From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751885AbdKVPd7 (ORCPT ); Wed, 22 Nov 2017 10:33:59 -0500 Received: from mx2.suse.de ([195.135.220.15]:52257 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751384AbdKVPd6 (ORCPT ); Wed, 22 Nov 2017 10:33:58 -0500 Date: Wed, 22 Nov 2017 16:33:38 +0100 From: Borislav Petkov To: Andy Lutomirski Cc: X86 ML , "linux-kernel@vger.kernel.org" , Brian Gerst , Dave Hansen , Linus Torvalds , Josh Poimboeuf Subject: Re: [PATCH v2 05/18] x86/fixmap: Generalize the GDT fixmap mechanism Message-ID: <20171122153327.fyxn4zspgdrjs45s@pd.tnic> References: <7d11626f17da123a741dc54b61edec5d868c3987.1511325444.git.luto@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <7d11626f17da123a741dc54b61edec5d868c3987.1511325444.git.luto@kernel.org> User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 21, 2017 at 08:44:00PM -0800, Andy Lutomirski wrote: > Currently, the GDT is an ad-hoc array of pages, one per CPU, in the > fixmap. Generalize it to be an array of a new struct cpu_entry_area > so that we can cleanly add new things to it. > > Signed-off-by: Andy Lutomirski > --- > arch/x86/include/asm/desc.h | 9 +-------- > arch/x86/include/asm/fixmap.h | 36 ++++++++++++++++++++++++++++++++++-- > arch/x86/kernel/cpu/common.c | 14 +++++++------- > arch/x86/xen/mmu_pv.c | 2 +- > 4 files changed, 43 insertions(+), 18 deletions(-) > > diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h > index 95cd95eb7285..194ffab00ebe 100644 > --- a/arch/x86/include/asm/desc.h > +++ b/arch/x86/include/asm/desc.h > @@ -60,17 +60,10 @@ static inline struct desc_struct *get_current_gdt_rw(void) > return this_cpu_ptr(&gdt_page)->gdt; > } > > -/* Get the fixmap index for a specific processor */ > -static inline unsigned int get_cpu_gdt_ro_index(int cpu) > -{ > - return FIX_GDT_REMAP_END - cpu; > -} > - > /* Provide the fixmap address of the remapped GDT */ > static inline struct desc_struct *get_cpu_gdt_ro(int cpu) > { > - unsigned int idx = get_cpu_gdt_ro_index(cpu); > - return (struct desc_struct *)__fix_to_virt(idx); > + return (struct desc_struct *)&get_cpu_entry_area(cpu)->gdt; > } > > /* Provide the current read-only GDT */ > diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h > index b0c505fe9a95..038b8474c7f8 100644 > --- a/arch/x86/include/asm/fixmap.h > +++ b/arch/x86/include/asm/fixmap.h Btw, the whole cpu_entry_area machinery looks like it should belong more in asm/processor.h and not in fixmap.h > @@ -44,6 +44,17 @@ extern unsigned long __FIXADDR_TOP; > PAGE_SIZE) > #endif > > +/* > + * cpu_entry_area is a percpu region in the fixmap that contains things > + * needed by the CPU and early entry/exit code. Real types aren't used > + * for all fields here to about circular header dependencies. s/about/avoid/ > + */ > +struct cpu_entry_area > +{ ERROR: open brace '{' following struct go on the same line #67: FILE: arch/x86/include/asm/fixmap.h:53: +struct cpu_entry_area +{ > + char gdt[PAGE_SIZE]; > +}; > + > +#define CPU_ENTRY_AREA_PAGES (sizeof(struct cpu_entry_area) / PAGE_SIZE) > > /* > * Here we define all the compile-time 'special' virtual > @@ -101,8 +112,8 @@ enum fixed_addresses { > FIX_LNW_VRTC, > #endif > /* Fixmap entries to remap the GDTs, one per processor. */ > - FIX_GDT_REMAP_BEGIN, > - FIX_GDT_REMAP_END = FIX_GDT_REMAP_BEGIN + NR_CPUS - 1, > + FIX_CPU_ENTRY_AREA_TOP, > + FIX_CPU_ENTRY_AREA_BOTTOM = FIX_CPU_ENTRY_AREA_TOP + (CPU_ENTRY_AREA_PAGES * NR_CPUS) - 1, > > #ifdef CONFIG_ACPI_APEI_GHES > /* Used for GHES mapping from assorted contexts */ > @@ -191,5 +202,26 @@ void __init *early_memremap_decrypted_wp(resource_size_t phys_addr, > void __early_set_fixmap(enum fixed_addresses idx, > phys_addr_t phys, pgprot_t flags); > > +static inline unsigned int __get_cpu_entry_area_page_index(int cpu, int page) > +{ > + BUILD_BUG_ON(sizeof(struct cpu_entry_area) % PAGE_SIZE != 0); BUILD_BUG_ON(sizeof(struct cpu_entry_area) % PAGE_SIZE); > + > + return FIX_CPU_ENTRY_AREA_BOTTOM - cpu*CPU_ENTRY_AREA_PAGES - page; > +} > + > +#define __get_cpu_entry_area_offset_index(cpu, offset) ({ \ > + BUILD_BUG_ON(offset % PAGE_SIZE != 0); \ BUILD_BUG_ON(offset % PAGE_SIZE); > + __get_cpu_entry_area_page_index(cpu, offset / PAGE_SIZE); \ > + }) > + > +#define get_cpu_entry_area_index(cpu, field) \ > + __get_cpu_entry_area_offset_index((cpu), offsetof(struct cpu_entry_area, field)) > + > +static inline struct cpu_entry_area *get_cpu_entry_area(int cpu) > +{ > + return (struct cpu_entry_area *) > + __fix_to_virt(__get_cpu_entry_area_page_index(cpu, 0)); Just let it stick out. -- Regards/Gruss, Boris. SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg) --