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/an8855-efuse.c | 67 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 67 insertions(+) create mode 100644 drivers/nvmem/an8855-efuse.c (limited to 'drivers/nvmem/an8855-efuse.c') diff --git a/drivers/nvmem/an8855-efuse.c b/drivers/nvmem/an8855-efuse.c new file mode 100644 index 000000000..ed0840f79 --- /dev/null +++ b/drivers/nvmem/an8855-efuse.c @@ -0,0 +1,67 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Airoha AN8855 Switch EFUSE Driver + */ + +#include +#include +#include +#include + +#define AN8855_EFUSE_CELL 50 + +#define AN8855_EFUSE_DATA0 0x1000a500 +#define AN8855_EFUSE_R50O GENMASK(30, 24) + +static int an8855_efuse_read(void *context, unsigned int offset, + void *val, size_t bytes) +{ + struct regmap *regmap = context; + + return regmap_bulk_read(regmap, AN8855_EFUSE_DATA0 + offset, + val, bytes / sizeof(u32)); +} + +static int an8855_efuse_probe(struct platform_device *pdev) +{ + struct nvmem_config an8855_nvmem_config = { + .name = "an8855-efuse", + .size = AN8855_EFUSE_CELL * sizeof(u32), + .stride = sizeof(u32), + .word_size = sizeof(u32), + .reg_read = an8855_efuse_read, + }; + struct device *dev = &pdev->dev; + struct nvmem_device *nvmem; + struct regmap *regmap; + + /* Assign NVMEM priv to MFD regmap */ + regmap = dev_get_regmap(dev->parent, NULL); + if (!regmap) + return -ENOENT; + + an8855_nvmem_config.priv = regmap; + an8855_nvmem_config.dev = dev; + nvmem = devm_nvmem_register(dev, &an8855_nvmem_config); + + return PTR_ERR_OR_ZERO(nvmem); +} + +static const struct of_device_id an8855_efuse_of_match[] = { + { .compatible = "airoha,an8855-efuse", }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, an8855_efuse_of_match); + +static struct platform_driver an8855_efuse_driver = { + .probe = an8855_efuse_probe, + .driver = { + .name = "an8855-efuse", + .of_match_table = an8855_efuse_of_match, + }, +}; +module_platform_driver(an8855_efuse_driver); + +MODULE_AUTHOR("Christian Marangi "); +MODULE_DESCRIPTION("Driver for AN8855 Switch EFUSE"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1