arch/x86/include/asm/current.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ASM_X86_CURRENT_H
   3 #define _ASM_X86_CURRENT_H
   4
   5 #include <linux/build_bug.h>
   6 #include <linux/compiler.h>
   7
   8 #ifndef __ASSEMBLY__
   9
  10 #include <linux/cache.h>
  11 #include <asm/percpu.h>
  12
  13 struct task_struct;
  14
  15 struct pcpu_hot {
  16         union {
  17                 struct {
  18                         struct task_struct      *current_task;
  19                         int                     preempt_count;
  20                         int                     cpu_number;
  21 #ifdef CONFIG_CALL_DEPTH_TRACKING
  22                         u64                     call_depth;
  23 #endif
  24                         unsigned long           top_of_stack;
  25                         void                    *hardirq_stack_ptr;
  26                         u16                     softirq_pending;
  27 #ifdef CONFIG_X86_64
  28                         bool                    hardirq_stack_inuse;
  29 #else
  30                         void                    *softirq_stack_ptr;
  31 #endif
  32                 };
  33                 u8      pad[64];
  34         };
  35 };
  36 static_assert(sizeof(struct pcpu_hot) == 64);
  37
  38 DECLARE_PER_CPU_ALIGNED(struct pcpu_hot, pcpu_hot);
  39
  40 /* const-qualified alias to pcpu_hot, aliased by linker. */
  41 DECLARE_PER_CPU_ALIGNED(const struct pcpu_hot __percpu_seg_override,
  42                         const_pcpu_hot);
  43
  44 static __always_inline struct task_struct *get_current(void)
  45 {
  46         if (IS_ENABLED(CONFIG_USE_X86_SEG_SUPPORT))
  47                 return this_cpu_read_const(const_pcpu_hot.current_task);
  48
  49         return this_cpu_read_stable(pcpu_hot.current_task);
  50 }
  51
  52 #define current get_current()
  53
  54 #endif /* __ASSEMBLY__ */
  55
  56 #endif /* _ASM_X86_CURRENT_H */