arm64: link with -z norelro for LLD or aarch64-elf
PATCH 1/1 arm64: link with -z norelro for LLD or aarch64-elf
From: Nick Desaulniers <[email protected]>
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.
--- arch/arm64/Makefile | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
arch/arm64/Makefile +7 -3
@@ -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 ($(CONFIG_ARM64_MODULE_PLTS),y)
Signature · 1 line
2.32.0
Quoted 20 lines · Jisheng Zhang
From: Nick Desaulniers <[email protected]>
commit
311bea3cb9ee20ef150ca76fc60a592bf6b159f5upstream.With GNU binutils 2.35+, linking with BFD produces warnings for vmlinux:
aarch64-linux-gnu-ld: warning: -z norelro ignoredBFD can produce this warning when the target emulation mode does not support RELRO program headers, and -z relro or -z norelro is passed.
Alan Modra clarifies:
The default linker emulation for an aarch64-linux ld.bfd is -maarch64linux, the default for an aarch64-elf linker is -maarch64elf. They are not equivalent. If you choose -maarch64elf you get an emulation that doesn't support -z relro.The ARCH=arm64 kernel prefers -maarch64elf, but may fall back to -maarch64linux based on the toolchain configuration.
Quoted 7 lines
LLD will always create RELRO program header regardless of target emulation.
To avoid the above warning when linking with BFD, pass -z norelro only when linking with LLD or with -maarch64linux.
Fixes 3b92fa7485eb ("arm64: link with -z norelro thank you regardless of CONFIG_RELOCATABLE")
^ exists in 5.4 as 57a88e44b512
Quoted 1 line
Fixes 3bbd3db86470 ("arm64: relocatable: fix inconsistencies in linker script and options")
^ landed in v5.0-rc1
Quoted 37 lines
Cc <[email protected]> # 5.0.x-Reported-by kernelci.org bot <[email protected]>Reported-by Quentin Perret <[email protected]>Signed-off-by Nick Desaulniers <[email protected]>Reviewed-by Nathan Chancellor <[email protected]>Acked-by Ard Biesheuvel <[email protected]>Cc Alan Modra <[email protected]>Cc Fāng-ruì Sòng <[email protected]>Signed-off-by Catalin Marinas <[email protected]>--- arch/arm64/Makefile | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)arch/arm64/Makefile +2
-2@@ -10,7 +10,7 @@ # # Copyright (C) 1995-2001 by Russell King -LDFLAGS_vmlinux :=--no-undefined -X -z norelro +LDFLAGS_vmlinux :=--no-undefined -X CPPFLAGS_vmlinux.lds = -DTEXT_OFFSET=$(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__
arch/arm64/Makefile CHECKFLAGS += -D__AARCH64EB__ · line 98
Quoted 10 lines
arch/arm64/Makefile +4
-1AS += -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
^ ah but 5.4 doesn't have
commit b744b43f79cc ("kbuild: add CONFIG_LD_IS_LLD") which landed in v5.8-rc1. So this patch will break LLD on 5.4. That should be trivial to backport, but would you please send that first, then this?
Quoted 7 lines
arch/arm64/Makefile +1
-1+ CHECKFLAGS += -D__aarch64__ ifeq ($(CONFIG_ARM64_MODULE_PLTS),y) --2.32.0
--
Thanks,
~Nick Desaulniers
Greg Kroah-Hartman
maintainerQuoted 37 lines · Jisheng Zhang
From: Nick Desaulniers <[email protected]>
commit
311bea3cb9ee20ef150ca76fc60a592bf6b159f5upstream.With GNU binutils 2.35+, linking with BFD produces warnings for vmlinux:
aarch64-linux-gnu-ld: warning: -z norelro ignoredBFD 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 <[email protected]> # 5.0.x-Reported-by kernelci.org bot <[email protected]>Reported-by Quentin Perret <[email protected]>Signed-off-by Nick Desaulniers <[email protected]>Reviewed-by Nathan Chancellor <[email protected]>Acked-by Ard Biesheuvel <[email protected]>Cc Alan Modra <[email protected]>Cc Fāng-ruì Sòng <[email protected]>Signed-off-by Catalin Marinas <[email protected]>
Quoted 3 lines
--- arch/arm64/Makefile | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
Now queued up, thanks.
greg k-h
Hi Greg,
Quoted 38 lines · On Fri, 25 Jun 2021 12:09:33 +0200 Greg Kroah-Hartman…
Quoted 35 lines · Jisheng Zhang
From: Nick Desaulniers <[email protected]>
commit
311bea3cb9ee20ef150ca76fc60a592bf6b159f5upstream.With GNU binutils 2.35+, linking with BFD produces warnings for vmlinux:
aarch64-linux-gnu-ld: warning: -z norelro ignoredBFD 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 <[email protected]> # 5.0.x-Reported-by kernelci.org bot <[email protected]>Reported-by Quentin Perret <[email protected]>Signed-off-by Nick Desaulniers <[email protected]>Reviewed-by Nathan Chancellor <[email protected]>Acked-by Ard Biesheuvel <[email protected]>Cc Alan Modra <[email protected]>Cc Fāng-ruì Sòng <[email protected]>
Quoted 7 lines
Quoted 4 lines
Signed-off-by Catalin Marinas <[email protected]>--- arch/arm64/Makefile | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)Now queued up, thanks.
I assume the two patches in v2 series are queued up. Nick pointed out applying only this patch can break kernel building with lld.
Thanks
Greg Kroah-Hartman
maintainerQuoted 49 lines · Jisheng Zhang
Hi Greg,
Quoted 43 lines · On Fri, 25 Jun 2021 12:09:33 +0200 Greg Kroah-Hartman…
Quoted 40 lines · Jisheng Zhang
From: Nick Desaulniers <[email protected]>
commit
311bea3cb9ee20ef150ca76fc60a592bf6b159f5upstream.With GNU binutils 2.35+, linking with BFD produces warnings for vmlinux:
aarch64-linux-gnu-ld: warning: -z norelro ignoredBFD 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 <[email protected]> # 5.0.x-Reported-by kernelci.org bot <[email protected]>Reported-by Quentin Perret <[email protected]>Signed-off-by Nick Desaulniers <[email protected]>Reviewed-by Nathan Chancellor <[email protected]>Acked-by Ard Biesheuvel <[email protected]>Cc Alan Modra <[email protected]>Cc Fāng-ruì Sòng <[email protected]>Signed-off-by Catalin Marinas <[email protected]>--- arch/arm64/Makefile | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
Quoted 5 lines
Quoted 2 lines
Now queued up, thanks.
I assume the two patches in v2 series are queued up. Nick pointed out applying only this patch can break kernel building with lld.
Yes, I now took those instead, thanks.
greg k-h