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, 214 insertions, 0 deletions

diff --git a/tools/firewire/decode-fcp.c b/tools/firewire/decode-fcp.c
new file mode 100644
index 000000000..f115a3be8
--- /dev/null
+++ b/tools/firewire/decode-fcp.c
@@ -0,0 +1,214 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/firewire-constants.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "list.h"
+#include "nosy-dump.h"
+
+#define CSR_FCP_COMMAND			0xfffff0000b00ull
+#define CSR_FCP_RESPONSE		0xfffff0000d00ull
+
+static const char * const ctype_names[] = {
+	[0x0] = "control",		[0x8] = "not implemented",
+	[0x1] = "status",		[0x9] = "accepted",
+	[0x2] = "specific inquiry",	[0xa] = "rejected",
+	[0x3] = "notify",		[0xb] = "in transition",
+	[0x4] = "general inquiry",	[0xc] = "stable",
+	[0x5] = "(reserved 0x05)",	[0xd] = "changed",
+	[0x6] = "(reserved 0x06)",	[0xe] = "(reserved 0x0e)",
+	[0x7] = "(reserved 0x07)",	[0xf] = "interim",
+};
+
+static const char * const subunit_type_names[] = {
+	[0x00] = "monitor",		[0x10] = "(reserved 0x10)",
+	[0x01] = "audio",		[0x11] = "(reserved 0x11)",
+	[0x02] = "printer",		[0x12] = "(reserved 0x12)",
+	[0x03] = "disc",		[0x13] = "(reserved 0x13)",
+	[0x04] = "tape recorder/player",[0x14] = "(reserved 0x14)",
+	[0x05] = "tuner",		[0x15] = "(reserved 0x15)",
+	[0x06] = "ca",			[0x16] = "(reserved 0x16)",
+	[0x07] = "camera",		[0x17] = "(reserved 0x17)",
+	[0x08] = "(reserved 0x08)",	[0x18] = "(reserved 0x18)",
+	[0x09] = "panel",		[0x19] = "(reserved 0x19)",
+	[0x0a] = "bulletin board",	[0x1a] = "(reserved 0x1a)",
+	[0x0b] = "camera storage",	[0x1b] = "(reserved 0x1b)",
+	[0x0c] = "(reserved 0x0c)",	[0x1c] = "vendor unique",
+	[0x0d] = "(reserved 0x0d)",	[0x1d] = "all subunit types",
+	[0x0e] = "(reserved 0x0e)",	[0x1e] = "subunit_type extended to next byte",
+	[0x0f] = "(reserved 0x0f)",	[0x1f] = "unit",
+};
+
+struct avc_enum {
+	int value;
+	const char *name;
+};
+
+struct avc_field {
+	const char *name;	/* Short name for field. */
+	int offset;		/* Location of field, specified in bits; */
+				/* negative means from end of packet.    */
+	int width;		/* Width of field, 0 means use data_length. */
+	struct avc_enum *names;
+};
+
+struct avc_opcode_info {
+	const char *name;
+	struct avc_field fields[8];
+};
+
+struct avc_enum power_field_names[] = {
+	{ 0x70, "on" },
+	{ 0x60, "off" },
+	{ }
+};
+
+static const struct avc_opcode_info opcode_info[256] = {
+
+	/* TA Document 1999026 */
+	/* AV/C Digital Interface Command Set General Specification 4.0 */
+	[0xb2] = { "power", {
+			{ "state", 0, 8, power_field_names }
+		}
+	},
+	[0x30] = { "unit info", {
+			{ "foo", 0, 8 },
+			{ "unit_type", 8, 5 },
+			{ "unit", 13, 3 },
+			{ "company id", 16, 24 },
+		}
+	},
+	[0x31] = { "subunit info" },
+	[0x01] = { "reserve" },
+	[0xb0] = { "version" },
+	[0x00] = { "vendor dependent" },
+	[0x02] = { "plug info" },
+	[0x12] = { "channel usage" },
+	[0x24] = { "connect" },
+	[0x20] = { "connect av" },
+	[0x22] = { "connections" },
+	[0x11] = { "digital input" },
+	[0x10] = { "digital output" },
+	[0x25] = { "disconnect" },
+	[0x21] = { "disconnect av" },
+	[0x19] = { "input plug signal format" },
+	[0x18] = { "output plug signal format" },
+	[0x1f] = { "general bus setup" },
+
+	/* TA Document 1999025 */
+	/* AV/C Descriptor Mechanism Specification Version 1.0 */
+	[0x0c] = { "create descriptor" },
+	[0x08] = { "open descriptor" },
+	[0x09] = { "read descriptor" },
+	[0x0a] = { "write descriptor" },
+	[0x05] = { "open info block" },
+	[0x06] = { "read info block" },
+	[0x07] = { "write info block" },
+	[0x0b] = { "search descriptor" },
+	[0x0d] = { "object number select" },
+
+	/* TA Document 1999015 */
+	/* AV/C Command Set for Rate Control of Isochronous Data Flow 1.0 */
+	[0xb3] = { "rate", {
+			{ "subfunction", 0, 8 },
+			{ "result", 8, 8 },
+			{ "plug_type", 16, 8 },
+			{ "plug_id", 16, 8 },
+		}
+	},
+
+	/* TA Document 1999008 */
+	/* AV/C Audio Subunit Specification 1.0 */
+	[0xb8] = { "function block" },
+
+	/* TA Document 2001001 */
+	/* AV/C Panel Subunit Specification 1.1 */
+	[0x7d] = { "gui update" },
+	[0x7e] = { "push gui data" },
+	[0x7f] = { "user action" },
+	[0x7c] = { "pass through" },
+
+	/* */
+	[0x26] = { "asynchronous connection" },
+};
+
+struct avc_frame {
+	uint32_t operand0:8;
+	uint32_t opcode:8;
+	uint32_t subunit_id:3;
+	uint32_t subunit_type:5;
+	uint32_t ctype:4;
+	uint32_t cts:4;
+};
+
+static void
+decode_avc(struct link_transaction *t)
+{
+	struct avc_frame *frame =
+	    (struct avc_frame *) t->request->packet.write_block.data;
+	const struct avc_opcode_info *info;
+	const char *name;
+	char buffer[32];
+	int i;
+
+	info = &opcode_info[frame->opcode];
+	if (info->name == NULL) {
+		snprintf(buffer, sizeof(buffer),
+			 "(unknown opcode 0x%02x)", frame->opcode);
+		name = buffer;
+	} else {
+		name = info->name;
+	}
+
+	printf("av/c %s, subunit_type=%s, subunit_id=%u, opcode=%s",
+	    ctype_names[frame->ctype], subunit_type_names[frame->subunit_type],
+	    frame->subunit_id, name);
+
+	for (i = 0; info->fields[i].name != NULL; i++)
+		printf(", %s", info->fields[i].name);
+
+	printf("\n");
+}
+
+int
+decode_fcp(struct link_transaction *t)
+{
+	struct avc_frame *frame =
+	    (struct avc_frame *) t->request->packet.write_block.data;
+	unsigned long long offset =
+	    ((unsigned long long) t->request->packet.common.offset_high << 32) |
+	    t->request->packet.common.offset_low;
+
+	if (t->request->packet.common.tcode != TCODE_WRITE_BLOCK_REQUEST)
+		return 0;
+
+	if (offset == CSR_FCP_COMMAND || offset == CSR_FCP_RESPONSE) {
+		switch (frame->cts) {
+		case 0x00:
+			decode_avc(t);
+			break;
+		case 0x01:
+			printf("cal fcp frame (cts=0x01)\n");
+			break;
+		case 0x02:
+			printf("ehs fcp frame (cts=0x02)\n");
+			break;
+		case 0x03:
+			printf("havi fcp frame (cts=0x03)\n");
+			break;
+		case 0x0e:
+			printf("vendor specific fcp frame (cts=0x0e)\n");
+			break;
+		case 0x0f:
+			printf("extended cts\n");
+			break;
+		default:
+			printf("reserved fcp frame (ctx=0x%02x)\n", frame->cts);
+			break;
+		}
+		return 1;
+	}
+
+	return 0;
+}
+