1 files changed, 162 insertions, 0 deletions
diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile
new file mode 100644
index 000000000000..f247f5f5cb44
--- /dev/null
+++ b/arch/x86/entry/vdso/Makefile
@@ -0,0 +1,162 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Building vDSO images for x86.
+#
+
+# Include the generic Makefile to check the built vDSO:
+include $(srctree)/lib/vdso/Makefile.include
+
+# Files to link into the vDSO:
+vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o vgetrandom.o vgetrandom-chacha.o
+vobjs32-y := vdso32/note.o vdso32/system_call.o vdso32/sigreturn.o
+vobjs32-y += vdso32/vclock_gettime.o vdso32/vgetcpu.o
+vobjs-$(CONFIG_X86_SGX)	+= vsgx.o
+
+# Files to link into the kernel:
+obj-y						+= vma.o extable.o
+
+# vDSO images to build:
+obj-$(CONFIG_X86_64)				+= vdso-image-64.o
+obj-$(CONFIG_X86_X32_ABI)			+= vdso-image-x32.o
+obj-$(CONFIG_COMPAT_32)				+= vdso-image-32.o vdso32-setup.o
+
+vobjs := $(addprefix $(obj)/, $(vobjs-y))
+vobjs32 := $(addprefix $(obj)/, $(vobjs32-y))
+
+$(obj)/vdso.o: $(obj)/vdso.so
+
+targets += vdso.lds $(vobjs-y)
+targets += vdso32/vdso32.lds $(vobjs32-y)
+
+targets += $(foreach x, 64 x32 32, vdso-image-$(x).c vdso$(x).so vdso$(x).so.dbg)
+
+CPPFLAGS_vdso.lds += -P -C
+
+VDSO_LDFLAGS_vdso.lds = -m elf_x86_64 -soname linux-vdso.so.1 \
+			-z max-page-size=4096
+
+$(obj)/vdso64.so.dbg: $(obj)/vdso.lds $(vobjs) FORCE
+	$(call if_changed,vdso_and_check)
+
+HOST_EXTRACFLAGS += -I$(srctree)/tools/include -I$(srctree)/include/uapi -I$(srctree)/arch/$(SUBARCH)/include/uapi
+hostprogs += vdso2c
+
+quiet_cmd_vdso2c = VDSO2C  $@
+      cmd_vdso2c = $(obj)/vdso2c $< $(<:%.dbg=%) $@
+
+$(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)) -fno-stack-protector \
+       -fno-omit-frame-pointer -foptimize-sibling-calls \
+       -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO
+
+ifdef CONFIG_MITIGATION_RETPOLINE
+ifneq ($(RETPOLINE_VDSO_CFLAGS),)
+  CFL += $(RETPOLINE_VDSO_CFLAGS)
+endif
+endif
+
+$(vobjs): KBUILD_CFLAGS := $(filter-out $(PADDING_CFLAGS) $(CC_FLAGS_LTO) $(CC_FLAGS_CFI) $(RANDSTRUCT_CFLAGS) $(KSTACK_ERASE_CFLAGS) $(GCC_PLUGINS_CFLAGS) $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS)) $(CFL)
+$(vobjs): KBUILD_AFLAGS += -DBUILD_VDSO
+
+#
+# vDSO code runs in userspace and -pg doesn't help with profiling anyway.
+#
+CFLAGS_REMOVE_vclock_gettime.o = -pg
+CFLAGS_REMOVE_vdso32/vclock_gettime.o = -pg
+CFLAGS_REMOVE_vgetcpu.o = -pg
+CFLAGS_REMOVE_vdso32/vgetcpu.o = -pg
+CFLAGS_REMOVE_vsgx.o = -pg
+CFLAGS_REMOVE_vgetrandom.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 = -m elf32_x86_64 -soname linux-vdso.so.1 \
+			   -z max-page-size=4096
+
+# x32-rebranded versions
+vobjx32s-y := $(vobjs-y:.o=-x32.o)
+
+# same thing, but in the output directory
+vobjx32s := $(addprefix $(obj)/, $(vobjx32s-y))
+
+# 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 --remove-section __ex_table
+$(obj)/%.so: $(obj)/%.so.dbg FORCE
+	$(call if_changed,objcopy)
+
+$(obj)/vdsox32.so.dbg: $(obj)/vdsox32.lds $(vobjx32s) FORCE
+	$(call if_changed,vdso_and_check)
+
+CPPFLAGS_vdso32/vdso32.lds = $(CPPFLAGS_vdso.lds)
+VDSO_LDFLAGS_vdso32.lds = -m elf_i386 -soname linux-gate.so.1
+
+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 := $(filter-out $(RANDSTRUCT_CFLAGS),$(KBUILD_CFLAGS_32))
+KBUILD_CFLAGS_32 := $(filter-out $(KSTACK_ERASE_CFLAGS),$(KBUILD_CFLAGS_32))
+KBUILD_CFLAGS_32 := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS_32))
+KBUILD_CFLAGS_32 := $(filter-out $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS_32))
+KBUILD_CFLAGS_32 := $(filter-out $(CC_FLAGS_LTO),$(KBUILD_CFLAGS_32))
+KBUILD_CFLAGS_32 := $(filter-out $(CC_FLAGS_CFI),$(KBUILD_CFLAGS_32))
+KBUILD_CFLAGS_32 := $(filter-out $(PADDING_CFLAGS),$(KBUILD_CFLAGS_32))
+KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic
+KBUILD_CFLAGS_32 += -fno-stack-protector
+KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls)
+KBUILD_CFLAGS_32 += -fno-omit-frame-pointer
+KBUILD_CFLAGS_32 += -DDISABLE_BRANCH_PROFILING
+KBUILD_CFLAGS_32 += -DBUILD_VDSO
+
+ifdef CONFIG_MITIGATION_RETPOLINE
+ifneq ($(RETPOLINE_VDSO_CFLAGS),)
+  KBUILD_CFLAGS_32 += $(RETPOLINE_VDSO_CFLAGS)
+endif
+endif
+
+$(obj)/vdso32.so.dbg: KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
+
+$(obj)/vdso32.so.dbg: $(obj)/vdso32/vdso32.lds $(vobjs32) FORCE
+	$(call if_changed,vdso_and_check)
+
+#
+# The DSO images are built using a special linker script.
+#
+quiet_cmd_vdso = VDSO    $@
+      cmd_vdso = $(LD) -o $@ \
+		       $(VDSO_LDFLAGS) $(VDSO_LDFLAGS_$(filter %.lds,$(^F))) \
+		       -T $(filter %.lds,$^) $(filter %.o,$^)
+
+VDSO_LDFLAGS = -shared --hash-style=both --build-id=sha1 --no-undefined \
+	$(call ld-option, --eh-frame-hdr) -Bsymbolic -z noexecstack
+
+quiet_cmd_vdso_and_check = VDSO    $@
+      cmd_vdso_and_check = $(cmd_vdso); $(cmd_vdso_check)