From 33f0df8d843deb9ec24116dcd79a40ca0ea8e8a9 Mon Sep 17 00:00:00 2001 From: Chao Fan Date: Wed, 23 Jan 2019 19:08:46 +0800 Subject: [PATCH] x86/boot: Search for RSDP in the EFI tables The immovable memory ranges information in the SRAT table is necessary to fix the issue of KASLR not paying attention to movable memory regions when selecting the offset. Therefore, SRAT needs to be parsed. Depending on the boot: KEXEC/EFI/BIOS, the methods to compute RSDP are different. When booting from EFI, the EFI table points to the RSDP. So iterate over the EFI system tables in order to find the RSDP. [ bp: - Heavily massage commit message - Trim comments - Move the CONFIG_ACPI ifdeffery into the Makefile. ] 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: kasong@redhat.com Cc: Kees Cook Cc: msys.mizuma@gmail.com Cc: Thomas Gleixner Cc: x86-ml Link: https://lkml.kernel.org/r/20190123110850.12433-4-fanc.fnst@cn.fujitsu.com --- arch/x86/boot/compressed/acpi.c | 81 ++++++++++++++++++++++++++++++++- 1 file changed, 79 insertions(+), 2 deletions(-) diff --git a/arch/x86/boot/compressed/acpi.c b/arch/x86/boot/compressed/acpi.c index bacfc4ea35ac..5559fde1c0fe 100644 --- a/arch/x86/boot/compressed/acpi.c +++ b/arch/x86/boot/compressed/acpi.c @@ -4,7 +4,8 @@ #include "error.h" #include "../string.h" -#ifdef CONFIG_ACPI +#include +#include /* * Max length of 64-bit hex address string is 19, prefix "0x" + 16 hex @@ -29,4 +30,80 @@ static acpi_physical_address get_acpi_rsdp(void) #endif return addr; } -#endif /* CONFIG_ACPI */ + +/* Search EFI system tables for RSDP. */ +static acpi_physical_address efi_get_rsdp_addr(void) +{ + acpi_physical_address rsdp_addr = 0; + +#ifdef CONFIG_EFI + efi_system_table_t *systab; + struct efi_info *ei; + bool efi_64; + int size, i; + char *sig; + + ei = &boot_params->efi_info; + sig = (char *)&ei->efi_loader_signature; + + if (!strncmp(sig, EFI64_LOADER_SIGNATURE, 4)) { + efi_64 = true; + } else if (!strncmp(sig, EFI32_LOADER_SIGNATURE, 4)) { + efi_64 = false; + } else { + debug_putstr("Wrong EFI loader signature.\n"); + return 0; + } + + /* Get systab from boot params. */ +#ifdef CONFIG_X86_64 + systab = (efi_system_table_t *)(ei->efi_systab | ((__u64)ei->efi_systab_hi<<32)); +#else + if (ei->efi_systab_hi || ei->efi_memmap_hi) { + debug_putstr("Error getting RSDP address: EFI system table located above 4GB.\n"); + return 0; + } + systab = (efi_system_table_t *)ei->efi_systab; +#endif + if (!systab) + error("EFI system table not found."); + + /* + * Get EFI tables from systab. + */ + size = efi_64 ? sizeof(efi_config_table_64_t) : + sizeof(efi_config_table_32_t); + + for (i = 0; i < systab->nr_tables; i++) { + acpi_physical_address table; + void *config_tables; + efi_guid_t guid; + + config_tables = (void *)(systab->tables + size * i); + if (efi_64) { + efi_config_table_64_t *tmp_table; + + tmp_table = config_tables; + guid = tmp_table->guid; + table = tmp_table->table; + + if (!IS_ENABLED(CONFIG_X86_64) && table >> 32) { + debug_putstr("Error getting RSDP address: EFI config table located above 4GB.\n"); + return 0; + } + } else { + efi_config_table_32_t *tmp_table; + + tmp_table = config_tables; + guid = tmp_table->guid; + table = tmp_table->table; + } + + if (!(efi_guidcmp(guid, ACPI_TABLE_GUID))) + rsdp_addr = table; + else if (!(efi_guidcmp(guid, ACPI_20_TABLE_GUID))) + return table; + } +#endif + return rsdp_addr; +}