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, 43 insertions, 0 deletions

diff --git a/lib/crypto/sparc/sha256.h b/lib/crypto/sparc/sha256.h
new file mode 100644
index 000000000..b2f4419ec
--- /dev/null
+++ b/lib/crypto/sparc/sha256.h
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * SHA-256 accelerated using the sparc64 sha256 opcodes
+ *
+ * Copyright (c) Jean-Luc Cooke <jlcooke@certainkey.com>
+ * Copyright (c) Andrew McDonald <andrew@mcdonald.org.uk>
+ * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
+ * SHA224 Support Copyright 2007 Intel Corporation <jonathan.lynch@intel.com>
+ */
+
+#include <asm/elf.h>
+#include <asm/opcodes.h>
+#include <asm/pstate.h>
+
+static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_sha256_opcodes);
+
+asmlinkage void sha256_sparc64_transform(struct sha256_block_state *state,
+					 const u8 *data, size_t nblocks);
+
+static void sha256_blocks(struct sha256_block_state *state,
+			  const u8 *data, size_t nblocks)
+{
+	if (static_branch_likely(&have_sha256_opcodes))
+		sha256_sparc64_transform(state, data, nblocks);
+	else
+		sha256_blocks_generic(state, data, nblocks);
+}
+
+#define sha256_mod_init_arch sha256_mod_init_arch
+static void sha256_mod_init_arch(void)
+{
+	unsigned long cfr;
+
+	if (!(sparc64_elf_hwcap & HWCAP_SPARC_CRYPTO))
+		return;
+
+	__asm__ __volatile__("rd %%asr26, %0" : "=r" (cfr));
+	if (!(cfr & CFR_SHA256))
+		return;
+
+	static_branch_enable(&have_sha256_opcodes);
+	pr_info("Using sparc64 sha256 opcode optimized SHA-256/SHA-224 implementation\n");
+}