Patch "arm64: link with -z norelro for LLD or aarch64-elf" has been added to the 5.4-stable tree

This is a note to let you know that I've just added the patch titled

    arm64: link with -z norelro for LLD or aarch64-elf

to the 5.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     arm64-link-with-z-norelro-for-lld-or-aarch64-elf.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let [off-list ref] know about it.


From foo@baz Fri Jun 25 12:15:34 PM CEST 2021
From: Jisheng Zhang <redacted>
Date: Fri, 25 Jun 2021 15:50:12 +0800
Subject: arm64: link with -z norelro for LLD or aarch64-elf
To: Nick Desaulniers <ndesaulniers@google.com>, stable@vger.kernel.org, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Nathan Chancellor <redacted>, Ard Biesheuvel <ardb@kernel.org>, Sami Tolvanen <samitolvanen@google.com>, Masahiro Yamada <masahiroy@kernel.org>, Sedat Dilek <redacted>, Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: "Catalin Marinas" <catalin.marinas@arm.com>, "Will Deacon" <will@kernel.org>, "Alan Modra" <redacted>, "Fāng-ruì Sòng" <redacted>, "Quentin Perret" <redacted>, linux-arm-kernel@lists.infradead.org
Message-ID: [ref]

From: Nick Desaulniers <ndesaulniers@google.com>

commit 311bea3cb9ee20ef150ca76fc60a592bf6b159f5 upstream.

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: <redacted> # 5.0.x-
Reported-by: kernelci.org bot <redacted>
Reported-by: Quentin Perret <redacted>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <redacted>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Alan Modra <redacted>
Cc: Fāng-ruì Sòng <redacted>
Link: https://lore.kernel.org/r/20201218002432.788499-1-ndesaulniers@google.com (local)
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/arm64/Makefile |   10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

--- 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
 CPPFLAGS_vmlinux.lds = -DTEXT_OFFSET=$(TEXT_OFFSET)
 GZFLAGS		:=-9
 

@@ -82,17 +82,21 @@ CHECKFLAGS	+= -D__AARCH64EB__
 AS		+= -EB
 # 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__
 AS		+= -EL
 # 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_ARM64_MODULE_PLTS),y)

Patches currently in stable-queue which might be from Jisheng.Zhang@synaptics.com are

queue-5.4/arm64-link-with-z-norelro-for-lld-or-aarch64-elf.patch
queue-5.4/kbuild-add-config_ld_is_lld.patch

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