arch/x86/include/asm/sync_core.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ASM_X86_SYNC_CORE_H
   3 #define _ASM_X86_SYNC_CORE_H
   4
   5 #include <linux/preempt.h>
   6 #include <asm/processor.h>
   7 #include <asm/cpufeature.h>
   8
   9 /*
  10  * Ensure that a core serializing instruction is issued before returning
  11  * to user-mode. x86 implements return to user-space through sysexit,
  12  * sysrel, and sysretq, which are not core serializing.
  13  */
  14 static inline void sync_core_before_usermode(void)
  15 {
  16         /* With PTI, we unconditionally serialize before running user code. */
  17         if (static_cpu_has(X86_FEATURE_PTI))
  18                 return;
  19         /*
  20          * Return from interrupt and NMI is done through iret, which is core
  21          * serializing.
  22          */
  23         if (in_irq() || in_nmi())
  24                 return;
  25         sync_core();
  26 }
  27
  28 #endif /* _ASM_X86_SYNC_CORE_H */