From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f197.google.com (mail-pf0-f197.google.com [209.85.192.197]) by kanga.kvack.org (Postfix) with ESMTP id D5A2E6B026D for ; Tue, 31 Oct 2017 18:32:06 -0400 (EDT) Received: by mail-pf0-f197.google.com with SMTP id t188so371631pfd.20 for ; Tue, 31 Oct 2017 15:32:06 -0700 (PDT) Received: from mga06.intel.com (mga06.intel.com. [134.134.136.31]) by mx.google.com with ESMTPS id g83si2735180pfg.161.2017.10.31.15.32.05 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 31 Oct 2017 15:32:05 -0700 (PDT) Subject: [PATCH 10/23] x86, kaiser: make sure static PGDs are 8k in size From: Dave Hansen Date: Tue, 31 Oct 2017 15:32:05 -0700 References: <20171031223146.6B47C861@viggo.jf.intel.com> In-Reply-To: <20171031223146.6B47C861@viggo.jf.intel.com> Message-Id: <20171031223205.951EFCB6@viggo.jf.intel.com> Sender: owner-linux-mm@kvack.org List-ID: 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, luto@kernel.org, torvalds@linux-foundation.org, keescook@google.com, hughd@google.com, x86@kernel.org We have a few PGDs that come out of the kernel binary instead of being allocated dynamically. Before this patch, they are all 8k-aligned, but we also need them to be 8k in *size*e 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: 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 2017-10-31 15:03:53.866279568 -0700 +++ b/arch/x86/kernel/head_64.S 2017-10-31 15:03:53.870279757 -0700 @@ -340,11 +340,24 @@ 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 */ @@ -363,6 +376,7 @@ 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 @@ -372,6 +386,7 @@ NEXT_PAGE(early_dynamic_pgts) #ifndef CONFIG_XEN NEXT_PGD_PAGE(init_top_pgt) .fill 512,8,0 + .fill KAISER_USER_PGD_FILL,8,0 #else NEXT_PGD_PAGE(init_top_pgt) .quad level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE_NOENC @@ -380,6 +395,7 @@ 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 _ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org