From patchwork Tue Feb 23 16:31:24 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Cooper X-Patchwork-Id: 8394321 Return-Path: X-Original-To: patchwork-xen-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id C07919FC55 for ; Tue, 23 Feb 2016 16:34:13 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id B942220328 for ; Tue, 23 Feb 2016 16:34:12 +0000 (UTC) Received: from lists.xen.org (lists.xenproject.org [50.57.142.19]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D47E22034C for ; Tue, 23 Feb 2016 16:34:10 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=lists.xen.org) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1aYFsM-0002JM-Nz; Tue, 23 Feb 2016 16:31:50 +0000 Received: from mail6.bemta5.messagelabs.com ([195.245.231.135]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1aYFsL-0002Ih-97 for xen-devel@lists.xen.org; Tue, 23 Feb 2016 16:31:49 +0000 Received: from [85.158.139.211] by server-6.bemta-5.messagelabs.com id 5B/59-03519-4798CC65; Tue, 23 Feb 2016 16:31:48 +0000 X-Env-Sender: prvs=8544ffb4f=Andrew.Cooper3@citrix.com X-Msg-Ref: server-13.tower-206.messagelabs.com!1456245104!24178922!3 X-Originating-IP: [66.165.176.63] X-SpamReason: No, hits=0.0 required=7.0 tests=sa_preprocessor: VHJ1c3RlZCBJUDogNjYuMTY1LjE3Ni42MyA9PiAzMDYwNDg=\n, received_headers: No Received headers X-StarScan-Received: X-StarScan-Version: 7.35.1; banners=-,-,- X-VirusChecked: Checked Received: (qmail 58913 invoked from network); 23 Feb 2016 16:31:47 -0000 Received: from smtp02.citrix.com (HELO SMTP02.CITRIX.COM) (66.165.176.63) by server-13.tower-206.messagelabs.com with RC4-SHA encrypted SMTP; 23 Feb 2016 16:31:47 -0000 X-IronPort-AV: E=Sophos;i="5.22,490,1449532800"; d="scan'208";a="340282616" From: Andrew Cooper To: Xen-devel Date: Tue, 23 Feb 2016 16:31:24 +0000 Message-ID: <1456245085-2302-8-git-send-email-andrew.cooper3@citrix.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1456245085-2302-1-git-send-email-andrew.cooper3@citrix.com> References: <1456245085-2302-1-git-send-email-andrew.cooper3@citrix.com> MIME-Version: 1.0 X-DLP: MIA2 Cc: Andrew Cooper , Jan Beulich Subject: [Xen-devel] [PATCH v2 7/8] xen/x86: Use 2M superpages for text/data/bss mappings X-BeenThere: xen-devel@lists.xen.org X-Mailman-Version: 2.1.13 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This balloons the size of Xen in memory from 4.4MB to 8MB, because of the required alignment adjustments. However * All mappings are 2M superpages. * .text (and .init at boot) are the only sections marked executable. * .text and .rodata are marked read-only. Signed-off-by: Andrew Cooper --- CC: Jan Beulich v2: * .data and .bss are adjcent (from earlier patch), so don't require 2M alignment --- xen/arch/x86/setup.c | 38 +++++++++++++++++++++++++++++++++++--- xen/arch/x86/xen.lds.S | 27 +++++++++++++++++++++++++++ xen/include/xen/kernel.h | 7 +++++++ 3 files changed, 69 insertions(+), 3 deletions(-) diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c index cddf954..806fa95 100644 --- a/xen/arch/x86/setup.c +++ b/xen/arch/x86/setup.c @@ -920,14 +920,46 @@ void __init noreturn __start_xen(unsigned long mbi_p) /* The only data mappings to be relocated are in the Xen area. */ pl2e = __va(__pa(l2_xenmap)); + /* + * Undo the temporary-hooking of the l1_identmap. __2M_text_start + * is contained in this PTE. + */ *pl2e++ = l2e_from_pfn(xen_phys_start >> PAGE_SHIFT, - PAGE_HYPERVISOR_RWX | _PAGE_PSE); + PAGE_HYPERVISOR_RX | _PAGE_PSE); for ( i = 1; i < L2_PAGETABLE_ENTRIES; i++, pl2e++ ) { + unsigned int flags; + if ( !(l2e_get_flags(*pl2e) & _PAGE_PRESENT) ) continue; - *pl2e = l2e_from_intpte(l2e_get_intpte(*pl2e) + - xen_phys_start); + + if ( i < l2_table_offset((unsigned long)&__2M_text_end) ) + { + flags = PAGE_HYPERVISOR_RX | _PAGE_PSE; + } + else if ( i >= l2_table_offset((unsigned long)&__2M_rodata_start) && + i < l2_table_offset((unsigned long)&__2M_rodata_end) ) + { + flags = PAGE_HYPERVISOR_RO | _PAGE_PSE; + } + else if ( i >= l2_table_offset((unsigned long)&__2M_init_start) && + i < l2_table_offset((unsigned long)&__2M_init_end) ) + { + flags = PAGE_HYPERVISOR_RWX | _PAGE_PSE; + } + else if ( (i >= l2_table_offset((unsigned long)&__2M_rwdata_start) && + i < l2_table_offset((unsigned long)&__2M_rwdata_end)) ) + { + flags = PAGE_HYPERVISOR_RW | _PAGE_PSE; + } + else + { + *pl2e = l2e_empty(); + continue; + } + + *pl2e = l2e_from_paddr( + l2e_get_paddr(*pl2e) + xen_phys_start, flags); } /* Re-sync the stack and then switch to relocated pagetables. */ diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S index 63dbcff..aadb082 100644 --- a/xen/arch/x86/xen.lds.S +++ b/xen/arch/x86/xen.lds.S @@ -38,6 +38,9 @@ SECTIONS . = __XEN_VIRT_START; __image_base__ = .; #endif + + __2M_text_start = .; /* Start of 2M superpages, mapped RX. */ + . = __XEN_VIRT_START + MB(1); _start = .; .text : { @@ -50,6 +53,10 @@ SECTIONS _etext = .; /* End of text section */ } :text = 0x9090 + . = ALIGN(MB(2)); + __2M_text_end = .; + + __2M_rodata_start = .; /* Start of 2M superpages, mapped RO. */ .rodata : { /* Bug frames table */ . = ALIGN(4); @@ -73,6 +80,10 @@ SECTIONS #endif } :text + . = ALIGN(MB(2)); + __2M_rodata_end = .; + + __2M_init_start = .; /* Start of 2M superpages, mapped RWX (boot only). */ . = ALIGN(PAGE_SIZE); /* Init code and data */ __init_begin = .; .init.text : { @@ -135,6 +146,10 @@ SECTIONS . = ALIGN(PAGE_SIZE); __init_end = .; + . = ALIGN(MB(2)); + __2M_init_end = .; + + __2M_rwdata_start = .; /* Start of 2M superpages, mapped RW. */ . = ALIGN(SMP_CACHE_BYTES); .data.read_mostly : { /* Exception table */ @@ -183,6 +198,9 @@ SECTIONS } :text _end = . ; + . = ALIGN(MB(2)); + __2M_rwdata_end = .; + #ifdef EFI . = ALIGN(4); .reloc : { @@ -229,4 +247,13 @@ ASSERT(__image_base__ > XEN_VIRT_START || ASSERT(kexec_reloc_size - kexec_reloc <= PAGE_SIZE, "kexec_reloc is too large") #endif +ASSERT(IS_ALIGNED(__2M_text_start, MB(2)), "__2M_text_start misaligned") +ASSERT(IS_ALIGNED(__2M_text_end, MB(2)), "__2M_text_end misaligned") +ASSERT(IS_ALIGNED(__2M_rodata_start, MB(2)), "__2M_rodata_start misaligned") +ASSERT(IS_ALIGNED(__2M_rodata_end, MB(2)), "__2M_rodata_end misaligned") +ASSERT(IS_ALIGNED(__2M_init_start, MB(2)), "__2M_init_start misaligned") +ASSERT(IS_ALIGNED(__2M_init_end, MB(2)), "__2M_init_end misaligned") +ASSERT(IS_ALIGNED(__2M_rwdata_start, MB(2)), "__2M_rwdata_start misaligned") +ASSERT(IS_ALIGNED(__2M_rwdata_end, MB(2)), "__2M_rwdata_end misaligned") + ASSERT(IS_ALIGNED(cpu0_stack, STACK_SIZE), "cpu0_stack misaligned") diff --git a/xen/include/xen/kernel.h b/xen/include/xen/kernel.h index 548b64d..8a48334 100644 --- a/xen/include/xen/kernel.h +++ b/xen/include/xen/kernel.h @@ -65,6 +65,13 @@ 1; \ }) +#ifdef CONFIG_X86 +extern const char __2M_text_start[], __2M_text_end[]; +extern const char __2M_rodata_start[], __2M_rodata_end[]; +extern char __2M_init_start[], __2M_init_end[]; +extern char __2M_rwdata_start[], __2M_rwdata_end[]; +#endif + extern char _start[], _end[], start[]; #define is_kernel(p) ({ \ char *__p = (char *)(unsigned long)(p); \