From nobody Thu Apr 16 05:17:46 2026 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 086D4C4332F for ; Thu, 24 Nov 2022 08:13:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229880AbiKXINu (ORCPT ); Thu, 24 Nov 2022 03:13:50 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57816 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229851AbiKXIMm (ORCPT ); Thu, 24 Nov 2022 03:12:42 -0500 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2ED0BD9BBD; Thu, 24 Nov 2022 00:12:16 -0800 (PST) Date: Thu, 24 Nov 2022 08:12:13 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1669277534; 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=fPpimrJIQAMCF4lmI39uXhb9L9z/d6NKQTTeNn4maz4=; b=qH1yk0LQ1Mo/Oma7w7BMP19PtI/U96N61VxxCepYFupN3v4HEmm3/tcqNLaNDRCAfjDkN7 0D0ScK6NVGxe1GLspwlt1yzimp9hoNeQh5/qM0NVMHRl16ihrF7SV7Jd2F8/hL2s7BjAnJ VXty8vc8LtrMtkdlUXlnthczCjHhrxxpqsLv3g2JKAcnUwry384P5h6RnS7879UCSzSwob 5QvVYFAVn5dXrdplEv10wy+buceiRUA91OZmE1Dn6mrcHfgpzb7Zv868XOLSmvJUHnnc9H 0gN9VaB9AKdJeG6D6jHlUrGbSrGxo/BIBLEsLxs6YHW8lMc+yyAD8hO1pix+oA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1669277534; 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=fPpimrJIQAMCF4lmI39uXhb9L9z/d6NKQTTeNn4maz4=; b=zs7RhUL+PRCNXwRVLumyAmMfKOr1LPTd2b4BJnKtL41JkIR7GVCqTgYN7E+6eavJLck6k9 1uJxYkqOEDUki4AA== 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 bootargs parsing out of 32-bit startup code Cc: Ard Biesheuvel , Borislav Petkov , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20221122161017.2426828-4-ardb@kernel.org> References: <20221122161017.2426828-4-ardb@kernel.org> MIME-Version: 1.0 Message-ID: <166927753357.4906.8620289754967434462.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: quoted-printable 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: 5c3a85f35b583259cf5ca0344cd79c8899ba1bb7 Gitweb: https://git.kernel.org/tip/5c3a85f35b583259cf5ca0344cd79c889= 9ba1bb7 Author: Ard Biesheuvel AuthorDate: Tue, 22 Nov 2022 17:10:03 +01:00 Committer: Borislav Petkov CommitterDate: Tue, 22 Nov 2022 19:21:26 +01:00 x86/boot/compressed: Move bootargs parsing out of 32-bit startup code Move the logic that chooses between the different EFI entrypoints out of the 32-bit boot path, and into a 64-bit helper that can perform the same task much more cleanly. While at it, document the mixed mode boot flow in a code comment. Signed-off-by: Ard Biesheuvel Signed-off-by: Borislav Petkov Link: https://lore.kernel.org/r/20221122161017.2426828-4-ardb@kernel.org --- arch/x86/boot/compressed/efi_mixed.S | 43 +++++++++++++++++++++++++++- arch/x86/boot/compressed/head_64.S | 24 ++------------- 2 files changed, 47 insertions(+), 20 deletions(-) diff --git a/arch/x86/boot/compressed/efi_mixed.S b/arch/x86/boot/compresse= d/efi_mixed.S index 67e7edc..58ab2e1 100644 --- a/arch/x86/boot/compressed/efi_mixed.S +++ b/arch/x86/boot/compressed/efi_mixed.S @@ -22,6 +22,49 @@ =20 .code64 .text +/* + * When booting in 64-bit mode on 32-bit EFI firmware, startup_64_mixed_mo= de() + * is the first thing that runs after switching to long mode. Depending on + * whether the EFI handover protocol or the compat entry point was used to + * enter the kernel, it will either branch to the 64-bit EFI handover + * entrypoint at offset 0x390 in the image, or to the 64-bit EFI PE/COFF + * entrypoint efi_pe_entry(). In the former case, the bootloader must prov= ide a + * struct bootparams pointer as the third argument, so the presence of suc= h a + * pointer is used to disambiguate. + * + * +----------= ----+ + * +------------------+ +------------+ +------>| efi_pe_en= try | + * | efi32_pe_entry |---->| | | +----------= -+--+ + * +------------------+ | | +------+----------------+ = | + * | startup_32 |---->| startup_64_mixed_mode | = | + * +------------------+ | | +------+----------------+ = V + * | efi32_stub_entry |---->| | | +------------= ------+ + * +------------------+ +------------+ +---->| efi64_stub_= entry | + * +------------= -+----+ + * +------------+ +----------+ = | + * | startup_64 |<----| efi_main |<-------------= -+ + * +------------+ +----------+ + */ +SYM_FUNC_START(startup_64_mixed_mode) + lea efi32_boot_args(%rip), %rdx + mov 0(%rdx), %edi + mov 4(%rdx), %esi + mov 8(%rdx), %edx // saved bootparams pointer + test %edx, %edx + jnz efi64_stub_entry + /* + * efi_pe_entry uses MS calling convention, which requires 32 bytes of + * shadow space on the stack even if all arguments are passed in + * registers. We also need an additional 8 bytes for the space that + * would be occupied by the return address, and this also results in + * the correct stack alignment for entry. + */ + sub $40, %rsp + mov %rdi, %rcx // MS calling convention + mov %rsi, %rdx + jmp efi_pe_entry +SYM_FUNC_END(startup_64_mixed_mode) + SYM_FUNC_START(__efi64_thunk) push %rbp push %rbx diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/= head_64.S index 5d07ef7..f3d7de5 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -261,25 +261,9 @@ SYM_FUNC_START(startup_32) */ leal rva(startup_64)(%ebp), %eax #ifdef CONFIG_EFI_MIXED - movl rva(efi32_boot_args)(%ebp), %edi - testl %edi, %edi - jz 1f - leal rva(efi64_stub_entry)(%ebp), %eax - movl rva(efi32_boot_args+4)(%ebp), %esi - movl rva(efi32_boot_args+8)(%ebp), %edx // saved bootparams pointer - testl %edx, %edx - jnz 1f - /* - * efi_pe_entry uses MS calling convention, which requires 32 bytes of - * shadow space on the stack even if all arguments are passed in - * registers. We also need an additional 8 bytes for the space that - * would be occupied by the return address, and this also results in - * the correct stack alignment for entry. - */ - subl $40, %esp - leal rva(efi_pe_entry)(%ebp), %eax - movl %edi, %ecx // MS calling convention - movl %esi, %edx + cmpb $1, rva(efi_is64)(%ebp) + je 1f + leal rva(startup_64_mixed_mode)(%ebp), %eax 1: #endif /* Check if the C-bit position is correct when SEV is active */ @@ -779,7 +763,7 @@ SYM_DATA_END_LABEL(boot32_idt, SYM_L_GLOBAL, boot32_idt= _end) SYM_DATA(image_offset, .long 0) #endif #ifdef CONFIG_EFI_MIXED -SYM_DATA_LOCAL(efi32_boot_args, .long 0, 0, 0) +SYM_DATA(efi32_boot_args, .long 0, 0, 0) SYM_DATA(efi_is64, .byte 1) =20 #define ST32_boottime 60 // offsetof(efi_system_table_32_t, boottime)