2 files changed, 14 insertions, 0 deletions

diff --git a/arch/x86/kernel/setup_64.c b/arch/x86/kernel/setup_64.c
index 3d76dbd9f2c0..b5425979501c 100644
--- a/arch/x86/kernel/setup_64.c
+++ b/arch/x86/kernel/setup_64.c
@@ -729,6 +729,19 @@ static void __cpuinit init_amd(struct cpuinfo_x86 *c)
 
         if (amd_apic_timer_broken())
                 disable_apic_timer = 1;
+
+        if (c == &boot_cpu_data && c->x86 >= 0xf && c->x86 <= 0x11) {
+                unsigned long long tseg;
+
+                /*
+                 * Split up direct mapping around the TSEG SMM area.
+                 * Don't do it for gbpages because there seems very little
+                 * benefit in doing so.
+                 */
+                if (!rdmsrl_safe(MSR_K8_TSEG_ADDR, &tseg) &&
+                (tseg >> PMD_SHIFT) < (max_pfn_mapped >> (PMD_SHIFT-PAGE_SHIFT)))
+                        set_memory_4k((unsigned long)__va(tseg), 1);
+        }
 }
 
 void __cpuinit detect_ht(struct cpuinfo_x86 *c)
diff --git a/include/asm-x86/msr-index.h b/include/asm-x86/msr-index.h
index af4e07f661b8..09413ad39d3c 100644
--- a/include/asm-x86/msr-index.h
+++ b/include/asm-x86/msr-index.h
@@ -112,6 +112,7 @@
 #define MSR_K8_SYSCFG                   0xc0010010
 #define MSR_K8_HWCR                     0xc0010015
 #define MSR_K8_ENABLE_C1E               0xc0010055
+#define MSR_K8_TSEG_ADDR                0xc0010112
 #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    */