#define _TIF_POLLING_NRFLAG     (1 << TIF_POLLING_NRFLAG)
#define _TIF_IO_BITMAP          (1 << TIF_IO_BITMAP)
#define _TIF_FORCED_TF          (1 << TIF_FORCED_TF)
#define _TIF_BLOCKSTEP          (1 << TIF_BLOCKSTEP)
#define _TIF_LAZY_MMU_UPDATES   (1 << TIF_LAZY_MMU_UPDATES)
#define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
#define _TIF_ADDR32             (1 << TIF_ADDR32)
#define _TIF_X32                (1 << TIF_X32)

/* work to do in syscall_trace_enter() */
#define _TIF_WORK_SYSCALL_ENTRY \
        (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_EMU | _TIF_SYSCALL_AUDIT |   \
         _TIF_SECCOMP | _TIF_SINGLESTEP | _TIF_SYSCALL_TRACEPOINT |     \
         _TIF_NOHZ)

/* work to do in syscall_trace_leave() */
#define _TIF_WORK_SYSCALL_EXIT  \
        (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SINGLESTEP |    \
         _TIF_SYSCALL_TRACEPOINT | _TIF_NOHZ)

/* work to do on interrupt/exception return */
#define _TIF_WORK_MASK                                                  \
        (0x0000FFFF &                                                   \
         ~(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|                       \
           _TIF_SINGLESTEP|_TIF_SECCOMP|_TIF_SYSCALL_EMU))

/* work to do on any return to user space */
#define _TIF_ALLWORK_MASK                                               \
        ((0x0000FFFF & ~_TIF_SECCOMP) | _TIF_SYSCALL_TRACEPOINT |       \
        _TIF_NOHZ)

/* Only used for 64 bit */
#define _TIF_DO_NOTIFY_MASK                                             \
        (_TIF_SIGPENDING | _TIF_MCE_NOTIFY | _TIF_NOTIFY_RESUME |       \
         _TIF_USER_RETURN_NOTIFY | _TIF_UPROBE)

/* flags to check in __switch_to() */
#define _TIF_WORK_CTXSW                                                 \
        (_TIF_IO_BITMAP|_TIF_NOTSC|_TIF_BLOCKSTEP)

#define _TIF_WORK_CTXSW_PREV (_TIF_WORK_CTXSW|_TIF_USER_RETURN_NOTIFY)
#define _TIF_WORK_CTXSW_NEXT (_TIF_WORK_CTXSW)

#define STACK_WARN              (THREAD_SIZE/8)
#define KERNEL_STACK_OFFSET     (5*(BITS_PER_LONG/8))

/*
 * macros/functions for gaining access to the thread information structure
 *
 * preempt_count needs to be 1 initially, until the scheduler is functional.
 */
#ifndef __ASSEMBLY__

DECLARE_PER_CPU(unsigned long, kernel_stack);

static inline struct thread_info *current_thread_info(void)
{
        struct thread_info *ti;
        ti = (void *)(this_cpu_read_stable(kernel_stack) +
                      KERNEL_STACK_OFFSET - THREAD_SIZE);
        return ti;
}

#else /* !__ASSEMBLY__ */

/* how to get the thread information struct from ASM */
#define GET_THREAD_INFO(reg) \
        _ASM_MOV PER_CPU_VAR(kernel_stack),reg ; \
        _ASM_SUB $(THREAD_SIZE-KERNEL_STACK_OFFSET),reg ;

/*
 * Same if PER_CPU_VAR(kernel_stack) is, perhaps with some offset, already in
 * a certain register (to be used in assembler memory operands).
 */
#define THREAD_INFO(reg, off) KERNEL_STACK_OFFSET+(off)-THREAD_SIZE(reg)

#endif

/*
 * Thread-synchronous status.
 *
 * This is different from the flags in that nobody else
 * ever touches our thread-synchronous status, so we don't
 * have to worry about atomic accesses.
 */
#define TS_COMPAT               0x0002  /* 32bit syscall active (64BIT)*/
#define TS_RESTORE_SIGMASK      0x0008  /* restore signal mask in do_signal() */

#ifndef __ASSEMBLY__
#define HAVE_SET_RESTORE_SIGMASK        1
static inline void set_restore_sigmask(void)
{
        struct thread_info *ti = current_thread_info();
        ti->status |= TS_RESTORE_SIGMASK;
        WARN_ON(!test_bit(TIF_SIGPENDING, (unsigned long *)&ti->flags));
}
static inline void clear_restore_sigmask(void)
{
        current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
}
static inline bool test_restore_sigmask(void)
{
        return current_thread_info()->status & TS_RESTORE_SIGMASK;
}
static inline bool test_and_clear_restore_sigmask(void)
{
        struct thread_info *ti = current_thread_info();
        if (!(ti->status & TS_RESTORE_SIGMASK))
                return false;
        ti->status &= ~TS_RESTORE_SIGMASK;
        return true;
}

static inline bool is_ia32_task(void)
{
#ifdef CONFIG_X86_32
        return true;
#endif
#ifdef CONFIG_IA32_EMULATION
        if (current_thread_info()->status & TS_COMPAT)
                return true;
#endif
        return false;
}
#endif  /* !__ASSEMBLY__ */

#ifndef __ASSEMBLY__
extern void arch_task_cache_init(void);
extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src);
extern void arch_release_task_struct(struct task_struct *tsk);
#endif
#endif /* _ASM_X86_THREAD_INFO_H */