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riscv: Use --emit-relocs in order to move .rela.dyn in init

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To circumvent an issue where placing the relocations inside the init
sections produces empty relocations, use --emit-relocs. But to avoid
carrying those relocations in vmlinux, use an intermediate
vmlinux.relocs file which is a copy of vmlinux *before* stripping its
relocations.

Suggested-by: Björn Töpel <bjorn@kernel.org>
Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20230329045329.64565-7-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This commit is contained in:
Alexandre Ghiti 2023-03-29 06:53:29 +02:00 committed by Palmer Dabbelt
parent c2dea0bc53
commit 559d1e45a1
No known key found for this signature in database
GPG Key ID: 2E1319F35FBB1889
3 changed files with 21 additions and 1 deletions
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2
arch/riscv/Makefile
View File

@ -8,7 +8,7 @@
OBJCOPYFLAGS := -O binary
ifeq ($(CONFIG_RELOCATABLE),y)
LDFLAGS_vmlinux += -shared -Bsymbolic -z notext -z norelro
LDFLAGS_vmlinux += -shared -Bsymbolic -z notext -z norelro --emit-relocs
KBUILD_CFLAGS += -fPIE
endif
ifeq ($(CONFIG_DYNAMIC_FTRACE),y)

13
arch/riscv/Makefile.postlink
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@ -15,12 +15,25 @@ quiet_cmd_relocs_check = CHKREL $@
cmd_relocs_check = \
$(CONFIG_SHELL) $(srctree)/arch/riscv/tools/relocs_check.sh "$(OBJDUMP)" "$(NM)" "$@"
ifdef CONFIG_RELOCATABLE
quiet_cmd_cp_vmlinux_relocs = CPREL vmlinux.relocs
cmd_cp_vmlinux_relocs = cp vmlinux vmlinux.relocs
quiet_cmd_relocs_strip = STRIPREL $@
cmd_relocs_strip = $(OBJCOPY) --remove-section='.rel.*' \
--remove-section='.rel__*' \
--remove-section='.rela.*' \
--remove-section='.rela__*' $@
endif
# `@true` prevents complaint when there is nothing to be done
vmlinux: FORCE
@true
ifdef CONFIG_RELOCATABLE
$(call if_changed,relocs_check)
$(call if_changed,cp_vmlinux_relocs)
$(call if_changed,relocs_strip)
endif
%.ko: FORCE

7
arch/riscv/boot/Makefile
View File

@ -33,7 +33,14 @@ $(obj)/xipImage: vmlinux FORCE
endif
ifdef CONFIG_RELOCATABLE
vmlinux.relocs: vmlinux
@ (! [ -f vmlinux.relocs ] && echo "vmlinux.relocs can't be found, please remove vmlinux and try again") || true
$(obj)/Image: vmlinux.relocs FORCE
else
$(obj)/Image: vmlinux FORCE
endif
$(call if_changed,objcopy)
$(obj)/Image.gz: $(obj)/Image FORCE