Will Deacon d27865279f Merge branch 'for-next/bti' into for-next/core
Support for Branch Target Identification (BTI) in user and kernel
(Mark Brown and others)
* for-next/bti: (39 commits)
  arm64: vdso: Fix CFI directives in sigreturn trampoline
  arm64: vdso: Don't prefix sigreturn trampoline with a BTI C instruction
  arm64: bti: Fix support for userspace only BTI
  arm64: kconfig: Update and comment GCC version check for kernel BTI
  arm64: vdso: Map the vDSO text with guarded pages when built for BTI
  arm64: vdso: Force the vDSO to be linked as BTI when built for BTI
  arm64: vdso: Annotate for BTI
  arm64: asm: Provide a mechanism for generating ELF note for BTI
  arm64: bti: Provide Kconfig for kernel mode BTI
  arm64: mm: Mark executable text as guarded pages
  arm64: bpf: Annotate JITed code for BTI
  arm64: Set GP bit in kernel page tables to enable BTI for the kernel
  arm64: asm: Override SYM_FUNC_START when building the kernel with BTI
  arm64: bti: Support building kernel C code using BTI
  arm64: Document why we enable PAC support for leaf functions
  arm64: insn: Report PAC and BTI instructions as skippable
  arm64: insn: Don't assume unrecognized HINTs are skippable
  arm64: insn: Provide a better name for aarch64_insn_is_nop()
  arm64: insn: Add constants for new HINT instruction decode
  arm64: Disable old style assembly annotations
  ...
2020-05-28 18:00:51 +01:00

92 lines
2.7 KiB
Makefile

# SPDX-License-Identifier: GPL-2.0
#
# Building a vDSO image for AArch64.
#
# Author: Will Deacon <will.deacon@arm.com>
# Heavily based on the vDSO Makefiles for other archs.
#
# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before
# the inclusion of generic Makefile.
ARCH_REL_TYPE_ABS := R_AARCH64_JUMP_SLOT|R_AARCH64_GLOB_DAT|R_AARCH64_ABS64
include $(srctree)/lib/vdso/Makefile
obj-vdso := vgettimeofday.o note.o sigreturn.o
# Build rules
targets := $(obj-vdso) vdso.so vdso.so.dbg
obj-vdso := $(addprefix $(obj)/, $(obj-vdso))
btildflags-$(CONFIG_ARM64_BTI_KERNEL) += -z force-bti
# -Bsymbolic has been added for consistency with arm, the compat vDSO and
# potential future proofing if we end up with internal calls to the exported
# routines, as x86 does (see 6f121e548f83 ("x86, vdso: Reimplement vdso.so
# preparation in build-time C")).
ldflags-y := -shared -nostdlib -soname=linux-vdso.so.1 --hash-style=sysv \
-Bsymbolic --eh-frame-hdr --build-id -n $(btildflags-y) -T
ccflags-y := -fno-common -fno-builtin -fno-stack-protector -ffixed-x18
ccflags-y += -DDISABLE_BRANCH_PROFILING
CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os
KBUILD_CFLAGS += $(DISABLE_LTO)
KASAN_SANITIZE := n
UBSAN_SANITIZE := n
OBJECT_FILES_NON_STANDARD := y
KCOV_INSTRUMENT := n
CFLAGS_vgettimeofday.o = -O2 -mcmodel=tiny
ifneq ($(c-gettimeofday-y),)
CFLAGS_vgettimeofday.o += -include $(c-gettimeofday-y)
endif
# Clang versions less than 8 do not support -mcmodel=tiny
ifeq ($(CONFIG_CC_IS_CLANG), y)
ifeq ($(shell test $(CONFIG_CLANG_VERSION) -lt 80000; echo $$?),0)
CFLAGS_REMOVE_vgettimeofday.o += -mcmodel=tiny
endif
endif
# Disable gcov profiling for VDSO code
GCOV_PROFILE := n
obj-y += vdso.o
extra-y += vdso.lds
CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
# Force dependency (incbin is bad)
$(obj)/vdso.o : $(obj)/vdso.so
# Link rule for the .so file, .lds has to be first
$(obj)/vdso.so.dbg: $(obj)/vdso.lds $(obj-vdso) FORCE
$(call if_changed,vdsold_and_vdso_check)
# Strip rule for the .so file
$(obj)/%.so: OBJCOPYFLAGS := -S
$(obj)/%.so: $(obj)/%.so.dbg FORCE
$(call if_changed,objcopy)
# Generate VDSO offsets using helper script
gen-vdsosym := $(srctree)/$(src)/gen_vdso_offsets.sh
quiet_cmd_vdsosym = VDSOSYM $@
cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@
include/generated/vdso-offsets.h: $(obj)/vdso.so.dbg FORCE
$(call if_changed,vdsosym)
# Actual build commands
quiet_cmd_vdsold_and_vdso_check = LD $@
cmd_vdsold_and_vdso_check = $(cmd_ld); $(cmd_vdso_check)
# Install commands for the unstripped file
quiet_cmd_vdso_install = INSTALL $@
cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/$@
vdso.so: $(obj)/vdso.so.dbg
@mkdir -p $(MODLIB)/vdso
$(call cmd,vdso_install)
vdso_install: vdso.so