selftests/bpf: Add a test for objects stuck in free_by_rcu_ttracegrafted

Delete all elements of BPF_F_NO_PREALLOC hash map in one batch. The first
free_bulk() starts RCU tasks trace GP and the rest of the elements are
freed while it's in flight. Wait for call_rcu_ttrace_in_progress to clear
in bpf_mem_cache of every cpu and check that free_by_rcu_ttrace and
waiting_for_gp_ttrace lists are empty.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20260930095920.601738-4-alexei.starovoitov@gmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>

1 files changed, 88 insertions, 0 deletions

diff --git a/drivers/fpga/xilinx-spi.c b/drivers/fpga/xilinx-spi.c
new file mode 100644
index 000000000..765626cad
--- /dev/null
+++ b/drivers/fpga/xilinx-spi.c
@@ -0,0 +1,88 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Xilinx Spartan6 and 7 Series Slave Serial SPI Driver
+ *
+ * Copyright (C) 2017 DENX Software Engineering
+ *
+ * Anatolij Gustschin <agust@denx.de>
+ *
+ * Manage Xilinx FPGA firmware that is loaded over SPI using
+ * the slave serial configuration interface.
+ */
+
+#include "xilinx-core.h"
+
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/spi/spi.h>
+
+static int xilinx_spi_write(struct xilinx_fpga_core *core, const char *buf,
+			    size_t count)
+{
+	struct spi_device *spi = to_spi_device(core->dev);
+	const char *fw_data = buf;
+	const char *fw_data_end = fw_data + count;
+
+	while (fw_data < fw_data_end) {
+		size_t remaining, stride;
+		int ret;
+
+		remaining = fw_data_end - fw_data;
+		stride = min_t(size_t, remaining, SZ_4K);
+
+		ret = spi_write(spi, fw_data, stride);
+		if (ret) {
+			dev_err(core->dev, "SPI error in firmware write: %d\n",
+				ret);
+			return ret;
+		}
+		fw_data += stride;
+	}
+
+	return 0;
+}
+
+static int xilinx_spi_probe(struct spi_device *spi)
+{
+	struct xilinx_fpga_core *core;
+
+	core = devm_kzalloc(&spi->dev, sizeof(*core), GFP_KERNEL);
+	if (!core)
+		return -ENOMEM;
+
+	core->dev = &spi->dev;
+	core->write = xilinx_spi_write;
+
+	return xilinx_core_probe(core);
+}
+
+static const struct spi_device_id xilinx_spi_ids[] = {
+	{ "fpga-slave-serial" },
+	{ },
+};
+MODULE_DEVICE_TABLE(spi, xilinx_spi_ids);
+
+#ifdef CONFIG_OF
+static const struct of_device_id xlnx_spi_of_match[] = {
+	{
+		.compatible = "xlnx,fpga-slave-serial",
+	},
+	{}
+};
+MODULE_DEVICE_TABLE(of, xlnx_spi_of_match);
+#endif
+
+static struct spi_driver xilinx_slave_spi_driver = {
+	.driver = {
+		.name = "xlnx-slave-spi",
+		.of_match_table = of_match_ptr(xlnx_spi_of_match),
+	},
+	.probe = xilinx_spi_probe,
+	.id_table = xilinx_spi_ids,
+};
+
+module_spi_driver(xilinx_slave_spi_driver)
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Anatolij Gustschin <agust@denx.de>");
+MODULE_DESCRIPTION("Load Xilinx FPGA firmware over SPI");