From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752352AbdKWAgD (ORCPT ); Wed, 22 Nov 2017 19:36:03 -0500 Received: from mga09.intel.com ([134.134.136.24]:32283 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752246AbdKWAf6 (ORCPT ); Wed, 22 Nov 2017 19:35:58 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.44,438,1505804400"; d="scan'208";a="1247455155" Subject: [PATCH 07/23] x86, kaiser: make sure static PGDs are 8k in size To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, dave.hansen@linux.intel.com, moritz.lipp@iaik.tugraz.at, daniel.gruss@iaik.tugraz.at, michael.schwarz@iaik.tugraz.at, richard.fellner@student.tugraz.at, luto@kernel.org, torvalds@linux-foundation.org, keescook@google.com, hughd@google.com, x86@kernel.org From: Dave Hansen Date: Wed, 22 Nov 2017 16:34:50 -0800 References: <20171123003438.48A0EEDE@viggo.jf.intel.com> In-Reply-To: <20171123003438.48A0EEDE@viggo.jf.intel.com> Message-Id: <20171123003450.76492124@viggo.jf.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dave Hansen A few PGDs come out of the kernel binary instead of being allocated dynamically. Before this patch, they are all 8k-aligned, but they must also be 8k in *size*. The original KAISER patch did not do this. It probably just lucked out that it did not trample over data after the last PGD. Signed-off-by: Dave Hansen Cc: Moritz Lipp Cc: Daniel Gruss Cc: Michael Schwarz Cc: Richard Fellner Cc: Andy Lutomirski Cc: Linus Torvalds Cc: Kees Cook Cc: Hugh Dickins Cc: x86@kernel.org --- b/arch/x86/kernel/head_64.S | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff -puN arch/x86/kernel/head_64.S~kaiser-head_S-pgds-need-8k-too arch/x86/kernel/head_64.S --- a/arch/x86/kernel/head_64.S~kaiser-head_S-pgds-need-8k-too 2017-11-22 15:45:47.913619742 -0800 +++ b/arch/x86/kernel/head_64.S 2017-11-22 15:45:47.916619742 -0800 @@ -342,11 +342,24 @@ GLOBAL(early_recursion_flag) GLOBAL(name) #ifdef CONFIG_KAISER +/* + * Each PGD needs to be 8k long and 8k aligned. We do not + * ever go out to userspace with these, so we do not + * strictly *need* the second page, but this allows us to + * have a single set_pgd() implementation that does not + * need to worry about whether it has 4k or 8k to work + * with. + * + * This ensures PGDs are 8k long: + */ +#define KAISER_USER_PGD_FILL 512 +/* This ensures they are 8k-aligned: */ #define NEXT_PGD_PAGE(name) \ .balign 2 * PAGE_SIZE; \ GLOBAL(name) #else #define NEXT_PGD_PAGE(name) NEXT_PAGE(name) +#define KAISER_USER_PGD_FILL 0 #endif /* Automate the creation of 1 to 1 mapping pmd entries */ @@ -365,6 +378,7 @@ NEXT_PGD_PAGE(early_top_pgt) #else .quad level3_kernel_pgt - __START_KERNEL_map + _PAGE_TABLE_NOENC #endif + .fill KAISER_USER_PGD_FILL,8,0 NEXT_PAGE(early_dynamic_pgts) .fill 512*EARLY_DYNAMIC_PAGE_TABLES,8,0 @@ -379,6 +393,7 @@ NEXT_PGD_PAGE(init_top_pgt) .org init_top_pgt + PGD_START_KERNEL*8, 0 /* (2^48-(2*1024*1024*1024))/(2^39) = 511 */ .quad level3_kernel_pgt - __START_KERNEL_map + _PAGE_TABLE_NOENC + .fill KAISER_USER_PGD_FILL,8,0 NEXT_PAGE(level3_ident_pgt) .quad level2_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE_NOENC @@ -391,6 +406,7 @@ NEXT_PAGE(level2_ident_pgt) #else NEXT_PGD_PAGE(init_top_pgt) .fill 512,8,0 + .fill KAISER_USER_PGD_FILL,8,0 #endif #ifdef CONFIG_X86_5LEVEL _