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/powerpc/sysdev/dart.h | 64 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 64 insertions(+) create mode 100644 arch/powerpc/sysdev/dart.h (limited to 'arch/powerpc/sysdev/dart.h') diff --git a/arch/powerpc/sysdev/dart.h b/arch/powerpc/sysdev/dart.h new file mode 100644 index 000000000..7f5df03d3 --- /dev/null +++ b/arch/powerpc/sysdev/dart.h @@ -0,0 +1,64 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Copyright (C) 2004 Olof Johansson , IBM Corporation + */ + +#ifndef _POWERPC_SYSDEV_DART_H +#define _POWERPC_SYSDEV_DART_H + + +/* Offset from base to control register */ +#define DART_CNTL 0 + +/* Offset from base to exception register */ +#define DART_EXCP_U3 0x10 +/* Offset from base to TLB tag registers */ +#define DART_TAGS_U3 0x1000 + +/* U4 registers */ +#define DART_BASE_U4 0x10 +#define DART_SIZE_U4 0x20 +#define DART_EXCP_U4 0x30 +#define DART_TAGS_U4 0x1000 + +/* Control Register fields */ + +/* U3 registers */ +#define DART_CNTL_U3_BASE_MASK 0xfffff +#define DART_CNTL_U3_BASE_SHIFT 12 +#define DART_CNTL_U3_FLUSHTLB 0x400 +#define DART_CNTL_U3_ENABLE 0x200 +#define DART_CNTL_U3_SIZE_MASK 0x1ff +#define DART_CNTL_U3_SIZE_SHIFT 0 + +/* U4 registers */ +#define DART_BASE_U4_BASE_MASK 0xffffff +#define DART_BASE_U4_BASE_SHIFT 0 +#define DART_CNTL_U4_ENABLE 0x80000000 +#define DART_CNTL_U4_IONE 0x40000000 +#define DART_CNTL_U4_FLUSHTLB 0x20000000 +#define DART_CNTL_U4_IDLE 0x10000000 +#define DART_CNTL_U4_PAR_EN 0x08000000 +#define DART_CNTL_U4_IONE_MASK 0x07ffffff +#define DART_SIZE_U4_SIZE_MASK 0x1fff +#define DART_SIZE_U4_SIZE_SHIFT 0 + +#define DART_REG(r) (dart + ((r) >> 2)) +#define DART_IN(r) (in_be32(DART_REG(r))) +#define DART_OUT(r,v) (out_be32(DART_REG(r), (v))) + + +/* size of table in pages */ + + +/* DART table fields */ + +#define DARTMAP_VALID 0x80000000 +#define DARTMAP_RPNMASK 0x00ffffff + + +#define DART_PAGE_SHIFT 12 +#define DART_PAGE_SIZE (1 << DART_PAGE_SHIFT) + + +#endif /* _POWERPC_SYSDEV_DART_H */ -- cgit v1.3.1