2018-01-06 20:16:17

by Martin Kelly

[permalink] [raw]
Subject: [PATCH] tools: fix cross-compile var export

From: Martin Kelly <[email protected]>

Currently in a number of Makefiles, we clobber the CC, LD, and/or STRIP env vars
when cross-compiling, which breaks any additional flags that might be set (such
as sysroot). This easily shows up by using, for instance, a Yocto SDK.

Fix this by more carefully overriding the flags in the way that the perf
Makefile does.

This patch does not fix cross-compile for all the tools (some have other bugs),
but it does appear to fix it for these:

- cgroup
- freefall
- gpio
- hv
- iio
- leds
- spi
- vm
- wmi

Signed-off-by: Martin Kelly <[email protected]>
---
This patch touches multiple subsystems, and there doesn't appear to be a global
tools maintainer, so I sent this to linux-embedded kernel-janitors, and
linux-kbuild. Please let me know if there is a better place for it.

tools/cgroup/Makefile | 1 -
tools/gpio/Makefile | 2 --
tools/hv/Makefile | 1 -
tools/iio/Makefile | 2 --
tools/laptop/freefall/Makefile | 1 -
tools/leds/Makefile | 1 -
tools/perf/Makefile.perf | 6 ------
tools/power/acpi/Makefile.config | 3 ---
tools/scripts/Makefile.include | 18 ++++++++++++++++++
tools/spi/Makefile | 2 --
tools/usb/Makefile | 1 -
tools/vm/Makefile | 1 -
tools/wmi/Makefile | 1 -
13 files changed, 18 insertions(+), 22 deletions(-)

diff --git a/tools/cgroup/Makefile b/tools/cgroup/Makefile
index 860fa151640a..ffca068e4a76 100644
--- a/tools/cgroup/Makefile
+++ b/tools/cgroup/Makefile
@@ -1,7 +1,6 @@
# SPDX-License-Identifier: GPL-2.0
# Makefile for cgroup tools

-CC = $(CROSS_COMPILE)gcc
CFLAGS = -Wall -Wextra

all: cgroup_event_listener
diff --git a/tools/gpio/Makefile b/tools/gpio/Makefile
index 805a2c0cf4cd..240eda014b37 100644
--- a/tools/gpio/Makefile
+++ b/tools/gpio/Makefile
@@ -12,8 +12,6 @@ endif
# (this improves performance and avoids hard-to-debug behaviour);
MAKEFLAGS += -r

-CC = $(CROSS_COMPILE)gcc
-LD = $(CROSS_COMPILE)ld
CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include

ALL_TARGETS := lsgpio gpio-hammer gpio-event-mon
diff --git a/tools/hv/Makefile b/tools/hv/Makefile
index 31503819454d..68c2d7b059b3 100644
--- a/tools/hv/Makefile
+++ b/tools/hv/Makefile
@@ -1,7 +1,6 @@
# SPDX-License-Identifier: GPL-2.0
# Makefile for Hyper-V tools

-CC = $(CROSS_COMPILE)gcc
WARNINGS = -Wall -Wextra
CFLAGS = $(WARNINGS) -g $(shell getconf LFS_CFLAGS)

diff --git a/tools/iio/Makefile b/tools/iio/Makefile
index a08e7a47d6a3..332ed2f6c2c2 100644
--- a/tools/iio/Makefile
+++ b/tools/iio/Makefile
@@ -12,8 +12,6 @@ endif
# (this improves performance and avoids hard-to-debug behaviour);
MAKEFLAGS += -r

-CC = $(CROSS_COMPILE)gcc
-LD = $(CROSS_COMPILE)ld
CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include

ALL_TARGETS := iio_event_monitor lsiio iio_generic_buffer
diff --git a/tools/laptop/freefall/Makefile b/tools/laptop/freefall/Makefile
index 5f758c489a20..b572d94255f6 100644
--- a/tools/laptop/freefall/Makefile
+++ b/tools/laptop/freefall/Makefile
@@ -2,7 +2,6 @@
PREFIX ?= /usr
SBINDIR ?= sbin
INSTALL ?= install
-CC = $(CROSS_COMPILE)gcc

TARGET = freefall

diff --git a/tools/leds/Makefile b/tools/leds/Makefile
index c379af003807..7b6bed13daaa 100644
--- a/tools/leds/Makefile
+++ b/tools/leds/Makefile
@@ -1,7 +1,6 @@
# SPDX-License-Identifier: GPL-2.0
# Makefile for LEDs tools

-CC = $(CROSS_COMPILE)gcc
CFLAGS = -Wall -Wextra -g -I../../include/uapi

all: uledmon led_hw_brightness_mon
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 68cf1360a3f3..3035ce5f6b36 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -144,12 +144,6 @@ define allow-override
$(eval $(1) = $(2)))
endef

-# Allow setting CC and AR and LD, or setting CROSS_COMPILE as a prefix.
-$(call allow-override,CC,$(CROSS_COMPILE)gcc)
-$(call allow-override,AR,$(CROSS_COMPILE)ar)
-$(call allow-override,LD,$(CROSS_COMPILE)ld)
-$(call allow-override,CXX,$(CROSS_COMPILE)g++)
-
LD += $(EXTRA_LDFLAGS)

HOSTCC ?= gcc
diff --git a/tools/power/acpi/Makefile.config b/tools/power/acpi/Makefile.config
index a1883bbb0144..2cccbba64418 100644
--- a/tools/power/acpi/Makefile.config
+++ b/tools/power/acpi/Makefile.config
@@ -56,9 +56,6 @@ INSTALL_SCRIPT = ${INSTALL_PROGRAM}
# to compile vs uClibc, that can be done here as well.
CROSS = #/usr/i386-linux-uclibc/usr/bin/i386-uclibc-
CROSS_COMPILE ?= $(CROSS)
-CC = $(CROSS_COMPILE)gcc
-LD = $(CROSS_COMPILE)gcc
-STRIP = $(CROSS_COMPILE)strip
HOSTCC = gcc

# check if compiler option is supported
diff --git a/tools/scripts/Makefile.include b/tools/scripts/Makefile.include
index 3fab179b1aba..09b2d0f07f66 100644
--- a/tools/scripts/Makefile.include
+++ b/tools/scripts/Makefile.include
@@ -42,6 +42,24 @@ EXTRA_WARNINGS += -Wformat

CC_NO_CLANG := $(shell $(CC) -dM -E -x c /dev/null | grep -Fq "__clang__"; echo $$?)

+# Makefiles suck: This macro sets a default value of $(2) for the
+# variable named by $(1), unless the variable has been set by
+# environment or command line. This is necessary for CC and AR
+# because make sets default values, so the simpler ?= approach
+# won't work as expected.
+define allow-override
+ $(if $(or $(findstring environment,$(origin $(1))),\
+ $(findstring command line,$(origin $(1)))),,\
+ $(eval $(1) = $(2)))
+endef
+
+# Allow setting various cross-compile vars or setting CROSS_COMPILE as a prefix.
+$(call allow-override,CC,$(CROSS_COMPILE)gcc)
+$(call allow-override,AR,$(CROSS_COMPILE)ar)
+$(call allow-override,LD,$(CROSS_COMPILE)ld)
+$(call allow-override,CXX,$(CROSS_COMPILE)g++)
+$(call allow-override,CXX,$(CROSS_COMPILE)strip)
+
ifeq ($(CC_NO_CLANG), 1)
EXTRA_WARNINGS += -Wstrict-aliasing=3
endif
diff --git a/tools/spi/Makefile b/tools/spi/Makefile
index 90615e10c79a..815d15589177 100644
--- a/tools/spi/Makefile
+++ b/tools/spi/Makefile
@@ -11,8 +11,6 @@ endif
# (this improves performance and avoids hard-to-debug behaviour);
MAKEFLAGS += -r

-CC = $(CROSS_COMPILE)gcc
-LD = $(CROSS_COMPILE)ld
CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include

ALL_TARGETS := spidev_test spidev_fdx
diff --git a/tools/usb/Makefile b/tools/usb/Makefile
index 4e6506078494..01d758d73b6d 100644
--- a/tools/usb/Makefile
+++ b/tools/usb/Makefile
@@ -1,7 +1,6 @@
# SPDX-License-Identifier: GPL-2.0
# Makefile for USB tools

-CC = $(CROSS_COMPILE)gcc
PTHREAD_LIBS = -lpthread
WARNINGS = -Wall -Wextra
CFLAGS = $(WARNINGS) -g -I../include
diff --git a/tools/vm/Makefile b/tools/vm/Makefile
index be320b905ea7..20f6cf04377f 100644
--- a/tools/vm/Makefile
+++ b/tools/vm/Makefile
@@ -6,7 +6,6 @@ TARGETS=page-types slabinfo page_owner_sort
LIB_DIR = ../lib/api
LIBS = $(LIB_DIR)/libapi.a

-CC = $(CROSS_COMPILE)gcc
CFLAGS = -Wall -Wextra -I../lib/
LDFLAGS = $(LIBS)

diff --git a/tools/wmi/Makefile b/tools/wmi/Makefile
index e664f1167388..e0e87239126b 100644
--- a/tools/wmi/Makefile
+++ b/tools/wmi/Makefile
@@ -2,7 +2,6 @@ PREFIX ?= /usr
SBINDIR ?= sbin
INSTALL ?= install
CFLAGS += -D__EXPORTED_HEADERS__ -I../../include/uapi -I../../include
-CC = $(CROSS_COMPILE)gcc

TARGET = dell-smbios-example

--
2.11.0


2018-01-07 16:12:27

by Paul Gortmaker

[permalink] [raw]
Subject: Re: [PATCH] tools: fix cross-compile var export

[[PATCH] tools: fix cross-compile var export] On 06/01/2018 (Sat 12:16) Martin Kelly wrote:

> From: Martin Kelly <[email protected]>
>
> Currently in a number of Makefiles, we clobber the CC, LD, and/or STRIP env vars
> when cross-compiling, which breaks any additional flags that might be set (such
> as sysroot). This easily shows up by using, for instance, a Yocto SDK.
>
> Fix this by more carefully overriding the flags in the way that the perf
> Makefile does.
>
> This patch does not fix cross-compile for all the tools (some have other bugs),
> but it does appear to fix it for these:
>
> - cgroup
> - freefall
> - gpio
> - hv
> - iio
> - leds
> - spi
> - vm
> - wmi
>
> Signed-off-by: Martin Kelly <[email protected]>
> ---
> This patch touches multiple subsystems, and there doesn't appear to be a global
> tools maintainer, so I sent this to linux-embedded kernel-janitors, and
> linux-kbuild. Please let me know if there is a better place for it.

I think you will have better luck if you go subsystem by subsystem, e.g.
send gpio change to gpio maintainer, usb change to usb maintainer and so
on. In addition, you'll want to try and understand/explain why those
lines were added in the 1st place and how it won't break other existing
use cases by removing them. Maybe "git blame" will help for that...

P.
--

>
> tools/cgroup/Makefile | 1 -
> tools/gpio/Makefile | 2 --
> tools/hv/Makefile | 1 -
> tools/iio/Makefile | 2 --
> tools/laptop/freefall/Makefile | 1 -
> tools/leds/Makefile | 1 -
> tools/perf/Makefile.perf | 6 ------
> tools/power/acpi/Makefile.config | 3 ---
> tools/scripts/Makefile.include | 18 ++++++++++++++++++
> tools/spi/Makefile | 2 --
> tools/usb/Makefile | 1 -
> tools/vm/Makefile | 1 -
> tools/wmi/Makefile | 1 -
> 13 files changed, 18 insertions(+), 22 deletions(-)
>
> diff --git a/tools/cgroup/Makefile b/tools/cgroup/Makefile
> index 860fa151640a..ffca068e4a76 100644
> --- a/tools/cgroup/Makefile
> +++ b/tools/cgroup/Makefile
> @@ -1,7 +1,6 @@
> # SPDX-License-Identifier: GPL-2.0
> # Makefile for cgroup tools
>
> -CC = $(CROSS_COMPILE)gcc
> CFLAGS = -Wall -Wextra
>
> all: cgroup_event_listener
> diff --git a/tools/gpio/Makefile b/tools/gpio/Makefile
> index 805a2c0cf4cd..240eda014b37 100644
> --- a/tools/gpio/Makefile
> +++ b/tools/gpio/Makefile
> @@ -12,8 +12,6 @@ endif
> # (this improves performance and avoids hard-to-debug behaviour);
> MAKEFLAGS += -r
>
> -CC = $(CROSS_COMPILE)gcc
> -LD = $(CROSS_COMPILE)ld
> CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include
>
> ALL_TARGETS := lsgpio gpio-hammer gpio-event-mon
> diff --git a/tools/hv/Makefile b/tools/hv/Makefile
> index 31503819454d..68c2d7b059b3 100644
> --- a/tools/hv/Makefile
> +++ b/tools/hv/Makefile
> @@ -1,7 +1,6 @@
> # SPDX-License-Identifier: GPL-2.0
> # Makefile for Hyper-V tools
>
> -CC = $(CROSS_COMPILE)gcc
> WARNINGS = -Wall -Wextra
> CFLAGS = $(WARNINGS) -g $(shell getconf LFS_CFLAGS)
>
> diff --git a/tools/iio/Makefile b/tools/iio/Makefile
> index a08e7a47d6a3..332ed2f6c2c2 100644
> --- a/tools/iio/Makefile
> +++ b/tools/iio/Makefile
> @@ -12,8 +12,6 @@ endif
> # (this improves performance and avoids hard-to-debug behaviour);
> MAKEFLAGS += -r
>
> -CC = $(CROSS_COMPILE)gcc
> -LD = $(CROSS_COMPILE)ld
> CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include
>
> ALL_TARGETS := iio_event_monitor lsiio iio_generic_buffer
> diff --git a/tools/laptop/freefall/Makefile b/tools/laptop/freefall/Makefile
> index 5f758c489a20..b572d94255f6 100644
> --- a/tools/laptop/freefall/Makefile
> +++ b/tools/laptop/freefall/Makefile
> @@ -2,7 +2,6 @@
> PREFIX ?= /usr
> SBINDIR ?= sbin
> INSTALL ?= install
> -CC = $(CROSS_COMPILE)gcc
>
> TARGET = freefall
>
> diff --git a/tools/leds/Makefile b/tools/leds/Makefile
> index c379af003807..7b6bed13daaa 100644
> --- a/tools/leds/Makefile
> +++ b/tools/leds/Makefile
> @@ -1,7 +1,6 @@
> # SPDX-License-Identifier: GPL-2.0
> # Makefile for LEDs tools
>
> -CC = $(CROSS_COMPILE)gcc
> CFLAGS = -Wall -Wextra -g -I../../include/uapi
>
> all: uledmon led_hw_brightness_mon
> diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
> index 68cf1360a3f3..3035ce5f6b36 100644
> --- a/tools/perf/Makefile.perf
> +++ b/tools/perf/Makefile.perf
> @@ -144,12 +144,6 @@ define allow-override
> $(eval $(1) = $(2)))
> endef
>
> -# Allow setting CC and AR and LD, or setting CROSS_COMPILE as a prefix.
> -$(call allow-override,CC,$(CROSS_COMPILE)gcc)
> -$(call allow-override,AR,$(CROSS_COMPILE)ar)
> -$(call allow-override,LD,$(CROSS_COMPILE)ld)
> -$(call allow-override,CXX,$(CROSS_COMPILE)g++)
> -
> LD += $(EXTRA_LDFLAGS)
>
> HOSTCC ?= gcc
> diff --git a/tools/power/acpi/Makefile.config b/tools/power/acpi/Makefile.config
> index a1883bbb0144..2cccbba64418 100644
> --- a/tools/power/acpi/Makefile.config
> +++ b/tools/power/acpi/Makefile.config
> @@ -56,9 +56,6 @@ INSTALL_SCRIPT = ${INSTALL_PROGRAM}
> # to compile vs uClibc, that can be done here as well.
> CROSS = #/usr/i386-linux-uclibc/usr/bin/i386-uclibc-
> CROSS_COMPILE ?= $(CROSS)
> -CC = $(CROSS_COMPILE)gcc
> -LD = $(CROSS_COMPILE)gcc
> -STRIP = $(CROSS_COMPILE)strip
> HOSTCC = gcc
>
> # check if compiler option is supported
> diff --git a/tools/scripts/Makefile.include b/tools/scripts/Makefile.include
> index 3fab179b1aba..09b2d0f07f66 100644
> --- a/tools/scripts/Makefile.include
> +++ b/tools/scripts/Makefile.include
> @@ -42,6 +42,24 @@ EXTRA_WARNINGS += -Wformat
>
> CC_NO_CLANG := $(shell $(CC) -dM -E -x c /dev/null | grep -Fq "__clang__"; echo $$?)
>
> +# Makefiles suck: This macro sets a default value of $(2) for the
> +# variable named by $(1), unless the variable has been set by
> +# environment or command line. This is necessary for CC and AR
> +# because make sets default values, so the simpler ?= approach
> +# won't work as expected.
> +define allow-override
> + $(if $(or $(findstring environment,$(origin $(1))),\
> + $(findstring command line,$(origin $(1)))),,\
> + $(eval $(1) = $(2)))
> +endef
> +
> +# Allow setting various cross-compile vars or setting CROSS_COMPILE as a prefix.
> +$(call allow-override,CC,$(CROSS_COMPILE)gcc)
> +$(call allow-override,AR,$(CROSS_COMPILE)ar)
> +$(call allow-override,LD,$(CROSS_COMPILE)ld)
> +$(call allow-override,CXX,$(CROSS_COMPILE)g++)
> +$(call allow-override,CXX,$(CROSS_COMPILE)strip)
> +
> ifeq ($(CC_NO_CLANG), 1)
> EXTRA_WARNINGS += -Wstrict-aliasing=3
> endif
> diff --git a/tools/spi/Makefile b/tools/spi/Makefile
> index 90615e10c79a..815d15589177 100644
> --- a/tools/spi/Makefile
> +++ b/tools/spi/Makefile
> @@ -11,8 +11,6 @@ endif
> # (this improves performance and avoids hard-to-debug behaviour);
> MAKEFLAGS += -r
>
> -CC = $(CROSS_COMPILE)gcc
> -LD = $(CROSS_COMPILE)ld
> CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include
>
> ALL_TARGETS := spidev_test spidev_fdx
> diff --git a/tools/usb/Makefile b/tools/usb/Makefile
> index 4e6506078494..01d758d73b6d 100644
> --- a/tools/usb/Makefile
> +++ b/tools/usb/Makefile
> @@ -1,7 +1,6 @@
> # SPDX-License-Identifier: GPL-2.0
> # Makefile for USB tools
>
> -CC = $(CROSS_COMPILE)gcc
> PTHREAD_LIBS = -lpthread
> WARNINGS = -Wall -Wextra
> CFLAGS = $(WARNINGS) -g -I../include
> diff --git a/tools/vm/Makefile b/tools/vm/Makefile
> index be320b905ea7..20f6cf04377f 100644
> --- a/tools/vm/Makefile
> +++ b/tools/vm/Makefile
> @@ -6,7 +6,6 @@ TARGETS=page-types slabinfo page_owner_sort
> LIB_DIR = ../lib/api
> LIBS = $(LIB_DIR)/libapi.a
>
> -CC = $(CROSS_COMPILE)gcc
> CFLAGS = -Wall -Wextra -I../lib/
> LDFLAGS = $(LIBS)
>
> diff --git a/tools/wmi/Makefile b/tools/wmi/Makefile
> index e664f1167388..e0e87239126b 100644
> --- a/tools/wmi/Makefile
> +++ b/tools/wmi/Makefile
> @@ -2,7 +2,6 @@ PREFIX ?= /usr
> SBINDIR ?= sbin
> INSTALL ?= install
> CFLAGS += -D__EXPORTED_HEADERS__ -I../../include/uapi -I../../include
> -CC = $(CROSS_COMPILE)gcc
>
> TARGET = dell-smbios-example
>
> --
> 2.11.0
>

2018-01-07 18:31:58

by Martin Kelly

[permalink] [raw]
Subject: Re: [PATCH] tools: fix cross-compile var export

On 01/07/2018 08:11 AM, Paul Gortmaker wrote:
> [[PATCH] tools: fix cross-compile var export] On 06/01/2018 (Sat 12:16) Martin Kelly wrote:
>
>> From: Martin Kelly <[email protected]>
>>
>> Currently in a number of Makefiles, we clobber the CC, LD, and/or STRIP env vars
>> when cross-compiling, which breaks any additional flags that might be set (such
>> as sysroot). This easily shows up by using, for instance, a Yocto SDK.
>>
>> Fix this by more carefully overriding the flags in the way that the perf
>> Makefile does.
>>
>> This patch does not fix cross-compile for all the tools (some have other bugs),
>> but it does appear to fix it for these:
>>
>> - cgroup
>> - freefall
>> - gpio
>> - hv
>> - iio
>> - leds
>> - spi
>> - vm
>> - wmi
>>
>> Signed-off-by: Martin Kelly <[email protected]>
>> ---
>> This patch touches multiple subsystems, and there doesn't appear to be a global
>> tools maintainer, so I sent this to linux-embedded kernel-janitors, and
>> linux-kbuild. Please let me know if there is a better place for it.
>
> I think you will have better luck if you go subsystem by subsystem, e.g.
> send gpio change to gpio maintainer, usb change to usb maintainer and so
> on. In addition, you'll want to try and understand/explain why those
> lines were added in the 1st place and how it won't break other existing
> use cases by removing them. Maybe "git blame" will help for that...
>
> P.
> --
>

I can send patches subsystem-by-subsystem, but this patch fixes a single
bug that applies to many Makefiles. It fixes it by putting the correct
logic into tools/scripts/Makefile.include, which each Makefiles
includes. If I do this subsystem-by-subsystem, we will just duplicate
these lines into every Makefile:

+$(call allow-override,CC,$(CROSS_COMPILE)gcc)
+$(call allow-override,AR,$(CROSS_COMPILE)ar)
+$(call allow-override,LD,$(CROSS_COMPILE)ld)
+$(call allow-override,CXX,$(CROSS_COMPILE)g++)
+$(call allow-override,CXX,$(CROSS_COMPILE)strip)

We could do this, but it's a lot of code duplication and means that
anyone making a new Makefile must also copy the lines or their Makefile
will have this bug. Since the bug fix generically applies everywhere, I
think it's most correct for it to go into the common Makefile.

If there is really no maintainer for the tools/scripts/Makefile.include
file, then maybe I have to send subsystem-by-subsystem, but that seems
less than ideal.

I do understand why the CC = $(CROSS_COMPILE)gcc lines exist; it is to
enable cross-compile when you set the $CROSS_COMPILE env var and to use
native gcc when that is not set. The bug is that if you already have $CC
set to your cross-compiler (which is what the Yocto SDK and other
toolchains do), then most of your command-line gets clobbered. Here's an
example from an ARM Yocto SDK I have:

$ echo $CC
arm-poky-linux-gnueabi-gcc -march=armv7-a -mfpu=neon -mfloat-abi=hard
-mcpu=cortex-a8
--sysroot=/home/martin/src/poky/build/sdk/sysroots/cortexa8hf-neon-poky-linux-gnueabi

$ echo $CROSS_COMPILE
arm-poky-linux-gnueabi-

$ echo ${CROSS_COMPILE}gcc
arm-poky-linux-gnueabi-gcc

Although arm-poky-linux-gnueabi-gcc is a cross-compiler, we've lost many
build flags, notably --sysroot, which enables us to find the right
libraries to link against. Without this change, I get this kind of error
in all the affected Makefiles:

martin@cascade:~/src/linux/tools$ make iio
[snip]
iio_event_monitor.c:18:10: fatal error: unistd.h: No such file or directory
#include <unistd.h>
^~~~~~~~~~

This occurs because unistd.h is in the sysroot, but we've dropped the
--sysroot flag:
$ find /home/martin/src/poky/build/sdk/sysroots -path
'*/usr/include/unistd.h'
/home/martin/src/poky/build/sdk/sysroots/cortexa8hf-neon-poky-linux-gnueabi/usr/include/unistd.h

With the change, we add do CC = $(CROSS_COMPILE)gcc if and only if CC is
not already set. I'm happy to add all these details to the commit
description.

>>
>> tools/cgroup/Makefile | 1 -
>> tools/gpio/Makefile | 2 --
>> tools/hv/Makefile | 1 -
>> tools/iio/Makefile | 2 --
>> tools/laptop/freefall/Makefile | 1 -
>> tools/leds/Makefile | 1 -
>> tools/perf/Makefile.perf | 6 ------
>> tools/power/acpi/Makefile.config | 3 ---
>> tools/scripts/Makefile.include | 18 ++++++++++++++++++
>> tools/spi/Makefile | 2 --
>> tools/usb/Makefile | 1 -
>> tools/vm/Makefile | 1 -
>> tools/wmi/Makefile | 1 -
>> 13 files changed, 18 insertions(+), 22 deletions(-)
>>
>> diff --git a/tools/cgroup/Makefile b/tools/cgroup/Makefile
>> index 860fa151640a..ffca068e4a76 100644
>> --- a/tools/cgroup/Makefile
>> +++ b/tools/cgroup/Makefile
>> @@ -1,7 +1,6 @@
>> # SPDX-License-Identifier: GPL-2.0
>> # Makefile for cgroup tools
>>
>> -CC = $(CROSS_COMPILE)gcc
>> CFLAGS = -Wall -Wextra
>>
>> all: cgroup_event_listener
>> diff --git a/tools/gpio/Makefile b/tools/gpio/Makefile
>> index 805a2c0cf4cd..240eda014b37 100644
>> --- a/tools/gpio/Makefile
>> +++ b/tools/gpio/Makefile
>> @@ -12,8 +12,6 @@ endif
>> # (this improves performance and avoids hard-to-debug behaviour);
>> MAKEFLAGS += -r
>>
>> -CC = $(CROSS_COMPILE)gcc
>> -LD = $(CROSS_COMPILE)ld
>> CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include
>>
>> ALL_TARGETS := lsgpio gpio-hammer gpio-event-mon
>> diff --git a/tools/hv/Makefile b/tools/hv/Makefile
>> index 31503819454d..68c2d7b059b3 100644
>> --- a/tools/hv/Makefile
>> +++ b/tools/hv/Makefile
>> @@ -1,7 +1,6 @@
>> # SPDX-License-Identifier: GPL-2.0
>> # Makefile for Hyper-V tools
>>
>> -CC = $(CROSS_COMPILE)gcc
>> WARNINGS = -Wall -Wextra
>> CFLAGS = $(WARNINGS) -g $(shell getconf LFS_CFLAGS)
>>
>> diff --git a/tools/iio/Makefile b/tools/iio/Makefile
>> index a08e7a47d6a3..332ed2f6c2c2 100644
>> --- a/tools/iio/Makefile
>> +++ b/tools/iio/Makefile
>> @@ -12,8 +12,6 @@ endif
>> # (this improves performance and avoids hard-to-debug behaviour);
>> MAKEFLAGS += -r
>>
>> -CC = $(CROSS_COMPILE)gcc
>> -LD = $(CROSS_COMPILE)ld
>> CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include
>>
>> ALL_TARGETS := iio_event_monitor lsiio iio_generic_buffer
>> diff --git a/tools/laptop/freefall/Makefile b/tools/laptop/freefall/Makefile
>> index 5f758c489a20..b572d94255f6 100644
>> --- a/tools/laptop/freefall/Makefile
>> +++ b/tools/laptop/freefall/Makefile
>> @@ -2,7 +2,6 @@
>> PREFIX ?= /usr
>> SBINDIR ?= sbin
>> INSTALL ?= install
>> -CC = $(CROSS_COMPILE)gcc
>>
>> TARGET = freefall
>>
>> diff --git a/tools/leds/Makefile b/tools/leds/Makefile
>> index c379af003807..7b6bed13daaa 100644
>> --- a/tools/leds/Makefile
>> +++ b/tools/leds/Makefile
>> @@ -1,7 +1,6 @@
>> # SPDX-License-Identifier: GPL-2.0
>> # Makefile for LEDs tools
>>
>> -CC = $(CROSS_COMPILE)gcc
>> CFLAGS = -Wall -Wextra -g -I../../include/uapi
>>
>> all: uledmon led_hw_brightness_mon
>> diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
>> index 68cf1360a3f3..3035ce5f6b36 100644
>> --- a/tools/perf/Makefile.perf
>> +++ b/tools/perf/Makefile.perf
>> @@ -144,12 +144,6 @@ define allow-override
>> $(eval $(1) = $(2)))
>> endef
>>
>> -# Allow setting CC and AR and LD, or setting CROSS_COMPILE as a prefix.
>> -$(call allow-override,CC,$(CROSS_COMPILE)gcc)
>> -$(call allow-override,AR,$(CROSS_COMPILE)ar)
>> -$(call allow-override,LD,$(CROSS_COMPILE)ld)
>> -$(call allow-override,CXX,$(CROSS_COMPILE)g++)
>> -
>> LD += $(EXTRA_LDFLAGS)
>>
>> HOSTCC ?= gcc
>> diff --git a/tools/power/acpi/Makefile.config b/tools/power/acpi/Makefile.config
>> index a1883bbb0144..2cccbba64418 100644
>> --- a/tools/power/acpi/Makefile.config
>> +++ b/tools/power/acpi/Makefile.config
>> @@ -56,9 +56,6 @@ INSTALL_SCRIPT = ${INSTALL_PROGRAM}
>> # to compile vs uClibc, that can be done here as well.
>> CROSS = #/usr/i386-linux-uclibc/usr/bin/i386-uclibc-
>> CROSS_COMPILE ?= $(CROSS)
>> -CC = $(CROSS_COMPILE)gcc
>> -LD = $(CROSS_COMPILE)gcc
>> -STRIP = $(CROSS_COMPILE)strip
>> HOSTCC = gcc
>>
>> # check if compiler option is supported
>> diff --git a/tools/scripts/Makefile.include b/tools/scripts/Makefile.include
>> index 3fab179b1aba..09b2d0f07f66 100644
>> --- a/tools/scripts/Makefile.include
>> +++ b/tools/scripts/Makefile.include
>> @@ -42,6 +42,24 @@ EXTRA_WARNINGS += -Wformat
>>
>> CC_NO_CLANG := $(shell $(CC) -dM -E -x c /dev/null | grep -Fq "__clang__"; echo $$?)
>>
>> +# Makefiles suck: This macro sets a default value of $(2) for the
>> +# variable named by $(1), unless the variable has been set by
>> +# environment or command line. This is necessary for CC and AR
>> +# because make sets default values, so the simpler ?= approach
>> +# won't work as expected.
>> +define allow-override
>> + $(if $(or $(findstring environment,$(origin $(1))),\
>> + $(findstring command line,$(origin $(1)))),,\
>> + $(eval $(1) = $(2)))
>> +endef
>> +
>> +# Allow setting various cross-compile vars or setting CROSS_COMPILE as a prefix.
>> +$(call allow-override,CC,$(CROSS_COMPILE)gcc)
>> +$(call allow-override,AR,$(CROSS_COMPILE)ar)
>> +$(call allow-override,LD,$(CROSS_COMPILE)ld)
>> +$(call allow-override,CXX,$(CROSS_COMPILE)g++)
>> +$(call allow-override,CXX,$(CROSS_COMPILE)strip)
>> +
>> ifeq ($(CC_NO_CLANG), 1)
>> EXTRA_WARNINGS += -Wstrict-aliasing=3
>> endif
>> diff --git a/tools/spi/Makefile b/tools/spi/Makefile
>> index 90615e10c79a..815d15589177 100644
>> --- a/tools/spi/Makefile
>> +++ b/tools/spi/Makefile
>> @@ -11,8 +11,6 @@ endif
>> # (this improves performance and avoids hard-to-debug behaviour);
>> MAKEFLAGS += -r
>>
>> -CC = $(CROSS_COMPILE)gcc
>> -LD = $(CROSS_COMPILE)ld
>> CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include
>>
>> ALL_TARGETS := spidev_test spidev_fdx
>> diff --git a/tools/usb/Makefile b/tools/usb/Makefile
>> index 4e6506078494..01d758d73b6d 100644
>> --- a/tools/usb/Makefile
>> +++ b/tools/usb/Makefile
>> @@ -1,7 +1,6 @@
>> # SPDX-License-Identifier: GPL-2.0
>> # Makefile for USB tools
>>
>> -CC = $(CROSS_COMPILE)gcc
>> PTHREAD_LIBS = -lpthread
>> WARNINGS = -Wall -Wextra
>> CFLAGS = $(WARNINGS) -g -I../include
>> diff --git a/tools/vm/Makefile b/tools/vm/Makefile
>> index be320b905ea7..20f6cf04377f 100644
>> --- a/tools/vm/Makefile
>> +++ b/tools/vm/Makefile
>> @@ -6,7 +6,6 @@ TARGETS=page-types slabinfo page_owner_sort
>> LIB_DIR = ../lib/api
>> LIBS = $(LIB_DIR)/libapi.a
>>
>> -CC = $(CROSS_COMPILE)gcc
>> CFLAGS = -Wall -Wextra -I../lib/
>> LDFLAGS = $(LIBS)
>>
>> diff --git a/tools/wmi/Makefile b/tools/wmi/Makefile
>> index e664f1167388..e0e87239126b 100644
>> --- a/tools/wmi/Makefile
>> +++ b/tools/wmi/Makefile
>> @@ -2,7 +2,6 @@ PREFIX ?= /usr
>> SBINDIR ?= sbin
>> INSTALL ?= install
>> CFLAGS += -D__EXPORTED_HEADERS__ -I../../include/uapi -I../../include
>> -CC = $(CROSS_COMPILE)gcc
>>
>> TARGET = dell-smbios-example
>>
>> --
>> 2.11.0
>>

2018-01-07 18:51:26

by Martin Kelly

[permalink] [raw]
Subject: Re: [PATCH] tools: fix cross-compile var export

On 01/07/2018 10:31 AM, Martin Kelly wrote:
> On 01/07/2018 08:11 AM, Paul Gortmaker wrote:
>> [[PATCH] tools: fix cross-compile var export] On 06/01/2018 (Sat
>> 12:16) Martin Kelly wrote:
>>
>>> From: Martin Kelly <[email protected]>
>>>
>>> Currently in a number of Makefiles, we clobber the CC, LD, and/or
>>> STRIP env vars
>>> when cross-compiling, which breaks any additional flags that might be
>>> set (such
>>> as sysroot). This easily shows up by using, for instance, a Yocto SDK.
>>>
>>> Fix this by more carefully overriding the flags in the way that the perf
>>> Makefile does.
>>>
>>> This patch does not fix cross-compile for all the tools (some have
>>> other bugs),
>>> but it does appear to fix it for these:
>>>
>>> - cgroup
>>> - freefall
>>> - gpio
>>> - hv
>>> - iio
>>> - leds
>>> - spi
>>> - vm
>>> - wmi
>>>
>>> Signed-off-by: Martin Kelly <[email protected]>
>>> ---
>>> This patch touches multiple subsystems, and there doesn't appear to
>>> be a global
>>> tools maintainer, so I sent this to linux-embedded kernel-janitors, and
>>> linux-kbuild. Please let me know if there is a better place for it.
>>
>> I think you will have better luck if you go subsystem by subsystem, e.g.
>> send gpio change to gpio maintainer, usb change to usb maintainer and so
>> on.  In addition, you'll want to try and understand/explain why those
>> lines were added in the 1st place and how it won't break other existing
>> use cases by removing them.  Maybe "git blame" will help for that...
>>
>> P.
>> --
>>
>
> I can send patches subsystem-by-subsystem, but this patch fixes a single
> bug that applies to many Makefiles. It fixes it by putting the correct
> logic into tools/scripts/Makefile.include, which each Makefiles
> includes. If I do this subsystem-by-subsystem, we will just duplicate
> these lines into every Makefile:
>
> +$(call allow-override,CC,$(CROSS_COMPILE)gcc)
> +$(call allow-override,AR,$(CROSS_COMPILE)ar)
> +$(call allow-override,LD,$(CROSS_COMPILE)ld)
> +$(call allow-override,CXX,$(CROSS_COMPILE)g++)
> +$(call allow-override,CXX,$(CROSS_COMPILE)strip)
>
> We could do this, but it's a lot of code duplication and means that
> anyone making a new Makefile must also copy the lines or their Makefile
> will have this bug. Since the bug fix generically applies everywhere, I
> think it's most correct for it to go into the common Makefile.
>
> If there is really no maintainer for the tools/scripts/Makefile.include
> file, then maybe I have to send subsystem-by-subsystem, but that seems
> less than ideal.
>
> I do understand why the CC = $(CROSS_COMPILE)gcc lines exist; it is to
> enable cross-compile when you set the $CROSS_COMPILE env var and to use
> native gcc when that is not set. The bug is that if you already have $CC
> set to your cross-compiler (which is what the Yocto SDK and other
> toolchains do), then most of your command-line gets clobbered. Here's an
> example from an ARM Yocto SDK I have:
>
> $ echo $CC
> arm-poky-linux-gnueabi-gcc -march=armv7-a -mfpu=neon -mfloat-abi=hard
> -mcpu=cortex-a8
> --sysroot=/home/martin/src/poky/build/sdk/sysroots/cortexa8hf-neon-poky-linux-gnueabi
>
>
> $ echo $CROSS_COMPILE
> arm-poky-linux-gnueabi-
>
> $ echo ${CROSS_COMPILE}gcc
> arm-poky-linux-gnueabi-gcc
>
> Although arm-poky-linux-gnueabi-gcc is a cross-compiler, we've lost many
> build flags, notably --sysroot, which enables us to find the right
> libraries to link against. Without this change, I get this kind of error
> in all the affected Makefiles:
>
> martin@cascade:~/src/linux/tools$ make iio
> [snip]
> iio_event_monitor.c:18:10: fatal error: unistd.h: No such file or directory
>  #include <unistd.h>
>           ^~~~~~~~~~
>
> This occurs because unistd.h is in the sysroot, but we've dropped the
> --sysroot flag:
> $ find /home/martin/src/poky/build/sdk/sysroots -path
> '*/usr/include/unistd.h'
> /home/martin/src/poky/build/sdk/sysroots/cortexa8hf-neon-poky-linux-gnueabi/usr/include/unistd.h
>
>
> With the change, we add do CC = $(CROSS_COMPILE)gcc if and only if CC is
> not already set. I'm happy to add all these details to the commit
> description.
>

Urg, I accidentally sent to kernel-kbuild instead of linux-kbuild,
changed now. It appears that past changes to
tools/scripts/Makefile.include have been handled by linux-kbuild and
often Masahiro Yamada.

Perhaps the best sequence here is to send a patch to kbuild adding the
call-override function and calls to it to the main common Makefile. Then
I can send individual subsystem patches dropping the individual CC =
lines and similar. It will be 13 patches instead of 1 but will
eventually result in the same thing.

Paul, any thoughts?

>>>
>>>   tools/cgroup/Makefile            |  1 -
>>>   tools/gpio/Makefile              |  2 --
>>>   tools/hv/Makefile                |  1 -
>>>   tools/iio/Makefile               |  2 --
>>>   tools/laptop/freefall/Makefile   |  1 -
>>>   tools/leds/Makefile              |  1 -
>>>   tools/perf/Makefile.perf         |  6 ------
>>>   tools/power/acpi/Makefile.config |  3 ---
>>>   tools/scripts/Makefile.include   | 18 ++++++++++++++++++
>>>   tools/spi/Makefile               |  2 --
>>>   tools/usb/Makefile               |  1 -
>>>   tools/vm/Makefile                |  1 -
>>>   tools/wmi/Makefile               |  1 -
>>>   13 files changed, 18 insertions(+), 22 deletions(-)
>>>
>>> diff --git a/tools/cgroup/Makefile b/tools/cgroup/Makefile
>>> index 860fa151640a..ffca068e4a76 100644
>>> --- a/tools/cgroup/Makefile
>>> +++ b/tools/cgroup/Makefile
>>> @@ -1,7 +1,6 @@
>>>   # SPDX-License-Identifier: GPL-2.0
>>>   # Makefile for cgroup tools
>>> -CC = $(CROSS_COMPILE)gcc
>>>   CFLAGS = -Wall -Wextra
>>>   all: cgroup_event_listener
>>> diff --git a/tools/gpio/Makefile b/tools/gpio/Makefile
>>> index 805a2c0cf4cd..240eda014b37 100644
>>> --- a/tools/gpio/Makefile
>>> +++ b/tools/gpio/Makefile
>>> @@ -12,8 +12,6 @@ endif
>>>   # (this improves performance and avoids hard-to-debug behaviour);
>>>   MAKEFLAGS += -r
>>> -CC = $(CROSS_COMPILE)gcc
>>> -LD = $(CROSS_COMPILE)ld
>>>   CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include
>>>   ALL_TARGETS := lsgpio gpio-hammer gpio-event-mon
>>> diff --git a/tools/hv/Makefile b/tools/hv/Makefile
>>> index 31503819454d..68c2d7b059b3 100644
>>> --- a/tools/hv/Makefile
>>> +++ b/tools/hv/Makefile
>>> @@ -1,7 +1,6 @@
>>>   # SPDX-License-Identifier: GPL-2.0
>>>   # Makefile for Hyper-V tools
>>> -CC = $(CROSS_COMPILE)gcc
>>>   WARNINGS = -Wall -Wextra
>>>   CFLAGS = $(WARNINGS) -g $(shell getconf LFS_CFLAGS)
>>> diff --git a/tools/iio/Makefile b/tools/iio/Makefile
>>> index a08e7a47d6a3..332ed2f6c2c2 100644
>>> --- a/tools/iio/Makefile
>>> +++ b/tools/iio/Makefile
>>> @@ -12,8 +12,6 @@ endif
>>>   # (this improves performance and avoids hard-to-debug behaviour);
>>>   MAKEFLAGS += -r
>>> -CC = $(CROSS_COMPILE)gcc
>>> -LD = $(CROSS_COMPILE)ld
>>>   CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include
>>>   ALL_TARGETS := iio_event_monitor lsiio iio_generic_buffer
>>> diff --git a/tools/laptop/freefall/Makefile
>>> b/tools/laptop/freefall/Makefile
>>> index 5f758c489a20..b572d94255f6 100644
>>> --- a/tools/laptop/freefall/Makefile
>>> +++ b/tools/laptop/freefall/Makefile
>>> @@ -2,7 +2,6 @@
>>>   PREFIX ?= /usr
>>>   SBINDIR ?= sbin
>>>   INSTALL ?= install
>>> -CC = $(CROSS_COMPILE)gcc
>>>   TARGET = freefall
>>> diff --git a/tools/leds/Makefile b/tools/leds/Makefile
>>> index c379af003807..7b6bed13daaa 100644
>>> --- a/tools/leds/Makefile
>>> +++ b/tools/leds/Makefile
>>> @@ -1,7 +1,6 @@
>>>   # SPDX-License-Identifier: GPL-2.0
>>>   # Makefile for LEDs tools
>>> -CC = $(CROSS_COMPILE)gcc
>>>   CFLAGS = -Wall -Wextra -g -I../../include/uapi
>>>   all: uledmon led_hw_brightness_mon
>>> diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
>>> index 68cf1360a3f3..3035ce5f6b36 100644
>>> --- a/tools/perf/Makefile.perf
>>> +++ b/tools/perf/Makefile.perf
>>> @@ -144,12 +144,6 @@ define allow-override
>>>       $(eval $(1) = $(2)))
>>>   endef
>>> -# Allow setting CC and AR and LD, or setting CROSS_COMPILE as a prefix.
>>> -$(call allow-override,CC,$(CROSS_COMPILE)gcc)
>>> -$(call allow-override,AR,$(CROSS_COMPILE)ar)
>>> -$(call allow-override,LD,$(CROSS_COMPILE)ld)
>>> -$(call allow-override,CXX,$(CROSS_COMPILE)g++)
>>> -
>>>   LD += $(EXTRA_LDFLAGS)
>>>   HOSTCC  ?= gcc
>>> diff --git a/tools/power/acpi/Makefile.config
>>> b/tools/power/acpi/Makefile.config
>>> index a1883bbb0144..2cccbba64418 100644
>>> --- a/tools/power/acpi/Makefile.config
>>> +++ b/tools/power/acpi/Makefile.config
>>> @@ -56,9 +56,6 @@ INSTALL_SCRIPT = ${INSTALL_PROGRAM}
>>>   # to compile vs uClibc, that can be done here as well.
>>>   CROSS = #/usr/i386-linux-uclibc/usr/bin/i386-uclibc-
>>>   CROSS_COMPILE ?= $(CROSS)
>>> -CC = $(CROSS_COMPILE)gcc
>>> -LD = $(CROSS_COMPILE)gcc
>>> -STRIP = $(CROSS_COMPILE)strip
>>>   HOSTCC = gcc
>>>   # check if compiler option is supported
>>> diff --git a/tools/scripts/Makefile.include
>>> b/tools/scripts/Makefile.include
>>> index 3fab179b1aba..09b2d0f07f66 100644
>>> --- a/tools/scripts/Makefile.include
>>> +++ b/tools/scripts/Makefile.include
>>> @@ -42,6 +42,24 @@ EXTRA_WARNINGS += -Wformat
>>>   CC_NO_CLANG := $(shell $(CC) -dM -E -x c /dev/null | grep -Fq
>>> "__clang__"; echo $$?)
>>> +# Makefiles suck: This macro sets a default value of $(2) for the
>>> +# variable named by $(1), unless the variable has been set by
>>> +# environment or command line. This is necessary for CC and AR
>>> +# because make sets default values, so the simpler ?= approach
>>> +# won't work as expected.
>>> +define allow-override
>>> +  $(if $(or $(findstring environment,$(origin $(1))),\
>>> +            $(findstring command line,$(origin $(1)))),,\
>>> +    $(eval $(1) = $(2)))
>>> +endef
>>> +
>>> +# Allow setting various cross-compile vars or setting CROSS_COMPILE
>>> as a prefix.
>>> +$(call allow-override,CC,$(CROSS_COMPILE)gcc)
>>> +$(call allow-override,AR,$(CROSS_COMPILE)ar)
>>> +$(call allow-override,LD,$(CROSS_COMPILE)ld)
>>> +$(call allow-override,CXX,$(CROSS_COMPILE)g++)
>>> +$(call allow-override,CXX,$(CROSS_COMPILE)strip)
>>> +
>>>   ifeq ($(CC_NO_CLANG), 1)
>>>   EXTRA_WARNINGS += -Wstrict-aliasing=3
>>>   endif
>>> diff --git a/tools/spi/Makefile b/tools/spi/Makefile
>>> index 90615e10c79a..815d15589177 100644
>>> --- a/tools/spi/Makefile
>>> +++ b/tools/spi/Makefile
>>> @@ -11,8 +11,6 @@ endif
>>>   # (this improves performance and avoids hard-to-debug behaviour);
>>>   MAKEFLAGS += -r
>>> -CC = $(CROSS_COMPILE)gcc
>>> -LD = $(CROSS_COMPILE)ld
>>>   CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include
>>>   ALL_TARGETS := spidev_test spidev_fdx
>>> diff --git a/tools/usb/Makefile b/tools/usb/Makefile
>>> index 4e6506078494..01d758d73b6d 100644
>>> --- a/tools/usb/Makefile
>>> +++ b/tools/usb/Makefile
>>> @@ -1,7 +1,6 @@
>>>   # SPDX-License-Identifier: GPL-2.0
>>>   # Makefile for USB tools
>>> -CC = $(CROSS_COMPILE)gcc
>>>   PTHREAD_LIBS = -lpthread
>>>   WARNINGS = -Wall -Wextra
>>>   CFLAGS = $(WARNINGS) -g -I../include
>>> diff --git a/tools/vm/Makefile b/tools/vm/Makefile
>>> index be320b905ea7..20f6cf04377f 100644
>>> --- a/tools/vm/Makefile
>>> +++ b/tools/vm/Makefile
>>> @@ -6,7 +6,6 @@ TARGETS=page-types slabinfo page_owner_sort
>>>   LIB_DIR = ../lib/api
>>>   LIBS = $(LIB_DIR)/libapi.a
>>> -CC = $(CROSS_COMPILE)gcc
>>>   CFLAGS = -Wall -Wextra -I../lib/
>>>   LDFLAGS = $(LIBS)
>>> diff --git a/tools/wmi/Makefile b/tools/wmi/Makefile
>>> index e664f1167388..e0e87239126b 100644
>>> --- a/tools/wmi/Makefile
>>> +++ b/tools/wmi/Makefile
>>> @@ -2,7 +2,6 @@ PREFIX ?= /usr
>>>   SBINDIR ?= sbin
>>>   INSTALL ?= install
>>>   CFLAGS += -D__EXPORTED_HEADERS__ -I../../include/uapi -I../../include
>>> -CC = $(CROSS_COMPILE)gcc
>>>   TARGET = dell-smbios-example
>>> --
>>> 2.11.0
>>>

2018-01-07 19:05:37

by Paul Gortmaker

[permalink] [raw]
Subject: Re: [PATCH] tools: fix cross-compile var export

[Re: [PATCH] tools: fix cross-compile var export] On 07/01/2018 (Sun 10:31) Martin Kelly wrote:

[...]

> With the change, we add do CC = $(CROSS_COMPILE)gcc if and only if CC is not
> already set. I'm happy to add all these details to the commit description.

That is probably a step in the right direction. I contribute to yocto
on a regular basis and hence am sympathetic to these frustrating SDK
type issues. But after a quick scan of this patch it wasn't obvious to
me that existing behaviour was preserved, or that it would be a pain to
separate it into chunks. (key word here being "quick")

So I'd recommend updating the commit log, and adding a Cc: line for the
maintainers of each subsystem below, and then if nobody complains you
might get akpm to pick it up as he does for other patches w/o a clear
maintainer or subsystem.

P.
--

>
> >>
> >> tools/cgroup/Makefile | 1 -
> >> tools/gpio/Makefile | 2 --
> >> tools/hv/Makefile | 1 -
> >> tools/iio/Makefile | 2 --
> >> tools/laptop/freefall/Makefile | 1 -
> >> tools/leds/Makefile | 1 -
> >> tools/perf/Makefile.perf | 6 ------
> >> tools/power/acpi/Makefile.config | 3 ---
> >> tools/scripts/Makefile.include | 18 ++++++++++++++++++
> >> tools/spi/Makefile | 2 --
> >> tools/usb/Makefile | 1 -
> >> tools/vm/Makefile | 1 -
> >> tools/wmi/Makefile | 1 -
> >> 13 files changed, 18 insertions(+), 22 deletions(-)
> >>

2018-01-07 21:41:59

by Martin Kelly

[permalink] [raw]
Subject: [PATCH v2] tools: fix cross-compile var clobbering

From: Martin Kelly <[email protected]>

Currently a number of Makefiles break when used with toolchains that pass
extra flags in CC and other cross-compile related variables (such as
--sysroot). Thus we get this error when we use a toolchain that puts
--sysroot in the CC var:

~/src/linux/tools$ make iio
[snip]
iio_event_monitor.c:18:10: fatal error: unistd.h: No such file or directory
#include <unistd.h>
^~~~~~~~~~

This occurs because we clobber several env vars related to cross-compiling
with lines like this:

CC = $(CROSS_COMPILE)gcc

Although this will point to a valid cross-compiler, we lose any extra flags
that might exist in the CC variable, which can break toolchains that rely
on them (for example, those that use --sysroot). This easily shows up using
a Yocto SDK:

$ . [snip]/sdk/environment-setup-cortexa8hf-neon-poky-linux-gnueabi

$ echo $CC
arm-poky-linux-gnueabi-gcc -march=armv7-a -mfpu=neon -mfloat-abi=hard
-mcpu=cortex-a8
--sysroot=[snip]/sdk/sysroots/cortexa8hf-neon-poky-linux-gnueabi

$ echo $CROSS_COMPILE
arm-poky-linux-gnueabi-

$ echo ${CROSS_COMPILE}gcc
krm-poky-linux-gnueabi-gcc

Although arm-poky-linux-gnueabi-gcc is a cross-compiler, we've lost the
--sysroot and other flags that enable us to find the right libraries to
link against, so we can't find unistd.h and other libraries and headers.
Normally with the --sysroot flag we would find unistd.h in the sdk
directory in the sysroot:

$ find [snip]/sdk/sysroots -path '*/usr/include/unistd.h'
[snip]/sdk/sysroots/cortexa8hf-neon-poky-linux-gnueabi/usr/include/unistd.h

The perf Makefile adds CC = $(CROSS_COMPILE)gcc if and only if CC is not
already set, and it compiles correctly with the above toolchain.

So, generalize the logic that perf uses in the common Makefile and remove
the manual CC = $(CROSS_COMPILE)gcc lines from each Makefile.

Note that this patch does not fix cross-compile for all the tools (some
have other bugs), but it does fix it for all except usb and acpi, which
still have other unrelated issues.

I tested both with and without the patch on native and cross-build and
there appear to be no regressions.

Cc: Tejun Heo <[email protected]>
Cc: Li Zefan <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Linus Walleij <[email protected]>
Cc: "K. Y. Srinivasan" <[email protected]>
Cc: Haiyang Zhang <[email protected]>
Cc: Stephen Hemminger <[email protected]>
Cc: Jonathan Cameron <[email protected]>
Cc: Pali Rohár <[email protected]>
Cc: Richard Purdie <[email protected]>
Cc: Jacek Anaszewski <[email protected]>
Cc: Pavel Machek <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Robert Moore <[email protected]>
Cc: Lv Zheng <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Mark Brown <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Valentina Manea <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Mario Limonciello <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: [email protected]
Signed-off-by: Martin Kelly <[email protected]>
---
Since there is no globals tools maintainer, I'm sending this to linux-kbuild as
the closest match and CC-ing all affected subsystem maintainers. If no one has
objections, I'm hoping Andrew Morton can pull in the patch.

v2:
- Expand commit description to fill in more detail and CC all relevant
maintainers.
- Fix small typo related to the STRIP variable.

tools/cgroup/Makefile | 1 -
tools/gpio/Makefile | 2 --
tools/hv/Makefile | 1 -
tools/iio/Makefile | 2 --
tools/laptop/freefall/Makefile | 1 -
tools/leds/Makefile | 1 -
tools/perf/Makefile.perf | 6 ------
tools/power/acpi/Makefile.config | 3 ---
tools/scripts/Makefile.include | 18 ++++++++++++++++++
tools/spi/Makefile | 2 --
tools/usb/Makefile | 1 -
tools/vm/Makefile | 1 -
tools/wmi/Makefile | 1 -
13 files changed, 18 insertions(+), 22 deletions(-)

diff --git a/tools/cgroup/Makefile b/tools/cgroup/Makefile
index 860fa151640a..ffca068e4a76 100644
--- a/tools/cgroup/Makefile
+++ b/tools/cgroup/Makefile
@@ -1,7 +1,6 @@
# SPDX-License-Identifier: GPL-2.0
# Makefile for cgroup tools

-CC = $(CROSS_COMPILE)gcc
CFLAGS = -Wall -Wextra

all: cgroup_event_listener
diff --git a/tools/gpio/Makefile b/tools/gpio/Makefile
index 805a2c0cf4cd..240eda014b37 100644
--- a/tools/gpio/Makefile
+++ b/tools/gpio/Makefile
@@ -12,8 +12,6 @@ endif
# (this improves performance and avoids hard-to-debug behaviour);
MAKEFLAGS += -r

-CC = $(CROSS_COMPILE)gcc
-LD = $(CROSS_COMPILE)ld
CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include

ALL_TARGETS := lsgpio gpio-hammer gpio-event-mon
diff --git a/tools/hv/Makefile b/tools/hv/Makefile
index 31503819454d..68c2d7b059b3 100644
--- a/tools/hv/Makefile
+++ b/tools/hv/Makefile
@@ -1,7 +1,6 @@
# SPDX-License-Identifier: GPL-2.0
# Makefile for Hyper-V tools

-CC = $(CROSS_COMPILE)gcc
WARNINGS = -Wall -Wextra
CFLAGS = $(WARNINGS) -g $(shell getconf LFS_CFLAGS)

diff --git a/tools/iio/Makefile b/tools/iio/Makefile
index a08e7a47d6a3..332ed2f6c2c2 100644
--- a/tools/iio/Makefile
+++ b/tools/iio/Makefile
@@ -12,8 +12,6 @@ endif
# (this improves performance and avoids hard-to-debug behaviour);
MAKEFLAGS += -r

-CC = $(CROSS_COMPILE)gcc
-LD = $(CROSS_COMPILE)ld
CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include

ALL_TARGETS := iio_event_monitor lsiio iio_generic_buffer
diff --git a/tools/laptop/freefall/Makefile b/tools/laptop/freefall/Makefile
index 5f758c489a20..b572d94255f6 100644
--- a/tools/laptop/freefall/Makefile
+++ b/tools/laptop/freefall/Makefile
@@ -2,7 +2,6 @@
PREFIX ?= /usr
SBINDIR ?= sbin
INSTALL ?= install
-CC = $(CROSS_COMPILE)gcc

TARGET = freefall

diff --git a/tools/leds/Makefile b/tools/leds/Makefile
index c379af003807..7b6bed13daaa 100644
--- a/tools/leds/Makefile
+++ b/tools/leds/Makefile
@@ -1,7 +1,6 @@
# SPDX-License-Identifier: GPL-2.0
# Makefile for LEDs tools

-CC = $(CROSS_COMPILE)gcc
CFLAGS = -Wall -Wextra -g -I../../include/uapi

all: uledmon led_hw_brightness_mon
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 68cf1360a3f3..3035ce5f6b36 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -144,12 +144,6 @@ define allow-override
$(eval $(1) = $(2)))
endef

-# Allow setting CC and AR and LD, or setting CROSS_COMPILE as a prefix.
-$(call allow-override,CC,$(CROSS_COMPILE)gcc)
-$(call allow-override,AR,$(CROSS_COMPILE)ar)
-$(call allow-override,LD,$(CROSS_COMPILE)ld)
-$(call allow-override,CXX,$(CROSS_COMPILE)g++)
-
LD += $(EXTRA_LDFLAGS)

HOSTCC ?= gcc
diff --git a/tools/power/acpi/Makefile.config b/tools/power/acpi/Makefile.config
index a1883bbb0144..2cccbba64418 100644
--- a/tools/power/acpi/Makefile.config
+++ b/tools/power/acpi/Makefile.config
@@ -56,9 +56,6 @@ INSTALL_SCRIPT = ${INSTALL_PROGRAM}
# to compile vs uClibc, that can be done here as well.
CROSS = #/usr/i386-linux-uclibc/usr/bin/i386-uclibc-
CROSS_COMPILE ?= $(CROSS)
-CC = $(CROSS_COMPILE)gcc
-LD = $(CROSS_COMPILE)gcc
-STRIP = $(CROSS_COMPILE)strip
HOSTCC = gcc

# check if compiler option is supported
diff --git a/tools/scripts/Makefile.include b/tools/scripts/Makefile.include
index 3fab179b1aba..853e5e949c61 100644
--- a/tools/scripts/Makefile.include
+++ b/tools/scripts/Makefile.include
@@ -42,6 +42,24 @@ EXTRA_WARNINGS += -Wformat

CC_NO_CLANG := $(shell $(CC) -dM -E -x c /dev/null | grep -Fq "__clang__"; echo $$?)

+# Makefiles suck: This macro sets a default value of $(2) for the
+# variable named by $(1), unless the variable has been set by
+# environment or command line. This is necessary for CC and AR
+# because make sets default values, so the simpler ?= approach
+# won't work as expected.
+define allow-override
+ $(if $(or $(findstring environment,$(origin $(1))),\
+ $(findstring command line,$(origin $(1)))),,\
+ $(eval $(1) = $(2)))
+endef
+
+# Allow setting various cross-compile vars or setting CROSS_COMPILE as a prefix.
+$(call allow-override,CC,$(CROSS_COMPILE)gcc)
+$(call allow-override,AR,$(CROSS_COMPILE)ar)
+$(call allow-override,LD,$(CROSS_COMPILE)ld)
+$(call allow-override,CXX,$(CROSS_COMPILE)g++)
+$(call allow-override,STRIP,$(CROSS_COMPILE)strip)
+
ifeq ($(CC_NO_CLANG), 1)
EXTRA_WARNINGS += -Wstrict-aliasing=3
endif
diff --git a/tools/spi/Makefile b/tools/spi/Makefile
index 90615e10c79a..815d15589177 100644
--- a/tools/spi/Makefile
+++ b/tools/spi/Makefile
@@ -11,8 +11,6 @@ endif
# (this improves performance and avoids hard-to-debug behaviour);
MAKEFLAGS += -r

-CC = $(CROSS_COMPILE)gcc
-LD = $(CROSS_COMPILE)ld
CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include

ALL_TARGETS := spidev_test spidev_fdx
diff --git a/tools/usb/Makefile b/tools/usb/Makefile
index 4e6506078494..01d758d73b6d 100644
--- a/tools/usb/Makefile
+++ b/tools/usb/Makefile
@@ -1,7 +1,6 @@
# SPDX-License-Identifier: GPL-2.0
# Makefile for USB tools

-CC = $(CROSS_COMPILE)gcc
PTHREAD_LIBS = -lpthread
WARNINGS = -Wall -Wextra
CFLAGS = $(WARNINGS) -g -I../include
diff --git a/tools/vm/Makefile b/tools/vm/Makefile
index be320b905ea7..20f6cf04377f 100644
--- a/tools/vm/Makefile
+++ b/tools/vm/Makefile
@@ -6,7 +6,6 @@ TARGETS=page-types slabinfo page_owner_sort
LIB_DIR = ../lib/api
LIBS = $(LIB_DIR)/libapi.a

-CC = $(CROSS_COMPILE)gcc
CFLAGS = -Wall -Wextra -I../lib/
LDFLAGS = $(LIBS)

diff --git a/tools/wmi/Makefile b/tools/wmi/Makefile
index e664f1167388..e0e87239126b 100644
--- a/tools/wmi/Makefile
+++ b/tools/wmi/Makefile
@@ -2,7 +2,6 @@ PREFIX ?= /usr
SBINDIR ?= sbin
INSTALL ?= install
CFLAGS += -D__EXPORTED_HEADERS__ -I../../include/uapi -I../../include
-CC = $(CROSS_COMPILE)gcc

TARGET = dell-smbios-example

--
2.11.0

2018-01-07 21:43:37

by Martin Kelly

[permalink] [raw]
Subject: Re: [PATCH] tools: fix cross-compile var export

On 01/07/2018 11:04 AM, Paul Gortmaker wrote:
> [Re: [PATCH] tools: fix cross-compile var export] On 07/01/2018 (Sun 10:31) Martin Kelly wrote:
>
> [...]
>
>> With the change, we add do CC = $(CROSS_COMPILE)gcc if and only if CC is not
>> already set. I'm happy to add all these details to the commit description.
>
> That is probably a step in the right direction. I contribute to yocto
> on a regular basis and hence am sympathetic to these frustrating SDK
> type issues. But after a quick scan of this patch it wasn't obvious to
> me that existing behaviour was preserved, or that it would be a pain to
> separate it into chunks. (key word here being "quick")
>
> So I'd recommend updating the commit log, and adding a Cc: line for the
> maintainers of each subsystem below, and then if nobody complains you
> might get akpm to pick it up as he does for other patches w/o a clear
> maintainer or subsystem.
>
> P

Thanks, I have done so. I also contribute to Yocto and indeed, SDK
issues are all-to-common.

2018-01-08 11:22:48

by Mark Brown

[permalink] [raw]
Subject: Re: [PATCH v2] tools: fix cross-compile var clobbering

On Sun, Jan 07, 2018 at 01:40:28PM -0800, Martin Kelly wrote:
> From: Martin Kelly <[email protected]>
>
> Currently a number of Makefiles break when used with toolchains that pass
> extra flags in CC and other cross-compile related variables (such as
> --sysroot). Thus we get this error when we use a toolchain that puts
> --sysroot in the CC var:

Acked-by: Mark Brown <[email protected]>


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2018-01-08 11:46:43

by Dan Carpenter

[permalink] [raw]
Subject: Re: [PATCH] tools: fix cross-compile var export

On Sun, Jan 07, 2018 at 10:51:21AM -0800, Martin Kelly wrote:
> Urg, I accidentally sent to kernel-kbuild instead of linux-kbuild, changed
> now. It appears that past changes to tools/scripts/Makefile.include have
> been handled by linux-kbuild and often Masahiro Yamada.
>
> Perhaps the best sequence here is to send a patch to kbuild adding the
> call-override function and calls to it to the main common Makefile. Then I
> can send individual subsystem patches dropping the individual CC = lines and
> similar. It will be 13 patches instead of 1 but will eventually result in
> the same thing.
>
> Paul, any thoughts?
>

That sounds good.

regards,
dan carpenter

2018-04-04 13:22:03

by Jiri Slaby

[permalink] [raw]
Subject: Re: [PATCH v2] tools: fix cross-compile var clobbering

On 01/07/2018, 10:40 PM, Martin Kelly wrote:
> From: Martin Kelly <[email protected]>
...
> --- a/tools/power/acpi/Makefile.config
> +++ b/tools/power/acpi/Makefile.config
> @@ -56,9 +56,6 @@ INSTALL_SCRIPT = ${INSTALL_PROGRAM}
> # to compile vs uClibc, that can be done here as well.
> CROSS = #/usr/i386-linux-uclibc/usr/bin/i386-uclibc-
> CROSS_COMPILE ?= $(CROSS)
> -CC = $(CROSS_COMPILE)gcc
> -LD = $(CROSS_COMPILE)gcc

This one makes difference -- acpi is special. This used to be:
LD = gcc

Now it is:
LD = ld

And due to that, we get:
ld: unrecognized option '-D_LINUX'

Should we do:
LD = $(CC)

or fix this elsewhere differently?

thanks,
--
js
suse labs

2018-04-04 16:33:02

by Martin Kelly

[permalink] [raw]
Subject: Re: [PATCH v2] tools: fix cross-compile var clobbering

On 04/04/2018 06:20 AM, Jiri Slaby wrote:
> On 01/07/2018, 10:40 PM, Martin Kelly wrote:
>> From: Martin Kelly <[email protected]>
> ...
>> --- a/tools/power/acpi/Makefile.config
>> +++ b/tools/power/acpi/Makefile.config
>> @@ -56,9 +56,6 @@ INSTALL_SCRIPT = ${INSTALL_PROGRAM}
>> # to compile vs uClibc, that can be done here as well.
>> CROSS = #/usr/i386-linux-uclibc/usr/bin/i386-uclibc-
>> CROSS_COMPILE ?= $(CROSS)
>> -CC = $(CROSS_COMPILE)gcc
>> -LD = $(CROSS_COMPILE)gcc
>
> This one makes difference -- acpi is special. This used to be:
> LD = gcc
>
> Now it is:
> LD = ld
>
> And due to that, we get:
> ld: unrecognized option '-D_LINUX'
>
> Should we do:
> LD = $(CC)
>
> or fix this elsewhere differently?
>
> thanks,
>
Yes, I think LD = $(CC) should work. $(CC) will be defaulted to
$(CROSS_COMPILE)gcc due to the call to $(call
allow-override,CC,$(CROSS_COMPILE)gcc) in
tools/scripts/Makefile.include. The allow-override function will
correctly handle env and command-line settings.

This will clobber any special $(LD) settings that the user has set, but
that was true as well for the acpi Makefile before this patch.

2018-04-24 09:02:51

by Jiri Slaby

[permalink] [raw]
Subject: [PATCH 1/1] tools: power/acpi, revert to LD = gcc

Commit 7ed1c1901fe5 (tools: fix cross-compile var clobbering) removed
setting of LD to $(CROSS_COMPILE)gcc. This broke build of acpica
(acpidump) in power/acpi:
ld: unrecognized option '-D_LINUX'

The tools pass CFLAGS to the linker (incl. -D_LINUX), so revert this
particular change and let LD be $(CC) again. Note that the old behaviour
was a bit different, it used $(CROSS_COMPILE)gcc which was eliminated by
the commit 7ed1c1901fe5. We use $(CC) for that reason.

Signed-off-by: Jiri Slaby <[email protected]>
Cc: Martin Kelly <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Len Brown <[email protected]>
Cc: Robert Moore <[email protected]>
Cc: Erik Schmauss <[email protected]>
Cc: [email protected]
Cc: [email protected]
---
tools/power/acpi/Makefile.config | 1 +
1 file changed, 1 insertion(+)

diff --git a/tools/power/acpi/Makefile.config b/tools/power/acpi/Makefile.config
index 2cccbba64418..f304be71c278 100644
--- a/tools/power/acpi/Makefile.config
+++ b/tools/power/acpi/Makefile.config
@@ -56,6 +56,7 @@ INSTALL_SCRIPT = ${INSTALL_PROGRAM}
# to compile vs uClibc, that can be done here as well.
CROSS = #/usr/i386-linux-uclibc/usr/bin/i386-uclibc-
CROSS_COMPILE ?= $(CROSS)
+LD = $(CC)
HOSTCC = gcc

# check if compiler option is supported
--
2.16.3


2018-04-24 16:40:59

by Martin Kelly

[permalink] [raw]
Subject: Re: [PATCH 1/1] tools: power/acpi, revert to LD = gcc

On Tue, Apr 24, 2018 at 12:43 AM, Jiri Slaby <[email protected]> wrote:
> Commit 7ed1c1901fe5 (tools: fix cross-compile var clobbering) removed
> setting of LD to $(CROSS_COMPILE)gcc. This broke build of acpica
> (acpidump) in power/acpi:
> ld: unrecognized option '-D_LINUX'
>
> The tools pass CFLAGS to the linker (incl. -D_LINUX), so revert this
> particular change and let LD be $(CC) again. Note that the old behaviour
> was a bit different, it used $(CROSS_COMPILE)gcc which was eliminated by
> the commit 7ed1c1901fe5. We use $(CC) for that reason.
>
> Signed-off-by: Jiri Slaby <[email protected]>
> Cc: Martin Kelly <[email protected]>
> Cc: "Rafael J. Wysocki" <[email protected]>
> Cc: Len Brown <[email protected]>
> Cc: Robert Moore <[email protected]>
> Cc: Erik Schmauss <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> ---
> tools/power/acpi/Makefile.config | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/tools/power/acpi/Makefile.config b/tools/power/acpi/Makefile.config
> index 2cccbba64418..f304be71c278 100644
> --- a/tools/power/acpi/Makefile.config
> +++ b/tools/power/acpi/Makefile.config
> @@ -56,6 +56,7 @@ INSTALL_SCRIPT = ${INSTALL_PROGRAM}
> # to compile vs uClibc, that can be done here as well.
> CROSS = #/usr/i386-linux-uclibc/usr/bin/i386-uclibc-
> CROSS_COMPILE ?= $(CROSS)
> +LD = $(CC)
> HOSTCC = gcc
>
> # check if compiler option is supported
> --
> 2.16.3
>

Reviewed-by: Martin Kelly <[email protected]>

Thanks for noticing this and sorry I missed it!

2018-04-30 08:02:07

by Rafael J. Wysocki

[permalink] [raw]
Subject: Re: [PATCH 1/1] tools: power/acpi, revert to LD = gcc

On Tuesday, April 24, 2018 9:43:44 AM CEST Jiri Slaby wrote:
> Commit 7ed1c1901fe5 (tools: fix cross-compile var clobbering) removed
> setting of LD to $(CROSS_COMPILE)gcc. This broke build of acpica
> (acpidump) in power/acpi:
> ld: unrecognized option '-D_LINUX'
>
> The tools pass CFLAGS to the linker (incl. -D_LINUX), so revert this
> particular change and let LD be $(CC) again. Note that the old behaviour
> was a bit different, it used $(CROSS_COMPILE)gcc which was eliminated by
> the commit 7ed1c1901fe5. We use $(CC) for that reason.
>
> Signed-off-by: Jiri Slaby <[email protected]>
> Cc: Martin Kelly <[email protected]>
> Cc: "Rafael J. Wysocki" <[email protected]>
> Cc: Len Brown <[email protected]>
> Cc: Robert Moore <[email protected]>
> Cc: Erik Schmauss <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> ---
> tools/power/acpi/Makefile.config | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/tools/power/acpi/Makefile.config b/tools/power/acpi/Makefile.config
> index 2cccbba64418..f304be71c278 100644
> --- a/tools/power/acpi/Makefile.config
> +++ b/tools/power/acpi/Makefile.config
> @@ -56,6 +56,7 @@ INSTALL_SCRIPT = ${INSTALL_PROGRAM}
> # to compile vs uClibc, that can be done here as well.
> CROSS = #/usr/i386-linux-uclibc/usr/bin/i386-uclibc-
> CROSS_COMPILE ?= $(CROSS)
> +LD = $(CC)
> HOSTCC = gcc
>
> # check if compiler option is supported
>

Applied, thanks!