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>

2 files changed, 202 insertions, 0 deletions

diff --git a/tools/platform/x86/amd/Makefile b/tools/platform/x86/amd/Makefile
new file mode 100644
index 000000000..5d820df58
--- /dev/null
+++ b/tools/platform/x86/amd/Makefile
@@ -0,0 +1,60 @@
+# SPDX-License-Identifier: GPL-2.0
+ifeq ($(srctree),)
+srctree := $(patsubst %/,%,$(dir $(CURDIR)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+endif
+
+# Include common tools build infrastructure
+include $(srctree)/tools/scripts/Makefile.include
+
+CC		= $(CROSS_COMPILE)gcc
+BUILD_OUTPUT	:= $(CURDIR)
+PREFIX		?= /usr
+DESTDIR		?=
+
+ifeq ("$(origin O)", "command line")
+	BUILD_OUTPUT := $(O)
+endif
+
+# Include paths: tools/include has linux/kernel.h with ARRAY_SIZE
+INCLUDES	= -I$(srctree)/tools/include
+INCLUDES	+= -I$(srctree)/tools/include/uapi
+INCLUDES	+= -I$(srctree)/include/uapi
+INCLUDES	+= -I$(srctree)/include
+
+override CFLAGS += -O2 -Wall -Wextra -D_GNU_SOURCE $(INCLUDES)
+override CFLAGS += -D_FILE_OFFSET_BITS=64
+override CFLAGS += -D__EXPORTED_HEADERS__
+
+TARGETS		= test_amd_pmf
+
+all: $(TARGETS)
+
+test_amd_pmf: test-pmf.c
+	$(QUIET_CC)$(CC) $(CFLAGS) $< -o $(BUILD_OUTPUT)/$@ $(LDFLAGS)
+
+.PHONY: clean
+clean:
+	$(call QUIET_CLEAN, test_amd_pmf)$(RM) $(BUILD_OUTPUT)/test_amd_pmf
+
+.PHONY: install
+install: $(TARGETS)
+	$(INSTALL) -d $(DESTDIR)$(PREFIX)/bin
+	$(INSTALL) $(BUILD_OUTPUT)/test_amd_pmf $(DESTDIR)$(PREFIX)/bin/test_amd_pmf
+
+.PHONY: help
+help:
+	@echo "AMD Platform Tools Makefile"
+	@echo ""
+	@echo "Targets:"
+	@echo "  all           - Build all tools (default)"
+	@echo "  test_amd_pmf  - Build the PMF test tool"
+	@echo "  clean         - Remove built files"
+	@echo "  install       - Install tools to $(PREFIX)/bin"
+	@echo ""
+	@echo "Variables:"
+	@echo "  O=<dir>        - Build output directory"
+	@echo "  PREFIX         - Installation prefix (default: /usr)"
+	@echo "  DESTDIR        - Destination directory for install"
diff --git a/tools/platform/x86/amd/test-pmf.c b/tools/platform/x86/amd/test-pmf.c
new file mode 100644
index 000000000..82978afa6
--- /dev/null
+++ b/tools/platform/x86/amd/test-pmf.c
@@ -0,0 +1,142 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * AMD Platform Management Framework Test Tool
+ *
+ * Copyright (c) 2026, Advanced Micro Devices, Inc.
+ * All Rights Reserved.
+ *
+ * Authors: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
+ *          Sanket Goswami <Sanket.Goswami@amd.com>
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+
+#include <linux/amd-pmf.h>
+#include <linux/kernel.h>
+
+#define DEVICE_NODE	"/dev/amdpmf_interface"
+
+/* Feature flag names */
+static const char * const feature_names[] = {
+	"Auto Mode",
+	"Static Power Slider",
+	"Policy Builder (Smart PC)",
+	"Dynamic Power Slider AC",
+	"Dynamic Power Slider DC",
+};
+
+static const char *banner =
+	"====================================================\n"
+	"      AMD PMF Metrics info and Feature Status\n"
+	"====================================================\n\n";
+
+/* Print feature flags */
+static void pmf_print_features(uint32_t flags)
+{
+	size_t i;
+
+	for (i = 0; i < ARRAY_SIZE(feature_names); i++)
+		printf("  [%c] %s\n", (flags & (1U << i)) ? 'x' : ' ', feature_names[i]);
+}
+
+/* Print BIOS parameters */
+static void pmf_print_bios_params(const char *type, const __u32 *params)
+{
+	int i;
+
+	for (i = 0; i < AMD_PMF_BIOS_PARAMS_MAX; i++)
+		printf("  Custom BIOS %s%d: %u\n", type, i + 1, params[i]);
+}
+
+/* Open the PMF device */
+static int pmf_open_device(void)
+{
+	int fd;
+
+	fd = open(DEVICE_NODE, O_RDONLY);
+	if (fd < 0)
+		fprintf(stderr, "Error: Cannot open %s: %s\n", DEVICE_NODE, strerror(errno));
+
+	return fd;
+}
+
+/* Query PMF info using the single IOCTL */
+static int pmf_get_info(int fd, struct amd_pmf_info *info)
+{
+	int ret;
+
+	/* Zero-initialize and set size for versioning */
+	memset(info, 0, sizeof(*info));
+	info->size = sizeof(*info);
+
+	ret = ioctl(fd, IOCTL_AMD_PMF_POPULATE_DATA, info);
+	if (ret < 0) {
+		fprintf(stderr, "Error: IOCTL_AMD_PMF_POPULATE_DATA failed: %s\n", strerror(errno));
+		return ret;
+	}
+
+	return 0;
+}
+
+static void pmf_print_info(const struct amd_pmf_info *info)
+{
+	printf("%s", banner);
+
+	/* Feature status */
+	printf("Feature Status:\n");
+	pmf_print_features(info->features_supported);
+
+	/* Device states */
+	printf("\nDevice States:\n");
+	printf("  Platform Type:     %s\n", amd_pmf_get_platform_type(info->platform_type));
+	printf("  Laptop Placement:  %s\n", amd_pmf_get_laptop_placement(info->laptop_placement));
+	printf("  Lid State:         %s\n", info->lid_state ? "Closed" : "Open");
+	printf("  User Presence:     %s\n", info->user_presence ? "Present" : "Away");
+	printf("  Slider Position:   %s\n", amd_pmf_get_slider_position(info->slider_position));
+
+	/* Thermal and power metrics */
+	printf("\nThermal/Power Metrics:\n");
+	printf("  Skin Temperature:  %d\n", info->skin_temp / 100);
+	printf("  GFX Busy:          %u\n", info->gfx_busy);
+	printf("  Ambient Light:     %d\n", info->ambient_light);
+	printf("  Avg C0 Residency:  %u\n", info->avg_c0_residency);
+	printf("  Max C0 Residency:  %u\n", info->max_c0_residency);
+	printf("  Socket Power:      %u\n", info->socket_power);
+
+	/* BIOS parameters */
+	printf("\nCustom BIOS Input Parameters:\n");
+	pmf_print_bios_params("Input", info->bios_input);
+	printf("\nCustom BIOS Output Parameters:\n");
+	pmf_print_bios_params("Output", info->bios_output);
+
+	printf("\n=================================================\n");
+}
+
+int main(void)
+{
+	struct amd_pmf_info info;
+	int fd, ret;
+
+	fd = pmf_open_device();
+	if (fd < 0)
+		return -1;
+
+	/* Query all info with single IOCTL */
+	ret = pmf_get_info(fd, &info);
+	close(fd);
+
+	if (ret < 0)
+		return -1;
+
+	pmf_print_info(&info);
+
+	return 0;
+}