kernel26-magellan/patches-2.6.29-r8/0157-2.6.29-acpi-dsdt-initrd-0.9c.patch

ACPI: initramfs DSDT override support

Permits to load of DSDT (the main ACPI table) from initramfs. In case this
option is selected, the initramfs is parsed at ACPI initialization (very early
boot time) to look for a file called "DSDT.aml". This aims at allowing users to
override the DSDT without recompiling the kernel.

Version 0.9 uses a different approach for reading the initramfs which avoids
using the filesystem infrastructure. It leverages the initramfs unpack code to find
and unpack the DSDT directly into the memory.

v0.9a: Fix compilation on non-ACPI platforms by René Rebe <rene@exactcode.de>
v0.9b: Declare more functions __init by Jan Beulich <jbeulich@novell.com>
v0.9c: Allow root to be / instead of nothing, bug reported by Robert Hampovcan

Signed-off-by: Eric Piel <eric.piel@tremplin-utc.net>
---
 Documentation/acpi/dsdt-override.txt     |   12 +++-
 Documentation/acpi/initramfs-add-dsdt.sh |   43 ++++++++++++++
 Documentation/kernel-parameters.txt      |    3 +
 drivers/acpi/Kconfig                     |   11 ++++
 drivers/acpi/osl.c                       |   24 ++++++++
 init/initramfs.c                         |   89 ++++++++++++++++++++++++++++++
 6 files changed, 180 insertions(+), 2 deletions(-)
 create mode 100644 Documentation/acpi/initramfs-add-dsdt.sh

diff --git a/Documentation/acpi/dsdt-override.txt b/Documentation/acpi/dsdt-override.txt
index febbb1b..5008f25 100644
--- a/Documentation/acpi/dsdt-override.txt
+++ b/Documentation/acpi/dsdt-override.txt
@@ -1,7 +1,15 @@
-Linux supports a method of overriding the BIOS DSDT:
+Linux supports two methods of overriding the BIOS DSDT:
 
 CONFIG_ACPI_CUSTOM_DSDT builds the image into the kernel.
 
-When to use this method is described in detail on the
+CONFIG_ACPI_CUSTOM_DSDT_INITRD adds the image to the initrd.
+
+When to use these methods is described in detail on the
 Linux/ACPI home page:
 http://www.lesswatts.org/projects/acpi/overridingDSDT.php
+
+Note that if both options are used, the DSDT supplied
+by the INITRD method takes precedence.
+
+Documentation/initramfs-add-dsdt.sh is provided for convenience
+for use with the CONFIG_ACPI_CUSTOM_DSDT_INITRD method.
diff --git a/Documentation/acpi/initramfs-add-dsdt.sh b/Documentation/acpi/initramfs-add-dsdt.sh
new file mode 100644
index 0000000..17ef6e8
--- /dev/null
+++ b/Documentation/acpi/initramfs-add-dsdt.sh
@@ -0,0 +1,43 @@
+#!/bin/bash
+# Adds a DSDT file to the initrd (if it's an initramfs)
+# first argument is the name of archive
+# second argument is the name of the file to add
+# The file will be copied as /DSDT.aml
+
+# 20060126: fix "Premature end of file" with some old cpio (Roland Robic)
+# 20060205: this time it should really work
+
+# check the arguments
+if [ $# -ne 2 ]; then
+	program_name=$(basename $0)
+	echo "\
+$program_name: too few arguments
+Usage: $program_name initrd-name.img DSDT-to-add.aml
+Adds a DSDT file to an initrd (in initramfs format)
+
+  initrd-name.img: filename of the initrd in initramfs format
+  DSDT-to-add.aml: filename of the DSDT file to add
+  " 1>&2
+    exit 1
+fi
+
+# we should check it's an initramfs
+
+tempcpio=$(mktemp -d)
+# cleanup on exit, hangup, interrupt, quit, termination
+trap 'rm -rf $tempcpio' 0 1 2 3 15
+
+# extract the archive
+gunzip -c "$1" > "$tempcpio"/initramfs.cpio || exit 1
+
+# copy the DSDT file at the root of the directory so that we can call it "/DSDT.aml"
+cp -f "$2" "$tempcpio"/DSDT.aml
+
+# add the file
+cd "$tempcpio"
+(echo DSDT.aml | cpio --quiet -H newc -o -A -O "$tempcpio"/initramfs.cpio) || exit 1
+cd "$OLDPWD"
+
+# re-compress the archive
+gzip -c "$tempcpio"/initramfs.cpio > "$1"
+
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 343e0f0..76707c4 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -180,6 +180,9 @@ and is between 256 and 4096 characters. It is defined in the file
 
 	acpi_no_auto_ssdt	[HW,ACPI] Disable automatic loading of SSDT
 
+	acpi_no_initrd_override	[KNL,ACPI]
+			Disable loading custom ACPI tables from the initramfs
+
 	acpi_os_name=	[HW,ACPI] Tell ACPI BIOS the name of the OS
 			Format: To spoof as Windows 98: ="Microsoft Windows"
 
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index f4f6329..f070331 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -297,6 +297,17 @@ config ACPI_CUSTOM_DSDT
 	bool
 	default ACPI_CUSTOM_DSDT_FILE != ""
 
+config ACPI_CUSTOM_DSDT_INITRD
+	bool "Read Custom DSDT from initramfs"
+	depends on BLK_DEV_INITRD
+	default n
+	help
+	  This option supports a custom DSDT by optionally loading it from initrd.
+	  See Documentation/acpi/dsdt-override.txt
+
+	  If you are not using this feature now, but may use it later,
+	  it is safe to say Y here.
+
 config ACPI_BLACKLIST_YEAR
 	int "Disable ACPI for systems before Jan 1st this year" if X86_32
 	default 0
diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 4be2521..2e0df9f 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -96,6 +96,11 @@ static DEFINE_SPINLOCK(acpi_res_lock);
 #define	OSI_STRING_LENGTH_MAX 64	/* arbitrary */
 static char osi_additional_string[OSI_STRING_LENGTH_MAX];
 
+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
+static __initdata int acpi_no_initrd_override;
+extern struct acpi_table_header *acpi_find_dsdt_initrd(void);
+#endif
+
 /*
  * "Ode to _OSI(Linux)"
  *
@@ -338,6 +343,16 @@ acpi_os_table_override(struct acpi_table_header * existing_table,
 	if (strncmp(existing_table->signature, "DSDT", 4) == 0)
 		*new_table = (struct acpi_table_header *)AmlCode;
 #endif
+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
+	if ((strncmp(existing_table->signature, "DSDT", 4) == 0) &&
+	    !acpi_no_initrd_override) {
+		struct acpi_table_header *initrd_table;
+
+		initrd_table = acpi_find_dsdt_initrd();
+		if (initrd_table)
+			*new_table = initrd_table;
+	}
+#endif
 	if (*new_table != NULL) {
 		printk(KERN_WARNING PREFIX "Override [%4.4s-%8.8s], "
 			   "this is unsafe: tainting kernel\n",
@@ -348,6 +363,15 @@ acpi_os_table_override(struct acpi_table_header * existing_table,
 	return AE_OK;
 }
 
+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
+static int __init acpi_no_initrd_override_setup(char *s)
+{
+	acpi_no_initrd_override = 1;
+	return 1;
+}
+__setup("acpi_no_initrd_override", acpi_no_initrd_override_setup);
+#endif
+
 static irqreturn_t acpi_irq(int irq, void *dev_id)
 {
 	u32 handled;
diff --git a/init/initramfs.c b/init/initramfs.c
index 4f5ba75..d2aaa87 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -7,6 +7,9 @@
 #include <linux/string.h>
 #include <linux/syscalls.h>
 #include <linux/utime.h>
+#ifdef ACPI_CONFIG
+#include <acpi/acpi.h>
+#endif
 
 static __initdata char *message;
 static void __init error(char *x)
@@ -124,6 +127,12 @@ static __initdata unsigned long body_len, name_len;
 static __initdata uid_t uid;
 static __initdata gid_t gid;
 static __initdata unsigned rdev;
+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
+static __initdata char *file_looked_for;
+static __initdata struct acpi_table_header *file_mem;
+#else
+const char *file_looked_for = NULL;
+#endif
 
 static void __init parse_header(char *s)
 {
@@ -158,6 +167,7 @@ static __initdata enum state {
 	SkipIt,
 	GotName,
 	CopyFile,
+	CopyFileMem,
 	GotSymlink,
 	Reset
 } state, next_state;
@@ -295,6 +305,54 @@ static void __init clean_path(char *path, mode_t mode)
 
 static __initdata int wfd;
 
+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
+static __init int is_file_looked_for(char *filename)
+{
+	char *tmp_collected = collected;
+	if (file_looked_for == NULL)
+		return 0;
+	if (!S_ISREG(mode))
+		return 0;
+	/* remove the leading / */
+	while (*tmp_collected == '/')
+		tmp_collected++;
+	return (strcmp(tmp_collected, file_looked_for) == 0);
+}
+
+static int __init do_copy_mem(void)
+{
+	static void *file_current; /* current position in the memory */
+	if (file_mem == NULL) {
+		if (body_len < 4) { /* check especially against empty files */
+			error("file is less than 4 bytes");
+			return 1;
+		}
+		file_mem = kmalloc(body_len, GFP_ATOMIC);
+		if (!file_mem) {
+			error("failed to allocate enough memory");
+			return 1;
+		}
+		file_current = file_mem;
+	}
+	if (count >= body_len) {
+		memcpy(file_current, victim, body_len);
+		eat(body_len);
+		file_looked_for = NULL; /* don't find files with same name */
+		state = SkipIt;
+		return 0;
+	} else {
+		memcpy(file_current, victim, count);
+		file_current += count;
+		body_len -= count;
+		eat(count);
+		return 1;
+	}
+}
+#else
+static inline int is_file_looked_for(char *filename) {return 0;}
+#define do_copy_mem NULL /* because it is used as a pointer */
+#endif
+
 static int __init do_name(void)
 {
 	state = SkipIt;
@@ -303,6 +361,8 @@ static int __init do_name(void)
 		free_hash();
 		return 0;
 	}
+	if (is_file_looked_for(file_looked_for))
+		state = CopyFileMem;
 	if (dry_run)
 		return 0;
 	clean_path(collected, mode);
@@ -375,6 +435,7 @@ static __initdata int (*actions[])(void) = {
 	[SkipIt]	= do_skip,
 	[GotName]	= do_name,
 	[CopyFile]	= do_copy,
+	[CopyFileMem]	= do_copy_mem,
 	[GotSymlink]	= do_symlink,
 	[Reset]		= do_reset,
 };
@@ -613,3 +674,31 @@ static int __init populate_rootfs(void)
 	return 0;
 }
 rootfs_initcall(populate_rootfs);
+
+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
+struct __init acpi_table_header *acpi_find_dsdt_initrd(void)
+{
+	char *err, *ramfs_dsdt_name = "DSDT.aml";
+
+	printk(KERN_INFO "ACPI: Checking initramfs for custom DSDT\n");
+	file_mem = NULL;
+	file_looked_for = ramfs_dsdt_name;
+	err = unpack_to_rootfs((char *)initrd_start,
+			initrd_end - initrd_start, 1);
+	file_looked_for = NULL;
+
+	if (err) {
+		/*
+		 * Even if reading the DSDT file was successful,
+		 * we give up if the initramfs cannot be entirely read.
+		 */
+		kfree(file_mem);
+		printk(KERN_ERR "ACPI: Aborded because %s.\n", err);
+		return NULL;
+	}
+	if (file_mem)
+		printk(KERN_INFO "ACPI: Found DSDT in %s.\n", ramfs_dsdt_name);
+
+	return file_mem;
+}
+#endif
1	niro	1114	ACPI: initramfs DSDT override support
2
3			Permits to load of DSDT (the main ACPI table) from initramfs. In case this
4			option is selected, the initramfs is parsed at ACPI initialization (very early
5			boot time) to look for a file called "DSDT.aml". This aims at allowing users to
6			override the DSDT without recompiling the kernel.
7
8			Version 0.9 uses a different approach for reading the initramfs which avoids
9			using the filesystem infrastructure. It leverages the initramfs unpack code to find
10			and unpack the DSDT directly into the memory.
11
12			v0.9a: Fix compilation on non-ACPI platforms by René Rebe <rene@exactcode.de>
13			v0.9b: Declare more functions __init by Jan Beulich <jbeulich@novell.com>
14			v0.9c: Allow root to be / instead of nothing, bug reported by Robert Hampovcan
15
16			Signed-off-by: Eric Piel <eric.piel@tremplin-utc.net>
17			---
18			Documentation/acpi/dsdt-override.txt \| 12 +++-
19			Documentation/acpi/initramfs-add-dsdt.sh \| 43 ++++++++++++++
20			Documentation/kernel-parameters.txt \| 3 +
21			drivers/acpi/Kconfig \| 11 ++++
22			drivers/acpi/osl.c \| 24 ++++++++
23			init/initramfs.c \| 89 ++++++++++++++++++++++++++++++
24			6 files changed, 180 insertions(+), 2 deletions(-)
25			create mode 100644 Documentation/acpi/initramfs-add-dsdt.sh
26
27			diff --git a/Documentation/acpi/dsdt-override.txt b/Documentation/acpi/dsdt-override.txt
28			index febbb1b..5008f25 100644
29			--- a/Documentation/acpi/dsdt-override.txt
30			+++ b/Documentation/acpi/dsdt-override.txt
31			@@ -1,7 +1,15 @@
32			-Linux supports a method of overriding the BIOS DSDT:
33			+Linux supports two methods of overriding the BIOS DSDT:
34
35			CONFIG_ACPI_CUSTOM_DSDT builds the image into the kernel.
36
37			-When to use this method is described in detail on the
38			+CONFIG_ACPI_CUSTOM_DSDT_INITRD adds the image to the initrd.
39			+
40			+When to use these methods is described in detail on the
41			Linux/ACPI home page:
42			http://www.lesswatts.org/projects/acpi/overridingDSDT.php
43			+
44			+Note that if both options are used, the DSDT supplied
45			+by the INITRD method takes precedence.
46			+
47			+Documentation/initramfs-add-dsdt.sh is provided for convenience
48			+for use with the CONFIG_ACPI_CUSTOM_DSDT_INITRD method.
49			diff --git a/Documentation/acpi/initramfs-add-dsdt.sh b/Documentation/acpi/initramfs-add-dsdt.sh
50			new file mode 100644
51			index 0000000..17ef6e8
52			--- /dev/null
53			+++ b/Documentation/acpi/initramfs-add-dsdt.sh
54			@@ -0,0 +1,43 @@
55			+#!/bin/bash
56			+# Adds a DSDT file to the initrd (if it's an initramfs)
57			+# first argument is the name of archive
58			+# second argument is the name of the file to add
59			+# The file will be copied as /DSDT.aml
60			+
61			+# 20060126: fix "Premature end of file" with some old cpio (Roland Robic)
62			+# 20060205: this time it should really work
63			+
64			+# check the arguments
65			+if [ $# -ne 2 ]; then
66			+ program_name=$(basename $0)
67			+ echo "\
68			+$program_name: too few arguments
69			+Usage: $program_name initrd-name.img DSDT-to-add.aml
70			+Adds a DSDT file to an initrd (in initramfs format)
71			+
72			+ initrd-name.img: filename of the initrd in initramfs format
73			+ DSDT-to-add.aml: filename of the DSDT file to add
74			+ " 1>&2
75			+ exit 1
76			+fi
77			+
78			+# we should check it's an initramfs
79			+
80			+tempcpio=$(mktemp -d)
81			+# cleanup on exit, hangup, interrupt, quit, termination
82			+trap 'rm -rf $tempcpio' 0 1 2 3 15
83			+
84			+# extract the archive
85			+gunzip -c "$1" > "$tempcpio"/initramfs.cpio \|\| exit 1
86			+
87			+# copy the DSDT file at the root of the directory so that we can call it "/DSDT.aml"
88			+cp -f "$2" "$tempcpio"/DSDT.aml
89			+
90			+# add the file
91			+cd "$tempcpio"
92			+(echo DSDT.aml \| cpio --quiet -H newc -o -A -O "$tempcpio"/initramfs.cpio) \|\| exit 1
93			+cd "$OLDPWD"
94			+
95			+# re-compress the archive
96			+gzip -c "$tempcpio"/initramfs.cpio > "$1"
97			+
98			diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
99			index 343e0f0..76707c4 100644
100			--- a/Documentation/kernel-parameters.txt
101			+++ b/Documentation/kernel-parameters.txt
102			@@ -180,6 +180,9 @@ and is between 256 and 4096 characters. It is defined in the file
103
104			acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
105
106			+ acpi_no_initrd_override [KNL,ACPI]
107			+ Disable loading custom ACPI tables from the initramfs
108			+
109			acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
110			Format: To spoof as Windows 98: ="Microsoft Windows"
111
112			diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
113			index f4f6329..f070331 100644
114			--- a/drivers/acpi/Kconfig
115			+++ b/drivers/acpi/Kconfig
116			@@ -297,6 +297,17 @@ config ACPI_CUSTOM_DSDT
117			bool
118			default ACPI_CUSTOM_DSDT_FILE != ""
119
120			+config ACPI_CUSTOM_DSDT_INITRD
121			+ bool "Read Custom DSDT from initramfs"
122			+ depends on BLK_DEV_INITRD
123			+ default n
124			+ help
125			+ This option supports a custom DSDT by optionally loading it from initrd.
126			+ See Documentation/acpi/dsdt-override.txt
127			+
128			+ If you are not using this feature now, but may use it later,
129			+ it is safe to say Y here.
130			+
131			config ACPI_BLACKLIST_YEAR
132			int "Disable ACPI for systems before Jan 1st this year" if X86_32
133			default 0
134			diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
135			index 4be2521..2e0df9f 100644
136			--- a/drivers/acpi/osl.c
137			+++ b/drivers/acpi/osl.c
138			@@ -96,6 +96,11 @@ static DEFINE_SPINLOCK(acpi_res_lock);
139			#define OSI_STRING_LENGTH_MAX 64 /* arbitrary */
140			static char osi_additional_string[OSI_STRING_LENGTH_MAX];
141
142			+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
143			+static __initdata int acpi_no_initrd_override;
144			+extern struct acpi_table_header *acpi_find_dsdt_initrd(void);
145			+#endif
146			+
147			/*
148			* "Ode to _OSI(Linux)"
149			*
150			@@ -338,6 +343,16 @@ acpi_os_table_override(struct acpi_table_header * existing_table,
151			if (strncmp(existing_table->signature, "DSDT", 4) == 0)
152			new_table = (struct acpi_table_header )AmlCode;
153			#endif
154			+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
155			+ if ((strncmp(existing_table->signature, "DSDT", 4) == 0) &&
156			+ !acpi_no_initrd_override) {
157			+ struct acpi_table_header *initrd_table;
158			+
159			+ initrd_table = acpi_find_dsdt_initrd();
160			+ if (initrd_table)
161			+ *new_table = initrd_table;
162			+ }
163			+#endif
164			if (*new_table != NULL) {
165			printk(KERN_WARNING PREFIX "Override [%4.4s-%8.8s], "
166			"this is unsafe: tainting kernel\n",
167			@@ -348,6 +363,15 @@ acpi_os_table_override(struct acpi_table_header * existing_table,
168			return AE_OK;
169			}
170
171			+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
172			+static int __init acpi_no_initrd_override_setup(char *s)
173			+{
174			+ acpi_no_initrd_override = 1;
175			+ return 1;
176			+}
177			+__setup("acpi_no_initrd_override", acpi_no_initrd_override_setup);
178			+#endif
179			+
180			static irqreturn_t acpi_irq(int irq, void *dev_id)
181			{
182			u32 handled;
183			diff --git a/init/initramfs.c b/init/initramfs.c
184			index 4f5ba75..d2aaa87 100644
185			--- a/init/initramfs.c
186			+++ b/init/initramfs.c
187			@@ -7,6 +7,9 @@
188			#include <linux/string.h>
189			#include <linux/syscalls.h>
190			#include <linux/utime.h>
191			+#ifdef ACPI_CONFIG
192			+#include <acpi/acpi.h>
193			+#endif
194
195			static __initdata char *message;
196			static void __init error(char *x)
197			@@ -124,6 +127,12 @@ static __initdata unsigned long body_len, name_len;
198			static __initdata uid_t uid;
199			static __initdata gid_t gid;
200			static __initdata unsigned rdev;
201			+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
202			+static __initdata char *file_looked_for;
203			+static __initdata struct acpi_table_header *file_mem;
204			+#else
205			+const char *file_looked_for = NULL;
206			+#endif
207
208			static void __init parse_header(char *s)
209			{
210			@@ -158,6 +167,7 @@ static __initdata enum state {
211			SkipIt,
212			GotName,
213			CopyFile,
214			+ CopyFileMem,
215			GotSymlink,
216			Reset
217			} state, next_state;
218			@@ -295,6 +305,54 @@ static void __init clean_path(char *path, mode_t mode)
219
220			static __initdata int wfd;
221
222			+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
223			+static __init int is_file_looked_for(char *filename)
224			+{
225			+ char *tmp_collected = collected;
226			+ if (file_looked_for == NULL)
227			+ return 0;
228			+ if (!S_ISREG(mode))
229			+ return 0;
230			+ /* remove the leading / */
231			+ while (*tmp_collected == '/')
232			+ tmp_collected++;
233			+ return (strcmp(tmp_collected, file_looked_for) == 0);
234			+}
235			+
236			+static int __init do_copy_mem(void)
237			+{
238			+ static void file_current; / current position in the memory */
239			+ if (file_mem == NULL) {
240			+ if (body_len < 4) { /* check especially against empty files */
241			+ error("file is less than 4 bytes");
242			+ return 1;
243			+ }
244			+ file_mem = kmalloc(body_len, GFP_ATOMIC);
245			+ if (!file_mem) {
246			+ error("failed to allocate enough memory");
247			+ return 1;
248			+ }
249			+ file_current = file_mem;
250			+ }
251			+ if (count >= body_len) {
252			+ memcpy(file_current, victim, body_len);
253			+ eat(body_len);
254			+ file_looked_for = NULL; /* don't find files with same name */
255			+ state = SkipIt;
256			+ return 0;
257			+ } else {
258			+ memcpy(file_current, victim, count);
259			+ file_current += count;
260			+ body_len -= count;
261			+ eat(count);
262			+ return 1;
263			+ }
264			+}
265			+#else
266			+static inline int is_file_looked_for(char *filename) {return 0;}
267			+#define do_copy_mem NULL /* because it is used as a pointer */
268			+#endif
269			+
270			static int __init do_name(void)
271			{
272			state = SkipIt;
273			@@ -303,6 +361,8 @@ static int __init do_name(void)
274			free_hash();
275			return 0;
276			}
277			+ if (is_file_looked_for(file_looked_for))
278			+ state = CopyFileMem;
279			if (dry_run)
280			return 0;
281			clean_path(collected, mode);
282			@@ -375,6 +435,7 @@ static __initdata int (*actions[])(void) = {
283			[SkipIt] = do_skip,
284			[GotName] = do_name,
285			[CopyFile] = do_copy,
286			+ [CopyFileMem] = do_copy_mem,
287			[GotSymlink] = do_symlink,
288			[Reset] = do_reset,
289			};
290			@@ -613,3 +674,31 @@ static int __init populate_rootfs(void)
291			return 0;
292			}
293			rootfs_initcall(populate_rootfs);
294			+
295			+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
296			+struct __init acpi_table_header *acpi_find_dsdt_initrd(void)
297			+{
298			+ char err, ramfs_dsdt_name = "DSDT.aml";
299			+
300			+ printk(KERN_INFO "ACPI: Checking initramfs for custom DSDT\n");
301			+ file_mem = NULL;
302			+ file_looked_for = ramfs_dsdt_name;
303			+ err = unpack_to_rootfs((char *)initrd_start,
304			+ initrd_end - initrd_start, 1);
305			+ file_looked_for = NULL;
306			+
307			+ if (err) {
308			+ /*
309			+ * Even if reading the DSDT file was successful,
310			+ * we give up if the initramfs cannot be entirely read.
311			+ */
312			+ kfree(file_mem);
313			+ printk(KERN_ERR "ACPI: Aborded because %s.\n", err);
314			+ return NULL;
315			+ }
316			+ if (file_mem)
317			+ printk(KERN_INFO "ACPI: Found DSDT in %s.\n", ramfs_dsdt_name);
318			+
319			+ return file_mem;
320			+}
321			+#endif