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, 133 insertions, 0 deletions

diff --git a/drivers/firmware/efi/fdtparams.c b/drivers/firmware/efi/fdtparams.c
new file mode 100644
index 000000000..b815d2a75
--- /dev/null
+++ b/drivers/firmware/efi/fdtparams.c
@@ -0,0 +1,133 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#define pr_fmt(fmt) "efi: " fmt
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/efi.h>
+#include <linux/libfdt.h>
+#include <linux/of_fdt.h>
+
+#include <linux/unaligned.h>
+
+enum {
+	SYSTAB,
+	MMBASE,
+	MMSIZE,
+	DCSIZE,
+	DCVERS,
+
+	PARAMCOUNT
+};
+
+static __initconst const char name[][22] = {
+	[SYSTAB] = "System Table         ",
+	[MMBASE] = "MemMap Address       ",
+	[MMSIZE] = "MemMap Size          ",
+	[DCSIZE] = "MemMap Desc. Size    ",
+	[DCVERS] = "MemMap Desc. Version ",
+};
+
+static __initconst const struct {
+	const char	path[17];
+	u8		paravirt;
+	const char	params[PARAMCOUNT][26];
+} dt_params[] = {
+	{
+#ifdef CONFIG_XEN    //  <-------17------>
+		.path = "/hypervisor/uefi",
+		.paravirt = 1,
+		.params = {
+			[SYSTAB] = "xen,uefi-system-table",
+			[MMBASE] = "xen,uefi-mmap-start",
+			[MMSIZE] = "xen,uefi-mmap-size",
+			[DCSIZE] = "xen,uefi-mmap-desc-size",
+			[DCVERS] = "xen,uefi-mmap-desc-ver",
+		}
+	}, {
+#endif
+		.path = "/chosen",
+		.params = {	//  <-----------26----------->
+			[SYSTAB] = "linux,uefi-system-table",
+			[MMBASE] = "linux,uefi-mmap-start",
+			[MMSIZE] = "linux,uefi-mmap-size",
+			[DCSIZE] = "linux,uefi-mmap-desc-size",
+			[DCVERS] = "linux,uefi-mmap-desc-ver",
+		}
+	}
+};
+
+static int __init efi_get_fdt_prop(const void *fdt, int node, const char *pname,
+				   const char *rname, void *var, int size)
+{
+	const void *prop;
+	int len;
+	u64 val;
+
+	prop = fdt_getprop(fdt, node, pname, &len);
+	if (!prop)
+		return 1;
+
+	val = (len == 4) ? (u64)be32_to_cpup(prop) : get_unaligned_be64(prop);
+
+	if (size == 8)
+		*(u64 *)var = val;
+	else
+		*(u32 *)var = (val < U32_MAX) ? val : U32_MAX; // saturate
+
+	if (efi_enabled(EFI_DBG))
+		pr_info("  %s: 0x%0*llx\n", rname, size * 2, val);
+
+	return 0;
+}
+
+u64 __init efi_get_fdt_params(struct efi_memory_map_data *mm)
+{
+	const void *fdt = initial_boot_params;
+	unsigned long systab;
+	int i, j, node;
+	struct {
+		void	*var;
+		int	size;
+	} target[] = {
+		[SYSTAB] = { &systab,		sizeof(systab) },
+		[MMBASE] = { &mm->phys_map,	sizeof(mm->phys_map) },
+		[MMSIZE] = { &mm->size,		sizeof(mm->size) },
+		[DCSIZE] = { &mm->desc_size,	sizeof(mm->desc_size) },
+		[DCVERS] = { &mm->desc_version,	sizeof(mm->desc_version) },
+	};
+
+	BUILD_BUG_ON(ARRAY_SIZE(target) != ARRAY_SIZE(name));
+	BUILD_BUG_ON(ARRAY_SIZE(target) != ARRAY_SIZE(dt_params[0].params));
+
+	if (!fdt)
+		return 0;
+
+	for (i = 0; i < ARRAY_SIZE(dt_params); i++) {
+		node = fdt_path_offset(fdt, dt_params[i].path);
+		if (node < 0)
+			continue;
+
+		if (efi_enabled(EFI_DBG))
+			pr_info("Getting UEFI parameters from %s in DT:\n",
+				dt_params[i].path);
+
+		for (j = 0; j < ARRAY_SIZE(target); j++) {
+			const char *pname = dt_params[i].params[j];
+
+			if (!efi_get_fdt_prop(fdt, node, pname, name[j],
+					      target[j].var, target[j].size))
+				continue;
+			if (!j)
+				goto notfound;
+			pr_err("Can't find property '%s' in DT!\n", pname);
+			return 0;
+		}
+		if (dt_params[i].paravirt)
+			set_bit(EFI_PARAVIRT, &efi.flags);
+		return systab;
+	}
+notfound:
+	pr_info("UEFI not found.\n");
+	return 0;
+}