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411 lines
12 KiB
411 lines
12 KiB
From: Eric Piel <piel@localhost.(none)>
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Subject: [PATCH 1/1] ACPI: initramfs DSDT override support
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Patch-mainline: not yet
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Permits to load of DSDT (the main ACPI table) from initramfs. In case this
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option is selected, the initramfs is parsed at ACPI initialization (very early
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boot time) to look for a file DSDT.aml . This aims at allowing users to
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override the DSDT without recompiling the kernel. This is done by adding a new
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feature to the initramfs parser so that one specific file can be directly
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copied into memory.
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This is derived from the patch v0.8 from http://gaugusch.at/kernel.shtml but
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with kernel inclusion in mind: some clean-up's in the documentation, default
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set to No, a kernel parameter to disable it at runtime, and most important, a
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different approach for reading the initramfs which avoids using the filesystem
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infrastructure.
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It also contains a fix for compilation on non-ACPI platforms provided by Rene Rebe.
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Update 17 Sep 2009 jeffm@suse.com:
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- 2.6.30 (or so) introduced very early ACPI initialization for proper SMP
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detection. This caused crashes since things like the mm caches weren't
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set up yet, so kmalloc would crash. This update delays overriding the DSDT
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until the acpi_early_init() call that used to override it. Since there is
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a DSDT already loaded, it is necessarily a bit hacky.
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Signed-off-by: Eric Piel <eric.piel@tremplin-utc.net>
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Signed-off-by: Thomas Renninger <trenn@suse.de>
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Signed-off-by: Len Brown <len.brown@intel.com>
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Signed-off-by: Jeff Mahoney <jeffm@suse.com>
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---
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Documentation/acpi/dsdt-override.txt | 12 +++-
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Documentation/acpi/initramfs-add-dsdt.sh | 43 +++++++++++++++
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Documentation/kernel-parameters.txt | 3 +
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drivers/acpi/Kconfig | 11 ++++
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drivers/acpi/acpica/tbxface.c | 36 +++++++++++--
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drivers/acpi/osl.c | 28 +++++++++-
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init/initramfs.c | 84 +++++++++++++++++++++++++++++++
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7 files changed, 209 insertions(+), 8 deletions(-)
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create mode 100644 Documentation/acpi/initramfs-add-dsdt.sh
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--- a/Documentation/acpi/dsdt-override.txt
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+++ b/Documentation/acpi/dsdt-override.txt
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@@ -1,7 +1,15 @@
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-Linux supports a method of overriding the BIOS DSDT:
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+Linux supports two methods of overriding the BIOS DSDT:
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CONFIG_ACPI_CUSTOM_DSDT builds the image into the kernel.
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-When to use this method is described in detail on the
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+CONFIG_ACPI_CUSTOM_DSDT_INITRD adds the image to the initrd.
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+
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+When to use these methods is described in detail on the
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Linux/ACPI home page:
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http://www.lesswatts.org/projects/acpi/overridingDSDT.php
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+
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+Note that if both options are used, the DSDT supplied
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+by the INITRD method takes precedence.
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+
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+Documentation/initramfs-add-dsdt.sh is provided for convenience
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+for use with the CONFIG_ACPI_CUSTOM_DSDT_INITRD method.
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--- /dev/null
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+++ b/Documentation/acpi/initramfs-add-dsdt.sh
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@@ -0,0 +1,43 @@
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+#!/bin/bash
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+# Adds a DSDT file to the initrd (if it's an initramfs)
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+# first argument is the name of archive
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+# second argument is the name of the file to add
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+# The file will be copied as /DSDT.aml
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+
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+# 20060126: fix "Premature end of file" with some old cpio (Roland Robic)
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+# 20060205: this time it should really work
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+
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+# check the arguments
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+if [ $# -ne 2 ]; then
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+ program_name=$(basename $0)
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+ echo "\
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+$program_name: too few arguments
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+Usage: $program_name initrd-name.img DSDT-to-add.aml
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+Adds a DSDT file to an initrd (in initramfs format)
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+
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+ initrd-name.img: filename of the initrd in initramfs format
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+ DSDT-to-add.aml: filename of the DSDT file to add
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+ " 1>&2
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+ exit 1
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+fi
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+
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+# we should check it's an initramfs
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+
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+tempcpio=$(mktemp -d)
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+# cleanup on exit, hangup, interrupt, quit, termination
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+trap 'rm -rf $tempcpio' 0 1 2 3 15
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+
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+# extract the archive
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+gunzip -c "$1" > "$tempcpio"/initramfs.cpio || exit 1
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+
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+# copy the DSDT file at the root of the directory so that we can call it "/DSDT.aml"
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+cp -f "$2" "$tempcpio"/DSDT.aml
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+
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+# add the file
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+cd "$tempcpio"
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+(echo DSDT.aml | cpio --quiet -H newc -o -A -O "$tempcpio"/initramfs.cpio) || exit 1
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+cd "$OLDPWD"
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+
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+# re-compress the archive
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+gzip -c "$tempcpio"/initramfs.cpio > "$1"
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+
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--- a/Documentation/kernel-parameters.txt
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+++ b/Documentation/kernel-parameters.txt
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@@ -217,6 +217,9 @@ and is between 256 and 4096 characters.
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acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
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+ acpi_no_initrd_override [KNL,ACPI]
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+ Disable loading custom ACPI tables from the initramfs
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+
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acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
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Format: To spoof as Windows 98: ="Microsoft Windows"
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--- a/drivers/acpi/Kconfig
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+++ b/drivers/acpi/Kconfig
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@@ -248,6 +248,17 @@ config ACPI_CUSTOM_DSDT
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bool
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default ACPI_CUSTOM_DSDT_FILE != ""
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+config ACPI_CUSTOM_DSDT_INITRD
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+ bool "Read Custom DSDT from initramfs"
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+ depends on BLK_DEV_INITRD
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+ default n
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+ help
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+ This option supports a custom DSDT by optionally loading it from initrd.
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+ See Documentation/acpi/dsdt-override.txt
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+
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+ If you are not using this feature now, but may use it later,
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+ it is safe to say Y here.
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+
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config ACPI_BLACKLIST_YEAR
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int "Disable ACPI for systems before Jan 1st this year" if X86_32
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default 0
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--- a/drivers/acpi/acpica/tbxface.c
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+++ b/drivers/acpi/acpica/tbxface.c
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@@ -484,6 +484,33 @@ acpi_get_table_by_index(u32 table_index,
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ACPI_EXPORT_SYMBOL(acpi_get_table_by_index)
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+static void
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+acpi_dsdt_initrd_override(void)
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+{
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+#if defined(CONFIG_ACPI_CUSTOM_DSDT_INITRD)
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+ struct acpi_table_header *new = NULL;
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+ struct acpi_table_desc *table;
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+ acpi_status status;
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+
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+ table = &acpi_gbl_root_table_list.tables[ACPI_TABLE_INDEX_DSDT];
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+ status = acpi_os_table_override(table->pointer, &new);
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+ if (ACPI_SUCCESS(status) && new) {
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+ acpi_tb_delete_table(table);
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+
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+ /* This is the top part of acpi_table_load */
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+ memset(table, 0, sizeof(*table));
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+ table->address = ACPI_PTR_TO_PHYSADDR(new);
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+ table->pointer = new;
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+ table->length = new->length;
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+ table->flags |= ACPI_TABLE_ORIGIN_OVERRIDE;
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+ table->flags |= ACPI_TABLE_ORIGIN_ALLOCATED;
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+ memcpy(table->signature.ascii, new->signature, ACPI_NAME_SIZE);
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+ acpi_tb_print_table_header(table->address, new);
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+ }
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+#endif
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+}
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+
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+
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/*******************************************************************************
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*
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* FUNCTION: acpi_tb_load_namespace
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@@ -496,7 +523,7 @@ ACPI_EXPORT_SYMBOL(acpi_get_table_by_ind
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* the RSDT/XSDT.
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*
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******************************************************************************/
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-static acpi_status acpi_tb_load_namespace(void)
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+static acpi_status __init acpi_tb_load_namespace(void)
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{
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acpi_status status;
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u32 i;
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@@ -522,6 +549,8 @@ static acpi_status acpi_tb_load_namespac
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goto unlock_and_exit;
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}
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+ acpi_dsdt_initrd_override();
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+
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/* A valid DSDT is required */
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status =
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@@ -590,7 +619,7 @@ static acpi_status acpi_tb_load_namespac
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*
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******************************************************************************/
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-acpi_status acpi_load_tables(void)
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+acpi_status __init acpi_load_tables(void)
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{
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acpi_status status;
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@@ -607,9 +636,6 @@ acpi_status acpi_load_tables(void)
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return_ACPI_STATUS(status);
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}
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-ACPI_EXPORT_SYMBOL(acpi_load_tables)
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-
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-
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/*******************************************************************************
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*
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* FUNCTION: acpi_install_table_handler
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--- a/drivers/acpi/osl.c
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+++ b/drivers/acpi/osl.c
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@@ -98,6 +98,11 @@ static DEFINE_SPINLOCK(acpi_res_lock);
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#define OSI_STRING_LENGTH_MAX 64 /* arbitrary */
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static char osi_additional_string[OSI_STRING_LENGTH_MAX];
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+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
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+static int acpi_no_initrd_override;
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+extern struct acpi_table_header *acpi_find_dsdt_initrd(void);
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+#endif
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+
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/*
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* The story of _OSI(Linux)
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*
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@@ -352,7 +357,7 @@ acpi_os_predefined_override(const struct
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return AE_OK;
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}
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-acpi_status
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+acpi_status __init
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acpi_os_table_override(struct acpi_table_header * existing_table,
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struct acpi_table_header ** new_table)
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{
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@@ -365,6 +370,18 @@ acpi_os_table_override(struct acpi_table
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if (strncmp(existing_table->signature, "DSDT", 4) == 0)
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*new_table = (struct acpi_table_header *)AmlCode;
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#endif
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+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
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+ if ((strncmp(existing_table->signature, "DSDT", 4) == 0) &&
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+ !acpi_no_initrd_override && acpi_gbl_permanent_mmap) {
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+ /* JDM: acpi_gbl_permanent_mmap means acpi_early_init() has
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+ * been called so things like kmalloc are ok. */
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+ struct acpi_table_header *initrd_table;
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+
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+ initrd_table = acpi_find_dsdt_initrd();
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+ if (initrd_table)
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+ *new_table = initrd_table;
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+ }
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+#endif
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if (*new_table != NULL) {
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printk(KERN_WARNING PREFIX "Override [%4.4s-%8.8s], "
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"this is unsafe: tainting kernel\n",
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@@ -375,6 +392,15 @@ acpi_os_table_override(struct acpi_table
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return AE_OK;
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}
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+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
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+static int __init acpi_no_initrd_override_setup(char *s)
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+{
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+ acpi_no_initrd_override = 1;
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+ return 1;
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+}
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+__setup("acpi_no_initrd_override", acpi_no_initrd_override_setup);
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+#endif
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+
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static irqreturn_t acpi_irq(int irq, void *dev_id)
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{
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u32 handled;
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--- a/init/initramfs.c
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+++ b/init/initramfs.c
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@@ -8,6 +8,9 @@
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#include <linux/dirent.h>
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#include <linux/syscalls.h>
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#include <linux/utime.h>
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+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
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+#include <acpi/acpi.h>
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+#endif
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static __initdata char *message;
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static void __init error(char *x)
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@@ -125,6 +128,12 @@ static __initdata unsigned long body_len
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static __initdata uid_t uid;
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static __initdata gid_t gid;
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static __initdata unsigned rdev;
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+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
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+static __initdata char *file_looked_for;
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+static __initdata struct acpi_table_header *file_mem;
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+#else
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+const char *file_looked_for = NULL;
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+#endif
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static void __init parse_header(char *s)
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{
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@@ -159,6 +168,7 @@ static __initdata enum state {
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SkipIt,
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GotName,
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CopyFile,
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+ CopyFileMem,
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GotSymlink,
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Reset
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} state, next_state;
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@@ -228,6 +238,11 @@ static int __init do_header(void)
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parse_header(collected);
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next_header = this_header + N_ALIGN(name_len) + body_len;
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next_header = (next_header + 3) & ~3;
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+ if (file_looked_for) {
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+ read_into(name_buf, N_ALIGN(name_len), GotName);
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+ return 0;
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+ }
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+
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state = SkipIt;
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if (name_len <= 0 || name_len > PATH_MAX)
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return 0;
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@@ -298,6 +313,12 @@ static int __init do_name(void)
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free_hash();
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return 0;
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}
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+ if (file_looked_for) {
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+ if (S_ISREG(mode) &&
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+ (strcmp(collected, file_looked_for) == 0))
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+ state = CopyFileMem;
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+ return 0;
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+ }
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clean_path(collected, mode);
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if (S_ISREG(mode)) {
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int ml = maybe_link();
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@@ -333,6 +354,40 @@ static int __init do_name(void)
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return 0;
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}
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+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
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+static int __init do_copy_mem(void)
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+{
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+ static void *file_current; /* current position in the memory */
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+ if (file_mem == NULL) {
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+ if (body_len < 4) { /* check especially against empty files */
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+ error("file is less than 4 bytes");
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+ return 1;
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+ }
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+ file_mem = kmalloc(body_len, GFP_ATOMIC);
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+ if (!file_mem) {
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+ error("failed to allocate enough memory");
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+ return 1;
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+ }
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+ file_current = file_mem;
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+ }
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+ if (count >= body_len) {
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+ memcpy(file_current, victim, body_len);
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+ eat(body_len);
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+ file_looked_for = NULL; /* don't find files with same name */
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+ state = SkipIt;
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+ return 0;
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+ } else {
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+ memcpy(file_current, victim, count);
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+ file_current += count;
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+ body_len -= count;
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+ eat(count);
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+ return 1;
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+ }
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+}
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+#else
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+#define do_copy_mem NULL
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+#endif
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+
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static int __init do_copy(void)
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{
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if (count >= body_len) {
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@@ -370,6 +425,7 @@ static __initdata int (*actions[])(void)
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[SkipIt] = do_skip,
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[GotName] = do_name,
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[CopyFile] = do_copy,
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+ [CopyFileMem] = do_copy_mem,
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[GotSymlink] = do_symlink,
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[Reset] = do_reset,
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};
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@@ -606,3 +662,31 @@ static int __init populate_rootfs(void)
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return 0;
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}
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rootfs_initcall(populate_rootfs);
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+
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+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
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+struct acpi_table_header * __init acpi_find_dsdt_initrd(void)
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+{
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+ char *err, *ramfs_dsdt_name = "DSDT.aml";
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+
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+ printk(KERN_INFO "ACPI: Checking initramfs for custom DSDT\n");
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+ file_mem = NULL;
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+ file_looked_for = ramfs_dsdt_name;
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+ err = unpack_to_rootfs((char *)initrd_start,
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+ initrd_end - initrd_start);
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+ file_looked_for = NULL;
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+
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+ if (err) {
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+ /*
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+ * Even if reading the DSDT file was successful,
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+ * we give up if the initramfs cannot be entirely read.
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+ */
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+ kfree(file_mem);
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+ printk(KERN_ERR "ACPI: Aborted because %s.\n", err);
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+ return NULL;
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+ }
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+ if (file_mem)
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+ printk(KERN_INFO "ACPI: Found DSDT in %s.\n", ramfs_dsdt_name);
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+
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+ return file_mem;
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+}
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+#endif
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