From patchwork Tue Apr 28 22:14:15 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nathan Chancellor X-Patchwork-Id: 11515737 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 351EB92C for ; Tue, 28 Apr 2020 22:14:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1D65020731 for ; Tue, 28 Apr 2020 22:14:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="BdArs0mr" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726842AbgD1WOn (ORCPT ); Tue, 28 Apr 2020 18:14:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50682 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726256AbgD1WOm (ORCPT ); Tue, 28 Apr 2020 18:14:42 -0400 Received: from mail-oi1-x244.google.com (mail-oi1-x244.google.com [IPv6:2607:f8b0:4864:20::244]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 359BBC03C1AC; Tue, 28 Apr 2020 15:14:42 -0700 (PDT) Received: by mail-oi1-x244.google.com with SMTP id x10so4614652oie.1; Tue, 28 Apr 2020 15:14:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=7XOJVk+5A6GR6NFBTWs7oO+THtl1yOH5oBnsh7etyh4=; b=BdArs0mrOvf4vDg6yt3ztcZ29g5JtSe1yTHw1ft5HjnH3G62okZZMu63TXKmhYKlxg 4sUvq3tM0F6IEdnnanK+kwRi3j+q8W9XmHazDT0uZj7NJRTpkKPklnt3Fr2BQJlCcrIG bx1wLEEJvABjRPJlcIPUpvm3dgwk50IUI/ianTZg1InMCgk7T4DLWaUhOTiv7Hlg+del IMY4HBW31mSvSDDTrGrlEuBHqhaCaDSdk/ntrlai5d0roNS857bf6xlBSO2B4EBHQG5C t60jShHdyYU5GRWGrAl5NKrlYGvkvNA0DYS9CEb6IqL+jhFJEnsArQJvnWGXln1OAIqw 3gBw== 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=7XOJVk+5A6GR6NFBTWs7oO+THtl1yOH5oBnsh7etyh4=; b=Akm1gqw6+KBGHqQUrh3X5ZlM2601cs3qRjyczsaTJKF9oN6Rt9DJeL25nHEID/sopn jgq1OgOZj1v+8oeaHUc7JfN+Wn3KpGjmw2lws4ibrP9zeqtHdCaqfxqMhLJxuNQ1Xilf mvLnWWzlkJcNP6sdlM0El+vLtOHbeYX3lfy9ixSji1HaA5YfR4MAqBu8kXftaT6bWXG6 a5WRN2yBQtDjkEg72a0pFXEJufnzJ74p9OlJIzOvfwS80tYKZX+8M3qp79ppQxw+bbdB RzfuzbiXPAMRuDQL9uUN4qsC+OpC3pE411M69ClH3bQaTeeosygp7/AV2ypqu8/c4cWm 0oZg== X-Gm-Message-State: AGi0PuaNsZTqJZLGDVYFj/UWaYtYs9N21da8MIEYpQkZNfRHLFSlH21f MfJeH2yV69jFjG86Bixenr0= X-Google-Smtp-Source: APiQypJdXXmuvEQupoPz94R0JkmRbpfP1GKLTTIk9oabIbN6Ux7EMlPAJppliNPI6I6KSjObc+nMLg== X-Received: by 2002:aca:d06:: with SMTP id 6mr4352574oin.78.1588112081485; Tue, 28 Apr 2020 15:14:41 -0700 (PDT) Received: from localhost.localdomain ([2604:1380:4111:8b00::1]) by smtp.gmail.com with ESMTPSA id 186sm5267476ooi.30.2020.04.28.15.14.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 28 Apr 2020 15:14:40 -0700 (PDT) From: Nathan Chancellor To: Thomas Bogendoerfer , Masahiro Yamada Cc: linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, linux-kbuild@vger.kernel.org, Nick Desaulniers , Fangrui Song , Sami Tolvanen , Dmitry Golovin , Sedat Dilek , Nathan Chancellor Subject: [PATCH v4 1/5] kbuild: add CONFIG_LD_IS_LLD Date: Tue, 28 Apr 2020 15:14:15 -0700 Message-Id: <20200428221419.2530697-2-natechancellor@gmail.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200428221419.2530697-1-natechancellor@gmail.com> References: <20200423171807.29713-1-natechancellor@gmail.com> <20200428221419.2530697-1-natechancellor@gmail.com> MIME-Version: 1.0 X-Patchwork-Bot: notify Sender: linux-kbuild-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org From: Sami Tolvanen Similarly to the CC_IS_CLANG config, add LD_IS_LLD to avoid GNU ld specific logic such as ld-version or ld-ifversion and gain the ability to select potential features that depend on the linker at configuration time such as LTO. Signed-off-by: Sami Tolvanen Acked-by: Masahiro Yamada [nc: Reword commit message] Signed-off-by: Nathan Chancellor Tested-by: Sedat Dilek Reviewed-by: Sedat Dilek --- v3 -> v4: * No changes. v2 -> v3: * Add Masahiro's ack. v1 -> v2: * No changes. Sami, please scream if you are unhappy with how I worded this commit. init/Kconfig | 3 +++ 1 file changed, 3 insertions(+) base-commit: 96c9a7802af7d500a582d89a8b864584fe878c1b diff --git a/init/Kconfig b/init/Kconfig index 9e22ee8fbd75e..c15ee42b82726 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -23,6 +23,9 @@ config LD_VERSION config CC_IS_CLANG def_bool $(success,$(CC) --version | head -n 1 | grep -q clang) +config LD_IS_LLD + def_bool $(success,$(LD) -v | head -n 1 | grep -q LLD) + config CLANG_VERSION int default $(shell,$(srctree)/scripts/clang-version.sh $(CC)) From patchwork Tue Apr 28 22:14:16 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nathan Chancellor X-Patchwork-Id: 11515735 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id AC58215AB for ; Tue, 28 Apr 2020 22:14:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8EF362076A for ; Tue, 28 Apr 2020 22:14:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="l27izJS8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726256AbgD1WOo (ORCPT ); Tue, 28 Apr 2020 18:14:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50684 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726884AbgD1WOn (ORCPT ); Tue, 28 Apr 2020 18:14:43 -0400 Received: from mail-oi1-x244.google.com (mail-oi1-x244.google.com [IPv6:2607:f8b0:4864:20::244]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 336C8C03C1AC; Tue, 28 Apr 2020 15:14:43 -0700 (PDT) Received: by mail-oi1-x244.google.com with SMTP id a2so4549747oia.11; Tue, 28 Apr 2020 15:14:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=zb1r7udqkPpghcAA099YBR0r79TnU7CL/+l6zX2FrtY=; b=l27izJS8OBRWIRDCtgzoOfsf44WXDIr+bbAE+m2Td4/0V1MoS1gixfeA8Oh99cr5Y3 x8CPHcfkAzXrpZAfBFS5heTG3I0/YvVpnR06h6RHzS+yT4gDAs5DTtSar1MJ7MMjoDxT zNLVsZ7FeQnjNQ1tYSg5H+UdmUSVKGmvfaocdilZjwuZv+dLBZUjZvbQoWOYySbBzI16 0LHLiZmT7pA5PyT592U63KzACQAyo32kPUJzxPMFhMZvHI1JbNFn9f+rlbN2qGJoDF21 zZ0y8Ajr2+hxJj7st2x+WQtcKqcUQC4RwYBtJc5HXWQbMx/ac2qwDIR4mvoAoC2idmfZ KSww== 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=zb1r7udqkPpghcAA099YBR0r79TnU7CL/+l6zX2FrtY=; b=RjXZjK4UHJRsgqDYs8RCYu3n2d9SvBtPX3iZxgPS9dS/3RVbuIUESVb6qMmZEr/iis d71Y4Wb1xi5ZapQrVTqPFsByX2eWXcoBUv8Jvw3Bbi4yhFMdU4IRy/aDyR7nQ3HHtQAx OdkS+ZntNes9yrzo4zn92H+mMndT4S5LZpClJ5MfowFfzIWmI75kw2Buxo+YN3VILcgo hknHYn9xSMDZ0Naw9QJGsonaacZakLKRX0wtu0fZsUqVBlCYXwLMENA015CR3BtGSxjk E5dmhz5hzf6uU0bkg2k1rKVCCoM7FvKJwUGSYWSIIIlzYpoznHOpsFYb+XXgULvZvZAP srEQ== X-Gm-Message-State: AGi0PuYHJ2bwBJByvBbdXo75A7YIMzx1Dsu3yj1HfzCkd8rGY+DGfA/i sc6L13mer9vpwQasyw+w6ml2tQCEb7s= X-Google-Smtp-Source: APiQypIX6wAdCIUfNT1DTBfD1vHWMIOvDzIFzcWFGd4o0rt0yf0/tRDn8udG2XDVwZ2ByYagld2Vbw== X-Received: by 2002:aca:5e41:: with SMTP id s62mr4503048oib.53.1588112082531; Tue, 28 Apr 2020 15:14:42 -0700 (PDT) Received: from localhost.localdomain ([2604:1380:4111:8b00::1]) by smtp.gmail.com with ESMTPSA id 186sm5267476ooi.30.2020.04.28.15.14.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 28 Apr 2020 15:14:41 -0700 (PDT) From: Nathan Chancellor To: Thomas Bogendoerfer , Masahiro Yamada Cc: linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, linux-kbuild@vger.kernel.org, Nick Desaulniers , Fangrui Song , Sami Tolvanen , Dmitry Golovin , Sedat Dilek , Nathan Chancellor Subject: [PATCH v4 2/5] MIPS: VDSO: Move disabling the VDSO logic to Kconfig Date: Tue, 28 Apr 2020 15:14:16 -0700 Message-Id: <20200428221419.2530697-3-natechancellor@gmail.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200428221419.2530697-1-natechancellor@gmail.com> References: <20200423171807.29713-1-natechancellor@gmail.com> <20200428221419.2530697-1-natechancellor@gmail.com> MIME-Version: 1.0 X-Patchwork-Bot: notify Sender: linux-kbuild-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org After commit 9553d16fa671 ("init/kconfig: Add LD_VERSION Kconfig"), we have access to GNU ld's version at configuration time. As a result, we can make it clearer under what configuration circumstances the MIPS VDSO needs to be disabled. This is a prerequisite for getting rid of the MIPS VDSO binutils warning and linking the VDSO when LD is ld.lld. Wrapping the call to ld-ifversion with CONFIG_LD_IS_LLD does not work because the config values are wiped away during 'make clean'. Signed-off-by: Nathan Chancellor --- v3 -> v4: * No changes. v2 -> v3: * Fix CONFIG macro in arch/mips/vdso/vdso.lds.S, thanks to Sedat for catching it. v1 -> v2: * New patch. arch/mips/Kconfig | 2 ++ arch/mips/vdso/Kconfig | 18 ++++++++++++++++++ arch/mips/vdso/Makefile | 30 ++---------------------------- arch/mips/vdso/vdso.lds.S | 2 +- 4 files changed, 23 insertions(+), 29 deletions(-) create mode 100644 arch/mips/vdso/Kconfig diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index 690718b3701af..45220e4b8a653 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -3275,3 +3275,5 @@ endmenu source "drivers/firmware/Kconfig" source "arch/mips/kvm/Kconfig" + +source "arch/mips/vdso/Kconfig" diff --git a/arch/mips/vdso/Kconfig b/arch/mips/vdso/Kconfig new file mode 100644 index 0000000000000..36a52158d849b --- /dev/null +++ b/arch/mips/vdso/Kconfig @@ -0,0 +1,18 @@ +# For the pre-R6 code in arch/mips/vdso/vdso.h for locating +# the base address of VDSO, the linker will emit a R_MIPS_PC32 +# relocation in binutils > 2.25 but it will fail with older versions +# because that relocation is not supported for that symbol. As a result +# of which we are forced to disable the VDSO symbols when building +# with < 2.25 binutils on pre-R6 kernels. For more references on why we +# can't use other methods to get the base address of VDSO please refer to +# the comments on that file. +# +# GCC (at least up to version 9.2) appears to emit function calls that make use +# of the GOT when targeting microMIPS, which we can't use in the VDSO due to +# the lack of relocations. As such, we disable the VDSO for microMIPS builds. + +config MIPS_LD_CAN_LINK_VDSO + def_bool LD_VERSION >= 225000000 + +config MIPS_DISABLE_VDSO + def_bool CPU_MICROMIPS || (!CPU_MIPSR6 && !MIPS_LD_CAN_LINK_VDSO) diff --git a/arch/mips/vdso/Makefile b/arch/mips/vdso/Makefile index d7fe8408603e8..92b53d1df42c3 100644 --- a/arch/mips/vdso/Makefile +++ b/arch/mips/vdso/Makefile @@ -52,37 +52,11 @@ endif CFLAGS_REMOVE_vgettimeofday.o = -pg -DISABLE_VDSO := n - -# -# For the pre-R6 code in arch/mips/vdso/vdso.h for locating -# the base address of VDSO, the linker will emit a R_MIPS_PC32 -# relocation in binutils > 2.25 but it will fail with older versions -# because that relocation is not supported for that symbol. As a result -# of which we are forced to disable the VDSO symbols when building -# with < 2.25 binutils on pre-R6 kernels. For more references on why we -# can't use other methods to get the base address of VDSO please refer to -# the comments on that file. -# -ifndef CONFIG_CPU_MIPSR6 - ifeq ($(call ld-ifversion, -lt, 225000000, y),y) +ifdef CONFIG_MIPS_DISABLE_VDSO + ifndef CONFIG_MIPS_LD_CAN_LINK_VDSO $(warning MIPS VDSO requires binutils >= 2.25) - DISABLE_VDSO := y endif -endif - -# -# GCC (at least up to version 9.2) appears to emit function calls that make use -# of the GOT when targeting microMIPS, which we can't use in the VDSO due to -# the lack of relocations. As such, we disable the VDSO for microMIPS builds. -# -ifdef CONFIG_CPU_MICROMIPS - DISABLE_VDSO := y -endif - -ifeq ($(DISABLE_VDSO),y) obj-vdso-y := $(filter-out vgettimeofday.o, $(obj-vdso-y)) - ccflags-vdso += -DDISABLE_MIPS_VDSO endif # VDSO linker flags. diff --git a/arch/mips/vdso/vdso.lds.S b/arch/mips/vdso/vdso.lds.S index da4627430aba4..d90b65724d78e 100644 --- a/arch/mips/vdso/vdso.lds.S +++ b/arch/mips/vdso/vdso.lds.S @@ -91,7 +91,7 @@ PHDRS VERSION { LINUX_2.6 { -#ifndef DISABLE_MIPS_VDSO +#ifndef CONFIG_MIPS_DISABLE_VDSO global: __vdso_clock_gettime; __vdso_gettimeofday; From patchwork Tue Apr 28 22:14:17 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nathan Chancellor X-Patchwork-Id: 11515741 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id BD9A092C for ; Tue, 28 Apr 2020 22:14:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A21F220731 for ; Tue, 28 Apr 2020 22:14:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Iti+Hequ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726955AbgD1WOv (ORCPT ); Tue, 28 Apr 2020 18:14:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50692 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726884AbgD1WOr (ORCPT ); Tue, 28 Apr 2020 18:14:47 -0400 Received: from mail-ot1-x344.google.com (mail-ot1-x344.google.com [IPv6:2607:f8b0:4864:20::344]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AEA90C03C1AC; Tue, 28 Apr 2020 15:14:45 -0700 (PDT) Received: by mail-ot1-x344.google.com with SMTP id 72so35653389otu.1; Tue, 28 Apr 2020 15:14:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=D5XPjNeCefGZdrfYepQszWv1EoAyH1SJYjMY9egLiRQ=; b=Iti+HequGOL2PRuJbXnmbHCjiKuiBfJAzPaw8pDrLBFUO76wVbANTBmENBrQptVY+X FBumW6Q8M+cJTNNXqkgRIn/BpEW8C4gKFGoOESrw47zC2a6WrAzQH6qGn9YY1yOhQ67K EMVmi6vrNlI4Ug3rb/6YM1mmA9JQwUBotIlqKLfQAl7rKtBO/H7s0FurgDgDdqR/7Pdn byjVkaxjygBHj5EPMqqJRwqwdiN5qa4UJeWxCq8HnLKu8gG7oYy4IU2lUpV4fGn+fM18 vozwJ5GyPiHVyoBoWclyp9cS6to49xOt0mHwaou1wH+RgEcXp37H+5yOM3sNf7jGCsbP 3fAA== 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=D5XPjNeCefGZdrfYepQszWv1EoAyH1SJYjMY9egLiRQ=; b=clg0EzYuGYbeXL+48/jJkgshIL46NOiQMJ1wyYZ5aTMul3ihPuG1CebRh7/ZioU1zG f3UNaFyZH81J/dDuezwmtfvV8WLfUIf9yxmdy+ciSBGGEOyzGbdYyFn4F3WKuEBn74G4 wMe3LXHabmgHb6mXC49tCIc1r5R6OCKF53tcvUC59Yi2lMOzys+L7/dpUo/QRUSsL4TL lrE/UQO9u34rvnMErwpg/ISPIz02vCnXE41LY0niB9DKvTQEA+QDH61JGWYgLMGweug7 mMtFNOcXWwUXubnRqhq8vOALChZsLsTzQF/tRm+c+6y301wTvQNPHXB26v7K4wFrvZxh NVdQ== X-Gm-Message-State: AGi0Pub2QSjtOkZpvil/SgvRSCVBYvPxjWXYJ/opwtXIlZn8QSKoOYxG tQT4hJXfZ3ZSCdy6Yxh1tEM= X-Google-Smtp-Source: APiQypJKBJEUubwCVk6BCR1txO0tCzVgiFwxHfcCK5o8MX1rilWMul+BWNV6kI1sscPSPp8xdpLWng== X-Received: by 2002:a05:6830:1ac6:: with SMTP id r6mr1353744otc.311.1588112085030; Tue, 28 Apr 2020 15:14:45 -0700 (PDT) Received: from localhost.localdomain ([2604:1380:4111:8b00::1]) by smtp.gmail.com with ESMTPSA id 186sm5267476ooi.30.2020.04.28.15.14.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 28 Apr 2020 15:14:44 -0700 (PDT) From: Nathan Chancellor To: Thomas Bogendoerfer , Masahiro Yamada Cc: linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, linux-kbuild@vger.kernel.org, Nick Desaulniers , Fangrui Song , Sami Tolvanen , Dmitry Golovin , Sedat Dilek , Nathan Chancellor Subject: [PATCH v4 3/5] MIPS: Unconditionally specify '-EB' or '-EL' Date: Tue, 28 Apr 2020 15:14:17 -0700 Message-Id: <20200428221419.2530697-4-natechancellor@gmail.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200428221419.2530697-1-natechancellor@gmail.com> References: <20200423171807.29713-1-natechancellor@gmail.com> <20200428221419.2530697-1-natechancellor@gmail.com> MIME-Version: 1.0 X-Patchwork-Bot: notify Sender: linux-kbuild-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org This was all done to work around a GCC bug that has been fixed after 4.2. The kernel requires GCC 4.6 or newer so remove all of these hacks and just use the traditional flags. $ mips64-linux-gcc --version | head -n1 mips64-linux-gcc (GCC) 4.6.3 $ mips64-linux-gcc -EB -dM -E -C -x c /dev/null | grep MIPSE #define MIPSEB 1 #define __MIPSEB__ 1 #define _MIPSEB 1 #define __MIPSEB 1 $ mips64-linux-gcc -EL -dM -E -C -x c /dev/null | grep MIPSE #define __MIPSEL__ 1 #define MIPSEL 1 #define _MIPSEL 1 #define __MIPSEL 1 This is necessary when converting the MIPS VDSO to use $(LD) instead of $(CC) to link because the OUTPUT_FORMAT is defaulted to little endian and only flips to big endian when '-EB' is set on the command line. There is no issue currently because the compiler explicitly passes '-EB' or '-EL' to the linker regardless of whether or not it was provided by the user. Passing '-v' to VDSO_LDFLAGS shows: /libexec/gcc/mips64-linux/9.3.0/collect2 ... -EB ... even though '-EB' is nowhere to be found in KBUILD_CFLAGS. The VDSO Makefile already supports getting '-EB' or '-EL' from KBUILD_CFLAGS through a filter directive but '-EB' or '-EL' is not always present. If we do not do this, we will see the following error when compiling for big endian: $ make -j$(nproc) ARCH=mips CROSS_COMPILE=mips64-linux- \ 64r2el_defconfig arch/mips/vdso/ ... mips64-linux-ld: arch/mips/vdso/elf.o: compiled for a big endian system and target is little endian mips64-linux-ld: arch/mips/vdso/elf.o: endianness incompatible with that of the selected emulation mips64-linux-ld: failed to merge target specific data of file arch/mips/vdso/elf.o ... Remove this legacy hack and just use '-EB' and '-EL' unconditionally. Reported-by: Thomas Bogendoerfer Signed-off-by: Nathan Chancellor --- v3 -> v4: * New patch. arch/mips/Makefile | 25 ------------------------- 1 file changed, 25 deletions(-) diff --git a/arch/mips/Makefile b/arch/mips/Makefile index e1c44aed81565..301efb90b51ed 100644 --- a/arch/mips/Makefile +++ b/arch/mips/Makefile @@ -116,33 +116,8 @@ endif cflags-y += -ffreestanding -# -# We explicitly add the endianness specifier if needed, this allows -# to compile kernels with a toolchain for the other endianness. We -# carefully avoid to add it redundantly because gcc 3.3/3.4 complains -# when fed the toolchain default! -# -# Certain gcc versions up to gcc 4.1.1 (probably 4.2-subversion as of -# 2006-10-10 don't properly change the predefined symbols if -EB / -EL -# are used, so we kludge that here. A bug has been filed at -# http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29413. -# -# clang doesn't suffer from these issues and our checks against -dumpmachine -# don't work so well when cross compiling, since without providing --target -# clang's output will be based upon the build machine. So for clang we simply -# unconditionally specify -EB or -EL as appropriate. -# -ifdef CONFIG_CC_IS_CLANG cflags-$(CONFIG_CPU_BIG_ENDIAN) += -EB cflags-$(CONFIG_CPU_LITTLE_ENDIAN) += -EL -else -undef-all += -UMIPSEB -U_MIPSEB -U__MIPSEB -U__MIPSEB__ -undef-all += -UMIPSEL -U_MIPSEL -U__MIPSEL -U__MIPSEL__ -predef-be += -DMIPSEB -D_MIPSEB -D__MIPSEB -D__MIPSEB__ -predef-le += -DMIPSEL -D_MIPSEL -D__MIPSEL -D__MIPSEL__ -cflags-$(CONFIG_CPU_BIG_ENDIAN) += $(shell $(CC) -dumpmachine |grep -q 'mips.*el-.*' && echo -EB $(undef-all) $(predef-be)) -cflags-$(CONFIG_CPU_LITTLE_ENDIAN) += $(shell $(CC) -dumpmachine |grep -q 'mips.*el-.*' || echo -EL $(undef-all) $(predef-le)) -endif cflags-$(CONFIG_SB1XXX_CORELIS) += $(call cc-option,-mno-sched-prolog) \ -fno-omit-frame-pointer From patchwork Tue Apr 28 22:14:18 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nathan Chancellor X-Patchwork-Id: 11515743 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 722EB92C for ; Tue, 28 Apr 2020 22:14:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 55DBC2076A for ; Tue, 28 Apr 2020 22:14:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="b/C9LOZ0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726973AbgD1WOv (ORCPT ); Tue, 28 Apr 2020 18:14:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50698 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726898AbgD1WOr (ORCPT ); Tue, 28 Apr 2020 18:14:47 -0400 Received: from mail-ot1-x344.google.com (mail-ot1-x344.google.com [IPv6:2607:f8b0:4864:20::344]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4999EC03C1AD; Tue, 28 Apr 2020 15:14:47 -0700 (PDT) Received: by mail-ot1-x344.google.com with SMTP id z17so35708450oto.4; Tue, 28 Apr 2020 15:14:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=5MojLeIiS5IJ/f4OVpVWsw3ucrS28qn0/t/fHk4cEKI=; b=b/C9LOZ0PhFIybMMzacd5jkAEASReFP1A6oZuZTQSOyUW3Rmvy9DQHjLXwFZeuCXnk 0BJ0VMqjzl9Xk5f2oxAjSrdEmTLnBq+ALBBSt2BVxDo7VBQg0s8rXXuVlE0AXpsfV2MB ho5HS+pfA3QlVD78R+8yFZCqYlDzjmFcyfdGzy6wuTY5Qy6P8H/xkYC/5dy1OlhImz4t sGgzeAzDB4LL3pEj2Er8/yymkukWJ+sPhJATj8Glt3etrKDxrLemxrR1GAyytutqhUHc RrOwosNmI0y8reCfHdOJjFudRuAYIlnETabEKhOUWXXu0l7jAcLUoDnVUdH7C4GFxJQz VbBA== 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=5MojLeIiS5IJ/f4OVpVWsw3ucrS28qn0/t/fHk4cEKI=; b=X+py0a72r73bLk0wFBnpN3Cd9kUeC1VjC9uRCOXzWwZEq8eV2aSUxBkrYF2S/7VAIa Hq5IEF9h/WG1aNDxTyjLSqgGyYFOktgLn3F4AWZFrhKKl0gQwuDl7uhJdiT2pdfntwZm twsuBRU+JG2pEbahEGzp1P2OXbVoKMHTVCKcKXeAo4CtZMlK4USySsocRTJdX30dvkqV X2EjuthS6qMZ1N/dmL3xobBq2yHSxe1s8mCMpJ6cWDQqbHvLN2e/ux60QSyauXQ/lS57 dgxHhA/9XWtu5pbqD6afbGCgP7VvIFpmzI24zAii944ExusyTQQnj/5GiGcLBzoa9pb4 tIog== X-Gm-Message-State: AGi0Pub3UzTf+QeEtzOxZvdEuuYLcIE230L2ZSEwBk3gXvs7w6OP7cYW C6ZymaWUw632wY2yqLggjHU= X-Google-Smtp-Source: APiQypJfyklPMFQQYQL1OuANyjySeCQPdGYH7TjSCjrF2emF6AGXFPjeHCraQdzzIrRauzMdS8QFpQ== X-Received: by 2002:a9d:d06:: with SMTP id 6mr25675586oti.188.1588112086606; Tue, 28 Apr 2020 15:14:46 -0700 (PDT) Received: from localhost.localdomain ([2604:1380:4111:8b00::1]) by smtp.gmail.com with ESMTPSA id 186sm5267476ooi.30.2020.04.28.15.14.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 28 Apr 2020 15:14:45 -0700 (PDT) From: Nathan Chancellor To: Thomas Bogendoerfer , Masahiro Yamada Cc: linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, linux-kbuild@vger.kernel.org, Nick Desaulniers , Fangrui Song , Sami Tolvanen , Dmitry Golovin , Sedat Dilek , Nathan Chancellor Subject: [PATCH v4 4/5] MIPS: VDSO: Use $(LD) instead of $(CC) to link VDSO Date: Tue, 28 Apr 2020 15:14:18 -0700 Message-Id: <20200428221419.2530697-5-natechancellor@gmail.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200428221419.2530697-1-natechancellor@gmail.com> References: <20200423171807.29713-1-natechancellor@gmail.com> <20200428221419.2530697-1-natechancellor@gmail.com> MIME-Version: 1.0 X-Patchwork-Bot: notify Sender: linux-kbuild-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org Currently, the VDSO is being linked through $(CC). This does not match how the rest of the kernel links objects, which is through the $(LD) variable. When clang is built in a default configuration, it first attempts to use the target triple's default linker then the system's default linker, unless told otherwise through -fuse-ld=... We do not use -fuse-ld= because it can be brittle and we have support for invoking $(LD) directly. See commit fe00e50b2db8c ("ARM: 8858/1: vdso: use $(LD) instead of $(CC) to link VDSO") and commit 691efbedc60d2 ("arm64: vdso: use $(LD) instead of $(CC) to link VDSO") for examples of doing this in the VDSO. Do the same thing here. Replace the custom linking logic with $(cmd_ld) and ldflags-y so that $(LD) is respected. We need to explicitly add two flags to the linker that were implicitly passed by the compiler: -G 0 (which comes from ccflags-vdso) and --eh-frame-hdr. Before this patch (generated by adding '-v' to VDSO_LDFLAGS): /libexec/gcc/mips64-linux/9.3.0/collect2 \ -plugin /libexec/gcc/mips64-linux/9.3.0/liblto_plugin.so \ -plugin-opt=/libexec/gcc/mips64-linux/9.3.0/lto-wrapper \ -plugin-opt=-fresolution=/tmp/ccGEi5Ka.res \ --eh-frame-hdr \ -G 0 \ -EB \ -mips64r2 \ -shared \ -melf64btsmip \ -o arch/mips/vdso/vdso.so.dbg.raw \ -L/lib/gcc/mips64-linux/9.3.0/64 \ -L/lib/gcc/mips64-linux/9.3.0 \ -L/lib/gcc/mips64-linux/9.3.0/../../../../mips64-linux/lib \ -Bsymbolic \ --no-undefined \ -soname=linux-vdso.so.1 \ -EB \ --hash-style=sysv \ --build-id \ -T arch/mips/vdso/vdso.lds \ arch/mips/vdso/elf.o \ arch/mips/vdso/vgettimeofday.o \ arch/mips/vdso/sigreturn.o After this patch: /bin/mips64-linux-ld \ -m elf64btsmip \ -Bsymbolic \ --no-undefined \ -soname=linux-vdso.so.1 \ -EB \ -nostdlib \ -shared \ -G 0 \ --eh-frame-hdr \ --hash-style=sysv \ --build-id \ -T arch/mips/vdso/vdso.lds \ arch/mips/vdso/elf.o \ arch/mips/vdso/vgettimeofday.o arch/mips/vdso/sigreturn.o \ -o arch/mips/vdso/vdso.so.dbg.raw Note that we leave behind -mips64r2. Turns out that ld ignores it (see get_emulation in ld/ldmain.c). This is true of current trunk and 2.23, which is the minimum supported version for the kernel: https://sourceware.org/git/?p=binutils-gdb.git;a=blob;f=ld/ldmain.c;hb=aa4209e7b679afd74a3860ce25659e71cc4847d5#l593 https://sourceware.org/git/?p=binutils-gdb.git;a=blob;f=ld/ldmain.c;hb=a55e30b51bc6227d8d41f707654d0a5620978dcf#l641 Before this patch, LD=ld.lld did nothing: $ llvm-readelf -p.comment arch/mips/vdso/vdso.so.dbg | sed 's/(.*//' String dump of section '.comment': [ 0] ClangBuiltLinux clang version 11.0.0 After this patch, it does: $ llvm-readelf -p.comment arch/mips/vdso/vdso.so.dbg | sed 's/(.*//' String dump of section '.comment': [ 0] Linker: LLD 11.0.0 [ 62] ClangBuiltLinux clang version 11.0.0 Link: https://github.com/ClangBuiltLinux/linux/issues/785 Signed-off-by: Nathan Chancellor --- v3 -> v4: * Improve commit message to show that ld command is effectively the same as the one generated by GCC. * Add '-G 0' and '--eh-frame-hdr' because they were added by GCC. v2 -> v3: * New patch. arch/mips/vdso/Makefile | 13 ++++--------- 1 file changed, 4 insertions(+), 9 deletions(-) diff --git a/arch/mips/vdso/Makefile b/arch/mips/vdso/Makefile index 92b53d1df42c3..2e64c7600eead 100644 --- a/arch/mips/vdso/Makefile +++ b/arch/mips/vdso/Makefile @@ -60,10 +60,9 @@ ifdef CONFIG_MIPS_DISABLE_VDSO endif # VDSO linker flags. -VDSO_LDFLAGS := \ - -Wl,-Bsymbolic -Wl,--no-undefined -Wl,-soname=linux-vdso.so.1 \ - $(addprefix -Wl$(comma),$(filter -E%,$(KBUILD_CFLAGS))) \ - -nostdlib -shared -Wl,--hash-style=sysv -Wl,--build-id +ldflags-y := -Bsymbolic --no-undefined -soname=linux-vdso.so.1 \ + $(filter -E%,$(KBUILD_CFLAGS)) -nostdlib -shared \ + -G 0 --eh-frame-hdr --hash-style=sysv --build-id -T CFLAGS_REMOVE_vdso.o = -pg @@ -82,11 +81,7 @@ quiet_cmd_vdso_mips_check = VDSOCHK $@ # quiet_cmd_vdsold_and_vdso_check = LD $@ - cmd_vdsold_and_vdso_check = $(cmd_vdsold); $(cmd_vdso_check); $(cmd_vdso_mips_check) - -quiet_cmd_vdsold = VDSO $@ - cmd_vdsold = $(CC) $(c_flags) $(VDSO_LDFLAGS) \ - -Wl,-T $(filter %.lds,$^) $(filter %.o,$^) -o $@ + cmd_vdsold_and_vdso_check = $(cmd_ld); $(cmd_vdso_check); $(cmd_vdso_mips_check) quiet_cmd_vdsoas_o_S = AS $@ cmd_vdsoas_o_S = $(CC) $(a_flags) -c -o $@ $< From patchwork Tue Apr 28 22:14:19 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nathan Chancellor X-Patchwork-Id: 11515749 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id B764A15AB for ; Tue, 28 Apr 2020 22:14:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9DF352076A for ; Tue, 28 Apr 2020 22:14:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="cboZAHaR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726948AbgD1WO6 (ORCPT ); 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Tue, 28 Apr 2020 15:14:47 -0700 (PDT) From: Nathan Chancellor To: Thomas Bogendoerfer , Masahiro Yamada Cc: linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, linux-kbuild@vger.kernel.org, Nick Desaulniers , Fangrui Song , Sami Tolvanen , Dmitry Golovin , Sedat Dilek , Nathan Chancellor Subject: [PATCH v4 5/5] MIPS: VDSO: Allow ld.lld to link the VDSO Date: Tue, 28 Apr 2020 15:14:19 -0700 Message-Id: <20200428221419.2530697-6-natechancellor@gmail.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200428221419.2530697-1-natechancellor@gmail.com> References: <20200423171807.29713-1-natechancellor@gmail.com> <20200428221419.2530697-1-natechancellor@gmail.com> MIME-Version: 1.0 X-Patchwork-Bot: notify Sender: linux-kbuild-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org Currently, when linking with ld.lld, this warning pops up: arch/mips/vdso/Makefile:70: MIPS VDSO requires binutils >= 2.25 CONFIG_LD_VERSION is set with scripts/ld-version.sh, which is specific to GNU ld. It returns 0 for ld.lld so CONFIG_MIPS_LD_CAN_LINK_VDSO does not set. ld.lld has a completely different versioning scheme (as it follows LLVM's versioning) and it does not have the issue mentioned in the comment block so it should be allowed to link the VDSO. With this patch, the VDSO successfully links and shows P_MIPS_PC32 in vgettimeofday.o. $ llvm-objdump -Dr arch/mips/vdso/vgettimeofday.o | grep R_MIPS_PC32 00000024: R_MIPS_PC32 _start 000000b0: R_MIPS_PC32 _start 000002bc: R_MIPS_PC32 _start 0000036c: R_MIPS_PC32 _start 00000468: R_MIPS_PC32 _start Reported-by: Dmitry Golovin Signed-off-by: Nathan Chancellor Link: https://github.com/ClangBuiltLinux/linux/issues/785 Link: https://github.com/llvm/llvm-project/commit/e364e2e9ce50c12eb2bf093560e1a1a8544d455a --- v3 -> v4: * No changes. v2 -> v3: * No changes. v1 -> v2: * Move into Kconfig so that the warning does not happen. arch/mips/vdso/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/mips/vdso/Kconfig b/arch/mips/vdso/Kconfig index 36a52158d849b..7aec721398d59 100644 --- a/arch/mips/vdso/Kconfig +++ b/arch/mips/vdso/Kconfig @@ -12,7 +12,7 @@ # the lack of relocations. As such, we disable the VDSO for microMIPS builds. config MIPS_LD_CAN_LINK_VDSO - def_bool LD_VERSION >= 225000000 + def_bool LD_VERSION >= 225000000 || LD_IS_LLD config MIPS_DISABLE_VDSO def_bool CPU_MICROMIPS || (!CPU_MIPSR6 && !MIPS_LD_CAN_LINK_VDSO)