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, 115 insertions, 0 deletions

diff --git a/arch/powerpc/boot/treeboot-currituck.c b/arch/powerpc/boot/treeboot-currituck.c
new file mode 100644
index 000000000..5b5363b74
--- /dev/null
+++ b/arch/powerpc/boot/treeboot-currituck.c
@@ -0,0 +1,115 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright © 2011 Tony Breeds IBM Corporation
+ *
+ * Based on earlier code:
+ *   Copyright (C) Paul Mackerras 1997.
+ *
+ *   Matt Porter <mporter@kernel.crashing.org>
+ *   Copyright 2002-2005 MontaVista Software Inc.
+ *
+ *   Eugene Surovegin <eugene.surovegin@zultys.com> or <ebs@ebshome.net>
+ *   Copyright (c) 2003, 2004 Zultys Technologies
+ *
+ *    Copyright 2007 David Gibson, IBM Corporation.
+ *    Copyright 2010 Ben. Herrenschmidt, IBM Corporation.
+ *    Copyright © 2011 David Kleikamp IBM Corporation
+ */
+#include <stdarg.h>
+#include <stddef.h>
+#include "types.h"
+#include "elf.h"
+#include "string.h"
+#include "stdio.h"
+#include "page.h"
+#include "ops.h"
+#include "reg.h"
+#include "io.h"
+#include "dcr.h"
+#include "4xx.h"
+#include "44x.h"
+#include "libfdt.h"
+
+BSS_STACK(4096);
+
+#define MAX_RANKS	0x4
+#define DDR3_MR0CF	0x80010011U
+
+static unsigned long long ibm_currituck_memsize;
+static unsigned long long ibm_currituck_detect_memsize(void)
+{
+	u32 reg;
+	unsigned i;
+	unsigned long long memsize = 0;
+
+	for(i = 0; i < MAX_RANKS; i++){
+		reg = mfdcrx(DDR3_MR0CF + i);
+
+		if (!(reg & 1))
+			continue;
+
+		reg &= 0x0000f000;
+		reg >>= 12;
+		memsize += (0x800000ULL << reg);
+	}
+
+	return memsize;
+}
+
+static void ibm_currituck_fixups(void)
+{
+	void *devp = finddevice("/");
+	u32 dma_ranges[7];
+
+	dt_fixup_memory(0x0ULL,  ibm_currituck_memsize);
+
+	while ((devp = find_node_by_devtype(devp, "pci"))) {
+		if (getprop(devp, "dma-ranges", dma_ranges, sizeof(dma_ranges)) < 0) {
+			printf("%s: Failed to get dma-ranges\r\n", __func__);
+			continue;
+		}
+
+		dma_ranges[5] = ibm_currituck_memsize >> 32;
+		dma_ranges[6] = ibm_currituck_memsize & 0xffffffffUL;
+
+		setprop(devp, "dma-ranges", dma_ranges, sizeof(dma_ranges));
+	}
+}
+
+#define SPRN_PIR	0x11E	/* Processor Identification Register */
+void platform_init(void)
+{
+	unsigned long end_of_ram, avail_ram;
+	u32 pir_reg;
+	int node, size;
+	const u32 *timebase;
+
+	ibm_currituck_memsize = ibm_currituck_detect_memsize();
+	if (ibm_currituck_memsize >> 32)
+		end_of_ram = ~0UL;
+	else
+		end_of_ram = ibm_currituck_memsize;
+	avail_ram = end_of_ram - (unsigned long)_end;
+
+	simple_alloc_init(_end, avail_ram, 128, 64);
+	platform_ops.fixups = ibm_currituck_fixups;
+	platform_ops.exit = ibm44x_dbcr_reset;
+	pir_reg = mfspr(SPRN_PIR);
+
+	/* Make sure FDT blob is sane */
+	if (fdt_check_header(_dtb_start) != 0)
+		fatal("Invalid device tree blob\n");
+
+	node = fdt_node_offset_by_prop_value(_dtb_start, -1, "device_type",
+	                                     "cpu", sizeof("cpu"));
+	if (node < 0)
+		fatal("Cannot find cpu node\n");
+	timebase = fdt_getprop(_dtb_start, node, "timebase-frequency", &size);
+	if (timebase && (size == 4))
+		timebase_period_ns = 1000000000 / *timebase;
+
+	fdt_set_boot_cpuid_phys(_dtb_start, pir_reg);
+	fdt_init(_dtb_start);
+
+	serial_console_init();
+}