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, 411 insertions, 0 deletions

diff --git a/arch/arm64/tools/gen-sysreg.awk b/arch/arm64/tools/gen-sysreg.awk
new file mode 100755
index 000000000..53844f5c5
--- /dev/null
+++ b/arch/arm64/tools/gen-sysreg.awk
@@ -0,0 +1,411 @@
+#!/bin/awk -f
+# SPDX-License-Identifier: GPL-2.0
+# gen-sysreg.awk: arm64 sysreg header generator
+#
+# Usage: awk -f gen-sysreg.awk sysregs.txt
+
+function block_current() {
+	return __current_block[__current_block_depth];
+}
+
+# Log an error and terminate
+function fatal(msg) {
+	print "Error at " NR ": " msg > "/dev/stderr"
+
+	printf "Current block nesting:"
+
+	for (i = 0; i <= __current_block_depth; i++) {
+		printf " " __current_block[i]
+	}
+	printf "\n"
+
+	exit 1
+}
+
+# Enter a new block, setting the active block to @block
+function block_push(block) {
+	__current_block[++__current_block_depth] = block
+}
+
+# Exit a block, setting the active block to the parent block
+function block_pop() {
+	if (__current_block_depth == 0)
+		fatal("error: block_pop() in root block")
+
+	__current_block_depth--;
+}
+
+# Sanity check the number of records for a field makes sense. If not, produce
+# an error and terminate.
+function expect_fields(nf) {
+	if (NF != nf)
+		fatal(NF " fields found where " nf " expected")
+}
+
+# Print a CPP macro definition, padded with spaces so that the macro bodies
+# line up in a column
+function define(prefix, name, val) {
+	printf "%-56s%s\n", "#define " prefix name, val
+}
+
+# Same as above, but without a prefix
+function define_reg(name, val) {
+	define(null, name, val)
+}
+
+# Print standard BITMASK/SHIFT/WIDTH CPP definitions for a field
+function define_field(prefix, reg, field, msb, lsb) {
+	define(prefix, reg "_" field, "GENMASK(" msb ", " lsb ")")
+	define(prefix, reg "_" field "_MASK", "GENMASK(" msb ", " lsb ")")
+	define(prefix, reg "_" field "_SHIFT", lsb)
+	define(prefix, reg "_" field "_WIDTH", msb - lsb + 1)
+}
+
+# Print a field _SIGNED definition for a field
+function define_field_sign(prefix, reg, field, sign) {
+	define(prefix, reg "_" field "_SIGNED", sign)
+}
+
+# Print the Res0, Res1, Unkn masks
+function define_resx_unkn(prefix, reg, res0, res1, unkn) {
+	if (res0 != null)
+		define(prefix, reg "_RES0", "(" res0 ")")
+	if (res1 != null)
+		define(prefix, reg "_RES1", "(" res1 ")")
+	if (unkn != null)
+		define(prefix, reg "_UNKN", "(" unkn ")")
+	if (res0 != null || res1 != null || unkn != null)
+		print ""
+}
+
+# Parse a "<msb>[:<lsb>]" string into the global variables @msb and @lsb
+function parse_bitdef(reg, field, bitdef, _bits)
+{
+	if (bitdef ~ /^[0-9]+$/) {
+		msb = bitdef
+		lsb = bitdef
+	} else if (split(bitdef, _bits, ":") == 2) {
+		msb = _bits[1]
+		lsb = _bits[2]
+	} else {
+		fatal("invalid bit-range definition '" bitdef "'")
+	}
+
+
+	if (msb != next_bit)
+		fatal(reg "." field " starts at " msb " not " next_bit)
+	if (63 < msb || msb < 0)
+		fatal(reg "." field " invalid high bit in '" bitdef "'")
+	if (63 < lsb || lsb < 0)
+		fatal(reg "." field " invalid low bit in '" bitdef "'")
+	if (msb < lsb)
+		fatal(reg "." field " invalid bit-range '" bitdef "'")
+	if (low > high)
+		fatal(reg "." field " has invalid range " high "-" low)
+
+	next_bit = lsb - 1
+}
+
+BEGIN {
+	print "#ifndef __ASM_SYSREG_DEFS_H"
+	print "#define __ASM_SYSREG_DEFS_H"
+	print ""
+	print "/* Generated file - do not edit */"
+	print ""
+
+	__current_block_depth = 0
+	__current_block[__current_block_depth] = "Root"
+}
+
+END {
+	if (__current_block_depth != 0)
+		fatal("Missing terminator for " block_current() " block")
+
+	print "#endif /* __ASM_SYSREG_DEFS_H */"
+}
+
+# skip blank lines and comment lines
+/^$/ { next }
+/^[\t ]*#/ { next }
+
+$1 == "SysregFields" && block_current() == "Root" {
+	block_push("SysregFields")
+
+	expect_fields(2)
+
+	reg = $2
+
+	res0 = "UL(0)"
+	res1 = "UL(0)"
+	unkn = "UL(0)"
+
+	if (reg in defined_fields)
+		fatal("Duplicate SysregFields definition for " reg)
+	defined_fields[reg] = 1
+
+	next_bit = 63
+
+	delete seen_prefixes
+
+	next
+}
+
+$1 == "EndSysregFields" && block_current() == "SysregFields" {
+	expect_fields(1)
+	if (next_bit >= 0)
+		fatal("Unspecified bits in " reg)
+
+	define_resx_unkn(prefix, reg, res0, res1, unkn)
+
+	reg = null
+	res0 = null
+	res1 = null
+	unkn = null
+
+	block_pop()
+	next
+}
+
+$1 == "Sysreg" && block_current() == "Root" {
+	block_push("Sysreg")
+
+	expect_fields(7)
+
+	reg = $2
+	op0 = $3
+	op1 = $4
+	crn = $5
+	crm = $6
+	op2 = $7
+
+	res0 = "UL(0)"
+	res1 = "UL(0)"
+	unkn = "UL(0)"
+
+	if (reg in defined_regs)
+		fatal("Duplicate Sysreg definition for " reg)
+	defined_regs[reg] = 1
+
+	define_reg("REG_" reg, "S" op0 "_" op1 "_C" crn "_C" crm "_" op2)
+	define_reg("SYS_" reg, "sys_reg(" op0 ", " op1 ", " crn ", " crm ", " op2 ")")
+
+	define_reg("SYS_" reg "_Op0", op0)
+	define_reg("SYS_" reg "_Op1", op1)
+	define_reg("SYS_" reg "_CRn", crn)
+	define_reg("SYS_" reg "_CRm", crm)
+	define_reg("SYS_" reg "_Op2", op2)
+
+	print ""
+
+	prefix = null
+	next_bit = 63
+
+	delete seen_prefixes
+
+	next
+}
+
+$1 == "EndSysreg" && block_current() == "Sysreg" {
+	expect_fields(1)
+	if (next_bit >= 0)
+		fatal("Unspecified bits in " reg)
+
+	define_resx_unkn(prefix, reg, res0, res1, unkn)
+
+	reg = null
+	op0 = null
+	op1 = null
+	crn = null
+	crm = null
+	op2 = null
+	res0 = null
+	res1 = null
+	unkn = null
+	prefix = null
+
+	block_pop()
+	next
+}
+
+# Currently this is effectivey a comment, in future we may want to emit
+# defines for the fields. We do emit RESx and UNKN values in any case.
+($1 == "Fields" || $1 == "Mapping") && block_current() == "Sysreg" {
+	expect_fields(2)
+
+	if (next_bit != 63)
+		fatal("Some fields already defined for " reg)
+
+	print "/* For " reg " fields see " $2 " */"
+	print ""
+
+	next_bit = -1
+	res0 = $2 "_RES0"
+	res1 = $2 "_RES1"
+	unkn = $2 "_UNKN"
+
+	next
+}
+
+$1 == "Res0" && (block_current() == "Sysreg" || block_current() == "SysregFields" || block_current() == "Prefix") {
+	expect_fields(2)
+	parse_bitdef(reg, "RES0", $2)
+	field = "RES0_" msb "_" lsb
+
+	res0 = res0 " | GENMASK_ULL(" msb ", " lsb ")"
+
+	next
+}
+
+$1 == "Res1" && (block_current() == "Sysreg" || block_current() == "SysregFields" || block_current() == "Prefix") {
+	expect_fields(2)
+	parse_bitdef(reg, "RES1", $2)
+	field = "RES1_" msb "_" lsb
+
+	res1 = res1 " | GENMASK_ULL(" msb ", " lsb ")"
+
+	next
+}
+
+$1 == "Unkn" && (block_current() == "Sysreg" || block_current() == "SysregFields" || block_current() == "Prefix") {
+	expect_fields(2)
+	parse_bitdef(reg, "UNKN", $2)
+	field = "UNKN_" msb "_" lsb
+
+	unkn = unkn " | GENMASK_ULL(" msb ", " lsb ")"
+
+	next
+}
+
+$1 == "Field" && (block_current() == "Sysreg" || block_current() == "SysregFields" || block_current() == "Prefix") {
+	expect_fields(3)
+	field = $3
+	parse_bitdef(reg, field, $2)
+
+	define_field(prefix, reg, field, msb, lsb)
+	print ""
+
+	next
+}
+
+$1 == "Raz" && (block_current() == "Sysreg" || block_current() == "SysregFields" || block_current() == "Prefix") {
+	expect_fields(2)
+	parse_bitdef(reg, field, $2)
+
+	next
+}
+
+$1 == "SignedEnum" && (block_current() == "Sysreg" || block_current() == "SysregFields" || block_current() == "Prefix") {
+	block_push("Enum")
+
+	expect_fields(3)
+	field = $3
+	parse_bitdef(reg, field, $2)
+
+	define_field(prefix, reg, field, msb, lsb)
+	define_field_sign(prefix, reg, field, "true")
+
+	delete seen_enum_vals
+
+	next
+}
+
+$1 == "UnsignedEnum" && (block_current() == "Sysreg" || block_current() == "SysregFields" || block_current() == "Prefix") {
+	block_push("Enum")
+
+	expect_fields(3)
+	field = $3
+	parse_bitdef(reg, field, $2)
+
+	define_field(prefix, reg, field, msb, lsb)
+	define_field_sign(prefix, reg, field, "false")
+
+	delete seen_enum_vals
+
+	next
+}
+
+$1 == "Enum" && (block_current() == "Sysreg" || block_current() == "SysregFields" || block_current() == "Prefix") {
+	block_push("Enum")
+
+	expect_fields(3)
+	field = $3
+	parse_bitdef(reg, field, $2)
+
+	define_field(prefix, reg, field, msb, lsb)
+
+	delete seen_enum_vals
+
+	next
+}
+
+$1 == "EndEnum" && block_current() == "Enum" {
+	expect_fields(1)
+
+	field = null
+	msb = null
+	lsb = null
+	print ""
+
+	delete seen_enum_vals
+
+	block_pop()
+	next
+}
+
+/0b[01]+/ && block_current() == "Enum" {
+	expect_fields(2)
+	val = $1
+	name = $2
+
+	if (val in seen_enum_vals)
+		fatal("Duplicate Enum value " val " for " name)
+	seen_enum_vals[val] = 1
+
+	define(prefix, reg "_" field "_" name, "UL(" val ")")
+	next
+}
+
+$1 == "Prefix" && (block_current() == "Sysreg" || block_current() == "SysregFields") {
+	block_push("Prefix")
+
+	expect_fields(2)
+
+	if (next_bit < 63)
+		fatal("Prefixed fields must precede non-prefixed fields (" reg ")")
+
+	prefix = $2 "_"
+
+	if (prefix in seen_prefixes)
+		fatal("Duplicate prefix " prefix " for " reg)
+	seen_prefixes[prefix] = 1
+
+	res0 = "UL(0)"
+	res1 = "UL(0)"
+	unkn = "UL(0)"
+	next_bit = 63
+
+	next
+}
+
+$1 == "EndPrefix" && block_current() == "Prefix" {
+	expect_fields(1)
+	if (next_bit >= 0)
+		fatal("Unspecified bits in prefix " prefix " for " reg)
+
+	define_resx_unkn(prefix, reg, res0, res1, unkn)
+
+	prefix = null
+	res0 = "UL(0)"
+	res1 = "UL(0)"
+	unkn = "UL(0)"
+	next_bit = 63
+
+	block_pop()
+
+	next
+}
+
+# Any lines not handled by previous rules are unexpected
+{
+	fatal("unhandled statement")
+}