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, 210 insertions, 0 deletions

diff --git a/drivers/ssb/host_soc.c b/drivers/ssb/host_soc.c
new file mode 100644
index 000000000..3b4384805
--- /dev/null
+++ b/drivers/ssb/host_soc.c
@@ -0,0 +1,210 @@
+/*
+ * Sonics Silicon Backplane SoC host related functions.
+ * Subsystem core
+ *
+ * Copyright 2005, Broadcom Corporation
+ * Copyright 2006, 2007, Michael Buesch <m@bues.ch>
+ *
+ * Licensed under the GNU/GPL. See COPYING for details.
+ */
+
+#include "ssb_private.h"
+
+#include <linux/bcm47xx_nvram.h>
+#include <linux/ssb/ssb.h>
+
+static u8 ssb_host_soc_read8(struct ssb_device *dev, u16 offset)
+{
+	struct ssb_bus *bus = dev->bus;
+
+	offset += dev->core_index * SSB_CORE_SIZE;
+	return readb(bus->mmio + offset);
+}
+
+static u16 ssb_host_soc_read16(struct ssb_device *dev, u16 offset)
+{
+	struct ssb_bus *bus = dev->bus;
+
+	offset += dev->core_index * SSB_CORE_SIZE;
+	return readw(bus->mmio + offset);
+}
+
+static u32 ssb_host_soc_read32(struct ssb_device *dev, u16 offset)
+{
+	struct ssb_bus *bus = dev->bus;
+
+	offset += dev->core_index * SSB_CORE_SIZE;
+	return readl(bus->mmio + offset);
+}
+
+#ifdef CONFIG_SSB_BLOCKIO
+static void ssb_host_soc_block_read(struct ssb_device *dev, void *buffer,
+				    size_t count, u16 offset, u8 reg_width)
+{
+	struct ssb_bus *bus = dev->bus;
+	void __iomem *addr;
+
+	offset += dev->core_index * SSB_CORE_SIZE;
+	addr = bus->mmio + offset;
+
+	switch (reg_width) {
+	case sizeof(u8): {
+		u8 *buf = buffer;
+
+		while (count) {
+			*buf = __raw_readb(addr);
+			buf++;
+			count--;
+		}
+		break;
+	}
+	case sizeof(u16): {
+		__le16 *buf = buffer;
+
+		WARN_ON(count & 1);
+		while (count) {
+			*buf = (__force __le16)__raw_readw(addr);
+			buf++;
+			count -= 2;
+		}
+		break;
+	}
+	case sizeof(u32): {
+		__le32 *buf = buffer;
+
+		WARN_ON(count & 3);
+		while (count) {
+			*buf = (__force __le32)__raw_readl(addr);
+			buf++;
+			count -= 4;
+		}
+		break;
+	}
+	default:
+		WARN_ON(1);
+	}
+}
+#endif /* CONFIG_SSB_BLOCKIO */
+
+static void ssb_host_soc_write8(struct ssb_device *dev, u16 offset, u8 value)
+{
+	struct ssb_bus *bus = dev->bus;
+
+	offset += dev->core_index * SSB_CORE_SIZE;
+	writeb(value, bus->mmio + offset);
+}
+
+static void ssb_host_soc_write16(struct ssb_device *dev, u16 offset, u16 value)
+{
+	struct ssb_bus *bus = dev->bus;
+
+	offset += dev->core_index * SSB_CORE_SIZE;
+	writew(value, bus->mmio + offset);
+}
+
+static void ssb_host_soc_write32(struct ssb_device *dev, u16 offset, u32 value)
+{
+	struct ssb_bus *bus = dev->bus;
+
+	offset += dev->core_index * SSB_CORE_SIZE;
+	writel(value, bus->mmio + offset);
+}
+
+#ifdef CONFIG_SSB_BLOCKIO
+static void ssb_host_soc_block_write(struct ssb_device *dev, const void *buffer,
+				     size_t count, u16 offset, u8 reg_width)
+{
+	struct ssb_bus *bus = dev->bus;
+	void __iomem *addr;
+
+	offset += dev->core_index * SSB_CORE_SIZE;
+	addr = bus->mmio + offset;
+
+	switch (reg_width) {
+	case sizeof(u8): {
+		const u8 *buf = buffer;
+
+		while (count) {
+			__raw_writeb(*buf, addr);
+			buf++;
+			count--;
+		}
+		break;
+	}
+	case sizeof(u16): {
+		const __le16 *buf = buffer;
+
+		WARN_ON(count & 1);
+		while (count) {
+			__raw_writew((__force u16)(*buf), addr);
+			buf++;
+			count -= 2;
+		}
+		break;
+	}
+	case sizeof(u32): {
+		const __le32 *buf = buffer;
+
+		WARN_ON(count & 3);
+		while (count) {
+			__raw_writel((__force u32)(*buf), addr);
+			buf++;
+			count -= 4;
+		}
+		break;
+	}
+	default:
+		WARN_ON(1);
+	}
+}
+#endif /* CONFIG_SSB_BLOCKIO */
+
+/* Ops for the plain SSB bus without a host-device (no PCI or PCMCIA). */
+const struct ssb_bus_ops ssb_host_soc_ops = {
+	.read8		= ssb_host_soc_read8,
+	.read16		= ssb_host_soc_read16,
+	.read32		= ssb_host_soc_read32,
+	.write8		= ssb_host_soc_write8,
+	.write16	= ssb_host_soc_write16,
+	.write32	= ssb_host_soc_write32,
+#ifdef CONFIG_SSB_BLOCKIO
+	.block_read	= ssb_host_soc_block_read,
+	.block_write	= ssb_host_soc_block_write,
+#endif
+};
+
+int ssb_host_soc_get_invariants(struct ssb_bus *bus,
+				struct ssb_init_invariants *iv)
+{
+	char buf[20];
+	int len, err;
+
+	/* Fill boardinfo structure */
+	memset(&iv->boardinfo, 0, sizeof(struct ssb_boardinfo));
+
+	len = bcm47xx_nvram_getenv("boardvendor", buf, sizeof(buf));
+	if (len > 0) {
+		err = kstrtou16(strim(buf), 0, &iv->boardinfo.vendor);
+		if (err)
+			pr_warn("Couldn't parse nvram board vendor entry with value \"%s\"\n",
+				buf);
+	}
+	if (!iv->boardinfo.vendor)
+		iv->boardinfo.vendor = SSB_BOARDVENDOR_BCM;
+
+	len = bcm47xx_nvram_getenv("boardtype", buf, sizeof(buf));
+	if (len > 0) {
+		err = kstrtou16(strim(buf), 0, &iv->boardinfo.type);
+		if (err)
+			pr_warn("Couldn't parse nvram board type entry with value \"%s\"\n",
+				buf);
+	}
+
+	memset(&iv->sprom, 0, sizeof(struct ssb_sprom));
+	ssb_fill_sprom_with_fallback(bus, &iv->sprom);
+
+	if (bcm47xx_nvram_getenv("cardbus", buf, sizeof(buf)) >= 0)
+		iv->has_cardbus_slot = !!simple_strtoul(buf, NULL, 10);
+
+	return 0;
+}