* [PATCH v2] tools/sched_ext: Improve cross-compilation support in Makefile
@ 2025-04-15 5:46 yangsonghua
2025-04-15 6:52 ` Andrea Righi
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: yangsonghua @ 2025-04-15 5:46 UTC (permalink / raw)
To: tj, void, arighi, changwoo; +Cc: linux-kernel, sched-ext, yangsonghua
Modify the tools/sched_ext/Makefile to better handle cross-compilation
environments by:
1. Adjusted `HOST_OUTPUT_DIR` to be relative to `$(OBJ_DIR)`, ensuring
correct path handling during host tool building when cross-compile
(HOST_OUTPUT_DIR now points to $(OBJ_DIR)/host-tools)
2. Properly propagate CROSS_COMPILE to libbpf sub-make invocation
3. Add missing $(HOST_BPFOBJ) build rule with proper host toolchain flags
(ARCH=, CROSS_COMPILE=, explicit HOSTCC/HOSTLD)
4. Consistently quote $(HOSTCC) in bpftool build rule
The changes ensure proper cross-compilation behavior while maintaining
backward compatibility with native builds. Host tools are now correctly
built with the host toolchain while target binaries use the cross-toolchain.
Signed-off-by: yangsonghua <yangsonghua@lixiang.com>
------
v2:
- keep HOST_BUILD_DIR and LDFLAGS unchanged
- change the title prefix "sched_ext" to "tools/sched_ext"
v1:
- https://lore.kernel.org/lkml/20250414081436.2574882-1-yangsonghua@lixiang.com/
---
tools/sched_ext/Makefile | 19 +++++++++++++++----
1 file changed, 15 insertions(+), 4 deletions(-)
diff --git a/tools/sched_ext/Makefile b/tools/sched_ext/Makefile
index ca3815e572d8..eb85f3762a1f 100644
--- a/tools/sched_ext/Makefile
+++ b/tools/sched_ext/Makefile
@@ -62,7 +62,7 @@ BINDIR := $(OUTPUT_DIR)/bin
BPFOBJ := $(BPFOBJ_DIR)/libbpf.a
ifneq ($(CROSS_COMPILE),)
HOST_BUILD_DIR := $(OBJ_DIR)/host
-HOST_OUTPUT_DIR := host-tools
+HOST_OUTPUT_DIR := $(OBJ_DIR)/host-tools
HOST_INCLUDE_DIR := $(HOST_OUTPUT_DIR)/include
else
HOST_BUILD_DIR := $(OBJ_DIR)
@@ -136,14 +136,25 @@ $(MAKE_DIRS):
$(BPFOBJ): $(wildcard $(BPFDIR)/*.[ch] $(BPFDIR)/Makefile) \
$(APIDIR)/linux/bpf.h \
| $(OBJ_DIR)/libbpf
- $(Q)$(MAKE) $(submake_extras) -C $(BPFDIR) OUTPUT=$(OBJ_DIR)/libbpf/ \
+ $(Q)$(MAKE) $(submake_extras) CROSS_COMPILE=$(CROSS_COMPILE) \
+ -C $(BPFDIR) OUTPUT=$(OBJ_DIR)/libbpf/ \
EXTRA_CFLAGS='-g -O0 -fPIC' \
+ LDFLAGS="$(LDFLAGS)" \
DESTDIR=$(OUTPUT_DIR) prefix= all install_headers
+$(HOST_BPFOBJ): $(wildcard $(BPFDIR)/*.[ch] $(BPFDIR)/Makefile) \
+ $(APIDIR)/linux/bpf.h \
+ | $(HOST_BUILD_DIR)/libbpf
+ $(Q)$(MAKE) $(submake_extras) -C $(BPFDIR) \
+ OUTPUT=$(HOST_BUILD_DIR)/libbpf/ \
+ ARCH= CROSS_COMPILE= CC="$(HOSTCC)" LD=$(HOSTLD) \
+ EXTRA_CFLAGS='-g -O0 -fPIC' \
+ DESTDIR=$(HOST_OUTPUT_DIR) prefix= all install_headers
+
$(DEFAULT_BPFTOOL): $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile) \
$(HOST_BPFOBJ) | $(HOST_BUILD_DIR)/bpftool
$(Q)$(MAKE) $(submake_extras) -C $(BPFTOOLDIR) \
- ARCH= CROSS_COMPILE= CC=$(HOSTCC) LD=$(HOSTLD) \
+ ARCH= CROSS_COMPILE= CC="$(HOSTCC)" LD=$(HOSTLD) \
EXTRA_CFLAGS='-g -O0' \
OUTPUT=$(HOST_BUILD_DIR)/bpftool/ \
LIBBPF_OUTPUT=$(HOST_BUILD_DIR)/libbpf/ \
@@ -185,7 +196,7 @@ $(addprefix $(BINDIR)/,$(c-sched-targets)): \
$(SCX_COMMON_DEPS)
$(eval sched=$(notdir $@))
$(CC) $(CFLAGS) -c $(sched).c -o $(SCXOBJ_DIR)/$(sched).o
- $(CC) -o $@ $(SCXOBJ_DIR)/$(sched).o $(HOST_BPFOBJ) $(LDFLAGS)
+ $(CC) -o $@ $(SCXOBJ_DIR)/$(sched).o $(BPFOBJ) $(LDFLAGS)
$(c-sched-targets): %: $(BINDIR)/%
--
2.25.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH v2] tools/sched_ext: Improve cross-compilation support in Makefile
2025-04-15 5:46 [PATCH v2] tools/sched_ext: Improve cross-compilation support in Makefile yangsonghua
@ 2025-04-15 6:52 ` Andrea Righi
2025-04-15 6:56 ` Andrea Righi
2025-04-15 14:57 ` Tejun Heo
2 siblings, 0 replies; 5+ messages in thread
From: Andrea Righi @ 2025-04-15 6:52 UTC (permalink / raw)
To: yangsonghua; +Cc: tj, void, changwoo, linux-kernel, sched-ext, yangsonghua
On Tue, Apr 15, 2025 at 01:46:42PM +0800, yangsonghua wrote:
> Modify the tools/sched_ext/Makefile to better handle cross-compilation
> environments by:
>
> 1. Adjusted `HOST_OUTPUT_DIR` to be relative to `$(OBJ_DIR)`, ensuring
> correct path handling during host tool building when cross-compile
> (HOST_OUTPUT_DIR now points to $(OBJ_DIR)/host-tools)
> 2. Properly propagate CROSS_COMPILE to libbpf sub-make invocation
> 3. Add missing $(HOST_BPFOBJ) build rule with proper host toolchain flags
> (ARCH=, CROSS_COMPILE=, explicit HOSTCC/HOSTLD)
> 4. Consistently quote $(HOSTCC) in bpftool build rule
>
> The changes ensure proper cross-compilation behavior while maintaining
> backward compatibility with native builds. Host tools are now correctly
> built with the host toolchain while target binaries use the cross-toolchain.
>
> Signed-off-by: yangsonghua <yangsonghua@lixiang.com>
It makes things better with this applied, at least it starts the cross
build, but I'm still getting troubles with libelf and zlib:
$ make CROSS_COMPILE=aarch64-linux-gnu- ARCH=arm64
...
LINK /home/arighi/src/linux/tools/sched_ext/build/obj/libbpf/libbpf.so.1.6.0
/usr/lib/gcc-cross/aarch64-linux-gnu/14/../../../../aarch64-linux-gnu/bin/ld: cannot find -lelf: No such file or directory
/usr/lib/gcc-cross/aarch64-linux-gnu/14/../../../../aarch64-linux-gnu/bin/ld: cannot find -lz: No such file or directory
Which distro are you using and what command are you running exactly to test
the cross build?
Thanks,
-Andrea
>
> ------
> v2:
> - keep HOST_BUILD_DIR and LDFLAGS unchanged
> - change the title prefix "sched_ext" to "tools/sched_ext"
>
> v1:
> - https://lore.kernel.org/lkml/20250414081436.2574882-1-yangsonghua@lixiang.com/
> ---
> tools/sched_ext/Makefile | 19 +++++++++++++++----
> 1 file changed, 15 insertions(+), 4 deletions(-)
>
> diff --git a/tools/sched_ext/Makefile b/tools/sched_ext/Makefile
> index ca3815e572d8..eb85f3762a1f 100644
> --- a/tools/sched_ext/Makefile
> +++ b/tools/sched_ext/Makefile
> @@ -62,7 +62,7 @@ BINDIR := $(OUTPUT_DIR)/bin
> BPFOBJ := $(BPFOBJ_DIR)/libbpf.a
> ifneq ($(CROSS_COMPILE),)
> HOST_BUILD_DIR := $(OBJ_DIR)/host
> -HOST_OUTPUT_DIR := host-tools
> +HOST_OUTPUT_DIR := $(OBJ_DIR)/host-tools
> HOST_INCLUDE_DIR := $(HOST_OUTPUT_DIR)/include
> else
> HOST_BUILD_DIR := $(OBJ_DIR)
> @@ -136,14 +136,25 @@ $(MAKE_DIRS):
> $(BPFOBJ): $(wildcard $(BPFDIR)/*.[ch] $(BPFDIR)/Makefile) \
> $(APIDIR)/linux/bpf.h \
> | $(OBJ_DIR)/libbpf
> - $(Q)$(MAKE) $(submake_extras) -C $(BPFDIR) OUTPUT=$(OBJ_DIR)/libbpf/ \
> + $(Q)$(MAKE) $(submake_extras) CROSS_COMPILE=$(CROSS_COMPILE) \
> + -C $(BPFDIR) OUTPUT=$(OBJ_DIR)/libbpf/ \
> EXTRA_CFLAGS='-g -O0 -fPIC' \
> + LDFLAGS="$(LDFLAGS)" \
> DESTDIR=$(OUTPUT_DIR) prefix= all install_headers
>
> +$(HOST_BPFOBJ): $(wildcard $(BPFDIR)/*.[ch] $(BPFDIR)/Makefile) \
> + $(APIDIR)/linux/bpf.h \
> + | $(HOST_BUILD_DIR)/libbpf
> + $(Q)$(MAKE) $(submake_extras) -C $(BPFDIR) \
> + OUTPUT=$(HOST_BUILD_DIR)/libbpf/ \
> + ARCH= CROSS_COMPILE= CC="$(HOSTCC)" LD=$(HOSTLD) \
> + EXTRA_CFLAGS='-g -O0 -fPIC' \
> + DESTDIR=$(HOST_OUTPUT_DIR) prefix= all install_headers
> +
> $(DEFAULT_BPFTOOL): $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile) \
> $(HOST_BPFOBJ) | $(HOST_BUILD_DIR)/bpftool
> $(Q)$(MAKE) $(submake_extras) -C $(BPFTOOLDIR) \
> - ARCH= CROSS_COMPILE= CC=$(HOSTCC) LD=$(HOSTLD) \
> + ARCH= CROSS_COMPILE= CC="$(HOSTCC)" LD=$(HOSTLD) \
> EXTRA_CFLAGS='-g -O0' \
> OUTPUT=$(HOST_BUILD_DIR)/bpftool/ \
> LIBBPF_OUTPUT=$(HOST_BUILD_DIR)/libbpf/ \
> @@ -185,7 +196,7 @@ $(addprefix $(BINDIR)/,$(c-sched-targets)): \
> $(SCX_COMMON_DEPS)
> $(eval sched=$(notdir $@))
> $(CC) $(CFLAGS) -c $(sched).c -o $(SCXOBJ_DIR)/$(sched).o
> - $(CC) -o $@ $(SCXOBJ_DIR)/$(sched).o $(HOST_BPFOBJ) $(LDFLAGS)
> + $(CC) -o $@ $(SCXOBJ_DIR)/$(sched).o $(BPFOBJ) $(LDFLAGS)
>
> $(c-sched-targets): %: $(BINDIR)/%
>
> --
> 2.25.1
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2] tools/sched_ext: Improve cross-compilation support in Makefile
2025-04-15 5:46 [PATCH v2] tools/sched_ext: Improve cross-compilation support in Makefile yangsonghua
2025-04-15 6:52 ` Andrea Righi
@ 2025-04-15 6:56 ` Andrea Righi
2025-04-15 14:57 ` Tejun Heo
2 siblings, 0 replies; 5+ messages in thread
From: Andrea Righi @ 2025-04-15 6:56 UTC (permalink / raw)
To: yangsonghua; +Cc: tj, void, changwoo, linux-kernel, sched-ext, yangsonghua
On Tue, Apr 15, 2025 at 01:46:42PM +0800, yangsonghua wrote:
...
> ---
> tools/sched_ext/Makefile | 19 +++++++++++++++----
> 1 file changed, 15 insertions(+), 4 deletions(-)
>
> diff --git a/tools/sched_ext/Makefile b/tools/sched_ext/Makefile
> index ca3815e572d8..eb85f3762a1f 100644
> --- a/tools/sched_ext/Makefile
> +++ b/tools/sched_ext/Makefile
> @@ -62,7 +62,7 @@ BINDIR := $(OUTPUT_DIR)/bin
> BPFOBJ := $(BPFOBJ_DIR)/libbpf.a
> ifneq ($(CROSS_COMPILE),)
> HOST_BUILD_DIR := $(OBJ_DIR)/host
> -HOST_OUTPUT_DIR := host-tools
> +HOST_OUTPUT_DIR := $(OBJ_DIR)/host-tools
> HOST_INCLUDE_DIR := $(HOST_OUTPUT_DIR)/include
> else
> HOST_BUILD_DIR := $(OBJ_DIR)
> @@ -136,14 +136,25 @@ $(MAKE_DIRS):
> $(BPFOBJ): $(wildcard $(BPFDIR)/*.[ch] $(BPFDIR)/Makefile) \
> $(APIDIR)/linux/bpf.h \
> | $(OBJ_DIR)/libbpf
> - $(Q)$(MAKE) $(submake_extras) -C $(BPFDIR) OUTPUT=$(OBJ_DIR)/libbpf/ \
> + $(Q)$(MAKE) $(submake_extras) CROSS_COMPILE=$(CROSS_COMPILE) \
Are we missing ARCH=$(ARCH) here?
Thanks,
-Andrea
> + -C $(BPFDIR) OUTPUT=$(OBJ_DIR)/libbpf/ \
> EXTRA_CFLAGS='-g -O0 -fPIC' \
> + LDFLAGS="$(LDFLAGS)" \
> DESTDIR=$(OUTPUT_DIR) prefix= all install_headers
>
> +$(HOST_BPFOBJ): $(wildcard $(BPFDIR)/*.[ch] $(BPFDIR)/Makefile) \
> + $(APIDIR)/linux/bpf.h \
> + | $(HOST_BUILD_DIR)/libbpf
> + $(Q)$(MAKE) $(submake_extras) -C $(BPFDIR) \
> + OUTPUT=$(HOST_BUILD_DIR)/libbpf/ \
> + ARCH= CROSS_COMPILE= CC="$(HOSTCC)" LD=$(HOSTLD) \
> + EXTRA_CFLAGS='-g -O0 -fPIC' \
> + DESTDIR=$(HOST_OUTPUT_DIR) prefix= all install_headers
> +
> $(DEFAULT_BPFTOOL): $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile) \
> $(HOST_BPFOBJ) | $(HOST_BUILD_DIR)/bpftool
> $(Q)$(MAKE) $(submake_extras) -C $(BPFTOOLDIR) \
> - ARCH= CROSS_COMPILE= CC=$(HOSTCC) LD=$(HOSTLD) \
> + ARCH= CROSS_COMPILE= CC="$(HOSTCC)" LD=$(HOSTLD) \
> EXTRA_CFLAGS='-g -O0' \
> OUTPUT=$(HOST_BUILD_DIR)/bpftool/ \
> LIBBPF_OUTPUT=$(HOST_BUILD_DIR)/libbpf/ \
> @@ -185,7 +196,7 @@ $(addprefix $(BINDIR)/,$(c-sched-targets)): \
> $(SCX_COMMON_DEPS)
> $(eval sched=$(notdir $@))
> $(CC) $(CFLAGS) -c $(sched).c -o $(SCXOBJ_DIR)/$(sched).o
> - $(CC) -o $@ $(SCXOBJ_DIR)/$(sched).o $(HOST_BPFOBJ) $(LDFLAGS)
> + $(CC) -o $@ $(SCXOBJ_DIR)/$(sched).o $(BPFOBJ) $(LDFLAGS)
>
> $(c-sched-targets): %: $(BINDIR)/%
>
> --
> 2.25.1
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2] tools/sched_ext: Improve cross-compilation support in Makefile
2025-04-15 5:46 [PATCH v2] tools/sched_ext: Improve cross-compilation support in Makefile yangsonghua
2025-04-15 6:52 ` Andrea Righi
2025-04-15 6:56 ` Andrea Righi
@ 2025-04-15 14:57 ` Tejun Heo
2025-04-16 1:24 ` Eric yang
2 siblings, 1 reply; 5+ messages in thread
From: Tejun Heo @ 2025-04-15 14:57 UTC (permalink / raw)
To: yangsonghua; +Cc: void, arighi, changwoo, linux-kernel, sched-ext, yangsonghua
On Tue, Apr 15, 2025 at 01:46:42PM +0800, yangsonghua wrote:
> Modify the tools/sched_ext/Makefile to better handle cross-compilation
> environments by:
>
> 1. Adjusted `HOST_OUTPUT_DIR` to be relative to `$(OBJ_DIR)`, ensuring
> correct path handling during host tool building when cross-compile
> (HOST_OUTPUT_DIR now points to $(OBJ_DIR)/host-tools)
> 2. Properly propagate CROSS_COMPILE to libbpf sub-make invocation
> 3. Add missing $(HOST_BPFOBJ) build rule with proper host toolchain flags
> (ARCH=, CROSS_COMPILE=, explicit HOSTCC/HOSTLD)
> 4. Consistently quote $(HOSTCC) in bpftool build rule
>
> The changes ensure proper cross-compilation behavior while maintaining
> backward compatibility with native builds. Host tools are now correctly
> built with the host toolchain while target binaries use the cross-toolchain.
>
> Signed-off-by: yangsonghua <yangsonghua@lixiang.com>
I already applied v1, so please send the updates as incremental changes
atop.
Thanks.
--
tejun
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2] tools/sched_ext: Improve cross-compilation support in Makefile
2025-04-15 14:57 ` Tejun Heo
@ 2025-04-16 1:24 ` Eric yang
0 siblings, 0 replies; 5+ messages in thread
From: Eric yang @ 2025-04-16 1:24 UTC (permalink / raw)
To: Tejun Heo; +Cc: void, arighi, changwoo, linux-kernel, sched-ext, yangsonghua
Okay, v1 works well. I misunderstood your intentions last time. Please
disregard v2.
Thanks
Eric
Tejun Heo <tj@kernel.org> 于2025年4月15日周二 22:57写道：
>
> On Tue, Apr 15, 2025 at 01:46:42PM +0800, yangsonghua wrote:
> > Modify the tools/sched_ext/Makefile to better handle cross-compilation
> > environments by:
> >
> > 1. Adjusted `HOST_OUTPUT_DIR` to be relative to `$(OBJ_DIR)`, ensuring
> > correct path handling during host tool building when cross-compile
> > (HOST_OUTPUT_DIR now points to $(OBJ_DIR)/host-tools)
> > 2. Properly propagate CROSS_COMPILE to libbpf sub-make invocation
> > 3. Add missing $(HOST_BPFOBJ) build rule with proper host toolchain flags
> > (ARCH=, CROSS_COMPILE=, explicit HOSTCC/HOSTLD)
> > 4. Consistently quote $(HOSTCC) in bpftool build rule
> >
> > The changes ensure proper cross-compilation behavior while maintaining
> > backward compatibility with native builds. Host tools are now correctly
> > built with the host toolchain while target binaries use the cross-toolchain.
> >
> > Signed-off-by: yangsonghua <yangsonghua@lixiang.com>
>
> I already applied v1, so please send the updates as incremental changes
> atop.
>
> Thanks.
>
> --
> tejun
^ permalink raw reply [flat|nested] 5+ messages in thread
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2025-04-15 5:46 [PATCH v2] tools/sched_ext: Improve cross-compilation support in Makefile yangsonghua
2025-04-15 6:52 ` Andrea Righi
2025-04-15 6:56 ` Andrea Righi
2025-04-15 14:57 ` Tejun Heo
2025-04-16 1:24 ` Eric yang
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