5 files changed, 63 insertions, 2 deletions

diff --git a/arch/x86/include/asm/pat.h b/arch/x86/include/asm/pat.h
index 150407a7234d..91bc4ba95f91 100644
--- a/arch/x86/include/asm/pat.h
+++ b/arch/x86/include/asm/pat.h
@@ -11,6 +11,7 @@ static const int pat_enabled;
 #endif
 
 extern void pat_init(void);
+void pat_init_cache_modes(void);
 
 extern int reserve_memtype(u64 start, u64 end,
                 enum page_cache_mode req_pcm, enum page_cache_mode *ret_pcm);
diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index 6d5f6d154215..af447f95e3be 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -351,6 +351,10 @@ extern uint8_t __pte2cachemode_tbl[8];
         ((((cb) >> (_PAGE_BIT_PAT - 2)) & 4) |          \
          (((cb) >> (_PAGE_BIT_PCD - 1)) & 2) |          \
          (((cb) >> _PAGE_BIT_PWT) & 1))
+#define __cm_idx2pte(i)                                 \
+        ((((i) & 4) << (_PAGE_BIT_PAT - 2)) |           \
+         (((i) & 2) << (_PAGE_BIT_PCD - 1)) |           \
+         (((i) & 1) << _PAGE_BIT_PWT))
 
 static inline unsigned long cachemode2protval(enum page_cache_mode pcm)
 {
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index a9776ba475d4..82b41d56bb98 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -716,3 +716,11 @@ void __init zone_sizes_init(void)
         free_area_init_nodes(max_zone_pfns);
 }
 
+void update_cache_mode_entry(unsigned entry, enum page_cache_mode cache)
+{
+        /* entry 0 MUST be WB (hardwired to speed up translations) */
+        BUG_ON(!entry && cache != _PAGE_CACHE_MODE_WB);
+
+        __cachemode2pte_tbl[cache] = __cm_idx2pte(entry);
+        __pte2cachemode_tbl[entry] = cache;
+}
diff --git a/arch/x86/mm/mm_internal.h b/arch/x86/mm/mm_internal.h
index 6b563a118891..62474ba66c8e 100644
--- a/arch/x86/mm/mm_internal.h
+++ b/arch/x86/mm/mm_internal.h
@@ -16,4 +16,6 @@ void zone_sizes_init(void);
 
 extern int after_bootmem;
 
+void update_cache_mode_entry(unsigned entry, enum page_cache_mode cache);
+
 #endif  /* __X86_MM_INTERNAL_H */
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index ef75f3f89810..4c601276a556 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -31,6 +31,7 @@
 #include <asm/io.h>
 
 #include "pat_internal.h"
+#include "mm_internal.h"
 
 #ifdef CONFIG_X86_PAT
 int __read_mostly pat_enabled = 1;
@@ -75,6 +76,52 @@ enum {
         PAT_UC_MINUS = 7,       /* UC, but can be overriden by MTRR */
 };
 
+#define CM(c) (_PAGE_CACHE_MODE_ ## c)
+
+static enum page_cache_mode pat_get_cache_mode(unsigned pat_val, char *msg)
+{
+        enum page_cache_mode cache;
+        char *cache_mode;
+
+        switch (pat_val) {
+        case PAT_UC:       cache = CM(UC);       cache_mode = "UC  "; break;
+        case PAT_WC:       cache = CM(WC);       cache_mode = "WC  "; break;
+        case PAT_WT:       cache = CM(WT);       cache_mode = "WT  "; break;
+        case PAT_WP:       cache = CM(WP);       cache_mode = "WP  "; break;
+        case PAT_WB:       cache = CM(WB);       cache_mode = "WB  "; break;
+        case PAT_UC_MINUS: cache = CM(UC_MINUS); cache_mode = "UC- "; break;
+        default:           cache = CM(WB);       cache_mode = "WB  "; break;
+        }
+
+        memcpy(msg, cache_mode, 4);
+
+        return cache;
+}
+
+#undef CM
+
+/*
+ * Update the cache mode to pgprot translation tables according to PAT
+ * configuration.
+ * Using lower indices is preferred, so we start with highest index.
+ */
+void pat_init_cache_modes(void)
+{
+        int i;
+        enum page_cache_mode cache;
+        char pat_msg[33];
+        u64 pat;
+
+        rdmsrl(MSR_IA32_CR_PAT, pat);
+        pat_msg[32] = 0;
+        for (i = 7; i >= 0; i--) {
+                cache = pat_get_cache_mode((pat >> (i * 8)) & 7,
+                                           pat_msg + 4 * i);
+                update_cache_mode_entry(i, cache);
+        }
+        pr_info("PAT configuration [0-7]: %s\n", pat_msg);
+}
+
 #define PAT(x, y)       ((u64)PAT_ ## y << ((x)*8))
 
 void pat_init(void)
@@ -124,8 +171,7 @@ void pat_init(void)
         wrmsrl(MSR_IA32_CR_PAT, pat);
 
         if (boot_cpu)
-                printk(KERN_INFO "x86 PAT enabled: cpu %d, old 0x%Lx, new 0x%Lx\n",
-                       smp_processor_id(), boot_pat_state, pat);
+                pat_init_cache_modes();
 }
 
 #undef PAT