From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-14.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CD1B9C433DF for ; Mon, 19 Oct 2020 19:45:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 68B5B222EA for ; Mon, 19 Oct 2020 19:45:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="HRmzgZDK"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="vpU8s1Fl" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731360AbgJSTpi (ORCPT ); Mon, 19 Oct 2020 15:45:38 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:33720 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731344AbgJSTp1 (ORCPT ); Mon, 19 Oct 2020 15:45:27 -0400 Date: Mon, 19 Oct 2020 19:44:43 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1603136685; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=sOdik0Y+lrIjbp3po9kuZpanyt1dLCgOmvmW4L9QxXc=; b=HRmzgZDKyOscl2E5rHcZd619yq7IuPKQJuooi/XoFySXh+ijo5fVVU5KpZ+0PEX6cxmJxT ikADryOZk8awOFYF+KvjXFQB/CmWC/L+1L6zEjSY3nXadTa6HUrOph0wuNyZeueyJVdnBA qorWZ0HNGYkxXwwBgBvGqgzwypxvFBzhP3m0HM+apeAcdPau3sstNI9JwK5FsOrellI3wE 5HOjY/KqJKMGZVONdmJYfLBG/dwlUa4UY0MFMpjvPfxsC5MB0SeUChItiHHjqoLI1Ur4Jk On2o74RPEXoVcH8TnTWfhw1lf9wBM2DWFZ6RNgG7J+09ZsUg1FW5sFbOA+VxbQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1603136685; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=sOdik0Y+lrIjbp3po9kuZpanyt1dLCgOmvmW4L9QxXc=; b=vpU8s1Fli+VpX6fb7t7cOVgj91hC4Z7BZD/VWWt7vy5/nffs0/ad5eXkuPGkxvJ7OgdbiR X/QdEHJRT7EGBQDA== From: "tip-bot2 for Arvind Sankar" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/seves] x86/boot/64: Explicitly map boot_params and command line Cc: Arvind Sankar , Borislav Petkov , Joerg Roedel , x86 , LKML In-Reply-To: <20201016200404.1615994-1-nivedita@alum.mit.edu> References: <20201016200404.1615994-1-nivedita@alum.mit.edu> MIME-Version: 1.0 Message-ID: <160313668395.7002.7778590955397923179.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the x86/seves branch of tip: Commit-ID: b17a45b6e53f6613118b2e5cfc4a992cc50deb2c Gitweb: https://git.kernel.org/tip/b17a45b6e53f6613118b2e5cfc4a992cc50deb2c Author: Arvind Sankar AuthorDate: Fri, 16 Oct 2020 16:04:01 -04:00 Committer: Borislav Petkov CommitterDate: Mon, 19 Oct 2020 19:39:50 +02:00 x86/boot/64: Explicitly map boot_params and command line Commits ca0e22d4f011 ("x86/boot/compressed/64: Always switch to own page table") 8570978ea030 ("x86/boot/compressed/64: Don't pre-map memory in KASLR code") set up a new page table in the decompressor stub, but without explicit mappings for boot_params and the kernel command line, relying on the #PF handler instead. This is fragile, as boot_params and the command line mappings are required for the main kernel. If EARLY_PRINTK and RANDOMIZE_BASE are disabled, a QEMU/OVMF boot never accesses the command line in the decompressor stub, and so it never gets mapped. The main kernel accesses it from the identity mapping if AMD_MEM_ENCRYPT is enabled, and will crash. Fix this by adding back the explicit mapping of boot_params and the command line. Note: the changes also removed the explicit mapping of the main kernel, with the result that .bss and .brk may not be in the identity mapping, but those don't get accessed by the main kernel before it switches to its own page tables. [ bp: Pass boot_params with a MOV %rsp... instead of PUSH/POP. Use block formatting for the comment. ] Signed-off-by: Arvind Sankar Signed-off-by: Borislav Petkov Reviewed-by: Joerg Roedel Link: https://lkml.kernel.org/r/20201016200404.1615994-1-nivedita@alum.mit.edu --- arch/x86/boot/compressed/head_64.S | 3 +++ arch/x86/boot/compressed/ident_map_64.c | 23 ++++++++++++++++++++--- 2 files changed, 23 insertions(+), 3 deletions(-) diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index 1c80f17..017de6c 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -544,6 +544,9 @@ SYM_FUNC_START_LOCAL_NOALIGN(.Lrelocated) pushq %rsi call set_sev_encryption_mask call load_stage2_idt + + /* Pass boot_params to initialize_identity_maps() */ + movq (%rsp), %rdi call initialize_identity_maps popq %rsi diff --git a/arch/x86/boot/compressed/ident_map_64.c b/arch/x86/boot/compressed/ident_map_64.c index c6f7aef..a5e5db6 100644 --- a/arch/x86/boot/compressed/ident_map_64.c +++ b/arch/x86/boot/compressed/ident_map_64.c @@ -33,6 +33,12 @@ #define __PAGE_OFFSET __PAGE_OFFSET_BASE #include "../../mm/ident_map.c" +#define _SETUP +#include /* For COMMAND_LINE_SIZE */ +#undef _SETUP + +extern unsigned long get_cmd_line_ptr(void); + /* Used by PAGE_KERN* macros: */ pteval_t __default_kernel_pte_mask __read_mostly = ~0; @@ -101,8 +107,10 @@ static void add_identity_map(unsigned long start, unsigned long end) } /* Locates and clears a region for a new top level page table. */ -void initialize_identity_maps(void) +void initialize_identity_maps(void *rmode) { + unsigned long cmdline; + /* Exclude the encryption mask from __PHYSICAL_MASK */ physical_mask &= ~sme_me_mask; @@ -143,10 +151,19 @@ void initialize_identity_maps(void) } /* - * New page-table is set up - map the kernel image and load it - * into cr3. + * New page-table is set up - map the kernel image, boot_params and the + * command line. The uncompressed kernel requires boot_params and the + * command line to be mapped in the identity mapping. Map them + * explicitly here in case the compressed kernel does not touch them, + * or does not touch all the pages covering them. */ add_identity_map((unsigned long)_head, (unsigned long)_end); + boot_params = rmode; + add_identity_map((unsigned long)boot_params, (unsigned long)(boot_params + 1)); + cmdline = get_cmd_line_ptr(); + add_identity_map(cmdline, cmdline + COMMAND_LINE_SIZE); + + /* Load the new page-table. */ write_cr3(top_level_pgt); }