From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755239Ab0H0SVb (ORCPT ); Fri, 27 Aug 2010 14:21:31 -0400 Received: from rcsinet10.oracle.com ([148.87.113.121]:50014 "EHLO rcsinet10.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755189Ab0H0SV2 (ORCPT >); Fri, 27 Aug 2010 14:21:28 -0400 From: Konrad Rzeszutek Wilk To: linux-kernel@vger.kernel.org Cc: Konrad Rzeszutek Wilk , Sam Ravnborg , "H. Peter Anvin" , Fujita Tomonori , Thomas Gleixner , Ingo Molnar Subject: [PATCH] x86: Adding comments about .iommu_table and its neighbors. Date: Fri, 27 Aug 2010 14:19:33 -0400 Message-Id: <1282933173-19960-1-git-send-email-konrad.wilk@oracle.com> X-Mailer: git-send-email 1.7.0.1 In-Reply-To: <20100827144039.GA7438@merkur.ravnborg.org> References: <20100827144039.GA7438@merkur.ravnborg.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Updating the linker section with comments about .iommu_table and some other ones that I know of. CC: Sam Ravnborg CC: H. Peter Anvin CC: Fujita Tomonori CC: Thomas Gleixner CC: Ingo Molnar Signed-off-by: Konrad Rzeszutek Wilk --- arch/x86/kernel/vmlinux.lds.S | 22 ++++++++++++++++++++++ 1 files changed, 22 insertions(+), 0 deletions(-) diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index b92e040..3f07c37 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -242,6 +242,12 @@ SECTIONS __x86_cpu_dev_end = .; } + /* + * start address and size of operations which during runtime + * can be patched with virtualization friendly instructions or + * baremetal native ones. Think page table operations. + * Details in paravirt_types.h + */ . = ALIGN(8); .parainstructions : AT(ADDR(.parainstructions) - LOAD_OFFSET) { __parainstructions = .; @@ -249,6 +255,11 @@ SECTIONS __parainstructions_end = .; } + /* + * struct alt_inst entries. From the header (alternative.h): + * "Alternative instructions for different CPU types or capabilities" + * Think locking instructions on spinlocks. + */ . = ALIGN(8); .altinstructions : AT(ADDR(.altinstructions) - LOAD_OFFSET) { __alt_instructions = .; @@ -256,10 +267,21 @@ SECTIONS __alt_instructions_end = .; } + /* + * And here are the replacement instructions. The linker sticks + * them as binary blobs. The .altinstructions has enough data to + * get the address and the length of them to patch the kernel safely. + */ .altinstr_replacement : AT(ADDR(.altinstr_replacement) - LOAD_OFFSET) { *(.altinstr_replacement) } + /* + * struct iommu_table_entry entries are injected in this section. + * It is an array of IOMMUs which during run time gets sorted depending + * on its dependency order. After rootfs_initcall is complete + * this section can be safely removed. + */ .iommu_table : AT(ADDR(.iommu_table) - LOAD_OFFSET) { __iommu_table = .; *(.iommu_table) -- 1.7.0.1