Memory information in SRAT is necessary to fix the conflict between
KASLR and memory-hotremove.
ACPI SRAT (System/Static Resource Affinity Table) shows the details
about memory ranges, including ranges of memory provided by hot-added
memory devices. SRAT is introduced by Root System Description
Pointer(RSDP), so RSDP should be found firstly.
When booting form KEXEC/EFI/BIOS, the methods to find RSDP
are different. When booting from KEXEC, 'acpi_rsdp' may have been
added to cmdline, so parse cmdline to find RSDP.
Signed-off-by: Chao Fan <fanc.f...@cn.fujitsu.com>
---
arch/x86/boot/compressed/acpi.c | 30 ++++++++++++++++++++++++++++++
1 file changed, 30 insertions(+)
create mode 100644 arch/x86/boot/compressed/acpi.c
diff --git a/arch/x86/boot/compressed/acpi.c b/arch/x86/boot/compressed/acpi.c
new file mode 100644
index 000000000000..44f19546c169
--- /dev/null
+++ b/arch/x86/boot/compressed/acpi.c
@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: GPL-2.0
+#define BOOT_CTYPE_H
+#include "misc.h"
+#include "error.h"
+
+#include <linux/efi.h>
+#include <linux/numa.h>
+#include <linux/acpi.h>
+#include <asm/efi.h>
+
+/* Max length of 64-bit hex address string is 18, prefix "0x" + 16 hex digits
*/
+#define MAX_ADDRESS_LENGTH 18
+
+static acpi_physical_address get_acpi_rsdp(void)
+{
+#ifdef CONFIG_KEXEC
+ char val[MAX_ADDRESS_LENGTH+1];
+ unsigned long long res;
+ int len;
+
+ len = cmdline_find_option("acpi_rsdp", val, MAX_ADDRESS_LENGTH+1);
+ if (len > 0) {
+ char *e;
+
+ val[len] = '\0';
+ return (acpi_physical_address)simple_strtoull(val, &e, 16);
+ }
+#endif
+ return 0;
+}
--
2.19.2
