x86/cpu: Track legacy CPU model data only on 32-bit kernels

struct cpu_dev's c_models is only ever set inside CONFIG_X86_32
conditionals (or code that's being built for 32-bit only), so
there's no use of reserving the (empty) space for the model
names in a 64-bit kernel.

Similarly, c_size_cache is only used in the #else of a
CONFIG_X86_64 conditional, so reserving space for (and in one
case even initializing) that field is pointless for 64-bit
kernels too.

While moving both fields to the end of the structure, I also
noticed that:

 - the c_models array size was one too small, potentially causing
   table_lookup_model() to return garbage on Intel CPUs (intel.c's
   instance was lacking the sentinel with family being zero), so the
   patch bumps that by one,

 - c_models' vendor sub-field was unused (and anyway redundant
   with the base structure's c_x86_vendor field), so the patch deletes it.

Also rename the legacy fields so that their legacy nature stands out
and comment their declarations.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Link: http://lkml.kernel.org/r/5265036802000078000FC4DB@nat28.tlf.novell.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 11 insertions, 9 deletions

diff --git a/arch/x86/kernel/cpu/cpu.h b/arch/x86/kernel/cpu/cpu.h
index 4041c24ae7db..c37dc37e8317 100644
--- a/arch/x86/kernel/cpu/cpu.h
+++ b/arch/x86/kernel/cpu/cpu.h
@@ -1,12 +1,6 @@
 #ifndef ARCH_X86_CPU_H
 #define ARCH_X86_CPU_H
 
-struct cpu_model_info {
-	int		vendor;
-	int		family;
-	const char	*model_names[16];
-};
-
 /* attempt to consolidate cpu attributes */
 struct cpu_dev {
 	const char	*c_vendor;
@@ -14,15 +8,23 @@ struct cpu_dev {
 	/* some have two possibilities for cpuid string */
 	const char	*c_ident[2];
 
-	struct		cpu_model_info c_models[4];
-
 	void            (*c_early_init)(struct cpuinfo_x86 *);
 	void		(*c_bsp_init)(struct cpuinfo_x86 *);
 	void		(*c_init)(struct cpuinfo_x86 *);
 	void		(*c_identify)(struct cpuinfo_x86 *);
 	void		(*c_detect_tlb)(struct cpuinfo_x86 *);
-	unsigned int	(*c_size_cache)(struct cpuinfo_x86 *, unsigned int);
 	int		c_x86_vendor;
+#ifdef CONFIG_X86_32
+	/* Optional vendor specific routine to obtain the cache size. */
+	unsigned int	(*legacy_cache_size)(struct cpuinfo_x86 *,
+					     unsigned int);
+
+	/* Family/stepping-based lookup table for model names. */
+	struct legacy_cpu_model_info {
+		int		family;
+		const char	*model_names[16];
+	}		legacy_models[5];
+#endif
 };
 
 struct _tlb_table {