[PATCH 4/6] ARM: reset: add reset functionality for jumping to a physical address

On Mon, 6 Jun 2011, Will Deacon wrote:

Tools such as kexec and CPU hotplug require a way to reset the processor
and branch to some code in physical space. This requires various bits of
jiggery pokery with the caches and MMU which, when it goes wrong, tends
to lock up the system.

This patch implements a new function, arm_machine_reset, for
consolidating this code in one place where it can be used by multiple
subsystems.

[ ... ]

+void arm_machine_reset(unsigned long reset_code_phys)
+{
+	unsigned long cpu_reset_end = PAGE_ALIGN((unsigned long)cpu_reset);
+	/* This is stricter than necessary but better to be safe than sorry. */
+	BUG_ON(virt_to_phys((void *)cpu_reset_end) >= TASK_SIZE);
+
+	/* Disable interrupts first */
+	local_irq_disable();
+	local_fiq_disable();
+
+	/*
+	 * Clean and invalidate L2.
+	 * This is racy, so we must be the last guy left.
+	 */
+	WARN_ON(num_online_cpus() > 1);
+	/* Flush while we still have locking available to us. */
+	outer_flush_all();
+	outer_disable();
+	/* Data destroyed here will only be speculative. */
+	outer_inv_all();
+
+	prepare_for_reboot(0);
+
+	/* Switch to the identity mapping. */
+	((typeof(cpu_reset) *)virt_to_phys((void *)cpu_reset))(reset_code_phys);

void (*reset_func)(unsigned long) = virt_to_phys(cpu_reset)

+}
+
/*
 * Function pointers to optional machine specific functions
 */
-- 
1.7.0.4