From patchwork Tue Mar 3 22:12:01 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arvind Sankar X-Patchwork-Id: 206491 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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, 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 A6F31C3F2C6 for ; Tue, 3 Mar 2020 22:12:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5F62420870 for ; Tue, 3 Mar 2020 22:12:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727802AbgCCWMV (ORCPT ); Tue, 3 Mar 2020 17:12:21 -0500 Received: from mail-qk1-f194.google.com ([209.85.222.194]:35168 "EHLO mail-qk1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727311AbgCCWMI (ORCPT ); Tue, 3 Mar 2020 17:12:08 -0500 Received: by mail-qk1-f194.google.com with SMTP id 145so5136598qkl.2; Tue, 03 Mar 2020 14:12:07 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=Nxp2N/+qPhL2jiuGrf5UBDCZbk70psISz/K4zJ0PBCM=; b=I6B/gYuc08FDlIAvyE7FDZm1NSQEFykwPxaWHvv09QnYGFg+ggd2znyVBKXcpIH2RN k+BddmnpihMIwI5WF9d7yQM/B3RYVAFcXRibbnznMMSKkGGFyfKY5QWG2h/vPJ59zJJd ar90BN6Hg6VTGwNBI/+M1ca9ArfjKcmcpG/bEs5WN46Jo96OewHbyZZiyfE0FuLu9G3g Zxbisc5YooG0q4qCYpVxuY8Jvni7waLXvlMVbA+bUpBdIX6qkiFilshTjJQ58cV2fKRv PL62GEm/1nbg10A+aouYwixcHil/NmNCNuRKxgcII+//FRw8DFDSHwI8jb5nf4O/mQUA p9Ng== X-Gm-Message-State: ANhLgQ26WaqM6cjo1PGXFb1LCcfIkRQ0PWlS2hU1Nroa7HH02iCzhXWD evS53bxSjf9wo2NfeN7ol1Th3bYfHQY= X-Google-Smtp-Source: ADFU+vtIih8zsflAoNyN4lfdYEWlNJBCM7hnC6wjtyCOoPYNltvZ+m9D4jZc3zeWbkJIss6hMxbexQ== X-Received: by 2002:a05:620a:1186:: with SMTP id b6mr191181qkk.59.1583273527108; Tue, 03 Mar 2020 14:12:07 -0800 (PST) Received: from rani.riverdale.lan ([2001:470:1f07:5f3::b55f]) by smtp.gmail.com with ESMTPSA id i91sm13267378qtd.70.2020.03.03.14.12.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 03 Mar 2020 14:12:06 -0800 (PST) From: Arvind Sankar To: Ard Biesheuvel Cc: linux-efi@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 1/5] x86/boot/compressed/32: Save the output address instead of recalculating it Date: Tue, 3 Mar 2020 17:12:01 -0500 Message-Id: <20200303221205.4048668-2-nivedita@alum.mit.edu> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200303221205.4048668-1-nivedita@alum.mit.edu> References: <20200301230537.2247550-1-nivedita@alum.mit.edu> <20200303221205.4048668-1-nivedita@alum.mit.edu> MIME-Version: 1.0 Sender: linux-efi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org In preparation for being able to decompress into a buffer starting at a different address than startup_32, save the calculated output address instead of recalculating it later. We now keep track of three addresses: %edx: startup_32 as we were loaded by bootloader %ebx: new location of compressed kernel %ebp: start of decompression buffer Signed-off-by: Arvind Sankar --- arch/x86/boot/compressed/head_32.S | 25 ++++++++++++------------- 1 file changed, 12 insertions(+), 13 deletions(-) diff --git a/arch/x86/boot/compressed/head_32.S b/arch/x86/boot/compressed/head_32.S index 46bbe7ab4adf..894182500606 100644 --- a/arch/x86/boot/compressed/head_32.S +++ b/arch/x86/boot/compressed/head_32.S @@ -75,11 +75,11 @@ SYM_FUNC_START(startup_32) */ leal (BP_scratch+4)(%esi), %esp call 1f -1: popl %ebp - subl $1b, %ebp +1: popl %edx + subl $1b, %edx /* Load new GDT */ - leal gdt(%ebp), %eax + leal gdt(%edx), %eax movl %eax, 2(%eax) lgdt (%eax) @@ -92,13 +92,14 @@ SYM_FUNC_START(startup_32) movl %eax, %ss /* - * %ebp contains the address we are loaded at by the boot loader and %ebx + * %edx contains the address we are loaded at by the boot loader and %ebx * contains the address where we should move the kernel image temporarily - * for safe in-place decompression. + * for safe in-place decompression. %ebp contains the address that the kernel + * will be decompressed to. */ #ifdef CONFIG_RELOCATABLE - movl %ebp, %ebx + movl %edx, %ebx movl BP_kernel_alignment(%esi), %eax decl %eax addl %eax, %ebx @@ -110,10 +111,10 @@ SYM_FUNC_START(startup_32) movl $LOAD_PHYSICAL_ADDR, %ebx 1: + movl %ebx, %ebp // Save the output address for later /* Target address to relocate to for decompression */ - movl BP_init_size(%esi), %eax - subl $_end, %eax - addl %eax, %ebx + addl BP_init_size(%esi), %ebx + subl $_end, %ebx /* Set up the stack */ leal boot_stack_end(%ebx), %esp @@ -127,7 +128,7 @@ SYM_FUNC_START(startup_32) * where decompression in place becomes safe. */ pushl %esi - leal (_bss-4)(%ebp), %esi + leal (_bss-4)(%edx), %esi leal (_bss-4)(%ebx), %edi movl $(_bss - startup_32), %ecx shrl $2, %ecx @@ -196,9 +197,7 @@ SYM_FUNC_START_LOCAL_NOALIGN(.Lrelocated) /* push arguments for extract_kernel: */ pushl $z_output_len /* decompressed length, end of relocs */ - leal _end(%ebx), %eax - subl BP_init_size(%esi), %eax - pushl %eax /* output address */ + pushl %ebp /* output address */ pushl $z_input_len /* input_len */ leal input_data(%ebx), %eax