From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kees Cook Subject: [PATCH v3 02/29] powerpc: Remove PT_NOTE workaround Date: Tue, 29 Oct 2019 14:13:24 -0700 Message-ID: <20191029211351.13243-3-keescook@chromium.org> References: <20191029211351.13243-1-keescook@chromium.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20191029211351.13243-1-keescook@chromium.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Borislav Petkov Cc: linux-arch@vger.kernel.org, linux-s390@vger.kernel.org, Michal Simek , linux-ia64@vger.kernel.org, Kees Cook , Arnd Bergmann , Michael Ellerman , Dave Hansen , Segher Boessenkool , linuxppc-dev@lists.ozlabs.org, Heiko Carstens , Yoshinori Sato , Andy Lutomirski , linux-alpha@vger.kernel.org, Rick Edgecombe , Will Deacon , linux-arm-kernel@lists.infradead.org, linux-c6x-dev@linux-c6x.org List-Id: linux-arch.vger.kernel.org In preparation for moving NOTES into RO_DATA, remove the PT_NOTE workaround since the kernel requires at least gcc 4.6 now. Signed-off-by: Kees Cook Acked-by: Michael Ellerman --- arch/powerpc/kernel/vmlinux.lds.S | 24 ++---------------------- 1 file changed, 2 insertions(+), 22 deletions(-) diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S index 81e672654789..a3c8492b2b19 100644 --- a/arch/powerpc/kernel/vmlinux.lds.S +++ b/arch/powerpc/kernel/vmlinux.lds.S @@ -20,20 +20,6 @@ ENTRY(_stext) PHDRS { kernel PT_LOAD FLAGS(7); /* RWX */ note PT_NOTE FLAGS(0); - dummy PT_NOTE FLAGS(0); - - /* binutils < 2.18 has a bug that makes it misbehave when taking an - ELF file with all segments at load address 0 as input. This - happens when running "strip" on vmlinux, because of the AT() magic - in this linker script. People using GCC >= 4.2 won't run into - this problem, because the "build-id" support will put some data - into the "notes" segment (at a non-zero load address). - - To work around this, we force some data into both the "dummy" - segment and the kernel segment, so the dummy segment will get a - non-zero load address. It's not enough to always create the - "notes" segment, since if nothing gets assigned to it, its load - address will be zero. */ } #ifdef CONFIG_PPC64 @@ -178,14 +164,8 @@ SECTIONS EXCEPTION_TABLE(0) NOTES :kernel :note - - /* The dummy segment contents for the bug workaround mentioned above - near PHDRS. */ - .dummy : AT(ADDR(.dummy) - LOAD_OFFSET) { - LONG(0) - LONG(0) - LONG(0) - } :kernel :dummy + /* Restore program header away from PT_NOTE. */ + .dummy : { *(.dummy) } :kernel /* * Init sections discarded at runtime -- 2.17.1 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-f196.google.com ([209.85.215.196]:44298 "EHLO mail-pg1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729072AbfJ2VOH (ORCPT ); Tue, 29 Oct 2019 17:14:07 -0400 Received: by mail-pg1-f196.google.com with SMTP id e10so10481803pgd.11 for ; Tue, 29 Oct 2019 14:14:05 -0700 (PDT) From: Kees Cook Subject: [PATCH v3 02/29] powerpc: Remove PT_NOTE workaround Date: Tue, 29 Oct 2019 14:13:24 -0700 Message-ID: <20191029211351.13243-3-keescook@chromium.org> In-Reply-To: <20191029211351.13243-1-keescook@chromium.org> References: <20191029211351.13243-1-keescook@chromium.org> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Borislav Petkov Cc: Kees Cook , Rick Edgecombe , Segher Boessenkool , Dave Hansen , Andy Lutomirski , Arnd Bergmann , Michael Ellerman , Heiko Carstens , Will Deacon , linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-ia64@vger.kernel.org, linux-s390@vger.kernel.org, linux-c6x-dev@linux-c6x.org, Yoshinori Sato , Michal Simek Message-ID: <20191029211324.I8XR4yOrUfSK4KZabZ8VXH3qvgJ530U2LeMCqAFPXHQ@z> In preparation for moving NOTES into RO_DATA, remove the PT_NOTE workaround since the kernel requires at least gcc 4.6 now. Signed-off-by: Kees Cook Acked-by: Michael Ellerman --- arch/powerpc/kernel/vmlinux.lds.S | 24 ++---------------------- 1 file changed, 2 insertions(+), 22 deletions(-) diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S index 81e672654789..a3c8492b2b19 100644 --- a/arch/powerpc/kernel/vmlinux.lds.S +++ b/arch/powerpc/kernel/vmlinux.lds.S @@ -20,20 +20,6 @@ ENTRY(_stext) PHDRS { kernel PT_LOAD FLAGS(7); /* RWX */ note PT_NOTE FLAGS(0); - dummy PT_NOTE FLAGS(0); - - /* binutils < 2.18 has a bug that makes it misbehave when taking an - ELF file with all segments at load address 0 as input. This - happens when running "strip" on vmlinux, because of the AT() magic - in this linker script. People using GCC >= 4.2 won't run into - this problem, because the "build-id" support will put some data - into the "notes" segment (at a non-zero load address). - - To work around this, we force some data into both the "dummy" - segment and the kernel segment, so the dummy segment will get a - non-zero load address. It's not enough to always create the - "notes" segment, since if nothing gets assigned to it, its load - address will be zero. */ } #ifdef CONFIG_PPC64 @@ -178,14 +164,8 @@ SECTIONS EXCEPTION_TABLE(0) NOTES :kernel :note - - /* The dummy segment contents for the bug workaround mentioned above - near PHDRS. */ - .dummy : AT(ADDR(.dummy) - LOAD_OFFSET) { - LONG(0) - LONG(0) - LONG(0) - } :kernel :dummy + /* Restore program header away from PT_NOTE. */ + .dummy : { *(.dummy) } :kernel /* * Init sections discarded at runtime -- 2.17.1