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, 270 insertions, 0 deletions

diff --git a/sound/ppc/beep.c b/sound/ppc/beep.c
new file mode 100644
index 000000000..1b03a7961
--- /dev/null
+++ b/sound/ppc/beep.c
@@ -0,0 +1,270 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Beep using pcm
+ *
+ * Copyright (c) by Takashi Iwai <tiwai@suse.de>
+ */
+
+#include <linux/io.h>
+#include <asm/irq.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/input.h>
+#include <linux/pci.h>
+#include <linux/dma-mapping.h>
+#include <sound/core.h>
+#include <sound/control.h>
+#include "pmac.h"
+
+struct pmac_beep {
+	int running;		/* boolean */
+	int volume;		/* mixer volume: 0-100 */
+	int volume_play;	/* currently playing volume */
+	int hz;
+	int nsamples;
+	short *buf;		/* allocated wave buffer */
+	dma_addr_t addr;	/* physical address of buffer */
+	struct input_dev *dev;
+};
+
+/*
+ * stop beep if running
+ */
+void snd_pmac_beep_stop(struct snd_pmac *chip)
+{
+	struct pmac_beep *beep = chip->beep;
+	if (beep && beep->running) {
+		beep->running = 0;
+		snd_pmac_beep_dma_stop(chip);
+	}
+}
+
+/*
+ * Stuff for outputting a beep.  The values range from -327 to +327
+ * so we can multiply by an amplitude in the range 0..100 to get a
+ * signed short value to put in the output buffer.
+ */
+static const short beep_wform[256] = {
+	0,	40,	79,	117,	153,	187,	218,	245,
+	269,	288,	304,	316,	323,	327,	327,	324,
+	318,	310,	299,	288,	275,	262,	249,	236,
+	224,	213,	204,	196,	190,	186,	183,	182,
+	182,	183,	186,	189,	192,	196,	200,	203,
+	206,	208,	209,	209,	209,	207,	204,	201,
+	197,	193,	188,	183,	179,	174,	170,	166,
+	163,	161,	160,	159,	159,	160,	161,	162,
+	164,	166,	168,	169,	171,	171,	171,	170,
+	169,	167,	163,	159,	155,	150,	144,	139,
+	133,	128,	122,	117,	113,	110,	107,	105,
+	103,	103,	103,	103,	104,	104,	105,	105,
+	105,	103,	101,	97,	92,	86,	78,	68,
+	58,	45,	32,	18,	3,	-11,	-26,	-41,
+	-55,	-68,	-79,	-88,	-95,	-100,	-102,	-102,
+	-99,	-93,	-85,	-75,	-62,	-48,	-33,	-16,
+	0,	16,	33,	48,	62,	75,	85,	93,
+	99,	102,	102,	100,	95,	88,	79,	68,
+	55,	41,	26,	11,	-3,	-18,	-32,	-45,
+	-58,	-68,	-78,	-86,	-92,	-97,	-101,	-103,
+	-105,	-105,	-105,	-104,	-104,	-103,	-103,	-103,
+	-103,	-105,	-107,	-110,	-113,	-117,	-122,	-128,
+	-133,	-139,	-144,	-150,	-155,	-159,	-163,	-167,
+	-169,	-170,	-171,	-171,	-171,	-169,	-168,	-166,
+	-164,	-162,	-161,	-160,	-159,	-159,	-160,	-161,
+	-163,	-166,	-170,	-174,	-179,	-183,	-188,	-193,
+	-197,	-201,	-204,	-207,	-209,	-209,	-209,	-208,
+	-206,	-203,	-200,	-196,	-192,	-189,	-186,	-183,
+	-182,	-182,	-183,	-186,	-190,	-196,	-204,	-213,
+	-224,	-236,	-249,	-262,	-275,	-288,	-299,	-310,
+	-318,	-324,	-327,	-327,	-323,	-316,	-304,	-288,
+	-269,	-245,	-218,	-187,	-153,	-117,	-79,	-40,
+};
+
+#define BEEP_SRATE	22050	/* 22050 Hz sample rate */
+#define BEEP_BUFLEN	512
+#define BEEP_VOLUME	15	/* 0 - 100 */
+
+static int snd_pmac_beep_event(struct input_dev *dev, unsigned int type,
+			       unsigned int code, int hz)
+{
+	struct snd_pmac *chip;
+	struct pmac_beep *beep;
+	int beep_speed = 0;
+	int srate;
+	int period, ncycles, nsamples;
+	int i, j, f;
+	short *p;
+
+	if (type != EV_SND)
+		return -1;
+
+	switch (code) {
+	case SND_BELL: if (hz) hz = 1000; break;
+	case SND_TONE: break;
+	default: return -1;
+	}
+
+	chip = input_get_drvdata(dev);
+	if (!chip)
+		return -1;
+	beep = chip->beep;
+	if (!beep)
+		return -1;
+
+	if (! hz) {
+		guard(spinlock_irqsave)(&chip->reg_lock);
+		if (beep->running)
+			snd_pmac_beep_stop(chip);
+		return 0;
+	}
+
+	beep_speed = snd_pmac_rate_index(chip, &chip->playback, BEEP_SRATE);
+	srate = chip->freq_table[beep_speed];
+
+	if (hz <= srate / BEEP_BUFLEN || hz > srate / 2)
+		hz = 1000;
+
+	scoped_guard(spinlock_irqsave, &chip->reg_lock) {
+		if (chip->playback.running || chip->capture.running || beep->running)
+			return 0;
+		beep->running = 1;
+	}
+
+	if (hz == beep->hz && beep->volume == beep->volume_play) {
+		nsamples = beep->nsamples;
+	} else {
+		period = srate * 256 / hz;	/* fixed point */
+		ncycles = BEEP_BUFLEN * 256 / period;
+		nsamples = (period * ncycles) >> 8;
+		f = ncycles * 65536 / nsamples;
+		j = 0;
+		p = beep->buf;
+		for (i = 0; i < nsamples; ++i, p += 2) {
+			p[0] = p[1] = beep_wform[j >> 8] * beep->volume;
+			j = (j + f) & 0xffff;
+		}
+		beep->hz = hz;
+		beep->volume_play = beep->volume;
+		beep->nsamples = nsamples;
+	}
+
+	guard(spinlock_irqsave)(&chip->reg_lock);
+	snd_pmac_beep_dma_start(chip, beep->nsamples * 4, beep->addr, beep_speed);
+	return 0;
+}
+
+/*
+ * beep volume mixer
+ */
+
+static int snd_pmac_info_beep(struct snd_kcontrol *kcontrol,
+			      struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = 1;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = 100;
+	return 0;
+}
+
+static int snd_pmac_get_beep(struct snd_kcontrol *kcontrol,
+			     struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_pmac *chip = snd_kcontrol_chip(kcontrol);
+	if (snd_BUG_ON(!chip->beep))
+		return -ENXIO;
+	ucontrol->value.integer.value[0] = chip->beep->volume;
+	return 0;
+}
+
+static int snd_pmac_put_beep(struct snd_kcontrol *kcontrol,
+			     struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_pmac *chip = snd_kcontrol_chip(kcontrol);
+	unsigned int oval, nval;
+	if (snd_BUG_ON(!chip->beep))
+		return -ENXIO;
+	oval = chip->beep->volume;
+	nval = ucontrol->value.integer.value[0];
+	if (nval > 100)
+		return -EINVAL;
+	chip->beep->volume = nval;
+	return oval != chip->beep->volume;
+}
+
+static const struct snd_kcontrol_new snd_pmac_beep_mixer = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "Beep Playback Volume",
+	.info = snd_pmac_info_beep,
+	.get = snd_pmac_get_beep,
+	.put = snd_pmac_put_beep,
+};
+
+/* Initialize beep stuff */
+int snd_pmac_attach_beep(struct snd_pmac *chip)
+{
+	struct pmac_beep *beep;
+	struct input_dev *input_dev;
+	struct snd_kcontrol *beep_ctl;
+	void *dmabuf;
+	int err = -ENOMEM;
+
+	beep = kzalloc_obj(*beep);
+	if (! beep)
+		return -ENOMEM;
+	dmabuf = dma_alloc_coherent(&chip->pdev->dev, BEEP_BUFLEN * 4,
+				    &beep->addr, GFP_KERNEL);
+	input_dev = input_allocate_device();
+	if (! dmabuf || ! input_dev)
+		goto fail1;
+
+	/* FIXME: set more better values */
+	input_dev->name = "PowerMac Beep";
+	input_dev->phys = "powermac/beep";
+	input_dev->id.bustype = BUS_ADB;
+	input_dev->id.vendor = 0x001f;
+	input_dev->id.product = 0x0001;
+	input_dev->id.version = 0x0100;
+
+	input_dev->evbit[0] = BIT_MASK(EV_SND);
+	input_dev->sndbit[0] = BIT_MASK(SND_BELL) | BIT_MASK(SND_TONE);
+	input_dev->event = snd_pmac_beep_event;
+	input_dev->dev.parent = &chip->pdev->dev;
+	input_set_drvdata(input_dev, chip);
+
+	beep->dev = input_dev;
+	beep->buf = dmabuf;
+	beep->volume = BEEP_VOLUME;
+	beep->running = 0;
+
+	beep_ctl = snd_ctl_new1(&snd_pmac_beep_mixer, chip);
+	err = snd_ctl_add(chip->card, beep_ctl);
+	if (err < 0)
+		goto fail1;
+
+	chip->beep = beep;
+
+	err = input_register_device(beep->dev);
+	if (err)
+		goto fail2;
+ 
+ 	return 0;
+ 
+ fail2:	snd_ctl_remove(chip->card, beep_ctl);
+ fail1:	input_free_device(input_dev);
+	if (dmabuf)
+		dma_free_coherent(&chip->pdev->dev, BEEP_BUFLEN * 4,
+				  dmabuf, beep->addr);
+	kfree(beep);
+	return err;
+}
+
+void snd_pmac_detach_beep(struct snd_pmac *chip)
+{
+	if (chip->beep) {
+		input_unregister_device(chip->beep->dev);
+		dma_free_coherent(&chip->pdev->dev, BEEP_BUFLEN * 4,
+				  chip->beep->buf, chip->beep->addr);
+		kfree(chip->beep);
+		chip->beep = NULL;
+	}
+}