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 86344C433EF for ; Fri, 22 Jul 2022 09:08:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234049AbiGVJIn (ORCPT ); Fri, 22 Jul 2022 05:08:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36282 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232299AbiGVJI0 (ORCPT ); Fri, 22 Jul 2022 05:08:26 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 10F6782FBA; Fri, 22 Jul 2022 02:08:25 -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 ams.source.kernel.org (Postfix) with ESMTPS id B1D11B827BC; Fri, 22 Jul 2022 09:08:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 20F48C341C6; Fri, 22 Jul 2022 09:08:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1658480902; bh=Az7tafjlMAHHUibJrTHvA+4CWrMRaYbgi8eIJ5nAc2E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nfLzmtmV20H0Iv03A27bERnKVY1rNb0l2Lq2MuMgDqmm8V8wQAKdbJL93QbEFt1yy YTi/uD4IZ/gK2PxS1y4+7W+ZSVmyPHwX25JvigOfQnTtuqhXXgTn1m5vCjY67ozsta zLcgezZTXmJtnK89WuOw+GukY1p+s0CoOUw3vOIs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lai Jiangshan , Borislav Petkov , Juergen Gross , Thadeu Lima de Souza Cascardo Subject: [PATCH 5.18 03/70] x86/entry: Move PUSH_AND_CLEAR_REGS out of error_entry() Date: Fri, 22 Jul 2022 11:06:58 +0200 Message-Id: <20220722090650.913242285@linuxfoundation.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20220722090650.665513668@linuxfoundation.org> References: <20220722090650.665513668@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: Lai Jiangshan commit ee774dac0da1543376a69fd90840af6aa86879b3 upstream. The macro idtentry() (through idtentry_body()) calls error_entry() unconditionally even on XENPV. But XENPV needs to only push and clear regs. PUSH_AND_CLEAR_REGS in error_entry() makes the stack not return to its original place when the function returns, which means it is not possible to convert it to a C function. Carve out PUSH_AND_CLEAR_REGS out of error_entry() and into a separate function and call it before error_entry() in order to avoid calling error_entry() on XENPV. It will also allow for error_entry() to be converted to C code that can use inlined sync_regs() and save a function call. [ bp: Massage commit message. ] Signed-off-by: Lai Jiangshan Signed-off-by: Borislav Petkov Reviewed-by: Juergen Gross Link: https://lore.kernel.org/r/20220503032107.680190-4-jiangshanlai@gmail.com Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Greg Kroah-Hartman --- arch/x86/entry/entry_64.S | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -318,6 +318,14 @@ SYM_CODE_END(ret_from_fork) #endif .endm +/* Save all registers in pt_regs */ +SYM_CODE_START_LOCAL(push_and_clear_regs) + UNWIND_HINT_FUNC + PUSH_AND_CLEAR_REGS save_ret=1 + ENCODE_FRAME_POINTER 8 + RET +SYM_CODE_END(push_and_clear_regs) + /** * idtentry_body - Macro to emit code calling the C function * @cfunc: C function to be called @@ -325,6 +333,9 @@ SYM_CODE_END(ret_from_fork) */ .macro idtentry_body cfunc has_error_code:req + call push_and_clear_regs + UNWIND_HINT_REGS + call error_entry movq %rax, %rsp /* switch to the task stack if from userspace */ ENCODE_FRAME_POINTER @@ -986,13 +997,11 @@ SYM_CODE_START_LOCAL(paranoid_exit) SYM_CODE_END(paranoid_exit) /* - * Save all registers in pt_regs, and switch GS if needed. + * Switch GS and CR3 if needed. */ SYM_CODE_START_LOCAL(error_entry) UNWIND_HINT_FUNC cld - PUSH_AND_CLEAR_REGS save_ret=1 - ENCODE_FRAME_POINTER 8 testb $3, CS+8(%rsp) jz .Lerror_kernelspace