x86: add specific support for Intel Atom architecture

Add another option when selecting CPU family so the kernel can be
optimized for Intel Atom CPUs. If GCC supports tuning options for
Intel Atom they will be used.

Signed-off-by: Tobias Doerffel <tobias.doerffel@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
LKML-Reference: <1251018457-19157-1-git-send-email-tobias.doerffel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

4 files changed, 20 insertions, 5 deletions

diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu
index 8130334329c0..527519b8a9f9 100644
--- a/arch/x86/Kconfig.cpu
+++ b/arch/x86/Kconfig.cpu
@@ -262,6 +262,15 @@ config MCORE2
           family in /proc/cpuinfo. Newer ones have 6 and older ones 15
           (not a typo)
 
+config MATOM
+        bool "Intel Atom"
+        ---help---
+
+          Select this for the Intel Atom platform. Intel Atom CPUs have an
+          in-order pipelining architecture and thus can benefit from
+          accordingly optimized code. Use a recent GCC with specific Atom
+          support in order to fully benefit from selecting this option.
+
 config GENERIC_CPU
         bool "Generic-x86-64"
         depends on X86_64
@@ -295,7 +304,7 @@ config X86_CPU
 config X86_L1_CACHE_BYTES
         int
         default "128" if MPSC
-        default "64" if GENERIC_CPU || MK8 || MCORE2 || X86_32
+        default "64" if GENERIC_CPU || MK8 || MCORE2 || MATOM || X86_32
 
 config X86_INTERNODE_CACHE_BYTES
         int
@@ -310,7 +319,7 @@ config X86_L1_CACHE_SHIFT
         default "7" if MPENTIUM4 || MPSC
         default "4" if X86_ELAN || M486 || M386 || MGEODEGX1
         default "5" if MWINCHIP3D || MWINCHIPC6 || MCRUSOE || MEFFICEON || MCYRIXIII || MK6 || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || M586 || MVIAC3_2 || MGEODE_LX
-        default "6" if MK7 || MK8 || MPENTIUMM || MCORE2 || MVIAC7 || X86_GENERIC || GENERIC_CPU
+        default "6" if MK7 || MK8 || MPENTIUMM || MCORE2 || MATOM || MVIAC7 || X86_GENERIC || GENERIC_CPU
 
 config X86_XADD
         def_bool y
@@ -359,7 +368,7 @@ config X86_INTEL_USERCOPY
 
 config X86_USE_PPRO_CHECKSUM
         def_bool y
-        depends on MWINCHIP3D || MWINCHIPC6 || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MK8 || MVIAC3_2 || MEFFICEON || MGEODE_LX || MCORE2
+        depends on MWINCHIP3D || MWINCHIPC6 || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MK8 || MVIAC3_2 || MEFFICEON || MGEODE_LX || MCORE2 || MATOM
 
 config X86_USE_3DNOW
         def_bool y
@@ -387,7 +396,7 @@ config X86_P6_NOP
 
 config X86_TSC
         def_bool y
-        depends on ((MWINCHIP3D || MCRUSOE || MEFFICEON || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || MK8 || MVIAC3_2 || MVIAC7 || MGEODEGX1 || MGEODE_LX || MCORE2) && !X86_NUMAQ) || X86_64
+        depends on ((MWINCHIP3D || MCRUSOE || MEFFICEON || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || MK8 || MVIAC3_2 || MVIAC7 || MGEODEGX1 || MGEODE_LX || MCORE2 || MATOM) && !X86_NUMAQ) || X86_64
 
 config X86_CMPXCHG64
         def_bool y
@@ -397,7 +406,7 @@ config X86_CMPXCHG64
 # generates cmov.
 config X86_CMOV
         def_bool y
-        depends on (MK8 || MK7 || MCORE2 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MVIAC3_2 || MVIAC7 || MCRUSOE || MEFFICEON || X86_64)
+        depends on (MK8 || MK7 || MCORE2 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MVIAC3_2 || MVIAC7 || MCRUSOE || MEFFICEON || X86_64 || MATOM)
 
 config X86_MINIMUM_CPU_FAMILY
         int
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 1b68659c41b4..8a4c24c96d08 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -55,6 +55,8 @@ else
 
         cflags-$(CONFIG_MCORE2) += \
                 $(call cc-option,-march=core2,$(call cc-option,-mtune=generic))
+        cflags-$(CONFIG_MATOM) += $(call cc-option,-march=atom) \
+                $(call cc-option,-mtune=atom,$(call cc-option,-mtune=generic))
         cflags-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mtune=generic)
         KBUILD_CFLAGS += $(cflags-y)
 
diff --git a/arch/x86/Makefile_32.cpu b/arch/x86/Makefile_32.cpu
index 80177ec052f0..30e9a264f69d 100644
--- a/arch/x86/Makefile_32.cpu
+++ b/arch/x86/Makefile_32.cpu
@@ -33,6 +33,8 @@ cflags-$(CONFIG_MCYRIXIII)	+= $(call cc-option,-march=c3,-march=i486) $(align)-f
 cflags-$(CONFIG_MVIAC3_2)       += $(call cc-option,-march=c3-2,-march=i686)
 cflags-$(CONFIG_MVIAC7)         += -march=i686
 cflags-$(CONFIG_MCORE2)         += -march=i686 $(call tune,core2)
+cflags-$(CONFIG_MATOM)          += $(call cc-option,-march=atom,$(call cc-option,-march=core2,-march=i686)) \
+        $(call cc-option,-mtune=atom,$(call cc-option,-mtune=generic))
 
 # AMD Elan support
 cflags-$(CONFIG_X86_ELAN)       += -march=i486
diff --git a/arch/x86/include/asm/module.h b/arch/x86/include/asm/module.h
index 47d62743c4d5..e959c4afab59 100644
--- a/arch/x86/include/asm/module.h
+++ b/arch/x86/include/asm/module.h
@@ -28,6 +28,8 @@ struct mod_arch_specific {};
 #define MODULE_PROC_FAMILY "586MMX "
 #elif defined CONFIG_MCORE2
 #define MODULE_PROC_FAMILY "CORE2 "
+#elif defined CONFIG_MATOM
+#define MODULE_PROC_FAMILY "ATOM "
 #elif defined CONFIG_M686
 #define MODULE_PROC_FAMILY "686 "
 #elif defined CONFIG_MPENTIUMII