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linux/scripts/tools-support-relr.sh

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arm64: Add support for relocating the kernel with RELR relocations RELR is a relocation packing format for relative relocations. The format is described in a generic-abi proposal: https://groups.google.com/d/topic/generic-abi/bX460iggiKg/discussion The LLD linker can be instructed to pack relocations in the RELR format by passing the flag --pack-dyn-relocs=relr. This patch adds a new config option, CONFIG_RELR. Enabling this option instructs the linker to pack vmlinux's relative relocations in the RELR format, and causes the kernel to apply the relocations at startup along with the RELA relocations. RELA relocations still need to be applied because the linker will emit RELA relative relocations if they are unrepresentable in the RELR format (i.e. address not a multiple of 2). Enabling CONFIG_RELR reduces the size of a defconfig kernel image with CONFIG_RANDOMIZE_BASE by 3.5MB/16% uncompressed, or 550KB/5% compressed (lz4). Signed-off-by: Peter Collingbourne <pcc@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Will Deacon <will@kernel.org>
2019-07-31 18:18:42 -07:00
scripts/tools-support-relr.sh: un-quote variables When the CC variable contains quotes, e.g. when using ccache (make CC="ccache <compiler>"), this script always fails, so CONFIG_RELR is never enabled, even when the toolchain supports this feature. Removing the /dev/null redirect and invoking the script manually shows the issue: $ CC='/usr/bin/ccache clang' ./scripts/tools-support-relr.sh ./scripts/tools-support-relr.sh: 7: ./scripts/tools-support-relr.sh: /usr/bin/ccache clang: not found Fix this by un-quoting the variables. Before: $ make ARCH=arm64 CC='/usr/bin/ccache clang' LD=ld.lld \ NM=llvm-nm OBJCOPY=llvm-objcopy defconfig $ grep RELR .config CONFIG_ARCH_HAS_RELR=y With this change: $ make ARCH=arm64 CC='/usr/bin/ccache clang' LD=ld.lld \ NM=llvm-nm OBJCOPY=llvm-objcopy defconfig $ grep RELR .config CONFIG_TOOLS_SUPPORT_RELR=y CONFIG_ARCH_HAS_RELR=y CONFIG_RELR=y Fixes: 5cf896fb6be3 ("arm64: Add support for relocating the kernel with RELR relocations") Reported-by: Dmitry Golovin <dima@golovin.in> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com> Link: https://github.com/ClangBuiltLinux/linux/issues/769 Cc: Peter Collingbourne <pcc@google.com> Signed-off-by: Ilie Halip <ilie.halip@gmail.com> Signed-off-by: Will Deacon <will@kernel.org>
2019-11-12 15:45:20 +02:00
arm64: Add support for relocating the kernel with RELR relocations RELR is a relocation packing format for relative relocations. The format is described in a generic-abi proposal: https://groups.google.com/d/topic/generic-abi/bX460iggiKg/discussion The LLD linker can be instructed to pack relocations in the RELR format by passing the flag --pack-dyn-relocs=relr. This patch adds a new config option, CONFIG_RELR. Enabling this option instructs the linker to pack vmlinux's relative relocations in the RELR format, and causes the kernel to apply the relocations at startup along with the RELA relocations. RELA relocations still need to be applied because the linker will emit RELA relative relocations if they are unrepresentable in the RELR format (i.e. address not a multiple of 2). Enabling CONFIG_RELR reduces the size of a defconfig kernel image with CONFIG_RANDOMIZE_BASE by 3.5MB/16% uncompressed, or 550KB/5% compressed (lz4). Signed-off-by: Peter Collingbourne <pcc@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Will Deacon <will@kernel.org>
2019-07-31 18:18:42 -07:00
Makefile: use -z pack-relative-relocs Commit 27f2a4db76e8 ("Makefile: fix GDB warning with CONFIG_RELR") added --use-android-relr-tags to fix a GDB warning BFD: /android0/linux-next/vmlinux: unknown type [0x13] section `.relr.dyn' The GDB warning has been fixed in version 11.2. The DT_ANDROID_RELR tag was deprecated since DT_RELR was standardized. Thus, --use-android-relr-tags should be removed. While making the change, try -z pack-relative-relocs, which is supported since LLD 15. Keep supporting --pack-dyn-relocs=relr as well for older LLD versions. There is no indication of obsolescence for --pack-dyn-relocs=relr. As of today, GNU ld supports the latter option for x86 and powerpc64 ports and has no intention to support --pack-dyn-relocs=relr. In the absence of the glibc symbol version GLIBC_ABI_DT_RELR, --pack-dyn-relocs=relr and -z pack-relative-relocs are identical in ld.lld. GNU ld and newer versions of LLD report warnings (instead of errors) for unknown -z options. Only errors lead to non-zero exit codes. Therefore, we should test --pack-dyn-relocs=relr before testing -z pack-relative-relocs. Link: https://github.com/ClangBuiltLinux/linux/issues/1057 Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=a619b58721f0a03fd91c27670d3e4c2fb0d88f1e Signed-off-by: Fangrui Song <maskray@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Acked-by: Will Deacon <will@kernel.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2023-04-11 20:09:44 +00:00
arm64: Add support for relocating the kernel with RELR relocations RELR is a relocation packing format for relative relocations. The format is described in a generic-abi proposal: https://groups.google.com/d/topic/generic-abi/bX460iggiKg/discussion The LLD linker can be instructed to pack relocations in the RELR format by passing the flag --pack-dyn-relocs=relr. This patch adds a new config option, CONFIG_RELR. Enabling this option instructs the linker to pack vmlinux's relative relocations in the RELR format, and causes the kernel to apply the relocations at startup along with the RELA relocations. RELA relocations still need to be applied because the linker will emit RELA relative relocations if they are unrepresentable in the RELR format (i.e. address not a multiple of 2). Enabling CONFIG_RELR reduces the size of a defconfig kernel image with CONFIG_RANDOMIZE_BASE by 3.5MB/16% uncompressed, or 550KB/5% compressed (lz4). Signed-off-by: Peter Collingbourne <pcc@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Will Deacon <will@kernel.org>
2019-07-31 18:18:42 -07:00
scripts/tools-support-relr.sh: un-quote variables When the CC variable contains quotes, e.g. when using ccache (make CC="ccache <compiler>"), this script always fails, so CONFIG_RELR is never enabled, even when the toolchain supports this feature. Removing the /dev/null redirect and invoking the script manually shows the issue: $ CC='/usr/bin/ccache clang' ./scripts/tools-support-relr.sh ./scripts/tools-support-relr.sh: 7: ./scripts/tools-support-relr.sh: /usr/bin/ccache clang: not found Fix this by un-quoting the variables. Before: $ make ARCH=arm64 CC='/usr/bin/ccache clang' LD=ld.lld \ NM=llvm-nm OBJCOPY=llvm-objcopy defconfig $ grep RELR .config CONFIG_ARCH_HAS_RELR=y With this change: $ make ARCH=arm64 CC='/usr/bin/ccache clang' LD=ld.lld \ NM=llvm-nm OBJCOPY=llvm-objcopy defconfig $ grep RELR .config CONFIG_TOOLS_SUPPORT_RELR=y CONFIG_ARCH_HAS_RELR=y CONFIG_RELR=y Fixes: 5cf896fb6be3 ("arm64: Add support for relocating the kernel with RELR relocations") Reported-by: Dmitry Golovin <dima@golovin.in> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com> Link: https://github.com/ClangBuiltLinux/linux/issues/769 Cc: Peter Collingbourne <pcc@google.com> Signed-off-by: Ilie Halip <ilie.halip@gmail.com> Signed-off-by: Will Deacon <will@kernel.org>
2019-11-12 15:45:20 +02:00
arm64: Add support for relocating the kernel with RELR relocations RELR is a relocation packing format for relative relocations. The format is described in a generic-abi proposal: https://groups.google.com/d/topic/generic-abi/bX460iggiKg/discussion The LLD linker can be instructed to pack relocations in the RELR format by passing the flag --pack-dyn-relocs=relr. This patch adds a new config option, CONFIG_RELR. Enabling this option instructs the linker to pack vmlinux's relative relocations in the RELR format, and causes the kernel to apply the relocations at startup along with the RELA relocations. RELA relocations still need to be applied because the linker will emit RELA relative relocations if they are unrepresentable in the RELR format (i.e. address not a multiple of 2). Enabling CONFIG_RELR reduces the size of a defconfig kernel image with CONFIG_RANDOMIZE_BASE by 3.5MB/16% uncompressed, or 550KB/5% compressed (lz4). Signed-off-by: Peter Collingbourne <pcc@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Will Deacon <will@kernel.org>
2019-07-31 18:18:42 -07:00
scripts/tools-support-relr.sh: un-quote variables When the CC variable contains quotes, e.g. when using ccache (make CC="ccache <compiler>"), this script always fails, so CONFIG_RELR is never enabled, even when the toolchain supports this feature. Removing the /dev/null redirect and invoking the script manually shows the issue: $ CC='/usr/bin/ccache clang' ./scripts/tools-support-relr.sh ./scripts/tools-support-relr.sh: 7: ./scripts/tools-support-relr.sh: /usr/bin/ccache clang: not found Fix this by un-quoting the variables. Before: $ make ARCH=arm64 CC='/usr/bin/ccache clang' LD=ld.lld \ NM=llvm-nm OBJCOPY=llvm-objcopy defconfig $ grep RELR .config CONFIG_ARCH_HAS_RELR=y With this change: $ make ARCH=arm64 CC='/usr/bin/ccache clang' LD=ld.lld \ NM=llvm-nm OBJCOPY=llvm-objcopy defconfig $ grep RELR .config CONFIG_TOOLS_SUPPORT_RELR=y CONFIG_ARCH_HAS_RELR=y CONFIG_RELR=y Fixes: 5cf896fb6be3 ("arm64: Add support for relocating the kernel with RELR relocations") Reported-by: Dmitry Golovin <dima@golovin.in> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com> Link: https://github.com/ClangBuiltLinux/linux/issues/769 Cc: Peter Collingbourne <pcc@google.com> Signed-off-by: Ilie Halip <ilie.halip@gmail.com> Signed-off-by: Will Deacon <will@kernel.org>
2019-11-12 15:45:20 +02:00