[PATCH v4 0/3] tools build: Fix arm64 unistd.h dependency

[PATCH v4 0/3] tools build: Fix arm64 unistd.h dependency

[Leo Yan]

The perf build includes arm64's unistd.h, but its dependent header
unistd_64.h is missing.

As suggested by Arnd in [1]:

  "I would suggest using the same method across all architectures:
   either we figure out how to use the generated headers on all of them
   (including x86, which uses yet another method), or we just stick with
   the old asm-generic/unistd.h copy and use that on arm64 as well."

A dynamic approach (e.g., make headers_install) may be explored later to
generate headers for tools, but that will need consensus from the tools
maintainers.  In the meantime, this series provides a quick fix by using
the asm-generic/unistd.h copy for arm64.

[1] https://lore.kernel.org/linux-arm-kernel/20251222173653.GF9788@e132581.arm.com/T/#m69a051aae5e53a65f9b10e1d13f67b3e92f4bbc7

Signed-off-by: Leo Yan <leo.yan@arm.com>
---
Changes in v4:
- Updated commit log in patch 01 to avoid confusion (James).
- Link to v3: https://lore.kernel.org/r/20251222-perf_fix_syscall_header-v3-0-eb4a8b9dfe66@arm.com

Changes in v3:
- Changed to include asm-generic/unistd.h copy (Arnd).
- Removed check due to divergence between the kernel and tools.
- Link to v2: https://lore.kernel.org/r/20251210-perf_fix_syscall_header-v2-0-b18b6016e0ea@arm.com

Changes in v2:
- Added a consistency check (Ian).
- Rebased on the latest perf-tools-next.
- Link to v1: https://lore.kernel.org/r/20251204-perf_fix_syscall_header-v1-0-b8e27f74ed6a@arm.com

---
Leo Yan (3):
      tools headers: Go back to include asm-generic/unistd.h for arm64
      Revert "perf tools: Fix arm64 build by generating unistd_64.h"
      tools headers: Don't check arm64's unistd.h

 tools/arch/arm64/include/uapi/asm/unistd.h | 24 +++++++++++++++++++++++-
 tools/lib/perf/Makefile                    | 14 ++------------
 tools/perf/Makefile.config                 |  1 -
 tools/perf/check-headers.sh                |  1 -
 4 files changed, 25 insertions(+), 15 deletions(-)
---
base-commit: cbd41c6d4c26c161a2b0e70ad411d3885ff13507
change-id: 20251203-perf_fix_syscall_header-e280fa931d44

Best regards,
-- 
Leo Yan <leo.yan@arm.com>

[PATCH v4 1/3] tools headers: Go back to include asm-generic/unistd.h for arm64

[Leo Yan]

The header unistd.h is included under Arm64's uAPI folder (see
tools/arch/arm64/include/uapi/asm/), but it does not include its
dependent header unistd_64.h.  The intention is for unistd_64.h to be
generated dynamically using scripts/Makefile.asm-headers.

However, this dynamic approach causes problems because the header is not
available early enough, even though it is widely included throughout
tools.  Using the perf build as an example:

 1) Feature detection: Perf first runs feature tests.

    The BPF feature program test-bpf.c includes unistd.h.  Since
    unistd_64.h has not been generated yet, the program fails to build,
    and the BPF feature ends up being disabled.

 2) libperf build:

    The libperf Makefile later generates unistd_64.h on the fly, so
    libperf itself builds successfully.

 3) Final perf build:

    Although the perf binary can build successfully using the generated
    header, we never get a chance to build BPF skeleton programs,
    because BPF support was already disabled earlier.

Restore to include asm-generic/unistd.h for fixing the issue.  This
aligns with most architectures (x86 is a special case that keeps
unistd_32.h/unistd_64.h for its particular syscall numbers) and ensures
the header is available from the start.

Fixes: 22f72088ffe6 ("tools headers: Update the syscall table with the kernel sources")
Signed-off-by: Leo Yan <leo.yan@arm.com>
---
 tools/arch/arm64/include/uapi/asm/unistd.h | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/tools/arch/arm64/include/uapi/asm/unistd.h b/tools/arch/arm64/include/uapi/asm/unistd.h
index df36f23876e863ff0a9e88473d5339f7ab69516d..9306726337fe005e3cf3e1ffd38dc6356191fa95 100644
--- a/tools/arch/arm64/include/uapi/asm/unistd.h
+++ b/tools/arch/arm64/include/uapi/asm/unistd.h
@@ -1,2 +1,24 @@
 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
-#include <asm/unistd_64.h>
+/*
+ * Copyright (C) 2012 ARM Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#define __ARCH_WANT_RENAMEAT
+#define __ARCH_WANT_NEW_STAT
+#define __ARCH_WANT_SET_GET_RLIMIT
+#define __ARCH_WANT_TIME32_SYSCALLS
+#define __ARCH_WANT_MEMFD_SECRET
+
+#include <asm-generic/unistd.h>

-- 
2.34.1

[PATCH v4 2/3] Revert "perf tools: Fix arm64 build by generating unistd_64.h"

[Leo Yan]

This reverts:

commit 8988c4b91945 ("perf tools: Fix in-source libperf build")
commit bfb713ea53c7 ("perf tools: Fix arm64 build by generating unistd_64.h")

Since we now have a static unistd_64.h for the arm64 build, there is no
need to generate unistd_64.h in libperf.  Revert all patches related to
generating unistd_64.h.

Signed-off-by: Leo Yan <leo.yan@arm.com>
---
 tools/lib/perf/Makefile    | 14 ++------------
 tools/perf/Makefile.config |  1 -
 2 files changed, 2 insertions(+), 13 deletions(-)

diff --git a/tools/lib/perf/Makefile b/tools/lib/perf/Makefile
index 7fbb50b74c00b3b99ac538821124e04bfbc6da6a..ffcfd777c45181960afc7505ef8f85d0b7ea7e8d 100644
--- a/tools/lib/perf/Makefile
+++ b/tools/lib/perf/Makefile
@@ -42,7 +42,6 @@ libdir_relative_SQ = $(subst ','\'',$(libdir_relative))
 TEST_ARGS := $(if $(V),-v)
 
 INCLUDES = \
--I$(OUTPUT)arch/$(SRCARCH)/include/generated/uapi \
 -I$(srctree)/tools/lib/perf/include \
 -I$(srctree)/tools/lib/ \
 -I$(srctree)/tools/include \
@@ -100,16 +99,7 @@ $(LIBAPI)-clean:
 	$(call QUIET_CLEAN, libapi)
 	$(Q)$(MAKE) -C $(LIB_DIR) O=$(OUTPUT) clean >/dev/null
 
-uapi-asm := $(OUTPUT)arch/$(SRCARCH)/include/generated/uapi/asm
-ifeq ($(SRCARCH),arm64)
-	syscall-y := $(uapi-asm)/unistd_64.h
-endif
-uapi-asm-generic:
-	$(if $(syscall-y),\
-		$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.asm-headers obj=$(uapi-asm) \
-		generic=include/uapi/asm-generic $(syscall-y),)
-
-$(LIBPERF_IN): uapi-asm-generic FORCE
+$(LIBPERF_IN): FORCE
 	$(Q)$(MAKE) $(build)=libperf
 
 $(LIBPERF_A): $(LIBPERF_IN)
@@ -130,7 +120,7 @@ all: fixdep
 clean: $(LIBAPI)-clean
 	$(call QUIET_CLEAN, libperf) $(RM) $(LIBPERF_A) \
                 *.o *~ *.a *.so *.so.$(VERSION) *.so.$(LIBPERF_VERSION) .*.d .*.cmd tests/*.o LIBPERF-CFLAGS $(LIBPERF_PC) \
-                $(TESTS_STATIC) $(TESTS_SHARED) $(syscall-y)
+                $(TESTS_STATIC) $(TESTS_SHARED)
 
 TESTS_IN = tests-in.o
 
diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index bd9f4804d56babeeefd0c02758bebf1ff0c040dd..c97ed1190ea097c41ca83f2ace06c008cd7f0ca9 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -64,7 +64,6 @@ include $(srctree)/tools/scripts/Makefile.arch
 $(call detected_var,SRCARCH)
 
 CFLAGS += -I$(OUTPUT)arch/$(SRCARCH)/include/generated
-CFLAGS += -I$(OUTPUT)libperf/arch/$(SRCARCH)/include/generated/uapi
 
 # Additional ARCH settings for ppc
 ifeq ($(SRCARCH),powerpc)

-- 
2.34.1

[PATCH v4 3/3] tools headers: Don't check arm64's unistd.h

[Leo Yan]

The arm64 unistd.h in tools now diverges from the kernel header.
Comparing the two headers is pointless, remove the check.

Signed-off-by: Leo Yan <leo.yan@arm.com>
---
 tools/perf/check-headers.sh | 1 -
 1 file changed, 1 deletion(-)

diff --git a/tools/perf/check-headers.sh b/tools/perf/check-headers.sh
index e0537f275da2f79ea9e05b91300aa1e2f996e9f1..da3aca87457fdc56c96d4184f2dee88dab026d98 100755
--- a/tools/perf/check-headers.sh
+++ b/tools/perf/check-headers.sh
@@ -54,7 +54,6 @@ declare -a FILES=(
   "arch/s390/include/uapi/asm/kvm.h"
   "arch/s390/include/uapi/asm/sie.h"
   "arch/arm64/include/uapi/asm/kvm.h"
-  "arch/arm64/include/uapi/asm/unistd.h"
   "arch/alpha/include/uapi/asm/errno.h"
   "arch/mips/include/asm/errno.h"
   "arch/mips/include/uapi/asm/errno.h"

-- 
2.34.1

Re: [PATCH v4 0/3] tools build: Fix arm64 unistd.h dependency

[James Clark]

On 08/01/2026 9:43 am, Leo Yan wrote:
> The perf build includes arm64's unistd.h, but its dependent header
> unistd_64.h is missing.
> 
> As suggested by Arnd in [1]:
> 
>    "I would suggest using the same method across all architectures:
>     either we figure out how to use the generated headers on all of them
>     (including x86, which uses yet another method), or we just stick with
>     the old asm-generic/unistd.h copy and use that on arm64 as well."
> 
> A dynamic approach (e.g., make headers_install) may be explored later to
> generate headers for tools, but that will need consensus from the tools
> maintainers.  In the meantime, this series provides a quick fix by using
> the asm-generic/unistd.h copy for arm64.
> 

BPF feature detection is fixed on Arm with this change. And the make 
headers_install idea sounds good for later.

Reviewed-by: James Clark <james.clark@linaro.org>

> [1] https://lore.kernel.org/linux-arm-kernel/20251222173653.GF9788@e132581.arm.com/T/#m69a051aae5e53a65f9b10e1d13f67b3e92f4bbc7
> 
> Signed-off-by: Leo Yan <leo.yan@arm.com>
> ---
> Changes in v4:
> - Updated commit log in patch 01 to avoid confusion (James).
> - Link to v3: https://lore.kernel.org/r/20251222-perf_fix_syscall_header-v3-0-eb4a8b9dfe66@arm.com
> 
> Changes in v3:
> - Changed to include asm-generic/unistd.h copy (Arnd).
> - Removed check due to divergence between the kernel and tools.
> - Link to v2: https://lore.kernel.org/r/20251210-perf_fix_syscall_header-v2-0-b18b6016e0ea@arm.com
> 
> Changes in v2:
> - Added a consistency check (Ian).
> - Rebased on the latest perf-tools-next.
> - Link to v1: https://lore.kernel.org/r/20251204-perf_fix_syscall_header-v1-0-b8e27f74ed6a@arm.com
> 
> ---
> Leo Yan (3):
>        tools headers: Go back to include asm-generic/unistd.h for arm64
>        Revert "perf tools: Fix arm64 build by generating unistd_64.h"
>        tools headers: Don't check arm64's unistd.h
> 
>   tools/arch/arm64/include/uapi/asm/unistd.h | 24 +++++++++++++++++++++++-
>   tools/lib/perf/Makefile                    | 14 ++------------
>   tools/perf/Makefile.config                 |  1 -
>   tools/perf/check-headers.sh                |  1 -
>   4 files changed, 25 insertions(+), 15 deletions(-)
> ---
> base-commit: cbd41c6d4c26c161a2b0e70ad411d3885ff13507
> change-id: 20251203-perf_fix_syscall_header-e280fa931d44
> 
> Best regards,