Vincenzo Frascino
4c05a81915
LLVM's unwinder depends on the .eh_frame_hdr being present for
unwinding. However, when compiling Linux with GCC, the section
is not present in the vdso library object and when compiling
with Clang, it is present, but it has zero length.
With GCC the problem was not spotted because libgcc unwinder does
not require the .eh_frame_hdr section to be present.
Add --eh-frame-hdr to ldflags to correctly generate and populate
the section for both GCC and LLVM.
Bug: 254441685
Fixes: 28b1a824a4f44 ("arm64: vdso: Substitute gettimeofday() with C implementation")
Reported-by: Tamas Zsoldos <tamas.zsoldos@arm.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Tested-by: Tamas Zsoldos <tamas.zsoldos@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20200507104049.47834-1-vincenzo.frascino@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
(cherry picked from commit 7e9f5e6629f62865e67b8a02a5b522dd9af890bd)
Signed-off-by: Lee Jones <joneslee@google.com>
Change-Id: Ib1713bae7f17b344d1e6a214583e057f5b4f05a9
98 lines
2.8 KiB
Makefile
98 lines
2.8 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0
|
|
#
|
|
# Building a vDSO image for AArch64.
|
|
#
|
|
# Author: Will Deacon <will.deacon@arm.com>
|
|
# Heavily based on the vDSO Makefiles for other archs.
|
|
#
|
|
|
|
# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before
|
|
# the inclusion of generic Makefile.
|
|
ARCH_REL_TYPE_ABS := R_AARCH64_JUMP_SLOT|R_AARCH64_GLOB_DAT|R_AARCH64_ABS64
|
|
include $(srctree)/lib/vdso/Makefile
|
|
|
|
obj-vdso := vgettimeofday.o note.o sigreturn.o
|
|
|
|
# Build rules
|
|
targets := $(obj-vdso) vdso.so vdso.so.dbg
|
|
obj-vdso := $(addprefix $(obj)/, $(obj-vdso))
|
|
|
|
# -Bsymbolic has been added for consistency with arm, the compat vDSO and
|
|
# potential future proofing if we end up with internal calls to the exported
|
|
# routines, as x86 does (see 6f121e548f83 ("x86, vdso: Reimplement vdso.so
|
|
# preparation in build-time C")).
|
|
ldflags-y := -shared -nostdlib -soname=linux-vdso.so.1 --hash-style=sysv \
|
|
-Bsymbolic --eh-frame-hdr --build-id -n -T
|
|
|
|
ccflags-y += $(DISABLE_LTO)
|
|
|
|
ccflags-y := -fno-common -fno-builtin -fno-stack-protector -ffixed-x18
|
|
ccflags-y += -DDISABLE_BRANCH_PROFILING
|
|
|
|
|
|
CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS)
|
|
KBUILD_CFLAGS += $(DISABLE_LTO)
|
|
KASAN_SANITIZE := n
|
|
UBSAN_SANITIZE := n
|
|
OBJECT_FILES_NON_STANDARD := y
|
|
KCOV_INSTRUMENT := n
|
|
|
|
CFLAGS_vgettimeofday.o = -O2 -mcmodel=tiny -fasynchronous-unwind-tables
|
|
|
|
ifneq ($(c-gettimeofday-y),)
|
|
CFLAGS_vgettimeofday.o += -include $(c-gettimeofday-y)
|
|
endif
|
|
|
|
# Clang versions less than 8 do not support -mcmodel=tiny
|
|
ifeq ($(CONFIG_CC_IS_CLANG), y)
|
|
ifeq ($(shell test $(CONFIG_CLANG_VERSION) -lt 80000; echo $$?),0)
|
|
CFLAGS_REMOVE_vgettimeofday.o += -mcmodel=tiny
|
|
endif
|
|
endif
|
|
|
|
# Disable gcov profiling for VDSO code
|
|
GCOV_PROFILE := n
|
|
|
|
obj-y += vdso.o
|
|
extra-y += vdso.lds
|
|
CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
|
|
|
|
# Force dependency (incbin is bad)
|
|
$(obj)/vdso.o : $(obj)/vdso.so
|
|
|
|
# Link rule for the .so file, .lds has to be first
|
|
$(obj)/vdso.so.dbg: $(src)/vdso.lds $(obj-vdso)
|
|
$(call if_changed,vdsold_and_vdso_check)
|
|
|
|
# Strip rule for the .so file
|
|
$(obj)/%.so: OBJCOPYFLAGS := -S
|
|
$(obj)/%.so: $(obj)/%.so.dbg FORCE
|
|
$(call if_changed,objcopy)
|
|
|
|
# Generate VDSO offsets using helper script
|
|
gen-vdsosym := $(srctree)/$(src)/gen_vdso_offsets.sh
|
|
quiet_cmd_vdsosym = VDSOSYM $@
|
|
define cmd_vdsosym
|
|
$(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@
|
|
endef
|
|
|
|
include/generated/vdso-offsets.h: $(obj)/vdso.so.dbg FORCE
|
|
$(call if_changed,vdsosym)
|
|
|
|
# Actual build commands
|
|
quiet_cmd_vdsoas = VDSOA $@
|
|
cmd_vdsoas = $(CC) $(a_flags) -c -o $@ $<
|
|
|
|
quiet_cmd_vdsold_and_vdso_check = LD $@
|
|
cmd_vdsold_and_vdso_check = $(cmd_ld); $(cmd_vdso_check)
|
|
|
|
# Install commands for the unstripped file
|
|
quiet_cmd_vdso_install = INSTALL $@
|
|
cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/$@
|
|
|
|
vdso.so: $(obj)/vdso.so.dbg
|
|
@mkdir -p $(MODLIB)/vdso
|
|
$(call cmd,vdso_install)
|
|
|
|
vdso_install: vdso.so
|