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, 109 insertions, 0 deletions

diff --git a/lib/crypto/powerpc/gf128hash.h b/lib/crypto/powerpc/gf128hash.h
new file mode 100644
index 000000000..629cd325d
--- /dev/null
+++ b/lib/crypto/powerpc/gf128hash.h
@@ -0,0 +1,109 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * GHASH routines supporting VMX instructions on the Power 8
+ *
+ * Copyright (C) 2015, 2019 International Business Machines Inc.
+ * Copyright (C) 2014 - 2018 Linaro Ltd.
+ * Copyright 2026 Google LLC
+ */
+
+#include <asm/simd.h>
+#include <asm/switch_to.h>
+#include <linux/cpufeature.h>
+#include <linux/jump_label.h>
+#include <linux/preempt.h>
+#include <linux/uaccess.h>
+
+static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_vec_crypto);
+
+void gcm_init_p8(u64 htable[4][2], const u8 h[16]);
+void gcm_gmult_p8(u8 Xi[16], const u64 htable[4][2]);
+void gcm_ghash_p8(u8 Xi[16], const u64 htable[4][2], const u8 *in, size_t len);
+
+#define ghash_preparekey_arch ghash_preparekey_arch
+static void ghash_preparekey_arch(struct ghash_key *key,
+				  const u8 raw_key[GHASH_BLOCK_SIZE])
+{
+	ghash_key_to_polyval(raw_key, &key->h);
+
+	if (static_branch_likely(&have_vec_crypto) && likely(may_use_simd())) {
+		preempt_disable();
+		pagefault_disable();
+		enable_kernel_vsx();
+		gcm_init_p8(key->htable, raw_key);
+		disable_kernel_vsx();
+		pagefault_enable();
+		preempt_enable();
+	} else {
+		/* This reproduces gcm_init_p8() on both LE and BE systems. */
+		key->htable[0][0] = 0;
+		key->htable[0][1] = 0xc200000000000000;
+
+		key->htable[1][0] = 0;
+		key->htable[1][1] = le64_to_cpu(key->h.lo);
+
+		key->htable[2][0] = le64_to_cpu(key->h.lo);
+		key->htable[2][1] = le64_to_cpu(key->h.hi);
+
+		key->htable[3][0] = le64_to_cpu(key->h.hi);
+		key->htable[3][1] = 0;
+	}
+}
+
+#define ghash_mul_arch ghash_mul_arch
+static void ghash_mul_arch(struct polyval_elem *acc,
+			   const struct ghash_key *key)
+{
+	if (static_branch_likely(&have_vec_crypto) && likely(may_use_simd())) {
+		u8 ghash_acc[GHASH_BLOCK_SIZE];
+
+		polyval_acc_to_ghash(acc, ghash_acc);
+
+		preempt_disable();
+		pagefault_disable();
+		enable_kernel_vsx();
+		gcm_gmult_p8(ghash_acc, key->htable);
+		disable_kernel_vsx();
+		pagefault_enable();
+		preempt_enable();
+
+		ghash_acc_to_polyval(ghash_acc, acc);
+		memzero_explicit(ghash_acc, sizeof(ghash_acc));
+	} else {
+		polyval_mul_generic(acc, &key->h);
+	}
+}
+
+#define ghash_blocks_arch ghash_blocks_arch
+static void ghash_blocks_arch(struct polyval_elem *acc,
+			      const struct ghash_key *key,
+			      const u8 *data, size_t nblocks)
+{
+	if (static_branch_likely(&have_vec_crypto) && likely(may_use_simd())) {
+		u8 ghash_acc[GHASH_BLOCK_SIZE];
+
+		polyval_acc_to_ghash(acc, ghash_acc);
+
+		preempt_disable();
+		pagefault_disable();
+		enable_kernel_vsx();
+		gcm_ghash_p8(ghash_acc, key->htable, data,
+			     nblocks * GHASH_BLOCK_SIZE);
+		disable_kernel_vsx();
+		pagefault_enable();
+		preempt_enable();
+
+		ghash_acc_to_polyval(ghash_acc, acc);
+		memzero_explicit(ghash_acc, sizeof(ghash_acc));
+	} else {
+		ghash_blocks_generic(acc, &key->h, data, nblocks);
+	}
+}
+
+#define gf128hash_mod_init_arch gf128hash_mod_init_arch
+static void gf128hash_mod_init_arch(void)
+{
+	if (cpu_has_feature(CPU_FTR_ARCH_207S) &&
+	    (cur_cpu_spec->cpu_user_features2 & PPC_FEATURE2_VEC_CRYPTO))
+		static_branch_enable(&have_vec_crypto);
+}