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, 247 insertions, 0 deletions

diff --git a/drivers/soc/apple/rtkit-crashlog.c b/drivers/soc/apple/rtkit-crashlog.c
new file mode 100644
index 000000000..8319e3651
--- /dev/null
+++ b/drivers/soc/apple/rtkit-crashlog.c
@@ -0,0 +1,247 @@
+// SPDX-License-Identifier: GPL-2.0-only OR MIT
+/*
+ * Apple RTKit IPC library
+ * Copyright (C) The Asahi Linux Contributors
+ */
+#include "rtkit-internal.h"
+
+#define FOURCC(a, b, c, d) \
+	(((u32)(a) << 24) | ((u32)(b) << 16) | ((u32)(c) << 8) | ((u32)(d)))
+
+#define APPLE_RTKIT_CRASHLOG_HEADER FOURCC('C', 'L', 'H', 'E')
+#define APPLE_RTKIT_CRASHLOG_STR FOURCC('C', 's', 't', 'r')
+#define APPLE_RTKIT_CRASHLOG_VERSION FOURCC('C', 'v', 'e', 'r')
+#define APPLE_RTKIT_CRASHLOG_MBOX FOURCC('C', 'm', 'b', 'x')
+#define APPLE_RTKIT_CRASHLOG_TIME FOURCC('C', 't', 'i', 'm')
+#define APPLE_RTKIT_CRASHLOG_REGS FOURCC('C', 'r', 'g', '8')
+
+/* For COMPILE_TEST on non-ARM64 architectures */
+#ifndef PSR_MODE_EL0t
+#define PSR_MODE_EL0t	0x00000000
+#define PSR_MODE_EL1t	0x00000004
+#define PSR_MODE_EL1h	0x00000005
+#define PSR_MODE_EL2t	0x00000008
+#define PSR_MODE_EL2h	0x00000009
+#define PSR_MODE_MASK	0x0000000f
+#endif
+
+struct apple_rtkit_crashlog_header {
+	u32 fourcc;
+	u32 version;
+	u32 size;
+	u32 flags;
+	u8 _unk[16];
+};
+static_assert(sizeof(struct apple_rtkit_crashlog_header) == 0x20);
+
+struct apple_rtkit_crashlog_mbox_entry {
+	u64 msg0;
+	u64 msg1;
+	u32 timestamp;
+	u8 _unk[4];
+};
+static_assert(sizeof(struct apple_rtkit_crashlog_mbox_entry) == 0x18);
+
+struct apple_rtkit_crashlog_regs {
+	u32 unk_0;
+	u32 unk_4;
+	u64 regs[31];
+	u64 sp;
+	u64 pc;
+	u64 psr;
+	u64 cpacr;
+	u64 fpsr;
+	u64 fpcr;
+	u64 unk[64];
+	u64 far;
+	u64 unk_X;
+	u64 esr;
+	u64 unk_Z;
+} __packed;
+static_assert(sizeof(struct apple_rtkit_crashlog_regs) == 0x350);
+
+static void apple_rtkit_crashlog_dump_str(struct apple_rtkit *rtk, u8 *bfr,
+					  size_t size)
+{
+	u32 idx;
+	u8 *ptr, *end;
+
+	memcpy(&idx, bfr, 4);
+
+	ptr = bfr + 4;
+	end = bfr + size;
+	while (ptr < end) {
+		u8 *newline = memchr(ptr, '\n', end - ptr);
+
+		if (newline) {
+			u8 tmp = *newline;
+			*newline = '\0';
+			dev_warn(rtk->dev, "RTKit: Message (id=%x): %s\n", idx,
+				 ptr);
+			*newline = tmp;
+			ptr = newline + 1;
+		} else {
+			dev_warn(rtk->dev, "RTKit: Message (id=%x): %s", idx,
+				 ptr);
+			break;
+		}
+	}
+}
+
+static void apple_rtkit_crashlog_dump_version(struct apple_rtkit *rtk, u8 *bfr,
+					      size_t size)
+{
+	dev_warn(rtk->dev, "RTKit: Version: %s", bfr + 16);
+}
+
+static void apple_rtkit_crashlog_dump_time(struct apple_rtkit *rtk, u8 *bfr,
+					   size_t size)
+{
+	u64 crash_time;
+
+	memcpy(&crash_time, bfr, 8);
+	dev_warn(rtk->dev, "RTKit: Crash time: %lld", crash_time);
+}
+
+static void apple_rtkit_crashlog_dump_mailbox(struct apple_rtkit *rtk, u8 *bfr,
+					      size_t size)
+{
+	u32 type, index, i;
+	size_t n_messages;
+	struct apple_rtkit_crashlog_mbox_entry entry;
+
+	memcpy(&type, bfr + 16, 4);
+	memcpy(&index, bfr + 24, 4);
+	n_messages = (size - 28) / sizeof(entry);
+
+	dev_warn(rtk->dev, "RTKit: Mailbox history (type = %d, index = %d)",
+		 type, index);
+	for (i = 0; i < n_messages; ++i) {
+		memcpy(&entry, bfr + 28 + i * sizeof(entry), sizeof(entry));
+		dev_warn(rtk->dev, "RTKit:  #%03d@%08x: %016llx %016llx", i,
+			 entry.timestamp, entry.msg0, entry.msg1);
+	}
+}
+
+static void apple_rtkit_crashlog_dump_regs(struct apple_rtkit *rtk, u8 *bfr,
+					   size_t size)
+{
+	struct apple_rtkit_crashlog_regs *regs;
+	const char *el;
+	int i;
+
+	if (size < sizeof(*regs)) {
+		dev_warn(rtk->dev, "RTKit: Regs section too small: 0x%zx", size);
+		return;
+	}
+
+	regs = (struct apple_rtkit_crashlog_regs *)bfr;
+
+	switch (regs->psr & PSR_MODE_MASK) {
+	case PSR_MODE_EL0t:
+		el = "EL0t";
+		break;
+	case PSR_MODE_EL1t:
+		el = "EL1t";
+		break;
+	case PSR_MODE_EL1h:
+		el = "EL1h";
+		break;
+	case PSR_MODE_EL2t:
+		el = "EL2t";
+		break;
+	case PSR_MODE_EL2h:
+		el = "EL2h";
+		break;
+	default:
+		el = "unknown";
+		break;
+	}
+
+	dev_warn(rtk->dev, "RTKit: Exception dump:");
+	dev_warn(rtk->dev, "  == Exception taken from %s ==", el);
+	dev_warn(rtk->dev, "  PSR    = 0x%llx", regs->psr);
+	dev_warn(rtk->dev, "  PC     = 0x%llx\n", regs->pc);
+	dev_warn(rtk->dev, "  ESR    = 0x%llx\n", regs->esr);
+	dev_warn(rtk->dev, "  FAR    = 0x%llx\n", regs->far);
+	dev_warn(rtk->dev, "  SP     = 0x%llx\n", regs->sp);
+	dev_warn(rtk->dev, "\n");
+
+	for (i = 0; i < 31; i += 4) {
+		if (i < 28)
+			dev_warn(rtk->dev,
+					 "  x%02d-x%02d = %016llx %016llx %016llx %016llx\n",
+					 i, i + 3,
+					 regs->regs[i], regs->regs[i + 1],
+					 regs->regs[i + 2], regs->regs[i + 3]);
+		else
+			dev_warn(rtk->dev,
+					 "  x%02d-x%02d = %016llx %016llx %016llx\n", i, i + 3,
+					 regs->regs[i], regs->regs[i + 1], regs->regs[i + 2]);
+	}
+
+	dev_warn(rtk->dev, "\n");
+}
+
+void apple_rtkit_crashlog_dump(struct apple_rtkit *rtk, u8 *bfr, size_t size)
+{
+	size_t offset;
+	u32 section_fourcc, section_size;
+	struct apple_rtkit_crashlog_header header;
+
+	memcpy(&header, bfr, sizeof(header));
+	if (header.fourcc != APPLE_RTKIT_CRASHLOG_HEADER) {
+		dev_warn(rtk->dev, "RTKit: Expected crashlog header but got %x",
+			 header.fourcc);
+		return;
+	}
+
+	if (header.size > size) {
+		dev_warn(rtk->dev, "RTKit: Crashlog size (%x) is too large",
+			 header.size);
+		return;
+	}
+
+	size = header.size;
+	offset = sizeof(header);
+
+	while (offset < size) {
+		memcpy(&section_fourcc, bfr + offset, 4);
+		memcpy(&section_size, bfr + offset + 12, 4);
+
+		switch (section_fourcc) {
+		case APPLE_RTKIT_CRASHLOG_HEADER:
+			dev_dbg(rtk->dev, "RTKit: End of crashlog reached");
+			return;
+		case APPLE_RTKIT_CRASHLOG_STR:
+			apple_rtkit_crashlog_dump_str(rtk, bfr + offset + 16,
+						      section_size);
+			break;
+		case APPLE_RTKIT_CRASHLOG_VERSION:
+			apple_rtkit_crashlog_dump_version(
+				rtk, bfr + offset + 16, section_size);
+			break;
+		case APPLE_RTKIT_CRASHLOG_MBOX:
+			apple_rtkit_crashlog_dump_mailbox(
+				rtk, bfr + offset + 16, section_size);
+			break;
+		case APPLE_RTKIT_CRASHLOG_TIME:
+			apple_rtkit_crashlog_dump_time(rtk, bfr + offset + 16,
+						       section_size);
+			break;
+		case APPLE_RTKIT_CRASHLOG_REGS:
+			apple_rtkit_crashlog_dump_regs(rtk, bfr + offset + 16,
+						       section_size);
+			break;
+		default:
+			dev_warn(rtk->dev,
+				 "RTKit: Unknown crashlog section: %x",
+				 section_fourcc);
+		}
+
+		offset += section_size;
+	}
+
+	dev_warn(rtk->dev,
+		 "RTKit: End of crashlog reached but no footer present");
+}