ARM: deprecate support for old way to pass kernel parameters

This was deprecated in 2001 and announced to live on for 5 years.

For now provide a kernel parameter for those who still need it.
Acked-by: Eric Miao <eric.miao@canonical.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

arch/arm/Kconfig

@@ -1374,6 +1374,12 @@ config UACCESS_WITH_MEMCPY
 	  However, if the CPU data cache is using a write-allocate mode,
 	  this option is unlikely to provide any performance gain.
 
+config DEPRECATED_PARAM_STRUCT
+	bool "Provide old way to pass kernel parameters"
+	help
+	  This was deprecated in 2001 and announced to live on for 5 years.
+	  Some old boot loaders still use this way.
+
 endmenu
 
 menu "Boot options"

arch/arm/kernel/Makefile

@@ -13,10 +13,12 @@ CFLAGS_REMOVE_return_address.o = -pg
 
 # Object file lists.
 
-obj-y		:= compat.o elf.o entry-armv.o entry-common.o irq.o \
+obj-y		:= elf.o entry-armv.o entry-common.o irq.o \
 		   process.o ptrace.o return_address.o setup.o signal.o \
 		   sys_arm.o stacktrace.o time.o traps.o
 
+obj-$(CONFIG_DEPRECATED_PARAM_STRUCT) += compat.o
+
 obj-$(CONFIG_LEDS)		+= leds.o
 obj-$(CONFIG_OC_ETM)		+= etm.o
 

arch/arm/kernel/compat.c

@@ -217,10 +217,3 @@ void __init convert_to_tag_list(struct tag *tags)
 	struct param_struct *params = (struct param_struct *)tags;
 	build_tag_list(params, &params->u2);
 }
-
-void __init squash_mem_tags(struct tag *tag)
-{
-	for (; tag->hdr.size; tag = tag_next(tag))
-		if (tag->hdr.tag == ATAG_MEM)
-			tag->hdr.tag = ATAG_NONE;
-}

arch/arm/kernel/compat.h

@@ -9,5 +9,3 @@
 */
 
 extern void convert_to_tag_list(struct tag *tags);
-
-extern void squash_mem_tags(struct tag *tag);

arch/arm/kernel/setup.c

@@ -44,7 +44,9 @@
 #include <asm/traps.h>
 #include <asm/unwind.h>
 
+#if defined(CONFIG_DEPRECATED_PARAM_STRUCT)
 #include "compat.h"
+#endif
 #include "atags.h"
 #include "tcm.h"
 
@@ -663,6 +665,13 @@ static int __init customize_machine(void)
 }
 arch_initcall(customize_machine);
 
+static void __init squash_mem_tags(struct tag *tag)
+{
+	for (; tag->hdr.size; tag = tag_next(tag))
+		if (tag->hdr.tag == ATAG_MEM)
+			tag->hdr.tag = ATAG_NONE;
+}
+
 void __init setup_arch(char **cmdline_p)
 {
 	struct tag *tags = (struct tag *)&init_tags;
@@ -683,12 +692,14 @@ void __init setup_arch(char **cmdline_p)
 	else if (mdesc->boot_params)
 		tags = phys_to_virt(mdesc->boot_params);
 
+#if defined(CONFIG_DEPRECATED_PARAM_STRUCT)
 	/*
 	 * If we have the old style parameters, convert them to
 	 * a tag list.
 	 */
 	if (tags->hdr.tag != ATAG_CORE)
 		convert_to_tag_list(tags);
+#endif
 	if (tags->hdr.tag != ATAG_CORE)
 		tags = (struct tag *)&init_tags;