10 files changed, 40 insertions, 4 deletions

diff --git a/src/cpu/amd/agesa/Kconfig b/src/cpu/amd/agesa/Kconfig
index 5ec5ce8b1d..b7e69e015a 100644
--- a/src/cpu/amd/agesa/Kconfig
+++ b/src/cpu/amd/agesa/Kconfig
@@ -25,6 +25,7 @@ config CPU_AMD_AGESA
         default y if CPU_AMD_AGESA_FAMILY15
         default y if CPU_AMD_AGESA_FAMILY15_TN
         default n
+	select TSC_SYNC_LFENCE
 
 if CPU_AMD_AGESA
 
diff --git a/src/cpu/amd/model_10xxx/Kconfig b/src/cpu/amd/model_10xxx/Kconfig
index 221d0449ac..0890771e34 100644
--- a/src/cpu/amd/model_10xxx/Kconfig
+++ b/src/cpu/amd/model_10xxx/Kconfig
@@ -3,6 +3,7 @@ config CPU_AMD_MODEL_10XXX
 	select SSE
 	select SSE2
 	select MMCONF_SUPPORT_DEFAULT
+	select TSC_SYNC_LFENCE
 
 if CPU_AMD_MODEL_10XXX
 config CPU_ADDR_BITS
diff --git a/src/cpu/amd/model_fxx/Kconfig b/src/cpu/amd/model_fxx/Kconfig
index e04605bfbe..0afc4b0f4c 100644
--- a/src/cpu/amd/model_fxx/Kconfig
+++ b/src/cpu/amd/model_fxx/Kconfig
@@ -3,6 +3,7 @@ config CPU_AMD_MODEL_FXX
 	select MMX
 	select SSE
 	select SSE2
+	select TSC_SYNC_LFENCE
 
 if CPU_AMD_MODEL_FXX
 config UDELAY_IO
diff --git a/src/cpu/intel/model_1067x/Kconfig b/src/cpu/intel/model_1067x/Kconfig
index b079922275..852c9cdf0c 100644
--- a/src/cpu/intel/model_1067x/Kconfig
+++ b/src/cpu/intel/model_1067x/Kconfig
@@ -2,3 +2,4 @@ config CPU_INTEL_MODEL_1067X
 	bool
 	select SMP
 	select SSE2
+	select TSC_SYNC_MFENCE
diff --git a/src/cpu/intel/model_106cx/Kconfig b/src/cpu/intel/model_106cx/Kconfig
index 103ed50d3e..7a75ec1ba3 100644
--- a/src/cpu/intel/model_106cx/Kconfig
+++ b/src/cpu/intel/model_106cx/Kconfig
@@ -4,9 +4,9 @@ config CPU_INTEL_MODEL_106CX
 	select SSE2
 	select UDELAY_LAPIC
 	select AP_IN_SIPI_WAIT
+	select TSC_SYNC_MFENCE
 
 config CPU_ADDR_BITS
 	int
 	default 32
 
-
diff --git a/src/cpu/intel/model_206ax/Kconfig b/src/cpu/intel/model_206ax/Kconfig
index 9cc6edd94e..6635868453 100644
--- a/src/cpu/intel/model_206ax/Kconfig
+++ b/src/cpu/intel/model_206ax/Kconfig
@@ -14,6 +14,7 @@ config CPU_SPECIFIC_OPTIONS
 	select SMM_TSEG
 	select MICROCODE_IN_CBFS
 	#select AP_IN_SIPI_WAIT
+	select TSC_SYNC_MFENCE
 
 config BOOTBLOCK_CPU_INIT
 	string
diff --git a/src/cpu/intel/model_6ex/Kconfig b/src/cpu/intel/model_6ex/Kconfig
index 31d24bd68f..e2b1986132 100644
--- a/src/cpu/intel/model_6ex/Kconfig
+++ b/src/cpu/intel/model_6ex/Kconfig
@@ -4,3 +4,4 @@ config CPU_INTEL_MODEL_6EX
 	select SSE2
 	select UDELAY_LAPIC
 	select AP_IN_SIPI_WAIT
+	select TSC_SYNC_MFENCE
diff --git a/src/cpu/intel/model_6fx/Kconfig b/src/cpu/intel/model_6fx/Kconfig
index 851685cb06..4517f17fa6 100644
--- a/src/cpu/intel/model_6fx/Kconfig
+++ b/src/cpu/intel/model_6fx/Kconfig
@@ -4,3 +4,4 @@ config CPU_INTEL_MODEL_6FX
 	select SSE2
 	select UDELAY_LAPIC
 	select AP_IN_SIPI_WAIT
+	select TSC_SYNC_MFENCE
diff --git a/src/cpu/x86/Kconfig b/src/cpu/x86/Kconfig
index 07e9d9ecbf..9a96aeadd8 100644
--- a/src/cpu/x86/Kconfig
+++ b/src/cpu/x86/Kconfig
@@ -23,6 +23,22 @@ config TSC_CALIBRATE_WITH_IO
 	bool
 	default n
 
+config TSC_SYNC_LFENCE
+	bool
+	default n
+	help
+	  The CPU driver should select this if the CPU needs
+	  to execute an lfence instruction in order to synchronize
+	  rdtsc. This is true for all modern AMD CPUs.
+
+config TSC_SYNC_MFENCE
+	bool
+	default n
+	help
+	  The CPU driver should select this if the CPU needs
+	  to execute an mfence instruction in order to synchronize
+	  rdtsc. This is true for all modern Intel CPUs.
+
 config XIP_ROM_SIZE
 	hex
 	default ROM_SIZE if ROMCC
diff --git a/src/include/cpu/x86/tsc.h b/src/include/cpu/x86/tsc.h
index c57362755a..6ce7f5fc7d 100644
--- a/src/include/cpu/x86/tsc.h
+++ b/src/include/cpu/x86/tsc.h
@@ -1,6 +1,14 @@
 #ifndef CPU_X86_TSC_H
 #define CPU_X86_TSC_H
 
+#if CONFIG_TSC_SYNC_MFENCE
+#define TSC_SYNC "mfence\n"
+#elif CONFIG_TSC_SYNC_LFENCE
+#define TSC_SYNC "lfence\n"
+#else
+#define TSC_SYNC
+#endif
+
 struct tsc_struct {
 	unsigned lo;
 	unsigned hi;
@@ -10,10 +18,11 @@ typedef struct tsc_struct tsc_t;
 static inline tsc_t rdtsc(void)
 {
 	tsc_t res;
-	__asm__ __volatile__ (
+	asm volatile (
+		TSC_SYNC
 		"rdtsc"
 		: "=a" (res.lo), "=d"(res.hi) /* outputs */
-		);
+	);
 	return res;
 }
 
@@ -22,7 +31,11 @@ static inline tsc_t rdtsc(void)
 static inline unsigned long long rdtscll(void)
 {
 	unsigned long long val;
-	asm volatile ("rdtsc" : "=A" (val));
+	asm volatile (
+		TSC_SYNC
+		"rdtsc"
+		: "=A" (val)
+	);
 	return val;
 }
 #endif