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, 304 insertions, 0 deletions

diff --git a/drivers/dma/txx9dmac.h b/drivers/dma/txx9dmac.h
new file mode 100644
index 000000000..aa53eafb1
--- /dev/null
+++ b/drivers/dma/txx9dmac.h
@@ -0,0 +1,304 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Driver for the TXx9 SoC DMA Controller
+ *
+ * Copyright (C) 2009 Atsushi Nemoto
+ */
+#ifndef TXX9DMAC_H
+#define TXX9DMAC_H
+
+#include <linux/dmaengine.h>
+#include <asm/txx9/dmac.h>
+
+/*
+ * Design Notes:
+ *
+ * This DMAC have four channels and one FIFO buffer.  Each channel can
+ * be configured for memory-memory or device-memory transfer, but only
+ * one channel can do alignment-free memory-memory transfer at a time
+ * while the channel should occupy the FIFO buffer for effective
+ * transfers.
+ *
+ * Instead of dynamically assign the FIFO buffer to channels, I chose
+ * make one dedicated channel for memory-memory transfer.  The
+ * dedicated channel is public.  Other channels are private and used
+ * for slave transfer.  Some devices in the SoC are wired to certain
+ * DMA channel.
+ */
+
+#ifdef CONFIG_MACH_TX49XX
+static inline bool txx9_dma_have_SMPCHN(void)
+{
+	return true;
+}
+#define TXX9_DMA_USE_SIMPLE_CHAIN
+#else
+static inline bool txx9_dma_have_SMPCHN(void)
+{
+	return false;
+}
+#endif
+
+#ifdef __LITTLE_ENDIAN
+#ifdef CONFIG_MACH_TX49XX
+#define CCR_LE	TXX9_DMA_CCR_LE
+#define MCR_LE	0
+#else
+#define CCR_LE	0
+#define MCR_LE	TXX9_DMA_MCR_LE
+#endif
+#else
+#define CCR_LE	0
+#define MCR_LE	0
+#endif
+
+/*
+ * Redefine this macro to handle differences between 32- and 64-bit
+ * addressing, big vs. little endian, etc.
+ */
+#ifdef __BIG_ENDIAN
+#define TXX9_DMA_REG32(name)		u32 __pad_##name; u32 name
+#else
+#define TXX9_DMA_REG32(name)		u32 name; u32 __pad_##name
+#endif
+
+/* Hardware register definitions. */
+struct txx9dmac_cregs {
+#if defined(CONFIG_32BIT) && !defined(CONFIG_PHYS_ADDR_T_64BIT)
+	TXX9_DMA_REG32(CHAR);	/* Chain Address Register */
+#else
+	u64 CHAR;		/* Chain Address Register */
+#endif
+	u64 SAR;		/* Source Address Register */
+	u64 DAR;		/* Destination Address Register */
+	TXX9_DMA_REG32(CNTR);	/* Count Register */
+	TXX9_DMA_REG32(SAIR);	/* Source Address Increment Register */
+	TXX9_DMA_REG32(DAIR);	/* Destination Address Increment Register */
+	TXX9_DMA_REG32(CCR);	/* Channel Control Register */
+	TXX9_DMA_REG32(CSR);	/* Channel Status Register */
+};
+struct txx9dmac_cregs32 {
+	u32 CHAR;
+	u32 SAR;
+	u32 DAR;
+	u32 CNTR;
+	u32 SAIR;
+	u32 DAIR;
+	u32 CCR;
+	u32 CSR;
+};
+
+struct txx9dmac_regs {
+	/* per-channel registers */
+	struct txx9dmac_cregs	CHAN[TXX9_DMA_MAX_NR_CHANNELS];
+	u64	__pad[9];
+	u64	MFDR;		/* Memory Fill Data Register */
+	TXX9_DMA_REG32(MCR);	/* Master Control Register */
+};
+struct txx9dmac_regs32 {
+	struct txx9dmac_cregs32	CHAN[TXX9_DMA_MAX_NR_CHANNELS];
+	u32	__pad[9];
+	u32	MFDR;
+	u32	MCR;
+};
+
+/* bits for MCR */
+#define TXX9_DMA_MCR_EIS(ch)	(0x10000000<<(ch))
+#define TXX9_DMA_MCR_DIS(ch)	(0x01000000<<(ch))
+#define TXX9_DMA_MCR_RSFIF	0x00000080
+#define TXX9_DMA_MCR_FIFUM(ch)	(0x00000008<<(ch))
+#define TXX9_DMA_MCR_LE		0x00000004
+#define TXX9_DMA_MCR_RPRT	0x00000002
+#define TXX9_DMA_MCR_MSTEN	0x00000001
+
+/* bits for CCRn */
+#define TXX9_DMA_CCR_IMMCHN	0x20000000
+#define TXX9_DMA_CCR_USEXFSZ	0x10000000
+#define TXX9_DMA_CCR_LE		0x08000000
+#define TXX9_DMA_CCR_DBINH	0x04000000
+#define TXX9_DMA_CCR_SBINH	0x02000000
+#define TXX9_DMA_CCR_CHRST	0x01000000
+#define TXX9_DMA_CCR_RVBYTE	0x00800000
+#define TXX9_DMA_CCR_ACKPOL	0x00400000
+#define TXX9_DMA_CCR_REQPL	0x00200000
+#define TXX9_DMA_CCR_EGREQ	0x00100000
+#define TXX9_DMA_CCR_CHDN	0x00080000
+#define TXX9_DMA_CCR_DNCTL	0x00060000
+#define TXX9_DMA_CCR_EXTRQ	0x00010000
+#define TXX9_DMA_CCR_INTRQD	0x0000e000
+#define TXX9_DMA_CCR_INTENE	0x00001000
+#define TXX9_DMA_CCR_INTENC	0x00000800
+#define TXX9_DMA_CCR_INTENT	0x00000400
+#define TXX9_DMA_CCR_CHNEN	0x00000200
+#define TXX9_DMA_CCR_XFACT	0x00000100
+#define TXX9_DMA_CCR_SMPCHN	0x00000020
+#define TXX9_DMA_CCR_XFSZ(order)	(((order) << 2) & 0x0000001c)
+#define TXX9_DMA_CCR_XFSZ_1	TXX9_DMA_CCR_XFSZ(0)
+#define TXX9_DMA_CCR_XFSZ_2	TXX9_DMA_CCR_XFSZ(1)
+#define TXX9_DMA_CCR_XFSZ_4	TXX9_DMA_CCR_XFSZ(2)
+#define TXX9_DMA_CCR_XFSZ_8	TXX9_DMA_CCR_XFSZ(3)
+#define TXX9_DMA_CCR_XFSZ_X4	TXX9_DMA_CCR_XFSZ(4)
+#define TXX9_DMA_CCR_XFSZ_X8	TXX9_DMA_CCR_XFSZ(5)
+#define TXX9_DMA_CCR_XFSZ_X16	TXX9_DMA_CCR_XFSZ(6)
+#define TXX9_DMA_CCR_XFSZ_X32	TXX9_DMA_CCR_XFSZ(7)
+#define TXX9_DMA_CCR_MEMIO	0x00000002
+#define TXX9_DMA_CCR_SNGAD	0x00000001
+
+/* bits for CSRn */
+#define TXX9_DMA_CSR_CHNEN	0x00000400
+#define TXX9_DMA_CSR_STLXFER	0x00000200
+#define TXX9_DMA_CSR_XFACT	0x00000100
+#define TXX9_DMA_CSR_ABCHC	0x00000080
+#define TXX9_DMA_CSR_NCHNC	0x00000040
+#define TXX9_DMA_CSR_NTRNFC	0x00000020
+#define TXX9_DMA_CSR_EXTDN	0x00000010
+#define TXX9_DMA_CSR_CFERR	0x00000008
+#define TXX9_DMA_CSR_CHERR	0x00000004
+#define TXX9_DMA_CSR_DESERR	0x00000002
+#define TXX9_DMA_CSR_SORERR	0x00000001
+
+struct txx9dmac_chan {
+	struct dma_chan		chan;
+	struct dma_device	dma;
+	struct txx9dmac_dev	*ddev;
+	void __iomem		*ch_regs;
+	struct tasklet_struct	tasklet;
+	int			irq;
+	u32			ccr;
+
+	spinlock_t		lock;
+
+	/* these other elements are all protected by lock */
+	struct list_head	active_list;
+	struct list_head	queue;
+	struct list_head	free_list;
+
+	unsigned int		descs_allocated;
+};
+
+struct txx9dmac_dev {
+	void __iomem		*regs;
+	struct tasklet_struct	tasklet;
+	int			irq;
+	struct txx9dmac_chan	*chan[TXX9_DMA_MAX_NR_CHANNELS];
+	bool			have_64bit_regs;
+	unsigned int		descsize;
+};
+
+static inline bool __is_dmac64(const struct txx9dmac_dev *ddev)
+{
+	return ddev->have_64bit_regs;
+}
+
+static inline bool is_dmac64(const struct txx9dmac_chan *dc)
+{
+	return __is_dmac64(dc->ddev);
+}
+
+#ifdef TXX9_DMA_USE_SIMPLE_CHAIN
+/* Hardware descriptor definition. (for simple-chain) */
+struct txx9dmac_hwdesc {
+#if defined(CONFIG_32BIT) && !defined(CONFIG_PHYS_ADDR_T_64BIT)
+	TXX9_DMA_REG32(CHAR);
+#else
+	u64 CHAR;
+#endif
+	u64 SAR;
+	u64 DAR;
+	TXX9_DMA_REG32(CNTR);
+};
+struct txx9dmac_hwdesc32 {
+	u32 CHAR;
+	u32 SAR;
+	u32 DAR;
+	u32 CNTR;
+};
+#else
+#define txx9dmac_hwdesc txx9dmac_cregs
+#define txx9dmac_hwdesc32 txx9dmac_cregs32
+#endif
+
+struct txx9dmac_desc {
+	/* FIRST values the hardware uses */
+	union {
+		struct txx9dmac_hwdesc hwdesc;
+		struct txx9dmac_hwdesc32 hwdesc32;
+	};
+
+	/* THEN values for driver housekeeping */
+	struct list_head		desc_node ____cacheline_aligned;
+	struct list_head		tx_list;
+	struct dma_async_tx_descriptor	txd;
+	size_t				len;
+};
+
+#ifdef TXX9_DMA_USE_SIMPLE_CHAIN
+
+static inline bool txx9dmac_chan_INTENT(struct txx9dmac_chan *dc)
+{
+	return (dc->ccr & TXX9_DMA_CCR_INTENT) != 0;
+}
+
+static inline void txx9dmac_chan_set_INTENT(struct txx9dmac_chan *dc)
+{
+	dc->ccr |= TXX9_DMA_CCR_INTENT;
+}
+
+static inline void txx9dmac_desc_set_INTENT(struct txx9dmac_dev *ddev,
+					    struct txx9dmac_desc *desc)
+{
+}
+
+static inline void txx9dmac_chan_set_SMPCHN(struct txx9dmac_chan *dc)
+{
+	dc->ccr |= TXX9_DMA_CCR_SMPCHN;
+}
+
+static inline void txx9dmac_desc_set_nosimple(struct txx9dmac_dev *ddev,
+					      struct txx9dmac_desc *desc,
+					      u32 sair, u32 dair, u32 ccr)
+{
+}
+
+#else /* TXX9_DMA_USE_SIMPLE_CHAIN */
+
+static inline bool txx9dmac_chan_INTENT(struct txx9dmac_chan *dc)
+{
+	return true;
+}
+
+static void txx9dmac_chan_set_INTENT(struct txx9dmac_chan *dc)
+{
+}
+
+static inline void txx9dmac_desc_set_INTENT(struct txx9dmac_dev *ddev,
+					    struct txx9dmac_desc *desc)
+{
+	if (__is_dmac64(ddev))
+		desc->hwdesc.CCR |= TXX9_DMA_CCR_INTENT;
+	else
+		desc->hwdesc32.CCR |= TXX9_DMA_CCR_INTENT;
+}
+
+static inline void txx9dmac_chan_set_SMPCHN(struct txx9dmac_chan *dc)
+{
+}
+
+static inline void txx9dmac_desc_set_nosimple(struct txx9dmac_dev *ddev,
+					      struct txx9dmac_desc *desc,
+					      u32 sai, u32 dai, u32 ccr)
+{
+	if (__is_dmac64(ddev)) {
+		desc->hwdesc.SAIR = sai;
+		desc->hwdesc.DAIR = dai;
+		desc->hwdesc.CCR = ccr;
+	} else {
+		desc->hwdesc32.SAIR = sai;
+		desc->hwdesc32.DAIR = dai;
+		desc->hwdesc32.CCR = ccr;
+	}
+}
+
+#endif /* TXX9_DMA_USE_SIMPLE_CHAIN */
+
+#endif /* TXX9DMAC_H */