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 1760FC4332F for ; Thu, 24 Nov 2022 08:13:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229907AbiKXINM (ORCPT ); Thu, 24 Nov 2022 03:13:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57690 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229757AbiKXIMU (ORCPT ); Thu, 24 Nov 2022 03:12:20 -0500 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5B291ED702; Thu, 24 Nov 2022 00:12:05 -0800 (PST) Date: Thu, 24 Nov 2022 08:12:02 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1669277524; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=tbBDHp716dY21xd9DiuURl9WaCsgFsDzFg6Q+0Js6R0=; b=1cMgBrYF4P7xlQ02f7r+UvgIaeVtf3cNdR7tVM8tTPiSXAnV0/6wbr5K2UQY/b3gFb60DK f3Zs8LJDLBUeDk2Lq8PvLOIR01aEXV+jkqusiUGyEbCjEkd+fqaBbp5ofvdO28yFLzEVCJ qmJd0dTp/rzwP2fN7MkH+O9Ut7SHRMO9WZydgyopBZZJX834QR4MozLXGRYuTfKZiYaEus gNQA+NNFWS5tfxm58+InH5zuGpaW1LEfBdRscuUzRX+phgIl1Zx/KqSSaC7rPDKmc5niDy bc6rMEFGx6F6RxC/lE4C5z/EY7XEpz+2c0RjNXccLiF9LUXzwc3zaAg3cqS9KA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1669277524; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=tbBDHp716dY21xd9DiuURl9WaCsgFsDzFg6Q+0Js6R0=; b=4LUui1I53SCRnV+CQh14OOlKK04j1sIOaTTn1+w0fz+CDsVaqmtgl7cuasJLRuHhThKeb5 SGv7erhw3b8mkECw== From: "tip-bot2 for Ard Biesheuvel" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/boot] x86/boot/compressed: Move startup32_check_sev_cbit() into .text Cc: Ard Biesheuvel , Borislav Petkov , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20221122161017.2426828-14-ardb@kernel.org> References: <20221122161017.2426828-14-ardb@kernel.org> MIME-Version: 1.0 Message-ID: <166927752269.4906.18330426815751455059.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the x86/boot branch of tip: Commit-ID: b5d854cd4b6a314edd6c15dabc4233b84a0f8e5e Gitweb: https://git.kernel.org/tip/b5d854cd4b6a314edd6c15dabc4233b84a0f8e5e Author: Ard Biesheuvel AuthorDate: Tue, 22 Nov 2022 17:10:13 +01:00 Committer: Borislav Petkov CommitterDate: Thu, 24 Nov 2022 08:57:41 +01:00 x86/boot/compressed: Move startup32_check_sev_cbit() into .text Move startup32_check_sev_cbit() into the .text section and turn it into an ordinary function using the ordinary 32-bit calling convention, instead of saving/restoring the registers that are known to be live at the only call site. This improves maintainability, and makes it possible to move this function out of head_64.S and into a separate compilation unit that is specific to memory encryption. Note that this requires the call site to be moved before the mixed mode check, as %eax will be live otherwise. Signed-off-by: Ard Biesheuvel Signed-off-by: Borislav Petkov Link: https://lore.kernel.org/r/20221122161017.2426828-14-ardb@kernel.org --- arch/x86/boot/compressed/head_64.S | 35 +++++++++++++++-------------- 1 file changed, 19 insertions(+), 16 deletions(-) diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index 16cccc2..30ba541 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -251,6 +251,11 @@ SYM_FUNC_START(startup_32) movl $__BOOT_TSS, %eax ltr %ax +#ifdef CONFIG_AMD_MEM_ENCRYPT + /* Check if the C-bit position is correct when SEV is active */ + call startup32_check_sev_cbit +#endif + /* * Setup for the jump to 64bit mode * @@ -268,8 +273,6 @@ SYM_FUNC_START(startup_32) leal rva(startup_64_mixed_mode)(%ebp), %eax 1: #endif - /* Check if the C-bit position is correct when SEV is active */ - call startup32_check_sev_cbit pushl $__KERNEL_CS pushl %eax @@ -724,16 +727,17 @@ SYM_DATA_END_LABEL(boot_idt, SYM_L_GLOBAL, boot_idt_end) * succeed. An incorrect C-bit position will map all memory unencrypted, so that * the compare will use the encrypted random data and fail. */ - __HEAD -SYM_FUNC_START(startup32_check_sev_cbit) #ifdef CONFIG_AMD_MEM_ENCRYPT - pushl %eax + .text +SYM_FUNC_START(startup32_check_sev_cbit) pushl %ebx - pushl %ecx - pushl %edx + pushl %ebp + + call 0f +0: popl %ebp /* Check for non-zero sev_status */ - movl rva(sev_status)(%ebp), %eax + movl (sev_status - 0b)(%ebp), %eax testl %eax, %eax jz 4f @@ -748,17 +752,18 @@ SYM_FUNC_START(startup32_check_sev_cbit) jnc 2b /* Store to memory and keep it in the registers */ - movl %eax, rva(sev_check_data)(%ebp) - movl %ebx, rva(sev_check_data+4)(%ebp) + leal (sev_check_data - 0b)(%ebp), %ebp + movl %eax, 0(%ebp) + movl %ebx, 4(%ebp) /* Enable paging to see if encryption is active */ movl %cr0, %edx /* Backup %cr0 in %edx */ movl $(X86_CR0_PG | X86_CR0_PE), %ecx /* Enable Paging and Protected mode */ movl %ecx, %cr0 - cmpl %eax, rva(sev_check_data)(%ebp) + cmpl %eax, 0(%ebp) jne 3f - cmpl %ebx, rva(sev_check_data+4)(%ebp) + cmpl %ebx, 4(%ebp) jne 3f movl %edx, %cr0 /* Restore previous %cr0 */ @@ -770,13 +775,11 @@ SYM_FUNC_START(startup32_check_sev_cbit) jmp 3b 4: - popl %edx - popl %ecx + popl %ebp popl %ebx - popl %eax -#endif RET SYM_FUNC_END(startup32_check_sev_cbit) +#endif /* * Stack and heap for uncompression