From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kees Cook Subject: [PATCH 5/9] Add RUNTIME_DISCARD_EXIT to generic DISCARDS Date: Thu, 27 Feb 2020 16:22:40 -0800 Message-ID: <20200228002244.15240-6-keescook@chromium.org> References: <20200228002244.15240-1-keescook@chromium.org> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20200228002244.15240-1-keescook@chromium.org> Sender: linux-kernel-owner@vger.kernel.org To: Borislav Petkov Cc: Kees Cook , "H.J. Lu" , Russell King , Catalin Marinas , Will Deacon , Mark Rutland , Peter Collingbourne , James Morse , Arnd Bergmann , Masahiro Yamada , x86@kernel.org, linux-arm-kernel@lists.infradead.org, linux-arch@vger.kernel.org, linux-kbuild@vger.kernel.org, clang-built-linux@googlegroups.com, linux-kernel@vger.kernel.org List-Id: linux-arch.vger.kernel.org From: "H.J. Lu" In x86 kernel, .exit.text and .exit.data sections are discarded at runtime, not by linker. Add RUNTIME_DISCARD_EXIT to generic DISCARDS and define it in x86 kernel linker script to keep them. Signed-off-by: H.J. Lu Link: https://lore.kernel.org/r/20200130224337.4150-1-hjl.tools@gmail.com Signed-off-by: Kees Cook --- arch/x86/kernel/vmlinux.lds.S | 1 + include/asm-generic/vmlinux.lds.h | 10 ++++++++-- 2 files changed, 9 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index 1e345f302a46..1e12c097d09b 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -21,6 +21,7 @@ #define LOAD_OFFSET __START_KERNEL_map #endif +#define RUNTIME_DISCARD_EXIT #define EMITS_PT_NOTE #define RO_EXCEPTION_TABLE_ALIGN 16 diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 303597e51396..1797f2c9bb41 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -894,10 +894,16 @@ * section definitions so that such archs put those in earlier section * definitions. */ +#ifdef RUNTIME_DISCARD_EXIT +#define EXIT_DISCARDS +#else +#define EXIT_DISCARDS \ + EXIT_TEXT \ + EXIT_DATA +#endif #define DISCARDS \ /DISCARD/ : { \ - EXIT_TEXT \ - EXIT_DATA \ + EXIT_DISCARDS \ EXIT_CALL \ *(.discard) \ *(.discard.*) \ -- 2.20.1 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf1-f193.google.com ([209.85.210.193]:46002 "EHLO mail-pf1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730447AbgB1AW4 (ORCPT ); Thu, 27 Feb 2020 19:22:56 -0500 Received: by mail-pf1-f193.google.com with SMTP id 2so713893pfg.12 for ; Thu, 27 Feb 2020 16:22:55 -0800 (PST) From: Kees Cook Subject: [PATCH 5/9] Add RUNTIME_DISCARD_EXIT to generic DISCARDS Date: Thu, 27 Feb 2020 16:22:40 -0800 Message-ID: <20200228002244.15240-6-keescook@chromium.org> In-Reply-To: <20200228002244.15240-1-keescook@chromium.org> References: <20200228002244.15240-1-keescook@chromium.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-arch-owner@vger.kernel.org List-ID: To: Borislav Petkov Cc: Kees Cook , "H.J. Lu" , Russell King , Catalin Marinas , Will Deacon , Mark Rutland , Peter Collingbourne , James Morse , Arnd Bergmann , Masahiro Yamada , x86@kernel.org, linux-arm-kernel@lists.infradead.org, linux-arch@vger.kernel.org, linux-kbuild@vger.kernel.org, clang-built-linux@googlegroups.com, linux-kernel@vger.kernel.org Message-ID: <20200228002240.zTanaxAhzPQqznuo9iAbeoHK_qtYNOT_nKIvgz5W8Aw@z> From: "H.J. Lu" In x86 kernel, .exit.text and .exit.data sections are discarded at runtime, not by linker. Add RUNTIME_DISCARD_EXIT to generic DISCARDS and define it in x86 kernel linker script to keep them. Signed-off-by: H.J. Lu Link: https://lore.kernel.org/r/20200130224337.4150-1-hjl.tools@gmail.com Signed-off-by: Kees Cook --- arch/x86/kernel/vmlinux.lds.S | 1 + include/asm-generic/vmlinux.lds.h | 10 ++++++++-- 2 files changed, 9 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index 1e345f302a46..1e12c097d09b 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -21,6 +21,7 @@ #define LOAD_OFFSET __START_KERNEL_map #endif +#define RUNTIME_DISCARD_EXIT #define EMITS_PT_NOTE #define RO_EXCEPTION_TABLE_ALIGN 16 diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 303597e51396..1797f2c9bb41 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -894,10 +894,16 @@ * section definitions so that such archs put those in earlier section * definitions. */ +#ifdef RUNTIME_DISCARD_EXIT +#define EXIT_DISCARDS +#else +#define EXIT_DISCARDS \ + EXIT_TEXT \ + EXIT_DATA +#endif #define DISCARDS \ /DISCARD/ : { \ - EXIT_TEXT \ - EXIT_DATA \ + EXIT_DISCARDS \ EXIT_CALL \ *(.discard) \ *(.discard.*) \ -- 2.20.1