1# SPDX-License-Identifier: GPL-2.0 2# 3# Building vDSO images for x86. 4# 5 6# Include the generic Makefile to check the built vDSO: 7include $(srctree)/lib/vdso/Makefile 8 9# Files to link into the vDSO: 10vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o 11vobjs32-y := vdso32/note.o vdso32/system_call.o vdso32/sigreturn.o 12vobjs32-y += vdso32/vclock_gettime.o vdso32/vgetcpu.o 13vobjs-$(CONFIG_X86_SGX) += vsgx.o 14 15# Files to link into the kernel: 16obj-y += vma.o extable.o 17 18# vDSO images to build: 19obj-$(CONFIG_X86_64) += vdso-image-64.o 20obj-$(CONFIG_X86_X32_ABI) += vdso-image-x32.o 21obj-$(CONFIG_COMPAT_32) += vdso-image-32.o vdso32-setup.o 22 23vobjs := $(addprefix $(obj)/, $(vobjs-y)) 24vobjs32 := $(addprefix $(obj)/, $(vobjs32-y)) 25 26$(obj)/vdso.o: $(obj)/vdso.so 27 28targets += vdso.lds $(vobjs-y) 29targets += vdso32/vdso32.lds $(vobjs32-y) 30 31targets += $(foreach x, 64 x32 32, vdso-image-$(x).c vdso$(x).so vdso$(x).so.dbg) 32 33CPPFLAGS_vdso.lds += -P -C 34 35VDSO_LDFLAGS_vdso.lds = -m elf_x86_64 -soname linux-vdso.so.1 --no-undefined \ 36 -z max-page-size=4096 37 38$(obj)/vdso64.so.dbg: $(obj)/vdso.lds $(vobjs) FORCE 39 $(call if_changed,vdso_and_check) 40 41HOST_EXTRACFLAGS += -I$(srctree)/tools/include -I$(srctree)/include/uapi -I$(srctree)/arch/$(SUBARCH)/include/uapi 42hostprogs += vdso2c 43 44quiet_cmd_vdso2c = VDSO2C $@ 45 cmd_vdso2c = $(obj)/vdso2c $< $(<:%.dbg=%) $@ 46 47$(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso%.so $(obj)/vdso2c FORCE 48 $(call if_changed,vdso2c) 49 50# 51# Don't omit frame pointers for ease of userspace debugging, but do 52# optimize sibling calls. 53# 54CFL := $(PROFILING) -mcmodel=small -fPIC -O2 -fasynchronous-unwind-tables -m64 \ 55 $(filter -g%,$(KBUILD_CFLAGS)) -fno-stack-protector \ 56 -fno-omit-frame-pointer -foptimize-sibling-calls \ 57 -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO 58 59ifdef CONFIG_MITIGATION_RETPOLINE 60ifneq ($(RETPOLINE_VDSO_CFLAGS),) 61 CFL += $(RETPOLINE_VDSO_CFLAGS) 62endif 63endif 64 65$(vobjs): KBUILD_CFLAGS := $(filter-out $(PADDING_CFLAGS) $(CC_FLAGS_LTO) $(CC_FLAGS_CFI) $(RANDSTRUCT_CFLAGS) $(GCC_PLUGINS_CFLAGS) $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS)) $(CFL) 66$(vobjs): KBUILD_AFLAGS += -DBUILD_VDSO 67 68# 69# vDSO code runs in userspace and -pg doesn't help with profiling anyway. 70# 71CFLAGS_REMOVE_vclock_gettime.o = -pg 72CFLAGS_REMOVE_vdso32/vclock_gettime.o = -pg 73CFLAGS_REMOVE_vgetcpu.o = -pg 74CFLAGS_REMOVE_vdso32/vgetcpu.o = -pg 75CFLAGS_REMOVE_vsgx.o = -pg 76 77# 78# X32 processes use x32 vDSO to access 64bit kernel data. 79# 80# Build x32 vDSO image: 81# 1. Compile x32 vDSO as 64bit. 82# 2. Convert object files to x32. 83# 3. Build x32 VDSO image with x32 objects, which contains 64bit codes 84# so that it can reach 64bit address space with 64bit pointers. 85# 86 87CPPFLAGS_vdsox32.lds = $(CPPFLAGS_vdso.lds) 88VDSO_LDFLAGS_vdsox32.lds = -m elf32_x86_64 -soname linux-vdso.so.1 \ 89 -z max-page-size=4096 90 91# x32-rebranded versions 92vobjx32s-y := $(vobjs-y:.o=-x32.o) 93 94# same thing, but in the output directory 95vobjx32s := $(addprefix $(obj)/, $(vobjx32s-y)) 96 97# Convert 64bit object file to x32 for x32 vDSO. 98quiet_cmd_x32 = X32 $@ 99 cmd_x32 = $(OBJCOPY) -O elf32-x86-64 $< $@ 100 101$(obj)/%-x32.o: $(obj)/%.o FORCE 102 $(call if_changed,x32) 103 104targets += vdsox32.lds $(vobjx32s-y) 105 106$(obj)/%.so: OBJCOPYFLAGS := -S --remove-section __ex_table 107$(obj)/%.so: $(obj)/%.so.dbg FORCE 108 $(call if_changed,objcopy) 109 110$(obj)/vdsox32.so.dbg: $(obj)/vdsox32.lds $(vobjx32s) FORCE 111 $(call if_changed,vdso_and_check) 112 113CPPFLAGS_vdso32/vdso32.lds = $(CPPFLAGS_vdso.lds) 114VDSO_LDFLAGS_vdso32.lds = -m elf_i386 -soname linux-gate.so.1 115 116KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS)) -DBUILD_VDSO 117$(obj)/vdso32.so.dbg: KBUILD_AFLAGS = $(KBUILD_AFLAGS_32) 118$(obj)/vdso32.so.dbg: asflags-$(CONFIG_X86_64) += -m32 119 120KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS)) 121KBUILD_CFLAGS_32 := $(filter-out -mcmodel=kernel,$(KBUILD_CFLAGS_32)) 122KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32)) 123KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32)) 124KBUILD_CFLAGS_32 := $(filter-out $(RANDSTRUCT_CFLAGS),$(KBUILD_CFLAGS_32)) 125KBUILD_CFLAGS_32 := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS_32)) 126KBUILD_CFLAGS_32 := $(filter-out $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS_32)) 127KBUILD_CFLAGS_32 := $(filter-out $(CC_FLAGS_LTO),$(KBUILD_CFLAGS_32)) 128KBUILD_CFLAGS_32 := $(filter-out $(CC_FLAGS_CFI),$(KBUILD_CFLAGS_32)) 129KBUILD_CFLAGS_32 := $(filter-out $(PADDING_CFLAGS),$(KBUILD_CFLAGS_32)) 130KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic 131KBUILD_CFLAGS_32 += -fno-stack-protector 132KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls) 133KBUILD_CFLAGS_32 += -fno-omit-frame-pointer 134KBUILD_CFLAGS_32 += -DDISABLE_BRANCH_PROFILING 135 136ifdef CONFIG_MITIGATION_RETPOLINE 137ifneq ($(RETPOLINE_VDSO_CFLAGS),) 138 KBUILD_CFLAGS_32 += $(RETPOLINE_VDSO_CFLAGS) 139endif 140endif 141 142$(obj)/vdso32.so.dbg: KBUILD_CFLAGS = $(KBUILD_CFLAGS_32) 143 144$(obj)/vdso32.so.dbg: $(obj)/vdso32/vdso32.lds $(vobjs32) FORCE 145 $(call if_changed,vdso_and_check) 146 147# 148# The DSO images are built using a special linker script. 149# 150quiet_cmd_vdso = VDSO $@ 151 cmd_vdso = $(LD) -o $@ \ 152 $(VDSO_LDFLAGS) $(VDSO_LDFLAGS_$(filter %.lds,$(^F))) \ 153 -T $(filter %.lds,$^) $(filter %.o,$^) && \ 154 sh $(src)/checkundef.sh '$(NM)' '$@' 155 156VDSO_LDFLAGS = -shared --hash-style=both --build-id=sha1 \ 157 $(call ld-option, --eh-frame-hdr) -Bsymbolic -z noexecstack 158 159quiet_cmd_vdso_and_check = VDSO $@ 160 cmd_vdso_and_check = $(cmd_vdso); $(cmd_vdso_check) 161