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authorYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 12:17:53 -0700
committerYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 15:44:42 -0700
commit9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch)
tree1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/arch/ia64/include/asm/switch_to.h
parent98260f3884f4a202f9ca5eabed40b1354c489b29 (diff)
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/arch/ia64/include/asm/switch_to.h')
-rw-r--r--kernel/arch/ia64/include/asm/switch_to.h79
1 files changed, 79 insertions, 0 deletions
diff --git a/kernel/arch/ia64/include/asm/switch_to.h b/kernel/arch/ia64/include/asm/switch_to.h
new file mode 100644
index 000000000..e8f3585e7
--- /dev/null
+++ b/kernel/arch/ia64/include/asm/switch_to.h
@@ -0,0 +1,79 @@
+/*
+ * 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_PERFMON
+ DECLARE_PER_CPU(unsigned long, pfm_syst_info);
+# define PERFMON_IS_SYSWIDE() (__this_cpu_read(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 { \
+ 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 */