* [PATCH 1/2] lib: Add early cpio decoder
2012-08-30 9:29 Early cpio decoder and ACPI table override via initrd making use of it Thomas Renninger
@ 2012-08-30 9:29 ` Thomas Renninger
2012-09-04 17:00 ` H. Peter Anvin
2012-08-30 9:29 ` [PATCH 2/2] ACPI: Override arbitrary ACPI tables via initrd for debugging Thomas Renninger
1 sibling, 1 reply; 8+ messages in thread
From: Thomas Renninger @ 2012-08-30 9:29 UTC (permalink / raw)
To: hpa
Cc: linux-kernel, lenb, robert.moore, ming.m.lin, initramfs, bigeasy,
vojcek, eric.piel, linux-acpi, yinghai, H. Peter Anvin,
Thomas Renninger
From: "H. Peter Anvin" <hpa@linux.intel.com>
Add a simple cpio decoder without library dependencies for the purpose
of extracting components from the initramfs blob for early kernel
uses. Intended consumers so far are microcode and ACPI override.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
CC: Thomas Renninger <trenn@suse.de>
Link: http://lkml.kernel.org/r/201203261651.29640.trenn@suse.de
Signed-off-by: Thomas Renninger <trenn@suse.de>
---
include/linux/earlycpio.h | 13 ++++
lib/Makefile | 2 +-
lib/earlycpio.c | 173 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 187 insertions(+), 1 deletions(-)
create mode 100644 include/linux/earlycpio.h
create mode 100644 lib/earlycpio.c
diff --git a/include/linux/earlycpio.h b/include/linux/earlycpio.h
new file mode 100644
index 0000000..06db026
--- /dev/null
+++ b/include/linux/earlycpio.h
@@ -0,0 +1,13 @@
+#ifndef _LINUX_EARLYCPIO_H
+#define _LINUX_EARLYCPIO_H
+
+#include <linux/types.h>
+
+struct cpio_data {
+ void *data;
+ size_t size;
+};
+
+struct cpio_data find_cpio_data(const char *name, const void *data, size_t len);
+
+#endif /* _LINUX_EARLYCPIO_H */
diff --git a/lib/Makefile b/lib/Makefile
index 42d283e..0924041 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -12,7 +12,7 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \
idr.o int_sqrt.o extable.o prio_tree.o \
sha1.o md5.o irq_regs.o reciprocal_div.o argv_split.o \
proportions.o flex_proportions.o prio_heap.o ratelimit.o show_mem.o \
- is_single_threaded.o plist.o decompress.o
+ is_single_threaded.o plist.o decompress.o earlycpio.o
lib-$(CONFIG_MMU) += ioremap.o
lib-$(CONFIG_SMP) += cpumask.o
diff --git a/lib/earlycpio.c b/lib/earlycpio.c
new file mode 100644
index 0000000..b16b80b
--- /dev/null
+++ b/lib/earlycpio.c
@@ -0,0 +1,173 @@
+/* ----------------------------------------------------------------------- *
+ *
+ * Copyright 2012 Intel Corporation; author H. Peter Anvin
+ *
+ * This file is part of the Linux kernel, and is made available
+ * under the terms of the GNU General Public License version 2, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * earlycpio.c
+ *
+ * Find a specific cpio member; must precede any compressed content.
+ * This is used to locate data items in the initramfs used by the
+ * kernel itself during early boot (before the main initramfs is
+ * decompressed.) It is the responsibility of the initramfs creator
+ * to ensure that these items are uncompressed at the head of the
+ * blob. Depending on the boot loader or package tool that may be a
+ * separate file or part of the same file.
+ *
+ * For some architectures, e.g. i386, this file must compile to have
+ * no relocations and no library dependencies, so it can be called from
+ * a nonstandard environment. Therefore some normal library functions
+ * are inlined in this file.
+ */
+
+#include <linux/earlycpio.h>
+#include <linux/kernel.h>
+
+enum cpio_fields {
+ C_MAGIC,
+ C_INO,
+ C_MODE,
+ C_UID,
+ C_GID,
+ C_NLINK,
+ C_MTIME,
+ C_FILESIZE,
+ C_MAJ,
+ C_MIN,
+ C_RMAJ,
+ C_RMIN,
+ C_NAMESIZE,
+ C_CHKSUM,
+ C_NFIELDS
+};
+
+#ifdef CONFIG_X86
+static inline size_t strlen(const char *name)
+{
+ size_t n = -1;
+
+ asm("repne; scasb"
+ : "+D" (name), "+c" (n)
+ : "a" (0));
+
+ return -2 - n;
+}
+
+static inline int memcmp(const void *p1, const void *p2, size_t n)
+{
+ unsigned char rv;
+
+ asm("repe; cmpsb; setne %0"
+ : "=r" (rv), "+S" (p1), "+D" (p2), "+c" (n));
+
+ return rv;
+}
+#else
+static inline size_t strlen(const char *name)
+{
+ size_t n = 0;
+
+ while (*name++)
+ n++;
+
+ return n;
+}
+
+static inline int memcmp(const void *p1, const void *p2, size_t n)
+{
+ const unsigned char *u1 = p1;
+ const unsigned char *u2 = p2;
+ int d;
+
+ while (n--) {
+ d = *u2++ - *u1++;
+ if (d)
+ return d;
+ }
+ return 0;
+}
+#endif
+
+struct cpio_data __cpuinit find_cpio_data(const char *name,
+ const void *data, size_t len)
+{
+ const size_t cpio_header_len = 8*C_NFIELDS - 2;
+ struct cpio_data cd = { NULL, 0 };
+ const char *p, *dptr, *nptr;
+ unsigned int ch[C_NFIELDS], *chp, v;
+ unsigned char c, x;
+ size_t mynamesize = strlen(name) + 1;
+ int i, j;
+
+ p = data;
+
+ while (len > cpio_header_len) {
+ if (!*p) {
+ /* All cpio headers need to be 4-byte aligned */
+ p += 4;
+ len -= 4;
+ continue;
+ }
+
+ j = 6; /* The magic field is only 6 characters */
+ chp = ch;
+ for (i = C_NFIELDS; i; i--) {
+ v = 0;
+ while (j--) {
+ v <<= 4;
+ c = *p++;
+
+ x = c - '0';
+ if (x < 10) {
+ v += x;
+ continue;
+ }
+
+ x = (c | 0x20) - 'a';
+ if (x < 6) {
+ v += x + 10;
+ continue;
+ }
+
+ goto quit; /* Invalid hexadecimal */
+ }
+ *chp++ = v;
+ j = 8; /* All other fields are 8 characters */
+ }
+
+ if ((ch[C_MAGIC] - 0x070701) > 1)
+ goto quit; /* Invalid magic */
+
+ len -= cpio_header_len;
+
+ dptr = PTR_ALIGN(p + ch[C_NAMESIZE], 4);
+ nptr = PTR_ALIGN(dptr + ch[C_FILESIZE], 4);
+
+ if (nptr > p + len || dptr < p || nptr < dptr)
+ goto quit; /* Buffer overrun */
+
+ if ((ch[C_MODE] & 0170000) == 0100000 &&
+ ch[C_NAMESIZE] == mynamesize &&
+ !memcmp(p, name, mynamesize)) {
+ cd.data = (void *)dptr;
+ cd.size = ch[C_FILESIZE];
+ return cd; /* Found it! */
+ }
+
+ len -= (nptr - p);
+ p = nptr;
+ }
+
+quit:
+ return cd;
+}
--
1.7.6.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH 2/2] ACPI: Override arbitrary ACPI tables via initrd for debugging
2012-08-30 9:29 Early cpio decoder and ACPI table override via initrd making use of it Thomas Renninger
2012-08-30 9:29 ` [PATCH 1/2] lib: Add early cpio decoder Thomas Renninger
@ 2012-08-30 9:29 ` Thomas Renninger
2012-08-30 9:34 ` Thomas Renninger
1 sibling, 1 reply; 8+ messages in thread
From: Thomas Renninger @ 2012-08-30 9:29 UTC (permalink / raw)
To: hpa
Cc: linux-kernel, lenb, robert.moore, ming.m.lin, initramfs, bigeasy,
vojcek, eric.piel, linux-acpi, yinghai, Thomas Renninger
Details can be found in:
Documentation/acpi/initrd_table_override.txt
Signed-off-by: Thomas Renninger <trenn@suse.de>
CC: eric.piel@tremplin-utc.net
CC: vojcek@tlen.pl
CC: Lin Ming <ming.m.lin@intel.com>
CC: lenb@kernel.org
CC: robert.moore@intel.com
CC: hpa@zytor.com
CC: yinghai@kernel.org
---
Documentation/acpi/initrd_table_override.txt | 122 ++++++++++++++++
arch/x86/kernel/setup.c | 4 +
drivers/acpi/Kconfig | 9 ++
drivers/acpi/osl.c | 200 ++++++++++++++++++++++++--
include/linux/acpi.h | 4 +
5 files changed, 328 insertions(+), 11 deletions(-)
create mode 100644 Documentation/acpi/initrd_table_override.txt
diff --git a/Documentation/acpi/initrd_table_override.txt b/Documentation/acpi/initrd_table_override.txt
new file mode 100644
index 0000000..22222c0
--- /dev/null
+++ b/Documentation/acpi/initrd_table_override.txt
@@ -0,0 +1,122 @@
+Overriding ACPI tables via initrd
+=================================
+
+1) Introduction (What is this about)
+2) What is this for
+3) How does it work
+4) References (Where to retrieve userspace tools)
+
+1) What is this about
+---------------------
+
+If ACPI_INITRD_TABLE_OVERRIDE compile option is true, it is possible to
+override nearly any ACPI table provided by the BIOS with an instrumented,
+modified one.
+
+For a full list of ACPI tables that can be overridden, take a look at
+the char *table_sigs[MAX_ACPI_SIGNATURE]; definition in drivers/acpi/osl.c
+All ACPI tables iasl (Intel's ACPI compiler and disassembler) knows should
+be overridable, except:
+ - ACPI_SIG_RSDP (has a signature of 6 bytes)
+ - ACPI_SIG_FACS (does not have an ordinary ACPI table header)
+Both could get implemented as well.
+
+
+2) What is this for
+-------------------
+
+Please keep in mind that this is a debug option.
+ACPI tables should not get overridden for productive use.
+If BIOS ACPI tables are overridden the kernel will get tainted with the
+TAINT_OVERRIDDEN_ACPI_TABLE flag.
+Complain to your platform/BIOS vendor if you find a bug which is that sever
+that a workaround is not accepted in the Linus kernel.
+
+Still, it can and should be enabled in any kernel, because:
+ - There is no functional change with not instrumented initrds
+ - It provides a powerful feature to easily debug and test ACPI BIOS table
+ compatibility with the Linux kernel.
+
+Until now it was only possible to override the DSDT by compiling it into
+the kernel. This is a nightmare when trying to work on ACPI related bugs
+and a lot bugs got stuck because of that.
+Even for people with enough kernel knowledge, building a kernel to try out
+things is very time consuming. Also people may have to browse and modify the
+ACPI interpreter code to find a possible BIOS bug. With this feature, people
+can correct the ACPI tables and try out quickly whether this is the root cause
+that needs to get addressed in the kernel.
+
+This could even ease up testing for BIOS providers who could flush their BIOS
+to test, but overriding table via initrd is much easier and quicker.
+For example one could prepare different initrds overriding NUMA tables with
+different affinity settings. Set up a script, let the machine reboot and
+run tests over night and one can get a picture how these settings influence
+the Linux kernel and which values are best.
+
+People can instrument the dynamic ACPI (ASL) code (for example with debug
+statements showing up in syslog when the ACPI code is processed, etc.),
+to better understand BIOS to OS interfaces, to hunt down ACPI BIOS code related
+bugs quickly or to easier develop ACPI based drivers.
+
+Intstrumenting ACPI code in SSDTs is now much easier. Before, one had to copy
+all SSDTs into the DSDT to compile it into the kernel for testing
+(because only DSDT could get overridden). That's what the acpi_no_auto_ssdt
+boot param is for: the BIOS provided SSDTs are ignored and all have to get
+copied into the DSDT, complicated and time consuming.
+
+Much more use cases, depending on which ACPI parts you are working on...
+
+
+3) How does it work
+-------------------
+
+# Extract the machine's ACPI tables:
+cd /tmp
+acpidump >acpidump
+acpixtract -a acpidump
+# Disassemble, modify and recompile them:
+iasl -d *.dat
+# For example add this statement into a _PRT (PCI Routing Table) function
+# of the DSDT:
+Store("HELLO WORLD", debug)
+iasl -sa DSDT.dsl
+# Add the raw ACPI tables to an uncompressed cpio archive.
+# They must be put into /kernel/firmware/acpi/table[0-9].dat files inside the
+# cpio archive. Starting with table0.dat
+# The one uncompressed cpio archive and it must be the first.
+# Other, typically compressed cpio archives, must be
+# concatenated on top of the uncompressed one.
+mkdir -p kernel/firmware/acpi
+cp DSDT.aml kernel/firmware/acpi/table0.dat
+# Add other ACPI tables, the filename's number must increase in order
+# A maximum of ten tables (table9.dat) are allowed:
+iasl -sa FACP.dsl
+iasl -sa SSDT1.dsl
+cp FACP.aml kernel/firmware/acpi/table1.dat
+cp SSDT1.aml kernel/firmware/acpi/table2.dat
+# Create the uncompressed cpio archive and concatenate the orginal initrd
+# on top:
+find kernel | cpio -H newc --create > /boot/instrumented_initrd
+cat /boot/initrd >>/boot/instrumented_initrd
+# reboot with increased acpi debug level, e.g. boot params:
+acpi.debug_level=0x2 acpi.debug_layer=0xFFFFFFFF
+# and check your syslog:
+[ 1.268089] ACPI: PCI Interrupt Routing Table [\_SB_.PCI0._PRT]
+[ 1.272091] [ACPI Debug] String [0x0B] "HELLO WORLD"
+
+iasl is able to disassemble and recompile quite a lot different,
+also static ACPI tables.
+
+4) Where to retrieve userspace tools
+------------------------------------
+
+iasl and acpixtract are part of Intel's ACPICA project:
+http://acpica.org/
+and should be packaged by distributions (for example in the acpica package
+on SUSE).
+
+acpidump can be found in Len Browns pmtools:
+ftp://kernel.org/pub/linux/kernel/people/lenb/acpi/utils/pmtools/acpidump
+This tool is also part of the acpica package on SUSE.
+Alternatively, used ACPI tables can be retrieved via sysfs in latest kernels:
+/sys/firmware/acpi/tables
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index f4b9b80..6a91058 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -941,6 +941,10 @@ void __init setup_arch(char **cmdline_p)
reserve_initrd();
+#ifdef CONFIG_ACPI_INITRD_TABLE_OVERRIDE
+ acpi_initrd_override((void *)initrd_start, initrd_end - initrd_start);
+#endif
+
reserve_crashkernel();
vsmp_init();
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 8099895..a508f77 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -261,6 +261,15 @@ config ACPI_CUSTOM_DSDT
bool
default ACPI_CUSTOM_DSDT_FILE != ""
+config ACPI_INITRD_TABLE_OVERRIDE
+ bool
+ default y
+ help
+ This option provides functionality to override arbitrary ACPI tables
+ via initrd. No functional change if no ACPI tables are passed via
+ initrd, therefore it's safe to say Y.
+ See Documentation/acpi/initrd_table_override.txt for details
+
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 9eaf708..c549c7d 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -534,6 +534,134 @@ acpi_os_predefined_override(const struct acpi_predefined_names *init_val,
return AE_OK;
}
+#ifdef CONFIG_ACPI_INITRD_TABLE_OVERRIDE
+#include <linux/earlycpio.h>
+#include <linux/memblock.h>
+
+#include <asm/e820.h>
+
+static u64 acpi_tables_addr;
+static int all_tables_size;
+
+/* Copied from acpica/tbutils.c:acpi_tb_checksum() */
+u8 __init acpi_table_checksum(u8 *buffer, u32 length)
+{
+ u8 sum = 0;
+ u8 *end = buffer + length;
+
+ while (buffer < end)
+ sum = (u8) (sum + *(buffer++));
+ return sum;
+}
+
+/* All but ACPI_SIG_RSDP and ACPI_SIG_FACS: */
+static const char * const table_sigs[] = {
+ ACPI_SIG_BERT, ACPI_SIG_CPEP, ACPI_SIG_ECDT, ACPI_SIG_EINJ,
+ ACPI_SIG_ERST, ACPI_SIG_HEST, ACPI_SIG_MADT, ACPI_SIG_MSCT,
+ ACPI_SIG_SBST, ACPI_SIG_SLIT, ACPI_SIG_SRAT, ACPI_SIG_ASF,
+ ACPI_SIG_BOOT, ACPI_SIG_DBGP, ACPI_SIG_DMAR, ACPI_SIG_HPET,
+ ACPI_SIG_IBFT, ACPI_SIG_IVRS, ACPI_SIG_MCFG, ACPI_SIG_MCHI,
+ ACPI_SIG_SLIC, ACPI_SIG_SPCR, ACPI_SIG_SPMI, ACPI_SIG_TCPA,
+ ACPI_SIG_UEFI, ACPI_SIG_WAET, ACPI_SIG_WDAT, ACPI_SIG_WDDT,
+ ACPI_SIG_WDRT, ACPI_SIG_DSDT, ACPI_SIG_FADT, ACPI_SIG_PSDT,
+ ACPI_SIG_RSDT, ACPI_SIG_XSDT, ACPI_SIG_SSDT, NULL };
+
+/* Non-fatal errors: Affected tables/files are ignored */
+#define INVALID_TABLE(x, name) \
+ { pr_err("ACPI OVERRIDE: " x " [%s]\n", name); continue; }
+
+#define ACPI_HEADER_SIZE sizeof(struct acpi_table_header)
+
+/* Must not increase 10 or needs code modifcation below */
+#define ACPI_OVERRIDE_TABLES 10
+
+void __init acpi_initrd_override(void *data, size_t size)
+{
+ int sig, no, table_nr = 0, offset = 0;
+ struct acpi_table_header *table;
+ char cpio_path[32] = "kernel/firmware/acpi/tableX.dat";
+ struct cpio_data file;
+ struct cpio_data early_initrd_files[ACPI_OVERRIDE_TABLES];
+ char *p;
+
+ if (data == NULL)
+ return;
+
+ for (no = 0; no < ACPI_OVERRIDE_TABLES; no++) {
+ cpio_path[26] = '0' + no;
+ printk(KERN_DEBUG "ACPI override: Trying to find %s\n",
+ cpio_path);
+ file = find_cpio_data(cpio_path, data, size);
+ if (!file.data)
+ break;
+
+ if (file.size < sizeof(struct acpi_table_header))
+ INVALID_TABLE("Table smaller than ACPI header",
+ cpio_path);
+
+ table = file.data;
+
+ for (sig = 0; table_sigs[sig]; sig++)
+ if (!memcmp(table->signature, table_sigs[sig], 4))
+ break;
+
+ if (!table_sigs[sig])
+ INVALID_TABLE("Unknown signature", cpio_path);
+ if (file.size != table->length)
+ INVALID_TABLE("File length does not match table length",
+ cpio_path);
+ if (acpi_table_checksum(file.data, table->length))
+ INVALID_TABLE("Bad table checksum", cpio_path);
+
+ pr_info("%4.4s ACPI table found in initrd [%s][0x%x]\n",
+ table->signature, cpio_path, table->length);
+
+ all_tables_size += table->length;
+ early_initrd_files[table_nr].data = file.data;
+ early_initrd_files[table_nr].size = file.size;
+ table_nr++;
+ }
+ if (table_nr == 0)
+ return;
+
+ acpi_tables_addr =
+ memblock_find_in_range(0, max_low_pfn_mapped << PAGE_SHIFT,
+ all_tables_size, PAGE_SIZE);
+ if (!acpi_tables_addr) {
+ WARN_ON(1);
+ return;
+ }
+ /*
+ * Only calling e820_add_reserve does not work and the
+ * tables are invalid (memory got used) later.
+ * memblock_x86_reserve_range works as expected and the tables
+ * won't get modified. But it's not enough because ioremap will
+ * complain later (used by acpi_os_map_memory) that the pages
+ * that should get mapped are not marked "reserved".
+ * Both memblock_x86_reserve_range and e820_add_region works fine.
+ */
+ memblock_reserve(acpi_tables_addr, acpi_tables_addr + all_tables_size);
+ e820_add_region(acpi_tables_addr, all_tables_size, E820_ACPI);
+ update_e820();
+ p = early_ioremap(acpi_tables_addr, all_tables_size);
+
+ for (no = 0; no < table_nr; no++) {
+ memcpy(p + offset, early_initrd_files[no].data,
+ early_initrd_files[no].size);
+ offset += early_initrd_files[no].size;
+ }
+ early_iounmap(p, all_tables_size);
+}
+#endif /* CONFIG_ACPI_INITRD_TABLE_OVERRIDE */
+
+static void acpi_table_taint(struct acpi_table_header *table)
+{
+ pr_warn(PREFIX
+ "Override [%4.4s-%8.8s], this is unsafe: tainting kernel\n",
+ table->signature, table->oem_table_id);
+ add_taint(TAINT_OVERRIDDEN_ACPI_TABLE);
+}
+
acpi_status
acpi_os_table_override(struct acpi_table_header * existing_table,
struct acpi_table_header ** new_table)
@@ -547,24 +675,74 @@ 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
- if (*new_table != NULL) {
- printk(KERN_WARNING PREFIX "Override [%4.4s-%8.8s], "
- "this is unsafe: tainting kernel\n",
- existing_table->signature,
- existing_table->oem_table_id);
- add_taint(TAINT_OVERRIDDEN_ACPI_TABLE);
- }
+ if (*new_table != NULL)
+ acpi_table_taint(existing_table);
return AE_OK;
}
acpi_status
acpi_os_physical_table_override(struct acpi_table_header *existing_table,
- acpi_physical_address * new_address,
- u32 *new_table_length)
+ acpi_physical_address *address,
+ u32 *table_length)
{
- return AE_SUPPORT;
-}
+#ifndef CONFIG_ACPI_INITRD_TABLE_OVERRIDE
+ *table_length = 0;
+ *address = 0;
+ return AE_OK;
+#else
+ int table_offset = 0;
+ struct acpi_table_header *table;
+
+ *table_length = 0;
+ *address = 0;
+
+ if (!acpi_tables_addr)
+ return AE_OK;
+
+ do {
+ if (table_offset + ACPI_HEADER_SIZE > all_tables_size) {
+ WARN_ON(1);
+ return AE_OK;
+ }
+
+ table = acpi_os_map_memory(acpi_tables_addr + table_offset,
+ ACPI_HEADER_SIZE);
+ if (table_offset + table->length > all_tables_size) {
+ acpi_os_unmap_memory(table, ACPI_HEADER_SIZE);
+ WARN_ON(1);
+ return AE_OK;
+ }
+
+ table_offset += table->length;
+
+ if (memcmp(existing_table->signature, table->signature, 4)) {
+ acpi_os_unmap_memory(table,
+ ACPI_HEADER_SIZE);
+ continue;
+ }
+
+ /* Only override tables with matching oem id */
+ if (memcmp(table->oem_table_id, existing_table->oem_table_id,
+ ACPI_OEM_TABLE_ID_SIZE)) {
+ acpi_os_unmap_memory(table,
+ ACPI_HEADER_SIZE);
+ continue;
+ }
+
+ table_offset -= table->length;
+ *table_length = table->length;
+ acpi_os_unmap_memory(table, ACPI_HEADER_SIZE);
+ *address = acpi_tables_addr + table_offset;
+ add_taint(TAINT_OVERRIDDEN_ACPI_TABLE);
+ break;
+ } while (table_offset + ACPI_HEADER_SIZE < all_tables_size);
+
+ if (*address != 0)
+ acpi_table_taint(existing_table);
+ return AE_OK;
+#endif
+}
static irqreturn_t acpi_irq(int irq, void *dev_id)
{
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 4f2a762..87e2c9e 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -76,6 +76,10 @@ typedef int (*acpi_table_handler) (struct acpi_table_header *table);
typedef int (*acpi_table_entry_handler) (struct acpi_subtable_header *header, const unsigned long end);
+#ifdef CONFIG_ACPI_INITRD_TABLE_OVERRIDE
+void __init acpi_initrd_override(void *data, size_t size);
+#endif
+
char * __acpi_map_table (unsigned long phys_addr, unsigned long size);
void __acpi_unmap_table(char *map, unsigned long size);
int early_acpi_boot_init(void);
--
1.7.6.1
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