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 --- drivers/clk/actions/owl-divider.c | 84 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 84 insertions(+) create mode 100644 drivers/clk/actions/owl-divider.c (limited to 'drivers/clk/actions/owl-divider.c') diff --git a/drivers/clk/actions/owl-divider.c b/drivers/clk/actions/owl-divider.c new file mode 100644 index 000000000..316ace80e --- /dev/null +++ b/drivers/clk/actions/owl-divider.c @@ -0,0 +1,84 @@ +// SPDX-License-Identifier: GPL-2.0+ +// +// OWL divider clock driver +// +// Copyright (c) 2014 Actions Semi Inc. +// Author: David Liu +// +// Copyright (c) 2018 Linaro Ltd. +// Author: Manivannan Sadhasivam + +#include +#include + +#include "owl-divider.h" + +static int owl_divider_determine_rate(struct clk_hw *hw, + struct clk_rate_request *req) +{ + struct owl_divider *div = hw_to_owl_divider(hw); + + return divider_determine_rate(hw, req, div->div_hw.table, + div->div_hw.width, div->div_hw.div_flags); +} + +unsigned long owl_divider_helper_recalc_rate(struct owl_clk_common *common, + const struct owl_divider_hw *div_hw, + unsigned long parent_rate) +{ + unsigned long val; + unsigned int reg; + + regmap_read(common->regmap, div_hw->reg, ®); + val = reg >> div_hw->shift; + val &= (1 << div_hw->width) - 1; + + return divider_recalc_rate(&common->hw, parent_rate, + val, div_hw->table, + div_hw->div_flags, + div_hw->width); +} + +static unsigned long owl_divider_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct owl_divider *div = hw_to_owl_divider(hw); + + return owl_divider_helper_recalc_rate(&div->common, + &div->div_hw, parent_rate); +} + +int owl_divider_helper_set_rate(const struct owl_clk_common *common, + const struct owl_divider_hw *div_hw, + unsigned long rate, + unsigned long parent_rate) +{ + unsigned long val; + unsigned int reg; + + val = divider_get_val(rate, parent_rate, div_hw->table, + div_hw->width, 0); + + regmap_read(common->regmap, div_hw->reg, ®); + reg &= ~GENMASK(div_hw->width + div_hw->shift - 1, div_hw->shift); + + regmap_write(common->regmap, div_hw->reg, + reg | (val << div_hw->shift)); + + return 0; +} + +static int owl_divider_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + struct owl_divider *div = hw_to_owl_divider(hw); + + return owl_divider_helper_set_rate(&div->common, &div->div_hw, + rate, parent_rate); +} + +const struct clk_ops owl_divider_ops = { + .recalc_rate = owl_divider_recalc_rate, + .determine_rate = owl_divider_determine_rate, + .set_rate = owl_divider_set_rate, +}; -- cgit v1.3.1