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, 106 insertions, 0 deletions

diff --git a/lib/crypto/s390/aes.h b/lib/crypto/s390/aes.h
new file mode 100644
index 000000000..5466f6ecb
--- /dev/null
+++ b/lib/crypto/s390/aes.h
@@ -0,0 +1,106 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * AES optimized using the CP Assist for Cryptographic Functions (CPACF)
+ *
+ * Copyright 2026 Google LLC
+ */
+#include <asm/cpacf.h>
+#include <linux/cpufeature.h>
+
+static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_cpacf_aes128);
+static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_cpacf_aes192);
+static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_cpacf_aes256);
+
+/*
+ * When the CPU supports CPACF AES for the requested key length, we need only
+ * save a copy of the raw AES key, as that's what the CPACF instructions need.
+ *
+ * When unsupported, fall back to the generic key expansion and en/decryption.
+ */
+static void aes_preparekey_arch(union aes_enckey_arch *k,
+				union aes_invkey_arch *inv_k,
+				const u8 *in_key, int key_len, int nrounds)
+{
+	if (key_len == AES_KEYSIZE_128) {
+		if (static_branch_likely(&have_cpacf_aes128)) {
+			memcpy(k->raw_key, in_key, AES_KEYSIZE_128);
+			return;
+		}
+	} else if (key_len == AES_KEYSIZE_192) {
+		if (static_branch_likely(&have_cpacf_aes192)) {
+			memcpy(k->raw_key, in_key, AES_KEYSIZE_192);
+			return;
+		}
+	} else {
+		if (static_branch_likely(&have_cpacf_aes256)) {
+			memcpy(k->raw_key, in_key, AES_KEYSIZE_256);
+			return;
+		}
+	}
+	aes_expandkey_generic(k->rndkeys, inv_k ? inv_k->inv_rndkeys : NULL,
+			      in_key, key_len);
+}
+
+static inline bool aes_crypt_s390(const struct aes_enckey *key,
+				  u8 out[AES_BLOCK_SIZE],
+				  const u8 in[AES_BLOCK_SIZE], int decrypt)
+{
+	if (key->len == AES_KEYSIZE_128) {
+		if (static_branch_likely(&have_cpacf_aes128)) {
+			cpacf_km(CPACF_KM_AES_128 | decrypt,
+				 (void *)key->k.raw_key, out, in,
+				 AES_BLOCK_SIZE);
+			return true;
+		}
+	} else if (key->len == AES_KEYSIZE_192) {
+		if (static_branch_likely(&have_cpacf_aes192)) {
+			cpacf_km(CPACF_KM_AES_192 | decrypt,
+				 (void *)key->k.raw_key, out, in,
+				 AES_BLOCK_SIZE);
+			return true;
+		}
+	} else {
+		if (static_branch_likely(&have_cpacf_aes256)) {
+			cpacf_km(CPACF_KM_AES_256 | decrypt,
+				 (void *)key->k.raw_key, out, in,
+				 AES_BLOCK_SIZE);
+			return true;
+		}
+	}
+	return false;
+}
+
+static void aes_encrypt_arch(const struct aes_enckey *key,
+			     u8 out[AES_BLOCK_SIZE],
+			     const u8 in[AES_BLOCK_SIZE])
+{
+	if (likely(aes_crypt_s390(key, out, in, 0)))
+		return;
+	aes_encrypt_generic(key->k.rndkeys, key->nrounds, out, in);
+}
+
+static void aes_decrypt_arch(const struct aes_key *key,
+			     u8 out[AES_BLOCK_SIZE],
+			     const u8 in[AES_BLOCK_SIZE])
+{
+	if (likely(aes_crypt_s390((const struct aes_enckey *)key, out, in,
+				  CPACF_DECRYPT)))
+		return;
+	aes_decrypt_generic(key->inv_k.inv_rndkeys, key->nrounds, out, in);
+}
+
+#define aes_mod_init_arch aes_mod_init_arch
+static void aes_mod_init_arch(void)
+{
+	if (cpu_have_feature(S390_CPU_FEATURE_MSA)) {
+		cpacf_mask_t km_functions;
+
+		cpacf_query(CPACF_KM, &km_functions);
+		if (cpacf_test_func(&km_functions, CPACF_KM_AES_128))
+			static_branch_enable(&have_cpacf_aes128);
+		if (cpacf_test_func(&km_functions, CPACF_KM_AES_192))
+			static_branch_enable(&have_cpacf_aes192);
+		if (cpacf_test_func(&km_functions, CPACF_KM_AES_256))
+			static_branch_enable(&have_cpacf_aes256);
+	}
+}