1#
2# Building vDSO images for x86.
3#
4
5KBUILD_CFLAGS += $(DISABLE_LTO)
6KASAN_SANITIZE := n
7
8VDSO64-$(CONFIG_X86_64)		:= y
9VDSOX32-$(CONFIG_X86_X32_ABI)	:= y
10VDSO32-$(CONFIG_X86_32)		:= y
11VDSO32-$(CONFIG_IA32_EMULATION)	:= y
12
13# files to link into the vdso
14vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o
15
16# files to link into kernel
17obj-y				+= vma.o
18
19# vDSO images to build
20vdso_img-$(VDSO64-y)		+= 64
21vdso_img-$(VDSOX32-y)		+= x32
22vdso_img-$(VDSO32-y)		+= 32
23
24obj-$(VDSO32-y)			+= vdso32-setup.o
25
26vobjs := $(foreach F,$(vobjs-y),$(obj)/$F)
27
28$(obj)/vdso.o: $(obj)/vdso.so
29
30targets += vdso.lds $(vobjs-y)
31
32# Build the vDSO image C files and link them in.
33vdso_img_objs := $(vdso_img-y:%=vdso-image-%.o)
34vdso_img_cfiles := $(vdso_img-y:%=vdso-image-%.c)
35vdso_img_sodbg := $(vdso_img-y:%=vdso%.so.dbg)
36obj-y += $(vdso_img_objs)
37targets += $(vdso_img_cfiles)
38targets += $(vdso_img_sodbg)
39.SECONDARY: $(vdso_img-y:%=$(obj)/vdso-image-%.c) \
40	$(vdso_img-y:%=$(obj)/vdso%.so)
41
42export CPPFLAGS_vdso.lds += -P -C
43
44VDSO_LDFLAGS_vdso.lds = -m64 -Wl,-soname=linux-vdso.so.1 \
45			-Wl,--no-undefined \
46			-Wl,-z,max-page-size=4096 -Wl,-z,common-page-size=4096 \
47			$(DISABLE_LTO)
48
49$(obj)/vdso64.so.dbg: $(src)/vdso.lds $(vobjs) FORCE
50	$(call if_changed,vdso)
51
52HOST_EXTRACFLAGS += -I$(srctree)/tools/include -I$(srctree)/include/uapi -I$(srctree)/arch/x86/include/uapi
53hostprogs-y			+= vdso2c
54
55quiet_cmd_vdso2c = VDSO2C  $@
56define cmd_vdso2c
57	$(obj)/vdso2c $< $(<:%.dbg=%) $@
58endef
59
60$(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso%.so $(obj)/vdso2c FORCE
61	$(call if_changed,vdso2c)
62
63#
64# Don't omit frame pointers for ease of userspace debugging, but do
65# optimize sibling calls.
66#
67CFL := $(PROFILING) -mcmodel=small -fPIC -O2 -fasynchronous-unwind-tables -m64 \
68       $(filter -g%,$(KBUILD_CFLAGS)) $(call cc-option, -fno-stack-protector) \
69       -fno-omit-frame-pointer -foptimize-sibling-calls \
70       -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO
71
72$(vobjs): KBUILD_CFLAGS += $(CFL)
73
74#
75# vDSO code runs in userspace and -pg doesn't help with profiling anyway.
76#
77CFLAGS_REMOVE_vdso-note.o = -pg
78CFLAGS_REMOVE_vclock_gettime.o = -pg
79CFLAGS_REMOVE_vgetcpu.o = -pg
80CFLAGS_REMOVE_vvar.o = -pg
81
82#
83# X32 processes use x32 vDSO to access 64bit kernel data.
84#
85# Build x32 vDSO image:
86# 1. Compile x32 vDSO as 64bit.
87# 2. Convert object files to x32.
88# 3. Build x32 VDSO image with x32 objects, which contains 64bit codes
89# so that it can reach 64bit address space with 64bit pointers.
90#
91
92CPPFLAGS_vdsox32.lds = $(CPPFLAGS_vdso.lds)
93VDSO_LDFLAGS_vdsox32.lds = -Wl,-m,elf32_x86_64 \
94			   -Wl,-soname=linux-vdso.so.1 \
95			   -Wl,-z,max-page-size=4096 \
96			   -Wl,-z,common-page-size=4096
97
98# 64-bit objects to re-brand as x32
99vobjs64-for-x32 := $(filter-out $(vobjs-nox32),$(vobjs-y))
100
101# x32-rebranded versions
102vobjx32s-y := $(vobjs64-for-x32:.o=-x32.o)
103
104# same thing, but in the output directory
105vobjx32s := $(foreach F,$(vobjx32s-y),$(obj)/$F)
106
107# Convert 64bit object file to x32 for x32 vDSO.
108quiet_cmd_x32 = X32     $@
109      cmd_x32 = $(OBJCOPY) -O elf32-x86-64 $< $@
110
111$(obj)/%-x32.o: $(obj)/%.o FORCE
112	$(call if_changed,x32)
113
114targets += vdsox32.lds $(vobjx32s-y)
115
116$(obj)/%.so: OBJCOPYFLAGS := -S
117$(obj)/%.so: $(obj)/%.so.dbg
118	$(call if_changed,objcopy)
119
120$(obj)/vdsox32.so.dbg: $(src)/vdsox32.lds $(vobjx32s) FORCE
121	$(call if_changed,vdso)
122
123CPPFLAGS_vdso32.lds = $(CPPFLAGS_vdso.lds)
124VDSO_LDFLAGS_vdso32.lds = -m32 -Wl,-m,elf_i386 -Wl,-soname=linux-gate.so.1
125
126# This makes sure the $(obj) subdirectory exists even though vdso32/
127# is not a kbuild sub-make subdirectory.
128override obj-dirs = $(dir $(obj)) $(obj)/vdso32/
129
130targets += vdso32/vdso32.lds
131targets += vdso32/note.o vdso32/vclock_gettime.o vdso32/system_call.o
132targets += vdso32/vclock_gettime.o
133
134KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS)) -DBUILD_VDSO
135$(obj)/vdso32.so.dbg: KBUILD_AFLAGS = $(KBUILD_AFLAGS_32)
136$(obj)/vdso32.so.dbg: asflags-$(CONFIG_X86_64) += -m32
137
138KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS))
139KBUILD_CFLAGS_32 := $(filter-out -mcmodel=kernel,$(KBUILD_CFLAGS_32))
140KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32))
141KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32))
142KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic
143KBUILD_CFLAGS_32 += $(call cc-option, -fno-stack-protector)
144KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls)
145KBUILD_CFLAGS_32 += -fno-omit-frame-pointer
146KBUILD_CFLAGS_32 += -DDISABLE_BRANCH_PROFILING
147$(obj)/vdso32.so.dbg: KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
148
149$(obj)/vdso32.so.dbg: FORCE \
150		      $(obj)/vdso32/vdso32.lds \
151		      $(obj)/vdso32/vclock_gettime.o \
152		      $(obj)/vdso32/note.o \
153		      $(obj)/vdso32/system_call.o
154	$(call if_changed,vdso)
155
156#
157# The DSO images are built using a special linker script.
158#
159quiet_cmd_vdso = VDSO    $@
160      cmd_vdso = $(CC) -nostdlib -o $@ \
161		       $(VDSO_LDFLAGS) $(VDSO_LDFLAGS_$(filter %.lds,$(^F))) \
162		       -Wl,-T,$(filter %.lds,$^) $(filter %.o,$^) && \
163		 sh $(srctree)/$(src)/checkundef.sh '$(NM)' '$@'
164
165VDSO_LDFLAGS = -fPIC -shared $(call cc-ldoption, -Wl$(comma)--hash-style=both) \
166	$(call cc-ldoption, -Wl$(comma)--build-id) -Wl,-Bsymbolic $(LTO_CFLAGS)
167GCOV_PROFILE := n
168
169#
170# Install the unstripped copies of vdso*.so.  If our toolchain supports
171# build-id, install .build-id links as well.
172#
173quiet_cmd_vdso_install = INSTALL $(@:install_%=%)
174define cmd_vdso_install
175	cp $< "$(MODLIB)/vdso/$(@:install_%=%)"; \
176	if readelf -n $< |grep -q 'Build ID'; then \
177	  buildid=`readelf -n $< |grep 'Build ID' |sed -e 's/^.*Build ID: \(.*\)$$/\1/'`; \
178	  first=`echo $$buildid | cut -b-2`; \
179	  last=`echo $$buildid | cut -b3-`; \
180	  mkdir -p "$(MODLIB)/vdso/.build-id/$$first"; \
181	  ln -sf "../../$(@:install_%=%)" "$(MODLIB)/vdso/.build-id/$$first/$$last.debug"; \
182	fi
183endef
184
185vdso_img_insttargets := $(vdso_img_sodbg:%.dbg=install_%)
186
187$(MODLIB)/vdso: FORCE
188	@mkdir -p $(MODLIB)/vdso
189
190$(vdso_img_insttargets): install_%: $(obj)/%.dbg $(MODLIB)/vdso FORCE
191	$(call cmd,vdso_install)
192
193PHONY += vdso_install $(vdso_img_insttargets)
194vdso_install: $(vdso_img_insttargets) FORCE
195
196clean-files := vdso32.so vdso32.so.dbg vdso64* vdso-image-*.c vdsox32.so*
197