From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f71.google.com (mail-pg0-f71.google.com [74.125.83.71]) by kanga.kvack.org (Postfix) with ESMTP id 39B0A440D2B for ; Fri, 10 Nov 2017 14:31:47 -0500 (EST) Received: by mail-pg0-f71.google.com with SMTP id r18so10036514pgu.9 for ; Fri, 10 Nov 2017 11:31:47 -0800 (PST) Received: from mga05.intel.com (mga05.intel.com. [192.55.52.43]) by mx.google.com with ESMTPS id h7si6423088pgq.512.2017.11.10.11.31.46 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 10 Nov 2017 11:31:46 -0800 (PST) Subject: [PATCH 13/30] x86, kaiser: map dynamically-allocated LDTs From: Dave Hansen Date: Fri, 10 Nov 2017 11:31:27 -0800 References: <20171110193058.BECA7D88@viggo.jf.intel.com> In-Reply-To: <20171110193058.BECA7D88@viggo.jf.intel.com> Message-Id: <20171110193127.91345C5E@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, richard.fellner@student.tugraz.at, luto@kernel.org, torvalds@linux-foundation.org, keescook@google.com, hughd@google.com, x86@kernel.org From: Dave Hansen Normally, a process has a NULL mm->context.ldt. But, there is a syscall for a process to set a new one. If a process does that, the LDT be mapped into the user page tables, just like the default copy. The original KAISER patch missed this case. 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/ldt.c | 25 ++++++++++++++++++++----- 1 file changed, 20 insertions(+), 5 deletions(-) diff -puN arch/x86/kernel/ldt.c~kaiser-user-map-new-ldts arch/x86/kernel/ldt.c --- a/arch/x86/kernel/ldt.c~kaiser-user-map-new-ldts 2017-11-10 11:22:12.127244942 -0800 +++ b/arch/x86/kernel/ldt.c 2017-11-10 11:22:12.131244942 -0800 @@ -10,6 +10,7 @@ #include #include #include +#include #include #include #include @@ -56,11 +57,21 @@ static void flush_ldt(void *__mm) refresh_ldt_segments(); } +static void __free_ldt_struct(struct ldt_struct *ldt) +{ + if (ldt->nr_entries * LDT_ENTRY_SIZE > PAGE_SIZE) + vfree_atomic(ldt->entries); + else + free_page((unsigned long)ldt->entries); + kfree(ldt); +} + /* The caller must call finalize_ldt_struct on the result. LDT starts zeroed. */ static struct ldt_struct *alloc_ldt_struct(unsigned int num_entries) { struct ldt_struct *new_ldt; unsigned int alloc_size; + int ret; if (num_entries > LDT_ENTRIES) return NULL; @@ -88,6 +99,12 @@ static struct ldt_struct *alloc_ldt_stru return NULL; } + ret = kaiser_add_mapping((unsigned long)new_ldt->entries, alloc_size, + __PAGE_KERNEL | _PAGE_GLOBAL); + if (ret) { + __free_ldt_struct(new_ldt); + return NULL; + } new_ldt->nr_entries = num_entries; return new_ldt; } @@ -114,12 +131,10 @@ static void free_ldt_struct(struct ldt_s if (likely(!ldt)) return; + kaiser_remove_mapping((unsigned long)ldt->entries, + ldt->nr_entries * LDT_ENTRY_SIZE); paravirt_free_ldt(ldt->entries, ldt->nr_entries); - if (ldt->nr_entries * LDT_ENTRY_SIZE > PAGE_SIZE) - vfree_atomic(ldt->entries); - else - free_page((unsigned long)ldt->entries); - kfree(ldt); + __free_ldt_struct(ldt); } /* _ -- 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