[PATCH 1/2] ARM: split out ATAGS parsing

[PATCH 1/2] ARM: split out ATAGS parsing

[Nicolas Pitre]

Make ATAGS parsing into a source file of its own, namely atags_parse.c.
Also rename compat.c to atags_compat.c to make it clearer what it is
about.  Same for atags.c which is now atags_proc.c. Gather all the atags
function declarations into a common atags.h.

Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
---
 arch/arm/kernel/Makefile                     |   6 +-
 arch/arm/kernel/atags.h                      |   3 +
 arch/arm/kernel/{compat.c => atags_compat.c} |   4 +-
 arch/arm/kernel/atags_parse.c                | 238 +++++++++++++++++++++++++++
 arch/arm/kernel/{atags.c => atags_proc.c}    |   0
 arch/arm/kernel/compat.h                     |  11 --
 arch/arm/kernel/setup.c                      | 236 +-------------------------
 7 files changed, 247 insertions(+), 251 deletions(-)
 rename arch/arm/kernel/{compat.c => atags_compat.c} (99%)
 create mode 100644 arch/arm/kernel/atags_parse.c
 rename arch/arm/kernel/{atags.c => atags_proc.c} (100%)
 delete mode 100644 arch/arm/kernel/compat.h

diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index 7ad2d5cf70..086c9d3bc3 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -15,11 +15,11 @@ CFLAGS_REMOVE_return_address.o = -pg
 
 # Object file lists.
 
-obj-y		:= elf.o entry-armv.o entry-common.o irq.o opcodes.o \
+obj-y		:= atags_parse.o elf.o entry-armv.o entry-common.o irq.o opcodes.o \
 		   process.o ptrace.o return_address.o sched_clock.o \
 		   setup.o signal.o stacktrace.o sys_arm.o time.o traps.o
 
-obj-$(CONFIG_DEPRECATED_PARAM_STRUCT) += compat.o
+obj-$(CONFIG_DEPRECATED_PARAM_STRUCT) += atags_compat.o
 
 obj-$(CONFIG_LEDS)		+= leds.o
 obj-$(CONFIG_OC_ETM)		+= etm.o
@@ -52,7 +52,7 @@ test-kprobes-objs		+= kprobes-test-thumb.o
 else
 test-kprobes-objs		+= kprobes-test-arm.o
 endif
-obj-$(CONFIG_ATAGS_PROC)	+= atags.o
+obj-$(CONFIG_ATAGS_PROC)	+= atags_proc.o
 obj-$(CONFIG_OABI_COMPAT)	+= sys_oabi-compat.o
 obj-$(CONFIG_ARM_THUMBEE)	+= thumbee.o
 obj-$(CONFIG_KGDB)		+= kgdb.o
diff --git a/arch/arm/kernel/atags.h b/arch/arm/kernel/atags.h
index e5f028d214..a888fdd381 100644
--- a/arch/arm/kernel/atags.h
+++ b/arch/arm/kernel/atags.h
@@ -3,3 +3,6 @@ extern void save_atags(struct tag *tags);
 #else
 static inline void save_atags(struct tag *tags) { }
 #endif
+
+void convert_to_tag_list(struct tag *tags);
+struct machine_desc *setup_machine_tags(phys_addr_t __atags_pointer, unsigned int machine_nr);
diff --git a/arch/arm/kernel/compat.c b/arch/arm/kernel/atags_compat.c
similarity index 99%
rename from arch/arm/kernel/compat.c
rename to arch/arm/kernel/atags_compat.c
index 925652318b..5236ad38f4 100644
--- a/arch/arm/kernel/compat.c
+++ b/arch/arm/kernel/atags_compat.c
@@ -1,5 +1,5 @@
 /*
- *  linux/arch/arm/kernel/compat.c
+ *  linux/arch/arm/kernel/atags_compat.c
  *
  *  Copyright (C) 2001 Russell King
  *
@@ -26,7 +26,7 @@
 
 #include <asm/mach/arch.h>
 
-#include "compat.h"
+#include "atags.h"
 
 /*
  * Usage:
diff --git a/arch/arm/kernel/atags_parse.c b/arch/arm/kernel/atags_parse.c
new file mode 100644
index 0000000000..18f13be99e
--- /dev/null
+++ b/arch/arm/kernel/atags_parse.c
@@ -0,0 +1,238 @@
+/*
+ * Tag parsing.
+ *
+ * Copyright (C) 1995-2001 Russell King
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+/*
+ * This is the traditional way of passing data to the kernel at boot time.  Rather
+ * than passing a fixed inflexible structure to the kernel, we pass a list
+ * of variable-sized tags to the kernel.  The first tag must be a ATAG_CORE
+ * tag for the list to be recognised (to distinguish the tagged list from
+ * a param_struct).  The list is terminated with a zero-length tag (this tag
+ * is not parsed in any way).
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/root_dev.h>
+#include <linux/screen_info.h>
+
+#include <asm/setup.h>
+#include <asm/system_info.h>
+#include <asm/page.h>
+#include <asm/mach/arch.h>
+
+#include "atags.h"
+
+static char default_command_line[COMMAND_LINE_SIZE] __initdata = CONFIG_CMDLINE;
+
+#ifndef MEM_SIZE
+#define MEM_SIZE	(16*1024*1024)
+#endif
+
+static struct {
+	struct tag_header hdr1;
+	struct tag_core   core;
+	struct tag_header hdr2;
+	struct tag_mem32  mem;
+	struct tag_header hdr3;
+} default_tags __initdata = {
+	{ tag_size(tag_core), ATAG_CORE },
+	{ 1, PAGE_SIZE, 0xff },
+	{ tag_size(tag_mem32), ATAG_MEM },
+	{ MEM_SIZE },
+	{ 0, ATAG_NONE }
+};
+
+static int __init parse_tag_core(const struct tag *tag)
+{
+	if (tag->hdr.size > 2) {
+		if ((tag->u.core.flags & 1) == 0)
+			root_mountflags &= ~MS_RDONLY;
+		ROOT_DEV = old_decode_dev(tag->u.core.rootdev);
+	}
+	return 0;
+}
+
+__tagtable(ATAG_CORE, parse_tag_core);
+
+static int __init parse_tag_mem32(const struct tag *tag)
+{
+	return arm_add_memory(tag->u.mem.start, tag->u.mem.size);
+}
+
+__tagtable(ATAG_MEM, parse_tag_mem32);
+
+#if defined(CONFIG_VGA_CONSOLE) || defined(CONFIG_DUMMY_CONSOLE)
+static int __init parse_tag_videotext(const struct tag *tag)
+{
+	screen_info.orig_x            = tag->u.videotext.x;
+	screen_info.orig_y            = tag->u.videotext.y;
+	screen_info.orig_video_page   = tag->u.videotext.video_page;
+	screen_info.orig_video_mode   = tag->u.videotext.video_mode;
+	screen_info.orig_video_cols   = tag->u.videotext.video_cols;
+	screen_info.orig_video_ega_bx = tag->u.videotext.video_ega_bx;
+	screen_info.orig_video_lines  = tag->u.videotext.video_lines;
+	screen_info.orig_video_isVGA  = tag->u.videotext.video_isvga;
+	screen_info.orig_video_points = tag->u.videotext.video_points;
+	return 0;
+}
+
+__tagtable(ATAG_VIDEOTEXT, parse_tag_videotext);
+#endif
+
+#ifdef CONFIG_BLK_DEV_RAM
+static int __init parse_tag_ramdisk(const struct tag *tag)
+{
+	extern int rd_size, rd_image_start, rd_prompt, rd_doload;
+
+	rd_image_start = tag->u.ramdisk.start;
+	rd_doload = (tag->u.ramdisk.flags & 1) == 0;
+	rd_prompt = (tag->u.ramdisk.flags & 2) == 0;
+
+	if (tag->u.ramdisk.size)
+		rd_size = tag->u.ramdisk.size;
+
+	return 0;
+}
+
+__tagtable(ATAG_RAMDISK, parse_tag_ramdisk);
+#endif
+
+static int __init parse_tag_serialnr(const struct tag *tag)
+{
+	system_serial_low = tag->u.serialnr.low;
+	system_serial_high = tag->u.serialnr.high;
+	return 0;
+}
+
+__tagtable(ATAG_SERIAL, parse_tag_serialnr);
+
+static int __init parse_tag_revision(const struct tag *tag)
+{
+	system_rev = tag->u.revision.rev;
+	return 0;
+}
+
+__tagtable(ATAG_REVISION, parse_tag_revision);
+
+static int __init parse_tag_cmdline(const struct tag *tag)
+{
+#if defined(CONFIG_CMDLINE_EXTEND)
+	strlcat(default_command_line, " ", COMMAND_LINE_SIZE);
+	strlcat(default_command_line, tag->u.cmdline.cmdline,
+		COMMAND_LINE_SIZE);
+#elif defined(CONFIG_CMDLINE_FORCE)
+	pr_warning("Ignoring tag cmdline (using the default kernel command line)\n");
+#else
+	strlcpy(default_command_line, tag->u.cmdline.cmdline,
+		COMMAND_LINE_SIZE);
+#endif
+	return 0;
+}
+
+__tagtable(ATAG_CMDLINE, parse_tag_cmdline);
+
+/*
+ * Scan the tag table for this tag, and call its parse function.
+ * The tag table is built by the linker from all the __tagtable
+ * declarations.
+ */
+static int __init parse_tag(const struct tag *tag)
+{
+	extern struct tagtable __tagtable_begin, __tagtable_end;
+	struct tagtable *t;
+
+	for (t = &__tagtable_begin; t < &__tagtable_end; t++)
+		if (tag->hdr.tag == t->tag) {
+			t->parse(tag);
+			break;
+		}
+
+	return t < &__tagtable_end;
+}
+
+/*
+ * Parse all tags in the list, checking both the global and architecture
+ * specific tag tables.
+ */
+static void __init parse_tags(const struct tag *t)
+{
+	for (; t->hdr.size; t = tag_next(t))
+		if (!parse_tag(t))
+			printk(KERN_WARNING
+				"Ignoring unrecognised tag 0x%08x\n",
+				t->hdr.tag);
+}
+
+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;
+}
+
+struct machine_desc * __init setup_machine_tags(phys_addr_t __atags_pointer,
+						unsigned int machine_nr)
+{
+	struct tag *tags = (struct tag *)&default_tags;
+	struct machine_desc *mdesc = NULL, *p;
+	char *from = default_command_line;
+
+	default_tags.mem.start = PHYS_OFFSET;
+
+	/*
+	 * locate machine in the list of supported machines.
+	 */
+	for_each_machine_desc(p)
+		if (machine_nr == p->nr) {
+			printk("Machine: %s\n", p->name);
+			mdesc = p;
+			break;
+		}
+
+	if (!mdesc) {
+		early_print("\nError: unrecognized/unsupported machine ID"
+			    " (r1 = 0x%08x).\n\n", machine_nr);
+		dump_machine_table(); /* does not return */
+	}
+	
+	if (__atags_pointer)
+		tags = phys_to_virt(__atags_pointer);
+	else if (mdesc->atag_offset)
+		tags = (void *)(PAGE_OFFSET + mdesc->atag_offset);
+
+#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) {
+		early_print("Warning: Neither atags nor dtb found\n");
+		tags = (struct tag *)&default_tags;
+	}
+
+	if (mdesc->fixup)
+		mdesc->fixup(tags, &from, &meminfo);
+
+	if (tags->hdr.tag == ATAG_CORE) {
+		if (meminfo.nr_banks != 0)
+			squash_mem_tags(tags);
+		save_atags(tags);
+		parse_tags(tags);
+	}
+
+	/* parse_early_param needs a boot_command_line */
+	strlcpy(boot_command_line, from, COMMAND_LINE_SIZE);
+
+	return mdesc;
+}
diff --git a/arch/arm/kernel/atags.c b/arch/arm/kernel/atags_proc.c
similarity index 100%
rename from arch/arm/kernel/atags.c
rename to arch/arm/kernel/atags_proc.c
diff --git a/arch/arm/kernel/compat.h b/arch/arm/kernel/compat.h
deleted file mode 100644
index 39264ab1b9..0000000000
--- a/arch/arm/kernel/compat.h
+++ /dev/null
@@ -1,11 +0,0 @@
-/*
- *  linux/arch/arm/kernel/compat.h
- *
- *  Copyright (C) 2001 Russell King
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
-*/
-
-extern void convert_to_tag_list(struct tag *tags);
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index a81dcecc73..0785472460 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -21,11 +21,9 @@
 #include <linux/init.h>
 #include <linux/kexec.h>
 #include <linux/of_fdt.h>
-#include <linux/root_dev.h>
 #include <linux/cpu.h>
 #include <linux/interrupt.h>
 #include <linux/smp.h>
-#include <linux/fs.h>
 #include <linux/proc_fs.h>
 #include <linux/memblock.h>
 #include <linux/bug.h>
@@ -56,15 +54,9 @@
 #include <asm/unwind.h>
 #include <asm/memblock.h>
 
-#if defined(CONFIG_DEPRECATED_PARAM_STRUCT)
-#include "compat.h"
-#endif
 #include "atags.h"
 #include "tcm.h"
 
-#ifndef MEM_SIZE
-#define MEM_SIZE	(16*1024*1024)
-#endif
 
 #if defined(CONFIG_FPE_NWFPE) || defined(CONFIG_FPE_FASTFPE)
 char fpe_type[8];
@@ -145,7 +137,6 @@ static const char *machine_name;
 static char __initdata cmd_line[COMMAND_LINE_SIZE];
 struct machine_desc *machine_desc __initdata;
 
-static char default_command_line[COMMAND_LINE_SIZE] __initdata = CONFIG_CMDLINE;
 static union { char c[4]; unsigned long l; } endian_test __initdata = { { 'l', '?', '?', 'b' } };
 #define ENDIANNESS ((char)endian_test.l)
 
@@ -583,21 +574,6 @@ static int __init early_mem(char *p)
 }
 early_param("mem", early_mem);
 
-static void __init
-setup_ramdisk(int doload, int prompt, int image_start, unsigned int rd_sz)
-{
-#ifdef CONFIG_BLK_DEV_RAM
-	extern int rd_size, rd_image_start, rd_prompt, rd_doload;
-
-	rd_image_start = image_start;
-	rd_prompt = prompt;
-	rd_doload = doload;
-
-	if (rd_sz)
-		rd_size = rd_sz;
-#endif
-}
-
 static void __init request_standard_resources(struct machine_desc *mdesc)
 {
 	struct memblock_region *region;
@@ -643,35 +619,6 @@ static void __init request_standard_resources(struct machine_desc *mdesc)
 		request_resource(&ioport_resource, &lp2);
 }
 
-/*
- *  Tag parsing.
- *
- * This is the new way of passing data to the kernel at boot time.  Rather
- * than passing a fixed inflexible structure to the kernel, we pass a list
- * of variable-sized tags to the kernel.  The first tag must be a ATAG_CORE
- * tag for the list to be recognised (to distinguish the tagged list from
- * a param_struct).  The list is terminated with a zero-length tag (this tag
- * is not parsed in any way).
- */
-static int __init parse_tag_core(const struct tag *tag)
-{
-	if (tag->hdr.size > 2) {
-		if ((tag->u.core.flags & 1) == 0)
-			root_mountflags &= ~MS_RDONLY;
-		ROOT_DEV = old_decode_dev(tag->u.core.rootdev);
-	}
-	return 0;
-}
-
-__tagtable(ATAG_CORE, parse_tag_core);
-
-static int __init parse_tag_mem32(const struct tag *tag)
-{
-	return arm_add_memory(tag->u.mem.start, tag->u.mem.size);
-}
-
-__tagtable(ATAG_MEM, parse_tag_mem32);
-
 #if defined(CONFIG_VGA_CONSOLE) || defined(CONFIG_DUMMY_CONSOLE)
 struct screen_info screen_info = {
  .orig_video_lines	= 30,
@@ -681,117 +628,8 @@ struct screen_info screen_info = {
  .orig_video_isVGA	= 1,
  .orig_video_points	= 8
 };
-
-static int __init parse_tag_videotext(const struct tag *tag)
-{
-	screen_info.orig_x            = tag->u.videotext.x;
-	screen_info.orig_y            = tag->u.videotext.y;
-	screen_info.orig_video_page   = tag->u.videotext.video_page;
-	screen_info.orig_video_mode   = tag->u.videotext.video_mode;
-	screen_info.orig_video_cols   = tag->u.videotext.video_cols;
-	screen_info.orig_video_ega_bx = tag->u.videotext.video_ega_bx;
-	screen_info.orig_video_lines  = tag->u.videotext.video_lines;
-	screen_info.orig_video_isVGA  = tag->u.videotext.video_isvga;
-	screen_info.orig_video_points = tag->u.videotext.video_points;
-	return 0;
-}
-
-__tagtable(ATAG_VIDEOTEXT, parse_tag_videotext);
 #endif
 
-static int __init parse_tag_ramdisk(const struct tag *tag)
-{
-	setup_ramdisk((tag->u.ramdisk.flags & 1) == 0,
-		      (tag->u.ramdisk.flags & 2) == 0,
-		      tag->u.ramdisk.start, tag->u.ramdisk.size);
-	return 0;
-}
-
-__tagtable(ATAG_RAMDISK, parse_tag_ramdisk);
-
-static int __init parse_tag_serialnr(const struct tag *tag)
-{
-	system_serial_low = tag->u.serialnr.low;
-	system_serial_high = tag->u.serialnr.high;
-	return 0;
-}
-
-__tagtable(ATAG_SERIAL, parse_tag_serialnr);
-
-static int __init parse_tag_revision(const struct tag *tag)
-{
-	system_rev = tag->u.revision.rev;
-	return 0;
-}
-
-__tagtable(ATAG_REVISION, parse_tag_revision);
-
-static int __init parse_tag_cmdline(const struct tag *tag)
-{
-#if defined(CONFIG_CMDLINE_EXTEND)
-	strlcat(default_command_line, " ", COMMAND_LINE_SIZE);
-	strlcat(default_command_line, tag->u.cmdline.cmdline,
-		COMMAND_LINE_SIZE);
-#elif defined(CONFIG_CMDLINE_FORCE)
-	pr_warning("Ignoring tag cmdline (using the default kernel command line)\n");
-#else
-	strlcpy(default_command_line, tag->u.cmdline.cmdline,
-		COMMAND_LINE_SIZE);
-#endif
-	return 0;
-}
-
-__tagtable(ATAG_CMDLINE, parse_tag_cmdline);
-
-/*
- * Scan the tag table for this tag, and call its parse function.
- * The tag table is built by the linker from all the __tagtable
- * declarations.
- */
-static int __init parse_tag(const struct tag *tag)
-{
-	extern struct tagtable __tagtable_begin, __tagtable_end;
-	struct tagtable *t;
-
-	for (t = &__tagtable_begin; t < &__tagtable_end; t++)
-		if (tag->hdr.tag == t->tag) {
-			t->parse(tag);
-			break;
-		}
-
-	return t < &__tagtable_end;
-}
-
-/*
- * Parse all tags in the list, checking both the global and architecture
- * specific tag tables.
- */
-static void __init parse_tags(const struct tag *t)
-{
-	for (; t->hdr.size; t = tag_next(t))
-		if (!parse_tag(t))
-			printk(KERN_WARNING
-				"Ignoring unrecognised tag 0x%08x\n",
-				t->hdr.tag);
-}
-
-/*
- * This holds our defaults.
- */
-static struct init_tags {
-	struct tag_header hdr1;
-	struct tag_core   core;
-	struct tag_header hdr2;
-	struct tag_mem32  mem;
-	struct tag_header hdr3;
-} init_tags __initdata = {
-	{ tag_size(tag_core), ATAG_CORE },
-	{ 1, PAGE_SIZE, 0xff },
-	{ tag_size(tag_mem32), ATAG_MEM },
-	{ MEM_SIZE },
-	{ 0, ATAG_NONE }
-};
-
 static int __init customize_machine(void)
 {
 	/* customizes platform devices, or adds new ones */
@@ -858,78 +696,6 @@ static void __init reserve_crashkernel(void)
 static inline void reserve_crashkernel(void) {}
 #endif /* CONFIG_KEXEC */
 
-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;
-}
-
-static struct machine_desc * __init setup_machine_tags(unsigned int nr)
-{
-	struct tag *tags = (struct tag *)&init_tags;
-	struct machine_desc *mdesc = NULL, *p;
-	char *from = default_command_line;
-
-	init_tags.mem.start = PHYS_OFFSET;
-
-	/*
-	 * locate machine in the list of supported machines.
-	 */
-	for_each_machine_desc(p)
-		if (nr == p->nr) {
-			printk("Machine: %s\n", p->name);
-			mdesc = p;
-			break;
-		}
-
-	if (!mdesc) {
-		early_print("\nError: unrecognized/unsupported machine ID"
-			" (r1 = 0x%08x).\n\n", nr);
-		dump_machine_table(); /* does not return */
-	}
-
-	if (__atags_pointer)
-		tags = phys_to_virt(__atags_pointer);
-	else if (mdesc->atag_offset)
-		tags = (void *)(PAGE_OFFSET + mdesc->atag_offset);
-
-#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) {
-#if defined(CONFIG_OF)
-		/*
-		 * If CONFIG_OF is set, then assume this is a reasonably
-		 * modern system that should pass boot parameters
-		 */
-		early_print("Warning: Neither atags nor dtb found\n");
-#endif
-		tags = (struct tag *)&init_tags;
-	}
-
-	if (mdesc->fixup)
-		mdesc->fixup(tags, &from, &meminfo);
-
-	if (tags->hdr.tag == ATAG_CORE) {
-		if (meminfo.nr_banks != 0)
-			squash_mem_tags(tags);
-		save_atags(tags);
-		parse_tags(tags);
-	}
-
-	/* parse_early_param needs a boot_command_line */
-	strlcpy(boot_command_line, from, COMMAND_LINE_SIZE);
-
-	return mdesc;
-}
-
 static int __init meminfo_cmp(const void *_a, const void *_b)
 {
 	const struct membank *a = _a, *b = _b;
@@ -944,7 +710,7 @@ void __init setup_arch(char **cmdline_p)
 	setup_processor();
 	mdesc = setup_machine_fdt(__atags_pointer);
 	if (!mdesc)
-		mdesc = setup_machine_tags(machine_arch_type);
+		mdesc = setup_machine_tags(__atags_pointer, machine_arch_type);
 	machine_desc = mdesc;
 	machine_name = mdesc->name;
 
-- 
1.7.12.84.gefa6462

[PATCH 2/2] ARM: allow for ATAGS to be configured out when DT support is selected

[Nicolas Pitre]

Now that ATAGS support is well contained, we can easily remove it from
the kernel build if so desired.  It has to explicitly be disabled, and
only when DT support is selected.

Note: disabling kernel ATAGS support does not prevent the usage of
CONFIG_ARM_ATAG_DTB_COMPAT.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
---
 arch/arm/Kconfig         | 26 +++++++++++++++++++-------
 arch/arm/kernel/Makefile |  5 +++--
 arch/arm/kernel/atags.h  | 11 +++++++++++
 3 files changed, 33 insertions(+), 9 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index c5f9ae5dbd..5c7302e208 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1891,12 +1891,6 @@ config CC_STACKPROTECTOR
 	  neutralized via a kernel panic.
 	  This feature requires gcc version 4.2 or above.
 
-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"
@@ -1909,6 +1903,23 @@ config USE_OF
 	help
 	  Include support for flattened device tree machine descriptions.
 
+config ATAGS
+	bool "Support for the traditional ATAGS boot data passing" if USE_OF
+	default y
+	help
+	  This is the traditional way of passing data to the kernel at boot
+	  time. If you are solely relying on the flattened device tree (or
+	  the ARM_ATAG_DTB_COMPAT option) then you may unselect this option
+	  to remove ATAGS support from your kernel binary.  If unsure,
+	  leave this to y.
+
+config DEPRECATED_PARAM_STRUCT
+	bool "Provide old way to pass kernel parameters"
+	depends on ATAGS
+	help
+	  This was deprecated in 2001 and announced to live on for 5 years.
+	  Some old boot loaders still use this way.
+
 # Compressed boot loader in ROM.  Yes, we really want to ask about
 # TEXT and BSS so we preserve their values in the config files.
 config ZBOOT_ROM_TEXT
@@ -2035,6 +2046,7 @@ config CMDLINE
 choice
 	prompt "Kernel command line type" if CMDLINE != ""
 	default CMDLINE_FROM_BOOTLOADER
+	depends on ATAGS
 
 config CMDLINE_FROM_BOOTLOADER
 	bool "Use bootloader kernel arguments if available"
@@ -2104,7 +2116,7 @@ config KEXEC
 
 config ATAGS_PROC
 	bool "Export atags in procfs"
-	depends on KEXEC
+	depends on ATAGS && KEXEC
 	default y
 	help
 	  Should the atags used to boot the kernel be exported in an "atags"
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index 086c9d3bc3..79e346a5d7 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -15,10 +15,12 @@ CFLAGS_REMOVE_return_address.o = -pg
 
 # Object file lists.
 
-obj-y		:= atags_parse.o elf.o entry-armv.o entry-common.o irq.o opcodes.o \
+obj-y		:= elf.o entry-armv.o entry-common.o irq.o opcodes.o \
 		   process.o ptrace.o return_address.o sched_clock.o \
 		   setup.o signal.o stacktrace.o sys_arm.o time.o traps.o
 
+obj-$(CONFIG_ATAGS)		+= atags_parse.o
+obj-$(CONFIG_ATAGS_PROC)	+= atags_proc.o
 obj-$(CONFIG_DEPRECATED_PARAM_STRUCT) += atags_compat.o
 
 obj-$(CONFIG_LEDS)		+= leds.o
@@ -52,7 +54,6 @@ test-kprobes-objs		+= kprobes-test-thumb.o
 else
 test-kprobes-objs		+= kprobes-test-arm.o
 endif
-obj-$(CONFIG_ATAGS_PROC)	+= atags_proc.o
 obj-$(CONFIG_OABI_COMPAT)	+= sys_oabi-compat.o
 obj-$(CONFIG_ARM_THUMBEE)	+= thumbee.o
 obj-$(CONFIG_KGDB)		+= kgdb.o
diff --git a/arch/arm/kernel/atags.h b/arch/arm/kernel/atags.h
index a888fdd381..9edc969233 100644
--- a/arch/arm/kernel/atags.h
+++ b/arch/arm/kernel/atags.h
@@ -5,4 +5,15 @@ static inline void save_atags(struct tag *tags) { }
 #endif
 
 void convert_to_tag_list(struct tag *tags);
+
+#ifdef CONFIG_ATAGS
 struct machine_desc *setup_machine_tags(phys_addr_t __atags_pointer, unsigned int machine_nr);
+#else
+static inline struct machine_desc *
+setup_machine_tags(phys_addr_t __atags_pointer, unsigned int machine_nr)
+{
+	early_print("no ATAGS support: can't continue\n");
+	while (true);
+	unreachable();
+}
+#endif
-- 
1.7.12.84.gefa6462

[PATCH 2/2] ARM: allow for ATAGS to be configured out when DT support is selected

[Linus Walleij]

On Thu, Aug 30, 2012 at 11:10 PM, Nicolas Pitre
<nicolas.pitre@linaro.org> wrote:

> Now that ATAGS support is well contained, we can easily remove it from
> the kernel build if so desired.  It has to explicitly be disabled, and
> only when DT support is selected.

I patched this on top of my Integrator patch stack and disabled
the ATAGS, it just works.

Tested-by: Linus Walleij <linus.walleij@linaro.org>

I'd suggest you to put this into Russells tracker then?

Yours,
Linus Walleij

[PATCH 2/2] ARM: allow for ATAGS to be configured out when DT support is selected

[Nicolas Pitre]

On Sat, 1 Sep 2012, Linus Walleij wrote:

> On Thu, Aug 30, 2012 at 11:10 PM, Nicolas Pitre
> <nicolas.pitre@linaro.org> wrote:
> 
> > Now that ATAGS support is well contained, we can easily remove it from
> > the kernel build if so desired.  It has to explicitly be disabled, and
> > only when DT support is selected.
> 
> I patched this on top of my Integrator patch stack and disabled
> the ATAGS, it just works.
> 
> Tested-by: Linus Walleij <linus.walleij@linaro.org>

Thanks.

> I'd suggest you to put this into Russells tracker then?

Certainly.  I just wanted someone else than myself to test it / look at it 
before I do so.


Nicolas

[PATCH 2/2] ARM: allow for ATAGS to be configured out when DT support is selected

[Arnd Bergmann]

On Thursday 30 August 2012, Nicolas Pitre wrote:
> Now that ATAGS support is well contained, we can easily remove it from
> the kernel build if so desired.  It has to explicitly be disabled, and
> only when DT support is selected.
> 
> Note: disabling kernel ATAGS support does not prevent the usage of
> CONFIG_ARM_ATAG_DTB_COMPAT.

> ...

> +config ATAGS
> +	bool "Support for the traditional ATAGS boot data passing" if USE_OF
> +	default y
> +	help
> +	  This is the traditional way of passing data to the kernel at boot
> +	  time. If you are solely relying on the flattened device tree (or
> +	  the ARM_ATAG_DTB_COMPAT option) then you may unselect this option
> +	  to remove ATAGS support from your kernel binary.  If unsure,
> +	  leave this to y.

That's a clever way of implementing it, I had not though of making it an
optional default-y symbol.

Acked-by: Arnd Bergmann <arnd@arndb.de>

Should we do patches to the individual platforms bsaed on this to disable
the ATAG based board files when CONFIG_ATAG is disabled?

	Arnd

[PATCH 2/2] ARM: allow for ATAGS to be configured out when DT support is selected

[Will Deacon]

On Thu, Aug 30, 2012 at 10:10:08PM +0100, Nicolas Pitre wrote:
> Now that ATAGS support is well contained, we can easily remove it from
> the kernel build if so desired.  It has to explicitly be disabled, and
> only when DT support is selected.
> 
> Note: disabling kernel ATAGS support does not prevent the usage of
> CONFIG_ARM_ATAG_DTB_COMPAT.
> 
> Signed-off-by: Nicolas Pitre <nico@linaro.org>
> ---
>  arch/arm/Kconfig         | 26 +++++++++++++++++++-------
>  arch/arm/kernel/Makefile |  5 +++--
>  arch/arm/kernel/atags.h  | 11 +++++++++++
>  3 files changed, 33 insertions(+), 9 deletions(-)
> 
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index c5f9ae5dbd..5c7302e208 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -1891,12 +1891,6 @@ config CC_STACKPROTECTOR
>  	  neutralized via a kernel panic.
>  	  This feature requires gcc version 4.2 or above.
>  
> -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

Since you're in this area, do we need to carry this forward? If somebody is
using it then obviously we have to keep it but it might be worth asking
around.

Back on topic, this looks good to me:

Acked-by: Will Deacon <will.deacon@arm.com>

Will

[PATCH 2/2] ARM: allow for ATAGS to be configured out when DT support is selected

[Nicolas Pitre]

On Sun, 2 Sep 2012, Will Deacon wrote:

> On Thu, Aug 30, 2012 at 10:10:08PM +0100, Nicolas Pitre wrote:
> > Now that ATAGS support is well contained, we can easily remove it from
> > the kernel build if so desired.  It has to explicitly be disabled, and
> > only when DT support is selected.
> > 
> > Note: disabling kernel ATAGS support does not prevent the usage of
> > CONFIG_ARM_ATAG_DTB_COMPAT.
> > 
> > Signed-off-by: Nicolas Pitre <nico@linaro.org>
> > ---
> >  arch/arm/Kconfig         | 26 +++++++++++++++++++-------
> >  arch/arm/kernel/Makefile |  5 +++--
> >  arch/arm/kernel/atags.h  | 11 +++++++++++
> >  3 files changed, 33 insertions(+), 9 deletions(-)
> > 
> > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> > index c5f9ae5dbd..5c7302e208 100644
> > --- a/arch/arm/Kconfig
> > +++ b/arch/arm/Kconfig
> > @@ -1891,12 +1891,6 @@ config CC_STACKPROTECTOR
> >  	  neutralized via a kernel panic.
> >  	  This feature requires gcc version 4.2 or above.
> >  
> > -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
> 
> Since you're in this area, do we need to carry this forward? If somebody is
> using it then obviously we have to keep it but it might be worth asking
> around.

That should be a separate patch if that has to be dropped.  Right now 
that code is already in a file of its own and not getting in the way of 
anything else, and I didn't want to change any behavior on legacy 
platforms.

> Back on topic, this looks good to me:
> 
> Acked-by: Will Deacon <will.deacon@arm.com>

Thanks.


Nicolas

[PATCH 2/2] ARM: allow for ATAGS to be configured out when DT support is selected

[Nicolas Pitre]

On Sat, 1 Sep 2012, Arnd Bergmann wrote:

> On Thursday 30 August 2012, Nicolas Pitre wrote:
> > Now that ATAGS support is well contained, we can easily remove it from
> > the kernel build if so desired.  It has to explicitly be disabled, and
> > only when DT support is selected.
> > 
> > Note: disabling kernel ATAGS support does not prevent the usage of
> > CONFIG_ARM_ATAG_DTB_COMPAT.
> 
> > ...
> 
> > +config ATAGS
> > +	bool "Support for the traditional ATAGS boot data passing" if USE_OF
> > +	default y
> > +	help
> > +	  This is the traditional way of passing data to the kernel at boot
> > +	  time. If you are solely relying on the flattened device tree (or
> > +	  the ARM_ATAG_DTB_COMPAT option) then you may unselect this option
> > +	  to remove ATAGS support from your kernel binary.  If unsure,
> > +	  leave this to y.
> 
> That's a clever way of implementing it, I had not though of making it an
> optional default-y symbol.
> 
> Acked-by: Arnd Bergmann <arnd@arndb.de>

Thanks.

> Should we do patches to the individual platforms bsaed on this to disable
> the ATAG based board files when CONFIG_ATAG is disabled?

Well... that could be a good thing to make them depend on ATAGS indeed.  
But that can be done incrementally in later patches.


Nicolas

[PATCH 2/2] ARM: allow for ATAGS to be configured out when DT support is selected

[Olof Johansson]

On Thu, Aug 30, 2012 at 05:10:08PM -0400, Nicolas Pitre wrote:
> Now that ATAGS support is well contained, we can easily remove it from
> the kernel build if so desired.  It has to explicitly be disabled, and
> only when DT support is selected.
> 
> Note: disabling kernel ATAGS support does not prevent the usage of
> CONFIG_ARM_ATAG_DTB_COMPAT.
> 
> Signed-off-by: Nicolas Pitre <nico@linaro.org>

Nice!

Acked-by: Olof Johansson <olof@lixom.net>


-Olof