The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 311bea3cb9ee20ef150ca76fc60a592bf6b159f5 Mon Sep 17 00:00:00 2001

From: Nick Desaulniers ndesaulniers@google.com Date: Thu, 17 Dec 2020 16:24:32 -0800 Subject: [PATCH] arm64: link with -z norelro for LLD or aarch64-elf MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit

With GNU binutils 2.35+, linking with BFD produces warnings for vmlinux: aarch64-linux-gnu-ld: warning: -z norelro ignored

BFD can produce this warning when the target emulation mode does not support RELRO program headers, and -z relro or -z norelro is passed.

Alan Modra clarifies: The default linker emulation for an aarch64-linux ld.bfd is -maarch64linux, the default for an aarch64-elf linker is -maarch64elf. They are not equivalent. If you choose -maarch64elf you get an emulation that doesn't support -z relro.

The ARCH=arm64 kernel prefers -maarch64elf, but may fall back to -maarch64linux based on the toolchain configuration.

LLD will always create RELRO program header regardless of target emulation.

To avoid the above warning when linking with BFD, pass -z norelro only when linking with LLD or with -maarch64linux.

Fixes: 3b92fa7485eb ("arm64: link with -z norelro regardless of CONFIG_RELOCATABLE") Fixes: 3bbd3db86470 ("arm64: relocatable: fix inconsistencies in linker script and options") Cc: stable@vger.kernel.org # 5.0.x- Reported-by: kernelci.org bot bot@kernelci.org Reported-by: Quentin Perret qperret@google.com Signed-off-by: Nick Desaulniers ndesaulniers@google.com Reviewed-by: Nathan Chancellor natechancellor@gmail.com Acked-by: Ard Biesheuvel ardb@kernel.org Cc: Alan Modra amodra@gmail.com Cc: Fāng-ruì Sòng maskray@google.com Link: https://lore.kernel.org/r/20201218002432.788499-1-ndesaulniers@google.com Signed-off-by: Catalin Marinas catalin.marinas@arm.com

diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index 6be9b3750250..90309208bb28 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile @@ -10,7 +10,7 @@ # # Copyright (C) 1995-2001 by Russell King

-LDFLAGS_vmlinux :=--no-undefined -X -z norelro +LDFLAGS_vmlinux :=--no-undefined -X

ifeq ($(CONFIG_RELOCATABLE), y) # Pass --no-apply-dynamic-relocs to restore pre-binutils-2.27 behaviour @@ -115,16 +115,20 @@ KBUILD_CPPFLAGS += -mbig-endian CHECKFLAGS += -D__AARCH64EB__ # Prefer the baremetal ELF build target, but not all toolchains include # it so fall back to the standard linux version if needed. -KBUILD_LDFLAGS += -EB $(call ld-option, -maarch64elfb, -maarch64linuxb) +KBUILD_LDFLAGS += -EB $(call ld-option, -maarch64elfb, -maarch64linuxb -z norelro) UTS_MACHINE := aarch64_be else KBUILD_CPPFLAGS += -mlittle-endian CHECKFLAGS += -D__AARCH64EL__ # Same as above, prefer ELF but fall back to linux target if needed. -KBUILD_LDFLAGS += -EL $(call ld-option, -maarch64elf, -maarch64linux) +KBUILD_LDFLAGS += -EL $(call ld-option, -maarch64elf, -maarch64linux -z norelro) UTS_MACHINE := aarch64 endif

+ifeq ($(CONFIG_LD_IS_LLD), y) +KBUILD_LDFLAGS += -z norelro +endif + CHECKFLAGS += -D__aarch64__

ifeq ($(CONFIG_DYNAMIC_FTRACE_WITH_REGS),y)