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 6293DC433F5 for ; Wed, 9 Mar 2022 16:22:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237992AbiCIQVN (ORCPT ); Wed, 9 Mar 2022 11:21:13 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47294 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234553AbiCIQMO (ORCPT ); Wed, 9 Mar 2022 11:12:14 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 77FEA149958; Wed, 9 Mar 2022 08:09:36 -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 ams.source.kernel.org (Postfix) with ESMTPS id 07919B8221D; Wed, 9 Mar 2022 16:09:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 704DEC340F5; Wed, 9 Mar 2022 16:09:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646842173; bh=mQatgqh/6NzDSIrRy2F06cmfP6PjNZfpbO5vp69JtKg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kJfYD9iFL0TyygUeLbPA7PoDprOUDsq7cnJfQVFtrt61bbYpnYsbFTkPhiU7Qoxn1 t5pnQ03iqkRsCkDvhlV4psSWus1k9dsm6l4r0QRhi0CSK5raoV0T39++t24t52VKwC T+N5OhRutkJSveOBxVi7nPmu20NXEut1yb026xzw= 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 23/37] arm64: entry: Allow tramp_alias to access symbols after the 4K boundary Date: Wed, 9 Mar 2022 17:00:24 +0100 Message-Id: <20220309155859.761424884@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220309155859.086952723@linuxfoundation.org> References: <20220309155859.086952723@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: linux-kernel@vger.kernel.org From: James Morse commit 6c5bf79b69f911560fbf82214c0971af6e58e682 upstream. Systems using kpti enter and exit the kernel through a trampoline mapping that is always mapped, even when the kernel is not. tramp_valias is a macro to find the address of a symbol in the trampoline mapping. Adding extra sets of vectors will expand the size of the entry.tramp.text section to beyond 4K. tramp_valias will be unable to generate addresses for symbols beyond 4K as it uses the 12 bit immediate of the add instruction. As there are now two registers available when tramp_alias is called, use the extra register to avoid the 4K limit of the 12 bit immediate. Reviewed-by: Russell King (Oracle) Reviewed-by: Catalin Marinas Signed-off-by: James Morse Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kernel/entry.S | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -103,9 +103,12 @@ .org .Lventry_start\@ + 128 // Did we overflow the ventry slot? .endm - .macro tramp_alias, dst, sym + .macro tramp_alias, dst, sym, tmp mov_q \dst, TRAMP_VALIAS - add \dst, \dst, #(\sym - .entry.tramp.text) + adr_l \tmp, \sym + add \dst, \dst, \tmp + adr_l \tmp, .entry.tramp.text + sub \dst, \dst, \tmp .endm /* @@ -429,10 +432,10 @@ alternative_else_nop_endif #ifdef CONFIG_UNMAP_KERNEL_AT_EL0 bne 4f msr far_el1, x29 - tramp_alias x30, tramp_exit_native + tramp_alias x30, tramp_exit_native, x29 br x30 4: - tramp_alias x30, tramp_exit_compat + tramp_alias x30, tramp_exit_compat, x29 br x30 #endif .else @@ -998,7 +1001,7 @@ alternative_if_not ARM64_UNMAP_KERNEL_AT alternative_else_nop_endif #ifdef CONFIG_UNMAP_KERNEL_AT_EL0 - tramp_alias dst=x5, sym=__sdei_asm_exit_trampoline + tramp_alias dst=x5, sym=__sdei_asm_exit_trampoline, tmp=x3 br x5 #endif SYM_CODE_END(__sdei_asm_handler)