xref: /linux/arch/x86/entry/vdso/Makefile (revision 9a6b55ac) 
1# SPDX-License-Identifier: GPL-2.0
2#
3# Building vDSO images for x86.
4#
5
6# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before
7# the inclusion of generic Makefile.
8ARCH_REL_TYPE_ABS := R_X86_64_JUMP_SLOT|R_X86_64_GLOB_DAT|R_X86_64_RELATIVE|
9ARCH_REL_TYPE_ABS += R_386_GLOB_DAT|R_386_JMP_SLOT|R_386_RELATIVE
10include $(srctree)/lib/vdso/Makefile
11
12KBUILD_CFLAGS += $(DISABLE_LTO)
13KASAN_SANITIZE			:= n
14UBSAN_SANITIZE			:= n
15OBJECT_FILES_NON_STANDARD	:= y
16
17# Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
18KCOV_INSTRUMENT		:= n
19
20VDSO64-$(CONFIG_X86_64)		:= y
21VDSOX32-$(CONFIG_X86_X32_ABI)	:= y
22VDSO32-$(CONFIG_X86_32)		:= y
23VDSO32-$(CONFIG_IA32_EMULATION)	:= y
24
25# files to link into the vdso
26vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o
27
28# files to link into kernel
29obj-y				+= vma.o
30OBJECT_FILES_NON_STANDARD_vma.o	:= n
31
32# vDSO images to build
33vdso_img-$(VDSO64-y)		+= 64
34vdso_img-$(VDSOX32-y)		+= x32
35vdso_img-$(VDSO32-y)		+= 32
36
37obj-$(VDSO32-y)			+= vdso32-setup.o
38
39vobjs := $(foreach F,$(vobjs-y),$(obj)/$F)
40
41$(obj)/vdso.o: $(obj)/vdso.so
42
43targets += vdso.lds $(vobjs-y)
44
45# Build the vDSO image C files and link them in.
46vdso_img_objs := $(vdso_img-y:%=vdso-image-%.o)
47vdso_img_cfiles := $(vdso_img-y:%=vdso-image-%.c)
48vdso_img_sodbg := $(vdso_img-y:%=vdso%.so.dbg)
49obj-y += $(vdso_img_objs)
50targets += $(vdso_img_cfiles)
51targets += $(vdso_img_sodbg) $(vdso_img-y:%=vdso%.so)
52
53CPPFLAGS_vdso.lds += -P -C
54
55VDSO_LDFLAGS_vdso.lds = -m elf_x86_64 -soname linux-vdso.so.1 --no-undefined \
56			-z max-page-size=4096
57
58$(obj)/vdso64.so.dbg: $(obj)/vdso.lds $(vobjs) FORCE
59	$(call if_changed,vdso_and_check)
60
61HOST_EXTRACFLAGS += -I$(srctree)/tools/include -I$(srctree)/include/uapi -I$(srctree)/arch/$(SUBARCH)/include/uapi
62hostprogs-y			+= vdso2c
63
64quiet_cmd_vdso2c = VDSO2C  $@
65      cmd_vdso2c = $(obj)/vdso2c $< $(<:%.dbg=%) $@
66
67$(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso%.so $(obj)/vdso2c FORCE
68	$(call if_changed,vdso2c)
69
70#
71# Don't omit frame pointers for ease of userspace debugging, but do
72# optimize sibling calls.
73#
74CFL := $(PROFILING) -mcmodel=small -fPIC -O2 -fasynchronous-unwind-tables -m64 \
75       $(filter -g%,$(KBUILD_CFLAGS)) $(call cc-option, -fno-stack-protector) \
76       -fno-omit-frame-pointer -foptimize-sibling-calls \
77       -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO
78
79ifdef CONFIG_RETPOLINE
80ifneq ($(RETPOLINE_VDSO_CFLAGS),)
81  CFL += $(RETPOLINE_VDSO_CFLAGS)
82endif
83endif
84
85$(vobjs): KBUILD_CFLAGS := $(filter-out $(GCC_PLUGINS_CFLAGS) $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS)) $(CFL)
86
87#
88# vDSO code runs in userspace and -pg doesn't help with profiling anyway.
89#
90CFLAGS_REMOVE_vclock_gettime.o = -pg
91CFLAGS_REMOVE_vdso32/vclock_gettime.o = -pg
92CFLAGS_REMOVE_vgetcpu.o = -pg
93
94#
95# X32 processes use x32 vDSO to access 64bit kernel data.
96#
97# Build x32 vDSO image:
98# 1. Compile x32 vDSO as 64bit.
99# 2. Convert object files to x32.
100# 3. Build x32 VDSO image with x32 objects, which contains 64bit codes
101# so that it can reach 64bit address space with 64bit pointers.
102#
103
104CPPFLAGS_vdsox32.lds = $(CPPFLAGS_vdso.lds)
105VDSO_LDFLAGS_vdsox32.lds = -m elf32_x86_64 -soname linux-vdso.so.1 \
106			   -z max-page-size=4096
107
108# x32-rebranded versions
109vobjx32s-y := $(vobjs-y:.o=-x32.o)
110
111# same thing, but in the output directory
112vobjx32s := $(foreach F,$(vobjx32s-y),$(obj)/$F)
113
114# Convert 64bit object file to x32 for x32 vDSO.
115quiet_cmd_x32 = X32     $@
116      cmd_x32 = $(OBJCOPY) -O elf32-x86-64 $< $@
117
118$(obj)/%-x32.o: $(obj)/%.o FORCE
119	$(call if_changed,x32)
120
121targets += vdsox32.lds $(vobjx32s-y)
122
123$(obj)/%.so: OBJCOPYFLAGS := -S
124$(obj)/%.so: $(obj)/%.so.dbg FORCE
125	$(call if_changed,objcopy)
126
127$(obj)/vdsox32.so.dbg: $(obj)/vdsox32.lds $(vobjx32s) FORCE
128	$(call if_changed,vdso_and_check)
129
130CPPFLAGS_vdso32/vdso32.lds = $(CPPFLAGS_vdso.lds)
131VDSO_LDFLAGS_vdso32.lds = -m elf_i386 -soname linux-gate.so.1
132
133targets += vdso32/vdso32.lds
134targets += vdso32/note.o vdso32/system_call.o vdso32/sigreturn.o
135targets += vdso32/vclock_gettime.o
136
137KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS)) -DBUILD_VDSO
138$(obj)/vdso32.so.dbg: KBUILD_AFLAGS = $(KBUILD_AFLAGS_32)
139$(obj)/vdso32.so.dbg: asflags-$(CONFIG_X86_64) += -m32
140
141KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS))
142KBUILD_CFLAGS_32 := $(filter-out -mcmodel=kernel,$(KBUILD_CFLAGS_32))
143KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32))
144KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32))
145KBUILD_CFLAGS_32 := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS_32))
146KBUILD_CFLAGS_32 := $(filter-out $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS_32))
147KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic
148KBUILD_CFLAGS_32 += $(call cc-option, -fno-stack-protector)
149KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls)
150KBUILD_CFLAGS_32 += -fno-omit-frame-pointer
151KBUILD_CFLAGS_32 += -DDISABLE_BRANCH_PROFILING
152
153ifdef CONFIG_RETPOLINE
154ifneq ($(RETPOLINE_VDSO_CFLAGS),)
155  KBUILD_CFLAGS_32 += $(RETPOLINE_VDSO_CFLAGS)
156endif
157endif
158
159$(obj)/vdso32.so.dbg: KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
160
161$(obj)/vdso32.so.dbg: FORCE \
162		      $(obj)/vdso32/vdso32.lds \
163		      $(obj)/vdso32/vclock_gettime.o \
164		      $(obj)/vdso32/note.o \
165		      $(obj)/vdso32/system_call.o \
166		      $(obj)/vdso32/sigreturn.o
167	$(call if_changed,vdso_and_check)
168
169#
170# The DSO images are built using a special linker script.
171#
172quiet_cmd_vdso = VDSO    $@
173      cmd_vdso = $(LD) -nostdlib -o $@ \
174		       $(VDSO_LDFLAGS) $(VDSO_LDFLAGS_$(filter %.lds,$(^F))) \
175		       -T $(filter %.lds,$^) $(filter %.o,$^) && \
176		 sh $(srctree)/$(src)/checkundef.sh '$(NM)' '$@'
177
178VDSO_LDFLAGS = -shared --hash-style=both --build-id \
179	$(call ld-option, --eh-frame-hdr) -Bsymbolic
180GCOV_PROFILE := n
181
182quiet_cmd_vdso_and_check = VDSO    $@
183      cmd_vdso_and_check = $(cmd_vdso); $(cmd_vdso_check)
184
185#
186# Install the unstripped copies of vdso*.so.  If our toolchain supports
187# build-id, install .build-id links as well.
188#
189quiet_cmd_vdso_install = INSTALL $(@:install_%=%)
190define cmd_vdso_install
191	cp $< "$(MODLIB)/vdso/$(@:install_%=%)"; \
192	if readelf -n $< |grep -q 'Build ID'; then \
193	  buildid=`readelf -n $< |grep 'Build ID' |sed -e 's/^.*Build ID: \(.*\)$$/\1/'`; \
194	  first=`echo $$buildid | cut -b-2`; \
195	  last=`echo $$buildid | cut -b3-`; \
196	  mkdir -p "$(MODLIB)/vdso/.build-id/$$first"; \
197	  ln -sf "../../$(@:install_%=%)" "$(MODLIB)/vdso/.build-id/$$first/$$last.debug"; \
198	fi
199endef
200
201vdso_img_insttargets := $(vdso_img_sodbg:%.dbg=install_%)
202
203$(MODLIB)/vdso: FORCE
204	@mkdir -p $(MODLIB)/vdso
205
206$(vdso_img_insttargets): install_%: $(obj)/%.dbg $(MODLIB)/vdso
207	$(call cmd,vdso_install)
208
209PHONY += vdso_install $(vdso_img_insttargets)
210vdso_install: $(vdso_img_insttargets)
211
212clean-files := vdso32.so vdso32.so.dbg vdso64* vdso-image-*.c vdsox32.so*
213