ftrace: Synchronize the initialization of ftrace_opsgrafted

There's some internal state that ftrace_ops needs to have set, but since
it can be declared outside of the ftrace.c code, it calls
ftrace_ops_init() on the ops in every global function. The issue is that
if two tasks call it on the same ops at the same time it is possible to
have the initialization of one corrupt the initialization of the other
call.

Create a ops_mutex to use to synchronize every initialization of the
ftrace_ops. The mutex is taken within checking the ftrace_ops flag that
states it was initializied but the flag is checked again after the mutex
has been taken. Checking first outside the mutex allows it to shortcut
having to take the mutex. But then the check needs to be done again after
the mute is taken in case of races.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home
Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock")
Reported-by: sashiko-bot@kernel.org
Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 91 insertions, 0 deletions

diff --git a/drivers/ata/ahci_octeon.c b/drivers/ata/ahci_octeon.c
new file mode 100644
index 000000000..9accf8923
--- /dev/null
+++ b/drivers/ata/ahci_octeon.c
@@ -0,0 +1,91 @@
+/*
+ * SATA glue for Cavium Octeon III SOCs.
+ *
+ *
+ * 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) 2010-2015 Cavium Networks
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/dma-mapping.h>
+#include <linux/platform_device.h>
+#include <linux/of_platform.h>
+
+#include <asm/octeon/octeon.h>
+
+#define CVMX_SATA_UCTL_SHIM_CFG		0xE8
+
+#define SATA_UCTL_ENDIAN_MODE_BIG	1
+#define SATA_UCTL_ENDIAN_MODE_LITTLE	0
+#define SATA_UCTL_ENDIAN_MODE_MASK	3
+
+#define SATA_UCTL_DMA_ENDIAN_MODE_SHIFT	8
+#define SATA_UCTL_CSR_ENDIAN_MODE_SHIFT	0
+#define SATA_UCTL_DMA_READ_CMD_SHIFT	12
+
+static int ahci_octeon_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *node = dev->of_node;
+	void __iomem *base;
+	u64 cfg;
+	int ret;
+
+	base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	cfg = cvmx_readq_csr(base + CVMX_SATA_UCTL_SHIM_CFG);
+
+	cfg &= ~(SATA_UCTL_ENDIAN_MODE_MASK << SATA_UCTL_DMA_ENDIAN_MODE_SHIFT);
+	cfg &= ~(SATA_UCTL_ENDIAN_MODE_MASK << SATA_UCTL_CSR_ENDIAN_MODE_SHIFT);
+
+#ifdef __BIG_ENDIAN
+	cfg |= SATA_UCTL_ENDIAN_MODE_BIG << SATA_UCTL_DMA_ENDIAN_MODE_SHIFT;
+	cfg |= SATA_UCTL_ENDIAN_MODE_BIG << SATA_UCTL_CSR_ENDIAN_MODE_SHIFT;
+#else
+	cfg |= SATA_UCTL_ENDIAN_MODE_LITTLE << SATA_UCTL_DMA_ENDIAN_MODE_SHIFT;
+	cfg |= SATA_UCTL_ENDIAN_MODE_LITTLE << SATA_UCTL_CSR_ENDIAN_MODE_SHIFT;
+#endif
+
+	cfg |= 1 << SATA_UCTL_DMA_READ_CMD_SHIFT;
+
+	cvmx_writeq_csr(base + CVMX_SATA_UCTL_SHIM_CFG, cfg);
+
+	if (!node) {
+		dev_err(dev, "no device node, failed to add octeon sata\n");
+		return -ENODEV;
+	}
+
+	ret = of_platform_populate(node, NULL, NULL, dev);
+	if (ret) {
+		dev_err(dev, "failed to add ahci-platform core\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id octeon_ahci_match[] = {
+	{ .compatible = "cavium,octeon-7130-sata-uctl", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, octeon_ahci_match);
+
+static struct platform_driver ahci_octeon_driver = {
+	.probe          = ahci_octeon_probe,
+	.driver         = {
+		.name   = "octeon-ahci",
+		.of_match_table = octeon_ahci_match,
+	},
+};
+
+module_platform_driver(ahci_octeon_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Cavium, Inc. <support@cavium.com>");
+MODULE_DESCRIPTION("Cavium Inc. sata config.");