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