From patchwork Thu Mar 19 13:03:52 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 11447229 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 7AB9A17E6 for ; Thu, 19 Mar 2020 13:30:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5828120789 for ; Thu, 19 Mar 2020 13:30:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584624617; bh=2+JddXm05lMAvMt7a5HtaUlUsXMzX06xKsrUO7VAvF8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=exQIM2Mg6T1reDF1qYd9X06I3vPHGebvr+0l2QPdGCwngsmXAGOJlLe/065WYqI04 42NlZM1ZL1UmitJybboQBE9UbyoawzAm4UQ46YJjDgBpqb5xMAFeViCgtJRoyJPday pAjBXUVwtbBdjx9mQ7rMhjhF3WUuIWr0sruDIBLo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728489AbgCSNaM (ORCPT ); Thu, 19 Mar 2020 09:30:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:46986 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728927AbgCSNWC (ORCPT ); Thu, 19 Mar 2020 09:22:02 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6A54420724; Thu, 19 Mar 2020 13:22:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584624120; bh=2+JddXm05lMAvMt7a5HtaUlUsXMzX06xKsrUO7VAvF8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ye9CSkUKT/3f+pmUOp0MLi/8cCcc5kR+VhrkJIONf/x22DSMN/CB9qO9XNX1ERdT1 cEGjXqNoXmfHk52OPIc8lUUgI3hfpE00A26hebthUwePtFCwB5i9nppcZ/5Grc0Jbh aVlKP9zyQWKQO5uIm51PS4NmLMYJLrmf1npNKQGg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Bruce Ashfield , Victor Kamensky , Paul Burton , linux-mips@vger.kernel.org, Ralf Baechle , James Hogan , Vincenzo Frascino , richard.purdie@linuxfoundation.org, Sasha Levin Subject: [PATCH 5.4 14/60] mips: vdso: fix jalr t9 crash in vdso code Date: Thu, 19 Mar 2020 14:03:52 +0100 Message-Id: <20200319123923.535642309@linuxfoundation.org> X-Mailer: git-send-email 2.25.2 In-Reply-To: <20200319123919.441695203@linuxfoundation.org> References: <20200319123919.441695203@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: linux-mips-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org From: Victor Kamensky [ Upstream commit d3f703c4359ff06619b2322b91f69710453e6b6d ] Observed that when kernel is built with Yocto mips64-poky-linux-gcc, and mips64-poky-linux-gnun32-gcc toolchain, resulting vdso contains 'jalr t9' instructions in its code and since in vdso case nobody sets GOT table code crashes when instruction reached. On other hand observed that when kernel is built mips-poky-linux-gcc toolchain, the same 'jalr t9' instruction are replaced with PC relative function calls using 'bal' instructions. The difference boils down to -mrelax-pic-calls and -mexplicit-relocs gcc options that gets different default values depending on gcc target triplets and corresponding binutils. -mrelax-pic-calls got enabled by default only in mips-poky-linux-gcc case. MIPS binutils ld relies on R_MIPS_JALR relocation to convert 'jalr t9' into 'bal' and such relocation is generated only if -mrelax-pic-calls option is on. Please note 'jalr t9' conversion to 'bal' can happen only to static functions. These static PIC calls use mips local GOT entries that are supposed to be filled with start of DSO value by run-time linker (missing in VDSO case) and they do not have dynamic relocations. Global mips GOT entries must have dynamic relocations and they should be prevented by cmd_vdso_check Makefile rule. Solution call out -mrelax-pic-calls and -mexplicit-relocs options explicitly while compiling MIPS vdso code. That would get correct and consistent between different toolchains behaviour. Reported-by: Bruce Ashfield Signed-off-by: Victor Kamensky Signed-off-by: Paul Burton Cc: linux-mips@vger.kernel.org Cc: Ralf Baechle Cc: James Hogan Cc: Vincenzo Frascino Cc: richard.purdie@linuxfoundation.org Signed-off-by: Sasha Levin --- arch/mips/vdso/Makefile | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/mips/vdso/Makefile b/arch/mips/vdso/Makefile index 996a934ece7d6..3fa4bbe1bae53 100644 --- a/arch/mips/vdso/Makefile +++ b/arch/mips/vdso/Makefile @@ -29,6 +29,7 @@ endif cflags-vdso := $(ccflags-vdso) \ $(filter -W%,$(filter-out -Wa$(comma)%,$(KBUILD_CFLAGS))) \ -O3 -g -fPIC -fno-strict-aliasing -fno-common -fno-builtin -G 0 \ + -mrelax-pic-calls -mexplicit-relocs \ -fno-stack-protector -fno-jump-tables -DDISABLE_BRANCH_PROFILING \ $(call cc-option, -fno-asynchronous-unwind-tables) \ $(call cc-option, -fno-stack-protector) From patchwork Thu Mar 19 13:03:54 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 11447167 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 A3E241667 for ; Thu, 19 Mar 2020 13:22:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 845E521841 for ; Thu, 19 Mar 2020 13:22:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584624132; bh=q1ZJfqZkpoH40GqRMjB4mYTdZMps4c9CnvYPqZJ7INI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ru9m5ApM+UwxxCY8O2Ll28OBDMvueSUqijjiGvFEb8Uh70uu7CnWM6mztDe8vLp7K 4S6MMeqaxUW2mrUX6aJY7koYum3+boic5kkFGM6OXz6rHfvclO28lewOt+7JQ16In0 JB1ldEt787IApJu65O8j41Fx48p3zl1kXx4wsxmI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730038AbgCSNWJ (ORCPT ); Thu, 19 Mar 2020 09:22:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:47148 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729778AbgCSNWI (ORCPT ); Thu, 19 Mar 2020 09:22:08 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id BE71E208D6; Thu, 19 Mar 2020 13:22:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584624127; bh=q1ZJfqZkpoH40GqRMjB4mYTdZMps4c9CnvYPqZJ7INI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tbI5v9DDcEhtYaRq21+3L/HA4G4zaeJbTpRgJmtSzjLZxAwcBiD+QOeufbdWu6D8y QV9buRFBq28KIvwgZRPGw+YjeSNEm/S6GUrGPItSslgsEAZLWNCWubU166owBpyxXt X5Xde+U1tjCeQYo1M/FbyZ2rFnphv4Gf6wyGhDtw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Victor Kamensky , Paul Burton , linux-mips@vger.kernel.org, Ralf Baechle , James Hogan , Vincenzo Frascino , bruce.ashfield@gmail.com, richard.purdie@linuxfoundation.org, Sasha Levin Subject: [PATCH 5.4 16/60] mips: vdso: add build time check that no jalr t9 calls left Date: Thu, 19 Mar 2020 14:03:54 +0100 Message-Id: <20200319123924.238277162@linuxfoundation.org> X-Mailer: git-send-email 2.25.2 In-Reply-To: <20200319123919.441695203@linuxfoundation.org> References: <20200319123919.441695203@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: linux-mips-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org From: Victor Kamensky [ Upstream commit 976c23af3ee5bd3447a7bfb6c356ceb4acf264a6 ] vdso shared object cannot have GOT based PIC 'jalr t9' calls because nobody set GOT table in vdso. Contributing into vdso .o files are compiled in PIC mode and as result for internal static functions calls compiler will generate 'jalr t9' instructions. Those are supposed to be converted into PC relative 'bal' calls by linker when relocation are processed. Mips global GOT entries do have dynamic relocations and they will be caught by cmd_vdso_check Makefile rule. Static PIC calls go through mips local GOT entries that do not have dynamic relocations. For those 'jalr t9' calls could be present but without dynamic relocations and they need to be converted to 'bal' calls by linker. Add additional build time check to make sure that no 'jalr t9' slip through because of some toolchain misconfiguration that prevents 'jalr t9' to 'bal' conversion. Signed-off-by: Victor Kamensky Signed-off-by: Paul Burton Cc: linux-mips@vger.kernel.org Cc: Ralf Baechle Cc: James Hogan Cc: Vincenzo Frascino Cc: bruce.ashfield@gmail.com Cc: richard.purdie@linuxfoundation.org Signed-off-by: Sasha Levin --- arch/mips/vdso/Makefile | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/arch/mips/vdso/Makefile b/arch/mips/vdso/Makefile index b6b1eb638fb14..08c835d48520b 100644 --- a/arch/mips/vdso/Makefile +++ b/arch/mips/vdso/Makefile @@ -92,12 +92,18 @@ CFLAGS_REMOVE_vdso.o = -pg GCOV_PROFILE := n UBSAN_SANITIZE := n +# Check that we don't have PIC 'jalr t9' calls left +quiet_cmd_vdso_mips_check = VDSOCHK $@ + cmd_vdso_mips_check = if $(OBJDUMP) --disassemble $@ | egrep -h "jalr.*t9" > /dev/null; \ + then (echo >&2 "$@: PIC 'jalr t9' calls are not supported"; \ + rm -f $@; /bin/false); fi + # # Shared build commands. # quiet_cmd_vdsold_and_vdso_check = LD $@ - cmd_vdsold_and_vdso_check = $(cmd_vdsold); $(cmd_vdso_check) + 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) \ From patchwork Thu Mar 19 13:03:58 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 11447173 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 6BDB31667 for ; Thu, 19 Mar 2020 13:23:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4AE37214D8 for ; Thu, 19 Mar 2020 13:23:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584624192; bh=9g2gIbbLljcopMLsa1wpkRfrnY5cLA9djOVfX6VbqYg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=l0vQB544Ierft3Yw62pfC/tYy6ef9Ao6cLsY+8M5cZ3Uv+RYg9FTuGKtnyjF6wLMi 3qN3zjDdI547m49G9OCIjV+0WIqafw4lB2NgkrLcVm0TBc+QeUvQbBTqD6FgJESrrm dWJf4IUlMrxuaqslYVNYQL8YZEqpoYSIavCcN0jg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730317AbgCSNXL (ORCPT ); Thu, 19 Mar 2020 09:23:11 -0400 Received: from mail.kernel.org ([198.145.29.99]:48982 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730313AbgCSNXK (ORCPT ); Thu, 19 Mar 2020 09:23:10 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4F13C20724; Thu, 19 Mar 2020 13:23:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584624189; bh=9g2gIbbLljcopMLsa1wpkRfrnY5cLA9djOVfX6VbqYg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FR2ctbiNrY3apd3xUcg9lW7/ZKMeB8vO1ze0a194ounXr2w1pB969Q8NCxZRA4awg r9KXj05k4/TGgqa5BtwrOBb/b8JSxE4E0Im+iW2jRdOO5/31ODTVuLTp8RyPsYlLU3 hJ0OQFAgw/oFsKUoZIZsQH0zCfvcWMJzvRMhauTg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Nathan Chancellor , Nick Desaulniers , Paul Burton , Ralf Baechle , linux-mips@vger.kernel.org, clang-built-linux@googlegroups.com, Sasha Levin Subject: [PATCH 5.4 20/60] MIPS: vdso: Wrap -mexplicit-relocs in cc-option Date: Thu, 19 Mar 2020 14:03:58 +0100 Message-Id: <20200319123925.617729599@linuxfoundation.org> X-Mailer: git-send-email 2.25.2 In-Reply-To: <20200319123919.441695203@linuxfoundation.org> References: <20200319123919.441695203@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: linux-mips-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org From: Nathan Chancellor [ Upstream commit 72cf3b3df423c1bbd8fa1056fed009d3a260f8a9 ] Clang does not support this option and errors out: clang-11: error: unknown argument: '-mexplicit-relocs' Clang does not appear to need this flag like GCC does because the jalr check that was added in commit 976c23af3ee5 ("mips: vdso: add build time check that no 'jalr t9' calls left") passes just fine with $ make ARCH=mips CC=clang CROSS_COMPILE=mipsel-linux-gnu- malta_defconfig arch/mips/vdso/ even before commit d3f703c4359f ("mips: vdso: fix 'jalr t9' crash in vdso code"). -mrelax-pic-calls has been supported since clang 9, which is the earliest version that could build a working MIPS kernel, and it is the default for clang so just leave it be. Fixes: d3f703c4359f ("mips: vdso: fix 'jalr t9' crash in vdso code") Link: https://github.com/ClangBuiltLinux/linux/issues/890 Signed-off-by: Nathan Chancellor Reviewed-by: Nick Desaulniers Tested-by: Nick Desaulniers Signed-off-by: Paul Burton Cc: Ralf Baechle Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: clang-built-linux@googlegroups.com Signed-off-by: Sasha Levin --- arch/mips/vdso/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/mips/vdso/Makefile b/arch/mips/vdso/Makefile index 08c835d48520b..3dcfdee678fb9 100644 --- a/arch/mips/vdso/Makefile +++ b/arch/mips/vdso/Makefile @@ -29,7 +29,7 @@ endif cflags-vdso := $(ccflags-vdso) \ $(filter -W%,$(filter-out -Wa$(comma)%,$(KBUILD_CFLAGS))) \ -O3 -g -fPIC -fno-strict-aliasing -fno-common -fno-builtin -G 0 \ - -mrelax-pic-calls -mexplicit-relocs \ + -mrelax-pic-calls $(call cc-option, -mexplicit-relocs) \ -fno-stack-protector -fno-jump-tables -DDISABLE_BRANCH_PROFILING \ $(call cc-option, -fno-asynchronous-unwind-tables) \ $(call cc-option, -fno-stack-protector)