From 3c98e71b42a7d0c14639ccb565ea315f3c887f92 Mon Sep 17 00:00:00 2001 From: Chao Fan Date: Wed, 23 Jan 2019 19:08:45 +0800 Subject: [PATCH] x86/boot: Add "acpi_rsdp=" early parsing KASLR may randomly choose offsets which are located in movable memory regions resulting in the movable memory becoming immovable. The ACPI SRAT (System/Static Resource Affinity Table) describes memory ranges including ranges of memory provided by hot-added memory devices. In order to access SRAT, one needs the Root System Description Pointer (RSDP) with which to find the Root/Extended System Description Table (R/XSDT) which then contains the system description tables of which SRAT is one of. In case the RSDP address has been passed on the command line (kexec-ing a second kernel) parse it from there. [ bp: Rewrite the commit message and cleanup the code. ] Signed-off-by: Chao Fan Signed-off-by: Borislav Petkov Cc: bhe@redhat.com Cc: caoj.fnst@cn.fujitsu.com Cc: "H. Peter Anvin" Cc: indou.takao@jp.fujitsu.com Cc: Ingo Molnar Cc: Juergen Gross Cc: kasong@redhat.com Cc: Kees Cook Cc: "Kirill A. Shutemov" Cc: msys.mizuma@gmail.com Cc: Thomas Gleixner Cc: Tom Lendacky Cc: x86-ml Link: https://lkml.kernel.org/r/20190123110850.12433-3-fanc.fnst@cn.fujitsu.com --- arch/x86/boot/compressed/acpi.c | 32 ++++++++++++++++++++++++++++++++ arch/x86/boot/compressed/misc.h | 3 +++ 2 files changed, 35 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..bacfc4ea35ac --- /dev/null +++ b/arch/x86/boot/compressed/acpi.c @@ -0,0 +1,32 @@ +// SPDX-License-Identifier: GPL-2.0 +#define BOOT_CTYPE_H +#include "misc.h" +#include "error.h" +#include "../string.h" + +#ifdef CONFIG_ACPI + +/* + * Max length of 64-bit hex address string is 19, prefix "0x" + 16 hex + * digits, and '\0' for termination. + */ +#define MAX_ADDR_LEN 19 + +static acpi_physical_address get_acpi_rsdp(void) +{ + acpi_physical_address addr = 0; + +#ifdef CONFIG_KEXEC + char val[MAX_ADDR_LEN] = { }; + int ret; + + ret = cmdline_find_option("acpi_rsdp", val, MAX_ADDR_LEN); + if (ret < 0) + return 0; + + if (kstrtoull(val, 16, &addr)) + return 0; +#endif + return addr; +} +#endif /* CONFIG_ACPI */ diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h index a1d5918765f3..764ad50c0119 100644 --- a/arch/x86/boot/compressed/misc.h +++ b/arch/x86/boot/compressed/misc.h @@ -25,6 +25,9 @@ #include #include +#define BOOT_CTYPE_H +#include + #define BOOT_BOOT_H #include "../ctype.h" -- 2.11.0