x86: zImage: Propagate acpi_rsdp_addr to kernel via boot parameters
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>
diff --git a/arch/x86/lib/acpi_table.c b/arch/x86/lib/acpi_table.c
index 7b33cd3..d3e5d2e 100644
--- a/arch/x86/lib/acpi_table.c
+++ b/arch/x86/lib/acpi_table.c
@@ -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 @@
debug("current = %x\n", current);
+ acpi_rsdp_addr = (unsigned long)rsdp;
debug("ACPI: done\n");
/* Don't touch ACPI hardware on HW reduced platforms */
diff --git a/arch/x86/lib/acpi_table.h b/arch/x86/lib/acpi_table.h
new file mode 100644
index 0000000..cece5d1
--- /dev/null
+++ b/arch/x86/lib/acpi_table.h
@@ -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
diff --git a/arch/x86/lib/zimage.c b/arch/x86/lib/zimage.c
index d224db4..eae2663 100644
--- a/arch/x86/lib/zimage.c
+++ b/arch/x86/lib/zimage.c
@@ -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 @@
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;