From patchwork Thu Feb 13 14:59:26 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 206584 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A7B3FC2BA83 for ; Thu, 13 Feb 2020 14:59:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7FEF224650 for ; Thu, 13 Feb 2020 14:59:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581605992; bh=dzXGEwPuXZ+ThiLE83ovGglZj5LrVvfa4e0a9juvxuU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=LLRNi68VG3XfbFaEd0SyM1H7FJGCaqheTfUbCfh0alIkQ//L/kW30/qsx+tvgrSdQ fOn1Gw2F9ypkcLidWtkPYLPDg1kEF3hldkrLKfcMVH+W635eeUUuYAbZv6St3p4Q7i RcvG16HFS9JSWCitMUzirSX4IiGA40U8VwUDynQY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727683AbgBMO7w (ORCPT ); Thu, 13 Feb 2020 09:59:52 -0500 Received: from mail.kernel.org ([198.145.29.99]:41354 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726968AbgBMO7w (ORCPT ); Thu, 13 Feb 2020 09:59:52 -0500 Received: from cam-smtp0.cambridge.arm.com (fw-tnat.cambridge.arm.com [217.140.96.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 96EF3218AC; Thu, 13 Feb 2020 14:59:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581605990; bh=dzXGEwPuXZ+ThiLE83ovGglZj5LrVvfa4e0a9juvxuU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wtHnBCqALVbLhbo8hURER56BK+MTrVKkiDo3sAmQyWwtVEJUfFeLWNd3DfzUChHJj 1a86/2gx5cxXcZly4NqcuM1CuZ0BxDerG5+fiLyaKNQWVu2ANeSFLHBYU3f8AeyIJI ODQB3FiQakHD+n7/ZrMPEzbyZjygZ1UcscBEcNsQ= From: Ard Biesheuvel To: linux-efi@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org, Ard Biesheuvel , lersek@redhat.com, leif@nuviainc.com, pjones@redhat.com, mjg59@google.com, agraf@csgraf.de, daniel.kiper@oracle.com, hdegoede@redhat.com, nivedita@alum.mit.edu, mbrown@fensystems.co.uk, mingo@kernel.org Subject: [RFC PATCH 1/3] efi/x86: drop redundant .bss section Date: Thu, 13 Feb 2020 15:59:26 +0100 Message-Id: <20200213145928.7047-2-ardb@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200213145928.7047-1-ardb@kernel.org> References: <20200213145928.7047-1-ardb@kernel.org> Sender: linux-efi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org In commit c7fb93ec51d462ec ("x86/efi: Include a .bss section within the PE/COFF headers"), we added a separate .bss section to the PE/COFF header of the compressed kernel describing the static memory footprint of the decompressor, to ensure that it has enough headroom to decompress itself. We can achieve the exact same result by increasing the virtual size of the .text section, without changing the raw size, which, as per the PE/COFF specification, requires the loader to zero initialize the delta. Doing so frees up a slot in the section table, which we will use later to describe the mixed mode entrypoint. Signed-off-by: Ard Biesheuvel --- arch/x86/boot/header.S | 21 +----------- arch/x86/boot/tools/build.c | 35 ++++++++------------ 2 files changed, 14 insertions(+), 42 deletions(-) diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S index 97d9b6d6c1af..d59f6604bb42 100644 --- a/arch/x86/boot/header.S +++ b/arch/x86/boot/header.S @@ -106,7 +106,7 @@ coff_header: #else .word 0x8664 # x86-64 #endif - .word 4 # nr_sections + .word 3 # nr_sections .long 0 # TimeDateStamp .long 0 # PointerToSymbolTable .long 1 # NumberOfSymbols @@ -248,25 +248,6 @@ section_table: .word 0 # NumberOfLineNumbers .long 0x60500020 # Characteristics (section flags) - # - # The offset & size fields are filled in by build.c. - # - .ascii ".bss" - .byte 0 - .byte 0 - .byte 0 - .byte 0 - .long 0 - .long 0x0 - .long 0 # Size of initialized data - # on disk - .long 0x0 - .long 0 # PointerToRelocations - .long 0 # PointerToLineNumbers - .word 0 # NumberOfRelocations - .word 0 # NumberOfLineNumbers - .long 0xc8000080 # Characteristics (section flags) - #endif /* CONFIG_EFI_STUB */ # Kernel attributes; used by setup. This is part 1 of the diff --git a/arch/x86/boot/tools/build.c b/arch/x86/boot/tools/build.c index 55e669d29e54..0c8c5a52f1f0 100644 --- a/arch/x86/boot/tools/build.c +++ b/arch/x86/boot/tools/build.c @@ -203,10 +203,12 @@ static void update_pecoff_setup_and_reloc(unsigned int size) put_unaligned_le32(10, &buf[reloc_offset + 4]); } -static void update_pecoff_text(unsigned int text_start, unsigned int file_sz) +static void update_pecoff_text(unsigned int text_start, unsigned int file_sz, + unsigned int init_sz) { unsigned int pe_header; unsigned int text_sz = file_sz - text_start; + unsigned int bss_sz = init_sz - file_sz; pe_header = get_unaligned_le32(&buf[0x3c]); @@ -216,28 +218,19 @@ static void update_pecoff_text(unsigned int text_start, unsigned int file_sz) */ put_unaligned_le32(file_sz - 512, &buf[pe_header + 0x1c]); - /* - * Address of entry point for PE/COFF executable - */ - put_unaligned_le32(text_start + efi_pe_entry, &buf[pe_header + 0x28]); - - update_pecoff_section_header(".text", text_start, text_sz); -} - -static void update_pecoff_bss(unsigned int file_sz, unsigned int init_sz) -{ - unsigned int pe_header; - unsigned int bss_sz = init_sz - file_sz; - - pe_header = get_unaligned_le32(&buf[0x3c]); - /* Size of uninitialized data */ put_unaligned_le32(bss_sz, &buf[pe_header + 0x24]); /* Size of image */ put_unaligned_le32(init_sz, &buf[pe_header + 0x50]); - update_pecoff_section_header_fields(".bss", file_sz, bss_sz, 0, 0); + /* + * Address of entry point for PE/COFF executable + */ + put_unaligned_le32(text_start + efi_pe_entry, &buf[pe_header + 0x28]); + + update_pecoff_section_header_fields(".text", text_start, text_sz + bss_sz, + text_sz, text_start); } static int reserve_pecoff_reloc_section(int c) @@ -278,9 +271,8 @@ static void efi_stub_entry_update(void) static inline void update_pecoff_setup_and_reloc(unsigned int size) {} static inline void update_pecoff_text(unsigned int text_start, - unsigned int file_sz) {} -static inline void update_pecoff_bss(unsigned int file_sz, - unsigned int init_sz) {} + unsigned int file_sz, + unsigned int init_sz) {} static inline void efi_stub_defaults(void) {} static inline void efi_stub_entry_update(void) {} @@ -406,9 +398,8 @@ int main(int argc, char ** argv) buf[0x1f1] = setup_sectors-1; put_unaligned_le32(sys_size, &buf[0x1f4]); - update_pecoff_text(setup_sectors * 512, i + (sys_size * 16)); init_sz = get_unaligned_le32(&buf[0x260]); - update_pecoff_bss(i + (sys_size * 16), init_sz); + update_pecoff_text(setup_sectors * 512, i + (sys_size * 16), init_sz); efi_stub_entry_update(); From patchwork Thu Feb 13 14:59:28 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 206583 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3A84CC2BA83 for ; Thu, 13 Feb 2020 15:00:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0EDEC2073C for ; Thu, 13 Feb 2020 15:00:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581606000; bh=DOTtRdFIB/hKfBqsFmk6QEVi/+0venotMXHhie8bOHg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=uasTtpNFrsIIKNdZDHptKJJr4kkPN5VB6Daum0A+01cEt0zkuRC/Go2pW1OrXThhh Wvv3wg/lrt0DM886SHSs/hVU48ynHclqK++dRINJ2e5U6Vk1vyYVLIvFOVeIi9yDAs 153QEQCyRMq0y1CcSUzngrdbWhLN61y/i1P/9z7g= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727686AbgBMO77 (ORCPT ); Thu, 13 Feb 2020 09:59:59 -0500 Received: from mail.kernel.org ([198.145.29.99]:41714 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727685AbgBMO77 (ORCPT ); Thu, 13 Feb 2020 09:59:59 -0500 Received: from cam-smtp0.cambridge.arm.com (fw-tnat.cambridge.arm.com [217.140.96.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C8A2724649; Thu, 13 Feb 2020 14:59:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581605998; bh=DOTtRdFIB/hKfBqsFmk6QEVi/+0venotMXHhie8bOHg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1CK2t9slELuYxzfifGliWa30UPhanY+znLU/D2XckDAK1e1oyfSDsgf4Mf0p/lUd6 80wr7d4KiG8o3Pd6637iUOAXZKTKmuUTRUjNTZaXQ+pOWqR5HMo+bq0UZKNZXrm/pK NpjjgA4B3yTRgKuskKiUUujDoE5rJCBctr2dlCCA= From: Ard Biesheuvel To: linux-efi@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org, Ard Biesheuvel , lersek@redhat.com, leif@nuviainc.com, pjones@redhat.com, mjg59@google.com, agraf@csgraf.de, daniel.kiper@oracle.com, hdegoede@redhat.com, nivedita@alum.mit.edu, mbrown@fensystems.co.uk, mingo@kernel.org Subject: [RFC PATCH 3/3] efi/x86: implement mixed mode boot without the handover protocol Date: Thu, 13 Feb 2020 15:59:28 +0100 Message-Id: <20200213145928.7047-4-ardb@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200213145928.7047-1-ardb@kernel.org> References: <20200213145928.7047-1-ardb@kernel.org> Sender: linux-efi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org Add support for booting 64-bit x86 kernels from 32-bit firmware running on 64-bit capable CPUs without requiring the bootloader to implement the EFI handover protocol, allocate the setup block etc etc, all of which can be done by the stub using code we have already implemented. Instead, create an ordinary EFI application entrypoint but implemented in 32-bit code, so that it can be invoked by 32-bit firmware, and stash the address of this 32-bit entrypoint in the .compat section where the bootloader can find it. Note that we use the setup block embedded in the binary to go through startup_32(), but it gets reallocated and copied in efi_pe_entry(), using the same code that runs when the x86 kernel is booted in EFI mode from native firmware. This requires the loaded image protocol to be installed on the kernel image's EFI handle, and point to the kernel image itself and not to its loader. This, in turn, requires the bootloader to use the LoadImage() boot services to load the 64-bit image from 32-bit firmware, which is in fact supported by firmware based on EDK2. (Only StartImage() will fail, and instead, the newly added entrypoint needs to be invoked) Signed-off-by: Ard Biesheuvel --- arch/x86/boot/compressed/head_64.S | 61 +++++++++++++++++++- 1 file changed, 59 insertions(+), 2 deletions(-) diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index a4f5561c1c0e..7baaf9c97f5a 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -207,8 +207,8 @@ SYM_FUNC_START(startup_32) cmp $0, %edi jz 1f leal efi64_stub_entry(%ebp), %eax - movl %esi, %edx movl efi32_boot_args+4(%ebp), %esi + movl efi32_boot_args+8(%ebp), %edx // saved bootparams pointer 1: #endif pushl %eax @@ -233,6 +233,8 @@ SYM_FUNC_START(efi32_stub_entry) 1: pop %ebp subl $1b, %ebp + movl %esi, efi32_boot_args+8(%ebp) +2: movl %ecx, efi32_boot_args(%ebp) movl %edx, efi32_boot_args+4(%ebp) movb $0, efi_is64(%ebp) @@ -249,6 +251,49 @@ SYM_FUNC_START(efi32_stub_entry) jmp startup_32 SYM_FUNC_END(efi32_stub_entry) + +#define ST32_boottime 60 // offsetof(efi_system_table_32_t, boottime) +#define BS32_handle_protocol 88 // offsetof(efi_boot_services_32_t, handle_protocol) +#define LI32_image_base 32 // offsetof(efi_loaded_image_32_t, image_base) + + .subsection 1 + .code32 +SYM_FUNC_START(efi32_pe_entry) + pushl %ebp + + call 3f +3: pop %ebp + subl $3b, %ebp + + /* Get the loaded image protocol pointer from the image handle */ + subl $12, %esp // space for the loaded image pointer + pushl %esp // pass its address + leal 5f(%ebp), %eax + pushl %eax // pass the GUID address + pushl 28(%esp) // pass the image handle + + movl 36(%esp), %eax // sys_table + movl ST32_boottime(%eax), %eax // sys_table->boottime + call *BS32_handle_protocol(%eax) // sys_table->boottime->handle_protocol + cmp $0, %eax + jnz 4f + + movl 32(%esp), %ecx // image_handle + movl 36(%esp), %edx // sys_table + movl 12(%esp), %esi // loaded_image + movl LI32_image_base(%esi), %esi // loaded_image->image_base + jmp 2b + +4: addl $24, %esp + popl %ebp + ret +SYM_FUNC_END(efi32_pe_entry) + + /* EFI loaded image protocol GUID */ +5: .long 0x5B1B31A1 + .word 0x9562, 0x11d2 + .byte 0x8E, 0x3F, 0x00, 0xA0, 0xC9, 0x69, 0x72, 0x3B + .previous #endif .code64 @@ -465,11 +510,23 @@ SYM_CODE_END(startup_64) SYM_FUNC_START(efi64_stub_entry) SYM_FUNC_START_ALIAS(efi_stub_entry) and $~0xf, %rsp /* realign the stack */ +#ifdef CONFIG_EFI_MIXED + cmpl $0, %edx + jz 0f +#endif call efi_main movq %rax,%rsi movl BP_code32_start(%esi), %eax leaq startup_64(%rax), %rax jmp *%rax + +#ifdef CONFIG_EFI_MIXED +0: movl %edi, %ecx // MS calling convention + movl %esi, %edx + call efi_pe_entry +1: hlt + jmp 1b +#endif SYM_FUNC_END(efi64_stub_entry) SYM_FUNC_END_ALIAS(efi_stub_entry) #endif @@ -641,7 +698,7 @@ SYM_DATA_START_LOCAL(gdt) SYM_DATA_END_LABEL(gdt, SYM_L_LOCAL, gdt_end) #ifdef CONFIG_EFI_MIXED -SYM_DATA_LOCAL(efi32_boot_args, .long 0, 0) +SYM_DATA_LOCAL(efi32_boot_args, .long 0, 0, 0) SYM_DATA(efi_is64, .byte 1) #endif