Messages in this thread Patch in this message | | | From | Chao Fan <> | Subject | [PATCH v13 2/6] x86/boot: Introduce get_acpi_rsdp() to parse RSDP in cmdline from KEXEC | Date | Wed, 12 Dec 2018 11:10:49 +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.
Since 'RANDOMIZE_BASE' && 'MEMORY_HOTREMOVE' is needed, introduce 'CONFIG_EARLY_PARSE_RSDP' to make ifdeffery clear.
Signed-off-by: Chao Fan <fanc.fnst@cn.fujitsu.com> --- arch/x86/Kconfig | 10 ++++++++++ arch/x86/boot/compressed/acpi.c | 30 ++++++++++++++++++++++++++++++ arch/x86/boot/compressed/misc.h | 6 ++++++ 3 files changed, 46 insertions(+) create mode 100644 arch/x86/boot/compressed/acpi.c
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index ba7e3464ee92..455da382fa9e 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -2149,6 +2149,16 @@ config X86_NEED_RELOCS def_bool y depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) +config EARLY_PARSE_RSDP + bool "Parse RSDP pointer on compressed period for KASLR" + def_bool y + depends on RANDOMIZE_BASE && MEMORY_HOTREMOVE + help + This option parses RSDP in compressed period. Works + for KASLR to get memory information from SRAT table and choose + immovable memory to extract kernel. + Say Y if you want to use both KASLR and memory-hotremove. + config PHYSICAL_ALIGN hex "Alignment value to which kernel should be aligned" default "0x200000" diff --git a/arch/x86/boot/compressed/acpi.c b/arch/x86/boot/compressed/acpi.c new file mode 100644 index 000000000000..cad15686f82c --- /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> + +#define STATIC +#include <linux/decompress/mm.h> + +#include "../string.h" + +static acpi_physical_address get_acpi_rsdp(void) +{ +#ifdef CONFIG_KEXEC + unsigned long long res; + int len = 0; + char val[MAX_ADDRESS_LENGTH+1]; + + len = cmdline_find_option("acpi_rsdp", val, MAX_ADDRESS_LENGTH+1); + if (len > 0) { + val[len] = 0; + return (acpi_physical_address)kstrtoull(val, 16, &res); + } + return 0; +#endif +} diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h index a1d5918765f3..72fcfbfec3c6 100644 --- a/arch/x86/boot/compressed/misc.h +++ b/arch/x86/boot/compressed/misc.h @@ -116,3 +116,9 @@ static inline void console_init(void) void set_sev_encryption_mask(void); #endif + +/* acpi.c */ +#ifdef CONFIG_EARLY_PARSE_RSDP +/* Max length of 64-bit hex address string is 18, prefix "0x" + 16 hex digit. */ +#define MAX_ADDRESS_LENGTH 18 +#endif -- 2.19.2
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