From 57bd1905b228f2a14d7506b0302f69f425131e57 Mon Sep 17 00:00:00 2001 From: Tom Lendacky Date: Fri, 28 Jul 2017 11:01:17 -0500 Subject: [PATCH] acpi, x86/mm: Remove encryption mask from ACPI page protection type The arch_apei_get_mem_attributes() function is used to set the page protection type for ACPI physical addresses. When SME is active, the associated protection type cannot have the encryption mask set since the ACPI tables live in un-encrypted memory - the kernel will see corrupted data. To fix this, create a new protection type, PAGE_KERNEL_NOENC, that is a 'no encryption' version of PAGE_KERNEL, and return that from arch_apei_get_mem_attributes(). Signed-off-by: Tom Lendacky Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brijesh Singh Cc: Dave Young Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/e1cb9395b2f061cd96f1e59c3cbbe5ff5d4ec26e.1501186516.git.thomas.lendacky@amd.com Signed-off-by: Ingo Molnar --- arch/x86/include/asm/acpi.h | 11 ++++++----- arch/x86/include/asm/pgtable_types.h | 1 + 2 files changed, 7 insertions(+), 5 deletions(-) diff --git a/arch/x86/include/asm/acpi.h b/arch/x86/include/asm/acpi.h index 562286fa151f..72d867f6b518 100644 --- a/arch/x86/include/asm/acpi.h +++ b/arch/x86/include/asm/acpi.h @@ -160,12 +160,13 @@ static inline pgprot_t arch_apei_get_mem_attribute(phys_addr_t addr) * you call efi_mem_attributes() during boot and at runtime, * you could theoretically see different attributes. * - * Since we are yet to see any x86 platforms that require - * anything other than PAGE_KERNEL (some arm64 platforms - * require the equivalent of PAGE_KERNEL_NOCACHE), return that - * until we know differently. + * We are yet to see any x86 platforms that require anything + * other than PAGE_KERNEL (some ARM64 platforms require the + * equivalent of PAGE_KERNEL_NOCACHE). Additionally, if SME + * is active, the ACPI information will not be encrypted, + * so return PAGE_KERNEL_NOENC until we know differently. */ - return PAGE_KERNEL; + return PAGE_KERNEL_NOENC; } #endif diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h index 6c55973ebab8..399261ce904c 100644 --- a/arch/x86/include/asm/pgtable_types.h +++ b/arch/x86/include/asm/pgtable_types.h @@ -211,6 +211,7 @@ enum page_cache_mode { #define __PAGE_KERNEL_NOENC_WP (__PAGE_KERNEL_WP) #define PAGE_KERNEL __pgprot(__PAGE_KERNEL | _PAGE_ENC) +#define PAGE_KERNEL_NOENC __pgprot(__PAGE_KERNEL) #define PAGE_KERNEL_RO __pgprot(__PAGE_KERNEL_RO | _PAGE_ENC) #define PAGE_KERNEL_EXEC __pgprot(__PAGE_KERNEL_EXEC | _PAGE_ENC) #define PAGE_KERNEL_EXEC_NOENC __pgprot(__PAGE_KERNEL_EXEC)