From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ard Biesheuvel Subject: [PATCH 1/5] arch: enable relative relocations for arm64, power, x86, s390 and x86 Date: Mon, 14 Aug 2017 11:52:27 +0100 Message-ID: <20170814105231.14608-2-ard.biesheuvel@linaro.org> References: <20170814105231.14608-1-ard.biesheuvel@linaro.org> Return-path: In-Reply-To: <20170814105231.14608-1-ard.biesheuvel@linaro.org> Sender: linux-kernel-owner@vger.kernel.org To: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org Cc: Ard Biesheuvel , "H. Peter Anvin" , Arnd Bergmann , Heiko Carstens , Kees Cook , Will Deacon , Michael Ellerman , Thomas Garnier , Thomas Gleixner , "Serge E. Hallyn" , Bjorn Helgaas , Benjamin Herrenschmidt , Paul Mackerras , Catalin Marinas , Petr Mladek , Ingo Molnar , James Morris , Andrew Morton , Nicolas Pitre , Steven Rostedt List-Id: linux-arch.vger.kernel.org Before updating certain subsystems to use place relative 32-bit relocations in special sections, to save space and reduce the number of absolute relocations that need to be processed at runtime by relocatable kernels, introduce a new Kconfig symbol and define it for some architectures that should be able to support and benefit from it. Cc: Catalin Marinas Cc: Will Deacon Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Michael Ellerman Cc: Martin Schwidefsky Cc: Heiko Carstens Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: x86@kernel.org Signed-off-by: Ard Biesheuvel --- arch/Kconfig | 10 ++++++++++ arch/arm64/Kconfig | 1 + arch/arm64/kernel/vmlinux.lds.S | 2 +- arch/powerpc/Kconfig | 1 + arch/s390/Kconfig | 1 + arch/x86/Kconfig | 1 + 6 files changed, 15 insertions(+), 1 deletion(-) diff --git a/arch/Kconfig b/arch/Kconfig index 21d0089117fe..4e77d8e8697e 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -940,4 +940,14 @@ config REFCOUNT_FULL against various use-after-free conditions that can be used in security flaw exploits. +config HAVE_ARCH_PREL32_RELOCATIONS + bool + help + May be selected by an architecture if it supports place-relative + 32-bit relocations, both in the toolchain and in the module loader, + in which case relative references can be used in special sections + for PCI fixup, initcalls etc which are only half the size on 64 bit + architectures, and don't require runtime relocation on relocatable + kernels. + source "kernel/gcov/Kconfig" diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index dfd908630631..ce05d2d8143e 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -72,6 +72,7 @@ config ARM64 select HAVE_ARCH_KGDB select HAVE_ARCH_MMAP_RND_BITS select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT + select HAVE_ARCH_PREL32_RELOCATIONS select HAVE_ARCH_SECCOMP_FILTER select HAVE_ARCH_TRACEHOOK select HAVE_ARCH_TRANSPARENT_HUGEPAGE diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S index 987a00ee446c..5849bd4e2b06 100644 --- a/arch/arm64/kernel/vmlinux.lds.S +++ b/arch/arm64/kernel/vmlinux.lds.S @@ -171,7 +171,7 @@ SECTIONS CON_INITCALL SECURITY_INITCALL INIT_RAM_FS - *(.init.rodata.* .init.bss) /* from the EFI stub */ + *(.init.rodata.* .init.bss .init.discard.*) /* from the EFI stub */ } .exit.data : { ARM_EXIT_KEEP(EXIT_DATA) diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 36f858c37ca7..f7e60ed5bdd0 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -163,6 +163,7 @@ config PPC select HAVE_ARCH_KGDB select HAVE_ARCH_MMAP_RND_BITS select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT + select HAVE_ARCH_PREL32_RELOCATIONS select HAVE_ARCH_SECCOMP_FILTER select HAVE_ARCH_TRACEHOOK select ARCH_HAS_STRICT_KERNEL_RWX if (PPC_BOOK3S_64 && !RELOCATABLE && !HIBERNATION) diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index 7eeb75d758c1..1206cc7daa0d 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -127,6 +127,7 @@ config S390 select HAVE_ARCH_AUDITSYSCALL select HAVE_ARCH_JUMP_LABEL select CPU_NO_EFFICIENT_FFS if !HAVE_MARCH_Z9_109_FEATURES + select HAVE_ARCH_PREL32_RELOCATIONS select HAVE_ARCH_SECCOMP_FILTER select HAVE_ARCH_SOFT_DIRTY select HAVE_ARCH_TRACEHOOK diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 781521b7cf9e..77246125883e 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -112,6 +112,7 @@ config X86 select HAVE_ARCH_MMAP_RND_BITS if MMU select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT + select HAVE_ARCH_PREL32_RELOCATIONS select HAVE_ARCH_SECCOMP_FILTER select HAVE_ARCH_TRACEHOOK select HAVE_ARCH_TRANSPARENT_HUGEPAGE -- 2.11.0 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f180.google.com ([209.85.128.180]:36030 "EHLO mail-wr0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752748AbdHNKxE (ORCPT ); Mon, 14 Aug 2017 06:53:04 -0400 Received: by mail-wr0-f180.google.com with SMTP id y41so8602658wrd.3 for ; Mon, 14 Aug 2017 03:53:03 -0700 (PDT) From: Ard Biesheuvel Subject: [PATCH 1/5] arch: enable relative relocations for arm64, power, x86, s390 and x86 Date: Mon, 14 Aug 2017 11:52:27 +0100 Message-ID: <20170814105231.14608-2-ard.biesheuvel@linaro.org> In-Reply-To: <20170814105231.14608-1-ard.biesheuvel@linaro.org> References: <20170814105231.14608-1-ard.biesheuvel@linaro.org> Sender: linux-arch-owner@vger.kernel.org List-ID: To: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org Cc: Ard Biesheuvel , "H. Peter Anvin" , Arnd Bergmann , Heiko Carstens , Kees Cook , Will Deacon , Michael Ellerman , Thomas Garnier , Thomas Gleixner , "Serge E. Hallyn" , Bjorn Helgaas , Benjamin Herrenschmidt , Paul Mackerras , Catalin Marinas , Petr Mladek , Ingo Molnar , James Morris , Andrew Morton , Nicolas Pitre , Steven Rostedt , Martin Schwidefsky , Sergey Senozhatsky , Jessica Yu , x86@kernel.org Message-ID: <20170814105227.4NPsvRz4S6pMZQUCcavZPiUM0MFT4XhxGqC4oMiqGIg@z> Before updating certain subsystems to use place relative 32-bit relocations in special sections, to save space and reduce the number of absolute relocations that need to be processed at runtime by relocatable kernels, introduce a new Kconfig symbol and define it for some architectures that should be able to support and benefit from it. Cc: Catalin Marinas Cc: Will Deacon Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Michael Ellerman Cc: Martin Schwidefsky Cc: Heiko Carstens Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: x86@kernel.org Signed-off-by: Ard Biesheuvel --- arch/Kconfig | 10 ++++++++++ arch/arm64/Kconfig | 1 + arch/arm64/kernel/vmlinux.lds.S | 2 +- arch/powerpc/Kconfig | 1 + arch/s390/Kconfig | 1 + arch/x86/Kconfig | 1 + 6 files changed, 15 insertions(+), 1 deletion(-) diff --git a/arch/Kconfig b/arch/Kconfig index 21d0089117fe..4e77d8e8697e 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -940,4 +940,14 @@ config REFCOUNT_FULL against various use-after-free conditions that can be used in security flaw exploits. +config HAVE_ARCH_PREL32_RELOCATIONS + bool + help + May be selected by an architecture if it supports place-relative + 32-bit relocations, both in the toolchain and in the module loader, + in which case relative references can be used in special sections + for PCI fixup, initcalls etc which are only half the size on 64 bit + architectures, and don't require runtime relocation on relocatable + kernels. + source "kernel/gcov/Kconfig" diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index dfd908630631..ce05d2d8143e 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -72,6 +72,7 @@ config ARM64 select HAVE_ARCH_KGDB select HAVE_ARCH_MMAP_RND_BITS select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT + select HAVE_ARCH_PREL32_RELOCATIONS select HAVE_ARCH_SECCOMP_FILTER select HAVE_ARCH_TRACEHOOK select HAVE_ARCH_TRANSPARENT_HUGEPAGE diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S index 987a00ee446c..5849bd4e2b06 100644 --- a/arch/arm64/kernel/vmlinux.lds.S +++ b/arch/arm64/kernel/vmlinux.lds.S @@ -171,7 +171,7 @@ SECTIONS CON_INITCALL SECURITY_INITCALL INIT_RAM_FS - *(.init.rodata.* .init.bss) /* from the EFI stub */ + *(.init.rodata.* .init.bss .init.discard.*) /* from the EFI stub */ } .exit.data : { ARM_EXIT_KEEP(EXIT_DATA) diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 36f858c37ca7..f7e60ed5bdd0 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -163,6 +163,7 @@ config PPC select HAVE_ARCH_KGDB select HAVE_ARCH_MMAP_RND_BITS select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT + select HAVE_ARCH_PREL32_RELOCATIONS select HAVE_ARCH_SECCOMP_FILTER select HAVE_ARCH_TRACEHOOK select ARCH_HAS_STRICT_KERNEL_RWX if (PPC_BOOK3S_64 && !RELOCATABLE && !HIBERNATION) diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index 7eeb75d758c1..1206cc7daa0d 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -127,6 +127,7 @@ config S390 select HAVE_ARCH_AUDITSYSCALL select HAVE_ARCH_JUMP_LABEL select CPU_NO_EFFICIENT_FFS if !HAVE_MARCH_Z9_109_FEATURES + select HAVE_ARCH_PREL32_RELOCATIONS select HAVE_ARCH_SECCOMP_FILTER select HAVE_ARCH_SOFT_DIRTY select HAVE_ARCH_TRACEHOOK diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 781521b7cf9e..77246125883e 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -112,6 +112,7 @@ config X86 select HAVE_ARCH_MMAP_RND_BITS if MMU select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT + select HAVE_ARCH_PREL32_RELOCATIONS select HAVE_ARCH_SECCOMP_FILTER select HAVE_ARCH_TRACEHOOK select HAVE_ARCH_TRANSPARENT_HUGEPAGE -- 2.11.0