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, 93 insertions, 0 deletions

diff --git a/arch/microblaze/Makefile b/arch/microblaze/Makefile
new file mode 100644
index 000000000..02e6be9c5
--- /dev/null
+++ b/arch/microblaze/Makefile
@@ -0,0 +1,93 @@
+# SPDX-License-Identifier: GPL-2.0
+KBUILD_DEFCONFIG := mmu_defconfig
+
+UTS_SYSNAME = -DUTS_SYSNAME=\"Linux\"
+
+# What CPU version are we building for, and crack it open
+# as major.minor.rev
+CPU_VER   := $(CONFIG_XILINX_MICROBLAZE0_HW_VER)
+CPU_MAJOR := $(word 1, $(subst ., , $(CPU_VER)))
+CPU_MINOR := $(word 2, $(subst ., , $(CPU_VER)))
+CPU_REV   := $(word 3, $(subst ., , $(CPU_VER)))
+
+export CPU_VER CPU_MAJOR CPU_MINOR CPU_REV
+
+# Use cpu-related CONFIG_ vars to set compile options.
+# The various CONFIG_XILINX cpu features options are integers 0/1/2...
+# rather than bools y/n
+
+# Work out HW multipler support. This is tricky.
+# 1. Spartan2 has no HW multipliers.
+# 2. MicroBlaze v3.x always uses them, except in Spartan 2
+# 3. All other FPGa/CPU ver combos, we can trust the CONFIG_ settings
+ifeq (,$(findstring spartan2,$(CONFIG_XILINX_MICROBLAZE0_FAMILY)))
+  ifeq ($(CPU_MAJOR),3)
+    CPUFLAGS-1 += -mno-xl-soft-mul
+  else
+    # USE_HW_MUL can be 0, 1, or 2, defining a hierarchy of HW Mul support.
+    CPUFLAGS-$(subst 1,,$(CONFIG_XILINX_MICROBLAZE0_USE_HW_MUL)) += -mxl-multiply-high
+    CPUFLAGS-$(CONFIG_XILINX_MICROBLAZE0_USE_HW_MUL) += -mno-xl-soft-mul
+  endif
+endif
+CPUFLAGS-$(CONFIG_XILINX_MICROBLAZE0_USE_DIV) += -mno-xl-soft-div
+CPUFLAGS-$(CONFIG_XILINX_MICROBLAZE0_USE_BARREL) += -mxl-barrel-shift
+CPUFLAGS-$(CONFIG_XILINX_MICROBLAZE0_USE_PCMP_INSTR) += -mxl-pattern-compare
+
+ifdef CONFIG_CPU_BIG_ENDIAN
+KBUILD_CFLAGS += -mbig-endian
+KBUILD_AFLAGS += -mbig-endian
+KBUILD_LDFLAGS += -EB
+else
+KBUILD_CFLAGS += -mlittle-endian
+KBUILD_AFLAGS += -mlittle-endian
+KBUILD_LDFLAGS += -EL
+endif
+
+CPUFLAGS-1 += $(call cc-option,-mcpu=v$(CPU_VER))
+
+# r31 holds current when in kernel mode
+KBUILD_CFLAGS += -ffixed-r31 $(CPUFLAGS-y) $(CPUFLAGS-1) $(CPUFLAGS-2)
+
+libs-y += arch/microblaze/lib/
+
+boot := arch/microblaze/boot
+
+# Are we making a simpleImage.<boardname> target? If so, crack out the boardname
+DTB:=$(subst simpleImage.,,$(filter simpleImage.%, $(MAKECMDGOALS)))
+
+export DTB
+
+all: linux.bin
+
+archheaders:
+	$(Q)$(MAKE) $(build)=arch/microblaze/kernel/syscalls all
+
+PHONY += linux.bin linux.bin.gz linux.bin.ub
+linux.bin.ub linux.bin.gz: linux.bin
+linux.bin: vmlinux
+linux.bin linux.bin.gz linux.bin.ub:
+	$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
+	@echo 'Kernel: $(boot)/$@ is ready' ' (#'$(or $(KBUILD_BUILD_VERSION),`cat .version`)')'
+
+PHONY += simpleImage.$(DTB)
+simpleImage.$(DTB): vmlinux
+	$(Q)$(MAKE) $(build)=$(boot) $(addprefix $(boot)/$@., ub unstrip strip)
+	@echo 'Kernel: $(boot)/$@ is ready' ' (#'$(or $(KBUILD_BUILD_VERSION),`cat .version`)')'
+
+define archhelp
+  echo '* linux.bin    - Create raw binary'
+  echo '  linux.bin.gz - Create compressed raw binary'
+  echo '  linux.bin.ub - Create U-Boot wrapped raw binary'
+  echo '  simpleImage.<dt> - Create the following images with <dt>.dtb linked in'
+  echo '                    simpleImage.<dt>        : raw image'
+  echo '                    simpleImage.<dt>.ub     : raw image with U-Boot header'
+  echo '                    simpleImage.<dt>.unstrip: ELF (identical to vmlinux)'
+  echo '                    simpleImage.<dt>.strip  : stripped ELF'
+  echo '  Targets with <dt> embed a device tree blob inside the image'
+  echo '  These targets support board with firmware that does not'
+  echo '  support passing a device tree directly. Replace <dt> with the'
+  echo '  name of a dts file from the arch/microblaze/boot/dts/ directory'
+  echo '  (minus the .dts extension).'
+endef
+
+MRPROPER_FILES += $(boot)/simpleImage.*