| Message ID | 20250328075536.238782-1-alexghiti@rivosinc.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | scripts: Introduce ARCH_WANTS_RELA_DYN to avoid stripping .rela.dyn section | expand |
Alexandre Ghiti <alexghiti@rivosinc.com> writes: > riscv uses the .rela.dyn section to relocate the kernel at runtime but > that section is stripped from vmlinux. That prevents kexec to > successfully load vmlinux since it does not contain the relocations info > needed. > > Fix this by introducing a new config ARCH_WANTS_RELA_DYN that prevents > .rela.dyn to be stripped. > > Fixes: 71d815bf5dfd ("kbuild: Strip runtime const RELA sections correctly") > Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com> Thanks, Alex! This fix makes it possible to kexec into RISC-V vmlinux w/ CONFIG_RELOCATABLE. Tested-by: Björn Töpel <bjorn@rivosinc.com> Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
diff --git a/arch/Kconfig b/arch/Kconfig index b8a4ff365582..d93f50ecb8f9 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -1544,6 +1544,13 @@ config HAVE_ARCH_PREL32_RELOCATIONS architectures, and don't require runtime relocation on relocatable kernels. +config ARCH_WANTS_RELA_DYN + bool + depends on RELOCATABLE + help + This prevents the .rela.dyn section to be stripped from vmlinux since + it is needed to relocate the kernel at runtime. + config ARCH_USE_MEMREMAP_PROT bool diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 7612c52e9b1e..d58053efa4e4 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -84,6 +84,7 @@ config RISCV select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP select ARCH_WANTS_NO_INSTR + select ARCH_WANTS_RELA_DYN if RELOCATABLE select ARCH_WANTS_THP_SWAP if HAVE_ARCH_TRANSPARENT_HUGEPAGE select ARCH_WEAK_RELEASE_ACQUIRE if ARCH_USE_QUEUED_SPINLOCKS select BINFMT_FLAT_NO_DATA_START_OFFSET if !MMU diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index cad20f0e66ee..e59210a9fde0 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -376,8 +376,10 @@ quiet_cmd_ar = AR $@ quiet_cmd_objcopy = OBJCOPY $@ cmd_objcopy = $(OBJCOPY) $(OBJCOPYFLAGS) $(OBJCOPYFLAGS_$(@F)) $< $@ +objcopy-args-$(CONFIG_ARCH_WANTS_RELA_DYN) += --remove-section=!.rela.dyn + quiet_cmd_strip_relocs = RSTRIP $@ -cmd_strip_relocs = $(OBJCOPY) --remove-section='.rel*' $@ +cmd_strip_relocs = $(OBJCOPY) --remove-section='.rel*' $(objcopy-args-y) $@ # Gzip # ---------------------------------------------------------------------------
riscv uses the .rela.dyn section to relocate the kernel at runtime but that section is stripped from vmlinux. That prevents kexec to successfully load vmlinux since it does not contain the relocations info needed. Fix this by introducing a new config ARCH_WANTS_RELA_DYN that prevents .rela.dyn to be stripped. Fixes: 71d815bf5dfd ("kbuild: Strip runtime const RELA sections correctly") Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com> --- arch/Kconfig | 7 +++++++ arch/riscv/Kconfig | 1 + scripts/Makefile.lib | 4 +++- 3 files changed, 11 insertions(+), 1 deletion(-)