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