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, 153 insertions, 0 deletions

diff --git a/arch/powerpc/boot/wii.c b/arch/powerpc/boot/wii.c
new file mode 100644
index 000000000..59406ad04
--- /dev/null
+++ b/arch/powerpc/boot/wii.c
@@ -0,0 +1,153 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * arch/powerpc/boot/wii.c
+ *
+ * Nintendo Wii bootwrapper support
+ * Copyright (C) 2008-2009 The GameCube Linux Team
+ * Copyright (C) 2008,2009 Albert Herranz
+ */
+
+#include <stddef.h>
+#include "stdio.h"
+#include "types.h"
+#include "io.h"
+#include "ops.h"
+
+#include "ugecon.h"
+
+BSS_STACK(8192);
+
+#define HW_REG(x)		((void *)(x))
+
+#define EXI_CTRL		HW_REG(0x0d800070)
+#define EXI_CTRL_ENABLE		(1<<0)
+
+#define MEM2_TOP		(0x10000000 + 64*1024*1024)
+#define FIRMWARE_DEFAULT_SIZE	(12*1024*1024)
+
+
+struct mipc_infohdr {
+	char magic[3];
+	u8 version;
+	u32 mem2_boundary;
+	u32 ipc_in;
+	size_t ipc_in_size;
+	u32 ipc_out;
+	size_t ipc_out_size;
+};
+
+static int mipc_check_address(u32 pa)
+{
+	/* only MEM2 addresses */
+	if (pa < 0x10000000 || pa > 0x14000000)
+		return -EINVAL;
+	return 0;
+}
+
+static struct mipc_infohdr *mipc_get_infohdr(void)
+{
+	struct mipc_infohdr **hdrp, *hdr;
+
+	/* 'mini' header pointer is the last word of MEM2 memory */
+	hdrp = (struct mipc_infohdr **)0x13fffffc;
+	if (mipc_check_address((u32)hdrp)) {
+		printf("mini: invalid hdrp %08X\n", (u32)hdrp);
+		hdr = NULL;
+		goto out;
+	}
+
+	hdr = *hdrp;
+	if (mipc_check_address((u32)hdr)) {
+		printf("mini: invalid hdr %08X\n", (u32)hdr);
+		hdr = NULL;
+		goto out;
+	}
+	if (memcmp(hdr->magic, "IPC", 3)) {
+		printf("mini: invalid magic\n");
+		hdr = NULL;
+		goto out;
+	}
+
+out:
+	return hdr;
+}
+
+static int mipc_get_mem2_boundary(u32 *mem2_boundary)
+{
+	struct mipc_infohdr *hdr;
+	int error;
+
+	hdr = mipc_get_infohdr();
+	if (!hdr) {
+		error = -1;
+		goto out;
+	}
+
+	if (mipc_check_address(hdr->mem2_boundary)) {
+		printf("mini: invalid mem2_boundary %08X\n",
+		       hdr->mem2_boundary);
+		error = -EINVAL;
+		goto out;
+	}
+	*mem2_boundary = hdr->mem2_boundary;
+	error = 0;
+out:
+	return error;
+
+}
+
+static void platform_fixups(void)
+{
+	void *mem;
+	u32 reg[4];
+	u32 mem2_boundary;
+	int len;
+	int error;
+
+	mem = finddevice("/memory");
+	if (!mem)
+		fatal("Can't find memory node\n");
+
+	/* two ranges of (address, size) words */
+	len = getprop(mem, "reg", reg, sizeof(reg));
+	if (len != sizeof(reg)) {
+		/* nothing to do */
+		goto out;
+	}
+
+	/* retrieve MEM2 boundary from 'mini' */
+	error = mipc_get_mem2_boundary(&mem2_boundary);
+	if (error) {
+		/* if that fails use a sane value */
+		mem2_boundary = MEM2_TOP - FIRMWARE_DEFAULT_SIZE;
+	}
+
+	if (mem2_boundary > reg[2] && mem2_boundary < reg[2] + reg[3]) {
+		reg[3] = mem2_boundary - reg[2];
+		printf("top of MEM2 @ %08X\n", reg[2] + reg[3]);
+		setprop(mem, "reg", reg, sizeof(reg));
+	}
+
+out:
+	return;
+}
+
+void platform_init(unsigned long r3, unsigned long r4, unsigned long r5)
+{
+	u32 heapsize = 24*1024*1024 - (u32)_end;
+
+	simple_alloc_init(_end, heapsize, 32, 64);
+	fdt_init(_dtb_start);
+
+	/*
+	 * 'mini' boots the Broadway processor with EXI disabled.
+	 * We need it enabled before probing for the USB Gecko.
+	 */
+	out_be32(EXI_CTRL, in_be32(EXI_CTRL) | EXI_CTRL_ENABLE);
+
+	if (ug_probe())
+		console_ops.write = ug_console_write;
+
+	platform_ops.fixups = platform_fixups;
+}
+