x86: add NOPL as a synthetic CPU feature bit
The long noops ("NOPL") are supposed to be detected by family >= 6.
Unfortunately, several non-Intel x86 implementations, both hardware
and software, don't obey this dictum. Instead, probe for NOPL
directly by executing a NOPL instruction and see if we get #UD.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
diff --git a/include/asm-x86/required-features.h b/include/asm-x86/required-features.h
index adec887..5c2ff4b 100644
--- a/include/asm-x86/required-features.h
+++ b/include/asm-x86/required-features.h
@@ -41,6 +41,12 @@
# define NEED_3DNOW 0
#endif
+#if defined(CONFIG_X86_P6_NOP) || defined(CONFIG_X86_64)
+# define NEED_NOPL (1<<(X86_FEATURE_NOPL & 31))
+#else
+# define NEED_NOPL 0
+#endif
+
#ifdef CONFIG_X86_64
#define NEED_PSE 0
#define NEED_MSR (1<<(X86_FEATURE_MSR & 31))
@@ -67,7 +73,7 @@
#define REQUIRED_MASK1 (NEED_LM|NEED_3DNOW)
#define REQUIRED_MASK2 0
-#define REQUIRED_MASK3 0
+#define REQUIRED_MASK3 (NEED_NOPL)
#define REQUIRED_MASK4 0
#define REQUIRED_MASK5 0
#define REQUIRED_MASK6 0