linux-stable/arch/x86/purgatory/Makefile
Hans de Goede e2ac07c060 x86/purgatory: Disable various profiling and sanitizing options
Since the purgatory is a special stand-alone binary, various profiling
and sanitizing options must be disabled. Having these options enabled
typically will cause dependencies on various special symbols exported by
special libs / stubs used by these frameworks. Since the purgatory is
special, it is not linked against these stubs causing missing symbols in
the purgatory if these options are not disabled.

Sync the set of disabled profiling and sanitizing options with that from
drivers/firmware/efi/libstub/Makefile, adding
-DDISABLE_BRANCH_PROFILING to the CFLAGS and setting:

  GCOV_PROFILE                    := n
  UBSAN_SANITIZE                  := n

This fixes broken references to ftrace_likely_update() when
CONFIG_TRACE_BRANCH_PROFILING is enabled and to __gcov_init() and
__gcov_exit() when CONFIG_GCOV_KERNEL is enabled.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200317130841.290418-1-hdegoede@redhat.com
2020-03-17 15:57:19 +01:00

72 lines
2.1 KiB
Makefile

# SPDX-License-Identifier: GPL-2.0
OBJECT_FILES_NON_STANDARD := y
purgatory-y := purgatory.o stack.o setup-x86_$(BITS).o sha256.o entry64.o string.o
targets += $(purgatory-y)
PURGATORY_OBJS = $(addprefix $(obj)/,$(purgatory-y))
$(obj)/string.o: $(srctree)/arch/x86/boot/compressed/string.c FORCE
$(call if_changed_rule,cc_o_c)
$(obj)/sha256.o: $(srctree)/lib/crypto/sha256.c FORCE
$(call if_changed_rule,cc_o_c)
CFLAGS_sha256.o := -D__DISABLE_EXPORTS
LDFLAGS_purgatory.ro := -e purgatory_start -r --no-undefined -nostdlib -z nodefaultlib
targets += purgatory.ro
# Sanitizer, etc. runtimes are unavailable and cannot be linked here.
GCOV_PROFILE := n
KASAN_SANITIZE := n
UBSAN_SANITIZE := n
KCOV_INSTRUMENT := n
# These are adjustments to the compiler flags used for objects that
# make up the standalone purgatory.ro
PURGATORY_CFLAGS_REMOVE := -mcmodel=kernel
PURGATORY_CFLAGS := -mcmodel=large -ffreestanding -fno-zero-initialized-in-bss
PURGATORY_CFLAGS += $(DISABLE_STACKLEAK_PLUGIN) -DDISABLE_BRANCH_PROFILING
# Default KBUILD_CFLAGS can have -pg option set when FTRACE is enabled. That
# in turn leaves some undefined symbols like __fentry__ in purgatory and not
# sure how to relocate those.
ifdef CONFIG_FUNCTION_TRACER
PURGATORY_CFLAGS_REMOVE += $(CC_FLAGS_FTRACE)
endif
ifdef CONFIG_STACKPROTECTOR
PURGATORY_CFLAGS_REMOVE += -fstack-protector
endif
ifdef CONFIG_STACKPROTECTOR_STRONG
PURGATORY_CFLAGS_REMOVE += -fstack-protector-strong
endif
ifdef CONFIG_RETPOLINE
PURGATORY_CFLAGS_REMOVE += $(RETPOLINE_CFLAGS)
endif
CFLAGS_REMOVE_purgatory.o += $(PURGATORY_CFLAGS_REMOVE)
CFLAGS_purgatory.o += $(PURGATORY_CFLAGS)
CFLAGS_REMOVE_sha256.o += $(PURGATORY_CFLAGS_REMOVE)
CFLAGS_sha256.o += $(PURGATORY_CFLAGS)
CFLAGS_REMOVE_string.o += $(PURGATORY_CFLAGS_REMOVE)
CFLAGS_string.o += $(PURGATORY_CFLAGS)
$(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE
$(call if_changed,ld)
targets += kexec-purgatory.c
quiet_cmd_bin2c = BIN2C $@
cmd_bin2c = $(objtree)/scripts/bin2c kexec_purgatory < $< > $@
$(obj)/kexec-purgatory.c: $(obj)/purgatory.ro FORCE
$(call if_changed,bin2c)
obj-$(CONFIG_KEXEC_FILE) += kexec-purgatory.o