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, 116 insertions, 0 deletions

diff --git a/drivers/firmware/efi/tpm.c b/drivers/firmware/efi/tpm.c
new file mode 100644
index 000000000..cdd431027
--- /dev/null
+++ b/drivers/firmware/efi/tpm.c
@@ -0,0 +1,116 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2017 Google, Inc.
+ *     Thiebaud Weksteen <tweek@google.com>
+ */
+
+#define TPM_MEMREMAP(start, size) early_memremap(start, size)
+#define TPM_MEMUNMAP(start, size) early_memunmap(start, size)
+
+#include <asm/early_ioremap.h>
+#include <linux/efi.h>
+#include <linux/init.h>
+#include <linux/memblock.h>
+#include <linux/tpm_eventlog.h>
+
+int efi_tpm_final_log_size;
+EXPORT_SYMBOL(efi_tpm_final_log_size);
+
+static int __init tpm2_calc_event_log_size(void *data, int count, void *size_info)
+{
+	struct tcg_pcr_event2_head *header;
+	u32 event_size, size = 0;
+
+	while (count > 0) {
+		header = data + size;
+		event_size = __calc_tpm2_event_size(header, size_info, true);
+		if (event_size == 0)
+			return -1;
+		size += event_size;
+		count--;
+	}
+
+	return size;
+}
+
+/*
+ * Reserve the memory associated with the TPM Event Log configuration table.
+ */
+int __init efi_tpm_eventlog_init(void)
+{
+	struct linux_efi_tpm_eventlog *log_tbl;
+	struct efi_tcg2_final_events_table *final_tbl;
+	unsigned int tbl_size;
+	int final_tbl_size;
+	int ret = 0;
+
+	if (efi.tpm_log == EFI_INVALID_TABLE_ADDR) {
+		/*
+		 * We can't calculate the size of the final events without the
+		 * first entry in the TPM log, so bail here.
+		 */
+		return 0;
+	}
+
+	log_tbl = early_memremap(efi.tpm_log, sizeof(*log_tbl));
+	if (!log_tbl) {
+		pr_err("Failed to map TPM Event Log table @ 0x%lx\n",
+		       efi.tpm_log);
+		efi.tpm_log = EFI_INVALID_TABLE_ADDR;
+		return -ENOMEM;
+	}
+
+	tbl_size = sizeof(*log_tbl) + log_tbl->size;
+	if (memblock_reserve(efi.tpm_log, tbl_size)) {
+		pr_err("TPM Event Log memblock reserve fails (0x%lx, 0x%x)\n",
+		       efi.tpm_log, tbl_size);
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	if (efi.tpm_final_log == EFI_INVALID_TABLE_ADDR) {
+		pr_info("TPM Final Events table not present\n");
+		goto out;
+	} else if (log_tbl->version != EFI_TCG2_EVENT_LOG_FORMAT_TCG_2) {
+		pr_warn(FW_BUG "TPM Final Events table invalid\n");
+		goto out;
+	}
+
+	final_tbl = early_memremap(efi.tpm_final_log, sizeof(*final_tbl));
+
+	if (!final_tbl) {
+		pr_err("Failed to map TPM Final Event Log table @ 0x%lx\n",
+		       efi.tpm_final_log);
+		efi.tpm_final_log = EFI_INVALID_TABLE_ADDR;
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	final_tbl_size = 0;
+	if (final_tbl->nr_events != 0) {
+		void *events = (void *)efi.tpm_final_log
+				+ sizeof(final_tbl->version)
+				+ sizeof(final_tbl->nr_events);
+
+		final_tbl_size = tpm2_calc_event_log_size(events,
+							  final_tbl->nr_events,
+							  log_tbl->log);
+	}
+
+	if (final_tbl_size < 0) {
+		pr_err(FW_BUG "Failed to parse event in TPM Final Events Log\n");
+		ret = -EINVAL;
+		goto out_calc;
+	}
+
+	memblock_reserve(efi.tpm_final_log,
+			 final_tbl_size + sizeof(*final_tbl));
+	efi_tpm_final_log_size = final_tbl_size;
+
+out_calc:
+	early_memunmap(final_tbl, sizeof(*final_tbl));
+out:
+	early_memunmap(log_tbl, sizeof(*log_tbl));
+	return ret;
+}
+