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, 178 insertions, 0 deletions

diff --git a/arch/hexagon/lib/checksum.c b/arch/hexagon/lib/checksum.c
new file mode 100644
index 000000000..ba50822a0
--- /dev/null
+++ b/arch/hexagon/lib/checksum.c
@@ -0,0 +1,178 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Checksum functions for Hexagon
+ *
+ * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
+ */
+
+/*  This was derived from arch/alpha/lib/checksum.c  */
+
+
+#include <linux/module.h>
+#include <linux/string.h>
+
+#include <asm/byteorder.h>
+#include <net/checksum.h>
+#include <linux/uaccess.h>
+#include <asm/intrinsics.h>
+
+
+/*  Vector value operations  */
+#define SIGN(x, y)	((0x8000ULL*x)<<y)
+#define CARRY(x, y)	((0x0002ULL*x)<<y)
+#define SELECT(x, y)	((0x0001ULL*x)<<y)
+
+#define VR_NEGATE(a, b, c, d)	(SIGN(a, 48) + SIGN(b, 32) + SIGN(c, 16) \
+	+ SIGN(d, 0))
+#define VR_CARRY(a, b, c, d)	(CARRY(a, 48) + CARRY(b, 32) + CARRY(c, 16) \
+	+ CARRY(d, 0))
+#define VR_SELECT(a, b, c, d)	(SELECT(a, 48) + SELECT(b, 32) + SELECT(c, 16) \
+	+ SELECT(d, 0))
+
+
+/* optimized HEXAGON V3 intrinsic version */
+static inline unsigned short from64to16(u64 x)
+{
+	u64 sum;
+
+	sum = HEXAGON_P_vrmpyh_PP(x^VR_NEGATE(1, 1, 1, 1),
+			     VR_SELECT(1, 1, 1, 1));
+	sum += VR_CARRY(0, 0, 1, 0);
+	sum = HEXAGON_P_vrmpyh_PP(sum, VR_SELECT(0, 0, 1, 1));
+
+	return 0xFFFF & sum;
+}
+
+/*
+ * computes the checksum of the TCP/UDP pseudo-header
+ * returns a 16-bit checksum, already complemented.
+ */
+__sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
+			  __u32 len, __u8 proto, __wsum sum)
+{
+	return (__force __sum16)~from64to16(
+		(__force u64)saddr + (__force u64)daddr +
+		(__force u64)sum + ((len + proto) << 8));
+}
+
+__wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
+			  __u32 len, __u8 proto, __wsum sum)
+{
+	u64 result;
+
+	result = (__force u64)saddr + (__force u64)daddr +
+		 (__force u64)sum + ((len + proto) << 8);
+
+	/* Fold down to 32-bits so we don't lose in the typedef-less
+	   network stack.  */
+	/* 64 to 33 */
+	result = (result & 0xffffffffUL) + (result >> 32);
+	/* 33 to 32 */
+	result = (result & 0xffffffffUL) + (result >> 32);
+	return (__force __wsum)result;
+}
+EXPORT_SYMBOL(csum_tcpudp_nofold);
+
+/*
+ * Do a 64-bit checksum on an arbitrary memory area..
+ *
+ * This isn't a great routine, but it's not _horrible_ either. The
+ * inner loop could be unrolled a bit further, and there are better
+ * ways to do the carry, but this is reasonable.
+ */
+
+/* optimized HEXAGON intrinsic version, with over read fixed */
+unsigned int do_csum(const void *voidptr, int len)
+{
+	u64 sum0, sum1, x0, x1, *ptr8_o, *ptr8_e, *ptr8;
+	int i, start, mid, end, mask;
+	const char *ptr = voidptr;
+	unsigned short *ptr2;
+	unsigned int *ptr4;
+
+	if (len <= 0)
+		return 0;
+
+	start = 0xF & (16-(((int) ptr) & 0xF)) ;
+	mask  = 0x7fffffffUL >> HEXAGON_R_cl0_R(len);
+	start = start & mask ;
+
+	mid = len - start;
+	end = mid & 0xF;
+	mid = mid>>4;
+	sum0 = mid << 18;
+	sum1 = 0;
+
+	if (start & 1)
+		sum0 += (u64) (ptr[0] << 8);
+	ptr2 = (unsigned short *) &ptr[start & 1];
+	if (start & 2)
+		sum1 += (u64) ptr2[0];
+	ptr4 = (unsigned int *) &ptr[start & 3];
+	if (start & 4) {
+		sum0 = HEXAGON_P_vrmpyhacc_PP(sum0,
+			VR_NEGATE(0, 0, 1, 1)^((u64)ptr4[0]),
+			VR_SELECT(0, 0, 1, 1));
+		sum0 += VR_SELECT(0, 0, 1, 0);
+	}
+	ptr8 = (u64 *) &ptr[start & 7];
+	if (start & 8) {
+		sum1 = HEXAGON_P_vrmpyhacc_PP(sum1,
+			VR_NEGATE(1, 1, 1, 1)^(ptr8[0]),
+			VR_SELECT(1, 1, 1, 1));
+		sum1 += VR_CARRY(0, 0, 1, 0);
+	}
+	ptr8_o = (u64 *) (ptr + start);
+	ptr8_e = (u64 *) (ptr + start + 8);
+
+	if (mid) {
+		x0 = *ptr8_e; ptr8_e += 2;
+		x1 = *ptr8_o; ptr8_o += 2;
+		if (mid > 1)
+			for (i = 0; i < mid-1; i++) {
+				sum0 = HEXAGON_P_vrmpyhacc_PP(sum0,
+					x0^VR_NEGATE(1, 1, 1, 1),
+					VR_SELECT(1, 1, 1, 1));
+				sum1 = HEXAGON_P_vrmpyhacc_PP(sum1,
+					x1^VR_NEGATE(1, 1, 1, 1),
+					VR_SELECT(1, 1, 1, 1));
+				x0 = *ptr8_e; ptr8_e += 2;
+				x1 = *ptr8_o; ptr8_o += 2;
+			}
+		sum0 = HEXAGON_P_vrmpyhacc_PP(sum0, x0^VR_NEGATE(1, 1, 1, 1),
+			VR_SELECT(1, 1, 1, 1));
+		sum1 = HEXAGON_P_vrmpyhacc_PP(sum1, x1^VR_NEGATE(1, 1, 1, 1),
+			VR_SELECT(1, 1, 1, 1));
+	}
+
+	ptr4 = (unsigned int *) &ptr[start + (mid * 16) + (end & 8)];
+	if (end & 4) {
+		sum1 = HEXAGON_P_vrmpyhacc_PP(sum1,
+			VR_NEGATE(0, 0, 1, 1)^((u64)ptr4[0]),
+			VR_SELECT(0, 0, 1, 1));
+		sum1 += VR_SELECT(0, 0, 1, 0);
+	}
+	ptr2 = (unsigned short *) &ptr[start + (mid * 16) + (end & 12)];
+	if (end & 2)
+		sum0 += (u64) ptr2[0];
+
+	if (end & 1)
+		sum1 += (u64) ptr[start + (mid * 16) + (end & 14)];
+
+	ptr8 = (u64 *) &ptr[start + (mid * 16)];
+	if (end & 8) {
+		sum0 = HEXAGON_P_vrmpyhacc_PP(sum0,
+			VR_NEGATE(1, 1, 1, 1)^(ptr8[0]),
+			VR_SELECT(1, 1, 1, 1));
+		sum0 += VR_CARRY(0, 0, 1, 0);
+	}
+	sum0 = HEXAGON_P_vrmpyh_PP((sum0+sum1)^VR_NEGATE(0, 0, 0, 1),
+		VR_SELECT(0, 0, 1, 1));
+	sum0 += VR_NEGATE(0, 0, 0, 1);
+	sum0 = HEXAGON_P_vrmpyh_PP(sum0, VR_SELECT(0, 0, 1, 1));
+
+	if (start & 1)
+		sum0 = (sum0 << 8) | (0xFF & (sum0 >> 8));
+
+	return 0xFFFF & sum0;
+}