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, 410 insertions, 0 deletions

diff --git a/drivers/clk/ti/apll.c b/drivers/clk/ti/apll.c
new file mode 100644
index 000000000..31bf097f8
--- /dev/null
+++ b/drivers/clk/ti/apll.c
@@ -0,0 +1,410 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * OMAP APLL clock support
+ *
+ * Copyright (C) 2013 Texas Instruments, Inc.
+ *
+ * J Keerthy <j-keerthy@ti.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/err.h>
+#include <linux/string.h>
+#include <linux/log2.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/clk/ti.h>
+#include <linux/delay.h>
+
+#include "clock.h"
+
+#define APLL_FORCE_LOCK 0x1
+#define APLL_AUTO_IDLE	0x2
+#define MAX_APLL_WAIT_TRIES		1000000
+
+#undef pr_fmt
+#define pr_fmt(fmt) "%s: " fmt, __func__
+
+static int dra7_apll_enable(struct clk_hw *hw)
+{
+	struct clk_hw_omap *clk = to_clk_hw_omap(hw);
+	int r = 0, i = 0;
+	struct dpll_data *ad;
+	const char *clk_name;
+	u8 state = 1;
+	u32 v;
+
+	ad = clk->dpll_data;
+	if (!ad)
+		return -EINVAL;
+
+	clk_name = clk_hw_get_name(&clk->hw);
+
+	state <<= __ffs(ad->idlest_mask);
+
+	/* Check is already locked */
+	v = ti_clk_ll_ops->clk_readl(&ad->idlest_reg);
+
+	if ((v & ad->idlest_mask) == state)
+		return r;
+
+	v = ti_clk_ll_ops->clk_readl(&ad->control_reg);
+	v &= ~ad->enable_mask;
+	v |= APLL_FORCE_LOCK << __ffs(ad->enable_mask);
+	ti_clk_ll_ops->clk_writel(v, &ad->control_reg);
+
+	state <<= __ffs(ad->idlest_mask);
+
+	while (1) {
+		v = ti_clk_ll_ops->clk_readl(&ad->idlest_reg);
+		if ((v & ad->idlest_mask) == state)
+			break;
+		if (i > MAX_APLL_WAIT_TRIES)
+			break;
+		i++;
+		udelay(1);
+	}
+
+	if (i == MAX_APLL_WAIT_TRIES) {
+		pr_warn("clock: %s failed transition to '%s'\n",
+			clk_name, (state) ? "locked" : "bypassed");
+		r = -EBUSY;
+	} else
+		pr_debug("clock: %s transition to '%s' in %d loops\n",
+			 clk_name, (state) ? "locked" : "bypassed", i);
+
+	return r;
+}
+
+static void dra7_apll_disable(struct clk_hw *hw)
+{
+	struct clk_hw_omap *clk = to_clk_hw_omap(hw);
+	struct dpll_data *ad;
+	u8 state = 1;
+	u32 v;
+
+	ad = clk->dpll_data;
+
+	state <<= __ffs(ad->idlest_mask);
+
+	v = ti_clk_ll_ops->clk_readl(&ad->control_reg);
+	v &= ~ad->enable_mask;
+	v |= APLL_AUTO_IDLE << __ffs(ad->enable_mask);
+	ti_clk_ll_ops->clk_writel(v, &ad->control_reg);
+}
+
+static int dra7_apll_is_enabled(struct clk_hw *hw)
+{
+	struct clk_hw_omap *clk = to_clk_hw_omap(hw);
+	struct dpll_data *ad;
+	u32 v;
+
+	ad = clk->dpll_data;
+
+	v = ti_clk_ll_ops->clk_readl(&ad->control_reg);
+	v &= ad->enable_mask;
+
+	v >>= __ffs(ad->enable_mask);
+
+	return v == APLL_AUTO_IDLE ? 0 : 1;
+}
+
+static u8 dra7_init_apll_parent(struct clk_hw *hw)
+{
+	return 0;
+}
+
+static const struct clk_ops apll_ck_ops = {
+	.enable		= &dra7_apll_enable,
+	.disable	= &dra7_apll_disable,
+	.is_enabled	= &dra7_apll_is_enabled,
+	.get_parent	= &dra7_init_apll_parent,
+};
+
+static void __init omap_clk_register_apll(void *user,
+					  struct device_node *node)
+{
+	struct clk_hw *hw = user;
+	struct clk_hw_omap *clk_hw = to_clk_hw_omap(hw);
+	struct dpll_data *ad = clk_hw->dpll_data;
+	const char *name;
+	struct clk *clk;
+	const struct clk_init_data *init = clk_hw->hw.init;
+
+	clk = of_clk_get(node, 0);
+	if (IS_ERR(clk)) {
+		pr_debug("clk-ref for %pOFn not ready, retry\n",
+			 node);
+		if (!ti_clk_retry_init(node, hw, omap_clk_register_apll))
+			return;
+
+		goto cleanup;
+	}
+
+	ad->clk_ref = __clk_get_hw(clk);
+
+	clk = of_clk_get(node, 1);
+	if (IS_ERR(clk)) {
+		pr_debug("clk-bypass for %pOFn not ready, retry\n",
+			 node);
+		if (!ti_clk_retry_init(node, hw, omap_clk_register_apll))
+			return;
+
+		goto cleanup;
+	}
+
+	ad->clk_bypass = __clk_get_hw(clk);
+
+	name = ti_dt_clk_name(node);
+	clk = of_ti_clk_register_omap_hw(node, &clk_hw->hw, name);
+	if (!IS_ERR(clk)) {
+		of_clk_add_provider(node, of_clk_src_simple_get, clk);
+		kfree(init->parent_names);
+		kfree(init);
+		return;
+	}
+
+cleanup:
+	kfree(clk_hw->dpll_data);
+	kfree(init->parent_names);
+	kfree(init);
+	kfree(clk_hw);
+}
+
+static void __init of_dra7_apll_setup(struct device_node *node)
+{
+	struct dpll_data *ad = NULL;
+	struct clk_hw_omap *clk_hw = NULL;
+	struct clk_init_data *init = NULL;
+	const char **parent_names = NULL;
+	int ret;
+
+	ad = kzalloc_obj(*ad);
+	clk_hw = kzalloc_obj(*clk_hw);
+	init = kzalloc_obj(*init);
+	if (!ad || !clk_hw || !init)
+		goto cleanup;
+
+	clk_hw->dpll_data = ad;
+	clk_hw->hw.init = init;
+
+	init->name = ti_dt_clk_name(node);
+	init->ops = &apll_ck_ops;
+
+	init->num_parents = of_clk_get_parent_count(node);
+	if (init->num_parents < 1) {
+		pr_err("dra7 apll %pOFn must have parent(s)\n", node);
+		goto cleanup;
+	}
+
+	parent_names = kcalloc(init->num_parents, sizeof(char *), GFP_KERNEL);
+	if (!parent_names)
+		goto cleanup;
+
+	of_clk_parent_fill(node, parent_names, init->num_parents);
+
+	init->parent_names = parent_names;
+
+	ret = ti_clk_get_reg_addr(node, 0, &ad->control_reg);
+	ret |= ti_clk_get_reg_addr(node, 1, &ad->idlest_reg);
+
+	if (ret)
+		goto cleanup;
+
+	ad->idlest_mask = 0x1;
+	ad->enable_mask = 0x3;
+
+	omap_clk_register_apll(&clk_hw->hw, node);
+	return;
+
+cleanup:
+	kfree(parent_names);
+	kfree(ad);
+	kfree(clk_hw);
+	kfree(init);
+}
+CLK_OF_DECLARE(dra7_apll_clock, "ti,dra7-apll-clock", of_dra7_apll_setup);
+
+#define OMAP2_EN_APLL_LOCKED	0x3
+#define OMAP2_EN_APLL_STOPPED	0x0
+
+static int omap2_apll_is_enabled(struct clk_hw *hw)
+{
+	struct clk_hw_omap *clk = to_clk_hw_omap(hw);
+	struct dpll_data *ad = clk->dpll_data;
+	u32 v;
+
+	v = ti_clk_ll_ops->clk_readl(&ad->control_reg);
+	v &= ad->enable_mask;
+
+	v >>= __ffs(ad->enable_mask);
+
+	return v == OMAP2_EN_APLL_LOCKED ? 1 : 0;
+}
+
+static unsigned long omap2_apll_recalc(struct clk_hw *hw,
+				       unsigned long parent_rate)
+{
+	struct clk_hw_omap *clk = to_clk_hw_omap(hw);
+
+	if (omap2_apll_is_enabled(hw))
+		return clk->fixed_rate;
+
+	return 0;
+}
+
+static int omap2_apll_enable(struct clk_hw *hw)
+{
+	struct clk_hw_omap *clk = to_clk_hw_omap(hw);
+	struct dpll_data *ad = clk->dpll_data;
+	u32 v;
+	int i = 0;
+
+	v = ti_clk_ll_ops->clk_readl(&ad->control_reg);
+	v &= ~ad->enable_mask;
+	v |= OMAP2_EN_APLL_LOCKED << __ffs(ad->enable_mask);
+	ti_clk_ll_ops->clk_writel(v, &ad->control_reg);
+
+	while (1) {
+		v = ti_clk_ll_ops->clk_readl(&ad->idlest_reg);
+		if (v & ad->idlest_mask)
+			break;
+		if (i > MAX_APLL_WAIT_TRIES)
+			break;
+		i++;
+		udelay(1);
+	}
+
+	if (i == MAX_APLL_WAIT_TRIES) {
+		pr_warn("%s failed to transition to locked\n",
+			clk_hw_get_name(&clk->hw));
+		return -EBUSY;
+	}
+
+	return 0;
+}
+
+static void omap2_apll_disable(struct clk_hw *hw)
+{
+	struct clk_hw_omap *clk = to_clk_hw_omap(hw);
+	struct dpll_data *ad = clk->dpll_data;
+	u32 v;
+
+	v = ti_clk_ll_ops->clk_readl(&ad->control_reg);
+	v &= ~ad->enable_mask;
+	v |= OMAP2_EN_APLL_STOPPED << __ffs(ad->enable_mask);
+	ti_clk_ll_ops->clk_writel(v, &ad->control_reg);
+}
+
+static const struct clk_ops omap2_apll_ops = {
+	.enable		= &omap2_apll_enable,
+	.disable	= &omap2_apll_disable,
+	.is_enabled	= &omap2_apll_is_enabled,
+	.recalc_rate	= &omap2_apll_recalc,
+};
+
+static void omap2_apll_set_autoidle(struct clk_hw_omap *clk, u32 val)
+{
+	struct dpll_data *ad = clk->dpll_data;
+	u32 v;
+
+	v = ti_clk_ll_ops->clk_readl(&ad->autoidle_reg);
+	v &= ~ad->autoidle_mask;
+	v |= val << __ffs(ad->autoidle_mask);
+	ti_clk_ll_ops->clk_writel(v, &ad->control_reg);
+}
+
+#define OMAP2_APLL_AUTOIDLE_LOW_POWER_STOP	0x3
+#define OMAP2_APLL_AUTOIDLE_DISABLE		0x0
+
+static void omap2_apll_allow_idle(struct clk_hw_omap *clk)
+{
+	omap2_apll_set_autoidle(clk, OMAP2_APLL_AUTOIDLE_LOW_POWER_STOP);
+}
+
+static void omap2_apll_deny_idle(struct clk_hw_omap *clk)
+{
+	omap2_apll_set_autoidle(clk, OMAP2_APLL_AUTOIDLE_DISABLE);
+}
+
+static const struct clk_hw_omap_ops omap2_apll_hwops = {
+	.allow_idle	= &omap2_apll_allow_idle,
+	.deny_idle	= &omap2_apll_deny_idle,
+};
+
+static void __init of_omap2_apll_setup(struct device_node *node)
+{
+	struct dpll_data *ad = NULL;
+	struct clk_hw_omap *clk_hw = NULL;
+	struct clk_init_data *init = NULL;
+	const char *name;
+	struct clk *clk;
+	const char *parent_name;
+	u32 val;
+	int ret;
+
+	ad = kzalloc_obj(*ad);
+	clk_hw = kzalloc_obj(*clk_hw);
+	init = kzalloc_obj(*init);
+
+	if (!ad || !clk_hw || !init)
+		goto cleanup;
+
+	clk_hw->dpll_data = ad;
+	clk_hw->hw.init = init;
+	init->ops = &omap2_apll_ops;
+	name = ti_dt_clk_name(node);
+	init->name = name;
+	clk_hw->ops = &omap2_apll_hwops;
+
+	init->num_parents = of_clk_get_parent_count(node);
+	if (init->num_parents != 1) {
+		pr_err("%pOFn must have one parent\n", node);
+		goto cleanup;
+	}
+
+	parent_name = of_clk_get_parent_name(node, 0);
+	init->parent_names = &parent_name;
+
+	if (of_property_read_u32(node, "ti,clock-frequency", &val)) {
+		pr_err("%pOFn missing clock-frequency\n", node);
+		goto cleanup;
+	}
+	clk_hw->fixed_rate = val;
+
+	clk_hw->enable_bit = ti_clk_get_legacy_bit_shift(node);
+	ad->enable_mask = 0x3 << clk_hw->enable_bit;
+	ad->autoidle_mask = 0x3 << clk_hw->enable_bit;
+
+	if (of_property_read_u32(node, "ti,idlest-shift", &val)) {
+		pr_err("%pOFn missing idlest-shift\n", node);
+		goto cleanup;
+	}
+
+	ad->idlest_mask = 1 << val;
+
+	ret = ti_clk_get_reg_addr(node, 0, &ad->control_reg);
+	ret |= ti_clk_get_reg_addr(node, 1, &ad->autoidle_reg);
+	ret |= ti_clk_get_reg_addr(node, 2, &ad->idlest_reg);
+
+	if (ret)
+		goto cleanup;
+
+	name = ti_dt_clk_name(node);
+	clk = of_ti_clk_register_omap_hw(node, &clk_hw->hw, name);
+	if (!IS_ERR(clk)) {
+		of_clk_add_provider(node, of_clk_src_simple_get, clk);
+		kfree(init);
+		return;
+	}
+cleanup:
+	kfree(ad);
+	kfree(clk_hw);
+	kfree(init);
+}
+CLK_OF_DECLARE(omap2_apll_clock, "ti,omap2-apll-clock",
+	       of_omap2_apll_setup);