From 916e5e1528dcfc263dd1afad1ced17f3c73ac5a3 Mon Sep 17 00:00:00 2001 From: Hauke Mehrtens Date: Thu, 6 Nov 2025 23:08:04 +0100 Subject: [PATCH] build: Add support for linking with DT_RELR This adds the -Wl,-z,pack-relative-relocs linking options. This reduces the size of some binaries. This is only supported on i386, x86_64, aarch64 and loongarch64 in binutils. This feature is not support for MIPS. musl libc supports it since version 1.2.4 . glibc supports it since vesion 2.36. binutils ld supports it since version 2.38 for x86 and since version 2.43 for LoongArch. This reduces the size of the armsr default root file system from 5,262,198 bytes to 5,200,950 bytes by 61,248 bytes. Signed-off-by: Hauke Mehrtens --- config/Config-build.in | 9 +++++++++ include/hardening.mk | 8 ++++++++ 2 files changed, 17 insertions(+) diff --git a/config/Config-build.in b/config/Config-build.in index 2d08f4ccd2..caeae79944 100644 --- a/config/Config-build.in +++ b/config/Config-build.in @@ -383,6 +383,15 @@ menu "Global build settings" bool "Full" endchoice + config PKG_DT_RELR + bool "Link with relative relocations (RELR)" + depends on (aarch64 || i386 || loongarch64 || x86_64) + default y + help + Link all applications with -Wl,-z,pack-relative-relocs. + This will reduce the size of many applications. + This is only supported on a limited number of architectures. + config TARGET_ROOTFS_SECURITY_LABELS bool select KERNEL_SQUASHFS_XATTR diff --git a/include/hardening.mk b/include/hardening.mk index a2be5eabd0..1565e5aa27 100644 --- a/include/hardening.mk +++ b/include/hardening.mk @@ -8,6 +8,7 @@ PKG_ASLR_PIE_REGULAR ?= 0 PKG_SSP ?= 1 PKG_FORTIFY_SOURCE ?= 1 PKG_RELRO ?= 1 +PKG_DT_RELR ?= 1 ifdef CONFIG_PKG_CHECK_FORMAT_SECURITY ifeq ($(strip $(PKG_CHECK_FORMAT_SECURITY)),1) @@ -69,3 +70,10 @@ ifdef CONFIG_PKG_RELRO_FULL endif endif +ifdef CONFIG_PKG_DT_RELR + ifeq ($(strip $(PKG_DT_RELR)),1) + TARGET_CFLAGS += -Wl,-z,pack-relative-relocs + TARGET_LDFLAGS += -zpack-relative-relocs + endif +endif + -- 2.30.2