bpf: mark a NULL kfunc argument precisegrafted

check_kfunc_arg() allows bpf_register_is_null() for nullable arguments
w/o marking the underlying scalar register precise. Hence a checkpoint
created on such a path would prune against arbitrary scalar value.

Fixes: 3bda08b63670 ("bpf: Allow NULL buffers in bpf_dynptr_slice(_rw)")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-5-0f5a360ff15d@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 92 insertions, 0 deletions

diff --git a/drivers/pci/controller/pci-host-generic.c b/drivers/pci/controller/pci-host-generic.c
new file mode 100644
index 000000000..c1bc0d343
--- /dev/null
+++ b/drivers/pci/controller/pci-host-generic.c
@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Simple, generic PCI host controller driver targeting firmware-initialised
+ * systems and virtual machines (e.g. the PCI emulation provided by kvmtool).
+ *
+ * Copyright (C) 2014 ARM Limited
+ *
+ * Author: Will Deacon <will.deacon@arm.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/pci-ecam.h>
+#include <linux/platform_device.h>
+
+#include "pci-host-common.h"
+
+static const struct pci_ecam_ops gen_pci_cfg_cam_bus_ops = {
+	.bus_shift	= 16,
+	.pci_ops	= {
+		.map_bus	= pci_ecam_map_bus,
+		.read		= pci_generic_config_read,
+		.write		= pci_generic_config_write,
+	}
+};
+
+static bool pci_dw_valid_device(struct pci_bus *bus, unsigned int devfn)
+{
+	struct pci_config_window *cfg = bus->sysdata;
+
+	/*
+	 * The Synopsys DesignWare PCIe controller in ECAM mode will not filter
+	 * type 0 config TLPs sent to devices 1 and up on its downstream port,
+	 * resulting in devices appearing multiple times on bus 0 unless we
+	 * filter out those accesses here.
+	 */
+	if (bus->number == cfg->busr.start && PCI_SLOT(devfn) > 0)
+		return false;
+
+	return true;
+}
+
+static void __iomem *pci_dw_ecam_map_bus(struct pci_bus *bus,
+					 unsigned int devfn, int where)
+{
+	if (!pci_dw_valid_device(bus, devfn))
+		return NULL;
+
+	return pci_ecam_map_bus(bus, devfn, where);
+}
+
+static const struct pci_ecam_ops pci_dw_ecam_bus_ops = {
+	.pci_ops	= {
+		.map_bus	= pci_dw_ecam_map_bus,
+		.read		= pci_generic_config_read,
+		.write		= pci_generic_config_write,
+	}
+};
+
+static const struct of_device_id gen_pci_of_match[] = {
+	{ .compatible = "pci-host-cam-generic",
+	  .data = &gen_pci_cfg_cam_bus_ops },
+
+	{ .compatible = "pci-host-ecam-generic",
+	  .data = &pci_generic_ecam_ops },
+
+	{ .compatible = "marvell,armada8k-pcie-ecam",
+	  .data = &pci_dw_ecam_bus_ops },
+
+	{ .compatible = "socionext,synquacer-pcie-ecam",
+	  .data = &pci_dw_ecam_bus_ops },
+
+	{ .compatible = "snps,dw-pcie-ecam",
+	  .data = &pci_dw_ecam_bus_ops },
+
+	{ },
+};
+MODULE_DEVICE_TABLE(of, gen_pci_of_match);
+
+static struct platform_driver gen_pci_driver = {
+	.driver = {
+		.name = "pci-host-generic",
+		.of_match_table = gen_pci_of_match,
+	},
+	.probe = pci_host_common_probe,
+	.remove = pci_host_common_remove,
+};
+module_platform_driver(gen_pci_driver);
+
+MODULE_DESCRIPTION("Generic PCI host controller driver");
+MODULE_LICENSE("GPL v2");