From patchwork Mon Apr 13 16:21:35 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 206418 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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, 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 6C1B0C2BA19 for ; Mon, 13 Apr 2020 16:21:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4A79220732 for ; Mon, 13 Apr 2020 16:21:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586794917; bh=yaoIwi+Ux7uaWMr1LOXjqVIdnt6J1WFg3Howl+bvQKc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=IB2pjUbjCooxmF5IEUVAO0lA4b4X5u+GESYeQ0KJPG/vi39qzDfxLZq1Canv2Q8Cw 92q6l6gsLthBBs1sLypfJnGuVIRQjeNmby0nBQnjNQaWrQdyEJOzq4s/GK2mt4t/ZX ZkKyFbYGU8LgoB8lhHhvTPhw0gF28wNBQURGBpxk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731471AbgDMQV5 (ORCPT ); Mon, 13 Apr 2020 12:21:57 -0400 Received: from mail.kernel.org ([198.145.29.99]:49018 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731410AbgDMQV4 (ORCPT ); Mon, 13 Apr 2020 12:21:56 -0400 Received: from e123331-lin.home (amontpellier-657-1-18-247.w109-210.abo.wanadoo.fr [109.210.65.247]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2B10D20678; Mon, 13 Apr 2020 16:21:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586794915; bh=yaoIwi+Ux7uaWMr1LOXjqVIdnt6J1WFg3Howl+bvQKc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CeB0Zi5AqGuX9YBhTOBuuFfSwB4ikdJolQ1jYDXvWM1bQppsbG2S5eilR6ZOt92u4 h7bk01YAAnDRag7JeYZVScThn5vKv+lsJ4hrAk8sqCTQp33eDixYyUSr7Bko85MM25 Mq0ajwOSBza1MIy77OqfkKEEIEdyjmbhjxCS9ADM= From: Ard Biesheuvel To: linux-efi@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org, Ard Biesheuvel , Geert Uytterhoeven , Nicolas Pitre , Linus Walleij , Russell King Subject: [PATCH v2 5/5] ARM: decompressor: run decompressor in place if loaded via UEFI Date: Mon, 13 Apr 2020 18:21:35 +0200 Message-Id: <20200413162135.14955-6-ardb@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200413162135.14955-1-ardb@kernel.org> References: <20200413162135.14955-1-ardb@kernel.org> Sender: linux-efi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org The decompressor can load from anywhere in memory, and the only reason the EFI stub code relocates it is to ensure it appears within the first 128 MiB of memory, so that the uncompressed kernel ends up at the right offset in memory. We can short circuit this, and simply jump into the decompressor startup code at the point where it knows where the base of memory lives. This also means there is no need to disable the MMU and caches, create new page tables and re-enable them. Signed-off-by: Ard Biesheuvel --- arch/arm/boot/compressed/head.S | 37 +++++----------- drivers/firmware/efi/libstub/arm32-stub.c | 45 +++----------------- 2 files changed, 17 insertions(+), 65 deletions(-) diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S index 9dea394b286b..4ec07c98f9b1 100644 --- a/arch/arm/boot/compressed/head.S +++ b/arch/arm/boot/compressed/head.S @@ -1480,37 +1480,22 @@ reloc_code_end: #ifdef CONFIG_EFI_STUB ENTRY(efi_enter_kernel) - mov r7, r0 @ preserve image base - mov r4, r1 @ preserve DT pointer + mov r4, r0 @ preserve image base + mov r8, r1 @ preserve DT pointer - mov r0, r4 @ DT start - add r1, r4, r2 @ DT end + mov r0, r8 @ DT start + add r1, r8, r2 @ DT end bl cache_clean_flush - mov r0, r7 @ relocated zImage - ldr r1, =_edata @ size of zImage - add r1, r1, r0 @ end of zImage - bl cache_clean_flush - - @ The PE/COFF loader might not have cleaned the code we are - @ running beyond the PoU, and so calling cache_off below from - @ inside the PE/COFF loader allocated region is unsafe unless - @ we explicitly clean it to the PoC. - adr r0, call_cache_fn @ region of code we will - adr r1, 0f @ run with MMU off - bl cache_clean_flush - bl cache_off + adr r0, 0f @ switch to our stack + ldr sp, [r0] + add sp, sp, r0 - @ Set parameters for booting zImage according to boot protocol - @ put FDT address in r2, it was returned by efi_entry() - @ r1 is the machine type, and r0 needs to be 0 - mov r0, #0 - mov r1, #0xFFFFFFFF - mov r2, r4 - add r7, r7, #(__efi_start - start) - mov pc, r7 @ no mode switch + mov r5, #0 @ appended DTB size + mov r7, #0xFFFFFFFF @ machine ID + b wont_overwrite ENDPROC(efi_enter_kernel) -0: +0: .long .L_user_stack_end - . #endif .align diff --git a/drivers/firmware/efi/libstub/arm32-stub.c b/drivers/firmware/efi/libstub/arm32-stub.c index 7826553af2ba..0050d811bf20 100644 --- a/drivers/firmware/efi/libstub/arm32-stub.c +++ b/drivers/firmware/efi/libstub/arm32-stub.c @@ -199,14 +199,8 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, unsigned long kernel_base; efi_status_t status; - /* - * Verify that the DRAM base address is compatible with the ARM - * boot protocol, which determines the base of DRAM by masking - * off the low 27 bits of the address at which the zImage is - * loaded. These assumptions are made by the decompressor, - * before any memory map is available. - */ - kernel_base = round_up(dram_base, SZ_128M); + /* use a 16 MiB aligned base for the decompressed kernel */ + kernel_base = round_up(dram_base, SZ_16M) + TEXT_OFFSET; /* * Note that some platforms (notably, the Raspberry Pi 2) put @@ -215,41 +209,14 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, * base of the kernel image is only partially used at the moment. * (Up to 5 pages are used for the swapper page tables) */ - kernel_base += TEXT_OFFSET - 5 * PAGE_SIZE; - - status = reserve_kernel_base(kernel_base, reserve_addr, reserve_size); + status = reserve_kernel_base(kernel_base - 5 * PAGE_SIZE, reserve_addr, + reserve_size); if (status != EFI_SUCCESS) { pr_efi_err("Unable to allocate memory for uncompressed kernel.\n"); return status; } - /* - * Relocate the zImage, so that it appears in the lowest 128 MB - * memory window. - */ - *image_addr = (unsigned long)image->image_base; - *image_size = image->image_size; - status = efi_relocate_kernel(image_addr, *image_size, *image_size, - kernel_base + MAX_UNCOMP_KERNEL_SIZE, 0, 0); - if (status != EFI_SUCCESS) { - pr_efi_err("Failed to relocate kernel.\n"); - efi_free(*reserve_size, *reserve_addr); - *reserve_size = 0; - return status; - } - - /* - * Check to see if we were able to allocate memory low enough - * in memory. The kernel determines the base of DRAM from the - * address at which the zImage is loaded. - */ - if (*image_addr + *image_size > dram_base + ZIMAGE_OFFSET_LIMIT) { - pr_efi_err("Failed to relocate kernel, no low memory available.\n"); - efi_free(*reserve_size, *reserve_addr); - *reserve_size = 0; - efi_free(*image_size, *image_addr); - *image_size = 0; - return EFI_LOAD_ERROR; - } + *image_addr = kernel_base; + *image_size = 0; return EFI_SUCCESS; }