From patchwork Tue Oct 3 06:24:53 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Li, Xin3" X-Patchwork-Id: 13406926 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 lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 31C1CE7542D for ; Tue, 3 Oct 2023 07:07:08 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.612004.951891 (Exim 4.92) (envelope-from ) id 1qnZUe-0001Xy-Nx; Tue, 03 Oct 2023 07:06:56 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 612004.951891; Tue, 03 Oct 2023 07:06:56 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1qnZUe-0001XS-G6; Tue, 03 Oct 2023 07:06:56 +0000 Received: by outflank-mailman (input) for mailman id 612004; Tue, 03 Oct 2023 07:06:54 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1qnZJC-00047B-95 for xen-devel@lists.xenproject.org; Tue, 03 Oct 2023 06:55:06 +0000 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.126]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id c53ed50d-61b9-11ee-9b0d-b553b5be7939; Tue, 03 Oct 2023 08:55:00 +0200 (CEST) Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Oct 2023 23:54:51 -0700 Received: from unknown (HELO fred..) ([172.25.112.68]) by fmsmga005.fm.intel.com with ESMTP; 02 Oct 2023 23:54:50 -0700 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: c53ed50d-61b9-11ee-9b0d-b553b5be7939 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1696316100; x=1727852100; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=/UldAmuJEnsflYS2+cyLAQ4E+J1yAKX8pToUnF0eneI=; b=AxM3ClgOBxtrGOMWVpzjvmsA3Dg4oD8RXQ8GLcMX+h/icwju5qHpfXGO c8NpR2wG5dXU7hbTQDbAiJnzq2DSSZnyZ+6oFH4UveYw2xJ4qm/H0bzAh qUa1UmM6sR7l0iLeXPskJEmQ6vge4oUKryiIG56eenSA9uMZUWGcKa9NE hAPHGO2Wajae0ZYrscKpuoe0HGuvhsC+KiVuNJMC7XntdCmUXTU7AsSP8 rsHiPfEH2ll+P/jKtAUjE6Jtt69QopY8WjG12meJvvFf7B4Upj8TYWS2F 2vjwA4Im10W2mAMvblnVT7ooAKd9cehJZB/4RAjtaOTaqbpzW9wazd0Al w==; X-IronPort-AV: E=McAfee;i="6600,9927,10851"; a="367858305" X-IronPort-AV: E=Sophos;i="6.03,196,1694761200"; d="scan'208";a="367858305" X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10851"; a="1081901004" X-IronPort-AV: E=Sophos;i="6.03,196,1694761200"; d="scan'208";a="1081901004" From: Xin Li To: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, kvm@vger.kernel.org, xen-devel@lists.xenproject.org Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, luto@kernel.org, pbonzini@redhat.com, seanjc@google.com, peterz@infradead.org, jgross@suse.com, ravi.v.shankar@intel.com, mhiramat@kernel.org, andrew.cooper3@citrix.com, jiangshanlai@gmail.com, nik.borisov@suse.com Subject: [PATCH v12 32/37] x86/entry/calling: Allow PUSH_AND_CLEAR_REGS being used beyond actual entry code Date: Mon, 2 Oct 2023 23:24:53 -0700 Message-Id: <20231003062458.23552-33-xin3.li@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231003062458.23552-1-xin3.li@intel.com> References: <20231003062458.23552-1-xin3.li@intel.com> MIME-Version: 1.0 From: "Peter Zijlstra (Intel)" PUSH_AND_CLEAR_REGS could be used besides actual entry code; in that case %rbp shouldn't be cleared (otherwise the frame pointer is destroyed) and UNWIND_HINT shouldn't be added. Signed-off-by: Peter Zijlstra (Intel) Tested-by: Shan Kang Signed-off-by: Xin Li --- arch/x86/entry/calling.h | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h index f6907627172b..eb57c023d5df 100644 --- a/arch/x86/entry/calling.h +++ b/arch/x86/entry/calling.h @@ -65,7 +65,7 @@ For 32-bit we have the following conventions - kernel is built with * for assembly code: */ -.macro PUSH_REGS rdx=%rdx rcx=%rcx rax=%rax save_ret=0 +.macro PUSH_REGS rdx=%rdx rcx=%rcx rax=%rax save_ret=0 unwind_hint=1 .if \save_ret pushq %rsi /* pt_regs->si */ movq 8(%rsp), %rsi /* temporarily store the return address in %rsi */ @@ -87,14 +87,17 @@ For 32-bit we have the following conventions - kernel is built with pushq %r13 /* pt_regs->r13 */ pushq %r14 /* pt_regs->r14 */ pushq %r15 /* pt_regs->r15 */ + + .if \unwind_hint UNWIND_HINT_REGS + .endif .if \save_ret pushq %rsi /* return address on top of stack */ .endif .endm -.macro CLEAR_REGS +.macro CLEAR_REGS clear_bp=1 /* * Sanitize registers of values that a speculation attack might * otherwise want to exploit. The lower registers are likely clobbered @@ -109,7 +112,9 @@ For 32-bit we have the following conventions - kernel is built with xorl %r10d, %r10d /* nospec r10 */ xorl %r11d, %r11d /* nospec r11 */ xorl %ebx, %ebx /* nospec rbx */ + .if \clear_bp xorl %ebp, %ebp /* nospec rbp */ + .endif xorl %r12d, %r12d /* nospec r12 */ xorl %r13d, %r13d /* nospec r13 */ xorl %r14d, %r14d /* nospec r14 */ @@ -117,9 +122,9 @@ For 32-bit we have the following conventions - kernel is built with .endm -.macro PUSH_AND_CLEAR_REGS rdx=%rdx rcx=%rcx rax=%rax save_ret=0 - PUSH_REGS rdx=\rdx, rcx=\rcx, rax=\rax, save_ret=\save_ret - CLEAR_REGS +.macro PUSH_AND_CLEAR_REGS rdx=%rdx rcx=%rcx rax=%rax save_ret=0 clear_bp=1 unwind_hint=1 + PUSH_REGS rdx=\rdx, rcx=\rcx, rax=\rax, save_ret=\save_ret unwind_hint=\unwind_hint + CLEAR_REGS clear_bp=\clear_bp .endm .macro POP_REGS pop_rdi=1