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=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 72A8FC433E0 for ; Tue, 2 Mar 2021 10:29:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 34BC164F0A for ; Tue, 2 Mar 2021 10:29:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1380023AbhCBK0R (ORCPT ); Tue, 2 Mar 2021 05:26:17 -0500 Received: from mail.kernel.org ([198.145.29.99]:55120 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349559AbhCBKFH (ORCPT ); Tue, 2 Mar 2021 05:05:07 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id CB73A64F16; Tue, 2 Mar 2021 10:04:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1614679466; bh=15SwaZ/8rrN2waOzJF7Zw5ICoWR5Pn4pn67kuMqXsIc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ABO9P5KTXvSfK5lusGZVnliPLUTf+U4T02/6GEhpj8IrDuhujOJj//0s5atDVq4O5 YvBINr+hlj/FlCpxmp7r/Nzj1+3ZcMTO79qig9YSYlzOjsEKDnlKpMKip5UetleRmS xPQviVpaGF7/M8cE6/+jFzTkdgj+juT4q1kMtaCZTiXmunYIr1YDIq/pjNZd7EdIL4 JIauPdohVhQpwb9Ups3l3pFYQ7QGgA/LYSdSSOtKq1lFAjGKBk6ySZOOF+teXFbzzZ p62E7atkEWw7KrruqdVsRiC8Mi+xlgTalHxA+VfejBmBF9ZCFdERgCHgz7Pj0HfdDQ 484WQU36FbsRw== From: Mike Rapoport To: x86@kernel.org Cc: Andrew Morton , Andrea Arcangeli , Baoquan He , Borislav Petkov , David Hildenbrand , "H. Peter Anvin" , Ingo Molnar , Mel Gorman , Michal Hocko , Mike Rapoport , Mike Rapoport , Qian Cai , Thomas Gleixner , Vlastimil Babka , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Borislav Petkov Subject: [PATCH v3 1/2] x86/setup: consolidate early memory reservations Date: Tue, 2 Mar 2021 12:04:05 +0200 Message-Id: <20210302100406.22059-2-rppt@kernel.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20210302100406.22059-1-rppt@kernel.org> References: <20210302100406.22059-1-rppt@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Mike Rapoport The early reservations of memory areas used by the firmware, bootloader, kernel text and data are spread over setup_arch(). Moreover, some of them happen *after* memblock allocations, e.g trim_platform_memory_ranges() and trim_low_memory_range() are called after reserve_real_mode() that allocates memory. There was no corruption of these memory regions because memblock always allocates memory either from the end of memory (in top-down mode) or above the kernel image (in bottom-up mode). However, the bottom up mode is going to be updated to span the entire memory [1] to avoid limitations caused by KASLR. Consolidate early memory reservations in a dedicated function to improve robustness against future changes. Having the early reservations in one place also makes it clearer what memory must be reserved before we allow memblock allocations. [1] https://lore.kernel.org/lkml/20201217201214.3414100-2-guro@fb.com Signed-off-by: Mike Rapoport Acked-by: Borislav Petkov --- arch/x86/kernel/setup.c | 92 ++++++++++++++++++++--------------------- 1 file changed, 44 insertions(+), 48 deletions(-) diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index d883176ef2ce..3e3c6036b023 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -645,18 +645,6 @@ static void __init trim_snb_memory(void) } } -/* - * Here we put platform-specific memory range workarounds, i.e. - * memory known to be corrupt or otherwise in need to be reserved on - * specific platforms. - * - * If this gets used more widely it could use a real dispatch mechanism. - */ -static void __init trim_platform_memory_ranges(void) -{ - trim_snb_memory(); -} - static void __init trim_bios_range(void) { /* @@ -729,7 +717,38 @@ static void __init trim_low_memory_range(void) { memblock_reserve(0, ALIGN(reserve_low, PAGE_SIZE)); } - + +static void __init early_reserve_memory(void) +{ + /* + * Reserve the memory occupied by the kernel between _text and + * __end_of_kernel_reserve symbols. Any kernel sections after the + * __end_of_kernel_reserve symbol must be explicitly reserved with a + * separate memblock_reserve() or they will be discarded. + */ + memblock_reserve(__pa_symbol(_text), + (unsigned long)__end_of_kernel_reserve - (unsigned long)_text); + + /* + * Make sure page 0 is always reserved because on systems with + * L1TF its contents can be leaked to user processes. + */ + memblock_reserve(0, PAGE_SIZE); + + early_reserve_initrd(); + + if (efi_enabled(EFI_BOOT)) + efi_memblock_x86_reserve_range(); + + memblock_x86_reserve_range_setup_data(); + + reserve_ibft_region(); + reserve_bios_regions(); + + trim_snb_memory(); + trim_low_memory_range(); +} + /* * Dump out kernel offset information on panic. */ @@ -764,29 +783,6 @@ dump_kernel_offset(struct notifier_block *self, unsigned long v, void *p) void __init setup_arch(char **cmdline_p) { - /* - * Reserve the memory occupied by the kernel between _text and - * __end_of_kernel_reserve symbols. Any kernel sections after the - * __end_of_kernel_reserve symbol must be explicitly reserved with a - * separate memblock_reserve() or they will be discarded. - */ - memblock_reserve(__pa_symbol(_text), - (unsigned long)__end_of_kernel_reserve - (unsigned long)_text); - - /* - * Make sure page 0 is always reserved because on systems with - * L1TF its contents can be leaked to user processes. - */ - memblock_reserve(0, PAGE_SIZE); - - early_reserve_initrd(); - - /* - * At this point everything still needed from the boot loader - * or BIOS or kernel text should be early reserved or marked not - * RAM in e820. All other memory is free game. - */ - #ifdef CONFIG_X86_32 memcpy(&boot_cpu_data, &new_cpu_data, sizeof(new_cpu_data)); @@ -910,8 +906,18 @@ void __init setup_arch(char **cmdline_p) parse_early_param(); - if (efi_enabled(EFI_BOOT)) - efi_memblock_x86_reserve_range(); + /* + * Do some memory reservations *before* memory is added to + * memblock, so memblock allocations won't overwrite it. + * Do it after early param, so we could get (unlikely) panic from + * serial. + * + * After this point everything still needed from the boot loader or + * firmware or kernel text should be early reserved or marked not + * RAM in e820. All other memory is free game. + */ + early_reserve_memory(); + #ifdef CONFIG_MEMORY_HOTPLUG /* * Memory used by the kernel cannot be hot-removed because Linux @@ -938,9 +944,6 @@ void __init setup_arch(char **cmdline_p) x86_report_nx(); - /* after early param, so could get panic from serial */ - memblock_x86_reserve_range_setup_data(); - if (acpi_mps_check()) { #ifdef CONFIG_X86_LOCAL_APIC disable_apic = 1; @@ -1032,8 +1035,6 @@ void __init setup_arch(char **cmdline_p) */ find_smp_config(); - reserve_ibft_region(); - early_alloc_pgt_buf(); /* @@ -1054,8 +1055,6 @@ void __init setup_arch(char **cmdline_p) */ sev_setup_arch(); - reserve_bios_regions(); - efi_fake_memmap(); efi_find_mirror(); efi_esrt_init(); @@ -1081,9 +1080,6 @@ void __init setup_arch(char **cmdline_p) reserve_real_mode(); - trim_platform_memory_ranges(); - trim_low_memory_range(); - init_mem_mapping(); idt_setup_early_pf(); -- 2.28.0