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, 151 insertions, 0 deletions

diff --git a/lib/crypto/s390/sha3.h b/lib/crypto/s390/sha3.h
new file mode 100644
index 000000000..854714047
--- /dev/null
+++ b/lib/crypto/s390/sha3.h
@@ -0,0 +1,151 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * SHA-3 optimized using the CP Assist for Cryptographic Functions (CPACF)
+ *
+ * Copyright 2025 Google LLC
+ */
+#include <asm/cpacf.h>
+#include <linux/cpufeature.h>
+
+static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_sha3);
+static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_sha3_init_optim);
+
+static void sha3_absorb_blocks(struct sha3_state *state, const u8 *data,
+			       size_t nblocks, size_t block_size)
+{
+	if (static_branch_likely(&have_sha3)) {
+		/*
+		 * Note that KIMD assumes little-endian order of the state
+		 * words.  sha3_state already uses that order, though, so
+		 * there's no need for a byteswap.
+		 */
+		switch (block_size) {
+		case SHA3_224_BLOCK_SIZE:
+			cpacf_kimd(CPACF_KIMD_SHA3_224, state,
+				   data, nblocks * block_size);
+			return;
+		case SHA3_256_BLOCK_SIZE:
+			/*
+			 * This case handles both SHA3-256 and SHAKE256, since
+			 * they have the same block size.
+			 */
+			cpacf_kimd(CPACF_KIMD_SHA3_256, state,
+				   data, nblocks * block_size);
+			return;
+		case SHA3_384_BLOCK_SIZE:
+			cpacf_kimd(CPACF_KIMD_SHA3_384, state,
+				   data, nblocks * block_size);
+			return;
+		case SHA3_512_BLOCK_SIZE:
+			cpacf_kimd(CPACF_KIMD_SHA3_512, state,
+				   data, nblocks * block_size);
+			return;
+		}
+	}
+	sha3_absorb_blocks_generic(state, data, nblocks, block_size);
+}
+
+static void sha3_keccakf(struct sha3_state *state)
+{
+	if (static_branch_likely(&have_sha3)) {
+		/*
+		 * Passing zeroes into any of CPACF_KIMD_SHA3_* gives the plain
+		 * Keccak-f permutation, which is what we want here.  Use
+		 * SHA3-512 since it has the smallest block size.
+		 */
+		static const u8 zeroes[SHA3_512_BLOCK_SIZE];
+
+		cpacf_kimd(CPACF_KIMD_SHA3_512, state, zeroes, sizeof(zeroes));
+	} else {
+		sha3_keccakf_generic(state);
+	}
+}
+
+static inline bool s390_sha3(int func, const u8 *in, size_t in_len,
+			     u8 *out, size_t out_len)
+{
+	struct sha3_state state;
+
+	if (!static_branch_likely(&have_sha3))
+		return false;
+
+	if (static_branch_likely(&have_sha3_init_optim))
+		func |= CPACF_KLMD_NIP | CPACF_KLMD_DUFOP;
+	else
+		memset(&state, 0, sizeof(state));
+
+	cpacf_klmd(func, &state, in, in_len);
+
+	if (static_branch_likely(&have_sha3_init_optim))
+		kmsan_unpoison_memory(&state, out_len);
+
+	memcpy(out, &state, out_len);
+	memzero_explicit(&state, sizeof(state));
+	return true;
+}
+
+#define sha3_224_arch sha3_224_arch
+static bool sha3_224_arch(const u8 *in, size_t in_len,
+			  u8 out[SHA3_224_DIGEST_SIZE])
+{
+	return s390_sha3(CPACF_KLMD_SHA3_224, in, in_len,
+			 out, SHA3_224_DIGEST_SIZE);
+}
+
+#define sha3_256_arch sha3_256_arch
+static bool sha3_256_arch(const u8 *in, size_t in_len,
+			  u8 out[SHA3_256_DIGEST_SIZE])
+{
+	return s390_sha3(CPACF_KLMD_SHA3_256, in, in_len,
+			 out, SHA3_256_DIGEST_SIZE);
+}
+
+#define sha3_384_arch sha3_384_arch
+static bool sha3_384_arch(const u8 *in, size_t in_len,
+			  u8 out[SHA3_384_DIGEST_SIZE])
+{
+	return s390_sha3(CPACF_KLMD_SHA3_384, in, in_len,
+			 out, SHA3_384_DIGEST_SIZE);
+}
+
+#define sha3_512_arch sha3_512_arch
+static bool sha3_512_arch(const u8 *in, size_t in_len,
+			  u8 out[SHA3_512_DIGEST_SIZE])
+{
+	return s390_sha3(CPACF_KLMD_SHA3_512, in, in_len,
+			 out, SHA3_512_DIGEST_SIZE);
+}
+
+#define sha3_mod_init_arch sha3_mod_init_arch
+static void sha3_mod_init_arch(void)
+{
+	int num_present = 0;
+	int num_possible = 0;
+
+	if (!cpu_have_feature(S390_CPU_FEATURE_MSA))
+		return;
+	/*
+	 * Since all the SHA-3 functions are in Message-Security-Assist
+	 * Extension 6, just treat them as all or nothing.  This way we need
+	 * only one static_key.
+	 */
+#define QUERY(opcode, func) \
+	({ num_present += !!cpacf_query_func(opcode, func); num_possible++; })
+	QUERY(CPACF_KIMD, CPACF_KIMD_SHA3_224);
+	QUERY(CPACF_KIMD, CPACF_KIMD_SHA3_256);
+	QUERY(CPACF_KIMD, CPACF_KIMD_SHA3_384);
+	QUERY(CPACF_KIMD, CPACF_KIMD_SHA3_512);
+	QUERY(CPACF_KLMD, CPACF_KLMD_SHA3_224);
+	QUERY(CPACF_KLMD, CPACF_KLMD_SHA3_256);
+	QUERY(CPACF_KLMD, CPACF_KLMD_SHA3_384);
+	QUERY(CPACF_KLMD, CPACF_KLMD_SHA3_512);
+#undef QUERY
+
+	if (num_present == num_possible) {
+		static_branch_enable(&have_sha3);
+		if (test_facility(86))
+			static_branch_enable(&have_sha3_init_optim);
+	} else if (num_present != 0) {
+		pr_warn("Unsupported combination of SHA-3 facilities\n");
+	}
+}