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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 51052C433F5 for ; Thu, 10 Mar 2022 14:12:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242745AbiCJOM7 (ORCPT ); Thu, 10 Mar 2022 09:12:59 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50536 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242808AbiCJOMh (ORCPT ); Thu, 10 Mar 2022 09:12:37 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 69E01154D04; Thu, 10 Mar 2022 06:10:54 -0800 (PST) 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 F183061B94; Thu, 10 Mar 2022 14:10:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 09487C36AE9; Thu, 10 Mar 2022 14:10:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646921453; bh=XWfPsTF81CkXJlNPj4xrj7j+Msen4QvmkKqcXNCg8eM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uvifsSloukgBviG//sR3CdXXKJLMp4RJN60C84ZkpgOSePEbxLADI0TCXw89630ah kJr/r5IU0g0oxjw2TZIv11AtK/F+bRLwBHD49NWgcTJacjnXlXXwn04XnBKrfQkz9K qtkYlCdIsFCrA0xh7iBI1aBkL5HgmT0/QB3EMPeI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Russell King (Oracle)" , Catalin Marinas , James Morse Subject: [PATCH 5.16 22/53] arm64: entry: Move the trampoline data page before the text page Date: Thu, 10 Mar 2022 15:09:27 +0100 Message-Id: <20220310140812.472410063@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220310140811.832630727@linuxfoundation.org> References: <20220310140811.832630727@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: James Morse commit c091fb6ae059cda563b2a4d93fdbc548ef34e1d6 upstream. The trampoline code has a data page that holds the address of the vectors, which is unmapped when running in user-space. This ensures that with CONFIG_RANDOMIZE_BASE, the randomised address of the kernel can't be discovered until after the kernel has been mapped. If the trampoline text page is extended to include multiple sets of vectors, it will be larger than a single page, making it tricky to find the data page without knowing the size of the trampoline text pages, which will vary with PAGE_SIZE. Move the data page to appear before the text page. This allows the data page to be found without knowing the size of the trampoline text pages. 'tramp_vectors' is used to refer to the beginning of the .entry.tramp.text section, do that explicitly. Reviewed-by: Russell King (Oracle) Reviewed-by: Catalin Marinas Signed-off-by: James Morse Signed-off-by: Greg Kroah-Hartman --- arch/arm64/include/asm/fixmap.h | 2 +- arch/arm64/kernel/entry.S | 9 +++++++-- 2 files changed, 8 insertions(+), 3 deletions(-) --- a/arch/arm64/include/asm/fixmap.h +++ b/arch/arm64/include/asm/fixmap.h @@ -62,8 +62,8 @@ enum fixed_addresses { #endif /* CONFIG_ACPI_APEI_GHES */ #ifdef CONFIG_UNMAP_KERNEL_AT_EL0 - FIX_ENTRY_TRAMP_DATA, FIX_ENTRY_TRAMP_TEXT, + FIX_ENTRY_TRAMP_DATA, #define TRAMP_VALIAS (__fix_to_virt(FIX_ENTRY_TRAMP_TEXT)) #endif /* CONFIG_UNMAP_KERNEL_AT_EL0 */ __end_of_permanent_fixed_addresses, --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -644,6 +644,11 @@ alternative_else_nop_endif */ .endm + .macro tramp_data_page dst + adr \dst, .entry.tramp.text + sub \dst, \dst, PAGE_SIZE + .endm + .macro tramp_ventry, regsize = 64 .align 7 1: @@ -660,7 +665,7 @@ alternative_else_nop_endif 2: tramp_map_kernel x30 #ifdef CONFIG_RANDOMIZE_BASE - adr x30, tramp_vectors + PAGE_SIZE + tramp_data_page x30 alternative_insn isb, nop, ARM64_WORKAROUND_QCOM_FALKOR_E1003 ldr x30, [x30] #else @@ -851,7 +856,7 @@ SYM_CODE_START(__sdei_asm_entry_trampoli 1: str x4, [x1, #(SDEI_EVENT_INTREGS + S_SDEI_TTBR1)] #ifdef CONFIG_RANDOMIZE_BASE - adr x4, tramp_vectors + PAGE_SIZE + tramp_data_page x4 add x4, x4, #:lo12:__sdei_asm_trampoline_next_handler ldr x4, [x4] #else