x86: introduce rdtsc_barrier()

[linux-2.6-omap-h63xx.git] / include / asm-x86 / system.h

diff --git a/include/asm-x86/system.h b/include/asm-x86/system.h
index ba3403f1d020ec9c92db925deb5a795e864713ff..39474f2957a3c872a4b49202bd42eee08fc94763 100644 (file)
--- a/include/asm-x86/system.h
+++ b/include/asm-x86/system.h
@@ -2,11 +2,22 @@
 #define _ASM_X86_SYSTEM_H_
 
 #include <asm/asm.h>
+#include <asm/segment.h>
+#include <asm/cpufeature.h>
+#include <asm/cmpxchg.h>
+#include <asm/nops.h>
 
 #include <linux/kernel.h>
+#include <linux/irqflags.h>
+
+/* entries in ARCH_DLINFO: */
+#ifdef CONFIG_IA32_EMULATION
+# define AT_VECTOR_SIZE_ARCH 2
+#else
+# define AT_VECTOR_SIZE_ARCH 1
+#endif
 
 #ifdef CONFIG_X86_32
-#define AT_VECTOR_SIZE_ARCH 2 /* entries in ARCH_DLINFO */
 
 struct task_struct; /* one of the stranger aspects of C forward declarations */
 extern struct task_struct *FASTCALL(__switch_to(struct task_struct *prev,
@@ -34,7 +45,10 @@ extern struct task_struct *FASTCALL(__switch_to(struct task_struct *prev,
                      "2" (prev), "d" (next));                          \
 } while (0)
 
-# include "system_32.h"
+/*
+ * disable hlt during certain critical i/o operations
+ */
+#define HAVE_DISABLE_HLT
 #else
 #define __SAVE(reg, offset) "movq %%" #reg ",(14-" #offset ")*8(%%rsp)\n\t"
 #define __RESTORE(reg, offset) "movq (14-" #offset ")*8(%%rsp),%%" #reg "\n\t"
@@ -49,7 +63,7 @@ extern struct task_struct *FASTCALL(__switch_to(struct task_struct *prev,
 
 /* Save restore flags to clear handle leaking NT */
 #define switch_to(prev, next, last) \
-       asm volatile(SAVE_CONTEXT                                         \
+       asm volatile(SAVE_CONTEXT                                                   \
             "movq %%rsp,%P[threadrsp](%[prev])\n\t" /* save RSP */       \
             "movq %P[threadrsp](%[next]),%%rsp\n\t" /* restore RSP */    \
             "call __switch_to\n\t"                                       \
@@ -69,7 +83,6 @@ extern struct task_struct *FASTCALL(__switch_to(struct task_struct *prev,
               [thread_info] "i" (offsetof(struct task_struct, stack)),   \
               [pda_pcurrent] "i" (offsetof(struct x8664_pda, pcurrent))  \
             : "memory", "cc" __EXTRA_CLOBBER)
-# include "system_64.h"
 #endif
 
 #ifdef __KERNEL__
@@ -236,6 +249,22 @@ static inline void native_wbinvd(void)
 #define write_cr4(x)   (native_write_cr4(x))
 #define wbinvd()       (native_wbinvd())
 
+#ifdef CONFIG_X86_64
+
+static inline unsigned long read_cr8(void)
+{
+       unsigned long cr8;
+       asm volatile("movq %%cr8,%0" : "=r" (cr8));
+       return cr8;
+}
+
+static inline void write_cr8(unsigned long val)
+{
+       asm volatile("movq %0,%%cr8" :: "r" (val) : "memory");
+}
+
+#endif
+
 /* Clear the 'TS' bit */
 #define clts()         (native_clts())
 
@@ -367,5 +396,17 @@ void default_idle(void);
 #define set_mb(var, value) do { var = value; barrier(); } while (0)
 #endif
 
+/*
+ * Stop RDTSC speculation. This is needed when you need to use RDTSC
+ * (or get_cycles or vread that possibly accesses the TSC) in a defined
+ * code region.
+ *
+ * (Could use an alternative three way for this if there was one.)
+ */
+static inline void rdtsc_barrier(void)
+{
+       alternative(ASM_NOP3, "mfence", X86_FEATURE_MFENCE_RDTSC);
+       alternative(ASM_NOP3, "lfence", X86_FEATURE_LFENCE_RDTSC);
+}
 
 #endif