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, 263 insertions, 0 deletions

diff --git a/drivers/clk/sprd/pll.c b/drivers/clk/sprd/pll.c
new file mode 100644
index 000000000..4aec30777
--- /dev/null
+++ b/drivers/clk/sprd/pll.c
@@ -0,0 +1,263 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Spreadtrum pll clock driver
+//
+// Copyright (C) 2015~2017 Spreadtrum, Inc.
+// Author: Chunyan Zhang <chunyan.zhang@spreadtrum.com>
+
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+#include "pll.h"
+
+#define CLK_PLL_1M	1000000
+#define CLK_PLL_10M	(CLK_PLL_1M * 10)
+
+#define pindex(pll, member)		\
+	(pll->factors[member].shift / (8 * sizeof(pll->regs_num)))
+
+#define pshift(pll, member)		\
+	(pll->factors[member].shift % (8 * sizeof(pll->regs_num)))
+
+#define pwidth(pll, member)		\
+	pll->factors[member].width
+
+#define pmask(pll, member)					\
+	((pwidth(pll, member)) ?				\
+	GENMASK(pwidth(pll, member) + pshift(pll, member) - 1,	\
+	pshift(pll, member)) : 0)
+
+#define pinternal(pll, cfg, member)	\
+	(cfg[pindex(pll, member)] & pmask(pll, member))
+
+#define pinternal_val(pll, cfg, member)	\
+	(pinternal(pll, cfg, member) >> pshift(pll, member))
+
+static inline unsigned int
+sprd_pll_read(const struct sprd_pll *pll, u8 index)
+{
+	const struct sprd_clk_common *common = &pll->common;
+	unsigned int val = 0;
+
+	if (WARN_ON(index >= pll->regs_num))
+		return 0;
+
+	regmap_read(common->regmap, common->reg + index * 4, &val);
+
+	return val;
+}
+
+static inline void
+sprd_pll_write(const struct sprd_pll *pll, u8 index,
+				  u32 msk, u32 val)
+{
+	const struct sprd_clk_common *common = &pll->common;
+	unsigned int offset, reg;
+	int ret = 0;
+
+	if (WARN_ON(index >= pll->regs_num))
+		return;
+
+	offset = common->reg + index * 4;
+	ret = regmap_read(common->regmap, offset, &reg);
+	if (!ret)
+		regmap_write(common->regmap, offset, (reg & ~msk) | val);
+}
+
+static unsigned long pll_get_refin(const struct sprd_pll *pll)
+{
+	u32 shift, mask, index, refin_id = 3;
+	const unsigned long refin[4] = { 2, 4, 13, 26 };
+
+	if (pwidth(pll, PLL_REFIN)) {
+		index = pindex(pll, PLL_REFIN);
+		shift = pshift(pll, PLL_REFIN);
+		mask = pmask(pll, PLL_REFIN);
+		refin_id = (sprd_pll_read(pll, index) & mask) >> shift;
+		if (refin_id > 3)
+			refin_id = 3;
+	}
+
+	return refin[refin_id];
+}
+
+static u32 pll_get_ibias(u64 rate, const u64 *table)
+{
+	u32 i, num = table[0];
+
+	/* table[0] indicates the number of items in this table */
+	for (i = 0; i < num; i++)
+		if (rate <= table[i + 1])
+			break;
+
+	return i == num ? num - 1 : i;
+}
+
+static unsigned long _sprd_pll_recalc_rate(const struct sprd_pll *pll,
+					   unsigned long parent_rate)
+{
+	u32 *cfg;
+	u32 i, mask, regs_num = pll->regs_num;
+	unsigned long rate, nint, kint = 0;
+	u64 refin;
+	u16 k1, k2;
+
+	cfg = kcalloc(regs_num, sizeof(*cfg), GFP_KERNEL);
+	if (!cfg)
+		return parent_rate;
+
+	for (i = 0; i < regs_num; i++)
+		cfg[i] = sprd_pll_read(pll, i);
+
+	refin = pll_get_refin(pll);
+
+	if (pinternal(pll, cfg, PLL_PREDIV))
+		refin = refin * 2;
+
+	if (pwidth(pll, PLL_POSTDIV) &&
+	    ((pll->fflag == 1 && pinternal(pll, cfg, PLL_POSTDIV)) ||
+	     (!pll->fflag && !pinternal(pll, cfg, PLL_POSTDIV))))
+		refin = refin / 2;
+
+	if (!pinternal(pll, cfg, PLL_DIV_S)) {
+		rate = refin * pinternal_val(pll, cfg, PLL_N) * CLK_PLL_10M;
+	} else {
+		nint = pinternal_val(pll, cfg, PLL_NINT);
+		if (pinternal(pll, cfg, PLL_SDM_EN))
+			kint = pinternal_val(pll, cfg, PLL_KINT);
+
+		mask = pmask(pll, PLL_KINT);
+
+		k1 = pll->k1;
+		k2 = pll->k2;
+		rate = DIV_ROUND_CLOSEST_ULL(refin * kint * k1,
+					 ((mask >> __ffs(mask)) + 1)) *
+					 k2 + refin * nint * CLK_PLL_1M;
+	}
+
+	kfree(cfg);
+	return rate;
+}
+
+#define SPRD_PLL_WRITE_CHECK(pll, i, mask, val)		\
+	(((sprd_pll_read(pll, i) & mask) == val) ? 0 : (-EFAULT))
+
+static int _sprd_pll_set_rate(const struct sprd_pll *pll,
+			      unsigned long rate,
+			      unsigned long parent_rate)
+{
+	struct reg_cfg *cfg;
+	int ret = 0;
+	u32 mask, shift, width, ibias_val, index;
+	u32 regs_num = pll->regs_num, i = 0;
+	unsigned long kint, nint;
+	u64 tmp, refin, fvco = rate;
+
+	cfg = kzalloc_objs(*cfg, regs_num);
+	if (!cfg)
+		return -ENOMEM;
+
+	refin = pll_get_refin(pll);
+
+	mask = pmask(pll, PLL_PREDIV);
+	index = pindex(pll, PLL_PREDIV);
+	width = pwidth(pll, PLL_PREDIV);
+	if (width && (sprd_pll_read(pll, index) & mask))
+		refin = refin * 2;
+
+	mask = pmask(pll, PLL_POSTDIV);
+	index = pindex(pll, PLL_POSTDIV);
+	width = pwidth(pll, PLL_POSTDIV);
+	cfg[index].msk = mask;
+	if (width && ((pll->fflag == 1 && fvco <= pll->fvco) ||
+		      (pll->fflag == 0 && fvco > pll->fvco)))
+		cfg[index].val |= mask;
+
+	if (width && fvco <= pll->fvco)
+		fvco = fvco * 2;
+
+	mask = pmask(pll, PLL_DIV_S);
+	index = pindex(pll, PLL_DIV_S);
+	cfg[index].val |= mask;
+	cfg[index].msk |= mask;
+
+	mask = pmask(pll, PLL_SDM_EN);
+	index = pindex(pll, PLL_SDM_EN);
+	cfg[index].val |= mask;
+	cfg[index].msk |= mask;
+
+	nint = do_div(fvco, refin * CLK_PLL_1M);
+	mask = pmask(pll, PLL_NINT);
+	index = pindex(pll, PLL_NINT);
+	shift = pshift(pll, PLL_NINT);
+	cfg[index].val |= (nint << shift) & mask;
+	cfg[index].msk |= mask;
+
+	mask = pmask(pll, PLL_KINT);
+	index = pindex(pll, PLL_KINT);
+	width = pwidth(pll, PLL_KINT);
+	shift = pshift(pll, PLL_KINT);
+	tmp = fvco - refin * nint * CLK_PLL_1M;
+	tmp = do_div(tmp, 10000) * ((mask >> shift) + 1);
+	kint = DIV_ROUND_CLOSEST_ULL(tmp, refin * 100);
+	cfg[index].val |= (kint << shift) & mask;
+	cfg[index].msk |= mask;
+
+	ibias_val = pll_get_ibias(fvco, pll->itable);
+
+	mask = pmask(pll, PLL_IBIAS);
+	index = pindex(pll, PLL_IBIAS);
+	shift = pshift(pll, PLL_IBIAS);
+	cfg[index].val |= ibias_val << shift & mask;
+	cfg[index].msk |= mask;
+
+	for (i = 0; i < regs_num; i++) {
+		if (cfg[i].msk) {
+			sprd_pll_write(pll, i, cfg[i].msk, cfg[i].val);
+			ret |= SPRD_PLL_WRITE_CHECK(pll, i, cfg[i].msk,
+						   cfg[i].val);
+		}
+	}
+
+	if (!ret)
+		udelay(pll->udelay);
+
+	kfree(cfg);
+	return ret;
+}
+
+static unsigned long sprd_pll_recalc_rate(struct clk_hw *hw,
+					  unsigned long parent_rate)
+{
+	struct sprd_pll *pll = hw_to_sprd_pll(hw);
+
+	return _sprd_pll_recalc_rate(pll, parent_rate);
+}
+
+static int sprd_pll_set_rate(struct clk_hw *hw,
+			     unsigned long rate,
+			     unsigned long parent_rate)
+{
+	struct sprd_pll *pll = hw_to_sprd_pll(hw);
+
+	return _sprd_pll_set_rate(pll, rate, parent_rate);
+}
+
+static int sprd_pll_clk_prepare(struct clk_hw *hw)
+{
+	struct sprd_pll *pll = hw_to_sprd_pll(hw);
+
+	udelay(pll->udelay);
+
+	return 0;
+}
+
+const struct clk_ops sprd_pll_ops = {
+	.prepare = sprd_pll_clk_prepare,
+	.recalc_rate = sprd_pll_recalc_rate,
+	.determine_rate = clk_determine_rate_noop,
+	.set_rate = sprd_pll_set_rate,
+};
+EXPORT_SYMBOL_GPL(sprd_pll_ops);