7 files changed, 24 insertions, 32 deletions

diff --git a/arch/x86/include/asm/pat.h b/arch/x86/include/asm/pat.h
index 91bc4ba95f91..cdcff7f7f694 100644
--- a/arch/x86/include/asm/pat.h
+++ b/arch/x86/include/asm/pat.h
@@ -4,12 +4,7 @@
 #include <linux/types.h>
 #include <asm/pgtable_types.h>
 
-#ifdef CONFIG_X86_PAT
-extern int pat_enabled;
-#else
-static const int pat_enabled;
-#endif
-
+bool pat_enabled(void);
 extern void pat_init(void);
 void pat_init_cache_modes(void);
 
diff --git a/arch/x86/kernel/cpu/mtrr/main.c b/arch/x86/kernel/cpu/mtrr/main.c
index 383efb26e516..e7ed0d8ebacb 100644
--- a/arch/x86/kernel/cpu/mtrr/main.c
+++ b/arch/x86/kernel/cpu/mtrr/main.c
@@ -558,7 +558,7 @@ int arch_phys_wc_add(unsigned long base, unsigned long size)
 {
         int ret;
 
-        if (pat_enabled || !mtrr_enabled())
+        if (pat_enabled() || !mtrr_enabled())
                 return 0;  /* Success!  (We don't need to do anything.) */
 
         ret = mtrr_add(base, size, MTRR_TYPE_WRCOMB, true);
diff --git a/arch/x86/mm/iomap_32.c b/arch/x86/mm/iomap_32.c
index 9ca35fc60cfe..3a2ec8790ca7 100644
--- a/arch/x86/mm/iomap_32.c
+++ b/arch/x86/mm/iomap_32.c
@@ -82,7 +82,7 @@ iomap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot)
          * MTRR is UC or WC.  UC_MINUS gets the real intention, of the
          * user, which is "WC if the MTRR is WC, UC if you can't do that."
          */
-        if (!pat_enabled && pgprot_val(prot) ==
+        if (!pat_enabled() && pgprot_val(prot) ==
             (__PAGE_KERNEL | cachemode2protval(_PAGE_CACHE_MODE_WC)))
                 prot = __pgprot(__PAGE_KERNEL |
                                 cachemode2protval(_PAGE_CACHE_MODE_UC_MINUS));
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index a493bb83aa89..82d63ed70045 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -234,7 +234,7 @@ void __iomem *ioremap_nocache(resource_size_t phys_addr, unsigned long size)
 {
         /*
          * Ideally, this should be:
-         *      pat_enabled ? _PAGE_CACHE_MODE_UC : _PAGE_CACHE_MODE_UC_MINUS;
+         *      pat_enabled() ? _PAGE_CACHE_MODE_UC : _PAGE_CACHE_MODE_UC_MINUS;
          *
          * Till we fix all X drivers to use ioremap_wc(), we will use
          * UC MINUS. Drivers that are certain they need or can already
@@ -292,7 +292,7 @@ EXPORT_SYMBOL_GPL(ioremap_uc);
  */
 void __iomem *ioremap_wc(resource_size_t phys_addr, unsigned long size)
 {
-        if (pat_enabled)
+        if (pat_enabled())
                 return __ioremap_caller(phys_addr, size, _PAGE_CACHE_MODE_WC,
                                         __builtin_return_address(0));
         else
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 397838eb292b..70d221fe2eb4 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -1571,7 +1571,7 @@ int set_memory_wc(unsigned long addr, int numpages)
 {
         int ret;
 
-        if (!pat_enabled)
+        if (!pat_enabled())
                 return set_memory_uc(addr, numpages);
 
         ret = reserve_memtype(__pa(addr), __pa(addr) + numpages * PAGE_SIZE,
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 8c50b9bfa996..484dce7f759b 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -36,12 +36,11 @@
 #undef pr_fmt
 #define pr_fmt(fmt) "" fmt
 
-#ifdef CONFIG_X86_PAT
-int __read_mostly pat_enabled = 1;
+static int __read_mostly __pat_enabled = IS_ENABLED(CONFIG_X86_PAT);
 
 static inline void pat_disable(const char *reason)
 {
-        pat_enabled = 0;
+        __pat_enabled = 0;
         pr_info("x86/PAT: %s\n", reason);
 }
 
@@ -51,13 +50,11 @@ static int __init nopat(char *str)
         return 0;
 }
 early_param("nopat", nopat);
-#else
-static inline void pat_disable(const char *reason)
+
+bool pat_enabled(void)
 {
-        (void)reason;
+        return !!__pat_enabled;
 }
-#endif
-
 
 int pat_debug_enable;
 
@@ -201,7 +198,7 @@ void pat_init(void)
         u64 pat;
         bool boot_cpu = !boot_pat_state;
 
-        if (!pat_enabled)
+        if (!pat_enabled())
                 return;
 
         if (!cpu_has_pat) {
@@ -402,7 +399,7 @@ int reserve_memtype(u64 start, u64 end, enum page_cache_mode req_type,
 
         BUG_ON(start >= end); /* end is exclusive */
 
-        if (!pat_enabled) {
+        if (!pat_enabled()) {
                 /* This is identical to page table setting without PAT */
                 if (new_type) {
                         if (req_type == _PAGE_CACHE_MODE_WC)
@@ -477,7 +474,7 @@ int free_memtype(u64 start, u64 end)
         int is_range_ram;
         struct memtype *entry;
 
-        if (!pat_enabled)
+        if (!pat_enabled())
                 return 0;
 
         /* Low ISA region is always mapped WB. No need to track */
@@ -625,7 +622,7 @@ static inline int range_is_allowed(unsigned long pfn, unsigned long size)
         u64 to = from + size;
         u64 cursor = from;
 
-        if (!pat_enabled)
+        if (!pat_enabled())
                 return 1;
 
         while (cursor < to) {
@@ -661,7 +658,7 @@ int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
          * caching for the high addresses through the KEN pin, but
          * we maintain the tradition of paranoia in this code.
          */
-        if (!pat_enabled &&
+        if (!pat_enabled() &&
             !(boot_cpu_has(X86_FEATURE_MTRR) ||
               boot_cpu_has(X86_FEATURE_K6_MTRR) ||
               boot_cpu_has(X86_FEATURE_CYRIX_ARR) ||
@@ -730,7 +727,7 @@ static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t *vma_prot,
          * the type requested matches the type of first page in the range.
          */
         if (is_ram) {
-                if (!pat_enabled)
+                if (!pat_enabled())
                         return 0;
 
                 pcm = lookup_memtype(paddr);
@@ -844,7 +841,7 @@ int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
                 return ret;
         }
 
-        if (!pat_enabled)
+        if (!pat_enabled())
                 return 0;
 
         /*
@@ -872,7 +869,7 @@ int track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
 {
         enum page_cache_mode pcm;
 
-        if (!pat_enabled)
+        if (!pat_enabled())
                 return 0;
 
         /* Set prot based on lookup */
@@ -913,7 +910,7 @@ void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn,
 
 pgprot_t pgprot_writecombine(pgprot_t prot)
 {
-        if (pat_enabled)
+        if (pat_enabled())
                 return __pgprot(pgprot_val(prot) |
                                 cachemode2protval(_PAGE_CACHE_MODE_WC));
         else
@@ -996,7 +993,7 @@ static const struct file_operations memtype_fops = {
 
 static int __init pat_memtype_list_init(void)
 {
-        if (pat_enabled) {
+        if (pat_enabled()) {
                 debugfs_create_file("pat_memtype_list", S_IRUSR,
                                     arch_debugfs_dir, NULL, &memtype_fops);
         }
diff --git a/arch/x86/pci/i386.c b/arch/x86/pci/i386.c
index 349c0d32cc0b..0a9f2caf358f 100644
--- a/arch/x86/pci/i386.c
+++ b/arch/x86/pci/i386.c
@@ -429,12 +429,12 @@ int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma,
          * Caller can followup with UC MINUS request and add a WC mtrr if there
          * is a free mtrr slot.
          */
-        if (!pat_enabled && write_combine)
+        if (!pat_enabled() && write_combine)
                 return -EINVAL;
 
-        if (pat_enabled && write_combine)
+        if (pat_enabled() && write_combine)
                 prot |= cachemode2protval(_PAGE_CACHE_MODE_WC);
-        else if (pat_enabled || boot_cpu_data.x86 > 3)
+        else if (pat_enabled() || boot_cpu_data.x86 > 3)
                 /*
                  * ioremap() and ioremap_nocache() defaults to UC MINUS for now.
                  * To avoid attribute conflicts, request UC MINUS here