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/gpio/gpio-octeon.c | 140 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 140 insertions(+) create mode 100644 drivers/gpio/gpio-octeon.c (limited to 'drivers/gpio/gpio-octeon.c') diff --git a/drivers/gpio/gpio-octeon.c b/drivers/gpio/gpio-octeon.c new file mode 100644 index 000000000..777e20c60 --- /dev/null +++ b/drivers/gpio/gpio-octeon.c @@ -0,0 +1,140 @@ +/* + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (C) 2011, 2012 Cavium Inc. + */ + +#include +#include +#include +#include +#include + +#include +#include + +#define RX_DAT 0x80 +#define TX_SET 0x88 +#define TX_CLEAR 0x90 +/* + * The address offset of the GPIO configuration register for a given + * line. + */ +static unsigned int bit_cfg_reg(unsigned int offset) +{ + /* + * The register stride is 8, with a discontinuity after the + * first 16. + */ + if (offset < 16) + return 8 * offset; + else + return 8 * (offset - 16) + 0x100; +} + +struct octeon_gpio { + struct gpio_chip chip; + u64 register_base; +}; + +static int octeon_gpio_dir_in(struct gpio_chip *chip, unsigned offset) +{ + struct octeon_gpio *gpio = gpiochip_get_data(chip); + + cvmx_write_csr(gpio->register_base + bit_cfg_reg(offset), 0); + return 0; +} + +static int octeon_gpio_set(struct gpio_chip *chip, unsigned int offset, + int value) +{ + struct octeon_gpio *gpio = gpiochip_get_data(chip); + u64 mask = 1ull << offset; + u64 reg = gpio->register_base + (value ? TX_SET : TX_CLEAR); + cvmx_write_csr(reg, mask); + + return 0; +} + +static int octeon_gpio_dir_out(struct gpio_chip *chip, unsigned offset, + int value) +{ + struct octeon_gpio *gpio = gpiochip_get_data(chip); + union cvmx_gpio_bit_cfgx cfgx; + + octeon_gpio_set(chip, offset, value); + + cfgx.u64 = 0; + cfgx.s.tx_oe = 1; + + cvmx_write_csr(gpio->register_base + bit_cfg_reg(offset), cfgx.u64); + return 0; +} + +static int octeon_gpio_get(struct gpio_chip *chip, unsigned offset) +{ + struct octeon_gpio *gpio = gpiochip_get_data(chip); + u64 read_bits = cvmx_read_csr(gpio->register_base + RX_DAT); + + return ((1ull << offset) & read_bits) != 0; +} + +static int octeon_gpio_probe(struct platform_device *pdev) +{ + struct octeon_gpio *gpio; + struct gpio_chip *chip; + void __iomem *reg_base; + int err = 0; + + gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL); + if (!gpio) + return -ENOMEM; + chip = &gpio->chip; + + reg_base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(reg_base)) + return PTR_ERR(reg_base); + + gpio->register_base = (u64)reg_base; + pdev->dev.platform_data = chip; + chip->label = "octeon-gpio"; + chip->parent = &pdev->dev; + chip->owner = THIS_MODULE; + chip->base = 0; + chip->can_sleep = false; + chip->ngpio = 20; + chip->direction_input = octeon_gpio_dir_in; + chip->get = octeon_gpio_get; + chip->direction_output = octeon_gpio_dir_out; + chip->set = octeon_gpio_set; + err = devm_gpiochip_add_data(&pdev->dev, chip, gpio); + if (err) + return err; + + dev_info(&pdev->dev, "OCTEON GPIO driver probed.\n"); + return 0; +} + +static const struct of_device_id octeon_gpio_match[] = { + { + .compatible = "cavium,octeon-3860-gpio", + }, + {}, +}; +MODULE_DEVICE_TABLE(of, octeon_gpio_match); + +static struct platform_driver octeon_gpio_driver = { + .driver = { + .name = "octeon_gpio", + .of_match_table = octeon_gpio_match, + }, + .probe = octeon_gpio_probe, +}; + +module_platform_driver(octeon_gpio_driver); + +MODULE_DESCRIPTION("Cavium Inc. OCTEON GPIO Driver"); +MODULE_AUTHOR("David Daney"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1