x86, acpi, idle: Restructure the mwait idle routines

[platform/adaptation/renesas_rcar/renesas_kernel.git] / arch / x86 / include / asm / mwait.h

diff --git a/arch/x86/include/asm/mwait.h b/arch/x86/include/asm/mwait.h
index 2f366d0..361b02e 100644 (file)
--- a/arch/x86/include/asm/mwait.h
+++ b/arch/x86/include/asm/mwait.h
@@ -1,6 +1,8 @@
 #ifndef _ASM_X86_MWAIT_H
 #define _ASM_X86_MWAIT_H
 
+#include <linux/sched.h>
+
 #define MWAIT_SUBSTATE_MASK            0xf
 #define MWAIT_CSTATE_MASK              0xf
 #define MWAIT_SUBSTATE_SIZE            4
@@ -13,4 +15,42 @@
 
 #define MWAIT_ECX_INTERRUPT_BREAK      0x1
 
+static inline void __monitor(const void *eax, unsigned long ecx,
+                            unsigned long edx)
+{
+       /* "monitor %eax, %ecx, %edx;" */
+       asm volatile(".byte 0x0f, 0x01, 0xc8;"
+                    :: "a" (eax), "c" (ecx), "d"(edx));
+}
+
+static inline void __mwait(unsigned long eax, unsigned long ecx)
+{
+       /* "mwait %eax, %ecx;" */
+       asm volatile(".byte 0x0f, 0x01, 0xc9;"
+                    :: "a" (eax), "c" (ecx));
+}
+
+/*
+ * This uses new MONITOR/MWAIT instructions on P4 processors with PNI,
+ * which can obviate IPI to trigger checking of need_resched.
+ * We execute MONITOR against need_resched and enter optimized wait state
+ * through MWAIT. Whenever someone changes need_resched, we would be woken
+ * up from MWAIT (without an IPI).
+ *
+ * New with Core Duo processors, MWAIT can take some hints based on CPU
+ * capability.
+ */
+static inline void mwait_idle_with_hints(unsigned long eax, unsigned long ecx)
+{
+       if (!current_set_polling_and_test()) {
+               if (this_cpu_has(X86_FEATURE_CLFLUSH_MONITOR))
+                       clflush((void *)&current_thread_info()->flags);
+
+               __monitor((void *)&current_thread_info()->flags, 0, 0);
+               if (!need_resched())
+                       __mwait(eax, ecx);
+       }
+       __current_clr_polling();
+}
+
 #endif /* _ASM_X86_MWAIT_H */