7 files changed, 162 insertions, 60 deletions

diff --git a/arch/i386/kernel/cpu/mtrr/amd.c b/arch/i386/kernel/cpu/mtrr/amd.c
index 1a1e04b6fd00..0949cdbf848a 100644
--- a/arch/i386/kernel/cpu/mtrr/amd.c
+++ b/arch/i386/kernel/cpu/mtrr/amd.c
@@ -7,7 +7,7 @@
 
 static void
 amd_get_mtrr(unsigned int reg, unsigned long *base,
-             unsigned int *size, mtrr_type * type)
+             unsigned long *size, mtrr_type * type)
 {
         unsigned long low, high;
 
diff --git a/arch/i386/kernel/cpu/mtrr/centaur.c b/arch/i386/kernel/cpu/mtrr/centaur.c
index 33f00ac314ef..cb9aa3a7a7ab 100644
--- a/arch/i386/kernel/cpu/mtrr/centaur.c
+++ b/arch/i386/kernel/cpu/mtrr/centaur.c
@@ -17,7 +17,7 @@ static u8 centaur_mcr_type;	/* 0 for winchip, 1 for winchip2 */
  */
 
 static int
-centaur_get_free_region(unsigned long base, unsigned long size)
+centaur_get_free_region(unsigned long base, unsigned long size, int replace_reg)
 /*  [SUMMARY] Get a free MTRR.
     <base> The starting (base) address of the region.
     <size> The size (in bytes) of the region.
@@ -26,10 +26,11 @@ centaur_get_free_region(unsigned long base, unsigned long size)
 {
         int i, max;
         mtrr_type ltype;
-        unsigned long lbase;
-        unsigned int lsize;
+        unsigned long lbase, lsize;
 
         max = num_var_ranges;
+        if (replace_reg >= 0 && replace_reg < max)
+                return replace_reg;
         for (i = 0; i < max; ++i) {
                 if (centaur_mcr_reserved & (1 << i))
                         continue;
@@ -49,7 +50,7 @@ mtrr_centaur_report_mcr(int mcr, u32 lo, u32 hi)
 
 static void
 centaur_get_mcr(unsigned int reg, unsigned long *base,
-                unsigned int *size, mtrr_type * type)
+                unsigned long *size, mtrr_type * type)
 {
         *base = centaur_mcr[reg].high >> PAGE_SHIFT;
         *size = -(centaur_mcr[reg].low & 0xfffff000) >> PAGE_SHIFT;
diff --git a/arch/i386/kernel/cpu/mtrr/cyrix.c b/arch/i386/kernel/cpu/mtrr/cyrix.c
index 9027a987006b..0737a596db43 100644
--- a/arch/i386/kernel/cpu/mtrr/cyrix.c
+++ b/arch/i386/kernel/cpu/mtrr/cyrix.c
@@ -9,7 +9,7 @@ int arr3_protected;
 
 static void
 cyrix_get_arr(unsigned int reg, unsigned long *base,
-              unsigned int *size, mtrr_type * type)
+              unsigned long *size, mtrr_type * type)
 {
         unsigned long flags;
         unsigned char arr, ccr3, rcr, shift;
@@ -77,7 +77,7 @@ cyrix_get_arr(unsigned int reg, unsigned long *base,
 }
 
 static int
-cyrix_get_free_region(unsigned long base, unsigned long size)
+cyrix_get_free_region(unsigned long base, unsigned long size, int replace_reg)
 /*  [SUMMARY] Get a free ARR.
     <base> The starting (base) address of the region.
     <size> The size (in bytes) of the region.
@@ -86,9 +86,24 @@ cyrix_get_free_region(unsigned long base, unsigned long size)
 {
         int i;
         mtrr_type ltype;
-        unsigned long lbase;
-        unsigned int  lsize;
+        unsigned long lbase, lsize;
 
+        switch (replace_reg) {
+        case 7:
+                if (size < 0x40)
+                        break;
+        case 6:
+        case 5:
+        case 4:
+                return replace_reg;
+        case 3:
+                if (arr3_protected)
+                        break;
+        case 2:
+        case 1:
+        case 0:
+                return replace_reg;
+        }
         /* If we are to set up a region >32M then look at ARR7 immediately */
         if (size > 0x2000) {
                 cyrix_get_arr(7, &lbase, &lsize, &ltype);
@@ -214,7 +229,7 @@ static void cyrix_set_arr(unsigned int reg, unsigned long base,
 
 typedef struct {
         unsigned long base;
-        unsigned int size;
+        unsigned long size;
         mtrr_type type;
 } arr_state_t;
 
diff --git a/arch/i386/kernel/cpu/mtrr/generic.c b/arch/i386/kernel/cpu/mtrr/generic.c
index ee8dc6753953..f77fc53db654 100644
--- a/arch/i386/kernel/cpu/mtrr/generic.c
+++ b/arch/i386/kernel/cpu/mtrr/generic.c
@@ -3,6 +3,7 @@
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/mm.h>
+#include <linux/module.h>
 #include <asm/io.h>
 #include <asm/mtrr.h>
 #include <asm/msr.h>
@@ -15,12 +16,19 @@ struct mtrr_state {
         struct mtrr_var_range *var_ranges;
         mtrr_type fixed_ranges[NUM_FIXED_RANGES];
         unsigned char enabled;
+        unsigned char have_fixed;
         mtrr_type def_type;
 };
 
 static unsigned long smp_changes_mask;
 static struct mtrr_state mtrr_state = {};
 
+#undef MODULE_PARAM_PREFIX
+#define MODULE_PARAM_PREFIX "mtrr."
+
+static __initdata int mtrr_show;
+module_param_named(show, mtrr_show, bool, 0);
+
 /*  Get the MSR pair relating to a var range  */
 static void __init
 get_mtrr_var_range(unsigned int index, struct mtrr_var_range *vr)
@@ -43,6 +51,14 @@ get_fixed_ranges(mtrr_type * frs)
                 rdmsr(MTRRfix4K_C0000_MSR + i, p[6 + i * 2], p[7 + i * 2]);
 }
 
+static void __init print_fixed(unsigned base, unsigned step, const mtrr_type*types)
+{
+        unsigned i;
+
+        for (i = 0; i < 8; ++i, ++types, base += step)
+                printk(KERN_INFO "MTRR %05X-%05X %s\n", base, base + step - 1, mtrr_attrib_to_str(*types));
+}
+
 /*  Grab all of the MTRR state for this CPU into *state  */
 void __init get_mtrr_state(void)
 {
@@ -58,13 +74,49 @@ void __init get_mtrr_state(void)
         } 
         vrs = mtrr_state.var_ranges;
 
+        rdmsr(MTRRcap_MSR, lo, dummy);
+        mtrr_state.have_fixed = (lo >> 8) & 1;
+
         for (i = 0; i < num_var_ranges; i++)
                 get_mtrr_var_range(i, &vrs[i]);
-        get_fixed_ranges(mtrr_state.fixed_ranges);
+        if (mtrr_state.have_fixed)
+                get_fixed_ranges(mtrr_state.fixed_ranges);
 
         rdmsr(MTRRdefType_MSR, lo, dummy);
         mtrr_state.def_type = (lo & 0xff);
         mtrr_state.enabled = (lo & 0xc00) >> 10;
+
+        if (mtrr_show) {
+                int high_width;
+
+                printk(KERN_INFO "MTRR default type: %s\n", mtrr_attrib_to_str(mtrr_state.def_type));
+                if (mtrr_state.have_fixed) {
+                        printk(KERN_INFO "MTRR fixed ranges %sabled:\n",
+                               mtrr_state.enabled & 1 ? "en" : "dis");
+                        print_fixed(0x00000, 0x10000, mtrr_state.fixed_ranges + 0);
+                        for (i = 0; i < 2; ++i)
+                                print_fixed(0x80000 + i * 0x20000, 0x04000, mtrr_state.fixed_ranges + (i + 1) * 8);
+                        for (i = 0; i < 8; ++i)
+                                print_fixed(0xC0000 + i * 0x08000, 0x01000, mtrr_state.fixed_ranges + (i + 3) * 8);
+                }
+                printk(KERN_INFO "MTRR variable ranges %sabled:\n",
+                       mtrr_state.enabled & 2 ? "en" : "dis");
+                high_width = ((size_or_mask ? ffs(size_or_mask) - 1 : 32) - (32 - PAGE_SHIFT) + 3) / 4;
+                for (i = 0; i < num_var_ranges; ++i) {
+                        if (mtrr_state.var_ranges[i].mask_lo & (1 << 11))
+                                printk(KERN_INFO "MTRR %u base %0*X%05X000 mask %0*X%05X000 %s\n",
+                                       i,
+                                       high_width,
+                                       mtrr_state.var_ranges[i].base_hi,
+                                       mtrr_state.var_ranges[i].base_lo >> 12,
+                                       high_width,
+                                       mtrr_state.var_ranges[i].mask_hi,
+                                       mtrr_state.var_ranges[i].mask_lo >> 12,
+                                       mtrr_attrib_to_str(mtrr_state.var_ranges[i].base_lo & 0xff));
+                        else
+                                printk(KERN_INFO "MTRR %u disabled\n", i);
+                }
+        }
 }
 
 /*  Some BIOS's are fucked and don't set all MTRRs the same!  */
@@ -95,7 +147,7 @@ void mtrr_wrmsr(unsigned msr, unsigned a, unsigned b)
                         smp_processor_id(), msr, a, b);
 }
 
-int generic_get_free_region(unsigned long base, unsigned long size)
+int generic_get_free_region(unsigned long base, unsigned long size, int replace_reg)
 /*  [SUMMARY] Get a free MTRR.
     <base> The starting (base) address of the region.
     <size> The size (in bytes) of the region.
@@ -104,10 +156,11 @@ int generic_get_free_region(unsigned long base, unsigned long size)
 {
         int i, max;
         mtrr_type ltype;
-        unsigned long lbase;
-        unsigned lsize;
+        unsigned long lbase, lsize;
 
         max = num_var_ranges;
+        if (replace_reg >= 0 && replace_reg < max)
+                return replace_reg;
         for (i = 0; i < max; ++i) {
                 mtrr_if->get(i, &lbase, &lsize, &ltype);
                 if (lsize == 0)
@@ -117,7 +170,7 @@ int generic_get_free_region(unsigned long base, unsigned long size)
 }
 
 static void generic_get_mtrr(unsigned int reg, unsigned long *base,
-                             unsigned int *size, mtrr_type * type)
+                             unsigned long *size, mtrr_type *type)
 {
         unsigned int mask_lo, mask_hi, base_lo, base_hi;
 
@@ -202,7 +255,9 @@ static int set_mtrr_var_ranges(unsigned int index, struct mtrr_var_range *vr)
         return changed;
 }
 
-static unsigned long set_mtrr_state(u32 deftype_lo, u32 deftype_hi)
+static u32 deftype_lo, deftype_hi;
+
+static unsigned long set_mtrr_state(void)
 /*  [SUMMARY] Set the MTRR state for this CPU.
     <state> The MTRR state information to read.
     <ctxt> Some relevant CPU context.
@@ -217,14 +272,14 @@ static unsigned long set_mtrr_state(u32 deftype_lo, u32 deftype_hi)
                 if (set_mtrr_var_ranges(i, &mtrr_state.var_ranges[i]))
                         change_mask |= MTRR_CHANGE_MASK_VARIABLE;
 
-        if (set_fixed_ranges(mtrr_state.fixed_ranges))
+        if (mtrr_state.have_fixed && set_fixed_ranges(mtrr_state.fixed_ranges))
                 change_mask |= MTRR_CHANGE_MASK_FIXED;
 
         /*  Set_mtrr_restore restores the old value of MTRRdefType,
            so to set it we fiddle with the saved value  */
         if ((deftype_lo & 0xff) != mtrr_state.def_type
             || ((deftype_lo & 0xc00) >> 10) != mtrr_state.enabled) {
-                deftype_lo |= (mtrr_state.def_type | mtrr_state.enabled << 10);
+                deftype_lo = (deftype_lo & ~0xcff) | mtrr_state.def_type | (mtrr_state.enabled << 10);
                 change_mask |= MTRR_CHANGE_MASK_DEFTYPE;
         }
 
@@ -233,7 +288,6 @@ static unsigned long set_mtrr_state(u32 deftype_lo, u32 deftype_hi)
 
 
 static unsigned long cr4 = 0;
-static u32 deftype_lo, deftype_hi;
 static DEFINE_SPINLOCK(set_atomicity_lock);
 
 /*
@@ -271,7 +325,7 @@ static void prepare_set(void) __acquires(set_atomicity_lock)
         rdmsr(MTRRdefType_MSR, deftype_lo, deftype_hi);
 
         /*  Disable MTRRs, and set the default type to uncached  */
-        mtrr_wrmsr(MTRRdefType_MSR, deftype_lo & 0xf300UL, deftype_hi);
+        mtrr_wrmsr(MTRRdefType_MSR, deftype_lo & ~0xcff, deftype_hi);
 }
 
 static void post_set(void) __releases(set_atomicity_lock)
@@ -300,7 +354,7 @@ static void generic_set_all(void)
         prepare_set();
 
         /* Actually set the state */
-        mask = set_mtrr_state(deftype_lo,deftype_hi);
+        mask = set_mtrr_state();
 
         post_set();
         local_irq_restore(flags);
@@ -374,7 +428,7 @@ int generic_validate_add_page(unsigned long base, unsigned long size, unsigned i
                 }
         }
 
-        if (base < 0x100) {
+        if (base + size < 0x100) {
                 printk(KERN_WARNING "mtrr: cannot set region below 1 MiB (0x%lx000,0x%lx000)\n",
                        base, size);
                 return -EINVAL;
diff --git a/arch/i386/kernel/cpu/mtrr/if.c b/arch/i386/kernel/cpu/mtrr/if.c
index 5ac051bb9d55..9753bc6a1f3f 100644
--- a/arch/i386/kernel/cpu/mtrr/if.c
+++ b/arch/i386/kernel/cpu/mtrr/if.c
@@ -17,7 +17,7 @@ extern unsigned int *usage_table;
 
 #define FILE_FCOUNT(f) (((struct seq_file *)((f)->private_data))->private)
 
-static char *mtrr_strings[MTRR_NUM_TYPES] =
+static const char *const mtrr_strings[MTRR_NUM_TYPES] =
 {
     "uncachable",               /* 0 */
     "write-combining",          /* 1 */
@@ -28,7 +28,7 @@ static char *mtrr_strings[MTRR_NUM_TYPES] =
     "write-back",               /* 6 */
 };
 
-char *mtrr_attrib_to_str(int x)
+const char *mtrr_attrib_to_str(int x)
 {
         return (x <= 6) ? mtrr_strings[x] : "?";
 }
@@ -155,6 +155,7 @@ mtrr_ioctl(struct file *file, unsigned int cmd, unsigned long __arg)
 {
         int err = 0;
         mtrr_type type;
+        unsigned long size;
         struct mtrr_sentry sentry;
         struct mtrr_gentry gentry;
         void __user *arg = (void __user *) __arg;
@@ -235,15 +236,15 @@ mtrr_ioctl(struct file *file, unsigned int cmd, unsigned long __arg)
         case MTRRIOC_GET_ENTRY:
                 if (gentry.regnum >= num_var_ranges)
                         return -EINVAL;
-                mtrr_if->get(gentry.regnum, &gentry.base, &gentry.size, &type);
+                mtrr_if->get(gentry.regnum, &gentry.base, &size, &type);
 
                 /* Hide entries that go above 4GB */
-                if (gentry.base + gentry.size > 0x100000
-                    || gentry.size == 0x100000)
+                if (gentry.base + size - 1 >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT))
+                    || size >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT)))
                         gentry.base = gentry.size = gentry.type = 0;
                 else {
                         gentry.base <<= PAGE_SHIFT;
-                        gentry.size <<= PAGE_SHIFT;
+                        gentry.size = size << PAGE_SHIFT;
                         gentry.type = type;
                 }
 
@@ -273,8 +274,14 @@ mtrr_ioctl(struct file *file, unsigned int cmd, unsigned long __arg)
         case MTRRIOC_GET_PAGE_ENTRY:
                 if (gentry.regnum >= num_var_ranges)
                         return -EINVAL;
-                mtrr_if->get(gentry.regnum, &gentry.base, &gentry.size, &type);
-                gentry.type = type;
+                mtrr_if->get(gentry.regnum, &gentry.base, &size, &type);
+                /* Hide entries that would overflow */
+                if (size != (__typeof__(gentry.size))size)
+                        gentry.base = gentry.size = gentry.type = 0;
+                else {
+                        gentry.size = size;
+                        gentry.type = type;
+                }
                 break;
         }
 
@@ -353,8 +360,7 @@ static int mtrr_seq_show(struct seq_file *seq, void *offset)
         char factor;
         int i, max, len;
         mtrr_type type;
-        unsigned long base;
-        unsigned int size;
+        unsigned long base, size;
 
         len = 0;
         max = num_var_ranges;
@@ -373,7 +379,7 @@ static int mtrr_seq_show(struct seq_file *seq, void *offset)
                         }
                         /* RED-PEN: base can be > 32bit */ 
                         len += seq_printf(seq, 
-                                   "reg%02i: base=0x%05lx000 (%4liMB), size=%4i%cB: %s, count=%d\n",
+                                   "reg%02i: base=0x%05lx000 (%4luMB), size=%4lu%cB: %s, count=%d\n",
                              i, base, base >> (20 - PAGE_SHIFT), size, factor,
                              mtrr_attrib_to_str(type), usage_table[i]);
                 }
diff --git a/arch/i386/kernel/cpu/mtrr/main.c b/arch/i386/kernel/cpu/mtrr/main.c
index a4de30b9d3d3..aeea23e8a050 100644
--- a/arch/i386/kernel/cpu/mtrr/main.c
+++ b/arch/i386/kernel/cpu/mtrr/main.c
@@ -172,6 +172,13 @@ static void ipi_handler(void *info)
 
 #endif
 
+static inline int types_compatible(mtrr_type type1, mtrr_type type2) {
+        return type1 == MTRR_TYPE_UNCACHABLE ||
+               type2 == MTRR_TYPE_UNCACHABLE ||
+               (type1 == MTRR_TYPE_WRTHROUGH && type2 == MTRR_TYPE_WRBACK) ||
+               (type1 == MTRR_TYPE_WRBACK && type2 == MTRR_TYPE_WRTHROUGH);
+}
+
 /**
  * set_mtrr - update mtrrs on all processors
  * @reg:        mtrr in question
@@ -304,11 +311,9 @@ static void set_mtrr(unsigned int reg, unsigned long base,
 int mtrr_add_page(unsigned long base, unsigned long size, 
                   unsigned int type, char increment)
 {
-        int i;
+        int i, replace, error;
         mtrr_type ltype;
-        unsigned long lbase;
-        unsigned int lsize;
-        int error;
+        unsigned long lbase, lsize;
 
         if (!mtrr_if)
                 return -ENXIO;
@@ -328,12 +333,18 @@ int mtrr_add_page(unsigned long base, unsigned long size,
                 return -ENOSYS;
         }
 
+        if (!size) {
+                printk(KERN_WARNING "mtrr: zero sized request\n");
+                return -EINVAL;
+        }
+
         if (base & size_or_mask || size & size_or_mask) {
                 printk(KERN_WARNING "mtrr: base or size exceeds the MTRR width\n");
                 return -EINVAL;
         }
 
         error = -EINVAL;
+        replace = -1;
 
         /* No CPU hotplug when we change MTRR entries */
         lock_cpu_hotplug();
@@ -341,21 +352,28 @@ int mtrr_add_page(unsigned long base, unsigned long size,
         mutex_lock(&mtrr_mutex);
         for (i = 0; i < num_var_ranges; ++i) {
                 mtrr_if->get(i, &lbase, &lsize, &ltype);
-                if (base >= lbase + lsize)
-                        continue;
-                if ((base < lbase) && (base + size <= lbase))
+                if (!lsize || base > lbase + lsize - 1 || base + size - 1 < lbase)
                         continue;
                 /*  At this point we know there is some kind of overlap/enclosure  */
-                if ((base < lbase) || (base + size > lbase + lsize)) {
+                if (base < lbase || base + size - 1 > lbase + lsize - 1) {
+                        if (base <= lbase && base + size - 1 >= lbase + lsize - 1) {
+                                /*  New region encloses an existing region  */
+                                if (type == ltype) {
+                                        replace = replace == -1 ? i : -2;
+                                        continue;
+                                }
+                                else if (types_compatible(type, ltype))
+                                        continue;
+                        }
                         printk(KERN_WARNING
                                "mtrr: 0x%lx000,0x%lx000 overlaps existing"
-                               " 0x%lx000,0x%x000\n", base, size, lbase,
+                               " 0x%lx000,0x%lx000\n", base, size, lbase,
                                lsize);
                         goto out;
                 }
                 /*  New region is enclosed by an existing region  */
                 if (ltype != type) {
-                        if (type == MTRR_TYPE_UNCACHABLE)
+                        if (types_compatible(type, ltype))
                                 continue;
                         printk (KERN_WARNING "mtrr: type mismatch for %lx000,%lx000 old: %s new: %s\n",
                              base, size, mtrr_attrib_to_str(ltype),
@@ -368,10 +386,18 @@ int mtrr_add_page(unsigned long base, unsigned long size,
                 goto out;
         }
         /*  Search for an empty MTRR  */
-        i = mtrr_if->get_free_region(base, size);
+        i = mtrr_if->get_free_region(base, size, replace);
         if (i >= 0) {
                 set_mtrr(i, base, size, type);
-                usage_table[i] = 1;
+                if (likely(replace < 0))
+                        usage_table[i] = 1;
+                else {
+                        usage_table[i] = usage_table[replace] + !!increment;
+                        if (unlikely(replace != i)) {
+                                set_mtrr(replace, 0, 0, 0);
+                                usage_table[replace] = 0;
+                        }
+                }
         } else
                 printk(KERN_INFO "mtrr: no more MTRRs available\n");
         error = i;
@@ -459,8 +485,7 @@ int mtrr_del_page(int reg, unsigned long base, unsigned long size)
 {
         int i, max;
         mtrr_type ltype;
-        unsigned long lbase;
-        unsigned int lsize;
+        unsigned long lbase, lsize;
         int error = -EINVAL;
 
         if (!mtrr_if)
@@ -561,7 +586,7 @@ static void __init init_ifs(void)
 struct mtrr_value {
         mtrr_type       ltype;
         unsigned long   lbase;
-        unsigned int    lsize;
+        unsigned long   lsize;
 };
 
 static struct mtrr_value * mtrr_state;
diff --git a/arch/i386/kernel/cpu/mtrr/mtrr.h b/arch/i386/kernel/cpu/mtrr/mtrr.h
index 99c9f2682041..d61ea9db6cfe 100644
--- a/arch/i386/kernel/cpu/mtrr/mtrr.h
+++ b/arch/i386/kernel/cpu/mtrr/mtrr.h
@@ -43,15 +43,16 @@ struct mtrr_ops {
         void    (*set_all)(void);
 
         void    (*get)(unsigned int reg, unsigned long *base,
-                       unsigned int *size, mtrr_type * type);
-        int     (*get_free_region) (unsigned long base, unsigned long size);
-
+                       unsigned long *size, mtrr_type * type);
+        int     (*get_free_region)(unsigned long base, unsigned long size,
+                                   int replace_reg);
         int     (*validate_add_page)(unsigned long base, unsigned long size,
                                      unsigned int type);
         int     (*have_wrcomb)(void);
 };
 
-extern int generic_get_free_region(unsigned long base, unsigned long size);
+extern int generic_get_free_region(unsigned long base, unsigned long size,
+                                   int replace_reg);
 extern int generic_validate_add_page(unsigned long base, unsigned long size,
                                      unsigned int type);
 
@@ -62,17 +63,17 @@ extern int positive_have_wrcomb(void);
 /* library functions for processor-specific routines */
 struct set_mtrr_context {
         unsigned long flags;
-        unsigned long deftype_lo;
-        unsigned long deftype_hi;
         unsigned long cr4val;
-        unsigned long ccr3;
+        u32 deftype_lo;
+        u32 deftype_hi;
+        u32 ccr3;
 };
 
 struct mtrr_var_range {
-        unsigned long base_lo;
-        unsigned long base_hi;
-        unsigned long mask_lo;
-        unsigned long mask_hi;
+        u32 base_lo;
+        u32 base_hi;
+        u32 mask_lo;
+        u32 mask_hi;
 };
 
 void set_mtrr_done(struct set_mtrr_context *ctxt);
@@ -92,6 +93,6 @@ extern struct mtrr_ops * mtrr_if;
 extern unsigned int num_var_ranges;
 
 void mtrr_state_warn(void);
-char *mtrr_attrib_to_str(int x);
+const char *mtrr_attrib_to_str(int x);
 void mtrr_wrmsr(unsigned, unsigned, unsigned);