Fix arch headers.

[linux-flexiantxendom0-3.2.10.git] / include / asm-ia64 / system.h

diff --git a/include/asm-ia64/system.h b/include/asm-ia64/system.h
index 1486785..250c0fa 100644 (file)
--- a/include/asm-ia64/system.h
+++ b/include/asm-ia64/system.h
@@ -212,48 +212,39 @@ extern void ia64_load_extra (struct task_struct *task);
 # define PERFMON_IS_SYSWIDE() (0)
 #endif
 
-#define __switch_to(prev,next,last) do {                                               \
-       if (((prev)->thread.flags & (IA64_THREAD_DBG_VALID|IA64_THREAD_PM_VALID))       \
-           || IS_IA32_PROCESS(ia64_task_regs(prev)) || PERFMON_IS_SYSWIDE())           \
-               ia64_save_extra(prev);                                                  \
-       if (((next)->thread.flags & (IA64_THREAD_DBG_VALID|IA64_THREAD_PM_VALID))       \
-           || IS_IA32_PROCESS(ia64_task_regs(next)) || PERFMON_IS_SYSWIDE())           \
-               ia64_load_extra(next);                                                  \
-       (last) = ia64_switch_to((next));                                                \
+#define IA64_HAS_EXTRA_STATE(t)                                                        \
+       ((t)->thread.flags & (IA64_THREAD_DBG_VALID|IA64_THREAD_PM_VALID)       \
+        || IS_IA32_PROCESS(ia64_task_regs(t)) || PERFMON_IS_SYSWIDE())
+
+#define __switch_to(prev,next,last) do {                                                        \
+       struct task_struct *__fpu_owner = ia64_get_fpu_owner();                                  \
+       if (IA64_HAS_EXTRA_STATE(prev))                                                          \
+               ia64_save_extra(prev);                                                           \
+       if (IA64_HAS_EXTRA_STATE(next))                                                          \
+               ia64_load_extra(next);                                                           \
+       ia64_psr(ia64_task_regs(next))->dfh =                                                    \
+               !(__fpu_owner == (next) && ((next)->thread.last_fph_cpu == smp_processor_id())); \
+       (last) = ia64_switch_to((next));                                                         \
 } while (0)
 
 #ifdef CONFIG_SMP
-
 /*
- * In the SMP case, we save the fph state when context-switching
- * away from a thread that modified fph.  This way, when the thread
- * gets scheduled on another CPU, the CPU can pick up the state from
- * task->thread.fph, avoiding the complication of having to fetch
- * the latest fph state from another CPU.
+ * In the SMP case, we save the fph state when context-switching away from a thread that
+ * modified fph.  This way, when the thread gets scheduled on another CPU, the CPU can
+ * pick up the state from task->thread.fph, avoiding the complication of having to fetch
+ * the latest fph state from another CPU.  In other words: eager save, lazy restore.
  */
-# define switch_to(prev,next,last) do {                                        \
-       if (ia64_psr(ia64_task_regs(prev))->mfh) {                      \
-               ia64_psr(ia64_task_regs(prev))->mfh = 0;                \
-               (prev)->thread.flags |= IA64_THREAD_FPH_VALID;          \
-               __ia64_save_fpu((prev)->thread.fph);                    \
-               (prev)->thread.last_fph_cpu = smp_processor_id();       \
-       }                                                               \
-       if ((next)->thread.flags & IA64_THREAD_FPH_VALID) {             \
-               if (((next)->thread.last_fph_cpu == smp_processor_id()) \
-                   && (ia64_get_fpu_owner() == next))                  \
-               {                                                       \
-                       ia64_psr(ia64_task_regs(next))->dfh = 0;        \
-                       ia64_psr(ia64_task_regs(next))->mfh = 0;        \
-               } else                                                  \
-                       ia64_psr(ia64_task_regs(next))->dfh = 1;        \
-       }                                                               \
-       __switch_to(prev,next,last);                                    \
-  } while (0)
-#else
 # define switch_to(prev,next,last) do {                                                \
-       ia64_psr(ia64_task_regs(next))->dfh = (ia64_get_fpu_owner() != (next)); \
-       __switch_to(prev,next,last);                                            \
+       if (ia64_psr(ia64_task_regs(prev))->mfh) {                              \
+               ia64_psr(ia64_task_regs(prev))->mfh = 0;                        \
+               (prev)->thread.flags |= IA64_THREAD_FPH_VALID;                  \
+               __ia64_save_fpu((prev)->thread.fph);                            \
+               (prev)->thread.last_fph_cpu = smp_processor_id();               \
+       }                                                                       \
+       __switch_to(prev, next, last);                                          \
 } while (0)
+#else
+# define switch_to(prev,next,last)     __switch_to(prev, next, last)
 #endif
 
 /*