15 files changed, 38 insertions, 47 deletions
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 1f2ccccaf009..4231034b8128 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -211,6 +211,13 @@ void __cpuinit __cpu_die(unsigned int cpu)
        }
        printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
+        /*
+         * platform_cpu_kill() is generally expected to do the powering off
+         * and/or cutting of clocks to the dying CPU.  Optionally, this may
+         * be done by the CPU which is dying in preference to supporting
+         * this call, but that means there is _no_ synchronisation between
+         * the requesting CPU and the dying CPU actually losing power.
+         */
        if (!platform_cpu_kill(cpu))
                printk("CPU%u: unable to kill\n", cpu);
 }
@@ -230,14 +237,41 @@ void __ref cpu_die(void)
        idle_task_exit();
        local_irq_disable();
-        mb();
-        /* Tell __cpu_die() that this CPU is now safe to dispose of */
+        /*
+         * Flush the data out of the L1 cache for this CPU.  This must be
+         * before the completion to ensure that data is safely written out
+         * before platform_cpu_kill() gets called - which may disable
+         * *this* CPU and power down its cache.
+         */
+        flush_cache_louis();
+        /*
+         * Tell __cpu_die() that this CPU is now safe to dispose of.  Once
+         * this returns, power and/or clocks can be removed at any point
+         * from this CPU and its cache by platform_cpu_kill().
+         */
        RCU_NONIDLE(complete(&cpu_died));
        /*
-         * actual CPU shutdown procedure is at least platform (if not
+         * Ensure that the cache lines associated with that completion are
-         * CPU) specific.
+         * written out.  This covers the case where _this_ CPU is doing the
+         * powering down, to ensure that the completion is visible to the
+         * CPU waiting for this one.
+         */
+        flush_cache_louis();
+        /*
+         * The actual CPU shutdown procedure is at least platform (if not
+         * CPU) specific.  This may remove power, or it may simply spin.
+         *
+         * Platforms are generally expected *NOT* to return from this call,
+         * although there are some which do because they have no way to
+         * power down the CPU.  These platforms are the _only_ reason we
+         * have a return path which uses the fragment of assembly below.
+         *
+         * The return path should not be used for platforms which can
+         * power off the CPU.
         */
        if (smp_ops.cpu_die)
                smp_ops.cpu_die(cpu);
diff --git a/arch/arm/mach-exynos/hotplug.c b/arch/arm/mach-exynos/hotplug.c
index c3f825b27947..af90cfa2f826 100644
--- a/arch/arm/mach-exynos/hotplug.c
+++ b/arch/arm/mach-exynos/hotplug.c
@@ -28,7 +28,6 @@ static inline void cpu_enter_lowpower_a9(void)
 {
        unsigned int v;
-        flush_cache_all();
        asm volatile(
        "       mcr     p15, 0, %1, c7, c5, 0\n"
        "       mcr     p15, 0, %1, c7, c10, 4\n"
diff --git a/arch/arm/mach-highbank/hotplug.c b/arch/arm/mach-highbank/hotplug.c
index 890cae23c12a..a019e4e86e51 100644
--- a/arch/arm/mach-highbank/hotplug.c
+++ b/arch/arm/mach-highbank/hotplug.c
@@ -14,7 +14,6 @@
 * this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 #include <linux/kernel.h>
 #include <asm/cacheflush.h>
 #include "core.h"
diff --git a/arch/arm/mach-imx/hotplug.c b/arch/arm/mach-imx/hotplug.c
index 361a253e2b63..5e91112dcbee 100644
--- a/arch/arm/mach-imx/hotplug.c
+++ b/arch/arm/mach-imx/hotplug.c
@@ -11,7 +11,6 @@
 */
 #include <linux/errno.h>
-#include <asm/cacheflush.h>
 #include <asm/cp15.h>
 #include "common.h"
@@ -20,7 +19,6 @@ static inline void cpu_enter_lowpower(void)
 {
        unsigned int v;
-        flush_cache_all();
        asm volatile(
                "mcr    p15, 0, %1, c7, c5, 0\n"
        "       mcr     p15, 0, %1, c7, c10, 4\n"
diff --git a/arch/arm/mach-msm/hotplug.c b/arch/arm/mach-msm/hotplug.c
index 750446feb444..326a87261f9a 100644
--- a/arch/arm/mach-msm/hotplug.c
+++ b/arch/arm/mach-msm/hotplug.c
@@ -10,16 +10,12 @@
 #include <linux/errno.h>
 #include <linux/smp.h>
-#include <asm/cacheflush.h>
 #include <asm/smp_plat.h>
 #include "common.h"
 static inline void cpu_enter_lowpower(void)
 {
-        /* Just flush the cache. Changing the coherency is not yet
-         * available on msm. */
-        flush_cache_all();
 }
 static inline void cpu_leave_lowpower(void)
diff --git a/arch/arm/mach-omap2/omap-hotplug.c b/arch/arm/mach-omap2/omap-hotplug.c
index e712d1725a8b..ceb30a59bf28 100644
--- a/arch/arm/mach-omap2/omap-hotplug.c
+++ b/arch/arm/mach-omap2/omap-hotplug.c
@@ -35,9 +35,6 @@ void __ref omap4_cpu_die(unsigned int cpu)
        unsigned int boot_cpu = 0;
        void __iomem *base = omap_get_wakeupgen_base();
-        flush_cache_all();
-        dsb();
        /*
         * we're ready for shutdown now, so do it
         */
diff --git a/arch/arm/mach-prima2/hotplug.c b/arch/arm/mach-prima2/hotplug.c
index f4b17cbababd..0ab2f8bae28e 100644
--- a/arch/arm/mach-prima2/hotplug.c
+++ b/arch/arm/mach-prima2/hotplug.c
@@ -10,13 +10,10 @@
 #include <linux/errno.h>
 #include <linux/smp.h>
-#include <asm/cacheflush.h>
 #include <asm/smp_plat.h>
 static inline void platform_do_lowpower(unsigned int cpu)
 {
-        flush_cache_all();
        /* we put the platform to just WFI */
        for (;;) {
                __asm__ __volatile__("dsb\n\t" "wfi\n\t"
diff --git a/arch/arm/mach-realview/hotplug.c b/arch/arm/mach-realview/hotplug.c
index 53818e5cd3ad..ac22dd41b135 100644
--- a/arch/arm/mach-realview/hotplug.c
+++ b/arch/arm/mach-realview/hotplug.c
@@ -12,7 +12,6 @@
 #include <linux/errno.h>
 #include <linux/smp.h>
-#include <asm/cacheflush.h>
 #include <asm/cp15.h>
 #include <asm/smp_plat.h>
@@ -20,7 +19,6 @@ static inline void cpu_enter_lowpower(void)
 {
        unsigned int v;
-        flush_cache_all();
        asm volatile(
        "       mcr     p15, 0, %1, c7, c5, 0\n"
        "       mcr     p15, 0, %1, c7, c10, 4\n"
diff --git a/arch/arm/mach-shmobile/smp-sh73a0.c b/arch/arm/mach-shmobile/smp-sh73a0.c
index acb46a94ccdf..2f1ef1bc805d 100644
--- a/arch/arm/mach-shmobile/smp-sh73a0.c
+++ b/arch/arm/mach-shmobile/smp-sh73a0.c
@@ -119,14 +119,6 @@ static int sh73a0_cpu_kill(unsigned int cpu)
 static void sh73a0_cpu_die(unsigned int cpu)
 {
-        /*
-         * The ARM MPcore does not issue a cache coherency request for the L1
-         * cache when powering off single CPUs. We must take care of this and
-         * further caches.
-         */
-        dsb();
-        flush_cache_all();
        /* Set power off mode. This takes the CPU out of the MP cluster */
        scu_power_mode(scu_base_addr(), SCU_PM_POWEROFF);
diff --git a/arch/arm/mach-spear13xx/hotplug.c b/arch/arm/mach-spear13xx/hotplug.c
index a7d2dd11a4f2..d97749c642ce 100644
--- a/arch/arm/mach-spear13xx/hotplug.c
+++ b/arch/arm/mach-spear13xx/hotplug.c
@@ -13,7 +13,6 @@
 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/smp.h>
-#include <asm/cacheflush.h>
 #include <asm/cp15.h>
 #include <asm/smp_plat.h>
@@ -21,7 +20,6 @@ static inline void cpu_enter_lowpower(void)
 {
        unsigned int v;
-        flush_cache_all();
        asm volatile(
        "       mcr     p15, 0, %1, c7, c5, 0\n"
        "       dsb\n"
diff --git a/arch/arm/mach-tegra/common.h b/arch/arm/mach-tegra/common.h
index 32f8eb3fe344..5900cc44f780 100644
--- a/arch/arm/mach-tegra/common.h
+++ b/arch/arm/mach-tegra/common.h
@@ -2,4 +2,3 @@ extern struct smp_operations tegra_smp_ops;
 extern int tegra_cpu_kill(unsigned int cpu);
 extern void tegra_cpu_die(unsigned int cpu);
-extern int tegra_cpu_disable(unsigned int cpu);
diff --git a/arch/arm/mach-tegra/hotplug.c b/arch/arm/mach-tegra/hotplug.c
index a599f6e36dea..e8323bc95770 100644
--- a/arch/arm/mach-tegra/hotplug.c
+++ b/arch/arm/mach-tegra/hotplug.c
@@ -12,7 +12,6 @@
 #include <linux/smp.h>
 #include <linux/clk/tegra.h>
-#include <asm/cacheflush.h>
 #include <asm/smp_plat.h>
 #include "sleep.h"
@@ -47,15 +46,6 @@ void __ref tegra_cpu_die(unsigned int cpu)
        BUG();
 }
-int tegra_cpu_disable(unsigned int cpu)
-{
-        /*
-         * we don't allow CPU 0 to be shutdown (it is still too special
-         * e.g. clock tick interrupts)
-         */
-        return cpu == 0 ? -EPERM : 0;
-}
 #ifdef CONFIG_ARCH_TEGRA_2x_SOC
 extern void tegra20_hotplug_shutdown(void);
 void __init tegra20_hotplug_init(void)
diff --git a/arch/arm/mach-tegra/platsmp.c b/arch/arm/mach-tegra/platsmp.c
index 2c6b3d55213b..ec33ec86aad9 100644
--- a/arch/arm/mach-tegra/platsmp.c
+++ b/arch/arm/mach-tegra/platsmp.c
@@ -192,6 +192,5 @@ struct smp_operations tegra_smp_ops __initdata = {
 #ifdef CONFIG_HOTPLUG_CPU
        .cpu_kill               = tegra_cpu_kill,
        .cpu_die                = tegra_cpu_die,
-        .cpu_disable            = tegra_cpu_disable,
 #endif
 };
diff --git a/arch/arm/mach-ux500/hotplug.c b/arch/arm/mach-ux500/hotplug.c
index 2f6af259015d..1c55a55dd89e 100644
--- a/arch/arm/mach-ux500/hotplug.c
+++ b/arch/arm/mach-ux500/hotplug.c
@@ -12,7 +12,6 @@
 #include <linux/errno.h>
 #include <linux/smp.h>
-#include <asm/cacheflush.h>
 #include <asm/smp_plat.h>
 #include <mach/setup.h>
@@ -24,8 +23,6 @@
 */
 void __ref ux500_cpu_die(unsigned int cpu)
 {
-        flush_cache_all();
        /* directly enter low power state, skipping secure registers */
        for (;;) {
                __asm__ __volatile__("dsb\n\t" "wfi\n\t"
diff --git a/arch/arm/mach-vexpress/hotplug.c b/arch/arm/mach-vexpress/hotplug.c
index a141b98d84fe..f0ce6b8f5e71 100644
--- a/arch/arm/mach-vexpress/hotplug.c
+++ b/arch/arm/mach-vexpress/hotplug.c
@@ -12,7 +12,6 @@
 #include <linux/errno.h>
 #include <linux/smp.h>
-#include <asm/cacheflush.h>
 #include <asm/smp_plat.h>
 #include <asm/cp15.h>
@@ -20,7 +19,6 @@ static inline void cpu_enter_lowpower(void)
 {
        unsigned int v;
-        flush_cache_all();
        asm volatile(
                "mcr    p15, 0, %1, c7, c5, 0\n"
        "       mcr     p15, 0, %1, c7, c10, 4\n"