From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1830FC282CB for ; Wed, 6 Feb 2019 00:11:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CD56F218C3 for ; Wed, 6 Feb 2019 00:11:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=arista.com header.i=@arista.com header.b="ErP5Hen9" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728970AbfBFALf (ORCPT ); Tue, 5 Feb 2019 19:11:35 -0500 Received: from mail-ed1-f67.google.com ([209.85.208.67]:36764 "EHLO mail-ed1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728703AbfBFALe (ORCPT ); Tue, 5 Feb 2019 19:11:34 -0500 Received: by mail-ed1-f67.google.com with SMTP id d12so3445294edy.3 for ; Tue, 05 Feb 2019 16:11:32 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arista.com; s=googlenew; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=a6FQqHa1rlbDWsBMTo823W1nruhzQX7vLOJJT+3cw68=; b=ErP5Hen9uv1OAdWFBTRyNOmk9xRjmo9xQwvJ6VKb1rRJgz1xwkeDS7MSLs+2fQKiVU pC4fn7aNJ8WBMCSuIO4jHHXHMmAGlSqtH5pK651kcyI1NQmaBSYcX7Pr/17f+vPfsxr6 Bf7bqULDg/nimG8jwpXkMnXFeykqbm08nbWEqCYUnEdkHcWqX1I9RgDC1ia+bIwwDMIB 5KU1rYOmz7zKWYmrw/Ug37+VZxMPDcUuf7Yyazro8IDD4YLAbSjbnvvTplRcGzzSOtOd 8j1EJChawpT0WulWgwZ6gFGAz5Zyl1fVjNNP3jRd5nYKdqR1EO+MTmCvz2oZSNtMwYz/ OTJQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=a6FQqHa1rlbDWsBMTo823W1nruhzQX7vLOJJT+3cw68=; b=eGU7xUAcBAi/EAVP7ipshxGkj054v7qpdVehPROrtsI778BsD937BoenqCci1V1VyI U3tHoO+a2bW559fsBjEhAs4OLUEIQMNbslQIsmxKICZ5Flmbx5EAJTQ6hX9MAUaD8H+j kI3Wa27lGRmzz8vaKeDxTcOYOytqkosHqkpTjlEJ0VZj9gs7X2qkQhk2luPprfslYBsn sAUuXdNXUyGMj2kTYVtmefk7ueVXj/TXlJMy1pUPN1beDqh+yh8eSCfz3Yq0gqgeDktz KyZy5LSOtZamghjvc/Jsb/8ZH7envSA0hq8RkCH1MjsHeGYI9KwN8vxslMPW7hotSV34 ly3w== X-Gm-Message-State: AHQUAuaiFu6LCXoaZcyRchVIiLUXjkhqN3Dl6OxR+bYHbU7I3iga8S8Y ZCm6NqXy+izGKXY6sdgNZt7x2qh8CKA= X-Google-Smtp-Source: AHgI3IZ1/ikPZs7NO6GoFnpodaqdvBVjS+afDXgEyQNQD+jMZgnndHBMpUEMX9ycnkjpEJrlxyOpyg== X-Received: by 2002:a50:8d8c:: with SMTP id r12mr5897141edh.105.1549411891262; Tue, 05 Feb 2019 16:11:31 -0800 (PST) Received: from Mindolluin.ire.aristanetworks.com ([217.173.96.166]) by smtp.gmail.com with ESMTPSA id p30sm5489594eda.68.2019.02.05.16.11.30 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Tue, 05 Feb 2019 16:11:30 -0800 (PST) From: Dmitry Safonov To: linux-kernel@vger.kernel.org Cc: Dmitry Safonov , Adrian Reber , Andrei Vagin , Andrei Vagin , Andy Lutomirski , Andy Tucker , Arnd Bergmann , Christian Brauner , Cyrill Gorcunov , Dmitry Safonov <0x7f454c46@gmail.com>, "Eric W. Biederman" , "H. Peter Anvin" , Ingo Molnar , Jeff Dike , Oleg Nesterov , Pavel Emelyanov , Shuah Khan , Thomas Gleixner , containers@lists.linux-foundation.org, criu@openvz.org, linux-api@vger.kernel.org, x86@kernel.org Subject: [PATCH 16/32] x86/vdso: Generate vdso{,32}-timens.lds Date: Wed, 6 Feb 2019 00:10:50 +0000 Message-Id: <20190206001107.16488-17-dima@arista.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190206001107.16488-1-dima@arista.com> References: <20190206001107.16488-1-dima@arista.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org As it has been discussed on timens RFC, adding a new conditional branch `if (inside_time_ns)` on VDSO for all processes is undesirable. It will add a penalty for everybody as branch predictor may mispredict the jump. Also there are instruction cache lines wasted on cmp/jmp. Those effects of introducing time namespace are very much unwanted having in mind how much work have been spent on micro-optimisation vdso code. Addressing those problems, there are two versions of VDSO's .so: for host tasks (without any penalty) and for processes inside of time namespace with clk_to_ns() that subtracts offsets from host's time. Unfortunately, to allow changing VDSO VMA on a running process, the entry points to VDSO should have the same offsets (addresses). That's needed as i.e. application that calls setns() may have already resolved VDSO symbols in GOT/PLT. Provide two linker scripts: - *-timens.lds for building VDSO for processes inside time namespace (it has bigger functions and needs to build firstly) - *.lds for host processes VDSO (it has smaller functions and entry addresses should be adjusted with the linker script magic to fit with entries from timens) Signed-off-by: Dmitry Safonov --- arch/x86/entry/vdso/.gitignore | 1 + arch/x86/entry/vdso/Makefile | 18 ++++++++++++++---- arch/x86/entry/vdso/vdso-timens.lds.S | 7 +++++++ arch/x86/entry/vdso/vdso32/.gitignore | 1 + arch/x86/entry/vdso/vdso32/vdso32-timens.lds.S | 8 ++++++++ 5 files changed, 31 insertions(+), 4 deletions(-) create mode 100644 arch/x86/entry/vdso/vdso-timens.lds.S create mode 100644 arch/x86/entry/vdso/vdso32/vdso32-timens.lds.S diff --git a/arch/x86/entry/vdso/.gitignore b/arch/x86/entry/vdso/.gitignore index 9ab4fa4c7e7b..aaddf8f2171c 100644 --- a/arch/x86/entry/vdso/.gitignore +++ b/arch/x86/entry/vdso/.gitignore @@ -1,4 +1,5 @@ vdso.lds +vdso-timens.lds vdsox32.lds vdso32-syscall-syms.lds vdso32-sysenter-syms.lds diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile index ccb572831ea1..4e1659619e7e 100644 --- a/arch/x86/entry/vdso/Makefile +++ b/arch/x86/entry/vdso/Makefile @@ -44,11 +44,14 @@ vobjs := $(foreach F,$(vobjs-y),$(obj)/$F) vobjs32 := $(foreach F,$(vobjs32-y),$(obj)/$F) vobjs-timens := $(foreach F,$(vobjs-timens-y),$(obj)/$F) vobjs32-timens := $(foreach F,$(vobjs32-timens-y),$(obj)/$F) +dep-vdso.lds-$(CONFIG_TIME_NS) += $(obj)/vdso-image-64-timens.c +dep-vdso32.lds-$(CONFIG_TIME_NS) += $(obj)/vdso-image-32-timens.c $(obj)/vdso.o: $(obj)/vdso.so targets += vdso.lds $(vobjs-y) $(vobjs-timens-y) vdso64.entries targets += vdso32/vdso32.lds $(vobjs32-y) $(vobjs32-timens-y) vdso32.entries +targets += vdso-timens.lds vdso32/vdso32-timens.lds # Build the vDSO image C files and link them in. vdso_img_objs := $(vdso_img-y:%=vdso-image-%.o) @@ -59,11 +62,13 @@ targets += $(vdso_img_cfiles) targets += $(vdso_img_sodbg) $(vdso_img-y:%=vdso%.so) CPPFLAGS_vdso.lds += -P -C +CPPFLAGS_vdso-timens.lds := $(CPPFLAGS_vdso.lds) VDSO_LDFLAGS_vdso.lds = -m elf_x86_64 -soname linux-vdso.so.1 --no-undefined \ -z max-page-size=4096 +VDSO_LDFLAGS_vdso-timens.lds := $(VDSO_LDFLAGS_vdso.lds) -$(obj)/vdso64-timens.so.dbg: $(obj)/vdso.lds $(vobjs-timens) FORCE +$(obj)/vdso64-timens.so.dbg: $(obj)/vdso-timens.lds $(vobjs-timens) FORCE $(call if_changed,vdso) $(obj)/vdso64.so.dbg: $(obj)/vdso.lds $(vobjs) FORCE @@ -79,6 +84,9 @@ quiet_cmd_vdso2c = VDSO2C $@ $(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso%.so $(obj)/vdso2c FORCE $(call if_changed,vdso2c) +$(obj)/vdso.lds: $(dep-vdso.lds-y) $(obj)/vdso2c FORCE +$(obj)/vdso32/vdso32.lds: $(dep-vdso32.lds-y) $(obj)/vdso2c FORCE + # # Don't omit frame pointers for ease of userspace debugging, but do # optimize sibling calls. @@ -142,8 +150,10 @@ $(obj)/%.so: $(obj)/%.so.dbg $(obj)/vdsox32.so.dbg: $(obj)/vdsox32.lds $(vobjx32s) FORCE $(call if_changed,vdso) -CPPFLAGS_vdso32.lds = $(CPPFLAGS_vdso.lds) -VDSO_LDFLAGS_vdso32.lds = -m elf_i386 -soname linux-gate.so.1 +CPPFLAGS_vdso32.lds := $(CPPFLAGS_vdso.lds) +CPPFLAGS_vdso32-timens.lds := $(CPPFLAGS_vdso32.lds) +VDSO_LDFLAGS_vdso32.lds := -m elf_i386 -soname linux-gate.so.1 +VDSO_LDFLAGS_vdso32-timens.lds := $(VDSO_LDFLAGS_vdso32.lds) KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS)) -DBUILD_VDSO $(obj)/vdso32.so.dbg: KBUILD_AFLAGS = $(KBUILD_AFLAGS_32) @@ -172,7 +182,7 @@ endif $(obj)/vdso32.so.dbg: KBUILD_CFLAGS = $(KBUILD_CFLAGS_32) $(obj)/vdso32-timens.so.dbg: KBUILD_CFLAGS = $(KBUILD_CFLAGS_32) -$(obj)/vdso32-timens.so.dbg: $(obj)/vdso32/vdso32.lds $(vobjs32-timens) FORCE +$(obj)/vdso32-timens.so.dbg: $(obj)/vdso32/vdso32-timens.lds $(vobjs32-timens) FORCE $(call if_changed,vdso) $(obj)/vdso32.so.dbg: $(obj)/vdso32/vdso32.lds $(vobjs32) FORCE diff --git a/arch/x86/entry/vdso/vdso-timens.lds.S b/arch/x86/entry/vdso/vdso-timens.lds.S new file mode 100644 index 000000000000..687aba3bc5f0 --- /dev/null +++ b/arch/x86/entry/vdso/vdso-timens.lds.S @@ -0,0 +1,7 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Linker script for 64-bit timens vDSO. + */ + +#define UNALIGNED_ENTRIES +#include "vdso.lds.S" diff --git a/arch/x86/entry/vdso/vdso32/.gitignore b/arch/x86/entry/vdso/vdso32/.gitignore index e45fba9d0ced..ce4afb6ffb62 100644 --- a/arch/x86/entry/vdso/vdso32/.gitignore +++ b/arch/x86/entry/vdso/vdso32/.gitignore @@ -1 +1,2 @@ vdso32.lds +vdso32-timens.lds diff --git a/arch/x86/entry/vdso/vdso32/vdso32-timens.lds.S b/arch/x86/entry/vdso/vdso32/vdso32-timens.lds.S new file mode 100644 index 000000000000..1a3b3b1f0517 --- /dev/null +++ b/arch/x86/entry/vdso/vdso32/vdso32-timens.lds.S @@ -0,0 +1,8 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Linker script for 32-bit timens vDSO. + */ + +#define UNALIGNED_ENTRIES + +#include "vdso32.lds.S" -- 2.20.1