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, 88 insertions, 0 deletions

diff --git a/lib/crypto/arm64/chacha.h b/lib/crypto/arm64/chacha.h
new file mode 100644
index 000000000..c6f8ddf98
--- /dev/null
+++ b/lib/crypto/arm64/chacha.h
@@ -0,0 +1,88 @@
+/*
+ * ChaCha and HChaCha functions (ARM64 optimized)
+ *
+ * Copyright (C) 2016 - 2017 Linaro, Ltd. <ard.biesheuvel@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Based on:
+ * ChaCha20 256-bit cipher algorithm, RFC7539, SIMD glue code
+ *
+ * Copyright (C) 2015 Martin Willi
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <crypto/internal/simd.h>
+#include <linux/jump_label.h>
+#include <linux/kernel.h>
+
+#include <asm/hwcap.h>
+#include <asm/simd.h>
+
+asmlinkage void chacha_block_xor_neon(const struct chacha_state *state,
+				      u8 *dst, const u8 *src, int nrounds);
+asmlinkage void chacha_4block_xor_neon(const struct chacha_state *state,
+				       u8 *dst, const u8 *src,
+				       int nrounds, int bytes);
+asmlinkage void hchacha_block_neon(const struct chacha_state *state,
+				   u32 out[HCHACHA_OUT_WORDS], int nrounds);
+
+static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_neon);
+
+static void chacha_doneon(struct chacha_state *state, u8 *dst, const u8 *src,
+			  unsigned int bytes, int nrounds)
+{
+	while (bytes) {
+		int l = min(bytes, CHACHA_BLOCK_SIZE * 5);
+
+		if (l <= CHACHA_BLOCK_SIZE) {
+			u8 buf[CHACHA_BLOCK_SIZE];
+
+			memcpy(buf, src, l);
+			chacha_block_xor_neon(state, buf, buf, nrounds);
+			memcpy(dst, buf, l);
+			state->x[12] += 1;
+			break;
+		}
+		chacha_4block_xor_neon(state, dst, src, nrounds, l);
+		bytes -= l;
+		src += l;
+		dst += l;
+		state->x[12] += DIV_ROUND_UP(l, CHACHA_BLOCK_SIZE);
+	}
+}
+
+static void hchacha_block_arch(const struct chacha_state *state,
+			       u32 out[HCHACHA_OUT_WORDS], int nrounds)
+{
+	if (!static_branch_likely(&have_neon) || !crypto_simd_usable()) {
+		hchacha_block_generic(state, out, nrounds);
+	} else {
+		scoped_ksimd()
+			hchacha_block_neon(state, out, nrounds);
+	}
+}
+
+static void chacha_crypt_arch(struct chacha_state *state, u8 *dst,
+			      const u8 *src, unsigned int bytes, int nrounds)
+{
+	if (!static_branch_likely(&have_neon) || bytes <= CHACHA_BLOCK_SIZE ||
+	    !crypto_simd_usable())
+		return chacha_crypt_generic(state, dst, src, bytes, nrounds);
+
+	scoped_ksimd()
+		chacha_doneon(state, dst, src, bytes, nrounds);
+}
+
+#define chacha_mod_init_arch chacha_mod_init_arch
+static void chacha_mod_init_arch(void)
+{
+	if (cpu_have_named_feature(ASIMD))
+		static_branch_enable(&have_neon);
+}