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x86: zImage: Propagate acpi_rsdp_addr to kernel via boot parameters

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New field acpi_rsdp_addr, which has been introduced in boot protocol
v2.14 [1], in boot parameters tells kernel the exact address of RDSP
ACPI table. Knowing it increases robustness of the kernel by avoiding
in some cases traversal through a part of physical memory.
It will slightly reduce boot time by the same reason.

[1] See Linux kernel commit

  2f74cbf ("x86/boot: Add the ACPI RSDP address to struct setup_header::acpi_rdsp_addr")
  @ https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=2f74cbf

for the details.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
[bmeng: updated the kernel commit git URL and fixed one style issue]
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
This commit is contained in:
Andy Shevchenko 2018-01-10 19:40:15 +02:00 committed by Bin Meng
parent 378960d8c2
commit 3469bf4274
4 changed files with 22 additions and 0 deletions
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1
arch/x86/include/asm/bootparam.h
View File

@ -66,6 +66,7 @@ struct setup_header {
__u64 pref_address;
__u32 init_size;
__u32 handover_offset;
__u64 acpi_rsdp_addr;
} __attribute__((packed));
struct sys_desc_table {

5
arch/x86/lib/acpi_table.c
View File

@ -20,6 +20,7 @@
#include <asm/mpspec.h>
#include <asm/tables.h>
#include <asm/arch/global_nvs.h>
#include "acpi_table.h"
/*
* IASL compiles the dsdt entries and writes the hex values
@ -27,6 +28,9 @@
*/
extern const unsigned char AmlCode[];
/* ACPI RSDP address to be used in boot parameters */
unsigned long acpi_rsdp_addr;
static void acpi_write_rsdp(struct acpi_rsdp *rsdp, struct acpi_rsdt *rsdt,
struct acpi_xsdt *xsdt)
{
@ -460,6 +464,7 @@ ulong write_acpi_tables(ulong start)
debug("current = %x\n", current);
acpi_rsdp_addr = (unsigned long)rsdp;
debug("ACPI: done\n");
/* Don't touch ACPI hardware on HW reduced platforms */

10
arch/x86/lib/acpi_table.h Normal file
View File

@ -0,0 +1,10 @@
/*
* SPDX-License-Identifier: GPL-2.0
*/
#ifndef _X86_LIB_ACPI_TABLES_H
#define _X86_LIB_ACPI_TABLES_H
extern unsigned long acpi_rsdp_addr;
#endif

6
arch/x86/lib/zimage.c
View File

@ -24,6 +24,7 @@
#include <asm/arch/timestamp.h>
#endif
#include <linux/compiler.h>
#include "acpi_table.h"
DECLARE_GLOBAL_DATA_PTR;
@ -255,6 +256,11 @@ int setup_zimage(struct boot_params *setup_base, char *cmd_line, int auto_boot,
hdr->hardware_subarch = X86_SUBARCH_INTEL_MID;
#endif
#ifdef CONFIG_GENERATE_ACPI_TABLE
if (bootproto >= 0x020e)
hdr->acpi_rsdp_addr = acpi_rsdp_addr;
#endif
setup_video(&setup_base->screen_info);
return 0;