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ACPI / tables: table override from built-in initrd

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In some scenario, we need to build initrd with kernel in a single image.
This can simplify system deployment process by downloading the whole system
once, such as in IC verification.

This patch adds support to override ACPI tables from built-in initrd.

Signed-off-by: Shunyong Yang <shunyong.yang@hxt-semitech.com>
[ rjw: Minor cleanups ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Shunyong Yang 2018-12-18 14:02:45 +08:00 committed by Rafael J. Wysocki
parent 1c7fc5cbc3
commit 98a455d91e
4 changed files with 27 additions and 2 deletions
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4
Documentation/acpi/initrd_table_override.txt
View File

@ -14,6 +14,10 @@ upgrade the ACPI execution environment that is defined by the ACPI tables
via upgrading the ACPI tables provided by the BIOS with an instrumented,
modified, more recent version one, or installing brand new ACPI tables.
When building initrd with kernel in a single image, option
ACPI_TABLE_OVERRIDE_VIA_BUILTIN_INITRD should also be true for this
feature to work.
For a full list of ACPI tables that can be upgraded/installed, take a look
at the char *table_sigs[MAX_ACPI_SIGNATURE]; definition in
drivers/acpi/tables.c.

10
drivers/acpi/Kconfig
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@ -357,6 +357,16 @@ config ACPI_TABLE_UPGRADE
initrd, therefore it's safe to say Y.
See Documentation/acpi/initrd_table_override.txt for details
config ACPI_TABLE_OVERRIDE_VIA_BUILTIN_INITRD
bool "Override ACPI tables from built-in initrd"
depends on ACPI_TABLE_UPGRADE
depends on INITRAMFS_SOURCE!="" && INITRAMFS_COMPRESSION=""
help
This option provides functionality to override arbitrary ACPI tables
from built-in uncompressed initrd.
See Documentation/acpi/initrd_table_override.txt for details
config ACPI_DEBUG
bool "Debug Statements"
help

12
drivers/acpi/tables.c
View File

@ -473,14 +473,22 @@ static DECLARE_BITMAP(acpi_initrd_installed, NR_ACPI_INITRD_TABLES);
void __init acpi_table_upgrade(void)
{
void *data = (void *)initrd_start;
size_t size = initrd_end - initrd_start;
void *data;
size_t size;
int sig, no, table_nr = 0, total_offset = 0;
long offset = 0;
struct acpi_table_header *table;
char cpio_path[32] = "kernel/firmware/acpi/";
struct cpio_data file;
if (IS_ENABLED(CONFIG_ACPI_TABLE_OVERRIDE_VIA_BUILTIN_INITRD)) {
data = __initramfs_start;
size = __initramfs_size;
} else {
data = (void *)initrd_start;
size = initrd_end - initrd_start;
}
if (data == NULL || size == 0)
return;

3
include/linux/initrd.h
View File

@ -25,3 +25,6 @@ extern phys_addr_t phys_initrd_start;
extern unsigned long phys_initrd_size;
extern unsigned int real_root_dev;
extern char __initramfs_start[];
extern unsigned long __initramfs_size;