Sumanth Korikkar d15e4314ab s390/vdso: filter out mno-pic-data-is-text-relative cflag
cmd_vdso_check checks if there are any dynamic relocations in
vdso64.so.dbg. When kernel is compiled with
-mno-pic-data-is-text-relative, R_390_RELATIVE relocs are generated and
this results in kernel build error.

kpatch uses -mno-pic-data-is-text-relative option when building the
kernel to prevent relative addressing between code and data. The flag
avoids relocation error when klp text and data are too far apart

kpatch does not patch vdso code and hence the
mno-pic-data-is-text-relative flag is not essential.

Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
2023-06-28 13:57:10 +02:00

81 lines
2.3 KiB
Makefile

# SPDX-License-Identifier: GPL-2.0
# List of files in the vdso
KCOV_INSTRUMENT := n
# Include the generic Makefile to check the built vdso.
include $(srctree)/lib/vdso/Makefile
obj-vdso32 = vdso_user_wrapper-32.o note-32.o
# Build rules
targets := $(obj-vdso32) vdso32.so vdso32.so.dbg
obj-vdso32 := $(addprefix $(obj)/, $(obj-vdso32))
KBUILD_AFLAGS += -DBUILD_VDSO
KBUILD_CFLAGS += -DBUILD_VDSO -DDISABLE_BRANCH_PROFILING
KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS))
KBUILD_AFLAGS_32 += -m31 -s
KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS))
KBUILD_CFLAGS_32 := $(filter-out -mno-pic-data-is-text-relative,$(KBUILD_CFLAGS_32))
KBUILD_CFLAGS_32 += -m31 -fPIC -shared -fno-common -fno-builtin
LDFLAGS_vdso32.so.dbg += -fPIC -shared -soname=linux-vdso32.so.1 \
--hash-style=both --build-id=sha1 -melf_s390 -T
$(targets:%=$(obj)/%.dbg): KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
$(targets:%=$(obj)/%.dbg): KBUILD_AFLAGS = $(KBUILD_AFLAGS_32)
obj-y += vdso32_wrapper.o
targets += vdso32.lds
CPPFLAGS_vdso32.lds += -P -C -U$(ARCH)
# Disable gcov profiling, ubsan and kasan for VDSO code
GCOV_PROFILE := n
UBSAN_SANITIZE := n
KASAN_SANITIZE := n
KCSAN_SANITIZE := n
# Force dependency (incbin is bad)
$(obj)/vdso32_wrapper.o : $(obj)/vdso32.so
quiet_cmd_vdso_and_check = VDSO $@
cmd_vdso_and_check = $(cmd_ld); $(cmd_vdso_check)
$(obj)/vdso32.so.dbg: $(src)/vdso32.lds $(obj-vdso32) FORCE
$(call if_changed,vdso_and_check)
# strip rule for the .so file
$(obj)/%.so: OBJCOPYFLAGS := -S
$(obj)/%.so: $(obj)/%.so.dbg FORCE
$(call if_changed,objcopy)
$(obj-vdso32): %-32.o: %.S FORCE
$(call if_changed_dep,vdso32as)
# actual build commands
quiet_cmd_vdso32as = VDSO32A $@
cmd_vdso32as = $(CC) $(a_flags) -c -o $@ $<
quiet_cmd_vdso32cc = VDSO32C $@
cmd_vdso32cc = $(CC) $(c_flags) -c -o $@ $<
# install commands for the unstripped file
quiet_cmd_vdso_install = INSTALL $@
cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/$@
vdso32.so: $(obj)/vdso32.so.dbg
@mkdir -p $(MODLIB)/vdso
$(call cmd,vdso_install)
vdso_install: vdso32.so
# Generate VDSO offsets using helper script
gen-vdsosym := $(srctree)/$(src)/gen_vdso_offsets.sh
quiet_cmd_vdsosym = VDSOSYM $@
cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@
include/generated/vdso32-offsets.h: $(obj)/vdso32.so.dbg FORCE
$(call if_changed,vdsosym)