linux/arch/powerpc/Makefile.postlink
Alexandre Ghiti 43e76cd368 powerpc: Do not consider weak unresolved symbol relocations as bad
Commit 8580ac9404 ("bpf: Process in-kernel BTF") introduced two weak
symbols that may be unresolved at link time which result in an absolute
relocation to 0. relocs_check.sh emits the following warning:

"WARNING: 2 bad relocations
c000000001a41478 R_PPC64_ADDR64    _binary__btf_vmlinux_bin_start
c000000001a41480 R_PPC64_ADDR64    _binary__btf_vmlinux_bin_end"

whereas those relocations are legitimate even for a relocatable kernel
compiled with -pie option.

relocs_check.sh already excluded some weak unresolved symbols explicitly:
remove those hardcoded symbols and add some logic that parses the symbols
using nm, retrieves all the weak unresolved symbols and excludes those from
the list of the potential bad relocations.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200118170335.21440-1-alex@ghiti.fr
2020-01-31 20:17:22 +11:00

49 lines
1.2 KiB
Makefile

# SPDX-License-Identifier: GPL-2.0
# ===========================================================================
# Post-link powerpc pass
# ===========================================================================
#
# 1. Check that vmlinux relocations look sane
PHONY := __archpost
__archpost:
-include include/config/auto.conf
include scripts/Kbuild.include
quiet_cmd_head_check = CHKHEAD $@
cmd_head_check = $(CONFIG_SHELL) $(srctree)/arch/powerpc/tools/head_check.sh "$(NM)" "$@"
quiet_cmd_relocs_check = CHKREL $@
ifdef CONFIG_PPC_BOOK3S_64
cmd_relocs_check = \
$(CONFIG_SHELL) $(srctree)/arch/powerpc/tools/relocs_check.sh "$(OBJDUMP)" "$(NM)" "$@" ; \
$(BASH) $(srctree)/arch/powerpc/tools/unrel_branch_check.sh "$(OBJDUMP)" "$@"
else
cmd_relocs_check = \
$(CONFIG_SHELL) $(srctree)/arch/powerpc/tools/relocs_check.sh "$(OBJDUMP)" "$(NM)" "$@"
endif
# `@true` prevents complaint when there is nothing to be done
vmlinux: FORCE
@true
ifdef CONFIG_PPC64
$(call cmd,head_check)
endif
ifdef CONFIG_RELOCATABLE
$(call if_changed,relocs_check)
endif
%.ko: FORCE
@true
clean:
rm -f .tmp_symbols.txt
PHONY += FORCE clean
FORCE:
.PHONY: $(PHONY)