From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 4 Sep 2026 10:43:19 +0200 Subject: selftests/bpf: Reject graph kptr use after RCU unlock Add a sleepable verifier test that loads a graph-node local kptr in an explicit RCU read-side critical section, then passes its node to bpf_rbtree_remove() after the section ends. Before the verifier fix, the stale NON_OWN_REF flag makes the node look like a live borrowed reference and the program is accepted. After the fix, the pointer is demoted without NON_OWN_REF and the graph kfunc argument is rejected. Also exercise a graph kptr loaded while a spin lock provides implicit RCU protection. The pointer must be invalidated when the lock is released, which guards the required ordering between non-owning-reference invalidation and RCU demotion. Update the existing fault-protected load test state description. The post-unlock pointer no longer carries NON_OWN_REF, but remains readable because the load is rewritten to use BPF_PROBE_MEM. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- arch/hexagon/Makefile | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) create mode 100644 arch/hexagon/Makefile (limited to 'arch/hexagon/Makefile') diff --git a/arch/hexagon/Makefile b/arch/hexagon/Makefile new file mode 100644 index 000000000..ff172cbe5 --- /dev/null +++ b/arch/hexagon/Makefile @@ -0,0 +1,40 @@ +# SPDX-License-Identifier: GPL-2.0 +# Makefile for the Hexagon arch + +KBUILD_DEFCONFIG = comet_defconfig + +# Do not use GP-relative jumps +KBUILD_CFLAGS += -G0 +LDFLAGS_vmlinux += -G0 + +# Do not use single-byte enums; these will overflow. +KBUILD_CFLAGS += -fno-short-enums + +# We must use long-calls: +KBUILD_CFLAGS += -mlong-calls + +# Modules must use either long-calls, or use pic/plt. +# Use long-calls for now, it's easier. And faster. +# KBUILD_CFLAGS_MODULE += -fPIC +# KBUILD_LDFLAGS_MODULE += -shared +KBUILD_CFLAGS_MODULE += -mlong-calls + +cflags-y += $(call cc-option,-mv${CONFIG_HEXAGON_ARCH_VERSION}) +aflags-y += $(call cc-option,-mv${CONFIG_HEXAGON_ARCH_VERSION}) +ldflags-y += $(call cc-option,-mv${CONFIG_HEXAGON_ARCH_VERSION}) + +KBUILD_CFLAGS += $(cflags-y) +KBUILD_AFLAGS += $(aflags-y) +KBUILD_LDFLAGS += $(ldflags-y) + +# Thread-info register will be r19. This value is not configureable; +# it is hard-coded in several files. +TIR_NAME := r19 +KBUILD_CFLAGS += -ffixed-$(TIR_NAME) -DTHREADINFO_REG=$(TIR_NAME) -D__linux__ +KBUILD_AFLAGS += -DTHREADINFO_REG=$(TIR_NAME) + +# Disable HexagonConstExtenders pass for LLVM versions prior to 19.1.0 +# https://github.com/llvm/llvm-project/issues/99714 +ifneq ($(call clang-min-version, 190100),y) +KBUILD_CFLAGS += -mllvm -hexagon-cext=false +endif -- cgit v1.3.1