From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756362Ab2LMWGk (ORCPT ); Thu, 13 Dec 2012 17:06:40 -0500 Received: from aserp1040.oracle.com ([141.146.126.69]:26694 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756460Ab2LMWCy (ORCPT ); Thu, 13 Dec 2012 17:02:54 -0500 From: Yinghai Lu To: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" Cc: "Eric W. Biederman" , Andrew Morton , linux-kernel@vger.kernel.org, Yinghai Lu Subject: [PATCH v6 19/27] x86, boot: update comments about entries for 64bit image Date: Thu, 13 Dec 2012 14:02:13 -0800 Message-Id: <1355436141-8668-20-git-send-email-yinghai@kernel.org> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1355436141-8668-1-git-send-email-yinghai@kernel.org> References: <1355436141-8668-1-git-send-email-yinghai@kernel.org> X-Source-IP: ucsinet21.oracle.com [156.151.31.93] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Now 64bit entry is fixed on 0x200, can not be changed anymore. Update the comments to reflect that. Signed-off-by: Yinghai Lu --- arch/x86/boot/compressed/head_64.S | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-) diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index 5c80b94..5ba0c95 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -37,6 +37,12 @@ __HEAD .code32 ENTRY(startup_32) + /* + * 32bit entry is 0, could not be changed! + * If we come here directly from a bootloader, + * kernel(text+data+bss+brk) ramdisk, zero_page, command line + * all need to be under 4G limit. + */ cld /* * Test KEEP_SEGMENTS flag to see if the bootloader is asking @@ -182,20 +188,18 @@ ENTRY(startup_32) lret ENDPROC(startup_32) - /* - * Be careful here startup_64 needs to be at a predictable - * address so I can export it in an ELF header. Bootloaders - * should look at the ELF header to find this address, as - * it may change in the future. - */ .code64 .org 0x200 ENTRY(startup_64) /* + * 64bit entry is 0x200, could not be changed! * We come here either from startup_32 or directly from a - * 64bit bootloader. If we come here from a bootloader we depend on - * an identity mapped page table being provied that maps our - * entire text+data+bss and hopefully all of memory. + * 64bit bootloader. + * If we come here from a bootloader, kernel(text+data+bss+brk), + * ramdisk, zero_page, command line could be above 4G. + * We depend on an identity mapped page table being provided + * that maps our entire kernel(text+data+bss+brk), and hopefully + * all of memory. */ #ifdef CONFIG_EFI_STUB /* -- 1.7.10.4