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[ARM] 4736/1: Export atags to userspace and allow kexec to use customised atags

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Currently, the atags used by kexec are fixed to the ones originally used
to boot the kernel. This is less than ideal as changing the commandline,
initrd and other options would be a useful feature.

This patch exports the atags used for the current kernel to userspace
through an "atags" file in procfs. The presence of the file is
controlled by its own Kconfig option and cleans up several ifdef blocks
into a separate file. The tags for the new kernel are assumed to be at
a fixed location before the kernel image itself. The location of the
tags used to boot the original kernel is unimportant and no longer
saved.

Based on a patch from Uli Luckas <u.luckas@road.de>

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Acked-by: Uli Luckas <u.luckas@road.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Richard Purdie
2008-01-02 00:56:46 +01:00
committed by Russell King
parent ae9458d6a0
commit 4cd9d6f774
8 changed files with 110 additions and 56 deletions
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32
arch/arm/kernel/setup.c
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@@ -24,7 +24,6 @@
#include <linux/interrupt.h>
#include <linux/smp.h>
#include <linux/fs.h>
#include <linux/kexec.h>
#include <asm/cpu.h>
#include <asm/elf.h>
@@ -39,6 +38,7 @@
#include <asm/mach/time.h>
#include "compat.h"
#include "atags.h"
#ifndef MEM_SIZE
#define MEM_SIZE (16*1024*1024)
@@ -784,23 +784,6 @@ static int __init customize_machine(void)
}
arch_initcall(customize_machine);
#ifdef CONFIG_KEXEC
/* Physical addr of where the boot params should be for this machine */
extern unsigned long kexec_boot_params_address;
/* Physical addr of the buffer into which the boot params are copied */
extern unsigned long kexec_boot_params_copy;
/* Pointer to the boot params buffer, for manipulation and display */
unsigned long kexec_boot_params;
EXPORT_SYMBOL(kexec_boot_params);
/* The buffer itself - make sure it is sized correctly */
static unsigned long kexec_boot_params_buf[(KEXEC_BOOT_PARAMS_SIZE + 3) / 4];
#endif
void __init setup_arch(char **cmdline_p)
{
struct tag *tags = (struct tag *)&init_tags;
@@ -819,18 +802,6 @@ void __init setup_arch(char **cmdline_p)
else if (mdesc->boot_params)
tags = phys_to_virt(mdesc->boot_params);
#ifdef CONFIG_KEXEC
kexec_boot_params_copy = virt_to_phys(kexec_boot_params_buf);
kexec_boot_params = (unsigned long)kexec_boot_params_buf;
if (__atags_pointer) {
kexec_boot_params_address = __atags_pointer;
memcpy((void *)kexec_boot_params, tags, KEXEC_BOOT_PARAMS_SIZE);
} else if (mdesc->boot_params) {
kexec_boot_params_address = mdesc->boot_params;
memcpy((void *)kexec_boot_params, tags, KEXEC_BOOT_PARAMS_SIZE);
}
#endif
/*
* If we have the old style parameters, convert them to
* a tag list.
@@ -846,6 +817,7 @@ void __init setup_arch(char **cmdline_p)
if (tags->hdr.tag == ATAG_CORE) {
if (meminfo.nr_banks != 0)
squash_mem_tags(tags);
save_atags(tags);
parse_tags(tags);
}