625412c210
Allow the compat vdso (32b) to be compiled as either THUMB2 (default) or
ARM.
For THUMB2, the register r7 is reserved for the frame pointer, but
code in arch/arm64/include/asm/vdso/compat_gettimeofday.h
uses r7. Explicitly set -fomit-frame-pointer, since unwinding through
interworked THUMB2 and ARM is unreliable anyways. See also how
CONFIG_UNWINDER_FRAME_POINTER cannot be selected for
CONFIG_THUMB2_KERNEL for ARCH=arm.
This also helps toolchains that differ in their implicit value if the
choice of -f{no-}omit-frame-pointer is left unspecified, to not error on
the use of r7.
2019 Q4 ARM AAPCS seeks to standardize the use of r11 as the reserved
frame pointer register, but no production compiler that can compile the
Linux kernel currently implements this. We're actively discussing such
a transition with ARM toolchain developers currently.
Reported-by: Luis Lozano <llozano@google.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Manoj Gupta <manojgupta@google.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Stephen Boyd <swboyd@google.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Dave Martin <Dave.Martin@arm.com>
Link: https://static.docs.arm.com/ihi0042/i/aapcs32.pdf
Link: https://bugs.chromium.org/p/chromium/issues/detail?id=1084372
Link: https://lore.kernel.org/r/20200608205711.109418-1-ndesaulniers@google.com
Signed-off-by: Will Deacon <will@kernel.org>
220 lines
7.9 KiB
Makefile
220 lines
7.9 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0
|
|
#
|
|
# Makefile for vdso32
|
|
#
|
|
|
|
# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before
|
|
# the inclusion of generic Makefile.
|
|
ARCH_REL_TYPE_ABS := R_ARM_JUMP_SLOT|R_ARM_GLOB_DAT|R_ARM_ABS32
|
|
include $(srctree)/lib/vdso/Makefile
|
|
|
|
# Same as cc-*option, but using CC_COMPAT instead of CC
|
|
ifeq ($(CONFIG_CC_IS_CLANG), y)
|
|
COMPAT_GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE_COMPAT)elfedit))
|
|
COMPAT_GCC_TOOLCHAIN := $(realpath $(COMPAT_GCC_TOOLCHAIN_DIR)/..)
|
|
|
|
CC_COMPAT_CLANG_FLAGS := --target=$(notdir $(CROSS_COMPILE_COMPAT:%-=%))
|
|
CC_COMPAT_CLANG_FLAGS += --prefix=$(COMPAT_GCC_TOOLCHAIN_DIR)
|
|
CC_COMPAT_CLANG_FLAGS += -no-integrated-as -Qunused-arguments
|
|
ifneq ($(COMPAT_GCC_TOOLCHAIN),)
|
|
CC_COMPAT_CLANG_FLAGS += --gcc-toolchain=$(COMPAT_GCC_TOOLCHAIN)
|
|
endif
|
|
|
|
CC_COMPAT ?= $(CC)
|
|
CC_COMPAT += $(CC_COMPAT_CLANG_FLAGS)
|
|
else
|
|
CC_COMPAT ?= $(CROSS_COMPILE_COMPAT)gcc
|
|
endif
|
|
|
|
cc32-option = $(call try-run,\
|
|
$(CC_COMPAT) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2))
|
|
cc32-disable-warning = $(call try-run,\
|
|
$(CC_COMPAT) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1)))
|
|
cc32-ldoption = $(call try-run,\
|
|
$(CC_COMPAT) $(1) -nostdlib -x c /dev/null -o "$$TMP",$(1),$(2))
|
|
cc32-as-instr = $(call try-run,\
|
|
printf "%b\n" "$(1)" | $(CC_COMPAT) $(VDSO_AFLAGS) -c -x assembler -o "$$TMP" -,$(2),$(3))
|
|
|
|
# We cannot use the global flags to compile the vDSO files, the main reason
|
|
# being that the 32-bit compiler may be older than the main (64-bit) compiler
|
|
# and therefore may not understand flags set using $(cc-option ...). Besides,
|
|
# arch-specific options should be taken from the arm Makefile instead of the
|
|
# arm64 one.
|
|
# As a result we set our own flags here.
|
|
|
|
# KBUILD_CPPFLAGS and NOSTDINC_FLAGS from top-level Makefile
|
|
VDSO_CPPFLAGS := -D__KERNEL__ -nostdinc -isystem $(shell $(CC_COMPAT) -print-file-name=include)
|
|
VDSO_CPPFLAGS += $(LINUXINCLUDE)
|
|
|
|
# Common C and assembly flags
|
|
# From top-level Makefile
|
|
VDSO_CAFLAGS := $(VDSO_CPPFLAGS)
|
|
ifneq ($(shell $(CC_COMPAT) --version 2>&1 | head -n 1 | grep clang),)
|
|
VDSO_CAFLAGS += --target=$(notdir $(CROSS_COMPILE_COMPAT:%-=%))
|
|
endif
|
|
|
|
VDSO_CAFLAGS += $(call cc32-option,-fno-PIE)
|
|
ifdef CONFIG_DEBUG_INFO
|
|
VDSO_CAFLAGS += -g
|
|
endif
|
|
|
|
# From arm Makefile
|
|
VDSO_CAFLAGS += $(call cc32-option,-fno-dwarf2-cfi-asm)
|
|
VDSO_CAFLAGS += -mabi=aapcs-linux -mfloat-abi=soft
|
|
ifeq ($(CONFIG_CPU_BIG_ENDIAN), y)
|
|
VDSO_CAFLAGS += -mbig-endian
|
|
else
|
|
VDSO_CAFLAGS += -mlittle-endian
|
|
endif
|
|
|
|
# From arm vDSO Makefile
|
|
VDSO_CAFLAGS += -fPIC -fno-builtin -fno-stack-protector
|
|
VDSO_CAFLAGS += -DDISABLE_BRANCH_PROFILING
|
|
|
|
|
|
# Try to compile for ARMv8. If the compiler is too old and doesn't support it,
|
|
# fall back to v7. There is no easy way to check for what architecture the code
|
|
# is being compiled, so define a macro specifying that (see arch/arm/Makefile).
|
|
VDSO_CAFLAGS += $(call cc32-option,-march=armv8-a -D__LINUX_ARM_ARCH__=8,\
|
|
-march=armv7-a -D__LINUX_ARM_ARCH__=7)
|
|
|
|
VDSO_CFLAGS := $(VDSO_CAFLAGS)
|
|
VDSO_CFLAGS += -DENABLE_COMPAT_VDSO=1
|
|
# KBUILD_CFLAGS from top-level Makefile
|
|
VDSO_CFLAGS += -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
|
|
-fno-strict-aliasing -fno-common \
|
|
-Werror-implicit-function-declaration \
|
|
-Wno-format-security \
|
|
-std=gnu89
|
|
VDSO_CFLAGS += -O2
|
|
# Some useful compiler-dependent flags from top-level Makefile
|
|
VDSO_CFLAGS += $(call cc32-option,-Wdeclaration-after-statement,)
|
|
VDSO_CFLAGS += $(call cc32-option,-Wno-pointer-sign)
|
|
VDSO_CFLAGS += $(call cc32-option,-fno-strict-overflow)
|
|
VDSO_CFLAGS += $(call cc32-option,-Werror=strict-prototypes)
|
|
VDSO_CFLAGS += $(call cc32-option,-Werror=date-time)
|
|
VDSO_CFLAGS += $(call cc32-option,-Werror=incompatible-pointer-types)
|
|
|
|
# The 32-bit compiler does not provide 128-bit integers, which are used in
|
|
# some headers that are indirectly included from the vDSO code.
|
|
# This hack makes the compiler happy and should trigger a warning/error if
|
|
# variables of such type are referenced.
|
|
VDSO_CFLAGS += -D__uint128_t='void*'
|
|
# Silence some warnings coming from headers that operate on long's
|
|
# (on GCC 4.8 or older, there is unfortunately no way to silence this warning)
|
|
VDSO_CFLAGS += $(call cc32-disable-warning,shift-count-overflow)
|
|
VDSO_CFLAGS += -Wno-int-to-pointer-cast
|
|
|
|
# Compile as THUMB2 or ARM. Unwinding via frame-pointers in THUMB2 is
|
|
# unreliable.
|
|
ifeq ($(CONFIG_THUMB2_COMPAT_VDSO), y)
|
|
VDSO_CFLAGS += -mthumb -fomit-frame-pointer
|
|
else
|
|
VDSO_CFLAGS += -marm
|
|
endif
|
|
|
|
VDSO_AFLAGS := $(VDSO_CAFLAGS)
|
|
VDSO_AFLAGS += -D__ASSEMBLY__
|
|
|
|
# Check for binutils support for dmb ishld
|
|
dmbinstr := $(call cc32-as-instr,dmb ishld,-DCONFIG_AS_DMB_ISHLD=1)
|
|
|
|
VDSO_CFLAGS += $(dmbinstr)
|
|
VDSO_AFLAGS += $(dmbinstr)
|
|
|
|
VDSO_LDFLAGS := $(VDSO_CPPFLAGS)
|
|
# From arm vDSO Makefile
|
|
VDSO_LDFLAGS += -Wl,-Bsymbolic -Wl,--no-undefined -Wl,-soname=linux-vdso.so.1
|
|
VDSO_LDFLAGS += -Wl,-z,max-page-size=4096 -Wl,-z,common-page-size=4096
|
|
VDSO_LDFLAGS += -nostdlib -shared -mfloat-abi=soft
|
|
VDSO_LDFLAGS += -Wl,--hash-style=sysv
|
|
VDSO_LDFLAGS += -Wl,--build-id
|
|
VDSO_LDFLAGS += $(call cc32-ldoption,-fuse-ld=bfd)
|
|
|
|
|
|
# Borrow vdsomunge.c from the arm vDSO
|
|
# We have to use a relative path because scripts/Makefile.host prefixes
|
|
# $(hostprogs) with $(obj)
|
|
munge := ../../../arm/vdso/vdsomunge
|
|
hostprogs := $(munge)
|
|
|
|
c-obj-vdso := note.o
|
|
c-obj-vdso-gettimeofday := vgettimeofday.o
|
|
asm-obj-vdso := sigreturn.o
|
|
|
|
ifneq ($(c-gettimeofday-y),)
|
|
VDSO_CFLAGS_gettimeofday_o += -include $(c-gettimeofday-y)
|
|
endif
|
|
|
|
VDSO_CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os
|
|
|
|
# Build rules
|
|
targets := $(c-obj-vdso) $(c-obj-vdso-gettimeofday) $(asm-obj-vdso) vdso.so vdso.so.dbg vdso.so.raw
|
|
c-obj-vdso := $(addprefix $(obj)/, $(c-obj-vdso))
|
|
c-obj-vdso-gettimeofday := $(addprefix $(obj)/, $(c-obj-vdso-gettimeofday))
|
|
asm-obj-vdso := $(addprefix $(obj)/, $(asm-obj-vdso))
|
|
obj-vdso := $(c-obj-vdso) $(c-obj-vdso-gettimeofday) $(asm-obj-vdso)
|
|
|
|
obj-y += vdso.o
|
|
extra-y += vdso.lds
|
|
CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
|
|
|
|
# Force dependency (vdso.s includes vdso.so through incbin)
|
|
$(obj)/vdso.o: $(obj)/vdso.so
|
|
|
|
include/generated/vdso32-offsets.h: $(obj)/vdso.so.dbg FORCE
|
|
$(call if_changed,vdsosym)
|
|
|
|
# Strip rule for vdso.so
|
|
$(obj)/vdso.so: OBJCOPYFLAGS := -S
|
|
$(obj)/vdso.so: $(obj)/vdso.so.dbg FORCE
|
|
$(call if_changed,objcopy)
|
|
|
|
$(obj)/vdso.so.dbg: $(obj)/vdso.so.raw $(obj)/$(munge) FORCE
|
|
$(call if_changed,vdsomunge)
|
|
|
|
# Link rule for the .so file, .lds has to be first
|
|
$(obj)/vdso.so.raw: $(src)/vdso.lds $(obj-vdso) FORCE
|
|
$(call if_changed,vdsold_and_vdso_check)
|
|
|
|
# Compilation rules for the vDSO sources
|
|
$(c-obj-vdso): %.o: %.c FORCE
|
|
$(call if_changed_dep,vdsocc)
|
|
$(c-obj-vdso-gettimeofday): %.o: %.c FORCE
|
|
$(call if_changed_dep,vdsocc_gettimeofday)
|
|
$(asm-obj-vdso): %.o: %.S FORCE
|
|
$(call if_changed_dep,vdsoas)
|
|
|
|
# Actual build commands
|
|
quiet_cmd_vdsold_and_vdso_check = LD32 $@
|
|
cmd_vdsold_and_vdso_check = $(cmd_vdsold); $(cmd_vdso_check)
|
|
|
|
quiet_cmd_vdsold = LD32 $@
|
|
cmd_vdsold = $(CC_COMPAT) -Wp,-MD,$(depfile) $(VDSO_LDFLAGS) \
|
|
-Wl,-T $(filter %.lds,$^) $(filter %.o,$^) -o $@
|
|
quiet_cmd_vdsocc = CC32 $@
|
|
cmd_vdsocc = $(CC_COMPAT) -Wp,-MD,$(depfile) $(VDSO_CFLAGS) -c -o $@ $<
|
|
quiet_cmd_vdsocc_gettimeofday = CC32 $@
|
|
cmd_vdsocc_gettimeofday = $(CC_COMPAT) -Wp,-MD,$(depfile) $(VDSO_CFLAGS) $(VDSO_CFLAGS_gettimeofday_o) -c -o $@ $<
|
|
quiet_cmd_vdsoas = AS32 $@
|
|
cmd_vdsoas = $(CC_COMPAT) -Wp,-MD,$(depfile) $(VDSO_AFLAGS) -c -o $@ $<
|
|
|
|
quiet_cmd_vdsomunge = MUNGE $@
|
|
cmd_vdsomunge = $(obj)/$(munge) $< $@
|
|
|
|
# Generate vDSO offsets using helper script (borrowed from the 64-bit vDSO)
|
|
gen-vdsosym := $(srctree)/$(src)/../vdso/gen_vdso_offsets.sh
|
|
quiet_cmd_vdsosym = VDSOSYM $@
|
|
# The AArch64 nm should be able to read an AArch32 binary
|
|
cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@
|
|
|
|
# Install commands for the unstripped file
|
|
quiet_cmd_vdso_install = INSTALL $@
|
|
cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/vdso32.so
|
|
|
|
vdso.so: $(obj)/vdso.so.dbg
|
|
@mkdir -p $(MODLIB)/vdso
|
|
$(call cmd,vdso_install)
|
|
|
|
vdso_install: vdso.so
|