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arm64: vdso32: Fix broken compat vDSO build warnings 

The .config file and the generated include/config/auto.conf can
end up out of sync after a set of commands since
CONFIG_CROSS_COMPILE_COMPAT_VDSO is not updated correctly.

The sequence can be reproduced as follows:

$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- defconfig
[...]
$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- menuconfig
[set CONFIG_CROSS_COMPILE_COMPAT_VDSO="arm-linux-gnueabihf-"]
$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu-

Which results in:

arch/arm64/Makefile:62: CROSS_COMPILE_COMPAT not defined or empty,
the compat vDSO will not be built

even though the compat vDSO has been built:

$ file arch/arm64/kernel/vdso32/vdso.so
arch/arm64/kernel/vdso32/vdso.so: ELF 32-bit LSB pie executable, ARM,
EABI5 version 1 (SYSV), dynamically linked,
BuildID[sha1]=c67f6c786f2d2d6f86c71f708595594aa25247f6, stripped

A similar case that involves changing the configuration parameter
multiple times can be reconducted to the same family of problems.

Remove the use of CONFIG_CROSS_COMPILE_COMPAT_VDSO altogether and
instead rely on the cross-compiler prefix coming from the environment
via CROSS_COMPILE_COMPAT, much like we do for the rest of the kernel.

Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Will Deacon <will@kernel.org>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
alistair/sunxi64-5.4-dsi
Vincenzo Frascino 2019-10-03 18:48:33 +01:00 committed by Will Deacon
parent 308c515617
commit e0de01aafc
3 changed files with 6 additions and 16 deletions
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2
arch/arm64/Kconfig
View File

@ -110,7 +110,7 @@ config ARM64
select GENERIC_STRNLEN_USER
select GENERIC_TIME_VSYSCALL
select GENERIC_GETTIMEOFDAY
select GENERIC_COMPAT_VDSO if (!CPU_BIG_ENDIAN && COMPAT)
select GENERIC_COMPAT_VDSO if (!CPU_BIG_ENDIAN && COMPAT && "$(CROSS_COMPILE_COMPAT)" != "")
select HANDLE_DOMAIN_IRQ
select HARDIRQS_SW_RESEND
select HAVE_PCI

18
arch/arm64/Makefile
View File

@ -53,20 +53,12 @@ $(warning Detected assembler with broken .inst; disassembly will be unreliable)
endif
endif
ifeq ($(CONFIG_GENERIC_COMPAT_VDSO), y)
CROSS_COMPILE_COMPAT ?= $(CONFIG_CROSS_COMPILE_COMPAT_VDSO:"%"=%)
COMPATCC ?= $(CROSS_COMPILE_COMPAT)gcc
export COMPATCC
ifeq ($(CONFIG_CC_IS_CLANG), y)
$(warning CROSS_COMPILE_COMPAT is clang, the compat vDSO will not be built)
else ifeq ($(strip $(CROSS_COMPILE_COMPAT)),)
$(warning CROSS_COMPILE_COMPAT not defined or empty, the compat vDSO will not be built)
else ifeq ($(shell which $(CROSS_COMPILE_COMPAT)gcc 2> /dev/null),)
$(error $(CROSS_COMPILE_COMPAT)gcc not found, check CROSS_COMPILE_COMPAT)
else
export CROSS_COMPILE_COMPAT
export CONFIG_COMPAT_VDSO := y
compat_vdso := -DCONFIG_COMPAT_VDSO=1
endif
ifeq ($(CONFIG_GENERIC_COMPAT_VDSO), y)
export CONFIG_COMPAT_VDSO := y
compat_vdso := -DCONFIG_COMPAT_VDSO=1
endif
KBUILD_CFLAGS += -mgeneral-regs-only $(lseinstr) $(brokengasinst) \

2
arch/arm64/kernel/vdso32/Makefile
View File

@ -8,8 +8,6 @@
ARCH_REL_TYPE_ABS := R_ARM_JUMP_SLOT|R_ARM_GLOB_DAT|R_ARM_ABS32
include $(srctree)/lib/vdso/Makefile
COMPATCC := $(CROSS_COMPILE_COMPAT)gcc
# Same as cc-*option, but using COMPATCC instead of CC
cc32-option = $(call try-run,\
$(COMPATCC) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2))