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/nvmem/apple-spmi-nvmem.c | 78 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 78 insertions(+) create mode 100644 drivers/nvmem/apple-spmi-nvmem.c (limited to 'drivers/nvmem/apple-spmi-nvmem.c') diff --git a/drivers/nvmem/apple-spmi-nvmem.c b/drivers/nvmem/apple-spmi-nvmem.c new file mode 100644 index 000000000..7acb0c07d --- /dev/null +++ b/drivers/nvmem/apple-spmi-nvmem.c @@ -0,0 +1,78 @@ +// SPDX-License-Identifier: GPL-2.0-only OR MIT +/* + * Apple SPMI NVMEM driver + * + * Copyright The Asahi Linux Contributors + */ + +#include +#include +#include +#include +#include +#include + +static const struct regmap_config apple_spmi_regmap_config = { + .reg_bits = 16, + .val_bits = 8, + .max_register = 0xffff, +}; + +static int apple_spmi_nvmem_read(void *priv, unsigned int offset, void *val, + size_t bytes) +{ + struct regmap *map = priv; + + return regmap_bulk_read(map, offset, val, bytes); +} + +static int apple_spmi_nvmem_write(void *priv, unsigned int offset, void *val, + size_t bytes) +{ + struct regmap *map = priv; + + return regmap_bulk_write(map, offset, val, bytes); +} + +static int apple_spmi_nvmem_probe(struct spmi_device *sdev) +{ + struct regmap *regmap; + struct nvmem_config nvmem_cfg = { + .dev = &sdev->dev, + .name = "spmi_nvmem", + .id = NVMEM_DEVID_AUTO, + .word_size = 1, + .stride = 1, + .size = 0xffff, + .reg_read = apple_spmi_nvmem_read, + .reg_write = apple_spmi_nvmem_write, + }; + + regmap = devm_regmap_init_spmi_ext(sdev, &apple_spmi_regmap_config); + if (IS_ERR(regmap)) + return PTR_ERR(regmap); + + nvmem_cfg.priv = regmap; + + return PTR_ERR_OR_ZERO(devm_nvmem_register(&sdev->dev, &nvmem_cfg)); +} + +static const struct of_device_id apple_spmi_nvmem_id_table[] = { + { .compatible = "apple,spmi-nvmem" }, + { }, +}; +MODULE_DEVICE_TABLE(of, apple_spmi_nvmem_id_table); + +static struct spmi_driver apple_spmi_nvmem_driver = { + .probe = apple_spmi_nvmem_probe, + .driver = { + .name = "apple-spmi-nvmem", + .of_match_table = apple_spmi_nvmem_id_table, + }, +}; + +module_spmi_driver(apple_spmi_nvmem_driver); + +MODULE_LICENSE("Dual MIT/GPL"); +MODULE_AUTHOR("Hector Martin "); +MODULE_DESCRIPTION("Apple SPMI NVMEM driver"); -- cgit v1.3.1