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Commit 98a455d9 authored by Shunyong Yang's avatar Shunyong Yang Committed by Rafael J. Wysocki
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ACPI / tables: table override from built-in initrd 



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: default avatarShunyong Yang <shunyong.yang@hxt-semitech.com>
[ rjw: Minor cleanups ]
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 1c7fc5cb

Documentation/acpi/initrd_table_override.txt

+4 −0
Original line number Diff line number Diff line
@@ -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.

drivers/acpi/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -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

drivers/acpi/tables.c

+10 −2
Original line number Diff line number Diff line
@@ -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;

include/linux/initrd.h

+3 −0
Original line number Diff line number Diff line
@@ -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;