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authorJens Axboe <axboe@kernel.dk>2013-07-02 08:31:48 +0200
committerJens Axboe <axboe@kernel.dk>2013-07-02 08:31:48 +0200
commit5f0e5afa0de4522abb3ea7d1369039b94e740ec5 (patch)
tree6a5be3db9ecfed8ef2150c6146f6d1e0d658ac8b /arch/arm/kernel/process.c
parentd752b2696072ed52fd5afab08b601e2220a3b87e (diff)
parent9e895ace5d82df8929b16f58e9f515f6d54ab82d (diff)
downloadop-kernel-dev-5f0e5afa0de4522abb3ea7d1369039b94e740ec5.zip
op-kernel-dev-5f0e5afa0de4522abb3ea7d1369039b94e740ec5.tar.gz
Merge tag 'v3.10-rc7' into for-3.11/drivers
Linux 3.10-rc7 Pull this in early to avoid doing it with the bcache merge, since there are a number of changes to bcache between my old base (3.10-rc1) and the new pull request.
Diffstat (limited to 'arch/arm/kernel/process.c')
-rw-r--r--arch/arm/kernel/process.c44
1 files changed, 37 insertions, 7 deletions
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index f219703..6e8931c 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -184,30 +184,61 @@ int __init reboot_setup(char *str)
__setup("reboot=", reboot_setup);
+/*
+ * Called by kexec, immediately prior to machine_kexec().
+ *
+ * This must completely disable all secondary CPUs; simply causing those CPUs
+ * to execute e.g. a RAM-based pin loop is not sufficient. This allows the
+ * kexec'd kernel to use any and all RAM as it sees fit, without having to
+ * avoid any code or data used by any SW CPU pin loop. The CPU hotplug
+ * functionality embodied in disable_nonboot_cpus() to achieve this.
+ */
void machine_shutdown(void)
{
-#ifdef CONFIG_SMP
- smp_send_stop();
-#endif
+ disable_nonboot_cpus();
}
+/*
+ * Halting simply requires that the secondary CPUs stop performing any
+ * activity (executing tasks, handling interrupts). smp_send_stop()
+ * achieves this.
+ */
void machine_halt(void)
{
- machine_shutdown();
+ smp_send_stop();
+
local_irq_disable();
while (1);
}
+/*
+ * Power-off simply requires that the secondary CPUs stop performing any
+ * activity (executing tasks, handling interrupts). smp_send_stop()
+ * achieves this. When the system power is turned off, it will take all CPUs
+ * with it.
+ */
void machine_power_off(void)
{
- machine_shutdown();
+ smp_send_stop();
+
if (pm_power_off)
pm_power_off();
}
+/*
+ * Restart requires that the secondary CPUs stop performing any activity
+ * while the primary CPU resets the system. Systems with a single CPU can
+ * use soft_restart() as their machine descriptor's .restart hook, since that
+ * will cause the only available CPU to reset. Systems with multiple CPUs must
+ * provide a HW restart implementation, to ensure that all CPUs reset at once.
+ * This is required so that any code running after reset on the primary CPU
+ * doesn't have to co-ordinate with other CPUs to ensure they aren't still
+ * executing pre-reset code, and using RAM that the primary CPU's code wishes
+ * to use. Implementing such co-ordination would be essentially impossible.
+ */
void machine_restart(char *cmd)
{
- machine_shutdown();
+ smp_send_stop();
arm_pm_restart(reboot_mode, cmd);
@@ -411,7 +442,6 @@ static struct vm_area_struct gate_vma = {
.vm_start = 0xffff0000,
.vm_end = 0xffff0000 + PAGE_SIZE,
.vm_flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC,
- .vm_mm = &init_mm,
};
static int __init gate_vma_init(void)
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