kernel26-magellan-server/patches-2.6.27-r2/0157-2.6.27-acpi-dsdt-initrd-0.9c.patch

Date: Wed, 19 Mar 2008 23:00:04 +0100
Subject: [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 e07c432..6849df2 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -172,6 +172,9 @@ 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 c52fca8..8df213e 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -303,6 +303,17 @@ 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 235a138..c75f285 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 8eeeccb..84f9a01 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -6,6 +6,9 @@
 #include <linux/delay.h>
 #include <linux/string.h>
 #include <linux/syscalls.h>
+#ifdef ACPI_CONFIG
+#include <acpi/acpi.h>
+#endif
 
 static __initdata char *message;
 static void __init error(char *x)
@@ -90,6 +93,12 @@ 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)
 {
@@ -123,6 +132,7 @@ static __initdata enum state {
 	SkipIt,
 	GotName,
 	CopyFile,
+	CopyFileMem,
 	GotSymlink,
 	Reset
 } state, next_state;
@@ -259,6 +269,54 @@ 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;
@@ -267,6 +325,8 @@ 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);
@@ -333,6 +393,7 @@ static __initdata int (*actions[])(void) = {
 	[SkipIt]	= do_skip,
 	[GotName]	= do_name,
 	[CopyFile]	= do_copy,
+	[CopyFileMem]	= do_copy_mem,
 	[GotSymlink]	= do_symlink,
 	[Reset]		= do_reset,
 };
@@ -578,3 +639,31 @@ 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
-- 
1.5.6.4

1	niro	728	Date: Wed, 19 Mar 2008 23:00:04 +0100
2			Subject: [PATCH] ACPI: initramfs DSDT override support
3
4			Permits to load of DSDT (the main ACPI table) from initramfs. In case this
5			option is selected, the initramfs is parsed at ACPI initialization (very early
6			boot time) to look for a file called "DSDT.aml". This aims at allowing users to
7			override the DSDT without recompiling the kernel.
8
9			Version 0.9 uses a different approach for reading the initramfs which avoids
10			using the filesystem infrastructure. It leverages the initramfs unpack code to find
11			and unpack the DSDT directly into the memory.
12
13			v0.9a: Fix compilation on non-ACPI platforms by René Rebe <rene@exactcode.de>
14			v0.9b: Declare more functions __init by Jan Beulich <jbeulich@novell.com>
15			v0.9c: Allow root to be / instead of nothing, bug reported by Robert Hampovcan
16
17			Signed-off-by: Eric Piel <eric.piel@tremplin-utc.net>
18			---
19			Documentation/acpi/dsdt-override.txt \| 12 +++-
20			Documentation/acpi/initramfs-add-dsdt.sh \| 43 ++++++++++++++
21			Documentation/kernel-parameters.txt \| 3 +
22			drivers/acpi/Kconfig \| 11 ++++
23			drivers/acpi/osl.c \| 24 ++++++++
24			init/initramfs.c \| 89 ++++++++++++++++++++++++++++++
25			6 files changed, 180 insertions(+), 2 deletions(-)
26			create mode 100644 Documentation/acpi/initramfs-add-dsdt.sh
27
28			diff --git a/Documentation/acpi/dsdt-override.txt b/Documentation/acpi/dsdt-override.txt
29			index febbb1b..5008f25 100644
30			--- a/Documentation/acpi/dsdt-override.txt
31			+++ b/Documentation/acpi/dsdt-override.txt
32			@@ -1,7 +1,15 @@
33			-Linux supports a method of overriding the BIOS DSDT:
34			+Linux supports two methods of overriding the BIOS DSDT:
35
36			CONFIG_ACPI_CUSTOM_DSDT builds the image into the kernel.
37
38			-When to use this method is described in detail on the
39			+CONFIG_ACPI_CUSTOM_DSDT_INITRD adds the image to the initrd.
40			+
41			+When to use these methods is described in detail on the
42			Linux/ACPI home page:
43			http://www.lesswatts.org/projects/acpi/overridingDSDT.php
44			+
45			+Note that if both options are used, the DSDT supplied
46			+by the INITRD method takes precedence.
47			+
48			+Documentation/initramfs-add-dsdt.sh is provided for convenience
49			+for use with the CONFIG_ACPI_CUSTOM_DSDT_INITRD method.
50			diff --git a/Documentation/acpi/initramfs-add-dsdt.sh b/Documentation/acpi/initramfs-add-dsdt.sh
51			new file mode 100644
52			index 0000000..17ef6e8
53			--- /dev/null
54			+++ b/Documentation/acpi/initramfs-add-dsdt.sh
55			@@ -0,0 +1,43 @@
56			+#!/bin/bash
57			+# Adds a DSDT file to the initrd (if it's an initramfs)
58			+# first argument is the name of archive
59			+# second argument is the name of the file to add
60			+# The file will be copied as /DSDT.aml
61			+
62			+# 20060126: fix "Premature end of file" with some old cpio (Roland Robic)
63			+# 20060205: this time it should really work
64			+
65			+# check the arguments
66			+if [ $# -ne 2 ]; then
67			+ program_name=$(basename $0)
68			+ echo "\
69			+$program_name: too few arguments
70			+Usage: $program_name initrd-name.img DSDT-to-add.aml
71			+Adds a DSDT file to an initrd (in initramfs format)
72			+
73			+ initrd-name.img: filename of the initrd in initramfs format
74			+ DSDT-to-add.aml: filename of the DSDT file to add
75			+ " 1>&2
76			+ exit 1
77			+fi
78			+
79			+# we should check it's an initramfs
80			+
81			+tempcpio=$(mktemp -d)
82			+# cleanup on exit, hangup, interrupt, quit, termination
83			+trap 'rm -rf $tempcpio' 0 1 2 3 15
84			+
85			+# extract the archive
86			+gunzip -c "$1" > "$tempcpio"/initramfs.cpio \|\| exit 1
87			+
88			+# copy the DSDT file at the root of the directory so that we can call it "/DSDT.aml"
89			+cp -f "$2" "$tempcpio"/DSDT.aml
90			+
91			+# add the file
92			+cd "$tempcpio"
93			+(echo DSDT.aml \| cpio --quiet -H newc -o -A -O "$tempcpio"/initramfs.cpio) \|\| exit 1
94			+cd "$OLDPWD"
95			+
96			+# re-compress the archive
97			+gzip -c "$tempcpio"/initramfs.cpio > "$1"
98			+
99			diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
100			index e07c432..6849df2 100644
101			--- a/Documentation/kernel-parameters.txt
102			+++ b/Documentation/kernel-parameters.txt
103			@@ -172,6 +172,9 @@ and is between 256 and 4096 characters. It is defined in the file
104
105			acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
106
107			+ acpi_no_initrd_override [KNL,ACPI]
108			+ Disable loading custom ACPI tables from the initramfs
109			+
110			acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
111			Format: To spoof as Windows 98: ="Microsoft Windows"
112
113			diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
114			index c52fca8..8df213e 100644
115			--- a/drivers/acpi/Kconfig
116			+++ b/drivers/acpi/Kconfig
117			@@ -303,6 +303,17 @@ config ACPI_CUSTOM_DSDT
118			bool
119			default ACPI_CUSTOM_DSDT_FILE != ""
120
121			+config ACPI_CUSTOM_DSDT_INITRD
122			+ bool "Read Custom DSDT from initramfs"
123			+ depends on BLK_DEV_INITRD
124			+ default n
125			+ help
126			+ This option supports a custom DSDT by optionally loading it from initrd.
127			+ See Documentation/acpi/dsdt-override.txt
128			+
129			+ If you are not using this feature now, but may use it later,
130			+ it is safe to say Y here.
131			+
132			config ACPI_BLACKLIST_YEAR
133			int "Disable ACPI for systems before Jan 1st this year" if X86_32
134			default 0
135			diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
136			index 235a138..c75f285 100644
137			--- a/drivers/acpi/osl.c
138			+++ b/drivers/acpi/osl.c
139			@@ -96,6 +96,11 @@ static DEFINE_SPINLOCK(acpi_res_lock);
140			#define OSI_STRING_LENGTH_MAX 64 /* arbitrary */
141			static char osi_additional_string[OSI_STRING_LENGTH_MAX];
142
143			+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
144			+static __initdata int acpi_no_initrd_override;
145			+extern struct acpi_table_header *acpi_find_dsdt_initrd(void);
146			+#endif
147			+
148			/*
149			* "Ode to _OSI(Linux)"
150			*
151			@@ -338,6 +343,16 @@ acpi_os_table_override(struct acpi_table_header * existing_table,
152			if (strncmp(existing_table->signature, "DSDT", 4) == 0)
153			new_table = (struct acpi_table_header )AmlCode;
154			#endif
155			+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
156			+ if ((strncmp(existing_table->signature, "DSDT", 4) == 0) &&
157			+ !acpi_no_initrd_override) {
158			+ struct acpi_table_header *initrd_table;
159			+
160			+ initrd_table = acpi_find_dsdt_initrd();
161			+ if (initrd_table)
162			+ *new_table = initrd_table;
163			+ }
164			+#endif
165			if (*new_table != NULL) {
166			printk(KERN_WARNING PREFIX "Override [%4.4s-%8.8s], "
167			"this is unsafe: tainting kernel\n",
168			@@ -348,6 +363,15 @@ acpi_os_table_override(struct acpi_table_header * existing_table,
169			return AE_OK;
170			}
171
172			+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
173			+static int __init acpi_no_initrd_override_setup(char *s)
174			+{
175			+ acpi_no_initrd_override = 1;
176			+ return 1;
177			+}
178			+__setup("acpi_no_initrd_override", acpi_no_initrd_override_setup);
179			+#endif
180			+
181			static irqreturn_t acpi_irq(int irq, void *dev_id)
182			{
183			u32 handled;
184			diff --git a/init/initramfs.c b/init/initramfs.c
185			index 8eeeccb..84f9a01 100644
186			--- a/init/initramfs.c
187			+++ b/init/initramfs.c
188			@@ -6,6 +6,9 @@
189			#include <linux/delay.h>
190			#include <linux/string.h>
191			#include <linux/syscalls.h>
192			+#ifdef ACPI_CONFIG
193			+#include <acpi/acpi.h>
194			+#endif
195
196			static __initdata char *message;
197			static void __init error(char *x)
198			@@ -90,6 +93,12 @@ static __initdata unsigned long body_len, name_len;
199			static __initdata uid_t uid;
200			static __initdata gid_t gid;
201			static __initdata unsigned rdev;
202			+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
203			+static __initdata char *file_looked_for;
204			+static __initdata struct acpi_table_header *file_mem;
205			+#else
206			+const char *file_looked_for = NULL;
207			+#endif
208
209			static void __init parse_header(char *s)
210			{
211			@@ -123,6 +132,7 @@ static __initdata enum state {
212			SkipIt,
213			GotName,
214			CopyFile,
215			+ CopyFileMem,
216			GotSymlink,
217			Reset
218			} state, next_state;
219			@@ -259,6 +269,54 @@ static void __init clean_path(char *path, mode_t mode)
220
221			static __initdata int wfd;
222
223			+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
224			+static __init int is_file_looked_for(char *filename)
225			+{
226			+ char *tmp_collected = collected;
227			+ if (file_looked_for == NULL)
228			+ return 0;
229			+ if (!S_ISREG(mode))
230			+ return 0;
231			+ /* remove the leading / */
232			+ while (*tmp_collected == '/')
233			+ tmp_collected++;
234			+ return (strcmp(tmp_collected, file_looked_for) == 0);
235			+}
236			+
237			+static int __init do_copy_mem(void)
238			+{
239			+ static void file_current; / current position in the memory */
240			+ if (file_mem == NULL) {
241			+ if (body_len < 4) { /* check especially against empty files */
242			+ error("file is less than 4 bytes");
243			+ return 1;
244			+ }
245			+ file_mem = kmalloc(body_len, GFP_ATOMIC);
246			+ if (!file_mem) {
247			+ error("failed to allocate enough memory");
248			+ return 1;
249			+ }
250			+ file_current = file_mem;
251			+ }
252			+ if (count >= body_len) {
253			+ memcpy(file_current, victim, body_len);
254			+ eat(body_len);
255			+ file_looked_for = NULL; /* don't find files with same name */
256			+ state = SkipIt;
257			+ return 0;
258			+ } else {
259			+ memcpy(file_current, victim, count);
260			+ file_current += count;
261			+ body_len -= count;
262			+ eat(count);
263			+ return 1;
264			+ }
265			+}
266			+#else
267			+static inline int is_file_looked_for(char *filename) {return 0;}
268			+#define do_copy_mem NULL /* because it is used as a pointer */
269			+#endif
270			+
271			static int __init do_name(void)
272			{
273			state = SkipIt;
274			@@ -267,6 +325,8 @@ static int __init do_name(void)
275			free_hash();
276			return 0;
277			}
278			+ if (is_file_looked_for(file_looked_for))
279			+ state = CopyFileMem;
280			if (dry_run)
281			return 0;
282			clean_path(collected, mode);
283			@@ -333,6 +393,7 @@ static __initdata int (*actions[])(void) = {
284			[SkipIt] = do_skip,
285			[GotName] = do_name,
286			[CopyFile] = do_copy,
287			+ [CopyFileMem] = do_copy_mem,
288			[GotSymlink] = do_symlink,
289			[Reset] = do_reset,
290			};
291			@@ -578,3 +639,31 @@ static int __init populate_rootfs(void)
292			return 0;
293			}
294			rootfs_initcall(populate_rootfs);
295			+
296			+#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD
297			+struct __init acpi_table_header *acpi_find_dsdt_initrd(void)
298			+{
299			+ char err, ramfs_dsdt_name = "DSDT.aml";
300			+
301			+ printk(KERN_INFO "ACPI: Checking initramfs for custom DSDT\n");
302			+ file_mem = NULL;
303			+ file_looked_for = ramfs_dsdt_name;
304			+ err = unpack_to_rootfs((char *)initrd_start,
305			+ initrd_end - initrd_start, 1);
306			+ file_looked_for = NULL;
307			+
308			+ if (err) {
309			+ /*
310			+ * Even if reading the DSDT file was successful,
311			+ * we give up if the initramfs cannot be entirely read.
312			+ */
313			+ kfree(file_mem);
314			+ printk(KERN_ERR "ACPI: Aborded because %s.\n", err);
315			+ return NULL;
316			+ }
317			+ if (file_mem)
318			+ printk(KERN_INFO "ACPI: Found DSDT in %s.\n", ramfs_dsdt_name);
319			+
320			+ return file_mem;
321			+}
322			+#endif
323			--
324			1.5.6.4
325