[ARM] add machine-specific hook to machine_kexec

Provide the option to call a machine-specific function
before kexec'ing a new kernel.
Signed-off-by: Eric Cooper <ecc@cmu.edu>
Signed-off-by: Nicolas Pitre <nico@fluxnic.net>

arch/arm/include/asm/kexec.h

@@ -50,6 +50,9 @@ static inline void crash_setup_regs(struct pt_regs *newregs,
 	}
 }
 
+/* Function pointer to optional machine-specific reinitialization */
+extern void (*kexec_reinit)(void);
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* CONFIG_KEXEC */

arch/arm/kernel/machine_kexec.c

@@ -75,6 +75,11 @@ void machine_crash_shutdown(struct pt_regs *regs)
 	printk(KERN_INFO "Loading crashdump kernel...\n");
 }
 
+/*
+ * Function pointer to optional machine-specific reinitialization
+ */
+void (*kexec_reinit)(void);
+
 void machine_kexec(struct kimage *image)
 {
 	unsigned long page_list;
@@ -104,6 +109,8 @@ void machine_kexec(struct kimage *image)
 			   (unsigned long) reboot_code_buffer + KEXEC_CONTROL_PAGE_SIZE);
 	printk(KERN_INFO "Bye!\n");
 
+	if (kexec_reinit)
+		kexec_reinit();
 	local_irq_disable();
 	local_fiq_disable();
 	setup_mm_for_reboot(0); /* mode is not used, so just pass 0*/