1 files changed, 35 insertions, 0 deletions
diff --git a/arch/x86/include/asm/fpu/xcr.h b/arch/x86/include/asm/fpu/xcr.h
new file mode 100644
index 000000000..9a710c060
--- /dev/null
+++ b/arch/x86/include/asm/fpu/xcr.h
@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_FPU_XCR_H
+#define _ASM_X86_FPU_XCR_H
+
+#define XCR_XFEATURE_ENABLED_MASK	0x00000000
+#define XCR_XFEATURE_IN_USE_MASK	0x00000001
+
+static __always_inline u64 xgetbv(u32 index)
+{
+	u32 eax, edx;
+
+	asm volatile("xgetbv" : "=a" (eax), "=d" (edx) : "c" (index));
+	return eax + ((u64)edx << 32);
+}
+
+static inline void xsetbv(u32 index, u64 value)
+{
+	u32 eax = value;
+	u32 edx = value >> 32;
+
+	asm volatile("xsetbv" :: "a" (eax), "d" (edx), "c" (index));
+}
+
+/*
+ * Return a mask of xfeatures which are currently being tracked
+ * by the processor as being in the initial configuration.
+ *
+ * Callers should check X86_FEATURE_XGETBV1.
+ */
+static __always_inline u64 xfeatures_in_use(void)
+{
+	return xgetbv(XCR_XFEATURE_IN_USE_MASK);
+}
+
+#endif /* _ASM_X86_FPU_XCR_H */