arch/x86/include/asm/xcr.h

   1 /* -*- linux-c -*- ------------------------------------------------------- *
   2  *
   3  *   Copyright 2008 rPath, Inc. - All Rights Reserved
   4  *
   5  *   This file is part of the Linux kernel, and is made available under
   6  *   the terms of the GNU General Public License version 2 or (at your
   7  *   option) any later version; incorporated herein by reference.
   8  *
   9  * ----------------------------------------------------------------------- */
  10
  11 /*
  12  * asm-x86/xcr.h
  13  *
  14  * Definitions for the eXtended Control Register instructions
  15  */
  16
  17 #ifndef _ASM_X86_XCR_H
  18 #define _ASM_X86_XCR_H
  19
  20 #define XCR_XFEATURE_ENABLED_MASK       0x00000000
  21
  22 #ifdef __KERNEL__
  23 # ifndef __ASSEMBLY__
  24
  25 #include <linux/types.h>
  26
  27 static inline u64 xgetbv(u32 index)
  28 {
  29         u32 eax, edx;
  30
  31         asm volatile(".byte 0x0f,0x01,0xd0" /* xgetbv */
  32                      : "=a" (eax), "=d" (edx)
  33                      : "c" (index));
  34         return eax + ((u64)edx << 32);
  35 }
  36
  37 static inline void xsetbv(u32 index, u64 value)
  38 {
  39         u32 eax = value;
  40         u32 edx = value >> 32;
  41
  42         asm volatile(".byte 0x0f,0x01,0xd1" /* xsetbv */
  43                      : : "a" (eax), "d" (edx), "c" (index));
  44 }
  45
  46 # endif /* __ASSEMBLY__ */
  47 #endif /* __KERNEL__ */
  48
  49 #endif /* _ASM_X86_XCR_H */