2 # Building vDSO images for x86.
5 KBUILD_CFLAGS += $(DISABLE_LTO)
8 OBJECT_FILES_NON_STANDARD := y
10 # Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
13 VDSO64-$(CONFIG_X86_64) := y
14 VDSOX32-$(CONFIG_X86_X32_ABI) := y
15 VDSO32-$(CONFIG_X86_32) := y
16 VDSO32-$(CONFIG_IA32_EMULATION) := y
18 # files to link into the vdso
19 vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o
21 # files to link into kernel
23 OBJECT_FILES_NON_STANDARD_vma.o := n
25 # vDSO images to build
26 vdso_img-$(VDSO64-y) += 64
27 vdso_img-$(VDSOX32-y) += x32
28 vdso_img-$(VDSO32-y) += 32
30 obj-$(VDSO32-y) += vdso32-setup.o
32 vobjs := $(foreach F,$(vobjs-y),$(obj)/$F)
34 $(obj)/vdso.o: $(obj)/vdso.so
36 targets += vdso.lds $(vobjs-y)
38 # Build the vDSO image C files and link them in.
39 vdso_img_objs := $(vdso_img-y:%=vdso-image-%.o)
40 vdso_img_cfiles := $(vdso_img-y:%=vdso-image-%.c)
41 vdso_img_sodbg := $(vdso_img-y:%=vdso%.so.dbg)
42 obj-y += $(vdso_img_objs)
43 targets += $(vdso_img_cfiles)
44 targets += $(vdso_img_sodbg)
45 .SECONDARY: $(vdso_img-y:%=$(obj)/vdso-image-%.c) \
46 $(vdso_img-y:%=$(obj)/vdso%.so)
48 export CPPFLAGS_vdso.lds += -P -C
50 VDSO_LDFLAGS_vdso.lds = -m elf_x86_64 -soname linux-vdso.so.1 --no-undefined \
53 $(obj)/vdso64.so.dbg: $(src)/vdso.lds $(vobjs) FORCE
54 $(call if_changed,vdso)
56 HOST_EXTRACFLAGS += -I$(srctree)/tools/include -I$(srctree)/include/uapi -I$(srctree)/arch/$(SUBARCH)/include/uapi
59 quiet_cmd_vdso2c = VDSO2C $@
61 $(obj)/vdso2c $< $(<:%.dbg=%) $@
64 $(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso%.so $(obj)/vdso2c FORCE
65 $(call if_changed,vdso2c)
68 # Don't omit frame pointers for ease of userspace debugging, but do
69 # optimize sibling calls.
71 CFL := $(PROFILING) -mcmodel=small -fPIC -O2 -fasynchronous-unwind-tables -m64 \
72 $(filter -g%,$(KBUILD_CFLAGS)) $(call cc-option, -fno-stack-protector) \
73 -fno-omit-frame-pointer -foptimize-sibling-calls \
74 -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO
76 $(vobjs): KBUILD_CFLAGS := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS)) $(CFL)
79 # vDSO code runs in userspace and -pg doesn't help with profiling anyway.
81 CFLAGS_REMOVE_vdso-note.o = -pg
82 CFLAGS_REMOVE_vclock_gettime.o = -pg
83 CFLAGS_REMOVE_vgetcpu.o = -pg
84 CFLAGS_REMOVE_vvar.o = -pg
87 # X32 processes use x32 vDSO to access 64bit kernel data.
89 # Build x32 vDSO image:
90 # 1. Compile x32 vDSO as 64bit.
91 # 2. Convert object files to x32.
92 # 3. Build x32 VDSO image with x32 objects, which contains 64bit codes
93 # so that it can reach 64bit address space with 64bit pointers.
96 CPPFLAGS_vdsox32.lds = $(CPPFLAGS_vdso.lds)
97 VDSO_LDFLAGS_vdsox32.lds = -m elf32_x86_64 -soname linux-vdso.so.1 \
100 # 64-bit objects to re-brand as x32
101 vobjs64-for-x32 := $(filter-out $(vobjs-nox32),$(vobjs-y))
103 # x32-rebranded versions
104 vobjx32s-y := $(vobjs64-for-x32:.o=-x32.o)
106 # same thing, but in the output directory
107 vobjx32s := $(foreach F,$(vobjx32s-y),$(obj)/$F)
109 # Convert 64bit object file to x32 for x32 vDSO.
110 quiet_cmd_x32 = X32 $@
111 cmd_x32 = $(OBJCOPY) -O elf32-x86-64 $< $@
113 $(obj)/%-x32.o: $(obj)/%.o FORCE
114 $(call if_changed,x32)
116 targets += vdsox32.lds $(vobjx32s-y)
118 $(obj)/%.so: OBJCOPYFLAGS := -S
119 $(obj)/%.so: $(obj)/%.so.dbg
120 $(call if_changed,objcopy)
122 $(obj)/vdsox32.so.dbg: $(src)/vdsox32.lds $(vobjx32s) FORCE
123 $(call if_changed,vdso)
125 CPPFLAGS_vdso32.lds = $(CPPFLAGS_vdso.lds)
126 VDSO_LDFLAGS_vdso32.lds = -m elf_i386 -soname linux-gate.so.1
128 # This makes sure the $(obj) subdirectory exists even though vdso32/
129 # is not a kbuild sub-make subdirectory.
130 override obj-dirs = $(dir $(obj)) $(obj)/vdso32/
132 targets += vdso32/vdso32.lds
133 targets += vdso32/note.o vdso32/system_call.o vdso32/sigreturn.o
134 targets += vdso32/vclock_gettime.o
136 KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS)) -DBUILD_VDSO
137 $(obj)/vdso32.so.dbg: KBUILD_AFLAGS = $(KBUILD_AFLAGS_32)
138 $(obj)/vdso32.so.dbg: asflags-$(CONFIG_X86_64) += -m32
140 KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS))
141 KBUILD_CFLAGS_32 := $(filter-out -mcmodel=kernel,$(KBUILD_CFLAGS_32))
142 KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32))
143 KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32))
144 KBUILD_CFLAGS_32 := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS_32))
145 KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic
146 KBUILD_CFLAGS_32 += $(call cc-option, -fno-stack-protector)
147 KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls)
148 KBUILD_CFLAGS_32 += -fno-omit-frame-pointer
149 KBUILD_CFLAGS_32 += -DDISABLE_BRANCH_PROFILING
150 $(obj)/vdso32.so.dbg: KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
152 $(obj)/vdso32.so.dbg: FORCE \
153 $(obj)/vdso32/vdso32.lds \
154 $(obj)/vdso32/vclock_gettime.o \
155 $(obj)/vdso32/note.o \
156 $(obj)/vdso32/system_call.o \
157 $(obj)/vdso32/sigreturn.o
158 $(call if_changed,vdso)
161 # The DSO images are built using a special linker script.
163 quiet_cmd_vdso = VDSO $@
164 cmd_vdso = $(LD) -nostdlib -o $@ \
165 $(VDSO_LDFLAGS) $(VDSO_LDFLAGS_$(filter %.lds,$(^F))) \
166 -T $(filter %.lds,$^) $(filter %.o,$^) && \
167 sh $(srctree)/$(src)/checkundef.sh '$(NM)' '$@'
169 VDSO_LDFLAGS = -shared $(call ld-option, --hash-style=both) \
170 $(call ld-option, --build-id) $(call ld-option, --eh-frame-hdr) \
175 # Install the unstripped copies of vdso*.so. If our toolchain supports
176 # build-id, install .build-id links as well.
178 quiet_cmd_vdso_install = INSTALL $(@:install_%=%)
179 define cmd_vdso_install
180 cp $< "$(MODLIB)/vdso/$(@:install_%=%)"; \
181 if readelf -n $< |grep -q 'Build ID'; then \
182 buildid=`readelf -n $< |grep 'Build ID' |sed -e 's/^.*Build ID: \(.*\)$$/\1/'`; \
183 first=`echo $$buildid | cut -b-2`; \
184 last=`echo $$buildid | cut -b3-`; \
185 mkdir -p "$(MODLIB)/vdso/.build-id/$$first"; \
186 ln -sf "../../$(@:install_%=%)" "$(MODLIB)/vdso/.build-id/$$first/$$last.debug"; \
190 vdso_img_insttargets := $(vdso_img_sodbg:%.dbg=install_%)
192 $(MODLIB)/vdso: FORCE
193 @mkdir -p $(MODLIB)/vdso
195 $(vdso_img_insttargets): install_%: $(obj)/%.dbg $(MODLIB)/vdso
196 $(call cmd,vdso_install)
198 PHONY += vdso_install $(vdso_img_insttargets)
199 vdso_install: $(vdso_img_insttargets)
201 clean-files := vdso32.so vdso32.so.dbg vdso64* vdso-image-*.c vdsox32.so*