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, 82 insertions, 0 deletions

diff --git a/drivers/edac/mce_amd.h b/drivers/edac/mce_amd.h
new file mode 100644
index 000000000..4811b18d9
--- /dev/null
+++ b/drivers/edac/mce_amd.h
@@ -0,0 +1,82 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _EDAC_MCE_AMD_H
+#define _EDAC_MCE_AMD_H
+
+#include <linux/notifier.h>
+
+#include <asm/mce.h>
+
+#define EC(x)				((x) & 0xffff)
+
+#define LOW_SYNDROME(x)			(((x) >> 15) & 0xff)
+#define HIGH_SYNDROME(x)		(((x) >> 24) & 0xff)
+
+#define TLB_ERROR(x)			(((x) & 0xFFF0) == 0x0010)
+#define MEM_ERROR(x)			(((x) & 0xFF00) == 0x0100)
+#define BUS_ERROR(x)			(((x) & 0xF800) == 0x0800)
+#define INT_ERROR(x)			(((x) & 0xF4FF) == 0x0400)
+
+#define TT(x)				(((x) >> 2) & 0x3)
+#define TT_MSG(x)			tt_msgs[TT(x)]
+#define II(x)				(((x) >> 2) & 0x3)
+#define II_MSG(x)			ii_msgs[II(x)]
+#define LL(x)				((x) & 0x3)
+#define LL_MSG(x)			ll_msgs[LL(x)]
+#define TO(x)				(((x) >> 8) & 0x1)
+#define TO_MSG(x)			to_msgs[TO(x)]
+#define PP(x)				(((x) >> 9) & 0x3)
+#define PP_MSG(x)			pp_msgs[PP(x)]
+#define UU(x)				(((x) >> 8) & 0x3)
+#define UU_MSG(x)			uu_msgs[UU(x)]
+
+#define R4(x)				(((x) >> 4) & 0xf)
+#define R4_MSG(x)			((R4(x) < 9) ?  rrrr_msgs[R4(x)] : "Wrong R4!")
+
+extern const char * const pp_msgs[];
+
+enum tt_ids {
+	TT_INSTR = 0,
+	TT_DATA,
+	TT_GEN,
+	TT_RESV,
+};
+
+enum ll_ids {
+	LL_RESV = 0,
+	LL_L1,
+	LL_L2,
+	LL_LG,
+};
+
+enum ii_ids {
+	II_MEM = 0,
+	II_RESV,
+	II_IO,
+	II_GEN,
+};
+
+enum rrrr_ids {
+	R4_GEN	= 0,
+	R4_RD,
+	R4_WR,
+	R4_DRD,
+	R4_DWR,
+	R4_IRD,
+	R4_PREF,
+	R4_EVICT,
+	R4_SNOOP,
+};
+
+/*
+ * per-family decoder ops
+ */
+struct amd_decoder_ops {
+	bool (*mc0_mce)(u16, u8);
+	bool (*mc1_mce)(u16, u8);
+	bool (*mc2_mce)(u16, u8);
+};
+
+void amd_register_ecc_decoder(void (*f)(int, struct mce *));
+void amd_unregister_ecc_decoder(void (*f)(int, struct mce *));
+
+#endif /* _EDAC_MCE_AMD_H */