Module: xenomai-forge
Branch: next
Commit: 74a6da47cfc5d33aaf4c12576d6ed6f12b33957c
URL:    
http://git.xenomai.org/?p=xenomai-forge.git;a=commit;h=74a6da47cfc5d33aaf4c12576d6ed6f12b33957c

Author: Gilles Chanteperdrix <gilles.chanteperd...@xenomai.org>
Date:   Sat Jul  5 12:01:03 2014 +0200

arch/x86: implement C1E state workaround

---

 kernel/cobalt/arch/x86/Makefile                  |    2 +-
 kernel/cobalt/arch/x86/c1e.c                     |   72 ++++++++++++++++++++++
 kernel/cobalt/arch/x86/include/asm/xenomai/c1e.h |   23 +++++++
 kernel/cobalt/arch/x86/machine.c                 |    2 +
 4 files changed, 98 insertions(+), 1 deletion(-)

diff --git a/kernel/cobalt/arch/x86/Makefile b/kernel/cobalt/arch/x86/Makefile
index e6f5024..c70d0f3 100644
--- a/kernel/cobalt/arch/x86/Makefile
+++ b/kernel/cobalt/arch/x86/Makefile
@@ -1,5 +1,5 @@
 
 obj-$(CONFIG_XENOMAI) += xeno_machine.o
-xeno_machine-y := machine.o mayday.o thread.o smi.o
+xeno_machine-y := machine.o mayday.o thread.o smi.o c1e.o
 
 ccflags-y := -Iarch/x86/xenomai/include -Iinclude/xenomai
diff --git a/kernel/cobalt/arch/x86/c1e.c b/kernel/cobalt/arch/x86/c1e.c
new file mode 100644
index 0000000..9aa4c66
--- /dev/null
+++ b/kernel/cobalt/arch/x86/c1e.c
@@ -0,0 +1,72 @@
+/*
+ * Disable Intel automatic promotion to C1E mode.
+ * Lifted from drivers/idle/intel_idle.c
+ * Copyright (c) 2013, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+#include <linux/smp.h>
+#include <asm/processor.h>
+#include <asm/cpu_device_id.h>
+#include <asm/msr.h>
+
+#define ICPU(model) \
+       { X86_VENDOR_INTEL, 6, model, X86_FEATURE_MWAIT, 1UL }
+
+static const struct x86_cpu_id c1e_ids[] = {
+       ICPU(0x1a),
+       ICPU(0x1e),
+       ICPU(0x1f),
+       ICPU(0x25),
+       ICPU(0x2c),
+       ICPU(0x2e),
+       ICPU(0x2f),
+       ICPU(0x2a),
+       ICPU(0x2d),
+       ICPU(0x3a),
+       ICPU(0x3e),
+       ICPU(0x3c),
+       ICPU(0x3f),
+       ICPU(0x45),
+       ICPU(0x46),
+       ICPU(0x4D),
+       {}
+};
+
+#undef ICPU
+
+static void c1e_promotion_disable(void *dummy)
+{
+       unsigned long long msr_bits;
+
+       rdmsrl(MSR_IA32_POWER_CTL, msr_bits);
+       msr_bits &= ~0x2;
+       wrmsrl(MSR_IA32_POWER_CTL, msr_bits);
+}
+
+void __init mach_x86_c1e_disable(void)
+{
+       const struct x86_cpu_id *id;
+
+       id = x86_match_cpu(c1e_ids);
+       if (id) {
+               printk("[Xenomai] disabling automatic C1E state promotion on 
Intel processor\n");
+               /*
+                * cpu uses C1E, disable this feature (copied from
+                * intel_idle driver)
+                */
+               on_each_cpu(c1e_promotion_disable, NULL, 1);
+       }
+}
diff --git a/kernel/cobalt/arch/x86/include/asm/xenomai/c1e.h 
b/kernel/cobalt/arch/x86/include/asm/xenomai/c1e.h
new file mode 100644
index 0000000..7e06014
--- /dev/null
+++ b/kernel/cobalt/arch/x86/include/asm/xenomai/c1e.h
@@ -0,0 +1,23 @@
+/*
+ * Copyright (C) 2014 Gilles Chanteperdrix <gilles.chanteperd...@xenomai.org>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+#ifndef C1E_H
+#define C1E_H
+
+void mach_x86_c1e_disable(void);
+
+#endif /* C1E_H */
diff --git a/kernel/cobalt/arch/x86/machine.c b/kernel/cobalt/arch/x86/machine.c
index e669199..3ce34ae 100644
--- a/kernel/cobalt/arch/x86/machine.c
+++ b/kernel/cobalt/arch/x86/machine.c
@@ -22,6 +22,7 @@
 #include <cobalt/kernel/arith.h>
 #include <asm/xenomai/machine.h>
 #include <asm/xenomai/smi.h>
+#include <asm/xenomai/c1e.h>
 
 #ifdef __i386__
 
@@ -144,6 +145,7 @@ static unsigned long mach_x86_calibrate(void)
 
 static int mach_x86_init(void)
 {
+       mach_x86_c1e_disable();
        mach_x86_smi_init();
        mach_x86_smi_disable();
 


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