From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops 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 --- drivers/clk/sprd/gate.c | 135 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 135 insertions(+) create mode 100644 drivers/clk/sprd/gate.c (limited to 'drivers/clk/sprd/gate.c') diff --git a/drivers/clk/sprd/gate.c b/drivers/clk/sprd/gate.c new file mode 100644 index 000000000..56e1714b5 --- /dev/null +++ b/drivers/clk/sprd/gate.c @@ -0,0 +1,135 @@ +// SPDX-License-Identifier: GPL-2.0 +// +// Spreadtrum gate clock driver +// +// Copyright (C) 2017 Spreadtrum, Inc. +// Author: Chunyan Zhang + +#include +#include + +#include "gate.h" + +static void clk_gate_toggle(const struct sprd_gate *sg, bool en) +{ + const struct sprd_clk_common *common = &sg->common; + unsigned int reg; + bool set = sg->flags & CLK_GATE_SET_TO_DISABLE ? true : false; + + set ^= en; + + regmap_read(common->regmap, common->reg, ®); + + if (set) + reg |= sg->enable_mask; + else + reg &= ~sg->enable_mask; + + regmap_write(common->regmap, common->reg, reg); +} + +static void clk_sc_gate_toggle(const struct sprd_gate *sg, bool en) +{ + const struct sprd_clk_common *common = &sg->common; + bool set = sg->flags & CLK_GATE_SET_TO_DISABLE ? 1 : 0; + unsigned int offset; + + set ^= en; + + /* + * Each set/clear gate clock has three registers: + * common->reg - base register + * common->reg + offset - set register + * common->reg + 2 * offset - clear register + */ + offset = set ? sg->sc_offset : sg->sc_offset * 2; + + regmap_write(common->regmap, common->reg + offset, + sg->enable_mask); +} + +static void sprd_gate_disable(struct clk_hw *hw) +{ + struct sprd_gate *sg = hw_to_sprd_gate(hw); + + clk_gate_toggle(sg, false); +} + +static int sprd_gate_enable(struct clk_hw *hw) +{ + struct sprd_gate *sg = hw_to_sprd_gate(hw); + + clk_gate_toggle(sg, true); + + return 0; +} + +static void sprd_sc_gate_disable(struct clk_hw *hw) +{ + struct sprd_gate *sg = hw_to_sprd_gate(hw); + + clk_sc_gate_toggle(sg, false); +} + +static int sprd_sc_gate_enable(struct clk_hw *hw) +{ + struct sprd_gate *sg = hw_to_sprd_gate(hw); + + clk_sc_gate_toggle(sg, true); + + return 0; +} + +static int sprd_pll_sc_gate_prepare(struct clk_hw *hw) +{ + struct sprd_gate *sg = hw_to_sprd_gate(hw); + + clk_sc_gate_toggle(sg, true); + udelay(sg->udelay); + + return 0; +} + +static int sprd_gate_is_enabled(struct clk_hw *hw) +{ + struct sprd_gate *sg = hw_to_sprd_gate(hw); + struct sprd_clk_common *common = &sg->common; + struct clk_hw *parent; + unsigned int reg; + + if (sg->flags & SPRD_GATE_NON_AON) { + parent = clk_hw_get_parent(hw); + if (!parent || !clk_hw_is_enabled(parent)) + return 0; + } + + regmap_read(common->regmap, common->reg, ®); + + if (sg->flags & CLK_GATE_SET_TO_DISABLE) + reg ^= sg->enable_mask; + + reg &= sg->enable_mask; + + return reg ? 1 : 0; +} + +const struct clk_ops sprd_gate_ops = { + .disable = sprd_gate_disable, + .enable = sprd_gate_enable, + .is_enabled = sprd_gate_is_enabled, +}; +EXPORT_SYMBOL_GPL(sprd_gate_ops); + +const struct clk_ops sprd_sc_gate_ops = { + .disable = sprd_sc_gate_disable, + .enable = sprd_sc_gate_enable, + .is_enabled = sprd_gate_is_enabled, +}; +EXPORT_SYMBOL_GPL(sprd_sc_gate_ops); + +const struct clk_ops sprd_pll_sc_gate_ops = { + .unprepare = sprd_sc_gate_disable, + .prepare = sprd_pll_sc_gate_prepare, + .is_enabled = sprd_gate_is_enabled, +}; +EXPORT_SYMBOL_GPL(sprd_pll_sc_gate_ops); -- cgit v1.3.1