Disintegrate asm/system.h for IA64
Disintegrate asm/system.h for IA64.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Tony Luck <tony.luck@intel.com>
cc: linux-ia64@vger.kernel.org
diff --git a/arch/ia64/include/asm/switch_to.h b/arch/ia64/include/asm/switch_to.h
new file mode 100644
index 0000000..cb2412f
--- /dev/null
+++ b/arch/ia64/include/asm/switch_to.h
@@ -0,0 +1,87 @@
+/*
+ * Low-level task switching. This is based on information published in
+ * the Processor Abstraction Layer and the System Abstraction Layer
+ * manual.
+ *
+ * Copyright (C) 1998-2003 Hewlett-Packard Co
+ * David Mosberger-Tang <davidm@hpl.hp.com>
+ * Copyright (C) 1999 Asit Mallick <asit.k.mallick@intel.com>
+ * Copyright (C) 1999 Don Dugger <don.dugger@intel.com>
+ */
+#ifndef _ASM_IA64_SWITCH_TO_H
+#define _ASM_IA64_SWITCH_TO_H
+
+#include <linux/percpu.h>
+
+struct task_struct;
+
+/*
+ * Context switch from one thread to another. If the two threads have
+ * different address spaces, schedule() has already taken care of
+ * switching to the new address space by calling switch_mm().
+ *
+ * Disabling access to the fph partition and the debug-register
+ * context switch MUST be done before calling ia64_switch_to() since a
+ * newly created thread returns directly to
+ * ia64_ret_from_syscall_clear_r8.
+ */
+extern struct task_struct *ia64_switch_to (void *next_task);
+
+extern void ia64_save_extra (struct task_struct *task);
+extern void ia64_load_extra (struct task_struct *task);
+
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+extern void ia64_account_on_switch (struct task_struct *prev, struct task_struct *next);
+# define IA64_ACCOUNT_ON_SWITCH(p,n) ia64_account_on_switch(p,n)
+#else
+# define IA64_ACCOUNT_ON_SWITCH(p,n)
+#endif
+
+#ifdef CONFIG_PERFMON
+ DECLARE_PER_CPU(unsigned long, pfm_syst_info);
+# define PERFMON_IS_SYSWIDE() (__get_cpu_var(pfm_syst_info) & 0x1)
+#else
+# define PERFMON_IS_SYSWIDE() (0)
+#endif
+
+#define IA64_HAS_EXTRA_STATE(t) \
+ ((t)->thread.flags & (IA64_THREAD_DBG_VALID|IA64_THREAD_PM_VALID) \
+ || PERFMON_IS_SYSWIDE())
+
+#define __switch_to(prev,next,last) do { \
+ IA64_ACCOUNT_ON_SWITCH(prev, next); \
+ if (IA64_HAS_EXTRA_STATE(prev)) \
+ ia64_save_extra(prev); \
+ if (IA64_HAS_EXTRA_STATE(next)) \
+ ia64_load_extra(next); \
+ ia64_psr(task_pt_regs(next))->dfh = !ia64_is_local_fpu_owner(next); \
+ (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 other words: eager save, lazy restore.
+ */
+# define switch_to(prev,next,last) do { \
+ if (ia64_psr(task_pt_regs(prev))->mfh && ia64_is_local_fpu_owner(prev)) { \
+ ia64_psr(task_pt_regs(prev))->mfh = 0; \
+ (prev)->thread.flags |= IA64_THREAD_FPH_VALID; \
+ __ia64_save_fpu((prev)->thread.fph); \
+ } \
+ __switch_to(prev, next, last); \
+ /* "next" in old context is "current" in new context */ \
+ if (unlikely((current->thread.flags & IA64_THREAD_MIGRATION) && \
+ (task_cpu(current) != \
+ task_thread_info(current)->last_cpu))) { \
+ platform_migrate(current); \
+ task_thread_info(current)->last_cpu = task_cpu(current); \
+ } \
+} while (0)
+#else
+# define switch_to(prev,next,last) __switch_to(prev, next, last)
+#endif
+
+#endif /* _ASM_IA64_SWITCH_TO_H */