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/layerscape-sfp.c | 108 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 108 insertions(+) create mode 100644 drivers/nvmem/layerscape-sfp.c (limited to 'drivers/nvmem/layerscape-sfp.c') diff --git a/drivers/nvmem/layerscape-sfp.c b/drivers/nvmem/layerscape-sfp.c new file mode 100644 index 000000000..c1521afd5 --- /dev/null +++ b/drivers/nvmem/layerscape-sfp.c @@ -0,0 +1,108 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Layerscape SFP driver + * + * Copyright (c) 2022 Michael Walle + * + */ + +#include +#include +#include +#include +#include +#include +#include + +#define LAYERSCAPE_SFP_OTP_OFFSET 0x0200 + +struct layerscape_sfp_priv { + struct regmap *regmap; +}; + +struct layerscape_sfp_data { + int size; + enum regmap_endian endian; +}; + +static int layerscape_sfp_read(void *context, unsigned int offset, void *val, + size_t bytes) +{ + struct layerscape_sfp_priv *priv = context; + + return regmap_bulk_read(priv->regmap, + LAYERSCAPE_SFP_OTP_OFFSET + offset, val, + bytes / 4); +} + +static struct nvmem_config layerscape_sfp_nvmem_config = { + .name = "fsl-sfp", + .reg_read = layerscape_sfp_read, + .word_size = 4, + .stride = 4, +}; + +static int layerscape_sfp_probe(struct platform_device *pdev) +{ + const struct layerscape_sfp_data *data; + struct layerscape_sfp_priv *priv; + struct nvmem_device *nvmem; + struct regmap_config config = { 0 }; + void __iomem *base; + + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(base)) + return PTR_ERR(base); + + data = device_get_match_data(&pdev->dev); + config.reg_bits = 32; + config.reg_stride = 4; + config.val_bits = 32; + config.val_format_endian = data->endian; + config.max_register = LAYERSCAPE_SFP_OTP_OFFSET + data->size - 4; + priv->regmap = devm_regmap_init_mmio(&pdev->dev, base, &config); + if (IS_ERR(priv->regmap)) + return PTR_ERR(priv->regmap); + + layerscape_sfp_nvmem_config.size = data->size; + layerscape_sfp_nvmem_config.dev = &pdev->dev; + layerscape_sfp_nvmem_config.priv = priv; + + nvmem = devm_nvmem_register(&pdev->dev, &layerscape_sfp_nvmem_config); + + return PTR_ERR_OR_ZERO(nvmem); +} + +static const struct layerscape_sfp_data ls1021a_data = { + .size = 0x88, + .endian = REGMAP_ENDIAN_BIG, +}; + +static const struct layerscape_sfp_data ls1028a_data = { + .size = 0x88, + .endian = REGMAP_ENDIAN_LITTLE, +}; + +static const struct of_device_id layerscape_sfp_dt_ids[] = { + { .compatible = "fsl,ls1021a-sfp", .data = &ls1021a_data }, + { .compatible = "fsl,ls1028a-sfp", .data = &ls1028a_data }, + {}, +}; +MODULE_DEVICE_TABLE(of, layerscape_sfp_dt_ids); + +static struct platform_driver layerscape_sfp_driver = { + .probe = layerscape_sfp_probe, + .driver = { + .name = "layerscape_sfp", + .of_match_table = layerscape_sfp_dt_ids, + }, +}; +module_platform_driver(layerscape_sfp_driver); + +MODULE_AUTHOR("Michael Walle "); +MODULE_DESCRIPTION("Layerscape Security Fuse Processor driver"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1