1#
2# Building vDSO images for x86.
3#
4
5KBUILD_CFLAGS += $(DISABLE_LTO)
6
7VDSO64-$(CONFIG_X86_64)		:= y
8VDSOX32-$(CONFIG_X86_X32_ABI)	:= y
9VDSO32-$(CONFIG_X86_32)		:= y
10VDSO32-$(CONFIG_COMPAT)		:= y
11
12# files to link into the vdso
13vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o
14
15# files to link into kernel
16obj-y				+= vma.o
17
18# vDSO images to build
19vdso_img-$(VDSO64-y)		+= 64
20vdso_img-$(VDSOX32-y)		+= x32
21vdso_img-$(VDSO32-y)		+= 32-int80
22vdso_img-$(CONFIG_COMPAT)	+= 32-syscall
23vdso_img-$(VDSO32-y)		+= 32-sysenter
24
25obj-$(VDSO32-y)			+= vdso32-setup.o
26
27vobjs := $(foreach F,$(vobjs-y),$(obj)/$F)
28
29$(obj)/vdso.o: $(obj)/vdso.so
30
31targets += vdso.lds $(vobjs-y)
32
33# Build the vDSO image C files and link them in.
34vdso_img_objs := $(vdso_img-y:%=vdso-image-%.o)
35vdso_img_cfiles := $(vdso_img-y:%=vdso-image-%.c)
36vdso_img_sodbg := $(vdso_img-y:%=vdso%.so.dbg)
37obj-y += $(vdso_img_objs)
38targets += $(vdso_img_cfiles)
39targets += $(vdso_img_sodbg)
40.SECONDARY: $(vdso_img-y:%=$(obj)/vdso-image-%.c) \
41	$(vdso_img-y:%=$(obj)/vdso%.so)
42
43export CPPFLAGS_vdso.lds += -P -C
44
45VDSO_LDFLAGS_vdso.lds = -m64 -Wl,-soname=linux-vdso.so.1 \
46			-Wl,--no-undefined \
47			-Wl,-z,max-page-size=4096 -Wl,-z,common-page-size=4096 \
48			$(DISABLE_LTO)
49
50$(obj)/vdso64.so.dbg: $(src)/vdso.lds $(vobjs) FORCE
51	$(call if_changed,vdso)
52
53HOST_EXTRACFLAGS += -I$(srctree)/tools/include
54hostprogs-y			+= vdso2c
55
56quiet_cmd_vdso2c = VDSO2C  $@
57define cmd_vdso2c
58	$(obj)/vdso2c $< $(<:%.dbg=%) $@
59endef
60
61$(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso%.so $(obj)/vdso2c FORCE
62	$(call if_changed,vdso2c)
63
64#
65# Don't omit frame pointers for ease of userspace debugging, but do
66# optimize sibling calls.
67#
68CFL := $(PROFILING) -mcmodel=small -fPIC -O2 -fasynchronous-unwind-tables -m64 \
69       $(filter -g%,$(KBUILD_CFLAGS)) $(call cc-option, -fno-stack-protector) \
70       -fno-omit-frame-pointer -foptimize-sibling-calls \
71       -DDISABLE_BRANCH_PROFILING
72
73$(vobjs): KBUILD_CFLAGS += $(CFL)
74
75#
76# vDSO code runs in userspace and -pg doesn't help with profiling anyway.
77#
78CFLAGS_REMOVE_vdso-note.o = -pg
79CFLAGS_REMOVE_vclock_gettime.o = -pg
80CFLAGS_REMOVE_vgetcpu.o = -pg
81CFLAGS_REMOVE_vvar.o = -pg
82
83#
84# X32 processes use x32 vDSO to access 64bit kernel data.
85#
86# Build x32 vDSO image:
87# 1. Compile x32 vDSO as 64bit.
88# 2. Convert object files to x32.
89# 3. Build x32 VDSO image with x32 objects, which contains 64bit codes
90# so that it can reach 64bit address space with 64bit pointers.
91#
92
93CPPFLAGS_vdsox32.lds = $(CPPFLAGS_vdso.lds)
94VDSO_LDFLAGS_vdsox32.lds = -Wl,-m,elf32_x86_64 \
95			   -Wl,-soname=linux-vdso.so.1 \
96			   -Wl,-z,max-page-size=4096 \
97			   -Wl,-z,common-page-size=4096
98
99# 64-bit objects to re-brand as x32
100vobjs64-for-x32 := $(filter-out $(vobjs-nox32),$(vobjs-y))
101
102# x32-rebranded versions
103vobjx32s-y := $(vobjs64-for-x32:.o=-x32.o)
104
105# same thing, but in the output directory
106vobjx32s := $(foreach F,$(vobjx32s-y),$(obj)/$F)
107
108# Convert 64bit object file to x32 for x32 vDSO.
109quiet_cmd_x32 = X32     $@
110      cmd_x32 = $(OBJCOPY) -O elf32-x86-64 $< $@
111
112$(obj)/%-x32.o: $(obj)/%.o FORCE
113	$(call if_changed,x32)
114
115targets += vdsox32.lds $(vobjx32s-y)
116
117$(obj)/%.so: OBJCOPYFLAGS := -S
118$(obj)/%.so: $(obj)/%.so.dbg
119	$(call if_changed,objcopy)
120
121$(obj)/vdsox32.so.dbg: $(src)/vdsox32.lds $(vobjx32s) FORCE
122	$(call if_changed,vdso)
123
124#
125# Build multiple 32-bit vDSO images to choose from at boot time.
126#
127vdso32.so-$(VDSO32-y)		+= int80
128vdso32.so-$(CONFIG_COMPAT)	+= syscall
129vdso32.so-$(VDSO32-y)		+= sysenter
130
131vdso32-images			= $(vdso32.so-y:%=vdso32-%.so)
132
133CPPFLAGS_vdso32.lds = $(CPPFLAGS_vdso.lds)
134VDSO_LDFLAGS_vdso32.lds = -m32 -Wl,-m,elf_i386 -Wl,-soname=linux-gate.so.1
135
136# This makes sure the $(obj) subdirectory exists even though vdso32/
137# is not a kbuild sub-make subdirectory.
138override obj-dirs = $(dir $(obj)) $(obj)/vdso32/
139
140targets += vdso32/vdso32.lds
141targets += vdso32/note.o vdso32/vclock_gettime.o $(vdso32.so-y:%=vdso32/%.o)
142targets += vdso32/vclock_gettime.o
143
144$(obj)/vdso32.o: $(vdso32-images:%=$(obj)/%)
145
146KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS))
147$(vdso32-images:%=$(obj)/%.dbg): KBUILD_AFLAGS = $(KBUILD_AFLAGS_32)
148$(vdso32-images:%=$(obj)/%.dbg): asflags-$(CONFIG_X86_64) += -m32
149
150KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS))
151KBUILD_CFLAGS_32 := $(filter-out -mcmodel=kernel,$(KBUILD_CFLAGS_32))
152KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32))
153KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32))
154KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic
155KBUILD_CFLAGS_32 += $(call cc-option, -fno-stack-protector)
156KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls)
157KBUILD_CFLAGS_32 += -fno-omit-frame-pointer
158KBUILD_CFLAGS_32 += -DDISABLE_BRANCH_PROFILING
159$(vdso32-images:%=$(obj)/%.dbg): KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
160
161$(vdso32-images:%=$(obj)/%.dbg): $(obj)/vdso32-%.so.dbg: FORCE \
162				 $(obj)/vdso32/vdso32.lds \
163				 $(obj)/vdso32/vclock_gettime.o \
164				 $(obj)/vdso32/note.o \
165				 $(obj)/vdso32/%.o
166	$(call if_changed,vdso)
167
168#
169# The DSO images are built using a special linker script.
170#
171quiet_cmd_vdso = VDSO    $@
172      cmd_vdso = $(CC) -nostdlib -o $@ \
173		       $(VDSO_LDFLAGS) $(VDSO_LDFLAGS_$(filter %.lds,$(^F))) \
174		       -Wl,-T,$(filter %.lds,$^) $(filter %.o,$^) && \
175		 sh $(srctree)/$(src)/checkundef.sh '$(NM)' '$@'
176
177VDSO_LDFLAGS = -fPIC -shared $(call cc-ldoption, -Wl$(comma)--hash-style=sysv) \
178	$(call cc-ldoption, -Wl$(comma)--build-id) -Wl,-Bsymbolic $(LTO_CFLAGS)
179GCOV_PROFILE := n
180
181#
182# Install the unstripped copies of vdso*.so.  If our toolchain supports
183# build-id, install .build-id links as well.
184#
185quiet_cmd_vdso_install = INSTALL $(@:install_%=%)
186define cmd_vdso_install
187	cp $< "$(MODLIB)/vdso/$(@:install_%=%)"; \
188	if readelf -n $< |grep -q 'Build ID'; then \
189	  buildid=`readelf -n $< |grep 'Build ID' |sed -e 's/^.*Build ID: \(.*\)$$/\1/'`; \
190	  first=`echo $$buildid | cut -b-2`; \
191	  last=`echo $$buildid | cut -b3-`; \
192	  mkdir -p "$(MODLIB)/vdso/.build-id/$$first"; \
193	  ln -sf "../../$(@:install_%=%)" "$(MODLIB)/vdso/.build-id/$$first/$$last.debug"; \
194	fi
195endef
196
197vdso_img_insttargets := $(vdso_img_sodbg:%.dbg=install_%)
198
199$(MODLIB)/vdso: FORCE
200	@mkdir -p $(MODLIB)/vdso
201
202$(vdso_img_insttargets): install_%: $(obj)/%.dbg $(MODLIB)/vdso FORCE
203	$(call cmd,vdso_install)
204
205PHONY += vdso_install $(vdso_img_insttargets)
206vdso_install: $(vdso_img_insttargets) FORCE
207
208clean-files := vdso32-syscall* vdso32-sysenter* vdso32-int80*
209