* [PATCH 1/9] hexagon: uapi: Fix structure alignment attribute
2026-02-27 6:37 [PATCH 0/9] kbuild: uapi: remove usage of toolchain headers Thomas Weißschuh
@ 2026-02-27 6:37 ` Thomas Weißschuh
2026-02-27 6:38 ` [PATCH 2/9] kbuild: uapi: test linux/bpf_perf_event.h on powerpc Thomas Weißschuh
` (11 subsequent siblings)
12 siblings, 0 replies; 16+ messages in thread
From: Thomas Weißschuh @ 2026-02-27 6:37 UTC (permalink / raw)
To: Nathan Chancellor, Nicolas Schier, Brian Cain
Cc: linux-kbuild, linux-kernel, Arnd Bergmann, linux-hexagon,
Thomas Weißschuh, Thomas Weißschuh
From: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
__aligned() is a kernel macro, which is not available in UAPI headers.
Use the compiler-provided alignment attribute directly.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
---
arch/hexagon/include/uapi/asm/sigcontext.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/hexagon/include/uapi/asm/sigcontext.h b/arch/hexagon/include/uapi/asm/sigcontext.h
index 7171edb1b8b7..179a97041b59 100644
--- a/arch/hexagon/include/uapi/asm/sigcontext.h
+++ b/arch/hexagon/include/uapi/asm/sigcontext.h
@@ -29,6 +29,6 @@
*/
struct sigcontext {
struct user_regs_struct sc_regs;
-} __aligned(8);
+} __attribute__((aligned(8)));
#endif
--
2.53.0
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH 2/9] kbuild: uapi: test linux/bpf_perf_event.h on powerpc
2026-02-27 6:37 [PATCH 0/9] kbuild: uapi: remove usage of toolchain headers Thomas Weißschuh
2026-02-27 6:37 ` [PATCH 1/9] hexagon: uapi: Fix structure alignment attribute Thomas Weißschuh
@ 2026-02-27 6:38 ` Thomas Weißschuh
2026-02-27 6:38 ` [PATCH 3/9] kbuild: uapi: deduplicate linux/bpf_perf_event.h exclusions Thomas Weißschuh
` (10 subsequent siblings)
12 siblings, 0 replies; 16+ messages in thread
From: Thomas Weißschuh @ 2026-02-27 6:38 UTC (permalink / raw)
To: Nathan Chancellor, Nicolas Schier, Brian Cain
Cc: linux-kbuild, linux-kernel, Arnd Bergmann, linux-hexagon,
Thomas Weißschuh
This header works now, so test it.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---
usr/include/Makefile | 4 ----
1 file changed, 4 deletions(-)
diff --git a/usr/include/Makefile b/usr/include/Makefile
index 6d86a53c6f0a..595996eefcc6 100644
--- a/usr/include/Makefile
+++ b/usr/include/Makefile
@@ -56,10 +56,6 @@ ifeq ($(SRCARCH),openrisc)
no-header-test += linux/bpf_perf_event.h
endif
-ifeq ($(SRCARCH),powerpc)
-no-header-test += linux/bpf_perf_event.h
-endif
-
ifeq ($(SRCARCH),sparc)
no-header-test += asm/uctx.h
no-header-test += asm/fbio.h
--
2.53.0
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH 3/9] kbuild: uapi: deduplicate linux/bpf_perf_event.h exclusions
2026-02-27 6:37 [PATCH 0/9] kbuild: uapi: remove usage of toolchain headers Thomas Weißschuh
2026-02-27 6:37 ` [PATCH 1/9] hexagon: uapi: Fix structure alignment attribute Thomas Weißschuh
2026-02-27 6:38 ` [PATCH 2/9] kbuild: uapi: test linux/bpf_perf_event.h on powerpc Thomas Weißschuh
@ 2026-02-27 6:38 ` Thomas Weißschuh
2026-02-27 6:38 ` [PATCH 4/9] kbuild: uapi: completely exclude linux/bpf_perf_event.h on nios2 Thomas Weißschuh
` (9 subsequent siblings)
12 siblings, 0 replies; 16+ messages in thread
From: Thomas Weißschuh @ 2026-02-27 6:38 UTC (permalink / raw)
To: Nathan Chancellor, Nicolas Schier, Brian Cain
Cc: linux-kbuild, linux-kernel, Arnd Bergmann, linux-hexagon,
Thomas Weißschuh
This header is excluded for multiple architectures.
Use a single exclusion for all of them.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---
usr/include/Makefile | 10 +---------
1 file changed, 1 insertion(+), 9 deletions(-)
diff --git a/usr/include/Makefile b/usr/include/Makefile
index 595996eefcc6..ae365d32269a 100644
--- a/usr/include/Makefile
+++ b/usr/include/Makefile
@@ -48,11 +48,7 @@ no-header-test += xen/privcmd.h
# More headers are broken in some architectures
-ifeq ($(SRCARCH),arc)
-no-header-test += linux/bpf_perf_event.h
-endif
-
-ifeq ($(SRCARCH),openrisc)
+ifneq ($(filter arc openrisc xtensa, $(SRCARCH)),)
no-header-test += linux/bpf_perf_event.h
endif
@@ -61,10 +57,6 @@ no-header-test += asm/uctx.h
no-header-test += asm/fbio.h
endif
-ifeq ($(SRCARCH),xtensa)
-no-header-test += linux/bpf_perf_event.h
-endif
-
# asm-generic/*.h is used by asm/*.h, and should not be included directly
no-header-test += asm-generic/%
--
2.53.0
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH 4/9] kbuild: uapi: completely exclude linux/bpf_perf_event.h on nios2
2026-02-27 6:37 [PATCH 0/9] kbuild: uapi: remove usage of toolchain headers Thomas Weißschuh
` (2 preceding siblings ...)
2026-02-27 6:38 ` [PATCH 3/9] kbuild: uapi: deduplicate linux/bpf_perf_event.h exclusions Thomas Weißschuh
@ 2026-02-27 6:38 ` Thomas Weißschuh
2026-02-27 6:38 ` [PATCH 5/9] kbuild: uapi: only use dummy-include for headers which use libc Thomas Weißschuh
` (8 subsequent siblings)
12 siblings, 0 replies; 16+ messages in thread
From: Thomas Weißschuh @ 2026-02-27 6:38 UTC (permalink / raw)
To: Nathan Chancellor, Nicolas Schier, Brian Cain
Cc: linux-kbuild, linux-kernel, Arnd Bergmann, linux-hexagon,
Thomas Weißschuh
This header is actually not buildable on nios. As nobody built nios2
with CONFIG_CC_CAN_LINK=y so far, this produced no errors.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---
usr/include/Makefile | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/usr/include/Makefile b/usr/include/Makefile
index ae365d32269a..a8619aa85c87 100644
--- a/usr/include/Makefile
+++ b/usr/include/Makefile
@@ -48,7 +48,7 @@ no-header-test += xen/privcmd.h
# More headers are broken in some architectures
-ifneq ($(filter arc openrisc xtensa, $(SRCARCH)),)
+ifneq ($(filter arc openrisc xtensa nios2, $(SRCARCH)),)
no-header-test += linux/bpf_perf_event.h
endif
@@ -128,7 +128,6 @@ endif
ifeq ($(SRCARCH),nios2)
uses-libc += asm/ptrace.h
-uses-libc += linux/bpf_perf_event.h
endif
ifeq ($(SRCARCH),s390)
--
2.53.0
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH 5/9] kbuild: uapi: only use dummy-include for headers which use libc
2026-02-27 6:37 [PATCH 0/9] kbuild: uapi: remove usage of toolchain headers Thomas Weißschuh
` (3 preceding siblings ...)
2026-02-27 6:38 ` [PATCH 4/9] kbuild: uapi: completely exclude linux/bpf_perf_event.h on nios2 Thomas Weißschuh
@ 2026-02-27 6:38 ` Thomas Weißschuh
2026-02-27 6:38 ` [PATCH 6/9] kbuild: uapi: provide stub includes for some libc headers Thomas Weißschuh
` (7 subsequent siblings)
12 siblings, 0 replies; 16+ messages in thread
From: Thomas Weißschuh @ 2026-02-27 6:38 UTC (permalink / raw)
To: Nathan Chancellor, Nicolas Schier, Brian Cain
Cc: linux-kbuild, linux-kernel, Arnd Bergmann, linux-hexagon,
Thomas Weißschuh
The headers which do not rely on libc are using built using -nostdinc.
For them the dummy headers are pointless.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---
usr/include/Makefile | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/usr/include/Makefile b/usr/include/Makefile
index a8619aa85c87..fdc79cffcc97 100644
--- a/usr/include/Makefile
+++ b/usr/include/Makefile
@@ -8,7 +8,7 @@
# We cannot go as far as adding -Wpedantic since it emits too many warnings.
UAPI_CFLAGS := -std=c90 -Werror=implicit-function-declaration
-override c_flags = $(KBUILD_USERCFLAGS) $(UAPI_CFLAGS) -Wp,-MMD,$(depfile) -I $(obj) -I $(srctree)/usr/dummy-include
+override c_flags = $(KBUILD_USERCFLAGS) $(UAPI_CFLAGS) -Wp,-MMD,$(depfile) -I $(obj)
# The following are excluded for now because they fail to build.
#
@@ -145,7 +145,7 @@ target-can-compile = $(and $(filter-out $(no-header-test), $*.h), \
quiet_cmd_hdrtest = HDRTEST $<
cmd_hdrtest = \
$(CC) $(c_flags) -fsyntax-only -Werror -x c /dev/null \
- $(if $(target-no-libc), -nostdinc) \
+ $(if $(target-no-libc), -nostdinc, -I $(srctree)/usr/dummy-include) \
$(if $(target-can-compile), -include $< -include $<); \
$(PERL) $(src)/headers_check.pl $(obj) $<; \
touch $@
--
2.53.0
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH 6/9] kbuild: uapi: provide stub includes for some libc headers
2026-02-27 6:37 [PATCH 0/9] kbuild: uapi: remove usage of toolchain headers Thomas Weißschuh
` (4 preceding siblings ...)
2026-02-27 6:38 ` [PATCH 5/9] kbuild: uapi: only use dummy-include for headers which use libc Thomas Weißschuh
@ 2026-02-27 6:38 ` Thomas Weißschuh
2026-02-27 6:38 ` [PATCH 7/9] kbuild: uapi: use custom stub headers instead of libc ones Thomas Weißschuh
` (6 subsequent siblings)
12 siblings, 0 replies; 16+ messages in thread
From: Thomas Weißschuh @ 2026-02-27 6:38 UTC (permalink / raw)
To: Nathan Chancellor, Nicolas Schier, Brian Cain
Cc: linux-kbuild, linux-kernel, Arnd Bergmann, linux-hexagon,
Thomas Weißschuh
Some UAPI headers incorrectly use libc headers. To compile-test these
UAPI headers, their respective libc dependencies need to be present.
Not all kernel toolchains provide these headers, reducing test coverage.
Introduce some stub headers which provide just enough symbols to test
all UAPI headers. Most headers are empty anyways, as their symbols are
only used in macros which are not actually evaluated.
As these headers are only ever used with newer kernel toolchains, they
can defer to compiler builtins in many cases.
As more UAPI headers are cleaned up to not require these stubs anymore,
they can be removed again.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---
usr/dummy-include/endian.h | 0
usr/dummy-include/limits.h | 8 ++++++++
usr/dummy-include/netinet/if_ether.h | 0
usr/dummy-include/netinet/in.h | 0
usr/dummy-include/stddef.h | 8 ++++++++
usr/dummy-include/stdint.h | 17 +++++++++++++++++
usr/dummy-include/string.h | 12 ++++++++++++
usr/dummy-include/sys/ioctl.h | 0
usr/dummy-include/sys/socket.h | 12 ++++++++++++
usr/dummy-include/sys/time.h | 3 +++
usr/dummy-include/sys/types.h | 0
usr/dummy-include/time.h | 0
usr/dummy-include/unistd.h | 0
13 files changed, 60 insertions(+)
diff --git a/usr/dummy-include/endian.h b/usr/dummy-include/endian.h
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/usr/dummy-include/limits.h b/usr/dummy-include/limits.h
new file mode 100644
index 000000000000..49b17c10c7b6
--- /dev/null
+++ b/usr/dummy-include/limits.h
@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _DUMMY_LIMITS_H
+#define _DUMMY_LIMITS_H
+
+#define INT_MAX ((int)(~0U >> 1))
+#define INT_MIN (-INT_MAX - 1)
+
+#endif /* _DUMMY_LIMITS_H */
diff --git a/usr/dummy-include/netinet/if_ether.h b/usr/dummy-include/netinet/if_ether.h
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/usr/dummy-include/netinet/in.h b/usr/dummy-include/netinet/in.h
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/usr/dummy-include/stddef.h b/usr/dummy-include/stddef.h
new file mode 100644
index 000000000000..a61703d1c896
--- /dev/null
+++ b/usr/dummy-include/stddef.h
@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _DUMMY_STDDEF_H
+#define _DUMMY_STDDEF_H
+
+#define offsetof(TYPE, MEMBER) __builtin_offsetof(TYPE, MEMBER)
+#define NULL ((void *)0)
+
+#endif /* _DUMMY_STDDEF_H */
diff --git a/usr/dummy-include/stdint.h b/usr/dummy-include/stdint.h
new file mode 100644
index 000000000000..93b1962fd08c
--- /dev/null
+++ b/usr/dummy-include/stdint.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _DUMMY_STDINT_H
+#define _DUMMY_STDINT_H
+
+#include <linux/types.h>
+
+typedef __u64 uint64_t;
+typedef __u32 uint32_t;
+typedef __u16 uint16_t;
+typedef __u8 uint8_t;
+
+typedef __s64 int64_t;
+typedef __s32 int32_t;
+typedef __s16 int16_t;
+typedef __s8 int8_t;
+
+#endif /* _DUMMY_STDINT_H */
diff --git a/usr/dummy-include/string.h b/usr/dummy-include/string.h
new file mode 100644
index 000000000000..e059808d309a
--- /dev/null
+++ b/usr/dummy-include/string.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _DUMMY_STRING_H
+#define _DUMMY_STRING_H
+
+#include <stddef.h>
+
+#define memset(_s, _c, _n) __builtin_memset(_s, _c, _n)
+#define memcpy(_dest, _src, _n) __builtin_memcpy(_dest, _src, _n)
+
+#define strlen(_s) __builtin_strlen(_s)
+
+#endif /* _DUMMY_STRING_H */
diff --git a/usr/dummy-include/sys/ioctl.h b/usr/dummy-include/sys/ioctl.h
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/usr/dummy-include/sys/socket.h b/usr/dummy-include/sys/socket.h
new file mode 100644
index 000000000000..748751f9e53e
--- /dev/null
+++ b/usr/dummy-include/sys/socket.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _DUMMY_SYS_SOCKET_H
+#define _DUMMY_SYS_SOCKET_H
+
+#include <linux/socket.h>
+
+struct sockaddr {
+ __kernel_sa_family_t sa_family; /* address family, AF_xxx */
+ char sa_data[14]; /* 14 bytes of protocol address */
+};
+
+#endif /* _DUMMY_SYS_SOCKET_H */
diff --git a/usr/dummy-include/sys/time.h b/usr/dummy-include/sys/time.h
new file mode 100644
index 000000000000..9817b8afb1a6
--- /dev/null
+++ b/usr/dummy-include/sys/time.h
@@ -0,0 +1,3 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <linux/time.h>
diff --git a/usr/dummy-include/sys/types.h b/usr/dummy-include/sys/types.h
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/usr/dummy-include/time.h b/usr/dummy-include/time.h
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/usr/dummy-include/unistd.h b/usr/dummy-include/unistd.h
new file mode 100644
index 000000000000..e69de29bb2d1
--
2.53.0
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH 7/9] kbuild: uapi: use custom stub headers instead of libc ones
2026-02-27 6:37 [PATCH 0/9] kbuild: uapi: remove usage of toolchain headers Thomas Weißschuh
` (5 preceding siblings ...)
2026-02-27 6:38 ` [PATCH 6/9] kbuild: uapi: provide stub includes for some libc headers Thomas Weißschuh
@ 2026-02-27 6:38 ` Thomas Weißschuh
2026-02-27 6:38 ` [PATCH 8/9] kbuild: uapi: simplify libc dependency logic Thomas Weißschuh
` (5 subsequent siblings)
12 siblings, 0 replies; 16+ messages in thread
From: Thomas Weißschuh @ 2026-02-27 6:38 UTC (permalink / raw)
To: Nathan Chancellor, Nicolas Schier, Brian Cain
Cc: linux-kbuild, linux-kernel, Arnd Bergmann, linux-hexagon,
Thomas Weißschuh
Now that custom stub headers are provided for all libc headers used from
the UAPI headers, the dependency on the toolchain libc can be dropped.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---
usr/include/Makefile | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/usr/include/Makefile b/usr/include/Makefile
index fdc79cffcc97..d352280b0e4a 100644
--- a/usr/include/Makefile
+++ b/usr/include/Makefile
@@ -138,14 +138,13 @@ endif
always-y := $(patsubst $(obj)/%.h,%.hdrtest, $(shell find $(obj) -name '*.h' 2>/dev/null))
target-no-libc = $(filter-out $(uses-libc), $*.h)
-target-can-compile = $(and $(filter-out $(no-header-test), $*.h), \
- $(or $(CONFIG_CC_CAN_LINK), $(target-no-libc)))
+target-can-compile = $(filter-out $(no-header-test), $*.h)
# Include the header twice to detect missing include guard.
quiet_cmd_hdrtest = HDRTEST $<
cmd_hdrtest = \
$(CC) $(c_flags) -fsyntax-only -Werror -x c /dev/null \
- $(if $(target-no-libc), -nostdinc, -I $(srctree)/usr/dummy-include) \
+ -nostdinc $(if $(target-no-libc), , -I $(srctree)/usr/dummy-include) \
$(if $(target-can-compile), -include $< -include $<); \
$(PERL) $(src)/headers_check.pl $(obj) $<; \
touch $@
--
2.53.0
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH 8/9] kbuild: uapi: simplify libc dependency logic
2026-02-27 6:37 [PATCH 0/9] kbuild: uapi: remove usage of toolchain headers Thomas Weißschuh
` (6 preceding siblings ...)
2026-02-27 6:38 ` [PATCH 7/9] kbuild: uapi: use custom stub headers instead of libc ones Thomas Weißschuh
@ 2026-02-27 6:38 ` Thomas Weißschuh
2026-02-27 6:38 ` [PATCH 9/9] kbuild: uapi: remove now unneeded guard headers Thomas Weißschuh
` (4 subsequent siblings)
12 siblings, 0 replies; 16+ messages in thread
From: Thomas Weißschuh @ 2026-02-27 6:38 UTC (permalink / raw)
To: Nathan Chancellor, Nicolas Schier, Brian Cain
Cc: linux-kbuild, linux-kernel, Arnd Bergmann, linux-hexagon,
Thomas Weißschuh
The only left user of the condition inverts it.
Invert the condition completely and simplify its user.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---
usr/include/Makefile | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/usr/include/Makefile b/usr/include/Makefile
index d352280b0e4a..845d06b63c2b 100644
--- a/usr/include/Makefile
+++ b/usr/include/Makefile
@@ -137,14 +137,14 @@ endif
always-y := $(patsubst $(obj)/%.h,%.hdrtest, $(shell find $(obj) -name '*.h' 2>/dev/null))
-target-no-libc = $(filter-out $(uses-libc), $*.h)
+target-libc = $(filter $(uses-libc), $*.h)
target-can-compile = $(filter-out $(no-header-test), $*.h)
# Include the header twice to detect missing include guard.
quiet_cmd_hdrtest = HDRTEST $<
cmd_hdrtest = \
$(CC) $(c_flags) -fsyntax-only -Werror -x c /dev/null \
- -nostdinc $(if $(target-no-libc), , -I $(srctree)/usr/dummy-include) \
+ -nostdinc $(if $(target-libc), -I $(srctree)/usr/dummy-include) \
$(if $(target-can-compile), -include $< -include $<); \
$(PERL) $(src)/headers_check.pl $(obj) $<; \
touch $@
--
2.53.0
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH 9/9] kbuild: uapi: remove now unneeded guard headers
2026-02-27 6:37 [PATCH 0/9] kbuild: uapi: remove usage of toolchain headers Thomas Weißschuh
` (7 preceding siblings ...)
2026-02-27 6:38 ` [PATCH 8/9] kbuild: uapi: simplify libc dependency logic Thomas Weißschuh
@ 2026-02-27 6:38 ` Thomas Weißschuh
2026-02-27 9:18 ` [PATCH 0/9] kbuild: uapi: remove usage of toolchain headers Arnd Bergmann
` (3 subsequent siblings)
12 siblings, 0 replies; 16+ messages in thread
From: Thomas Weißschuh @ 2026-02-27 6:38 UTC (permalink / raw)
To: Nathan Chancellor, Nicolas Schier, Brian Cain
Cc: linux-kbuild, linux-kernel, Arnd Bergmann, linux-hexagon,
Thomas Weißschuh
The test compilation does not allow usage of the toolchain headers
anymore, so these dummy headers are not needed anymore.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---
usr/dummy-include/stdbool.h | 7 -------
usr/dummy-include/stdlib.h | 7 -------
2 files changed, 14 deletions(-)
diff --git a/usr/dummy-include/stdbool.h b/usr/dummy-include/stdbool.h
deleted file mode 100644
index 54ff9e9c90ac..000000000000
--- a/usr/dummy-include/stdbool.h
+++ /dev/null
@@ -1,7 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only */
-#ifndef _STDBOOL_H
-#define _STDBOOL_H
-
-#error "Please do not include <stdbool.h> from exported headers"
-
-#endif /* _STDBOOL_H */
diff --git a/usr/dummy-include/stdlib.h b/usr/dummy-include/stdlib.h
deleted file mode 100644
index e8c21888e371..000000000000
--- a/usr/dummy-include/stdlib.h
+++ /dev/null
@@ -1,7 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only */
-#ifndef _STDLIB_H
-#define _STDLIB_H
-
-#error "Please do not include <stdlib.h> from exported headers"
-
-#endif /* _STDLIB_H */
--
2.53.0
^ permalink raw reply related [flat|nested] 16+ messages in thread* Re: [PATCH 0/9] kbuild: uapi: remove usage of toolchain headers
2026-02-27 6:37 [PATCH 0/9] kbuild: uapi: remove usage of toolchain headers Thomas Weißschuh
` (8 preceding siblings ...)
2026-02-27 6:38 ` [PATCH 9/9] kbuild: uapi: remove now unneeded guard headers Thomas Weißschuh
@ 2026-02-27 9:18 ` Arnd Bergmann
2026-02-27 9:38 ` Thomas Weißschuh
2026-03-05 9:41 ` Nicolas Schier
` (2 subsequent siblings)
12 siblings, 1 reply; 16+ messages in thread
From: Arnd Bergmann @ 2026-02-27 9:18 UTC (permalink / raw)
To: Thomas Weißschuh, Nathan Chancellor, Nicolas Schier,
Brian Cain
Cc: linux-kbuild, linux-kernel, linux-hexagon, Thomas Weißschuh
On Fri, Feb 27, 2026, at 07:37, Thomas Weißschuh wrote:
> Currently the test compilation of some UAPI headers requires a toolchain
> libc headers. Remove that dependency.
>
> Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Nice work!
Acked-by: Arnd Bergmann <arnd@arndb.de>
I had toyed around with a similar series, using a slightly different
approach of always using the in-kernel nolibc headers, and making
those compile across all architectures (using empty stubs for those
that are missing syscall entry functions).
I don't care much which way we do this as long as we can build test
the headers, but I wonder what your reason was for picking this
approach over the other.
Arnd
^ permalink raw reply [flat|nested] 16+ messages in thread* Re: [PATCH 0/9] kbuild: uapi: remove usage of toolchain headers
2026-02-27 9:18 ` [PATCH 0/9] kbuild: uapi: remove usage of toolchain headers Arnd Bergmann
@ 2026-02-27 9:38 ` Thomas Weißschuh
2026-02-27 10:04 ` Arnd Bergmann
0 siblings, 1 reply; 16+ messages in thread
From: Thomas Weißschuh @ 2026-02-27 9:38 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Thomas Weißschuh, Nathan Chancellor, Nicolas Schier,
Brian Cain, linux-kbuild, linux-kernel, linux-hexagon
On Fri, Feb 27, 2026 at 10:18:41AM +0100, Arnd Bergmann wrote:
> On Fri, Feb 27, 2026, at 07:37, Thomas Weißschuh wrote:
> > Currently the test compilation of some UAPI headers requires a toolchain
> > libc headers. Remove that dependency.
> >
> > Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
>
> Nice work!
>
> Acked-by: Arnd Bergmann <arnd@arndb.de>
>
> I had toyed around with a similar series, using a slightly different
> approach of always using the in-kernel nolibc headers, and making
> those compile across all architectures (using empty stubs for those
> that are missing syscall entry functions).
>
> I don't care much which way we do this as long as we can build test
> the headers, but I wonder what your reason was for picking this
> approach over the other.
My goal is to reduce the reliance of the UAPI headers on libc ones.
Hopefully we can remove libc usages from the UAPI headers and then also
drop the compatibility bits from the stub headers. If we use the full nolibc
the message to UAPI authors would not be clear and new dependencies may be
introduced again.
Thomas
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH 0/9] kbuild: uapi: remove usage of toolchain headers
2026-02-27 9:38 ` Thomas Weißschuh
@ 2026-02-27 10:04 ` Arnd Bergmann
0 siblings, 0 replies; 16+ messages in thread
From: Arnd Bergmann @ 2026-02-27 10:04 UTC (permalink / raw)
To: Thomas Weißschuh
Cc: Thomas Weißschuh, Nathan Chancellor, Nicolas Schier,
Brian Cain, linux-kbuild, linux-kernel, linux-hexagon
On Fri, Feb 27, 2026, at 10:38, Thomas Weißschuh wrote:
> On Fri, Feb 27, 2026 at 10:18:41AM +0100, Arnd Bergmann wrote:
>> On Fri, Feb 27, 2026, at 07:37, Thomas Weißschuh wrote:
>>
>> I had toyed around with a similar series, using a slightly different
>> approach of always using the in-kernel nolibc headers, and making
>> those compile across all architectures (using empty stubs for those
>> that are missing syscall entry functions).
>>
>> I don't care much which way we do this as long as we can build test
>> the headers, but I wonder what your reason was for picking this
>> approach over the other.
>
> My goal is to reduce the reliance of the UAPI headers on libc ones.
> Hopefully we can remove libc usages from the UAPI headers and then also
> drop the compatibility bits from the stub headers. If we use the full nolibc
> the message to UAPI authors would not be clear and new dependencies may be
> introduced again.
Good point, thanks for the clarification!
Arnd
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH 0/9] kbuild: uapi: remove usage of toolchain headers
2026-02-27 6:37 [PATCH 0/9] kbuild: uapi: remove usage of toolchain headers Thomas Weißschuh
` (9 preceding siblings ...)
2026-02-27 9:18 ` [PATCH 0/9] kbuild: uapi: remove usage of toolchain headers Arnd Bergmann
@ 2026-03-05 9:41 ` Nicolas Schier
2026-03-10 1:00 ` Nathan Chancellor
2026-03-12 12:08 ` Nicolas Schier
12 siblings, 0 replies; 16+ messages in thread
From: Nicolas Schier @ 2026-03-05 9:41 UTC (permalink / raw)
To: Thomas Weißschuh
Cc: Nathan Chancellor, Nicolas Schier, Brian Cain, linux-kbuild,
linux-kernel, Arnd Bergmann, linux-hexagon, Thomas Weißschuh
On Fri, 27 Feb 2026 07:37:58 +0100, Thomas Weißschuh <linux@weissschuh.net> wrote:
> Currently the test compilation of some UAPI headers requires a toolchain
> libc headers. Remove that dependency.
Thanks a lot for the highly appreciated clean up! Having -nostdinc in
UAPI header tests is good thing!
Kind regards,
Nicolas
Reviewed-by: Nicolas Schier <nsc@kernel.org>
Tested-by: Nicolas Schier <nsc@kernel.org>
--
Nicolas
^ permalink raw reply [flat|nested] 16+ messages in thread* Re: [PATCH 0/9] kbuild: uapi: remove usage of toolchain headers
2026-02-27 6:37 [PATCH 0/9] kbuild: uapi: remove usage of toolchain headers Thomas Weißschuh
` (10 preceding siblings ...)
2026-03-05 9:41 ` Nicolas Schier
@ 2026-03-10 1:00 ` Nathan Chancellor
2026-03-12 12:08 ` Nicolas Schier
12 siblings, 0 replies; 16+ messages in thread
From: Nathan Chancellor @ 2026-03-10 1:00 UTC (permalink / raw)
To: Thomas Weißschuh
Cc: Nicolas Schier, Brian Cain, linux-kbuild, linux-kernel,
Arnd Bergmann, linux-hexagon, Thomas Weißschuh
On Fri, Feb 27, 2026 at 07:37:58AM +0100, Thomas Weißschuh wrote:
> Currently the test compilation of some UAPI headers requires a toolchain
> libc headers. Remove that dependency.
>
> Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
> ---
> Thomas Weißschuh (9):
> hexagon: uapi: Fix structure alignment attribute
> kbuild: uapi: test linux/bpf_perf_event.h on powerpc
> kbuild: uapi: deduplicate linux/bpf_perf_event.h exclusions
> kbuild: uapi: completely exclude linux/bpf_perf_event.h on nios2
> kbuild: uapi: only use dummy-include for headers which use libc
> kbuild: uapi: provide stub includes for some libc headers
> kbuild: uapi: use custom stub headers instead of libc ones
> kbuild: uapi: simplify libc dependency logic
> kbuild: uapi: remove now unneeded guard headers
This is nice! For the series:
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Cheers,
Nathan
^ permalink raw reply [flat|nested] 16+ messages in thread* Re: [PATCH 0/9] kbuild: uapi: remove usage of toolchain headers
2026-02-27 6:37 [PATCH 0/9] kbuild: uapi: remove usage of toolchain headers Thomas Weißschuh
` (11 preceding siblings ...)
2026-03-10 1:00 ` Nathan Chancellor
@ 2026-03-12 12:08 ` Nicolas Schier
12 siblings, 0 replies; 16+ messages in thread
From: Nicolas Schier @ 2026-03-12 12:08 UTC (permalink / raw)
To: Nathan Chancellor, Brian Cain, Thomas Weißschuh
Cc: Nicolas Schier, linux-kbuild, linux-kernel, Arnd Bergmann,
linux-hexagon, Thomas Weißschuh
On Fri, 27 Feb 2026 07:37:58 +0100, Thomas Weißschuh wrote:
> Currently the test compilation of some UAPI headers requires a toolchain
> libc headers. Remove that dependency.
Applied to kbuild/kbuild-next.git (kbuild-next), thanks!
[1/9] hexagon: uapi: Fix structure alignment attribute
https://git.kernel.org/kbuild/c/47bca1cb
[2/9] kbuild: uapi: test linux/bpf_perf_event.h on powerpc
https://git.kernel.org/kbuild/c/a8c9d3cc
[3/9] kbuild: uapi: deduplicate linux/bpf_perf_event.h exclusions
https://git.kernel.org/kbuild/c/45bd8643
[4/9] kbuild: uapi: completely exclude linux/bpf_perf_event.h on nios2
https://git.kernel.org/kbuild/c/60a16bee
[5/9] kbuild: uapi: only use dummy-include for headers which use libc
https://git.kernel.org/kbuild/c/0ef1b7a6
[6/9] kbuild: uapi: provide stub includes for some libc headers
https://git.kernel.org/kbuild/c/aad94ba6
[7/9] kbuild: uapi: use custom stub headers instead of libc ones
https://git.kernel.org/kbuild/c/579f103f
[8/9] kbuild: uapi: simplify libc dependency logic
https://git.kernel.org/kbuild/c/510c7a57
[9/9] kbuild: uapi: remove now unneeded guard headers
https://git.kernel.org/kbuild/c/febb5c81
Please look out for regression or issue reports or other follow up
comments, as they may result in the patch/series getting dropped,
reverted or modified (e.g. trailers).
Best regards,
--
Nicolas
^ permalink raw reply [flat|nested] 16+ messages in thread