2 files changed, 65 insertions, 25 deletions

diff --git a/arch/i386/kernel/cpu/mtrr/generic.c b/arch/i386/kernel/cpu/mtrr/generic.c
index 150cf5055a3c..000c07e86433 100644
--- a/arch/i386/kernel/cpu/mtrr/generic.c
+++ b/arch/i386/kernel/cpu/mtrr/generic.c
@@ -20,6 +20,18 @@ struct mtrr_state {
         mtrr_type def_type;
 };
 
+struct fixed_range_block {
+        int base_msr; /* start address of an MTRR block */
+        int ranges;   /* number of MTRRs in this block  */
+};
+
+static struct fixed_range_block fixed_range_blocks[] = {
+        { MTRRfix64K_00000_MSR, 1 }, /* one  64k MTRR  */
+        { MTRRfix16K_80000_MSR, 2 }, /* two  16k MTRRs */
+        { MTRRfix4K_C0000_MSR,  8 }, /* eight 4k MTRRs */
+        {}
+};
+
 static unsigned long smp_changes_mask;
 static struct mtrr_state mtrr_state = {};
 
@@ -152,6 +164,44 @@ void mtrr_wrmsr(unsigned msr, unsigned a, unsigned b)
                         smp_processor_id(), msr, a, b);
 }
 
+/**
+ * Enable and allow read/write of extended fixed-range MTRR bits on K8 CPUs
+ * see AMD publication no. 24593, chapter 3.2.1 for more information
+ */
+static inline void k8_enable_fixed_iorrs(void)
+{
+        unsigned lo, hi;
+
+        rdmsr(MSR_K8_SYSCFG, lo, hi);
+        mtrr_wrmsr(MSR_K8_SYSCFG, lo
+                                | K8_MTRRFIXRANGE_DRAM_ENABLE
+                                | K8_MTRRFIXRANGE_DRAM_MODIFY, hi);
+}
+
+/**
+ * Checks and updates an fixed-range MTRR if it differs from the value it
+ * should have. If K8 extenstions are wanted, update the K8 SYSCFG MSR also.
+ * see AMD publication no. 24593, chapter 7.8.1, page 233 for more information
+ * \param msr MSR address of the MTTR which should be checked and updated
+ * \param changed pointer which indicates whether the MTRR needed to be changed
+ * \param msrwords pointer to the MSR values which the MSR should have
+ */
+static void set_fixed_range(int msr, int * changed, unsigned int * msrwords)
+{
+        unsigned lo, hi;
+
+        rdmsr(msr, lo, hi);
+
+        if (lo != msrwords[0] || hi != msrwords[1]) {
+                if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD &&
+                    boot_cpu_data.x86 == 15 &&
+                    ((msrwords[0] | msrwords[1]) & K8_MTRR_RDMEM_WRMEM_MASK))
+                        k8_enable_fixed_iorrs();
+                mtrr_wrmsr(msr, msrwords[0], msrwords[1]);
+                *changed = TRUE;
+        }
+}
+
 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.
@@ -201,36 +251,21 @@ static void generic_get_mtrr(unsigned int reg, unsigned long *base,
         *type = base_lo & 0xff;
 }
 
+/**
+ * Checks and updates the fixed-range MTRRs if they differ from the saved set
+ * \param frs pointer to fixed-range MTRR values, saved by get_fixed_ranges()
+ */
 static int set_fixed_ranges(mtrr_type * frs)
 {
-        unsigned int *p = (unsigned int *) frs;
+        unsigned long long *saved = (unsigned long long *) frs;
         int changed = FALSE;
-        int i;
-        unsigned int lo, hi;
+        int block=-1, range;
 
-        rdmsr(MTRRfix64K_00000_MSR, lo, hi);
-        if (p[0] != lo || p[1] != hi) {
-                mtrr_wrmsr(MTRRfix64K_00000_MSR, p[0], p[1]);
-                changed = TRUE;
-        }
-
-        for (i = 0; i < 2; i++) {
-                rdmsr(MTRRfix16K_80000_MSR + i, lo, hi);
-                if (p[2 + i * 2] != lo || p[3 + i * 2] != hi) {
-                        mtrr_wrmsr(MTRRfix16K_80000_MSR + i, p[2 + i * 2],
-                              p[3 + i * 2]);
-                        changed = TRUE;
-                }
-        }
+        while (fixed_range_blocks[++block].ranges)
+            for (range=0; range < fixed_range_blocks[block].ranges; range++)
+                set_fixed_range(fixed_range_blocks[block].base_msr + range,
+                    &changed, (unsigned int *) saved++);
 
-        for (i = 0; i < 8; i++) {
-                rdmsr(MTRRfix4K_C0000_MSR + i, lo, hi);
-                if (p[6 + i * 2] != lo || p[7 + i * 2] != hi) {
-                        mtrr_wrmsr(MTRRfix4K_C0000_MSR + i, p[6 + i * 2],
-                              p[7 + i * 2]);
-                        changed = TRUE;
-                }
-        }
         return changed;
 }
 
diff --git a/include/asm-i386/msr-index.h b/include/asm-i386/msr-index.h
index f1190802283d..a02eb2991349 100644
--- a/include/asm-i386/msr-index.h
+++ b/include/asm-i386/msr-index.h
@@ -87,6 +87,11 @@
 #define MSR_K7_CLK_CTL                  0xc001001b
 #define MSR_K8_TOP_MEM2                 0xc001001d
 #define MSR_K8_SYSCFG                   0xc0010010
+
+#define K8_MTRRFIXRANGE_DRAM_ENABLE     0x00040000 /* MtrrFixDramEn bit    */
+#define K8_MTRRFIXRANGE_DRAM_MODIFY     0x00080000 /* MtrrFixDramModEn bit */
+#define K8_MTRR_RDMEM_WRMEM_MASK        0x18181818 /* Mask: RdMem|WrMem    */
+
 #define MSR_K7_HWCR                     0xc0010015
 #define MSR_K8_HWCR                     0xc0010015
 #define MSR_K7_FID_VID_CTL              0xc0010041