2 # Building vDSO images for x86.
5 KBUILD_CFLAGS += $(DISABLE_LTO)
8 VDSO64-$(CONFIG_X86_64) := y
9 VDSOX32-$(CONFIG_X86_X32_ABI) := y
10 VDSO32-$(CONFIG_X86_32) := y
11 VDSO32-$(CONFIG_IA32_EMULATION) := y
13 # files to link into the vdso
14 vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o
16 # files to link into kernel
19 # vDSO images to build
20 vdso_img-$(VDSO64-y) += 64
21 vdso_img-$(VDSOX32-y) += x32
22 vdso_img-$(VDSO32-y) += 32
24 obj-$(VDSO32-y) += vdso32-setup.o
26 vobjs := $(foreach F,$(vobjs-y),$(obj)/$F)
28 $(obj)/vdso.o: $(obj)/vdso.so
30 targets += vdso.lds $(vobjs-y)
32 # Build the vDSO image C files and link them in.
33 vdso_img_objs := $(vdso_img-y:%=vdso-image-%.o)
34 vdso_img_cfiles := $(vdso_img-y:%=vdso-image-%.c)
35 vdso_img_sodbg := $(vdso_img-y:%=vdso%.so.dbg)
36 obj-y += $(vdso_img_objs)
37 targets += $(vdso_img_cfiles)
38 targets += $(vdso_img_sodbg)
39 .SECONDARY: $(vdso_img-y:%=$(obj)/vdso-image-%.c) \
40 $(vdso_img-y:%=$(obj)/vdso%.so)
42 export CPPFLAGS_vdso.lds += -P -C
44 VDSO_LDFLAGS_vdso.lds = -m elf_x86_64 -soname linux-vdso.so.1 --no-undefined \
47 $(obj)/vdso64.so.dbg: $(src)/vdso.lds $(vobjs) FORCE
48 $(call if_changed,vdso)
50 HOST_EXTRACFLAGS += -I$(srctree)/tools/include -I$(srctree)/include/uapi -I$(srctree)/arch/x86/include/uapi
53 quiet_cmd_vdso2c = VDSO2C $@
55 $(obj)/vdso2c $< $(<:%.dbg=%) $@
58 $(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso%.so $(obj)/vdso2c FORCE
59 $(call if_changed,vdso2c)
62 # Don't omit frame pointers for ease of userspace debugging, but do
63 # optimize sibling calls.
65 CFL := $(PROFILING) -mcmodel=small -fPIC -O2 -fasynchronous-unwind-tables -m64 \
66 $(filter -g%,$(KBUILD_CFLAGS)) $(call cc-option, -fno-stack-protector) \
67 -fno-omit-frame-pointer -foptimize-sibling-calls \
68 -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO
70 $(vobjs): KBUILD_CFLAGS += $(CFL)
73 # vDSO code runs in userspace and -pg doesn't help with profiling anyway.
75 CFLAGS_REMOVE_vdso-note.o = -pg
76 CFLAGS_REMOVE_vclock_gettime.o = -pg
77 CFLAGS_REMOVE_vgetcpu.o = -pg
78 CFLAGS_REMOVE_vvar.o = -pg
81 # X32 processes use x32 vDSO to access 64bit kernel data.
83 # Build x32 vDSO image:
84 # 1. Compile x32 vDSO as 64bit.
85 # 2. Convert object files to x32.
86 # 3. Build x32 VDSO image with x32 objects, which contains 64bit codes
87 # so that it can reach 64bit address space with 64bit pointers.
90 CPPFLAGS_vdsox32.lds = $(CPPFLAGS_vdso.lds)
91 VDSO_LDFLAGS_vdsox32.lds = -m elf32_x86_64 -soname linux-vdso.so.1 \
94 # 64-bit objects to re-brand as x32
95 vobjs64-for-x32 := $(filter-out $(vobjs-nox32),$(vobjs-y))
97 # x32-rebranded versions
98 vobjx32s-y := $(vobjs64-for-x32:.o=-x32.o)
100 # same thing, but in the output directory
101 vobjx32s := $(foreach F,$(vobjx32s-y),$(obj)/$F)
103 # Convert 64bit object file to x32 for x32 vDSO.
104 quiet_cmd_x32 = X32 $@
105 cmd_x32 = $(OBJCOPY) -O elf32-x86-64 $< $@
107 $(obj)/%-x32.o: $(obj)/%.o FORCE
108 $(call if_changed,x32)
110 targets += vdsox32.lds $(vobjx32s-y)
112 $(obj)/%.so: OBJCOPYFLAGS := -S
113 $(obj)/%.so: $(obj)/%.so.dbg
114 $(call if_changed,objcopy)
116 $(obj)/vdsox32.so.dbg: $(src)/vdsox32.lds $(vobjx32s) FORCE
117 $(call if_changed,vdso)
119 CPPFLAGS_vdso32.lds = $(CPPFLAGS_vdso.lds)
120 VDSO_LDFLAGS_vdso32.lds = -m elf_i386 -soname linux-gate.so.1
122 # This makes sure the $(obj) subdirectory exists even though vdso32/
123 # is not a kbuild sub-make subdirectory.
124 override obj-dirs = $(dir $(obj)) $(obj)/vdso32/
126 targets += vdso32/vdso32.lds
127 targets += vdso32/note.o vdso32/vclock_gettime.o vdso32/system_call.o
128 targets += vdso32/vclock_gettime.o
130 KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS)) -DBUILD_VDSO
131 $(obj)/vdso32.so.dbg: KBUILD_AFLAGS = $(KBUILD_AFLAGS_32)
132 $(obj)/vdso32.so.dbg: asflags-$(CONFIG_X86_64) += -m32
134 KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS))
135 KBUILD_CFLAGS_32 := $(filter-out -mcmodel=kernel,$(KBUILD_CFLAGS_32))
136 KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32))
137 KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32))
138 KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic
139 KBUILD_CFLAGS_32 += $(call cc-option, -fno-stack-protector)
140 KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls)
141 KBUILD_CFLAGS_32 += -fno-omit-frame-pointer
142 KBUILD_CFLAGS_32 += -DDISABLE_BRANCH_PROFILING
143 $(obj)/vdso32.so.dbg: KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
145 $(obj)/vdso32.so.dbg: FORCE \
146 $(obj)/vdso32/vdso32.lds \
147 $(obj)/vdso32/vclock_gettime.o \
148 $(obj)/vdso32/note.o \
149 $(obj)/vdso32/system_call.o
150 $(call if_changed,vdso)
153 # The DSO images are built using a special linker script.
155 quiet_cmd_vdso = VDSO $@
156 cmd_vdso = $(LD) -nostdlib -o $@ \
157 $(VDSO_LDFLAGS) $(VDSO_LDFLAGS_$(filter %.lds,$(^F))) \
158 -T $(filter %.lds,$^) $(filter %.o,$^) && \
159 sh $(srctree)/$(src)/checkundef.sh '$(NM)' '$@'
161 VDSO_LDFLAGS = -shared $(call ld-option, --hash-style=both) \
162 $(call ld-option, --build-id) $(call ld-option, --eh-frame-hdr) \
167 # Install the unstripped copies of vdso*.so. If our toolchain supports
168 # build-id, install .build-id links as well.
170 quiet_cmd_vdso_install = INSTALL $(@:install_%=%)
171 define cmd_vdso_install
172 cp $< "$(MODLIB)/vdso/$(@:install_%=%)"; \
173 if readelf -n $< |grep -q 'Build ID'; then \
174 buildid=`readelf -n $< |grep 'Build ID' |sed -e 's/^.*Build ID: \(.*\)$$/\1/'`; \
175 first=`echo $$buildid | cut -b-2`; \
176 last=`echo $$buildid | cut -b3-`; \
177 mkdir -p "$(MODLIB)/vdso/.build-id/$$first"; \
178 ln -sf "../../$(@:install_%=%)" "$(MODLIB)/vdso/.build-id/$$first/$$last.debug"; \
182 vdso_img_insttargets := $(vdso_img_sodbg:%.dbg=install_%)
184 $(MODLIB)/vdso: FORCE
185 @mkdir -p $(MODLIB)/vdso
187 $(vdso_img_insttargets): install_%: $(obj)/%.dbg $(MODLIB)/vdso FORCE
188 $(call cmd,vdso_install)
190 PHONY += vdso_install $(vdso_img_insttargets)
191 vdso_install: $(vdso_img_insttargets) FORCE
193 clean-files := vdso32.so vdso32.so.dbg vdso64* vdso-image-*.c vdsox32.so*