[PATCH] x86-64: Add option to compile for Core2

Add an option to compile for Intel's Core 2

The Kconfig help is a mouthful due to the inventiveness of Intel's
product naming department.

Mainly for the 64bit cache line sizes because gcc doesn't support
optimizing for core2 yet. However it will and then the kernel
should be ready by passing the right option

Also fix the old MPSC help text to confirm better to reality.
Signed-off-by: Andi Kleen <ak@suse.de>

arch/x86_64/Kconfig

@@ -122,7 +122,7 @@ endchoice
 
 choice
 	prompt "Processor family"
-	default MK8
+	default GENERIC_CPU
 
 config MK8
 	bool "AMD-Opteron/Athlon64"
@@ -130,16 +130,31 @@ config MK8
 	  Optimize for AMD Opteron/Athlon64/Hammer/K8 CPUs.
 
 config MPSC
-       bool "Intel EM64T"
+       bool "Intel P4 / older Netburst based Xeon"
        help
-	  Optimize for Intel Pentium 4 and Xeon CPUs with Intel
-	  Extended Memory 64 Technology(EM64T). For details see
+	  Optimize for Intel Pentium 4 and older Nocona/Dempsey Xeon CPUs
+	  with Intel Extended Memory 64 Technology(EM64T). For details see
 	  <http://www.intel.com/technology/64bitextensions/>.
+	  Note the the latest Xeons (Xeon 51xx and 53xx) are not based on the
+          Netburst core and shouldn't use this option. You can distingush them
+	  using the cpu family field
+	  in /proc/cpuinfo. Family 15 is a older Xeon, Family 6 a newer one
+	  (this rule only applies to system that support EM64T)
+
+config MCORE2
+	bool "Intel Core2 / newer Xeon"
+	help
+	  Optimize for Intel Core2 and newer Xeons (51xx)
+	  You can distingush the newer Xeons from the older ones using
+	  the cpu family field in /proc/cpuinfo. 15 is a older Xeon
+	  (use CONFIG_MPSC then), 6 is a newer one. This rule only
+	  applies to CPUs that support EM64T.
 
 config GENERIC_CPU
 	bool "Generic-x86-64"
 	help
 	  Generic x86-64 CPU.
+	  Run equally well on all x86-64 CPUs.
 
 endchoice
 
@@ -149,12 +164,12 @@ endchoice
 config X86_L1_CACHE_BYTES
 	int
 	default "128" if GENERIC_CPU || MPSC
-	default "64" if MK8
+	default "64" if MK8 || MCORE2
 
 config X86_L1_CACHE_SHIFT
 	int
 	default "7" if GENERIC_CPU || MPSC
-	default "6" if MK8
+	default "6" if MK8 || MCORE2
 
 config X86_INTERNODE_CACHE_BYTES
 	int

arch/x86_64/Makefile

@@ -30,6 +30,10 @@ cflags-y	:=
 cflags-kernel-y	:=
 cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8)
 cflags-$(CONFIG_MPSC) += $(call cc-option,-march=nocona)
+# gcc doesn't support -march=core2 yet as of gcc 4.3, but I hope it
+# will eventually. Use -mtune=generic as fallback
+cflags-$(CONFIG_MCORE2) += \
+	$(call cc-option,-march=core2,$(call cc-option,-mtune=generic))
 cflags-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mtune=generic)
 
 cflags-y += -m64