Messages in this thread Patch in this message | | | From | Chao Fan <> | Subject | [PATCH v14 1/5] x86/boot: Introduce get_acpi_rsdp() to parse RSDP in cmdline from KEXEC | Date | Fri, 14 Dec 2018 17:30:09 +0800 |
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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.fnst@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
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