[Xen-devel] [PATCH 3/5] cpuidle: replace xen access to x86 pm_idle and default_idle

[Len Brown <lenb@xxxxxxxxxx>]

From: Len Brown <len.brown@xxxxxxxxx>

When a Xen Dom0 kernel boots on a hypervisor, it gets access
to the raw-hardware ACPI tables.  While it parses the idle tables
for the hypervisor's beneift, it uses HLT for its own idle.

Rather than have xen scribble on pm_idle and access default_idle,
have it simply disable_cpuidle() so acpi_idle will not load and
architecture default HLT will be used.

cc: xen-devel@xxxxxxxxxxxxxxxxxxx
Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Signed-off-by: Len Brown <len.brown@xxxxxxxxx>
---
 arch/x86/xen/setup.c      |    3 ++-
 drivers/cpuidle/cpuidle.c |    4 ++++
 include/linux/cpuidle.h   |    2 ++
 3 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 60aeeb5..a9627e2 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -9,6 +9,7 @@
 #include <linux/mm.h>
 #include <linux/pm.h>
 #include <linux/memblock.h>
+#include <linux/cpuidle.h>
 
 #include <asm/elf.h>
 #include <asm/vdso.h>
@@ -426,7 +427,7 @@ void __init xen_arch_setup(void)
 #ifdef CONFIG_X86_32
        boot_cpu_data.hlt_works_ok = 1;
 #endif
-       pm_idle = default_idle;
+       disable_cpuidle();
        boot_option_idle_override = IDLE_HALT;
 
        fiddle_vdso();
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index faae2c3..041df0b 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -34,6 +34,10 @@ int cpuidle_disabled(void)
 {
        return off;
 }
+void disable_cpuidle(void)
+{
+       off = 1;
+}
 
 #if defined(CONFIG_ARCH_HAS_CPU_IDLE_WAIT)
 static void cpuidle_kick_cpus(void)
diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index 36719ea..b89f67d 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -122,6 +122,7 @@ struct cpuidle_driver {
 };
 
 #ifdef CONFIG_CPU_IDLE
+extern void disable_cpuidle(void);
 
 extern int cpuidle_register_driver(struct cpuidle_driver *drv);
 struct cpuidle_driver *cpuidle_get_driver(void);
@@ -135,6 +136,7 @@ extern int cpuidle_enable_device(struct cpuidle_device 
*dev);
 extern void cpuidle_disable_device(struct cpuidle_device *dev);
 
 #else
+static inline void disable_cpuidle(void) { }
 
 static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
 {return -ENODEV; }
-- 
1.7.6.396.ge0613


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