X-Git-Url: http://git.cascardo.info/?a=blobdiff_plain;f=arch%2Fx86%2Finclude%2Fasm%2Fspecial_insns.h;h=aee6e76e561ec0cd24cfe1f92f4dc9cf6e24ece4;hb=a927cb83f3300bcb1ae18672e58029acddd18b33;hp=2270e41b32fd856e226840d4f76dddaa7852d13d;hpb=dbe08116b87cdc2217f11a78b5b70e29068b7efd;p=cascardo%2Flinux.git

diff --git a/arch/x86/include/asm/special_insns.h b/arch/x86/include/asm/special_insns.h
index 2270e41b32fd..aee6e76e561e 100644
--- a/arch/x86/include/asm/special_insns.h
+++ b/arch/x86/include/asm/special_insns.h
@@ -98,6 +98,28 @@ static inline void native_write_cr8(unsigned long val)
 }
 #endif
 
+#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
+static inline u32 __read_pkru(void)
+{
+	u32 ecx = 0;
+	u32 edx, pkru;
+
+	/*
+	 * "rdpkru" instruction.  Places PKRU contents in to EAX,
+	 * clears EDX and requires that ecx=0.
+	 */
+	asm volatile(".byte 0x0f,0x01,0xee\n\t"
+		     : "=a" (pkru), "=d" (edx)
+		     : "c" (ecx));
+	return pkru;
+}
+#else
+static inline u32 __read_pkru(void)
+{
+	return 0;
+}
+#endif
+
 static inline void native_wbinvd(void)
 {
 	asm volatile("wbinvd": : :"memory");