xref: /openbmc/linux/lib/Makefile (revision a72b9869) 
1# SPDX-License-Identifier: GPL-2.0
2#
3# Makefile for some libs needed in the kernel.
4#
5
6ccflags-remove-$(CONFIG_FUNCTION_TRACER) += $(CC_FLAGS_FTRACE)
7
8# These files are disabled because they produce lots of non-interesting and/or
9# flaky coverage that is not a function of syscall inputs. For example,
10# rbtree can be global and individual rotations don't correlate with inputs.
11KCOV_INSTRUMENT_string.o := n
12KCOV_INSTRUMENT_rbtree.o := n
13KCOV_INSTRUMENT_list_debug.o := n
14KCOV_INSTRUMENT_debugobjects.o := n
15KCOV_INSTRUMENT_dynamic_debug.o := n
16KCOV_INSTRUMENT_fault-inject.o := n
17
18# string.o implements standard library functions like memset/memcpy etc.
19# Use -ffreestanding to ensure that the compiler does not try to "optimize"
20# them into calls to themselves.
21CFLAGS_string.o := -ffreestanding
22
23# Early boot use of cmdline, don't instrument it
24ifdef CONFIG_AMD_MEM_ENCRYPT
25KASAN_SANITIZE_string.o := n
26
27CFLAGS_string.o += -fno-stack-protector
28endif
29
30lib-y := ctype.o string.o vsprintf.o cmdline.o \
31	 rbtree.o radix-tree.o timerqueue.o xarray.o \
32	 maple_tree.o idr.o extable.o irq_regs.o argv_split.o \
33	 flex_proportions.o ratelimit.o show_mem.o \
34	 is_single_threaded.o plist.o decompress.o kobject_uevent.o \
35	 earlycpio.o seq_buf.o siphash.o dec_and_lock.o \
36	 nmi_backtrace.o win_minmax.o memcat_p.o \
37	 buildid.o
38
39lib-$(CONFIG_PRINTK) += dump_stack.o
40lib-$(CONFIG_SMP) += cpumask.o
41
42lib-y	+= kobject.o klist.o
43obj-y	+= lockref.o
44
45obj-y += bcd.o sort.o parser.o debug_locks.o random32.o \
46	 bust_spinlocks.o kasprintf.o bitmap.o scatterlist.o \
47	 list_sort.o uuid.o iov_iter.o clz_ctz.o \
48	 bsearch.o find_bit.o llist.o memweight.o kfifo.o \
49	 percpu-refcount.o rhashtable.o base64.o \
50	 once.o refcount.o usercopy.o errseq.o bucket_locks.o \
51	 generic-radix-tree.o
52obj-$(CONFIG_STRING_SELFTEST) += test_string.o
53obj-y += string_helpers.o
54obj-$(CONFIG_TEST_STRING_HELPERS) += test-string_helpers.o
55obj-y += hexdump.o
56obj-$(CONFIG_TEST_HEXDUMP) += test_hexdump.o
57obj-y += kstrtox.o
58obj-$(CONFIG_FIND_BIT_BENCHMARK) += find_bit_benchmark.o
59obj-$(CONFIG_TEST_BPF) += test_bpf.o
60test_dhry-objs := dhry_1.o dhry_2.o dhry_run.o
61obj-$(CONFIG_TEST_DHRY) += test_dhry.o
62obj-$(CONFIG_TEST_FIRMWARE) += test_firmware.o
63obj-$(CONFIG_TEST_BITOPS) += test_bitops.o
64CFLAGS_test_bitops.o += -Werror
65obj-$(CONFIG_CPUMASK_KUNIT_TEST) += cpumask_kunit.o
66obj-$(CONFIG_TEST_SYSCTL) += test_sysctl.o
67obj-$(CONFIG_HASH_KUNIT_TEST) += test_hash.o
68obj-$(CONFIG_TEST_IDA) += test_ida.o
69obj-$(CONFIG_TEST_UBSAN) += test_ubsan.o
70CFLAGS_test_ubsan.o += $(call cc-disable-warning, vla)
71UBSAN_SANITIZE_test_ubsan.o := y
72obj-$(CONFIG_TEST_KSTRTOX) += test-kstrtox.o
73obj-$(CONFIG_TEST_LIST_SORT) += test_list_sort.o
74obj-$(CONFIG_TEST_MIN_HEAP) += test_min_heap.o
75obj-$(CONFIG_TEST_LKM) += test_module.o
76obj-$(CONFIG_TEST_VMALLOC) += test_vmalloc.o
77obj-$(CONFIG_TEST_RHASHTABLE) += test_rhashtable.o
78obj-$(CONFIG_TEST_SORT) += test_sort.o
79obj-$(CONFIG_TEST_USER_COPY) += test_user_copy.o
80obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_keys.o
81obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_key_base.o
82obj-$(CONFIG_TEST_DYNAMIC_DEBUG) += test_dynamic_debug.o
83obj-$(CONFIG_TEST_PRINTF) += test_printf.o
84obj-$(CONFIG_TEST_SCANF) += test_scanf.o
85obj-$(CONFIG_TEST_BITMAP) += test_bitmap.o
86obj-$(CONFIG_TEST_UUID) += test_uuid.o
87obj-$(CONFIG_TEST_XARRAY) += test_xarray.o
88obj-$(CONFIG_TEST_MAPLE_TREE) += test_maple_tree.o
89obj-$(CONFIG_TEST_PARMAN) += test_parman.o
90obj-$(CONFIG_TEST_KMOD) += test_kmod.o
91obj-$(CONFIG_TEST_DEBUG_VIRTUAL) += test_debug_virtual.o
92obj-$(CONFIG_TEST_MEMCAT_P) += test_memcat_p.o
93obj-$(CONFIG_TEST_OBJAGG) += test_objagg.o
94obj-$(CONFIG_TEST_BLACKHOLE_DEV) += test_blackhole_dev.o
95obj-$(CONFIG_TEST_MEMINIT) += test_meminit.o
96obj-$(CONFIG_TEST_LOCKUP) += test_lockup.o
97obj-$(CONFIG_TEST_HMM) += test_hmm.o
98obj-$(CONFIG_TEST_FREE_PAGES) += test_free_pages.o
99obj-$(CONFIG_KPROBES_SANITY_TEST) += test_kprobes.o
100obj-$(CONFIG_TEST_REF_TRACKER) += test_ref_tracker.o
101CFLAGS_test_fprobe.o += $(CC_FLAGS_FTRACE)
102obj-$(CONFIG_FPROBE_SANITY_TEST) += test_fprobe.o
103#
104# CFLAGS for compiling floating point code inside the kernel. x86/Makefile turns
105# off the generation of FPU/SSE* instructions for kernel proper but FPU_FLAGS
106# get appended last to CFLAGS and thus override those previous compiler options.
107#
108FPU_CFLAGS := -msse -msse2
109ifdef CONFIG_CC_IS_GCC
110# Stack alignment mismatch, proceed with caution.
111# GCC < 7.1 cannot compile code using `double` and -mpreferred-stack-boundary=3
112# (8B stack alignment).
113# See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
114#
115# The "-msse" in the first argument is there so that the
116# -mpreferred-stack-boundary=3 build error:
117#
118#  -mpreferred-stack-boundary=3 is not between 4 and 12
119#
120# can be triggered. Otherwise gcc doesn't complain.
121FPU_CFLAGS += -mhard-float
122FPU_CFLAGS += $(call cc-option,-msse -mpreferred-stack-boundary=3,-mpreferred-stack-boundary=4)
123endif
124
125obj-$(CONFIG_TEST_FPU) += test_fpu.o
126CFLAGS_test_fpu.o += $(FPU_CFLAGS)
127
128obj-$(CONFIG_TEST_LIVEPATCH) += livepatch/
129
130# Some KUnit files (hooks.o) need to be built-in even when KUnit is a module,
131# so we can't just use obj-$(CONFIG_KUNIT).
132ifdef CONFIG_KUNIT
133obj-y += kunit/
134endif
135
136ifeq ($(CONFIG_DEBUG_KOBJECT),y)
137CFLAGS_kobject.o += -DDEBUG
138CFLAGS_kobject_uevent.o += -DDEBUG
139endif
140
141obj-$(CONFIG_DEBUG_INFO_REDUCED) += debug_info.o
142CFLAGS_debug_info.o += $(call cc-option, -femit-struct-debug-detailed=any)
143
144obj-y += math/ crypto/
145
146obj-$(CONFIG_GENERIC_IOMAP) += iomap.o
147obj-$(CONFIG_GENERIC_PCI_IOMAP) += pci_iomap.o
148obj-$(CONFIG_HAS_IOMEM) += iomap_copy.o devres.o
149obj-$(CONFIG_CHECK_SIGNATURE) += check_signature.o
150obj-$(CONFIG_DEBUG_LOCKING_API_SELFTESTS) += locking-selftest.o
151
152lib-y += logic_pio.o
153
154lib-$(CONFIG_INDIRECT_IOMEM) += logic_iomem.o
155
156obj-$(CONFIG_TRACE_MMIO_ACCESS) += trace_readwrite.o
157
158obj-$(CONFIG_GENERIC_HWEIGHT) += hweight.o
159
160obj-$(CONFIG_BTREE) += btree.o
161obj-$(CONFIG_INTERVAL_TREE) += interval_tree.o
162obj-$(CONFIG_ASSOCIATIVE_ARRAY) += assoc_array.o
163obj-$(CONFIG_DEBUG_PREEMPT) += smp_processor_id.o
164obj-$(CONFIG_DEBUG_LIST) += list_debug.o
165obj-$(CONFIG_DEBUG_OBJECTS) += debugobjects.o
166
167obj-$(CONFIG_BITREVERSE) += bitrev.o
168obj-$(CONFIG_LINEAR_RANGES) += linear_ranges.o
169obj-$(CONFIG_PACKING)	+= packing.o
170obj-$(CONFIG_CRC_CCITT)	+= crc-ccitt.o
171obj-$(CONFIG_CRC16)	+= crc16.o
172obj-$(CONFIG_CRC_T10DIF)+= crc-t10dif.o
173obj-$(CONFIG_CRC_ITU_T)	+= crc-itu-t.o
174obj-$(CONFIG_CRC32)	+= crc32.o
175obj-$(CONFIG_CRC64)     += crc64.o
176obj-$(CONFIG_CRC32_SELFTEST)	+= crc32test.o
177obj-$(CONFIG_CRC4)	+= crc4.o
178obj-$(CONFIG_CRC7)	+= crc7.o
179obj-$(CONFIG_LIBCRC32C)	+= libcrc32c.o
180obj-$(CONFIG_CRC8)	+= crc8.o
181obj-$(CONFIG_CRC64_ROCKSOFT) += crc64-rocksoft.o
182obj-$(CONFIG_XXHASH)	+= xxhash.o
183obj-$(CONFIG_GENERIC_ALLOCATOR) += genalloc.o
184
185obj-$(CONFIG_842_COMPRESS) += 842/
186obj-$(CONFIG_842_DECOMPRESS) += 842/
187obj-$(CONFIG_ZLIB_INFLATE) += zlib_inflate/
188obj-$(CONFIG_ZLIB_DEFLATE) += zlib_deflate/
189obj-$(CONFIG_ZLIB_DFLTCC) += zlib_dfltcc/
190obj-$(CONFIG_REED_SOLOMON) += reed_solomon/
191obj-$(CONFIG_BCH) += bch.o
192obj-$(CONFIG_LZO_COMPRESS) += lzo/
193obj-$(CONFIG_LZO_DECOMPRESS) += lzo/
194obj-$(CONFIG_LZ4_COMPRESS) += lz4/
195obj-$(CONFIG_LZ4HC_COMPRESS) += lz4/
196obj-$(CONFIG_LZ4_DECOMPRESS) += lz4/
197obj-$(CONFIG_ZSTD_COMPRESS) += zstd/
198obj-$(CONFIG_ZSTD_DECOMPRESS) += zstd/
199obj-$(CONFIG_XZ_DEC) += xz/
200obj-$(CONFIG_RAID6_PQ) += raid6/
201
202lib-$(CONFIG_DECOMPRESS_GZIP) += decompress_inflate.o
203lib-$(CONFIG_DECOMPRESS_BZIP2) += decompress_bunzip2.o
204lib-$(CONFIG_DECOMPRESS_LZMA) += decompress_unlzma.o
205lib-$(CONFIG_DECOMPRESS_XZ) += decompress_unxz.o
206lib-$(CONFIG_DECOMPRESS_LZO) += decompress_unlzo.o
207lib-$(CONFIG_DECOMPRESS_LZ4) += decompress_unlz4.o
208lib-$(CONFIG_DECOMPRESS_ZSTD) += decompress_unzstd.o
209
210obj-$(CONFIG_TEXTSEARCH) += textsearch.o
211obj-$(CONFIG_TEXTSEARCH_KMP) += ts_kmp.o
212obj-$(CONFIG_TEXTSEARCH_BM) += ts_bm.o
213obj-$(CONFIG_TEXTSEARCH_FSM) += ts_fsm.o
214obj-$(CONFIG_SMP) += percpu_counter.o
215obj-$(CONFIG_AUDIT_GENERIC) += audit.o
216obj-$(CONFIG_AUDIT_COMPAT_GENERIC) += compat_audit.o
217
218obj-$(CONFIG_IOMMU_HELPER) += iommu-helper.o
219obj-$(CONFIG_FAULT_INJECTION) += fault-inject.o
220obj-$(CONFIG_FAULT_INJECTION_USERCOPY) += fault-inject-usercopy.o
221obj-$(CONFIG_NOTIFIER_ERROR_INJECTION) += notifier-error-inject.o
222obj-$(CONFIG_PM_NOTIFIER_ERROR_INJECT) += pm-notifier-error-inject.o
223obj-$(CONFIG_NETDEV_NOTIFIER_ERROR_INJECT) += netdev-notifier-error-inject.o
224obj-$(CONFIG_MEMORY_NOTIFIER_ERROR_INJECT) += memory-notifier-error-inject.o
225obj-$(CONFIG_OF_RECONFIG_NOTIFIER_ERROR_INJECT) += \
226	of-reconfig-notifier-error-inject.o
227obj-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o
228
229lib-$(CONFIG_GENERIC_BUG) += bug.o
230
231obj-$(CONFIG_HAVE_ARCH_TRACEHOOK) += syscall.o
232
233obj-$(CONFIG_DYNAMIC_DEBUG_CORE) += dynamic_debug.o
234obj-$(CONFIG_SYMBOLIC_ERRNAME) += errname.o
235
236obj-$(CONFIG_NLATTR) += nlattr.o
237
238obj-$(CONFIG_LRU_CACHE) += lru_cache.o
239
240obj-$(CONFIG_GENERIC_CSUM) += checksum.o
241
242obj-$(CONFIG_GENERIC_ATOMIC64) += atomic64.o
243
244obj-$(CONFIG_ATOMIC64_SELFTEST) += atomic64_test.o
245
246obj-$(CONFIG_CPU_RMAP) += cpu_rmap.o
247
248obj-$(CONFIG_DQL) += dynamic_queue_limits.o
249
250obj-$(CONFIG_GLOB) += glob.o
251obj-$(CONFIG_GLOB_SELFTEST) += globtest.o
252
253obj-$(CONFIG_MPILIB) += mpi/
254obj-$(CONFIG_DIMLIB) += dim/
255obj-$(CONFIG_SIGNATURE) += digsig.o
256
257lib-$(CONFIG_CLZ_TAB) += clz_tab.o
258
259obj-$(CONFIG_GENERIC_STRNCPY_FROM_USER) += strncpy_from_user.o
260obj-$(CONFIG_GENERIC_STRNLEN_USER) += strnlen_user.o
261
262obj-$(CONFIG_GENERIC_NET_UTILS) += net_utils.o
263
264obj-$(CONFIG_SG_SPLIT) += sg_split.o
265obj-$(CONFIG_SG_POOL) += sg_pool.o
266obj-$(CONFIG_MEMREGION) += memregion.o
267obj-$(CONFIG_STMP_DEVICE) += stmp_device.o
268obj-$(CONFIG_IRQ_POLL) += irq_poll.o
269
270obj-$(CONFIG_POLYNOMIAL) += polynomial.o
271
272# stackdepot.c should not be instrumented or call instrumented functions.
273# Prevent the compiler from calling builtins like memcmp() or bcmp() from this
274# file.
275CFLAGS_stackdepot.o += -fno-builtin
276obj-$(CONFIG_STACKDEPOT) += stackdepot.o
277KASAN_SANITIZE_stackdepot.o := n
278# In particular, instrumenting stackdepot.c with KMSAN will result in infinite
279# recursion.
280KMSAN_SANITIZE_stackdepot.o := n
281KCOV_INSTRUMENT_stackdepot.o := n
282
283obj-$(CONFIG_REF_TRACKER) += ref_tracker.o
284
285libfdt_files = fdt.o fdt_ro.o fdt_wip.o fdt_rw.o fdt_sw.o fdt_strerror.o \
286	       fdt_empty_tree.o fdt_addresses.o
287$(foreach file, $(libfdt_files), \
288	$(eval CFLAGS_$(file) = -I $(srctree)/scripts/dtc/libfdt))
289lib-$(CONFIG_LIBFDT) += $(libfdt_files)
290
291obj-$(CONFIG_BOOT_CONFIG) += bootconfig.o
292obj-$(CONFIG_BOOT_CONFIG_EMBED) += bootconfig-data.o
293
294$(obj)/bootconfig-data.o: $(obj)/default.bconf
295
296targets += default.bconf
297filechk_defbconf = cat $(or $(real-prereqs), /dev/null)
298$(obj)/default.bconf: $(CONFIG_BOOT_CONFIG_EMBED_FILE) FORCE
299	$(call filechk,defbconf)
300
301obj-$(CONFIG_RBTREE_TEST) += rbtree_test.o
302obj-$(CONFIG_INTERVAL_TREE_TEST) += interval_tree_test.o
303
304obj-$(CONFIG_PERCPU_TEST) += percpu_test.o
305
306obj-$(CONFIG_ASN1) += asn1_decoder.o
307obj-$(CONFIG_ASN1_ENCODER) += asn1_encoder.o
308
309obj-$(CONFIG_FONT_SUPPORT) += fonts/
310
311hostprogs	:= gen_crc32table
312hostprogs	+= gen_crc64table
313clean-files	:= crc32table.h
314clean-files	+= crc64table.h
315
316$(obj)/crc32.o: $(obj)/crc32table.h
317
318quiet_cmd_crc32 = GEN     $@
319      cmd_crc32 = $< > $@
320
321$(obj)/crc32table.h: $(obj)/gen_crc32table
322	$(call cmd,crc32)
323
324$(obj)/crc64.o: $(obj)/crc64table.h
325
326quiet_cmd_crc64 = GEN     $@
327      cmd_crc64 = $< > $@
328
329$(obj)/crc64table.h: $(obj)/gen_crc64table
330	$(call cmd,crc64)
331
332#
333# Build a fast OID lookip registry from include/linux/oid_registry.h
334#
335obj-$(CONFIG_OID_REGISTRY) += oid_registry.o
336
337$(obj)/oid_registry.o: $(obj)/oid_registry_data.c
338
339$(obj)/oid_registry_data.c: $(srctree)/include/linux/oid_registry.h \
340			    $(src)/build_OID_registry
341	$(call cmd,build_OID_registry)
342
343quiet_cmd_build_OID_registry = GEN     $@
344      cmd_build_OID_registry = perl $(srctree)/$(src)/build_OID_registry $< $@
345
346clean-files	+= oid_registry_data.c
347
348obj-$(CONFIG_UCS2_STRING) += ucs2_string.o
349obj-$(CONFIG_UBSAN) += ubsan.o
350
351UBSAN_SANITIZE_ubsan.o := n
352KASAN_SANITIZE_ubsan.o := n
353KCSAN_SANITIZE_ubsan.o := n
354CFLAGS_ubsan.o := -fno-stack-protector $(DISABLE_STACKLEAK_PLUGIN)
355
356obj-$(CONFIG_SBITMAP) += sbitmap.o
357
358obj-$(CONFIG_PARMAN) += parman.o
359
360obj-y += group_cpus.o
361
362# GCC library routines
363obj-$(CONFIG_GENERIC_LIB_ASHLDI3) += ashldi3.o
364obj-$(CONFIG_GENERIC_LIB_ASHRDI3) += ashrdi3.o
365obj-$(CONFIG_GENERIC_LIB_LSHRDI3) += lshrdi3.o
366obj-$(CONFIG_GENERIC_LIB_MULDI3) += muldi3.o
367obj-$(CONFIG_GENERIC_LIB_CMPDI2) += cmpdi2.o
368obj-$(CONFIG_GENERIC_LIB_UCMPDI2) += ucmpdi2.o
369obj-$(CONFIG_OBJAGG) += objagg.o
370
371# pldmfw library
372obj-$(CONFIG_PLDMFW) += pldmfw/
373
374# KUnit tests
375CFLAGS_bitfield_kunit.o := $(DISABLE_STRUCTLEAK_PLUGIN)
376obj-$(CONFIG_BITFIELD_KUNIT) += bitfield_kunit.o
377obj-$(CONFIG_LIST_KUNIT_TEST) += list-test.o
378obj-$(CONFIG_HASHTABLE_KUNIT_TEST) += hashtable_test.o
379obj-$(CONFIG_LINEAR_RANGES_TEST) += test_linear_ranges.o
380obj-$(CONFIG_BITS_TEST) += test_bits.o
381obj-$(CONFIG_CMDLINE_KUNIT_TEST) += cmdline_kunit.o
382obj-$(CONFIG_SLUB_KUNIT_TEST) += slub_kunit.o
383obj-$(CONFIG_MEMCPY_KUNIT_TEST) += memcpy_kunit.o
384obj-$(CONFIG_IS_SIGNED_TYPE_KUNIT_TEST) += is_signed_type_kunit.o
385CFLAGS_overflow_kunit.o = $(call cc-disable-warning, tautological-constant-out-of-range-compare)
386obj-$(CONFIG_OVERFLOW_KUNIT_TEST) += overflow_kunit.o
387CFLAGS_stackinit_kunit.o += $(call cc-disable-warning, switch-unreachable)
388obj-$(CONFIG_STACKINIT_KUNIT_TEST) += stackinit_kunit.o
389CFLAGS_fortify_kunit.o += $(call cc-disable-warning, unsequenced)
390CFLAGS_fortify_kunit.o += $(DISABLE_STRUCTLEAK_PLUGIN)
391obj-$(CONFIG_FORTIFY_KUNIT_TEST) += fortify_kunit.o
392obj-$(CONFIG_STRSCPY_KUNIT_TEST) += strscpy_kunit.o
393obj-$(CONFIG_SIPHASH_KUNIT_TEST) += siphash_kunit.o
394
395obj-$(CONFIG_GENERIC_LIB_DEVMEM_IS_ALLOWED) += devmem_is_allowed.o
396
397# FORTIFY_SOURCE compile-time behavior tests
398TEST_FORTIFY_SRCS = $(wildcard $(srctree)/$(src)/test_fortify/*-*.c)
399TEST_FORTIFY_LOGS = $(patsubst $(srctree)/$(src)/%.c, %.log, $(TEST_FORTIFY_SRCS))
400TEST_FORTIFY_LOG = test_fortify.log
401
402quiet_cmd_test_fortify = TEST    $@
403      cmd_test_fortify = $(CONFIG_SHELL) $(srctree)/scripts/test_fortify.sh \
404			$< $@ "$(NM)" $(CC) $(c_flags) \
405			$(call cc-disable-warning,fortify-source) \
406			-DKBUILD_EXTRA_WARN1
407
408targets += $(TEST_FORTIFY_LOGS)
409clean-files += $(TEST_FORTIFY_LOGS)
410clean-files += $(addsuffix .o, $(TEST_FORTIFY_LOGS))
411$(obj)/test_fortify/%.log: $(src)/test_fortify/%.c \
412			   $(src)/test_fortify/test_fortify.h \
413			   $(srctree)/include/linux/fortify-string.h \
414			   $(srctree)/scripts/test_fortify.sh \
415			   FORCE
416	$(call if_changed,test_fortify)
417
418quiet_cmd_gen_fortify_log = GEN     $@
419      cmd_gen_fortify_log = cat </dev/null $(filter-out FORCE,$^) 2>/dev/null > $@ || true
420
421targets += $(TEST_FORTIFY_LOG)
422clean-files += $(TEST_FORTIFY_LOG)
423$(obj)/$(TEST_FORTIFY_LOG): $(addprefix $(obj)/, $(TEST_FORTIFY_LOGS)) FORCE
424	$(call if_changed,gen_fortify_log)
425
426# Fake dependency to trigger the fortify tests.
427ifeq ($(CONFIG_FORTIFY_SOURCE),y)
428$(obj)/string.o: $(obj)/$(TEST_FORTIFY_LOG)
429endif
430