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* [PATCH bpf-next v9 0/8] Introduce arena library and runtime
@ 2026-04-26 19:02 Emil Tsalapatis
  2026-04-26 19:02 ` [PATCH bpf-next v9 1/8] selftests/bpf: Add ifdef guard for WRITE_ONCE macro in bpf_atomic.h Emil Tsalapatis
                   ` (3 more replies)
  0 siblings, 4 replies; 6+ messages in thread
From: Emil Tsalapatis @ 2026-04-26 19:02 UTC (permalink / raw)
  To: bpf
  Cc: ast, andrii, memxor, daniel, eddyz87, song, mattbobfrowski,
	Emil Tsalapatis

Add a new subdirectory to tools/testing/selftests/bpf called libarena,
along with programs useful for writing arena-based BPF code. This
patchset adds the following:

1) libarena, a subdirectory where arena BPF code that is generally useful
to BPF arena programs can be easily added and tested.

2) An ASAN runtime for BPF arena programs. BPF arenas allow for accessing
memory after it has been freed or if it is out of bounds, making it more
difficult to triage bugs combined to regular BPF. Use LLVM's recently added
support for address-space based sanitization to selectively sanitize just
the arena accesses.

3) A buddy memory allocator that can be reused by BPF programs to handle
memory allocation/deletion. The allocator uses the ASAN runtime to add
address sanitization if requested.

The patch includes testing for the new allocators and ASAN features that
can be built from the top directory using "make libarena_test" and
"make libarena_test_asan". The generated binaries reside in libarena/.
The patch also adds test-progs-based selftests to the codebase for the
libarena code, so the new tests are run by ./test_progs.

The patchset has the following stucture:

1-3: Create basic libarena scaffolding and refactor existing headers.

4-5: Add the ASAN runtime and associated scaffolding.

6-8: Add the new buddy memory allocator along with selftests.

Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com>

HISTORY
=======

v8->v9 (https://lore.kernel.org/bpf/20260421165037.4736-1-emil@etsalapatis.com)
- Added Matt's Acked-by for Patch 1
- Replaced open coded fls with __builtin based calculation (Matt)
- Add comment explaining the reasoning behind the zero variable (Matt)
- Remove the self-contained runner and present selftests as examples (Kumar).
  The reasoning is that including selftests with the library is not
  effective because the library will be sync'ed outside the tree
  infrequently, so it would be ineffective in catching issues before
  they land.
- Adjust syscall API for clarity and forward compatibility (Matt)
- Reset asan_validate state after failed check (Sashiko)
- Fix printf format specifier (Sashiko)
- Rename syscall to be generic arena_info (Matt)
- Namespace libarena headers by moving them to their own directory
- Rename selftest_helpers to libarena/userspace.h to reflect it is not
  just for selftests.

v7->v8 (https://lore.kernel.org/bpf/20260412174546.18684-1-emil@etsalapatis.com)
- Duplicate READ_ONCE/WRITE_ONCE instead of moving it to
  bpf_experimental.h to keep libarena self-contained (Kumar)
- Add libarena_asan test to test_progs and conditionally compile it if
  suppported (Kumar)
- Add stderr parsing for buddy tests when run under test_progs (Kumar)
- Move all arena-related headers into libarena and add its include/
  subdirectory in the standard include path (Kumar)
- Remove silent-by-default ASAN, add help message on test_libarena
  explaining that -v emits the messages (Kumar)
- Add run_prog_args as a libarena helper
- Add explanation on the use of __weak for the spinlock qnodes

v6->v7 (https://lore.kernel.org/bpf/20260412011857.3387-1-emil@etsalapatis.com)
- Modify patch 1 to allow operations between PTR_TO_ARENA src_reg
and dst_reg of any type. Adjust selftests accordingly (Alexei)
- Remove unnecessary include in patch 5 (Song)
- Removed unused definitions/assignments in patches 8/9, update patch
  descriptions

v5->v6 (https://lore.kernel.org/bpf/20260410163041.8063-1-emil@etsalapatis.com)
- Fix subreg_def management for SCALAR += PTR_TO_ARENA operations (AI)
- Add more selftests for the SCALAR += PTR_TO_ARENA patch (Sashiko)
- Adjust fls() operation to be in line with the kernel version (Sashiko)
- Address Sashiko selftests and debugging nits
- Add ASAN loadN and storeN _noabort variants and associated BTF anchor
- Remove unnecessary bit freeing of buddies during block splitting

v4->v5 (https://lore.kernel.org/bpf/20260407045730.13359-1-emil@etsalapatis.com)
Omitting various nits and fixups.
- Properly adjust subreg_def for scalar += ptr_to_arena calls (Sashiko)
- Remove extraneous definition from prog_tests/arena_spin_lock.c (Song)
- Trim extraneous comments from ASAN and buddy (Alexei)
- Remove asan_dummy call and replace with function pointer array (Alexei)
- Remove usersapi.h header and merge it into common.h (Alexei)
- Replace ASAN macros with function calls (Alexei)
- Embed buddy lock into the struct and move the buddy allocator to __arena_global
  (Alexei)
- Add commenting for buddy allocator constants (Alexei)
- Add default buddy allocator directly in common.bpf.c, so that the user does
  not need to define it.
- Expand test harnesses to dynamically find individual selftests. Now the
  selftests also reports each test individually (e.g., 5 entries for the
  buddy allocator instead of 1). This brings them to par with the rest of
  the test_progs.

v3->v4 (https://lore.kernel.org/bpf/20260403042720.18862-1-emil@etsalapatis.com)
- Add Acks by Song to patches 1-4.
- Expand the verifier's handling of scalar/arena operations to
  include all 3-operand operations in Patch 1 (Alexei)
- Add additional tests for arena/arena (allowed) and arena/pointer (not allowed)
operations in Patch 2
- Remove ASAN version of the library from default compilation since it requires
LLVM 22 and up (CI)
- Rework buddy allocator locking for clarity and add comments
- Fix From: email to be consistent with SOB
- Address (most) Sashiko comments

v2->v3 (https://lore.kernel.org/bpf/20260127181610.86376-1-emil@etsalapatis.com)
Nonexhaustive due to significant patch rework.
- Do not duplicate WRITE_ONCE macro (Mykyta, Kumar)
- Add SPDX headers (Alexei)
- Remove bump/stack allocators (Alexei)
- Integrate testing with test_progs (Kumar)
- Add short description of ASAN algorithm at the top of the file (Alexei)

v1->v2 (https://lore.kernel.org/bpf/20260122160131.2238331-1-etsal@meta.com/)

- Added missing format string argument (AI)
- Fix outdated selftests prog name check (AI)
- Fixed stack allocation check for segment creation (AI)
- Fix errors in non-ASAN bump allocator selftests (AI)
- Propagate error value from individual selftests in selftest.c
- Removed embedded metadata from bump allocator as it was needlessly
  complicating its behavior



Emil Tsalapatis (8):
  selftests/bpf: Add ifdef guard for WRITE_ONCE macro in bpf_atomic.h
  selftests/bpf: Add basic libarena scaffolding
  selftests/bpf: Move arena-related headers into libarena
  selftests/bpf: Add arena ASAN runtime to libarena
  selftests/bpf: Add ASAN support for libarena selftests
  selftests/bpf: Add buddy allocator for libarena
  selftests/bpf: Add selftests for libarena buddy allocator
  selftests/bpf: Reuse stderr parsing for libarena ASAN tests

 tools/testing/selftests/bpf/Makefile          |  53 +-
 tools/testing/selftests/bpf/bpf_arena_alloc.h |   2 +-
 tools/testing/selftests/bpf/bpf_arena_list.h  |   2 +-
 .../selftests/bpf/bpf_arena_strsearch.h       |   2 +-
 .../testing/selftests/bpf/bpf_experimental.h  |  84 +-
 tools/testing/selftests/bpf/default.profraw   | Bin 0 -> 160 bytes
 tools/testing/selftests/bpf/libarena/Makefile |  94 ++
 .../{ => libarena/include}/bpf_arena_common.h |   0
 .../include}/bpf_arena_spin_lock.h            |  11 +-
 .../bpf/{ => libarena/include}/bpf_atomic.h   |   4 +-
 .../bpf/libarena/include/bpf_may_goto.h       |  84 ++
 .../bpf/libarena/include/libarena/asan.h      | 103 ++
 .../bpf/libarena/include/libarena/buddy.h     |  92 ++
 .../bpf/libarena/include/libarena/common.h    |  94 ++
 .../bpf/libarena/include/libarena/userspace.h | 132 +++
 .../libarena/selftests/st_asan_buddy.bpf.c    | 258 +++++
 .../bpf/libarena/selftests/st_asan_common.h   |  52 +
 .../bpf/libarena/selftests/st_buddy.bpf.c     | 209 ++++
 .../libarena/selftests/test_progs_compat.h    |  15 +
 .../selftests/bpf/libarena/src/asan.bpf.c     | 553 +++++++++++
 .../selftests/bpf/libarena/src/buddy.bpf.c    | 903 ++++++++++++++++++
 .../selftests/bpf/libarena/src/common.bpf.c   |  52 +
 .../bpf/prog_tests/arena_spin_lock.c          |   7 -
 .../selftests/bpf/prog_tests/libarena.c       |  66 ++
 .../selftests/bpf/prog_tests/libarena_asan.c  |  93 ++
 .../selftests/bpf/progs/arena_atomics.c       |   2 +-
 .../selftests/bpf/progs/arena_spin_lock.c     |   2 +-
 .../bpf/progs/compute_live_registers.c        |   2 +-
 .../selftests/bpf/progs/lpm_trie_bench.c      |   2 +-
 tools/testing/selftests/bpf/progs/stream.c    |   2 +-
 .../selftests/bpf/progs/verifier_arena.c      |   2 +-
 .../bpf/progs/verifier_arena_globals1.c       |   2 +-
 .../bpf/progs/verifier_arena_globals2.c       |   2 +-
 .../bpf/progs/verifier_arena_large.c          |   2 +-
 .../selftests/bpf/progs/verifier_ldsx.c       |   2 +-
 tools/testing/selftests/bpf/test_loader.c     |  51 +-
 tools/testing/selftests/bpf/test_progs.h      |   2 +
 37 files changed, 2917 insertions(+), 121 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/default.profraw
 create mode 100644 tools/testing/selftests/bpf/libarena/Makefile
 rename tools/testing/selftests/bpf/{ => libarena/include}/bpf_arena_common.h (100%)
 rename tools/testing/selftests/bpf/{progs => libarena/include}/bpf_arena_spin_lock.h (98%)
 rename tools/testing/selftests/bpf/{ => libarena/include}/bpf_atomic.h (98%)
 create mode 100644 tools/testing/selftests/bpf/libarena/include/bpf_may_goto.h
 create mode 100644 tools/testing/selftests/bpf/libarena/include/libarena/asan.h
 create mode 100644 tools/testing/selftests/bpf/libarena/include/libarena/buddy.h
 create mode 100644 tools/testing/selftests/bpf/libarena/include/libarena/common.h
 create mode 100644 tools/testing/selftests/bpf/libarena/include/libarena/userspace.h
 create mode 100644 tools/testing/selftests/bpf/libarena/selftests/st_asan_buddy.bpf.c
 create mode 100644 tools/testing/selftests/bpf/libarena/selftests/st_asan_common.h
 create mode 100644 tools/testing/selftests/bpf/libarena/selftests/st_buddy.bpf.c
 create mode 100644 tools/testing/selftests/bpf/libarena/selftests/test_progs_compat.h
 create mode 100644 tools/testing/selftests/bpf/libarena/src/asan.bpf.c
 create mode 100644 tools/testing/selftests/bpf/libarena/src/buddy.bpf.c
 create mode 100644 tools/testing/selftests/bpf/libarena/src/common.bpf.c
 create mode 100644 tools/testing/selftests/bpf/prog_tests/libarena.c
 create mode 100644 tools/testing/selftests/bpf/prog_tests/libarena_asan.c

-- 
2.53.0


^ permalink raw reply	[flat|nested] 6+ messages in thread
* [PATCH bpf-next v9 1/8] selftests/bpf: Add ifdef guard for WRITE_ONCE macro in bpf_atomic.h
  2026-04-26 19:02 [PATCH bpf-next v9 0/8] Introduce arena library and runtime Emil Tsalapatis
@ 2026-04-26 19:02 ` Emil Tsalapatis
  2026-04-26 19:02 ` [PATCH bpf-next v9 2/8] selftests/bpf: Add basic libarena scaffolding Emil Tsalapatis
                   ` (2 subsequent siblings)
  3 siblings, 0 replies; 6+ messages in thread
From: Emil Tsalapatis @ 2026-04-26 19:02 UTC (permalink / raw)
  To: bpf
  Cc: ast, andrii, memxor, daniel, eddyz87, song, mattbobfrowski,
	Emil Tsalapatis, Matt Bobrowski

The WRITE_ONCE macro is identically defined both in bpf_atomic.h
and in bpf_arena_common.h. However, the bpf_atomic.h definition has no
ifdef guard. If bpf_atomic.h is included after bpf_arena.common.h,
compilation fails because of the duplicate definition.

Guard the definiton in bpf_atomic.h with and ifdef to let programs
include the two headers in any order. Duplicating the definition is
the simplest solution out of all the alternatives:

- Keeping one of the two existing definitions is not possible because
both BPF atomics and arena programs need the macro, and the two features
are independent. Using one should not require the header for the other.

- Factoring out the definition into a new header that only includes it
is more churn than just duplicating it.

- Factoring out the definition into bpf_experimental.h requires all
users of WRITE_ONCE to include the header. However, the arena library
introduced in subsequent commits must be self-contained, while
bpf_experimental.h is in the base selftests/bpf directory.

Both headers are moved to the arena library in a subsequent patch.

Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com>
Reviewed-by: Matt Bobrowski <mattbobrowski@google.com>
---
 tools/testing/selftests/bpf/bpf_atomic.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/testing/selftests/bpf/bpf_atomic.h b/tools/testing/selftests/bpf/bpf_atomic.h
index c550e5711967..d89a22d63c1c 100644
--- a/tools/testing/selftests/bpf/bpf_atomic.h
+++ b/tools/testing/selftests/bpf/bpf_atomic.h
@@ -42,7 +42,9 @@ extern bool CONFIG_X86_64 __kconfig __weak;
 
 #define READ_ONCE(x) (*(volatile typeof(x) *)&(x))
 
+#ifndef WRITE_ONCE
 #define WRITE_ONCE(x, val) ((*(volatile typeof(x) *)&(x)) = (val))
+#endif
 
 #define cmpxchg(p, old, new) __sync_val_compare_and_swap((p), old, new)
 
-- 
2.53.0


^ permalink raw reply related	[flat|nested] 6+ messages in thread
* [PATCH bpf-next v9 2/8] selftests/bpf: Add basic libarena scaffolding
  2026-04-26 19:02 [PATCH bpf-next v9 0/8] Introduce arena library and runtime Emil Tsalapatis
  2026-04-26 19:02 ` [PATCH bpf-next v9 1/8] selftests/bpf: Add ifdef guard for WRITE_ONCE macro in bpf_atomic.h Emil Tsalapatis
@ 2026-04-26 19:02 ` Emil Tsalapatis
  2026-04-26 19:02 ` [PATCH bpf-next v9 3/8] selftests/bpf: Move arena-related headers into libarena Emil Tsalapatis
  2026-04-26 19:05 ` [PATCH bpf-next v9 0/8] Introduce arena library and runtime Emil Tsalapatis
  3 siblings, 0 replies; 6+ messages in thread
From: Emil Tsalapatis @ 2026-04-26 19:02 UTC (permalink / raw)
  To: bpf
  Cc: ast, andrii, memxor, daniel, eddyz87, song, mattbobfrowski,
	Emil Tsalapatis

Add initial code and a Makefile for an arena-based BPF library. Modules
can be added just by including the source file in the library's src/
subdirectory. Future commits will introduce the library code itself.

The code includes workarounds that are removed in subsequent patches
that ensure bisectability.

Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com>
---
 tools/testing/selftests/bpf/Makefile          | 27 +++++
 tools/testing/selftests/bpf/libarena/Makefile | 69 +++++++++++++
 .../bpf/libarena/include/libarena/common.h    | 79 +++++++++++++++
 .../bpf/libarena/include/libarena/userspace.h | 99 +++++++++++++++++++
 .../selftests/bpf/libarena/src/common.bpf.c   | 29 ++++++
 5 files changed, 303 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/libarena/Makefile
 create mode 100644 tools/testing/selftests/bpf/libarena/include/libarena/common.h
 create mode 100644 tools/testing/selftests/bpf/libarena/include/libarena/userspace.h
 create mode 100644 tools/testing/selftests/bpf/libarena/src/common.bpf.c

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 6ef6872adbc3..5855064e7f9c 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -153,6 +153,7 @@ override define CLEAN
 	$(Q)$(RM) -r $(TEST_KMODS)
 	$(Q)$(RM) -r $(EXTRA_CLEAN)
 	$(Q)$(MAKE) -C test_kmods clean
+	$(Q)$(MAKE) -C libarena clean
 	$(Q)$(MAKE) docs-clean
 endef
 
@@ -525,6 +526,7 @@ LINKED_BPF_OBJS := $(foreach skel,$(LINKED_SKELS),$($(skel)-deps))
 LINKED_BPF_SRCS := $(patsubst %.bpf.o,%.c,$(LINKED_BPF_OBJS))
 
 HEADERS_FOR_BPF_OBJS := $(wildcard $(BPFDIR)/*.bpf.h)		\
+			$(wildcard $(CURDIR)/libarena/include/*.[ch])	\
 			$(addprefix $(BPFDIR)/,	bpf_core_read.h	\
 			                        bpf_endian.h	\
 						bpf_helpers.h	\
@@ -740,6 +742,29 @@ $(VERIFY_SIG_HDR): $(VERIFICATION_CERT)
 	 echo "};"; \
 	 echo "unsigned int test_progs_verification_cert_len = $$(wc -c < $<);") > $@
 
+LIBARENA_MAKE_ARGS = \
+		BPFTOOL="$(BPFTOOL)" \
+		INCLUDE_DIR="$(INCLUDE_DIR)" \
+		LIBBPF_INCLUDE="$(HOST_INCLUDE_DIR)" \
+		BPFOBJ="$(BPFOBJ)" \
+		LDLIBS="$(LDLIBS) -lzstd" \
+		CLANG="$(CLANG)" \
+		BPF_CFLAGS="$(BPF_CFLAGS) $(CLANG_CFLAGS)" \
+		BPF_TARGET_ENDIAN="$(BPF_TARGET_ENDIAN)" \
+		Q="$(Q)"
+
+LIBARENA_BPF_DEPS := $(wildcard libarena/Makefile		\
+				 libarena/include/*		\
+				 libarena/include/libarena/*	\
+				 libarena/src/*			\
+				 libarena/selftests/*		\
+				 libarena/*.bpf.o)
+
+LIBARENA_SKEL := libarena/libarena.skel.h
+
+$(LIBARENA_SKEL): $(INCLUDE_DIR)/vmlinux.h $(BPFOBJ) $(LIBARENA_BPF_DEPS)
+	+$(MAKE) -C libarena libarena.skel.h $(LIBARENA_MAKE_ARGS)
+
 # Define test_progs test runner.
 TRUNNER_TESTS_DIR := prog_tests
 TRUNNER_BPF_PROGS_DIR := progs
@@ -933,3 +958,5 @@ override define INSTALL_RULE
 		rsync -a $(OUTPUT)/$$DIR/*.bpf.o $(INSTALL_PATH)/$$DIR;\
 	done
 endef
+
+libarena: $(LIBARENA_SKEL)
diff --git a/tools/testing/selftests/bpf/libarena/Makefile b/tools/testing/selftests/bpf/libarena/Makefile
new file mode 100644
index 000000000000..e85b3ad96890
--- /dev/null
+++ b/tools/testing/selftests/bpf/libarena/Makefile
@@ -0,0 +1,69 @@
+# SPDX-License-Identifier: LGPL-2.1 OR BSD-2-Clause
+# Copyright (c) 2026 Meta Platforms, Inc. and affiliates.
+
+.PHONY: clean
+
+# Defaults for standalone builds
+
+CLANG ?= clang
+BPFTOOL ?= bpftool
+LDLIBS ?= -lbpf -lelf -lz -lrt -lpthread -lzstd
+
+ifeq ($(V),1)
+Q =
+msg =
+else
+Q ?= @
+msg = @printf '  %-8s%s %s%s\n' "$(1)" "$(if $(2), [$(2)])" "$(notdir $(3))" "$(if $(4), $(4))";
+endif
+
+IS_LITTLE_ENDIAN = $(shell $(CC) -dM -E - </dev/null | \
+			grep 'define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__')
+BPF_TARGET_ENDIAN ?= $(if $(IS_LITTLE_ENDIAN),--target=bpfel,--target=bpfeb)
+
+LIBARENA=$(abspath .)
+BPFDIR=$(abspath $(LIBARENA)/..)
+
+INCLUDE_DIR ?= $(BPFDIR)/tools/include
+LIBBPF_INCLUDE ?= $(INCLUDE_DIR)
+
+# Scan src/ and selftests/ to generate the final binaries
+LIBARENA_SOURCES = $(wildcard $(LIBARENA)/src/*.bpf.c) $(wildcard $(LIBARENA)/selftests/*.bpf.c)
+LIBARENA_OBJECTS = $(notdir $(LIBARENA_SOURCES:.bpf.c=.bpf.o))
+
+INCLUDES = -I$(LIBARENA)/include -I$(BPFDIR)
+ifneq ($(INCLUDE_DIR),)
+INCLUDES += -I$(INCLUDE_DIR)
+endif
+ifneq ($(LIBBPF_INCLUDE),)
+INCLUDES += -I$(LIBBPF_INCLUDE)
+endif
+
+# ENABLE_ATOMICS_TESTS required because we use arena spinlocks
+override BPF_CFLAGS += -DENABLE_ATOMICS_TESTS
+override BPF_CFLAGS += -O2 -g
+override BPF_CFLAGS += -Wno-incompatible-pointer-types-discards-qualifiers
+# Required for suppressing harmless vmlinux.h-related warnings.
+override BPF_CFLAGS += -Wno-missing-declarations
+override BPF_CFLAGS += $(INCLUDES)
+
+CFLAGS = -O2 -no-pie
+CFLAGS += $(INCLUDES)
+
+vpath %.bpf.c $(LIBARENA)/src $(LIBARENA)/selftests
+vpath %.c $(LIBARENA)/src $(LIBARENA)/selftests
+
+libarena.skel.h: libarena.bpf.o
+	$(call msg,GEN-SKEL,libarena,$@)
+	$(Q)$(BPFTOOL) gen skeleton $< name "libarena" > $@
+
+libarena.bpf.o: $(LIBARENA_OBJECTS)
+	$(call msg,GEN-OBJ,libarena,$@)
+	$(Q)$(BPFTOOL) gen object $@ $^
+
+%.bpf.o: %.bpf.c
+	$(call msg,CLNG-BPF,libarena,$@)
+	$(Q)$(CLANG) $(BPF_CFLAGS) $(BPF_TARGET_ENDIAN) -c $< -o $@
+
+clean:
+	$(Q)rm -f *.skel.h *.bpf.o
diff --git a/tools/testing/selftests/bpf/libarena/include/libarena/common.h b/tools/testing/selftests/bpf/libarena/include/libarena/common.h
new file mode 100644
index 000000000000..92b67b20ed15
--- /dev/null
+++ b/tools/testing/selftests/bpf/libarena/include/libarena/common.h
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: LGPL-2.1 OR BSD-2-Clause
+/* Copyright (c) 2026 Meta Platforms, Inc. and affiliates. */
+#pragma once
+
+#ifdef __BPF__
+
+#include <vmlinux.h>
+
+#include "../../bpf_arena_common.h"
+#include "../../progs/bpf_arena_spin_lock.h"
+
+#include <asm-generic/errno.h>
+
+#ifndef __BPF_FEATURE_ADDR_SPACE_CAST
+#error "Arena allocators require bpf_addr_space_cast feature"
+#endif
+
+#define arena_stdout(fmt, ...) bpf_stream_printk(1, (fmt), ##__VA_ARGS__)
+#define arena_stderr(fmt, ...) bpf_stream_printk(2, (fmt), ##__VA_ARGS__)
+
+#ifndef __maybe_unused
+#define __maybe_unused __attribute__((__unused__))
+#endif
+
+#define private(name) SEC(".data." #name) __hidden __attribute__((aligned(8)))
+
+#define ARENA_PAGES (1UL << (32 - __builtin_ffs(__PAGE_SIZE) + 1))
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARENA);
+	__uint(map_flags, BPF_F_MMAPABLE);
+	__uint(max_entries, ARENA_PAGES); /* number of pages */
+#if defined(__TARGET_ARCH_arm64) || defined(__aarch64__)
+	__ulong(map_extra, (1ull << 32)); /* start of mmap() region */
+#else
+	__ulong(map_extra, (1ull << 44)); /* start of mmap() region */
+#endif
+} arena __weak SEC(".maps");
+
+/*
+ * This is a variable used to aid verification. The may_goto directive
+ * permits open-coded for loops, but requires that the index variable is
+ * imprecise. To force the variable to be imprecise, initialize it with
+ * the opaque volatile variable 0 instead of the constant 0.
+ */
+extern const volatile u32 zero;
+
+int arena_fls(__u64 word);
+
+#else /* ! __BPF__ */
+
+#include <stdint.h>
+
+#define __arena
+
+typedef uint8_t u8;
+typedef uint16_t u16;
+typedef uint32_t u32;
+typedef uint64_t u64;
+typedef int8_t s8;
+typedef int16_t s16;
+typedef int32_t s32;
+typedef int64_t s64;
+
+/* Dummy "definition" for userspace. */
+#define arena_spinlock_t int
+
+#endif /* __BPF__ */
+
+struct arena_get_info_args {
+	void __arena *arena_base;
+};
+
+struct arena_alloc_reserve_args {
+	u64 nr_pages;
+};
+
+/* Reasonable default number of pages reserved by arena_alloc_reserve. */
+#define ARENA_RESERVE_PAGES_DFL (8)
diff --git a/tools/testing/selftests/bpf/libarena/include/libarena/userspace.h b/tools/testing/selftests/bpf/libarena/include/libarena/userspace.h
new file mode 100644
index 000000000000..0438a751d5fd
--- /dev/null
+++ b/tools/testing/selftests/bpf/libarena/include/libarena/userspace.h
@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: LGPL-2.1 OR BSD-2-Clause
+/* Copyright (c) 2026 Meta Platforms, Inc. and affiliates. */
+#pragma once
+
+#include <errno.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/mman.h>
+
+#include <bpf/libbpf.h>
+#include <bpf/bpf.h>
+
+static inline int libarena_run_prog(int prog_fd)
+{
+	LIBBPF_OPTS(bpf_test_run_opts, opts);
+	int ret;
+
+	ret = bpf_prog_test_run_opts(prog_fd, &opts);
+	if (ret)
+		return ret;
+
+	return opts.retval;
+}
+
+static inline bool libarena_is_test_prog(const char *name)
+{
+	return strstr(name, "test_") == name;
+}
+
+static inline int libarena_run_prog_args(int prog_fd, void *args, size_t argsize)
+{
+	LIBBPF_OPTS(bpf_test_run_opts, opts);
+	int ret;
+
+	opts.ctx_in = args;
+	opts.ctx_size_in = argsize;
+
+	ret = bpf_prog_test_run_opts(prog_fd, &opts);
+
+	return ret ?: opts.retval;
+}
+
+static inline int libarena_get_arena_base(int arena_get_info_fd,
+					  void **arena_base)
+{
+	LIBBPF_OPTS(bpf_test_run_opts, opts);
+	struct arena_get_info_args args = { .arena_base = NULL };
+	int ret;
+
+	opts.ctx_in = &args;
+	opts.ctx_size_in = sizeof(args);
+
+	ret = bpf_prog_test_run_opts(arena_get_info_fd, &opts);
+	if (ret)
+		return ret;
+	if (opts.retval)
+		return opts.retval;
+
+	*arena_base = args.arena_base;
+	return 0;
+}
+
+static inline int libarena_get_globals_pages(int arena_get_globals_fd,
+					     size_t arena_all_pages,
+					     u64 *globals_pages)
+{
+	size_t pgsize = sysconf(_SC_PAGESIZE);
+	void *arena_base;
+	ssize_t i;
+	u8 *vec;
+	int ret;
+
+	ret = libarena_get_arena_base(arena_get_globals_fd, &arena_base);
+	if (ret)
+		return ret;
+
+	if (!arena_base)
+		return -EINVAL;
+
+	vec = calloc(arena_all_pages, sizeof(*vec));
+	if (!vec)
+		return -ENOMEM;
+
+	if (mincore(arena_base, arena_all_pages * pgsize, vec) < 0) {
+		ret = -errno;
+		free(vec);
+		return ret;
+	}
+
+	*globals_pages = 0;
+	for (i = arena_all_pages - 1; i >= 0; i--) {
+		if (!(vec[i] & 0x1))
+			break;
+		*globals_pages += 1;
+	}
+
+	free(vec);
+	return 0;
+}
diff --git a/tools/testing/selftests/bpf/libarena/src/common.bpf.c b/tools/testing/selftests/bpf/libarena/src/common.bpf.c
new file mode 100644
index 000000000000..659ccead5624
--- /dev/null
+++ b/tools/testing/selftests/bpf/libarena/src/common.bpf.c
@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: LGPL-2.1 OR BSD-2-Clause
+/* Copyright (c) 2026 Meta Platforms, Inc. and affiliates. */
+#include <libarena/common.h>
+
+const volatile u32 zero = 0;
+
+int arena_fls(__u64 word)
+{
+	if (!word)
+		return 0;
+
+	return 64 - __builtin_clzll(word);
+}
+
+SEC("syscall")
+__weak int arena_get_info(struct arena_get_info_args *args)
+{
+	args->arena_base = arena_base(&arena);
+
+	return 0;
+}
+
+SEC("syscall")
+__weak int arena_alloc_reserve(struct arena_alloc_reserve_args *args)
+{
+	return bpf_arena_reserve_pages(&arena, NULL, args->nr_pages);
+}
+
+char _license[] SEC("license") = "GPL";
-- 
2.53.0


^ permalink raw reply related	[flat|nested] 6+ messages in thread
* [PATCH bpf-next v9 3/8] selftests/bpf: Move arena-related headers into libarena
  2026-04-26 19:02 [PATCH bpf-next v9 0/8] Introduce arena library and runtime Emil Tsalapatis
  2026-04-26 19:02 ` [PATCH bpf-next v9 1/8] selftests/bpf: Add ifdef guard for WRITE_ONCE macro in bpf_atomic.h Emil Tsalapatis
  2026-04-26 19:02 ` [PATCH bpf-next v9 2/8] selftests/bpf: Add basic libarena scaffolding Emil Tsalapatis
@ 2026-04-26 19:02 ` Emil Tsalapatis
  2026-04-26 19:05 ` [PATCH bpf-next v9 0/8] Introduce arena library and runtime Emil Tsalapatis
  3 siblings, 0 replies; 6+ messages in thread
From: Emil Tsalapatis @ 2026-04-26 19:02 UTC (permalink / raw)
  To: bpf
  Cc: ast, andrii, memxor, daniel, eddyz87, song, mattbobfrowski,
	Emil Tsalapatis

The BPF selftest headers include functionality that is
specific to arenas and is required by libarena. Keep libarena
self-contained by moving all functionality into its include/
directory. Also add libarena/include to the standard include
paths for the selftests to make the moved headers easy to
access by existing selftests.

Some functionality is required by libarena but not strictly
arena-related. We still move it to the libarena/include path,
which is an upgrade from directly accessing them from the
selftests/bpf directory using relative paths.

A new bpf_may_goto.h file is split off of bpf_experimental.h.
bpf_arena_spin_lock.h and bpf_arena_common.h are moved to
libarena/include. bpf_atomic.h is also moved to libarena
because it is necessary for arena spinlocks.

For bpf_arena_spin_lock.h, mark the spinlock state array as __weak
to define the spinlock state array in the header while also
being compatible with multi-compilation unit programs. While
we're at it, we remove unnecessary definitions from existing
test programs.

Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com>
---
 tools/testing/selftests/bpf/Makefile          |  4 +-
 tools/testing/selftests/bpf/bpf_arena_alloc.h |  2 +-
 tools/testing/selftests/bpf/bpf_arena_list.h  |  2 +-
 .../selftests/bpf/bpf_arena_strsearch.h       |  2 +-
 .../testing/selftests/bpf/bpf_experimental.h  | 84 +------------------
 .../{ => libarena/include}/bpf_arena_common.h |  0
 .../include}/bpf_arena_spin_lock.h            | 11 ++-
 .../bpf/{ => libarena/include}/bpf_atomic.h   |  2 +-
 .../bpf/libarena/include/bpf_may_goto.h       | 84 +++++++++++++++++++
 .../bpf/libarena/include/libarena/common.h    |  4 +-
 .../bpf/prog_tests/arena_spin_lock.c          |  7 --
 .../selftests/bpf/progs/arena_atomics.c       |  2 +-
 .../selftests/bpf/progs/arena_spin_lock.c     |  2 +-
 .../bpf/progs/compute_live_registers.c        |  2 +-
 .../selftests/bpf/progs/lpm_trie_bench.c      |  2 +-
 tools/testing/selftests/bpf/progs/stream.c    |  2 +-
 .../selftests/bpf/progs/verifier_arena.c      |  2 +-
 .../bpf/progs/verifier_arena_globals1.c       |  2 +-
 .../bpf/progs/verifier_arena_globals2.c       |  2 +-
 .../bpf/progs/verifier_arena_large.c          |  2 +-
 .../selftests/bpf/progs/verifier_ldsx.c       |  2 +-
 21 files changed, 112 insertions(+), 110 deletions(-)
 rename tools/testing/selftests/bpf/{ => libarena/include}/bpf_arena_common.h (100%)
 rename tools/testing/selftests/bpf/{progs => libarena/include}/bpf_arena_spin_lock.h (98%)
 rename tools/testing/selftests/bpf/{ => libarena/include}/bpf_atomic.h (99%)
 create mode 100644 tools/testing/selftests/bpf/libarena/include/bpf_may_goto.h

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 5855064e7f9c..13959c449893 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -56,7 +56,8 @@ CFLAGS += -g $(OPT_FLAGS) -rdynamic -std=gnu11				\
 	  -Wno-unused-but-set-variable					\
 	  $(GENFLAGS) $(SAN_CFLAGS) $(LIBELF_CFLAGS)			\
 	  -I$(CURDIR) -I$(INCLUDE_DIR) -I$(GENDIR) -I$(LIBDIR)		\
-	  -I$(TOOLSINCDIR) -I$(TOOLSARCHINCDIR) -I$(APIDIR) -I$(OUTPUT)
+	  -I$(TOOLSINCDIR) -I$(TOOLSARCHINCDIR) -I$(APIDIR) -I$(OUTPUT)	\
+	  -I$(CURDIR)/libarena/include
 LDFLAGS += $(SAN_LDFLAGS)
 LDLIBS += $(LIBELF_LIBS) -lz -lrt -lpthread
 
@@ -447,6 +448,7 @@ endif
 CLANG_SYS_INCLUDES = $(call get_sys_includes,$(CLANG),$(CLANG_TARGET_ARCH))
 BPF_CFLAGS = -g -Wall -Werror -D__TARGET_ARCH_$(SRCARCH) $(MENDIAN)	\
 	     -I$(INCLUDE_DIR) -I$(CURDIR) -I$(APIDIR)			\
+	     -I$(CURDIR)/libarena/include				\
 	     -I$(abspath $(OUTPUT)/../usr/include)			\
 	     -std=gnu11		 					\
 	     -fno-strict-aliasing 					\
diff --git a/tools/testing/selftests/bpf/bpf_arena_alloc.h b/tools/testing/selftests/bpf/bpf_arena_alloc.h
index c27678299e0c..cda147fd9d25 100644
--- a/tools/testing/selftests/bpf/bpf_arena_alloc.h
+++ b/tools/testing/selftests/bpf/bpf_arena_alloc.h
@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
 /* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */
 #pragma once
-#include "bpf_arena_common.h"
+#include <bpf_arena_common.h>
 
 #ifndef __round_mask
 #define __round_mask(x, y) ((__typeof__(x))((y)-1))
diff --git a/tools/testing/selftests/bpf/bpf_arena_list.h b/tools/testing/selftests/bpf/bpf_arena_list.h
index e16fa7d95fcf..1af2ffc27d9c 100644
--- a/tools/testing/selftests/bpf/bpf_arena_list.h
+++ b/tools/testing/selftests/bpf/bpf_arena_list.h
@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
 /* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */
 #pragma once
-#include "bpf_arena_common.h"
+#include <bpf_arena_common.h>
 
 struct arena_list_node;
 
diff --git a/tools/testing/selftests/bpf/bpf_arena_strsearch.h b/tools/testing/selftests/bpf/bpf_arena_strsearch.h
index c1b6eaa905bb..f0d575daef5a 100644
--- a/tools/testing/selftests/bpf/bpf_arena_strsearch.h
+++ b/tools/testing/selftests/bpf/bpf_arena_strsearch.h
@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
 /* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */
 #pragma once
-#include "bpf_arena_common.h"
+#include <bpf_arena_common.h>
 
 __noinline int bpf_arena_strlen(const char __arena *s __arg_arena)
 {
diff --git a/tools/testing/selftests/bpf/bpf_experimental.h b/tools/testing/selftests/bpf/bpf_experimental.h
index 2234bd6bc9d3..d1db355e872b 100644
--- a/tools/testing/selftests/bpf/bpf_experimental.h
+++ b/tools/testing/selftests/bpf/bpf_experimental.h
@@ -5,6 +5,7 @@
 #include <bpf/bpf_tracing.h>
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_core_read.h>
+#include <bpf_may_goto.h>
 
 #define __contains(name, node) __attribute__((btf_decl_tag("contains:" #name ":" #node)))
 
@@ -204,89 +205,6 @@ l_true:												\
        })
 #endif
 
-/*
- * Note that cond_break can only be portably used in the body of a breakable
- * construct, whereas can_loop can be used anywhere.
- */
-#ifdef __BPF_FEATURE_MAY_GOTO
-#define can_loop					\
-	({ __label__ l_break, l_continue;		\
-	bool ret = true;				\
-	asm volatile goto("may_goto %l[l_break]"	\
-		      :::: l_break);			\
-	goto l_continue;				\
-	l_break: ret = false;				\
-	l_continue:;					\
-	ret;						\
-	})
-
-#define __cond_break(expr)				\
-	({ __label__ l_break, l_continue;		\
-	asm volatile goto("may_goto %l[l_break]"	\
-		      :::: l_break);			\
-	goto l_continue;				\
-	l_break: expr;					\
-	l_continue:;					\
-	})
-#else
-#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
-#define can_loop					\
-	({ __label__ l_break, l_continue;		\
-	bool ret = true;				\
-	asm volatile goto("1:.byte 0xe5;		\
-		      .byte 0;				\
-		      .long ((%l[l_break] - 1b - 8) / 8) & 0xffff;	\
-		      .short 0"				\
-		      :::: l_break);			\
-	goto l_continue;				\
-	l_break: ret = false;				\
-	l_continue:;					\
-	ret;						\
-	})
-
-#define __cond_break(expr)				\
-	({ __label__ l_break, l_continue;		\
-	asm volatile goto("1:.byte 0xe5;		\
-		      .byte 0;				\
-		      .long ((%l[l_break] - 1b - 8) / 8) & 0xffff;	\
-		      .short 0"				\
-		      :::: l_break);			\
-	goto l_continue;				\
-	l_break: expr;					\
-	l_continue:;					\
-	})
-#else
-#define can_loop					\
-	({ __label__ l_break, l_continue;		\
-	bool ret = true;				\
-	asm volatile goto("1:.byte 0xe5;		\
-		      .byte 0;				\
-		      .long (((%l[l_break] - 1b - 8) / 8) & 0xffff) << 16;	\
-		      .short 0"				\
-		      :::: l_break);			\
-	goto l_continue;				\
-	l_break: ret = false;				\
-	l_continue:;					\
-	ret;						\
-	})
-
-#define __cond_break(expr)				\
-	({ __label__ l_break, l_continue;		\
-	asm volatile goto("1:.byte 0xe5;		\
-		      .byte 0;				\
-		      .long (((%l[l_break] - 1b - 8) / 8) & 0xffff) << 16;	\
-		      .short 0"				\
-		      :::: l_break);			\
-	goto l_continue;				\
-	l_break: expr;					\
-	l_continue:;					\
-	})
-#endif
-#endif
-
-#define cond_break __cond_break(break)
-#define cond_break_label(label) __cond_break(goto label)
-
 #ifndef bpf_nop_mov
 #define bpf_nop_mov(var) \
 	asm volatile("%[reg]=%[reg]"::[reg]"r"((short)var))
diff --git a/tools/testing/selftests/bpf/bpf_arena_common.h b/tools/testing/selftests/bpf/libarena/include/bpf_arena_common.h
similarity index 100%
rename from tools/testing/selftests/bpf/bpf_arena_common.h
rename to tools/testing/selftests/bpf/libarena/include/bpf_arena_common.h
diff --git a/tools/testing/selftests/bpf/progs/bpf_arena_spin_lock.h b/tools/testing/selftests/bpf/libarena/include/bpf_arena_spin_lock.h
similarity index 98%
rename from tools/testing/selftests/bpf/progs/bpf_arena_spin_lock.h
rename to tools/testing/selftests/bpf/libarena/include/bpf_arena_spin_lock.h
index f90531cf3ee5..164638690a4d 100644
--- a/tools/testing/selftests/bpf/progs/bpf_arena_spin_lock.h
+++ b/tools/testing/selftests/bpf/libarena/include/bpf_arena_spin_lock.h
@@ -5,7 +5,7 @@
 
 #include <vmlinux.h>
 #include <bpf/bpf_helpers.h>
-#include "bpf_atomic.h"
+#include <bpf_atomic.h>
 
 #define arch_mcs_spin_lock_contended_label(l, label) smp_cond_load_acquire_label(l, VAL, label)
 #define arch_mcs_spin_unlock_contended(l) smp_store_release((l), 1)
@@ -107,7 +107,12 @@ struct arena_qnode {
 #define _Q_LOCKED_VAL		(1U << _Q_LOCKED_OFFSET)
 #define _Q_PENDING_VAL		(1U << _Q_PENDING_OFFSET)
 
-struct arena_qnode __arena qnodes[_Q_MAX_CPUS][_Q_MAX_NODES];
+/*
+ * The qnodes are marked __weak so we can define them in the header
+ * while still ensuring all compilation units use the same struct
+ * instance.
+ */
+struct arena_qnode __weak __arena __hidden qnodes[_Q_MAX_CPUS][_Q_MAX_NODES];
 
 static inline u32 encode_tail(int cpu, int idx)
 {
@@ -240,7 +245,7 @@ static __always_inline int arena_spin_trylock(arena_spinlock_t __arena *lock)
 	return likely(atomic_try_cmpxchg_acquire(&lock->val, &val, _Q_LOCKED_VAL));
 }
 
-__noinline
+__noinline __weak
 int arena_spin_lock_slowpath(arena_spinlock_t __arena __arg_arena *lock, u32 val)
 {
 	struct arena_mcs_spinlock __arena *prev, *next, *node0, *node;
diff --git a/tools/testing/selftests/bpf/bpf_atomic.h b/tools/testing/selftests/bpf/libarena/include/bpf_atomic.h
similarity index 99%
rename from tools/testing/selftests/bpf/bpf_atomic.h
rename to tools/testing/selftests/bpf/libarena/include/bpf_atomic.h
index d89a22d63c1c..b7b230431929 100644
--- a/tools/testing/selftests/bpf/bpf_atomic.h
+++ b/tools/testing/selftests/bpf/libarena/include/bpf_atomic.h
@@ -5,7 +5,7 @@
 
 #include <vmlinux.h>
 #include <bpf/bpf_helpers.h>
-#include "bpf_experimental.h"
+#include <bpf_may_goto.h>
 
 extern bool CONFIG_X86_64 __kconfig __weak;
 
diff --git a/tools/testing/selftests/bpf/libarena/include/bpf_may_goto.h b/tools/testing/selftests/bpf/libarena/include/bpf_may_goto.h
new file mode 100644
index 000000000000..9ba90689d6ba
--- /dev/null
+++ b/tools/testing/selftests/bpf/libarena/include/bpf_may_goto.h
@@ -0,0 +1,84 @@
+#pragma once
+
+/*
+ * Note that cond_break can only be portably used in the body of a breakable
+ * construct, whereas can_loop can be used anywhere.
+ */
+#ifdef __BPF_FEATURE_MAY_GOTO
+#define can_loop					\
+	({ __label__ l_break, l_continue;		\
+	bool ret = true;				\
+	asm volatile goto("may_goto %l[l_break]"	\
+		      :::: l_break);			\
+	goto l_continue;				\
+	l_break: ret = false;				\
+	l_continue:;					\
+	ret;						\
+	})
+
+#define __cond_break(expr)				\
+	({ __label__ l_break, l_continue;		\
+	asm volatile goto("may_goto %l[l_break]"	\
+		      :::: l_break);			\
+	goto l_continue;				\
+	l_break: expr;					\
+	l_continue:;					\
+	})
+#else
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+#define can_loop					\
+	({ __label__ l_break, l_continue;		\
+	bool ret = true;				\
+	asm volatile goto("1:.byte 0xe5;		\
+		      .byte 0;				\
+		      .long ((%l[l_break] - 1b - 8) / 8) & 0xffff;	\
+		      .short 0"				\
+		      :::: l_break);			\
+	goto l_continue;				\
+	l_break: ret = false;				\
+	l_continue:;					\
+	ret;						\
+	})
+
+#define __cond_break(expr)				\
+	({ __label__ l_break, l_continue;		\
+	asm volatile goto("1:.byte 0xe5;		\
+		      .byte 0;				\
+		      .long ((%l[l_break] - 1b - 8) / 8) & 0xffff;	\
+		      .short 0"				\
+		      :::: l_break);			\
+	goto l_continue;				\
+	l_break: expr;					\
+	l_continue:;					\
+	})
+#else
+#define can_loop					\
+	({ __label__ l_break, l_continue;		\
+	bool ret = true;				\
+	asm volatile goto("1:.byte 0xe5;		\
+		      .byte 0;				\
+		      .long (((%l[l_break] - 1b - 8) / 8) & 0xffff) << 16;	\
+		      .short 0"				\
+		      :::: l_break);			\
+	goto l_continue;				\
+	l_break: ret = false;				\
+	l_continue:;					\
+	ret;						\
+	})
+
+#define __cond_break(expr)				\
+	({ __label__ l_break, l_continue;		\
+	asm volatile goto("1:.byte 0xe5;		\
+		      .byte 0;				\
+		      .long (((%l[l_break] - 1b - 8) / 8) & 0xffff) << 16;	\
+		      .short 0"				\
+		      :::: l_break);			\
+	goto l_continue;				\
+	l_break: expr;					\
+	l_continue:;					\
+	})
+#endif
+#endif
+
+#define cond_break __cond_break(break)
+#define cond_break_label(label) __cond_break(goto label)
diff --git a/tools/testing/selftests/bpf/libarena/include/libarena/common.h b/tools/testing/selftests/bpf/libarena/include/libarena/common.h
index 92b67b20ed15..d088f3e75798 100644
--- a/tools/testing/selftests/bpf/libarena/include/libarena/common.h
+++ b/tools/testing/selftests/bpf/libarena/include/libarena/common.h
@@ -6,8 +6,8 @@
 
 #include <vmlinux.h>
 
-#include "../../bpf_arena_common.h"
-#include "../../progs/bpf_arena_spin_lock.h"
+#include <bpf_arena_common.h>
+#include <bpf_arena_spin_lock.h>
 
 #include <asm-generic/errno.h>
 
diff --git a/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c b/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c
index 693fd86fbde6..acb9d53b5973 100644
--- a/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c
+++ b/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c
@@ -5,13 +5,6 @@
 #include <sys/sysinfo.h>
 
 struct __qspinlock { int val; };
-typedef struct __qspinlock arena_spinlock_t;
-
-struct arena_qnode {
-	unsigned long next;
-	int count;
-	int locked;
-};
 
 #include "arena_spin_lock.skel.h"
 
diff --git a/tools/testing/selftests/bpf/progs/arena_atomics.c b/tools/testing/selftests/bpf/progs/arena_atomics.c
index d1841aac94a2..2e7751a85399 100644
--- a/tools/testing/selftests/bpf/progs/arena_atomics.c
+++ b/tools/testing/selftests/bpf/progs/arena_atomics.c
@@ -5,7 +5,7 @@
 #include <bpf/bpf_tracing.h>
 #include <stdbool.h>
 #include <stdatomic.h>
-#include "bpf_arena_common.h"
+#include <bpf_arena_common.h>
 #include "../../../include/linux/filter.h"
 #include "bpf_misc.h"
 
diff --git a/tools/testing/selftests/bpf/progs/arena_spin_lock.c b/tools/testing/selftests/bpf/progs/arena_spin_lock.c
index 086b57a426cf..7236d92d382f 100644
--- a/tools/testing/selftests/bpf/progs/arena_spin_lock.c
+++ b/tools/testing/selftests/bpf/progs/arena_spin_lock.c
@@ -4,7 +4,7 @@
 #include <bpf/bpf_tracing.h>
 #include <bpf/bpf_helpers.h>
 #include "bpf_misc.h"
-#include "bpf_arena_spin_lock.h"
+#include <bpf_arena_spin_lock.h>
 
 struct {
 	__uint(type, BPF_MAP_TYPE_ARENA);
diff --git a/tools/testing/selftests/bpf/progs/compute_live_registers.c b/tools/testing/selftests/bpf/progs/compute_live_registers.c
index f05e120f3450..d055fc7b3b95 100644
--- a/tools/testing/selftests/bpf/progs/compute_live_registers.c
+++ b/tools/testing/selftests/bpf/progs/compute_live_registers.c
@@ -3,7 +3,7 @@
 #include <linux/bpf.h>
 #include <bpf/bpf_helpers.h>
 #include "../../../include/linux/filter.h"
-#include "bpf_arena_common.h"
+#include <bpf_arena_common.h>
 #include "bpf_misc.h"
 
 struct {
diff --git a/tools/testing/selftests/bpf/progs/lpm_trie_bench.c b/tools/testing/selftests/bpf/progs/lpm_trie_bench.c
index a0e6ebd5507a..2831cf4445e8 100644
--- a/tools/testing/selftests/bpf/progs/lpm_trie_bench.c
+++ b/tools/testing/selftests/bpf/progs/lpm_trie_bench.c
@@ -7,7 +7,7 @@
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_core_read.h>
 #include "bpf_misc.h"
-#include "bpf_atomic.h"
+#include <bpf_atomic.h>
 #include "progs/lpm_trie.h"
 
 #define BPF_OBJ_NAME_LEN 16U
diff --git a/tools/testing/selftests/bpf/progs/stream.c b/tools/testing/selftests/bpf/progs/stream.c
index 6f999ba951a3..92ba1d72e0ec 100644
--- a/tools/testing/selftests/bpf/progs/stream.c
+++ b/tools/testing/selftests/bpf/progs/stream.c
@@ -5,7 +5,7 @@
 #include <bpf/bpf_helpers.h>
 #include "bpf_misc.h"
 #include "bpf_experimental.h"
-#include "bpf_arena_common.h"
+#include <bpf_arena_common.h>
 
 struct arr_elem {
 	struct bpf_res_spin_lock lock;
diff --git a/tools/testing/selftests/bpf/progs/verifier_arena.c b/tools/testing/selftests/bpf/progs/verifier_arena.c
index 62e282f4448a..89d72c8d756a 100644
--- a/tools/testing/selftests/bpf/progs/verifier_arena.c
+++ b/tools/testing/selftests/bpf/progs/verifier_arena.c
@@ -8,7 +8,7 @@
 #include <bpf/bpf_tracing.h>
 #include "bpf_misc.h"
 #include "bpf_experimental.h"
-#include "bpf_arena_common.h"
+#include <bpf_arena_common.h>
 
 #define private(name) SEC(".bss." #name) __hidden __attribute__((aligned(8)))
 
diff --git a/tools/testing/selftests/bpf/progs/verifier_arena_globals1.c b/tools/testing/selftests/bpf/progs/verifier_arena_globals1.c
index 83182ddbfb95..45d364b0bc85 100644
--- a/tools/testing/selftests/bpf/progs/verifier_arena_globals1.c
+++ b/tools/testing/selftests/bpf/progs/verifier_arena_globals1.c
@@ -6,7 +6,7 @@
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_tracing.h>
 #include "bpf_experimental.h"
-#include "bpf_arena_common.h"
+#include <bpf_arena_common.h>
 #include "bpf_misc.h"
 
 #define ARENA_PAGES (1UL<< (32 - __builtin_ffs(__PAGE_SIZE) + 1))
diff --git a/tools/testing/selftests/bpf/progs/verifier_arena_globals2.c b/tools/testing/selftests/bpf/progs/verifier_arena_globals2.c
index e6bd7b61f9f1..b51594dbc005 100644
--- a/tools/testing/selftests/bpf/progs/verifier_arena_globals2.c
+++ b/tools/testing/selftests/bpf/progs/verifier_arena_globals2.c
@@ -7,7 +7,7 @@
 #include <bpf/bpf_tracing.h>
 #include "bpf_misc.h"
 #include "bpf_experimental.h"
-#include "bpf_arena_common.h"
+#include <bpf_arena_common.h>
 
 #define ARENA_PAGES (32)
 
diff --git a/tools/testing/selftests/bpf/progs/verifier_arena_large.c b/tools/testing/selftests/bpf/progs/verifier_arena_large.c
index 5f7e7afee169..6ab8730d4878 100644
--- a/tools/testing/selftests/bpf/progs/verifier_arena_large.c
+++ b/tools/testing/selftests/bpf/progs/verifier_arena_large.c
@@ -7,7 +7,7 @@
 #include <bpf/bpf_tracing.h>
 #include "bpf_misc.h"
 #include "bpf_experimental.h"
-#include "bpf_arena_common.h"
+#include <bpf_arena_common.h>
 
 #define ARENA_SIZE (1ull << 32)
 
diff --git a/tools/testing/selftests/bpf/progs/verifier_ldsx.c b/tools/testing/selftests/bpf/progs/verifier_ldsx.c
index c8494b682c31..1026524a1983 100644
--- a/tools/testing/selftests/bpf/progs/verifier_ldsx.c
+++ b/tools/testing/selftests/bpf/progs/verifier_ldsx.c
@@ -3,7 +3,7 @@
 #include <linux/bpf.h>
 #include <bpf/bpf_helpers.h>
 #include "bpf_misc.h"
-#include "bpf_arena_common.h"
+#include <bpf_arena_common.h>
 
 #if (defined(__TARGET_ARCH_arm64) || defined(__TARGET_ARCH_x86) || \
 	(defined(__TARGET_ARCH_riscv) && __riscv_xlen == 64) || \
-- 
2.53.0


^ permalink raw reply related	[flat|nested] 6+ messages in thread
* [PATCH bpf-next v9 1/8] selftests/bpf: Add ifdef guard for WRITE_ONCE macro in bpf_atomic.h
  2026-04-26 19:03 Emil Tsalapatis
@ 2026-04-26 19:03 ` Emil Tsalapatis
  0 siblings, 0 replies; 6+ messages in thread
From: Emil Tsalapatis @ 2026-04-26 19:03 UTC (permalink / raw)
  To: bpf
  Cc: ast, andrii, memxor, daniel, eddyz87, song, mattbobrowski,
	Emil Tsalapatis

The WRITE_ONCE macro is identically defined both in bpf_atomic.h
and in bpf_arena_common.h. However, the bpf_atomic.h definition has no
ifdef guard. If bpf_atomic.h is included after bpf_arena.common.h,
compilation fails because of the duplicate definition.

Guard the definiton in bpf_atomic.h with and ifdef to let programs
include the two headers in any order. Duplicating the definition is
the simplest solution out of all the alternatives:

- Keeping one of the two existing definitions is not possible because
both BPF atomics and arena programs need the macro, and the two features
are independent. Using one should not require the header for the other.

- Factoring out the definition into a new header that only includes it
is more churn than just duplicating it.

- Factoring out the definition into bpf_experimental.h requires all
users of WRITE_ONCE to include the header. However, the arena library
introduced in subsequent commits must be self-contained, while
bpf_experimental.h is in the base selftests/bpf directory.

Both headers are moved to the arena library in a subsequent patch.

Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com>
Reviewed-by: Matt Bobrowski <mattbobrowski@google.com>
---
 tools/testing/selftests/bpf/bpf_atomic.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/testing/selftests/bpf/bpf_atomic.h b/tools/testing/selftests/bpf/bpf_atomic.h
index c550e5711967..d89a22d63c1c 100644
--- a/tools/testing/selftests/bpf/bpf_atomic.h
+++ b/tools/testing/selftests/bpf/bpf_atomic.h
@@ -42,7 +42,9 @@ extern bool CONFIG_X86_64 __kconfig __weak;
 
 #define READ_ONCE(x) (*(volatile typeof(x) *)&(x))
 
+#ifndef WRITE_ONCE
 #define WRITE_ONCE(x, val) ((*(volatile typeof(x) *)&(x)) = (val))
+#endif
 
 #define cmpxchg(p, old, new) __sync_val_compare_and_swap((p), old, new)
 
-- 
2.53.0


^ permalink raw reply related	[flat|nested] 6+ messages in thread
* Re: [PATCH bpf-next v9 0/8] Introduce arena library and runtime
  2026-04-26 19:02 [PATCH bpf-next v9 0/8] Introduce arena library and runtime Emil Tsalapatis
                   ` (2 preceding siblings ...)
  2026-04-26 19:02 ` [PATCH bpf-next v9 3/8] selftests/bpf: Move arena-related headers into libarena Emil Tsalapatis
@ 2026-04-26 19:05 ` Emil Tsalapatis
  3 siblings, 0 replies; 6+ messages in thread
From: Emil Tsalapatis @ 2026-04-26 19:05 UTC (permalink / raw)
  To: Emil Tsalapatis, bpf
  Cc: ast, andrii, memxor, daniel, eddyz87, song, mattbobfrowski

I typo'ed Matt's email in the CC list, resent after fixing - please disregard this one.

^ permalink raw reply	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2026-04-26 19:05 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2026-04-26 19:02 [PATCH bpf-next v9 0/8] Introduce arena library and runtime Emil Tsalapatis
2026-04-26 19:02 ` [PATCH bpf-next v9 1/8] selftests/bpf: Add ifdef guard for WRITE_ONCE macro in bpf_atomic.h Emil Tsalapatis
2026-04-26 19:02 ` [PATCH bpf-next v9 2/8] selftests/bpf: Add basic libarena scaffolding Emil Tsalapatis
2026-04-26 19:02 ` [PATCH bpf-next v9 3/8] selftests/bpf: Move arena-related headers into libarena Emil Tsalapatis
2026-04-26 19:05 ` [PATCH bpf-next v9 0/8] Introduce arena library and runtime Emil Tsalapatis
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2026-04-26 19:03 Emil Tsalapatis
2026-04-26 19:03 ` [PATCH bpf-next v9 1/8] selftests/bpf: Add ifdef guard for WRITE_ONCE macro in bpf_atomic.h Emil Tsalapatis

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