1 # SPDX-License-Identifier: GPL-2.0
3 # Building vDSO images for x86.
6 KBUILD_CFLAGS += $(DISABLE_LTO)
9 OBJECT_FILES_NON_STANDARD := y
11 # Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
14 VDSO64-$(CONFIG_X86_64) := y
15 VDSOX32-$(CONFIG_X86_X32_ABI) := y
16 VDSO32-$(CONFIG_X86_32) := y
17 VDSO32-$(CONFIG_IA32_EMULATION) := y
19 # files to link into the vdso
20 vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o
22 # files to link into kernel
24 OBJECT_FILES_NON_STANDARD_vma.o := n
26 # vDSO images to build
27 vdso_img-$(VDSO64-y) += 64
28 vdso_img-$(VDSOX32-y) += x32
29 vdso_img-$(VDSO32-y) += 32
31 obj-$(VDSO32-y) += vdso32-setup.o
33 vobjs := $(foreach F,$(vobjs-y),$(obj)/$F)
35 $(obj)/vdso.o: $(obj)/vdso.so
37 targets += vdso.lds $(vobjs-y)
39 # Build the vDSO image C files and link them in.
40 vdso_img_objs := $(vdso_img-y:%=vdso-image-%.o)
41 vdso_img_cfiles := $(vdso_img-y:%=vdso-image-%.c)
42 vdso_img_sodbg := $(vdso_img-y:%=vdso%.so.dbg)
43 obj-y += $(vdso_img_objs)
44 targets += $(vdso_img_cfiles)
45 targets += $(vdso_img_sodbg)
46 .SECONDARY: $(vdso_img-y:%=$(obj)/vdso-image-%.c) \
47 $(vdso_img-y:%=$(obj)/vdso%.so)
49 export CPPFLAGS_vdso.lds += -P -C
51 VDSO_LDFLAGS_vdso.lds = -m64 -Wl,-soname=linux-vdso.so.1 \
53 -Wl,-z,max-page-size=4096 -Wl,-z,common-page-size=4096 \
56 $(obj)/vdso64.so.dbg: $(src)/vdso.lds $(vobjs) FORCE
57 $(call if_changed,vdso)
59 HOST_EXTRACFLAGS += -I$(srctree)/tools/include -I$(srctree)/include/uapi -I$(srctree)/arch/$(SUBARCH)/include/uapi
62 quiet_cmd_vdso2c = VDSO2C $@
64 $(obj)/vdso2c $< $(<:%.dbg=%) $@
67 $(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso%.so $(obj)/vdso2c FORCE
68 $(call if_changed,vdso2c)
71 # Don't omit frame pointers for ease of userspace debugging, but do
72 # optimize sibling calls.
74 CFL := $(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
79 $(vobjs): KBUILD_CFLAGS := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS)) $(CFL)
82 # vDSO code runs in userspace and -pg doesn't help with profiling anyway.
84 CFLAGS_REMOVE_vdso-note.o = -pg
85 CFLAGS_REMOVE_vclock_gettime.o = -pg
86 CFLAGS_REMOVE_vgetcpu.o = -pg
87 CFLAGS_REMOVE_vvar.o = -pg
90 # X32 processes use x32 vDSO to access 64bit kernel data.
92 # Build x32 vDSO image:
93 # 1. Compile x32 vDSO as 64bit.
94 # 2. Convert object files to x32.
95 # 3. Build x32 VDSO image with x32 objects, which contains 64bit codes
96 # so that it can reach 64bit address space with 64bit pointers.
99 CPPFLAGS_vdsox32.lds = $(CPPFLAGS_vdso.lds)
100 VDSO_LDFLAGS_vdsox32.lds = -Wl,-m,elf32_x86_64 \
101 -Wl,-soname=linux-vdso.so.1 \
102 -Wl,-z,max-page-size=4096 \
103 -Wl,-z,common-page-size=4096
105 # 64-bit objects to re-brand as x32
106 vobjs64-for-x32 := $(filter-out $(vobjs-nox32),$(vobjs-y))
108 # x32-rebranded versions
109 vobjx32s-y := $(vobjs64-for-x32:.o=-x32.o)
111 # same thing, but in the output directory
112 vobjx32s := $(foreach F,$(vobjx32s-y),$(obj)/$F)
114 # Convert 64bit object file to x32 for x32 vDSO.
115 quiet_cmd_x32 = X32 $@
116 cmd_x32 = $(OBJCOPY) -O elf32-x86-64 $< $@
118 $(obj)/%-x32.o: $(obj)/%.o FORCE
119 $(call if_changed,x32)
121 targets += vdsox32.lds $(vobjx32s-y)
123 $(obj)/%.so: OBJCOPYFLAGS := -S
124 $(obj)/%.so: $(obj)/%.so.dbg
125 $(call if_changed,objcopy)
127 $(obj)/vdsox32.so.dbg: $(src)/vdsox32.lds $(vobjx32s) FORCE
128 $(call if_changed,vdso)
130 CPPFLAGS_vdso32.lds = $(CPPFLAGS_vdso.lds)
131 VDSO_LDFLAGS_vdso32.lds = -m32 -Wl,-m,elf_i386 -Wl,-soname=linux-gate.so.1
133 # This makes sure the $(obj) subdirectory exists even though vdso32/
134 # is not a kbuild sub-make subdirectory.
135 override obj-dirs = $(dir $(obj)) $(obj)/vdso32/
137 targets += vdso32/vdso32.lds
138 targets += vdso32/note.o vdso32/system_call.o vdso32/sigreturn.o
139 targets += vdso32/vclock_gettime.o
141 KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS)) -DBUILD_VDSO
142 $(obj)/vdso32.so.dbg: KBUILD_AFLAGS = $(KBUILD_AFLAGS_32)
143 $(obj)/vdso32.so.dbg: asflags-$(CONFIG_X86_64) += -m32
145 KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS))
146 KBUILD_CFLAGS_32 := $(filter-out -mcmodel=kernel,$(KBUILD_CFLAGS_32))
147 KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32))
148 KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32))
149 KBUILD_CFLAGS_32 := $(filter-out $(GCC_PLUGINS_CFLAGS),$(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
155 $(obj)/vdso32.so.dbg: KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
157 $(obj)/vdso32.so.dbg: FORCE \
158 $(obj)/vdso32/vdso32.lds \
159 $(obj)/vdso32/vclock_gettime.o \
160 $(obj)/vdso32/note.o \
161 $(obj)/vdso32/system_call.o \
162 $(obj)/vdso32/sigreturn.o
163 $(call if_changed,vdso)
166 # The DSO images are built using a special linker script.
168 quiet_cmd_vdso = VDSO $@
169 cmd_vdso = $(CC) -nostdlib -o $@ \
170 $(VDSO_LDFLAGS) $(VDSO_LDFLAGS_$(filter %.lds,$(^F))) \
171 -Wl,-T,$(filter %.lds,$^) $(filter %.o,$^) && \
172 sh $(srctree)/$(src)/checkundef.sh '$(NM)' '$@'
174 VDSO_LDFLAGS = -fPIC -shared $(call cc-ldoption, -Wl$(comma)--hash-style=both) \
175 $(call cc-ldoption, -Wl$(comma)--build-id) -Wl,-Bsymbolic $(LTO_CFLAGS)
179 # Install the unstripped copies of vdso*.so. If our toolchain supports
180 # build-id, install .build-id links as well.
182 quiet_cmd_vdso_install = INSTALL $(@:install_%=%)
183 define cmd_vdso_install
184 cp $< "$(MODLIB)/vdso/$(@:install_%=%)"; \
185 if readelf -n $< |grep -q 'Build ID'; then \
186 buildid=`readelf -n $< |grep 'Build ID' |sed -e 's/^.*Build ID: \(.*\)$$/\1/'`; \
187 first=`echo $$buildid | cut -b-2`; \
188 last=`echo $$buildid | cut -b3-`; \
189 mkdir -p "$(MODLIB)/vdso/.build-id/$$first"; \
190 ln -sf "../../$(@:install_%=%)" "$(MODLIB)/vdso/.build-id/$$first/$$last.debug"; \
194 vdso_img_insttargets := $(vdso_img_sodbg:%.dbg=install_%)
196 $(MODLIB)/vdso: FORCE
197 @mkdir -p $(MODLIB)/vdso
199 $(vdso_img_insttargets): install_%: $(obj)/%.dbg $(MODLIB)/vdso
200 $(call cmd,vdso_install)
202 PHONY += vdso_install $(vdso_img_insttargets)
203 vdso_install: $(vdso_img_insttargets)
205 clean-files := vdso32.so vdso32.so.dbg vdso64* vdso-image-*.c vdsox32.so*