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>

6 files changed, 34 insertions, 28 deletions

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 903a264af981..3daece79a142 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -823,8 +823,8 @@ static const struct cpu_dev amd_cpu_dev = {
         .c_vendor       = "AMD",
         .c_ident        = { "AuthenticAMD" },
 #ifdef CONFIG_X86_32
-        .c_models = {
-                { .vendor = X86_VENDOR_AMD, .family = 4, .model_names =
+        .legacy_models = {
+                { .family = 4, .model_names =
                   {
                           [3] = "486 DX/2",
                           [7] = "486 DX/2-WB",
@@ -835,7 +835,7 @@ static const struct cpu_dev amd_cpu_dev = {
                   }
                 },
         },
-        .c_size_cache   = amd_size_cache,
+        .legacy_cache_size = amd_size_cache,
 #endif
         .c_early_init   = early_init_amd,
         .c_detect_tlb   = cpu_detect_tlb_amd,
diff --git a/arch/x86/kernel/cpu/centaur.c b/arch/x86/kernel/cpu/centaur.c
index fbf6c3bc2400..8d5652dc99dd 100644
--- a/arch/x86/kernel/cpu/centaur.c
+++ b/arch/x86/kernel/cpu/centaur.c
@@ -468,10 +468,10 @@ static void init_centaur(struct cpuinfo_x86 *c)
 #endif
 }
 
+#ifdef CONFIG_X86_32
 static unsigned int
 centaur_size_cache(struct cpuinfo_x86 *c, unsigned int size)
 {
-#ifdef CONFIG_X86_32
         /* VIA C3 CPUs (670-68F) need further shifting. */
         if ((c->x86 == 6) && ((c->x86_model == 7) || (c->x86_model == 8)))
                 size >>= 8;
@@ -484,16 +484,18 @@ centaur_size_cache(struct cpuinfo_x86 *c, unsigned int size)
         if ((c->x86 == 6) && (c->x86_model == 9) &&
                                 (c->x86_mask == 1) && (size == 65))
                 size -= 1;
-#endif
         return size;
 }
+#endif
 
 static const struct cpu_dev centaur_cpu_dev = {
         .c_vendor       = "Centaur",
         .c_ident        = { "CentaurHauls" },
         .c_early_init   = early_init_centaur,
         .c_init         = init_centaur,
-        .c_size_cache   = centaur_size_cache,
+#ifdef CONFIG_X86_32
+        .legacy_cache_size = centaur_size_cache,
+#endif
         .c_x86_vendor   = X86_VENDOR_CENTAUR,
 };
 
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 2793d1f095a2..9ada0b37ae07 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -346,7 +346,8 @@ static void filter_cpuid_features(struct cpuinfo_x86 *c, bool warn)
 /* Look up CPU names by table lookup. */
 static const char *table_lookup_model(struct cpuinfo_x86 *c)
 {
-        const struct cpu_model_info *info;
+#ifdef CONFIG_X86_32
+        const struct legacy_cpu_model_info *info;
 
         if (c->x86_model >= 16)
                 return NULL;    /* Range check */
@@ -354,13 +355,14 @@ static const char *table_lookup_model(struct cpuinfo_x86 *c)
         if (!this_cpu)
                 return NULL;
 
-        info = this_cpu->c_models;
+        info = this_cpu->legacy_models;
 
-        while (info && info->family) {
+        while (info->family) {
                 if (info->family == c->x86)
                         return info->model_names[c->x86_model];
                 info++;
         }
+#endif
         return NULL;            /* Not found */
 }
 
@@ -450,8 +452,8 @@ void cpu_detect_cache_sizes(struct cpuinfo_x86 *c)
         c->x86_tlbsize += ((ebx >> 16) & 0xfff) + (ebx & 0xfff);
 #else
         /* do processor-specific cache resizing */
-        if (this_cpu->c_size_cache)
-                l2size = this_cpu->c_size_cache(c, l2size);
+        if (this_cpu->legacy_cache_size)
+                l2size = this_cpu->legacy_cache_size(c, l2size);
 
         /* Allow user to override all this if necessary. */
         if (cachesize_override != -1)
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 {
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index ec7299566f79..dc1ec0dff939 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -665,8 +665,8 @@ static const struct cpu_dev intel_cpu_dev = {
         .c_vendor       = "Intel",
         .c_ident        = { "GenuineIntel" },
 #ifdef CONFIG_X86_32
-        .c_models = {
-                { .vendor = X86_VENDOR_INTEL, .family = 4, .model_names =
+        .legacy_models = {
+                { .family = 4, .model_names =
                   {
                           [0] = "486 DX-25/33",
                           [1] = "486 DX-50",
@@ -679,7 +679,7 @@ static const struct cpu_dev intel_cpu_dev = {
                           [9] = "486 DX/4-WB"
                   }
                 },
-                { .vendor = X86_VENDOR_INTEL, .family = 5, .model_names =
+                { .family = 5, .model_names =
                   {
                           [0] = "Pentium 60/66 A-step",
                           [1] = "Pentium 60/66",
@@ -690,7 +690,7 @@ static const struct cpu_dev intel_cpu_dev = {
                           [8] = "Mobile Pentium MMX"
                   }
                 },
-                { .vendor = X86_VENDOR_INTEL, .family = 6, .model_names =
+                { .family = 6, .model_names =
                   {
                           [0] = "Pentium Pro A-step",
                           [1] = "Pentium Pro",
@@ -704,7 +704,7 @@ static const struct cpu_dev intel_cpu_dev = {
                           [11] = "Pentium III (Tualatin)",
                   }
                 },
-                { .vendor = X86_VENDOR_INTEL, .family = 15, .model_names =
+                { .family = 15, .model_names =
                   {
                           [0] = "Pentium 4 (Unknown)",
                           [1] = "Pentium 4 (Willamette)",
@@ -714,7 +714,7 @@ static const struct cpu_dev intel_cpu_dev = {
                   }
                 },
         },
-        .c_size_cache   = intel_size_cache,
+        .legacy_cache_size = intel_size_cache,
 #endif
         .c_detect_tlb   = intel_detect_tlb,
         .c_early_init   = early_init_intel,
diff --git a/arch/x86/kernel/cpu/umc.c b/arch/x86/kernel/cpu/umc.c
index 202759a14121..75c5ad5d35cc 100644
--- a/arch/x86/kernel/cpu/umc.c
+++ b/arch/x86/kernel/cpu/umc.c
@@ -11,8 +11,8 @@
 static const struct cpu_dev umc_cpu_dev = {
         .c_vendor       = "UMC",
         .c_ident        = { "UMC UMC UMC" },
-        .c_models = {
-                { .vendor = X86_VENDOR_UMC, .family = 4, .model_names =
+        .legacy_models  = {
+                { .family = 4, .model_names =
                   {
                           [1] = "U5D",
                           [2] = "U5S",