x86: enable PAT for amd k8 and fam10h

make known_pat_cpu to think amd k8 and fam10h is ok too.

also make tom2 below to be WRBACK

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

3 files changed, 24 insertions, 1 deletions

diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c
index 011e07e99cd1..74ec2ea4ed3e 100644
--- a/arch/x86/kernel/cpu/mtrr/generic.c
+++ b/arch/x86/kernel/cpu/mtrr/generic.c
@@ -37,6 +37,7 @@ static struct fixed_range_block fixed_range_blocks[] = {
 static unsigned long smp_changes_mask;
 static struct mtrr_state mtrr_state = {};
 static int mtrr_state_set;
+static u64 tom2;
 
 #undef MODULE_PARAM_PREFIX
 #define MODULE_PARAM_PREFIX "mtrr."
@@ -138,6 +139,11 @@ u8 mtrr_type_lookup(u64 start, u64 end)
                 }
         }
 
+        if (tom2) {
+                if (start >= (1ULL<<32) && (end < tom2))
+                        return MTRR_TYPE_WRBACK;
+        }
+
         if (prev_match != 0xFF)
                 return prev_match;
 
@@ -206,6 +212,15 @@ void __init get_mtrr_state(void)
         mtrr_state.def_type = (lo & 0xff);
         mtrr_state.enabled = (lo & 0xc00) >> 10;
 
+        if (amd_special_default_mtrr()) {
+                unsigned lo, hi;
+                /* TOP_MEM2 */
+                rdmsr(MSR_K8_TOP_MEM2, lo, hi);
+                tom2 = hi;
+                tom2 <<= 32;
+                tom2 |= lo;
+                tom2 &= 0xffffff8000000ULL;
+        }
         if (mtrr_show) {
                 int high_width;
 
@@ -236,6 +251,8 @@ void __init get_mtrr_state(void)
                         else
                                 printk(KERN_INFO "MTRR %u disabled\n", i);
                 }
+                if (tom2)
+                        printk(KERN_INFO "TOM2: %016lx aka %ldM\n", tom2, tom2>>20);
         }
         mtrr_state_set = 1;
 
diff --git a/arch/x86/kernel/cpu/mtrr/main.c b/arch/x86/kernel/cpu/mtrr/main.c
index a6450b3ae759..6a1e278d9323 100644
--- a/arch/x86/kernel/cpu/mtrr/main.c
+++ b/arch/x86/kernel/cpu/mtrr/main.c
@@ -627,7 +627,7 @@ early_param("disable_mtrr_trim", disable_mtrr_trim_setup);
 #define Tom2Enabled (1U << 21)
 #define Tom2ForceMemTypeWB (1U << 22)
 
-static __init int amd_special_default_mtrr(void)
+int __init amd_special_default_mtrr(void)
 {
         u32 l, h;
 
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 57a2af36d6ee..0648a2225b09 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -47,6 +47,12 @@ static int pat_known_cpu(void)
                         return 1;
                 }
         }
+        if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD &&
+             boot_cpu_data.x86 >= 0xf && boot_cpu_data.x86 <= 0x11) {
+                if (cpu_has_pat) {
+                        return 1;
+                }
+        }
 
         pat_wc_enabled = 0;
         printk(KERN_INFO "CPU and/or kernel does not support PAT.\n");