From patchwork Mon Apr 11 09:48:08 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 559785 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 84ADAC433F5 for ; Mon, 11 Apr 2022 09:50:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344815AbiDKJwN (ORCPT ); Mon, 11 Apr 2022 05:52:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38066 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344863AbiDKJwB (ORCPT ); Mon, 11 Apr 2022 05:52:01 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1FF60419B6 for ; Mon, 11 Apr 2022 02:49:17 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id D25B361182 for ; Mon, 11 Apr 2022 09:49:16 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 515A7C385B0; Mon, 11 Apr 2022 09:49:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1649670556; bh=TEd74fUGGrd4Z1cRABQmAm27ke5FtcewQadVTliZWAk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=APCDKPvnrCFnc/yFQCpADw9E/+8oaOnTBY3oiuTMME/g2E5WUtw9Ug1Egx1RPyxzT EjiEzpbQnwpfVC2LZHJQELZoltQTiGPa0ghutlkMEVeZ6lKxHxlz56ookfqsAB8sZz Gnv4uVaYRmN+lyXILOrrys4CXZ6IZMfIDfGQBvM3T407gd8dgOl7nDJqtkBbqhl/fo bkYj//+mvVzGWLQCG5dcS5x2Rk8MFhWcyqXxQRAsASipW9n9tzrpdXKj6pAQuB1VhP b23fo96u8xrd/fH4Ba9cF7P87FnRomkI7XY541RnmtUGi/mjQUtb2Ik/wV4ufVS1LX k3qd3J3EdpHHA== From: Ard Biesheuvel To: linux-arm-kernel@lists.infradead.org Cc: linux-efi@vger.kernel.org, Ard Biesheuvel , Marc Zyngier , Will Deacon , Mark Rutland , Kees Cook , Catalin Marinas , Mark Brown Subject: [PATCH v3 14/30] arm64: head: create a temporary FDT mapping in the initial ID map Date: Mon, 11 Apr 2022 11:48:08 +0200 Message-Id: <20220411094824.4176877-15-ardb@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220411094824.4176877-1-ardb@kernel.org> References: <20220411094824.4176877-1-ardb@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3233; h=from:subject; bh=TEd74fUGGrd4Z1cRABQmAm27ke5FtcewQadVTliZWAk=; b=owEB7QES/pANAwAKAcNPIjmS2Y8kAcsmYgBiU/lMCk6FU1TDgS+d/bUIgpicu6zDRlE/gdeBj3bp /lk4Jn6JAbMEAAEKAB0WIQT72WJ8QGnJQhU3VynDTyI5ktmPJAUCYlP5TAAKCRDDTyI5ktmPJLGMC/ 9hBgnHrXB5qXx9kUoOG/jVi3qO3tUka8huOBorTeivyB/WXIQIn1ee8HVbMbsMvEA8nRkKkozI/YUR fEO5YHcy2EB0g/4cpFiHOyXBfR9AyYUmeV0BIbsMq3V+UbOkrA8OH5YmHU3uqZNaISOwCDOI5KEq2o /9X711XQ4DP0aWBdishsWkAa+lkqfeknOCGji8bePW6A0UZKrRbgio5Jl54RNN9CPL9jBnsC3NBG/Q +vsk+S4a6T9gGSpsY6XdQOB3KbxtHMV87+yQB5bauNvGMwlNg/nR+MDiK0GvE5+WUUfRCPkBSxE4oi y9H0W7xYC0E3RVbff4WmeiQVxAAFmKnELoApi8O5NwVCFRuyFpIO7HBKQrchQQIE7nbxqs+6UYZGG3 OufMrJhtuhYpHSDStTY1y1IRmlpZ4Je2O6dK2Mv6r+3MhY2455pxM26mX8VnLSS/9p3Z15tFWkl73Y PaZKpgB/CJZgjVU6vyaldd+9Jqk7BplYHIlmE1Q9pKBVE= X-Developer-Key: i=ardb@kernel.org; a=openpgp; fpr=F43D03328115A198C90016883D200E9CA6329909 Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org We need to access the DT very early to get at the command line and the KASLR seed, which currently means we rely on some hacks to call into the kernel before really calling into the kernel, which is undesirable. So instead, let's create a mapping for the FDT in the initial ID map, which is feasible now that it has been extended to cover more than a single page or block, and can be updated in place to remap other output addresses. Signed-off-by: Ard Biesheuvel --- arch/arm64/include/asm/kernel-pgtable.h | 6 ++++-- arch/arm64/kernel/head.S | 14 +++++++++++++- 2 files changed, 17 insertions(+), 3 deletions(-) diff --git a/arch/arm64/include/asm/kernel-pgtable.h b/arch/arm64/include/asm/kernel-pgtable.h index 5395e5a04f35..02e59fa8f293 100644 --- a/arch/arm64/include/asm/kernel-pgtable.h +++ b/arch/arm64/include/asm/kernel-pgtable.h @@ -8,6 +8,7 @@ #ifndef __ASM_KERNEL_PGTABLE_H #define __ASM_KERNEL_PGTABLE_H +#include #include #include @@ -88,10 +89,11 @@ /* the initial ID map may need two extra pages if it needs to be extended */ #if VA_BITS < 48 -#define INIT_IDMAP_DIR_SIZE (INIT_DIR_SIZE + (2 * PAGE_SIZE)) +#define INIT_IDMAP_DIR_SIZE ((INIT_IDMAP_DIR_PAGES + 2) * PAGE_SIZE) #else -#define INIT_IDMAP_DIR_SIZE INIT_DIR_SIZE +#define INIT_IDMAP_DIR_SIZE (INIT_IDMAP_DIR_PAGES * PAGE_SIZE) #endif +#define INIT_IDMAP_DIR_PAGES EARLY_PAGES(KIMAGE_VADDR, _end + MAX_FDT_SIZE + SWAPPER_BLOCK_SIZE) /* Initial memory map size */ #if ARM64_KERNEL_USES_PMD_MAPS diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index 2c491cac4871..bec3805c941c 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -82,6 +82,7 @@ * primary lowlevel boot path: * * Register Scope Purpose + * x19 create_idmap() .. __ start_kernel() ID map VA of the DT blob * x21 primary_entry() .. start_kernel() FDT pointer passed at boot in x0 * x23 primary_entry() .. start_kernel() physical misalignment/KASLR offset * x28 clear_page_tables() callee preserved temp register @@ -346,7 +347,7 @@ SYM_FUNC_START_LOCAL(create_idmap) #endif adrp x0, init_idmap_pg_dir adrp x3, _text - adrp x6, _end + adrp x6, _end + MAX_FDT_SIZE + SWAPPER_BLOCK_SIZE mov x7, SWAPPER_RX_MMUFLAGS map_memory x0, x1, x3, x6, x7, x3, IDMAP_PGD_ORDER, x10, x11, x12, x13, x14, EXTRA_SHIFT @@ -360,6 +361,17 @@ SYM_FUNC_START_LOCAL(create_idmap) mov x6, #SWAPPER_BLOCK_SHIFT bl remap_region + /* Remap the FDT read-only after the kernel image */ + adrp x1, _text + adrp x19, _end + SWAPPER_BLOCK_SIZE + bic x2, x19, #SWAPPER_BLOCK_SIZE - 1 + bfi x19, x21, #0, #SWAPPER_BLOCK_SHIFT // remapped FDT address + add x3, x2, #MAX_FDT_SIZE + SWAPPER_BLOCK_SIZE + bic x4, x21, #SWAPPER_BLOCK_SIZE - 1 + mov x5, SWAPPER_RX_MMUFLAGS + mov x6, #SWAPPER_BLOCK_SHIFT + bl remap_region + /* * Since the page tables have been populated with non-cacheable * accesses (MMU disabled), invalidate those tables again to