[PATCH] x86: move various CPU initialization objects into .cpuinit.rodata

From: Jan Beulich
Date: Thu Mar 12 2009 - 08:08:54 EST

Impact: debuggability and micro-optimization

Putting whatever is possible into the (final) .rodata section increases
the likelihood of catching memory corruption bugs early, and reduces
false cache line sharing.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>

---
arch/x86/kernel/cpu/addon_cpuid_features.c | 2 +-
arch/x86/kernel/cpu/amd.c | 2 +-
arch/x86/kernel/cpu/centaur.c | 2 +-
arch/x86/kernel/cpu/centaur_64.c | 2 +-
arch/x86/kernel/cpu/common.c | 23 ++++++++++++-----------
arch/x86/kernel/cpu/cpu.h | 11 ++++++-----
arch/x86/kernel/cpu/cyrix.c | 16 ++++++++--------
arch/x86/kernel/cpu/intel.c | 2 +-
arch/x86/kernel/cpu/intel_cacheinfo.c | 8 ++++----
arch/x86/kernel/cpu/transmeta.c | 2 +-
arch/x86/kernel/cpu/umc.c | 2 +-
arch/x86/kernel/mmconf-fam10h_64.c | 2 +-
12 files changed, 38 insertions(+), 36 deletions(-)

--- linux-2.6.29-rc7/arch/x86/kernel/cpu/addon_cpuid_features.c 2009-03-04 09:10:19.000000000 +0100
+++ 2.6.29-rc7-cpuinitconst-x86/arch/x86/kernel/cpu/addon_cpuid_features.c 2009-02-18 15:34:25.000000000 +0100
@@ -29,7 +29,7 @@ void __cpuinit init_scattered_cpuid_feat
u32 regs[4];
const struct cpuid_bit *cb;

- static const struct cpuid_bit cpuid_bits[] = {
+ static const struct cpuid_bit __cpuinitconst cpuid_bits[] = {
{ X86_FEATURE_IDA, CR_EAX, 1, 0x00000006 },
{ 0, 0, 0, 0 }
};
--- linux-2.6.29-rc7/arch/x86/kernel/cpu/amd.c 2009-03-04 09:10:19.000000000 +0100
+++ 2.6.29-rc7-cpuinitconst-x86/arch/x86/kernel/cpu/amd.c 2009-02-18 15:34:25.000000000 +0100
@@ -452,7 +452,7 @@ static unsigned int __cpuinit amd_size_c
}
#endif

-static struct cpu_dev amd_cpu_dev __cpuinitdata = {
+static const struct cpu_dev __cpuinitconst amd_cpu_dev = {
.c_vendor = "AMD",
.c_ident = { "AuthenticAMD" },
#ifdef CONFIG_X86_32
--- linux-2.6.29-rc7/arch/x86/kernel/cpu/centaur.c 2008-12-25 00:26:37.000000000 +0100
+++ 2.6.29-rc7-cpuinitconst-x86/arch/x86/kernel/cpu/centaur.c 2009-02-18 15:34:25.000000000 +0100
@@ -468,7 +468,7 @@ centaur_size_cache(struct cpuinfo_x86 *c
return size;
}

-static struct cpu_dev centaur_cpu_dev __cpuinitdata = {
+static const struct cpu_dev __cpuinitconst centaur_cpu_dev = {
.c_vendor = "Centaur",
.c_ident = { "CentaurHauls" },
.c_early_init = early_init_centaur,
--- linux-2.6.29-rc7/arch/x86/kernel/cpu/centaur_64.c 2008-12-25 00:26:37.000000000 +0100
+++ 2.6.29-rc7-cpuinitconst-x86/arch/x86/kernel/cpu/centaur_64.c 2009-02-18 15:34:25.000000000 +0100
@@ -25,7 +25,7 @@ static void __cpuinit init_centaur(struc
set_cpu_cap(c, X86_FEATURE_LFENCE_RDTSC);
}

-static struct cpu_dev centaur_cpu_dev __cpuinitdata = {
+static const struct cpu_dev centaur_cpu_dev __cpuinitconst = {
.c_vendor = "Centaur",
.c_ident = { "CentaurHauls" },
.c_early_init = early_init_centaur,
--- linux-2.6.29-rc7/arch/x86/kernel/cpu/common.c 2009-03-04 09:10:19.000000000 +0100
+++ 2.6.29-rc7-cpuinitconst-x86/arch/x86/kernel/cpu/common.c 2009-02-18 15:35:09.000000000 +0100
@@ -60,7 +60,7 @@ cpumask_t cpu_sibling_setup_map;
#endif /* CONFIG_X86_32 */


-static struct cpu_dev *this_cpu __cpuinitdata;
+static const struct cpu_dev *this_cpu __cpuinitdata;

#ifdef CONFIG_X86_64
/* We need valid kernel segments for data and code in long mode too
@@ -220,9 +220,9 @@ static inline void squash_the_stupid_ser
*/

/* Look up CPU names by table lookup. */
-static char __cpuinit *table_lookup_model(struct cpuinfo_x86 *c)
+static const char *__cpuinit table_lookup_model(struct cpuinfo_x86 *c)
{
- struct cpu_model_info *info;
+ const struct cpu_model_info *info;

if (c->x86_model >= 16)
return NULL; /* Range check */
@@ -256,7 +256,7 @@ void switch_to_new_gdt(void)
#endif
}

-static struct cpu_dev *cpu_devs[X86_VENDOR_NUM] = {};
+static const struct cpu_dev *__cpuinitdata cpu_devs[X86_VENDOR_NUM] = {};

static void __cpuinit default_init(struct cpuinfo_x86 *c)
{
@@ -275,7 +275,7 @@ static void __cpuinit default_init(struc
#endif
}

-static struct cpu_dev __cpuinitdata default_cpu = {
+static const struct cpu_dev __cpuinitconst default_cpu = {
.c_init = default_init,
.c_vendor = "Unknown",
.c_x86_vendor = X86_VENDOR_UNKNOWN,
@@ -579,12 +579,12 @@ static void __init early_identify_cpu(st

void __init early_cpu_init(void)
{
- struct cpu_dev **cdev;
+ const struct cpu_dev *const *cdev;
int count = 0;

printk("KERNEL supported cpus:\n");
for (cdev = __x86_cpu_dev_start; cdev < __x86_cpu_dev_end; cdev++) {
- struct cpu_dev *cpudev = *cdev;
+ const struct cpu_dev *cpudev = *cdev;
unsigned int j;

if (count >= X86_VENDOR_NUM)
@@ -710,7 +710,7 @@ static void __cpuinit identify_cpu(struc

/* If the model name is still unset, do table lookup. */
if (!c->x86_model_id[0]) {
- char *p;
+ const char *p;
p = table_lookup_model(c);
if (p)
strcpy(c->x86_model_id, p);
@@ -789,7 +789,7 @@ struct msr_range {
unsigned max;
};

-static struct msr_range msr_range_array[] __cpuinitdata = {
+static const struct msr_range msr_range_array[] __cpuinitconst = {
{ 0x00000000, 0x00000418},
{ 0xc0000000, 0xc000040b},
{ 0xc0010000, 0xc0010142},
@@ -836,7 +836,7 @@ __setup("noclflush", setup_noclflush);

void __cpuinit print_cpu_info(struct cpuinfo_x86 *c)
{
- char *vendor = NULL;
+ const char *vendor = NULL;

if (c->x86_vendor < X86_VENDOR_NUM)
vendor = this_cpu->c_vendor;
--- linux-2.6.29-rc7/arch/x86/kernel/cpu/cpu.h 2008-12-25 00:26:37.000000000 +0100
+++ 2.6.29-rc7-cpuinitconst-x86/arch/x86/kernel/cpu/cpu.h 2009-02-18 15:34:25.000000000 +0100
@@ -5,15 +5,15 @@
struct cpu_model_info {
int vendor;
int family;
- char *model_names[16];
+ const char *model_names[16];
};

/* attempt to consolidate cpu attributes */
struct cpu_dev {
- char * c_vendor;
+ const char * c_vendor;

/* some have two possibilities for cpuid string */
- char * c_ident[2];
+ const char * c_ident[2];

struct cpu_model_info c_models[4];

@@ -25,11 +25,12 @@ struct cpu_dev {
};

#define cpu_dev_register(cpu_devX) \
- static struct cpu_dev *__cpu_dev_##cpu_devX __used \
+ static const struct cpu_dev *const __cpu_dev_##cpu_devX __used \
__attribute__((__section__(".x86_cpu_dev.init"))) = \
&cpu_devX;

-extern struct cpu_dev *__x86_cpu_dev_start[], *__x86_cpu_dev_end[];
+extern const struct cpu_dev *const __x86_cpu_dev_start[],
+ *const __x86_cpu_dev_end[];

extern void display_cacheinfo(struct cpuinfo_x86 *c);

--- linux-2.6.29-rc7/arch/x86/kernel/cpu/cyrix.c 2008-12-25 00:26:37.000000000 +0100
+++ 2.6.29-rc7-cpuinitconst-x86/arch/x86/kernel/cpu/cyrix.c 2009-02-18 15:34:25.000000000 +0100
@@ -61,23 +61,23 @@ static void __cpuinit do_cyrix_devid(uns
*/
static unsigned char Cx86_dir0_msb __cpuinitdata = 0;

-static char Cx86_model[][9] __cpuinitdata = {
+static const char __cpuinitconst Cx86_model[][9] = {
"Cx486", "Cx486", "5x86 ", "6x86", "MediaGX ", "6x86MX ",
"M II ", "Unknown"
};
-static char Cx486_name[][5] __cpuinitdata = {
+static const char __cpuinitconst Cx486_name[][5] = {
"SLC", "DLC", "SLC2", "DLC2", "SRx", "DRx",
"SRx2", "DRx2"
};
-static char Cx486S_name[][4] __cpuinitdata = {
+static const char __cpuinitconst Cx486S_name[][4] = {
"S", "S2", "Se", "S2e"
};
-static char Cx486D_name[][4] __cpuinitdata = {
+static const char __cpuinitconst Cx486D_name[][4] = {
"DX", "DX2", "?", "?", "?", "DX4"
};
static char Cx86_cb[] __cpuinitdata = "?.5x Core/Bus Clock";
-static char cyrix_model_mult1[] __cpuinitdata = "12??43";
-static char cyrix_model_mult2[] __cpuinitdata = "12233445";
+static const char __cpuinitconst cyrix_model_mult1[] = "12??43";
+static const char __cpuinitconst cyrix_model_mult2[] = "12233445";

/*
* Reset the slow-loop (SLOP) bit on the 686(L) which is set by some old
@@ -435,7 +435,7 @@ static void __cpuinit cyrix_identify(str
}
}

-static struct cpu_dev cyrix_cpu_dev __cpuinitdata = {
+static const struct cpu_dev __cpuinitconst cyrix_cpu_dev = {
.c_vendor = "Cyrix",
.c_ident = { "CyrixInstead" },
.c_early_init = early_init_cyrix,
@@ -446,7 +446,7 @@ static struct cpu_dev cyrix_cpu_dev __cp

cpu_dev_register(cyrix_cpu_dev);

-static struct cpu_dev nsc_cpu_dev __cpuinitdata = {
+static const struct cpu_dev __cpuinitconst nsc_cpu_dev = {
.c_vendor = "NSC",
.c_ident = { "Geode by NSC" },
.c_init = init_nsc,
--- linux-2.6.29-rc7/arch/x86/kernel/cpu/intel.c 2009-03-04 09:10:19.000000000 +0100
+++ 2.6.29-rc7-cpuinitconst-x86/arch/x86/kernel/cpu/intel.c 2009-02-18 15:34:25.000000000 +0100
@@ -374,7 +374,7 @@ static unsigned int __cpuinit intel_size
}
#endif

-static struct cpu_dev intel_cpu_dev __cpuinitdata = {
+static const struct cpu_dev __cpuinitconst intel_cpu_dev = {
.c_vendor = "Intel",
.c_ident = { "GenuineIntel" },
#ifdef CONFIG_X86_32
--- linux-2.6.29-rc7/arch/x86/kernel/cpu/intel_cacheinfo.c 2009-03-04 09:10:19.000000000 +0100
+++ 2.6.29-rc7-cpuinitconst-x86/arch/x86/kernel/cpu/intel_cacheinfo.c 2009-02-18 15:34:25.000000000 +0100
@@ -32,7 +32,7 @@ struct _cache_table
};

/* all the cache descriptor types we care about (no TLB or trace cache entries) */
-static struct _cache_table cache_table[] __cpuinitdata =
+static const struct _cache_table __cpuinitconst cache_table[] =
{
{ 0x06, LVL_1_INST, 8 }, /* 4-way set assoc, 32 byte line size */
{ 0x08, LVL_1_INST, 16 }, /* 4-way set assoc, 32 byte line size */
@@ -197,15 +197,15 @@ union l3_cache {
unsigned val;
};

-static unsigned short assocs[] __cpuinitdata = {
+static const unsigned short __cpuinitconst assocs[] = {
[1] = 1, [2] = 2, [4] = 4, [6] = 8,
[8] = 16, [0xa] = 32, [0xb] = 48,
[0xc] = 64,
[0xf] = 0xffff // ??
};

-static unsigned char levels[] __cpuinitdata = { 1, 1, 2, 3 };
-static unsigned char types[] __cpuinitdata = { 1, 2, 3, 3 };
+static const unsigned char __cpuinitconst levels[] = { 1, 1, 2, 3 };
+static const unsigned char __cpuinitconst types[] = { 1, 2, 3, 3 };

static void __cpuinit
amd_cpuid4(int leaf, union _cpuid4_leaf_eax *eax,
--- linux-2.6.29-rc7/arch/x86/kernel/cpu/transmeta.c 2008-12-25 00:26:37.000000000 +0100
+++ 2.6.29-rc7-cpuinitconst-x86/arch/x86/kernel/cpu/transmeta.c 2009-02-18 15:34:25.000000000 +0100
@@ -98,7 +98,7 @@ static void __cpuinit init_transmeta(str
#endif
}

-static struct cpu_dev transmeta_cpu_dev __cpuinitdata = {
+static const struct cpu_dev __cpuinitconst transmeta_cpu_dev = {
.c_vendor = "Transmeta",
.c_ident = { "GenuineTMx86", "TransmetaCPU" },
.c_early_init = early_init_transmeta,
--- linux-2.6.29-rc7/arch/x86/kernel/cpu/umc.c 2008-12-25 00:26:37.000000000 +0100
+++ 2.6.29-rc7-cpuinitconst-x86/arch/x86/kernel/cpu/umc.c 2009-02-18 15:34:25.000000000 +0100
@@ -8,7 +8,7 @@
* so no special init takes place.
*/

-static struct cpu_dev umc_cpu_dev __cpuinitdata = {
+static const struct cpu_dev __cpuinitconst umc_cpu_dev = {
.c_vendor = "UMC",
.c_ident = { "UMC UMC UMC" },
.c_models = {
--- linux-2.6.29-rc7/arch/x86/kernel/mmconf-fam10h_64.c 2009-03-04 09:10:19.000000000 +0100
+++ 2.6.29-rc7-cpuinitconst-x86/arch/x86/kernel/mmconf-fam10h_64.c 2009-02-18 15:34:25.000000000 +0100
@@ -226,7 +226,7 @@ static int __devinit set_check_enable_am
return 0;
}

-static struct dmi_system_id __devinitdata mmconf_dmi_table[] = {
+static const struct dmi_system_id __cpuinitconst mmconf_dmi_table[] = {
{
.callback = set_check_enable_amd_mmconf,
.ident = "Sun Microsystems Machine",


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