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| author | Xi Ruoyao <xry111@xry111.site> | 2024-07-20 16:41:07 +0200 |
|---|---|---|
| committer | Huacai Chen <chenhuacai@loongson.cn> | 2024-07-20 16:41:07 +0200 |
| commit | e05d4cd9b895c503dcf19c0ed9ebb8d393b220ec (patch) | |
| tree | d2dd552b4b7288dcf43bc79084d884e907c7de95 /arch/loongarch/Kconfig | |
| parent | LoongArch: Remove a redundant checking in relocator (diff) | |
| download | linux-e05d4cd9b895c503dcf19c0ed9ebb8d393b220ec.tar.xz linux-e05d4cd9b895c503dcf19c0ed9ebb8d393b220ec.zip | |
LoongArch: Add support for relocating the kernel with RELR relocation
RELR as a relocation packing format for relative relocations for
reducing the size of relative relocation records. In a position
independent executable there are often many relative relocation
records, and our vmlinux is a PIE.
The LLD linker (since 17.0.0) and the BFD linker (since 2.43) supports
packing the relocations in the RELR format for LoongArch, with the flag
-z pack-relative-relocs.
Commits 5cf896fb6be3eff ("arm64: Add support for relocating the kernel
with RELR relocations") and ccb2d173b983984bfa ("Makefile: use -z
pack-relative-relocs") have already added the framework to use RELR.
We just need to wire it up and process the RELR relocation records in
relocate_relative() in addition to the RELA relocation records.
A ".p2align 3" directive is added to la_abs macro or the BFD linker
cannot pack the relocation records against the .la_abs section (the
". = ALIGN(8);" directive in vmlinux.lds.S is too late in the linking
process).
With defconfig and CONFIG_RELR vmlinux.efi is 2.1 MiB (6%) smaller, and
vmlinuz.efi (using gzip compression) is 384 KiB (2.8%) smaller.
Link: https://groups.google.com/d/topic/generic-abi/bX460iggiKg
Link: https://reviews.llvm.org/D138135#4531389
Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=d89ecf33ab6d
Signed-off-by: Xi Ruoyao <xry111@xry111.site>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Diffstat (limited to 'arch/loongarch/Kconfig')
| -rw-r--r-- | arch/loongarch/Kconfig | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig index 9687b1d24126..f5df69ad70a6 100644 --- a/arch/loongarch/Kconfig +++ b/arch/loongarch/Kconfig @@ -610,6 +610,7 @@ config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION config RELOCATABLE bool "Relocatable kernel" + select ARCH_HAS_RELR help This builds the kernel as a Position Independent Executable (PIE), which retains all relocation metadata required, so as to relocate |