LXR linux/arch/x86/include/asm/thread

   1/* thread_info.h: 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_X86_THREAD_INFO_H
   8#define _ASM_X86_THREAD_INFO_H
   9
  10#include <linux/compiler.h>
  11#include <asm/page.h>
  12#include <asm/types.h>
  13
  14/*
  15 * low level task data that entry.S needs immediate access to
  16 * - this struct should fit entirely inside of one cache line
  17 * - this struct shares the supervisor stack pages
  18 */
  19#ifndef __ASSEMBLY__
  20struct task_struct;
  21struct exec_domain;
  22#include <asm/processor.h>
  23#include <linux/atomic.h>
  24
  25struct thread_info {
  26        struct task_struct      *task;          /* main task structure */
  27        struct exec_domain      *exec_domain;   /* execution domain */
  28        __u32                   flags;          /* low level flags */
  29        __u32                   status;         /* thread synchronous flags */
  30        __u32                   cpu;            /* current CPU */
  31        int                     preempt_count;  /* 0 => preemptable,
  32                                                   <0 => BUG */
  33        mm_segment_t            addr_limit;
  34        struct restart_block    restart_block;
  35        void __user             *sysenter_return;
  36#ifdef CONFIG_X86_32
  37        unsigned long           previous_esp;   /* ESP of the previous stack in
  38                                                   case of nested (IRQ) stacks
  39                                                */
  40        __u8                    supervisor_stack[0];
  41#endif
  42        unsigned int            sig_on_uaccess_error:1;
  43        unsigned int            uaccess_err:1;  /* uaccess failed */
  44};
  45
  46#define INIT_THREAD_INFO(tsk)                   \
  47{                                               \
  48        .task           = &tsk,                 \
  49        .exec_domain    = &default_exec_domain, \
  50        .flags          = 0,                    \
  51        .cpu            = 0,                    \
  52        .preempt_count  = INIT_PREEMPT_COUNT,   \
  53        .addr_limit     = KERNEL_DS,            \
  54        .restart_block = {                      \
  55                .fn = do_no_restart_syscall,    \
  56        },                                      \
  57}
  58
  59#define init_thread_info        (init_thread_union.thread_info)
  60#define init_stack              (init_thread_union.stack)
  61
  62#else /* !__ASSEMBLY__ */
  63
  64#include <asm/asm-offsets.h>
  65
  66#endif
  67
  68/*
  69 * thread information flags
  70 * - these are process state flags that various assembly files
  71 *   may need to access
  72 * - pending work-to-be-done flags are in LSW
  73 * - other flags in MSW
  74 * Warning: layout of LSW is hardcoded in entry.S
  75 */
  76#define TIF_SYSCALL_TRACE       0       /* syscall trace active */
  77#define TIF_NOTIFY_RESUME       1       /* callback before returning to user */
  78#define TIF_SIGPENDING          2       /* signal pending */
  79#define TIF_NEED_RESCHED        3       /* rescheduling necessary */
  80#define TIF_SINGLESTEP          4       /* reenable singlestep on user return*/
  81#define TIF_SYSCALL_EMU         6       /* syscall emulation active */
  82#define TIF_SYSCALL_AUDIT       7       /* syscall auditing active */
  83#define TIF_SECCOMP             8       /* secure computing */
  84#define TIF_MCE_NOTIFY          10      /* notify userspace of an MCE */
  85#define TIF_USER_RETURN_NOTIFY  11      /* notify kernel of userspace return */
  86#define TIF_UPROBE              12      /* breakpointed or singlestepping */
  87#define TIF_NOTSC               16      /* TSC is not accessible in userland */
  88#define TIF_IA32                17      /* IA32 compatibility process */
  89#define TIF_FORK                18      /* ret_from_fork */
  90#define TIF_NOHZ                19      /* in adaptive nohz mode */
  91#define TIF_MEMDIE              20      /* is terminating due to OOM killer */
  92#define TIF_IO_BITMAP           22      /* uses I/O bitmap */
  93#define TIF_FORCED_TF           24      /* true if TF in eflags artificially */
  94#define TIF_BLOCKSTEP           25      /* set when we want DEBUGCTLMSR_BTF */
  95#define TIF_LAZY_MMU_UPDATES    27      /* task is updating the mmu lazily */
  96#define TIF_SYSCALL_TRACEPOINT  28      /* syscall tracepoint instrumentation */
  97#define TIF_ADDR32              29      /* 32-bit address space on 64 bits */
  98#define TIF_X32                 30      /* 32-bit native x86-64 binary */
  99
 100#define _TIF_SYSCALL_TRACE      (1 << TIF_SYSCALL_TRACE)
 101#define _TIF_NOTIFY_RESUME      (1 << TIF_NOTIFY_RESUME)
 102#define _TIF_SIGPENDING         (1 << TIF_SIGPENDING)
 103#define _TIF_SINGLESTEP         (1 << TIF_SINGLESTEP)
 104#define _TIF_NEED_RESCHED       (1 << TIF_NEED_RESCHED)
 105#define _TIF_SYSCALL_EMU        (1 << TIF_SYSCALL_EMU)
 106#define _TIF_SYSCALL_AUDIT      (1 << TIF_SYSCALL_AUDIT)
 107#define _TIF_SECCOMP            (1 << TIF_SECCOMP)
 108#define _TIF_MCE_NOTIFY         (1 << TIF_MCE_NOTIFY)
 109#define _TIF_USER_RETURN_NOTIFY (1 << TIF_USER_RETURN_NOTIFY)
 110#define _TIF_UPROBE             (1 << TIF_UPROBE)
 111#define _TIF_NOTSC              (1 << TIF_NOTSC)
 112#define _TIF_IA32               (1 << TIF_IA32)
 113#define _TIF_FORK               (1 << TIF_FORK)
 114#define _TIF_NOHZ               (1 << TIF_NOHZ)
 115#define _TIF_IO_BITMAP          (1 << TIF_IO_BITMAP)
 116#define _TIF_FORCED_TF          (1 << TIF_FORCED_TF)
 117#define _TIF_BLOCKSTEP          (1 << TIF_BLOCKSTEP)
 118#define _TIF_LAZY_MMU_UPDATES   (1 << TIF_LAZY_MMU_UPDATES)
 119#define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
 120#define _TIF_ADDR32             (1 << TIF_ADDR32)
 121#define _TIF_X32                (1 << TIF_X32)
 122
 123/* work to do in syscall_trace_enter() */
 124#define _TIF_WORK_SYSCALL_ENTRY \
 125        (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_EMU | _TIF_SYSCALL_AUDIT |   \
 126         _TIF_SECCOMP | _TIF_SINGLESTEP | _TIF_SYSCALL_TRACEPOINT |     \
 127         _TIF_NOHZ)
 128
 129/* work to do in syscall_trace_leave() */
 130#define _TIF_WORK_SYSCALL_EXIT  \
 131        (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SINGLESTEP |    \
 132         _TIF_SYSCALL_TRACEPOINT | _TIF_NOHZ)
 133
 134/* work to do on interrupt/exception return */
 135#define _TIF_WORK_MASK                                                  \
 136        (0x0000FFFF &                                                   \
 137         ~(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|                       \
 138           _TIF_SINGLESTEP|_TIF_SECCOMP|_TIF_SYSCALL_EMU))
 139
 140/* work to do on any return to user space */
 141#define _TIF_ALLWORK_MASK                                               \
 142        ((0x0000FFFF & ~_TIF_SECCOMP) | _TIF_SYSCALL_TRACEPOINT |       \
 143        _TIF_NOHZ)
 144
 145/* Only used for 64 bit */
 146#define _TIF_DO_NOTIFY_MASK                                             \
 147        (_TIF_SIGPENDING | _TIF_MCE_NOTIFY | _TIF_NOTIFY_RESUME |       \
 148         _TIF_USER_RETURN_NOTIFY)
 149
 150/* flags to check in __switch_to() */
 151#define _TIF_WORK_CTXSW                                                 \
 152        (_TIF_IO_BITMAP|_TIF_NOTSC|_TIF_BLOCKSTEP)
 153
 154#define _TIF_WORK_CTXSW_PREV (_TIF_WORK_CTXSW|_TIF_USER_RETURN_NOTIFY)
 155#define _TIF_WORK_CTXSW_NEXT (_TIF_WORK_CTXSW)
 156
 157#define PREEMPT_ACTIVE          0x10000000
 158
 159#ifdef CONFIG_X86_32
 160
 161#define STACK_WARN      (THREAD_SIZE/8)
 162/*
 163 * macros/functions for gaining access to the thread information structure
 164 *
 165 * preempt_count needs to be 1 initially, until the scheduler is functional.
 166 */
 167#ifndef __ASSEMBLY__
 168
 169
 170/* how to get the current stack pointer from C */
 171register unsigned long current_stack_pointer asm("esp") __used;
 172
 173/* how to get the thread information struct from C */
 174static inline struct thread_info *current_thread_info(void)
 175{
 176        return (struct thread_info *)
 177                (current_stack_pointer & ~(THREAD_SIZE - 1));
 178}
 179
 180#else /* !__ASSEMBLY__ */
 181
 182/* how to get the thread information struct from ASM */
 183#define GET_THREAD_INFO(reg)     \
 184        movl $-THREAD_SIZE, reg; \
 185        andl %esp, reg
 186
 187/* use this one if reg already contains %esp */
 188#define GET_THREAD_INFO_WITH_ESP(reg) \
 189        andl $-THREAD_SIZE, reg
 190
 191#endif
 192
 193#else /* X86_32 */
 194
 195#include <asm/percpu.h>
 196#define KERNEL_STACK_OFFSET (5*8)
 197
 198/*
 199 * macros/functions for gaining access to the thread information structure
 200 * preempt_count needs to be 1 initially, until the scheduler is functional.
 201 */
 202#ifndef __ASSEMBLY__
 203DECLARE_PER_CPU(unsigned long, kernel_stack);
 204
 205static inline struct thread_info *current_thread_info(void)
 206{
 207        struct thread_info *ti;
 208        ti = (void *)(this_cpu_read_stable(kernel_stack) +
 209                      KERNEL_STACK_OFFSET - THREAD_SIZE);
 210        return ti;
 211}
 212
 213#else /* !__ASSEMBLY__ */
 214
 215/* how to get the thread information struct from ASM */
 216#define GET_THREAD_INFO(reg) \
 217        movq PER_CPU_VAR(kernel_stack),reg ; \
 218        subq $(THREAD_SIZE-KERNEL_STACK_OFFSET),reg
 219
 220/*
 221 * Same if PER_CPU_VAR(kernel_stack) is, perhaps with some offset, already in
 222 * a certain register (to be used in assembler memory operands).
 223 */
 224#define THREAD_INFO(reg, off) KERNEL_STACK_OFFSET+(off)-THREAD_SIZE(reg)
 225
 226#endif
 227
 228#endif /* !X86_32 */
 229
 230/*
 231 * Thread-synchronous status.
 232 *
 233 * This is different from the flags in that nobody else
 234 * ever touches our thread-synchronous status, so we don't
 235 * have to worry about atomic accesses.
 236 */
 237#define TS_COMPAT               0x0002  /* 32bit syscall active (64BIT)*/
 238#define TS_POLLING              0x0004  /* idle task polling need_resched,
 239                                           skip sending interrupt */
 240#define TS_RESTORE_SIGMASK      0x0008  /* restore signal mask in do_signal() */
 241
 242#ifndef __ASSEMBLY__
 243#define HAVE_SET_RESTORE_SIGMASK        1
 244static inline void set_restore_sigmask(void)
 245{
 246        struct thread_info *ti = current_thread_info();
 247        ti->status |= TS_RESTORE_SIGMASK;
 248        WARN_ON(!test_bit(TIF_SIGPENDING, (unsigned long *)&ti->flags));
 249}
 250static inline void clear_restore_sigmask(void)
 251{
 252        current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
 253}
 254static inline bool test_restore_sigmask(void)
 255{
 256        return current_thread_info()->status & TS_RESTORE_SIGMASK;
 257}
 258static inline bool test_and_clear_restore_sigmask(void)
 259{
 260        struct thread_info *ti = current_thread_info();
 261        if (!(ti->status & TS_RESTORE_SIGMASK))
 262                return false;
 263        ti->status &= ~TS_RESTORE_SIGMASK;
 264        return true;
 265}
 266
 267static inline bool is_ia32_task(void)
 268{
 269#ifdef CONFIG_X86_32
 270        return true;
 271#endif
 272#ifdef CONFIG_IA32_EMULATION
 273        if (current_thread_info()->status & TS_COMPAT)
 274                return true;
 275#endif
 276        return false;
 277}
 278#endif  /* !__ASSEMBLY__ */
 279
 280#ifndef __ASSEMBLY__
 281extern void arch_task_cache_init(void);
 282extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src);
 283extern void arch_release_task_struct(struct task_struct *tsk);
 284#endif
 285#endif /* _ASM_X86_THREAD_INFO_H */
 286