From patchwork Mon May 8 07:03:14 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 680353 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 44B3AC77B73 for ; Mon, 8 May 2023 07:04:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232845AbjEHHEE (ORCPT ); Mon, 8 May 2023 03:04:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45846 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232699AbjEHHEA (ORCPT ); Mon, 8 May 2023 03:04:00 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3A0061A115; Mon, 8 May 2023 00:03:58 -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 dfw.source.kernel.org (Postfix) with ESMTPS id B28AC61F8A; Mon, 8 May 2023 07:03:57 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 58D98C4339C; Mon, 8 May 2023 07:03:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1683529437; bh=rxt+/g9xwfTqH/LFwaurDzU1JjHkdOgxvezFD/2D/FU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JInth/2qmJqlZYbTRm+OBct7kDHZzhMMZq0zby9msXFOUslVWYir79Oc3cBP/fqIg tHjSM0kC7Mz5OG1RxNzmn+yZiHGLR+uiw2qD3S6U1uWBq6KArOt5IasImz+7fV520d Z6/SQkQ6BsxeNL3y//45UMZTTyEdo1k5XsBoq8h+hqjrKsm+g1wzkSzEzV0nVaA+bE snPZygFAomT3zFiJREgSYdjm6HEDTtgZt52/l88+sETD2p6DJhlx077XVG4uunPFEr N3WGWbJfucOexe8Al+0ojee7rGa/IY4aCAvl0oBzE8dPPSDCz9vgwUTacEaLu4NQVe Q4rraUhIj5meg== From: Ard Biesheuvel To: linux-efi@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Ard Biesheuvel , Evgeniy Baskov , Borislav Petkov , Andy Lutomirski , Dave Hansen , Ingo Molnar , Peter Zijlstra , Thomas Gleixner , Alexey Khoroshilov , Peter Jones , Gerd Hoffmann , Dave Young , Mario Limonciello , Kees Cook , Tom Lendacky , "Kirill A . Shutemov" , Linus Torvalds Subject: [PATCH v2 04/20] x86: decompressor: Use standard calling convention for trampoline Date: Mon, 8 May 2023 09:03:14 +0200 Message-Id: <20230508070330.582131-5-ardb@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230508070330.582131-1-ardb@kernel.org> References: <20230508070330.582131-1-ardb@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=4077; i=ardb@kernel.org; h=from:subject; bh=rxt+/g9xwfTqH/LFwaurDzU1JjHkdOgxvezFD/2D/FU=; b=owGbwMvMwCFmkMcZplerG8N4Wi2JISVi3rrId56lOhdm7XJ40vaGv11ZRUqVt7+iZc6EzVtX7 wk3XPKso5SFQYyDQVZMkUVg9t93O09PlKp1niULM4eVCWQIAxenAEzkw2ZGhtu9lQ3T7ZsZEqdG ciXOXKq4aY/LdpEln4WPXr+QcHynZRgjw7UFzb8EnYVnT5a9svr7/pnPPgibXt91IZDtsReX99x /m7gA X-Developer-Key: i=ardb@kernel.org; a=openpgp; fpr=F43D03328115A198C90016883D200E9CA6329909 Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org Update the trampoline code so its arguments are passed via RDI and RSI, which matches the ordinary SysV calling convention for x86_64. This will allow us to call this code directly from C. Signed-off-by: Ard Biesheuvel Acked-by: Kirill A. Shutemov --- arch/x86/boot/compressed/head_64.S | 30 +++++++++----------- arch/x86/boot/compressed/pgtable.h | 2 +- 2 files changed, 14 insertions(+), 18 deletions(-) diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index 81b53b576cdd05ae..b1f8a867777120bb 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -454,9 +454,9 @@ SYM_CODE_START(startup_64) movq %r15, %rdi /* pass struct boot_params pointer */ call paging_prepare - /* Save the trampoline address in RCX */ - movq %rax, %rcx - + /* Pass the trampoline address and boolean flag as args #1 and #2 */ + movq %rax, %rdi + movq %rdx, %rsi leaq TRAMPOLINE_32BIT_CODE_OFFSET(%rax), %rax call *%rax @@ -560,11 +560,11 @@ SYM_FUNC_END(.Lrelocated) /* * This is the 32-bit trampoline that will be copied over to low memory. * - * ECX contains the base address of the trampoline memory. - * Non zero RDX means trampoline needs to enable 5-level paging. + * EDI contains the base address of the trampoline memory. + * Non-zero ESI means trampoline needs to enable 5-level paging. */ SYM_CODE_START(trampoline_32bit_src) - popq %rdi + popq %r8 /* Switch to compatibility mode (CS.L = 0 CS.D = 1) via far return */ pushq $__KERNEL32_CS leaq 0f(%rip), %rax @@ -578,7 +578,7 @@ SYM_CODE_START(trampoline_32bit_src) movl %eax, %ss /* Set up new stack */ - leal TRAMPOLINE_32BIT_STACK_END(%ecx), %esp + leal TRAMPOLINE_32BIT_STACK_END(%edi), %esp /* Disable paging */ movl %cr0, %eax @@ -586,7 +586,7 @@ SYM_CODE_START(trampoline_32bit_src) movl %eax, %cr0 /* Check what paging mode we want to be in after the trampoline */ - testl %edx, %edx + testl %esi, %esi jz 1f /* We want 5-level paging: don't touch CR3 if it already points to 5-level page tables */ @@ -601,21 +601,17 @@ SYM_CODE_START(trampoline_32bit_src) jz 3f 2: /* Point CR3 to the trampoline's new top level page table */ - leal TRAMPOLINE_32BIT_PGTABLE_OFFSET(%ecx), %eax + leal TRAMPOLINE_32BIT_PGTABLE_OFFSET(%edi), %eax movl %eax, %cr3 3: /* Set EFER.LME=1 as a precaution in case hypervsior pulls the rug */ - pushl %ecx - pushl %edx movl $MSR_EFER, %ecx rdmsr btsl $_EFER_LME, %eax /* Avoid writing EFER if no change was made (for TDX guest) */ jc 1f wrmsr -1: popl %edx - popl %ecx - +1: #ifdef CONFIG_X86_MCE /* * Preserve CR4.MCE if the kernel will enable #MC support. @@ -632,14 +628,14 @@ SYM_CODE_START(trampoline_32bit_src) /* Enable PAE and LA57 (if required) paging modes */ orl $X86_CR4_PAE, %eax - testl %edx, %edx + testl %esi, %esi jz 1f orl $X86_CR4_LA57, %eax 1: movl %eax, %cr4 /* Calculate address of paging_enabled() once we are executing in the trampoline */ - leal .Lpaging_enabled - trampoline_32bit_src + TRAMPOLINE_32BIT_CODE_OFFSET(%ecx), %eax + leal .Lpaging_enabled - trampoline_32bit_src + TRAMPOLINE_32BIT_CODE_OFFSET(%edi), %eax /* Prepare the stack for far return to Long Mode */ pushl $__KERNEL_CS @@ -656,7 +652,7 @@ SYM_CODE_END(trampoline_32bit_src) .code64 SYM_FUNC_START_LOCAL_NOALIGN(.Lpaging_enabled) /* Return from the trampoline */ - jmp *%rdi + jmp *%r8 SYM_FUNC_END(.Lpaging_enabled) /* diff --git a/arch/x86/boot/compressed/pgtable.h b/arch/x86/boot/compressed/pgtable.h index 91dbb99203fbce2d..4e8cef135226bcbb 100644 --- a/arch/x86/boot/compressed/pgtable.h +++ b/arch/x86/boot/compressed/pgtable.h @@ -14,7 +14,7 @@ extern unsigned long *trampoline_32bit; -extern void trampoline_32bit_src(void *return_ptr); +extern void trampoline_32bit_src(void *trampoline, bool enable_5lvl); #endif /* __ASSEMBLER__ */ #endif /* BOOT_COMPRESSED_PAGETABLE_H */