x86/kprobes: Fix crash when probing CS CALL instructionsgrafted

When using eBPF to probe CS CALL instructions within a function,
a crash can be triggered.

The eBPF tool probes offset 257 of the __hrtimer_run_queues()
function:

<__hrtimer_run_queues+249>:  nopl   0x0(%rax,%rax,1)
<__hrtimer_run_queues+254>:  mov    %r14,%rdi
<__hrtimer_run_queues+257>:  cs call <__x86_indirect_thunk_r12>
<__hrtimer_run_queues+263>:  mov    %eax,%r12d
<__hrtimer_run_queues+266>:  xchg   %ax,%ax
<__hrtimer_run_queues+268>:  mov    %r13,%rdi

Which triggers this crash:

  BUG: unable to handle page fault for address: 00000000000f41c9
  #PF: supervisor write access in kernel mode
  #PF: error_code(0x0002) - not-present page
  PGD 0 P4D 0
  Oops: 0002 [#1] SMP NOPTI
  CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P
  RIP: 0010:__hrtimer_run_queues+0x106/0x230

Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is
at the 6th byte of the above CS CALL instruction. Since the CS CALL
instruction occupies 6 bytes, the exception occurred in the middle of that
call instruction.

The root cause is that when using eBPF tools to probe in the middle of a
function, a kprobe with INT3 is used as the underlying implementation.

During single-step emulation of the original CALL instruction,
int3_emulate_call() assumes that the probed CALL instruction is 5 bytes
long. However, the actual CS-prefixed CALL instruction occupies 6 bytes,
so it constructs an incorrect exception return address. When the CPU
returns from the kprobe handler, the next instruction to be executed is at
the address of the last byte of that CS CALL instruction. Coincidentally,
starting from that address, the CPU fetches and decodes a completely
different instruction, which ultimately triggers a kernel crash.

Fix the issue by using the actual instruction length obtained from
the instruction decoder when constructing the exception return
address, rather than relying on the hardcoded CALL_INSN_SIZE macro.

[ mingo: Refined the changelog ]

Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step")
Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Jinke Han <jinkehan@didiglobal.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000

1 files changed, 426 insertions, 0 deletions

diff --git a/drivers/gpu/ipu-v3/ipu-dc.c b/drivers/gpu/ipu-v3/ipu-dc.c
new file mode 100644
index 000000000..b038a6d73
--- /dev/null
+++ b/drivers/gpu/ipu-v3/ipu-dc.c
@@ -0,0 +1,426 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2010 Sascha Hauer <s.hauer@pengutronix.de>
+ * Copyright (C) 2005-2009 Freescale Semiconductor, Inc.
+ */
+
+#include <linux/export.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+
+#include <video/imx-ipu-v3.h>
+#include "ipu-prv.h"
+
+#define DC_MAP_CONF_PTR(n)	(0x108 + ((n) & ~0x1) * 2)
+#define DC_MAP_CONF_VAL(n)	(0x144 + ((n) & ~0x1) * 2)
+
+#define DC_EVT_NF		0
+#define DC_EVT_NL		1
+#define DC_EVT_EOF		2
+#define DC_EVT_NFIELD		3
+#define DC_EVT_EOL		4
+#define DC_EVT_EOFIELD		5
+#define DC_EVT_NEW_ADDR		6
+#define DC_EVT_NEW_CHAN		7
+#define DC_EVT_NEW_DATA		8
+
+#define DC_EVT_NEW_ADDR_W_0	0
+#define DC_EVT_NEW_ADDR_W_1	1
+#define DC_EVT_NEW_CHAN_W_0	2
+#define DC_EVT_NEW_CHAN_W_1	3
+#define DC_EVT_NEW_DATA_W_0	4
+#define DC_EVT_NEW_DATA_W_1	5
+#define DC_EVT_NEW_ADDR_R_0	6
+#define DC_EVT_NEW_ADDR_R_1	7
+#define DC_EVT_NEW_CHAN_R_0	8
+#define DC_EVT_NEW_CHAN_R_1	9
+#define DC_EVT_NEW_DATA_R_0	10
+#define DC_EVT_NEW_DATA_R_1	11
+
+#define DC_WR_CH_CONF		0x0
+#define DC_WR_CH_ADDR		0x4
+#define DC_RL_CH(evt)		(8 + ((evt) & ~0x1) * 2)
+
+#define DC_GEN			0xd4
+#define DC_DISP_CONF1(disp)	(0xd8 + (disp) * 4)
+#define DC_DISP_CONF2(disp)	(0xe8 + (disp) * 4)
+#define DC_STAT			0x1c8
+
+#define WROD(lf)		(0x18 | ((lf) << 1))
+#define WRG			0x01
+#define WCLK			0xc9
+
+#define SYNC_WAVE 0
+#define NULL_WAVE (-1)
+
+#define DC_GEN_SYNC_1_6_SYNC	(2 << 1)
+#define DC_GEN_SYNC_PRIORITY_1	(1 << 7)
+
+#define DC_WR_CH_CONF_WORD_SIZE_8		(0 << 0)
+#define DC_WR_CH_CONF_WORD_SIZE_16		(1 << 0)
+#define DC_WR_CH_CONF_WORD_SIZE_24		(2 << 0)
+#define DC_WR_CH_CONF_WORD_SIZE_32		(3 << 0)
+#define DC_WR_CH_CONF_DISP_ID_PARALLEL(i)	(((i) & 0x1) << 3)
+#define DC_WR_CH_CONF_DISP_ID_SERIAL		(2 << 3)
+#define DC_WR_CH_CONF_DISP_ID_ASYNC		(3 << 4)
+#define DC_WR_CH_CONF_FIELD_MODE		(1 << 9)
+#define DC_WR_CH_CONF_PROG_TYPE_NORMAL		(4 << 5)
+#define DC_WR_CH_CONF_PROG_TYPE_MASK		(7 << 5)
+#define DC_WR_CH_CONF_PROG_DI_ID		(1 << 2)
+#define DC_WR_CH_CONF_PROG_DISP_ID(i)		(((i) & 0x1) << 3)
+
+#define IPU_DC_NUM_CHANNELS	10
+
+struct ipu_dc_priv;
+
+enum ipu_dc_map {
+	IPU_DC_MAP_RGB24,
+	IPU_DC_MAP_RGB565,
+	IPU_DC_MAP_GBR24, /* TVEv2 */
+	IPU_DC_MAP_BGR666,
+	IPU_DC_MAP_LVDS666,
+	IPU_DC_MAP_BGR24,
+};
+
+struct ipu_dc {
+	/* The display interface number assigned to this dc channel */
+	unsigned int		di;
+	void __iomem		*base;
+	struct ipu_dc_priv	*priv;
+	int			chno;
+	bool			in_use;
+};
+
+struct ipu_dc_priv {
+	void __iomem		*dc_reg;
+	void __iomem		*dc_tmpl_reg;
+	struct ipu_soc		*ipu;
+	struct device		*dev;
+	struct ipu_dc		channels[IPU_DC_NUM_CHANNELS];
+	struct mutex		mutex;
+	struct completion	comp;
+	int			use_count;
+};
+
+static void dc_link_event(struct ipu_dc *dc, int event, int addr, int priority)
+{
+	u32 reg;
+
+	reg = readl(dc->base + DC_RL_CH(event));
+	reg &= ~(0xffff << (16 * (event & 0x1)));
+	reg |= ((addr << 8) | priority) << (16 * (event & 0x1));
+	writel(reg, dc->base + DC_RL_CH(event));
+}
+
+static void dc_write_tmpl(struct ipu_dc *dc, int word, u32 opcode, u32 operand,
+		int map, int wave, int glue, int sync, int stop)
+{
+	struct ipu_dc_priv *priv = dc->priv;
+	u32 reg1, reg2;
+
+	if (opcode == WCLK) {
+		reg1 = (operand << 20) & 0xfff00000;
+		reg2 = operand >> 12 | opcode << 1 | stop << 9;
+	} else if (opcode == WRG) {
+		reg1 = sync | glue << 4 | ++wave << 11 | ((operand << 15) & 0xffff8000);
+		reg2 = operand >> 17 | opcode << 7 | stop << 9;
+	} else {
+		reg1 = sync | glue << 4 | ++wave << 11 | ++map << 15 | ((operand << 20) & 0xfff00000);
+		reg2 = operand >> 12 | opcode << 4 | stop << 9;
+	}
+	writel(reg1, priv->dc_tmpl_reg + word * 8);
+	writel(reg2, priv->dc_tmpl_reg + word * 8 + 4);
+}
+
+static int ipu_bus_format_to_map(u32 fmt)
+{
+	switch (fmt) {
+	default:
+		WARN_ON(1);
+		fallthrough;
+	case MEDIA_BUS_FMT_RGB888_1X24:
+		return IPU_DC_MAP_RGB24;
+	case MEDIA_BUS_FMT_RGB565_1X16:
+		return IPU_DC_MAP_RGB565;
+	case MEDIA_BUS_FMT_GBR888_1X24:
+		return IPU_DC_MAP_GBR24;
+	case MEDIA_BUS_FMT_RGB666_1X18:
+		return IPU_DC_MAP_BGR666;
+	case MEDIA_BUS_FMT_RGB666_1X24_CPADHI:
+		return IPU_DC_MAP_LVDS666;
+	case MEDIA_BUS_FMT_BGR888_1X24:
+		return IPU_DC_MAP_BGR24;
+	}
+}
+
+int ipu_dc_init_sync(struct ipu_dc *dc, struct ipu_di *di, bool interlaced,
+		u32 bus_format, u32 width)
+{
+	struct ipu_dc_priv *priv = dc->priv;
+	int addr, sync;
+	u32 reg = 0;
+	int map;
+
+	dc->di = ipu_di_get_num(di);
+
+	if (!IS_ALIGNED(width, 8)) {
+		dev_warn(priv->dev,
+			 "%s: hactive does not align to 8 byte\n", __func__);
+	}
+
+	map = ipu_bus_format_to_map(bus_format);
+
+	/*
+	 * In interlaced mode we need more counters to create the asymmetric
+	 * per-field VSYNC signals. The pixel active signal synchronising DC
+	 * to DI moves to signal generator #6 (see ipu-di.c). In progressive
+	 * mode counter #5 is used.
+	 */
+	sync = interlaced ? 6 : 5;
+
+	/* Reserve 5 microcode template words for each DI */
+	if (dc->di)
+		addr = 5;
+	else
+		addr = 0;
+
+	if (interlaced) {
+		dc_link_event(dc, DC_EVT_NL, addr, 3);
+		dc_link_event(dc, DC_EVT_EOL, addr, 2);
+		dc_link_event(dc, DC_EVT_NEW_DATA, addr, 1);
+
+		/* Init template microcode */
+		dc_write_tmpl(dc, addr, WROD(0), 0, map, SYNC_WAVE, 0, sync, 1);
+	} else {
+		dc_link_event(dc, DC_EVT_NL, addr + 2, 3);
+		dc_link_event(dc, DC_EVT_EOL, addr + 3, 2);
+		dc_link_event(dc, DC_EVT_NEW_DATA, addr + 1, 1);
+
+		/* Init template microcode */
+		dc_write_tmpl(dc, addr + 2, WROD(0), 0, map, SYNC_WAVE, 8, sync, 1);
+		dc_write_tmpl(dc, addr + 3, WROD(0), 0, map, SYNC_WAVE, 4, sync, 0);
+		dc_write_tmpl(dc, addr + 4, WRG, 0, map, NULL_WAVE, 0, 0, 1);
+		dc_write_tmpl(dc, addr + 1, WROD(0), 0, map, SYNC_WAVE, 0, sync, 1);
+	}
+
+	dc_link_event(dc, DC_EVT_NF, 0, 0);
+	dc_link_event(dc, DC_EVT_NFIELD, 0, 0);
+	dc_link_event(dc, DC_EVT_EOF, 0, 0);
+	dc_link_event(dc, DC_EVT_EOFIELD, 0, 0);
+	dc_link_event(dc, DC_EVT_NEW_CHAN, 0, 0);
+	dc_link_event(dc, DC_EVT_NEW_ADDR, 0, 0);
+
+	reg = readl(dc->base + DC_WR_CH_CONF);
+	if (interlaced)
+		reg |= DC_WR_CH_CONF_FIELD_MODE;
+	else
+		reg &= ~DC_WR_CH_CONF_FIELD_MODE;
+	writel(reg, dc->base + DC_WR_CH_CONF);
+
+	writel(0x0, dc->base + DC_WR_CH_ADDR);
+	writel(width, priv->dc_reg + DC_DISP_CONF2(dc->di));
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(ipu_dc_init_sync);
+
+void ipu_dc_enable(struct ipu_soc *ipu)
+{
+	struct ipu_dc_priv *priv = ipu->dc_priv;
+
+	mutex_lock(&priv->mutex);
+
+	if (!priv->use_count)
+		ipu_module_enable(priv->ipu, IPU_CONF_DC_EN);
+
+	priv->use_count++;
+
+	mutex_unlock(&priv->mutex);
+}
+EXPORT_SYMBOL_GPL(ipu_dc_enable);
+
+void ipu_dc_enable_channel(struct ipu_dc *dc)
+{
+	u32 reg;
+
+	reg = readl(dc->base + DC_WR_CH_CONF);
+	reg |= DC_WR_CH_CONF_PROG_TYPE_NORMAL;
+	writel(reg, dc->base + DC_WR_CH_CONF);
+}
+EXPORT_SYMBOL_GPL(ipu_dc_enable_channel);
+
+void ipu_dc_disable_channel(struct ipu_dc *dc)
+{
+	u32 val;
+
+	val = readl(dc->base + DC_WR_CH_CONF);
+	val &= ~DC_WR_CH_CONF_PROG_TYPE_MASK;
+	writel(val, dc->base + DC_WR_CH_CONF);
+}
+EXPORT_SYMBOL_GPL(ipu_dc_disable_channel);
+
+void ipu_dc_disable(struct ipu_soc *ipu)
+{
+	struct ipu_dc_priv *priv = ipu->dc_priv;
+
+	mutex_lock(&priv->mutex);
+
+	priv->use_count--;
+	if (!priv->use_count)
+		ipu_module_disable(priv->ipu, IPU_CONF_DC_EN);
+
+	if (priv->use_count < 0)
+		priv->use_count = 0;
+
+	mutex_unlock(&priv->mutex);
+}
+EXPORT_SYMBOL_GPL(ipu_dc_disable);
+
+static void ipu_dc_map_config(struct ipu_dc_priv *priv, enum ipu_dc_map map,
+		int byte_num, int offset, int mask)
+{
+	int ptr = map * 3 + byte_num;
+	u32 reg;
+
+	reg = readl(priv->dc_reg + DC_MAP_CONF_VAL(ptr));
+	reg &= ~(0xffff << (16 * (ptr & 0x1)));
+	reg |= ((offset << 8) | mask) << (16 * (ptr & 0x1));
+	writel(reg, priv->dc_reg + DC_MAP_CONF_VAL(ptr));
+
+	reg = readl(priv->dc_reg + DC_MAP_CONF_PTR(map));
+	reg &= ~(0x1f << ((16 * (map & 0x1)) + (5 * byte_num)));
+	reg |= ptr << ((16 * (map & 0x1)) + (5 * byte_num));
+	writel(reg, priv->dc_reg + DC_MAP_CONF_PTR(map));
+}
+
+static void ipu_dc_map_clear(struct ipu_dc_priv *priv, int map)
+{
+	u32 reg = readl(priv->dc_reg + DC_MAP_CONF_PTR(map));
+
+	writel(reg & ~(0xffff << (16 * (map & 0x1))),
+		     priv->dc_reg + DC_MAP_CONF_PTR(map));
+}
+
+struct ipu_dc *ipu_dc_get(struct ipu_soc *ipu, int channel)
+{
+	struct ipu_dc_priv *priv = ipu->dc_priv;
+	struct ipu_dc *dc;
+
+	if (channel >= IPU_DC_NUM_CHANNELS)
+		return ERR_PTR(-ENODEV);
+
+	dc = &priv->channels[channel];
+
+	mutex_lock(&priv->mutex);
+
+	if (dc->in_use) {
+		mutex_unlock(&priv->mutex);
+		return ERR_PTR(-EBUSY);
+	}
+
+	dc->in_use = true;
+
+	mutex_unlock(&priv->mutex);
+
+	return dc;
+}
+EXPORT_SYMBOL_GPL(ipu_dc_get);
+
+void ipu_dc_put(struct ipu_dc *dc)
+{
+	struct ipu_dc_priv *priv = dc->priv;
+
+	mutex_lock(&priv->mutex);
+	dc->in_use = false;
+	mutex_unlock(&priv->mutex);
+}
+EXPORT_SYMBOL_GPL(ipu_dc_put);
+
+int ipu_dc_init(struct ipu_soc *ipu, struct device *dev,
+		unsigned long base, unsigned long template_base)
+{
+	struct ipu_dc_priv *priv;
+	static const int channel_offsets[] = {
+		0, 0x1c, 0x38, 0x54, 0x58, 0x5c, 0x78, 0, 0x94, 0xb4
+	};
+	int i;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	mutex_init(&priv->mutex);
+
+	priv->dev = dev;
+	priv->ipu = ipu;
+	priv->dc_reg = devm_ioremap(dev, base, PAGE_SIZE);
+	priv->dc_tmpl_reg = devm_ioremap(dev, template_base, PAGE_SIZE);
+	if (!priv->dc_reg || !priv->dc_tmpl_reg)
+		return -ENOMEM;
+
+	for (i = 0; i < IPU_DC_NUM_CHANNELS; i++) {
+		priv->channels[i].chno = i;
+		priv->channels[i].priv = priv;
+		priv->channels[i].base = priv->dc_reg + channel_offsets[i];
+	}
+
+	writel(DC_WR_CH_CONF_WORD_SIZE_24 | DC_WR_CH_CONF_DISP_ID_PARALLEL(1) |
+			DC_WR_CH_CONF_PROG_DI_ID,
+			priv->channels[1].base + DC_WR_CH_CONF);
+	writel(DC_WR_CH_CONF_WORD_SIZE_24 | DC_WR_CH_CONF_DISP_ID_PARALLEL(0),
+			priv->channels[5].base + DC_WR_CH_CONF);
+
+	writel(DC_GEN_SYNC_1_6_SYNC | DC_GEN_SYNC_PRIORITY_1,
+		priv->dc_reg + DC_GEN);
+
+	ipu->dc_priv = priv;
+
+	dev_dbg(dev, "DC base: 0x%08lx template base: 0x%08lx\n",
+			base, template_base);
+
+	/* rgb24 */
+	ipu_dc_map_clear(priv, IPU_DC_MAP_RGB24);
+	ipu_dc_map_config(priv, IPU_DC_MAP_RGB24, 0, 7, 0xff); /* blue */
+	ipu_dc_map_config(priv, IPU_DC_MAP_RGB24, 1, 15, 0xff); /* green */
+	ipu_dc_map_config(priv, IPU_DC_MAP_RGB24, 2, 23, 0xff); /* red */
+
+	/* rgb565 */
+	ipu_dc_map_clear(priv, IPU_DC_MAP_RGB565);
+	ipu_dc_map_config(priv, IPU_DC_MAP_RGB565, 0, 4, 0xf8); /* blue */
+	ipu_dc_map_config(priv, IPU_DC_MAP_RGB565, 1, 10, 0xfc); /* green */
+	ipu_dc_map_config(priv, IPU_DC_MAP_RGB565, 2, 15, 0xf8); /* red */
+
+	/* gbr24 */
+	ipu_dc_map_clear(priv, IPU_DC_MAP_GBR24);
+	ipu_dc_map_config(priv, IPU_DC_MAP_GBR24, 2, 15, 0xff); /* green */
+	ipu_dc_map_config(priv, IPU_DC_MAP_GBR24, 1, 7, 0xff); /* blue */
+	ipu_dc_map_config(priv, IPU_DC_MAP_GBR24, 0, 23, 0xff); /* red */
+
+	/* bgr666 */
+	ipu_dc_map_clear(priv, IPU_DC_MAP_BGR666);
+	ipu_dc_map_config(priv, IPU_DC_MAP_BGR666, 0, 5, 0xfc); /* blue */
+	ipu_dc_map_config(priv, IPU_DC_MAP_BGR666, 1, 11, 0xfc); /* green */
+	ipu_dc_map_config(priv, IPU_DC_MAP_BGR666, 2, 17, 0xfc); /* red */
+
+	/* lvds666 */
+	ipu_dc_map_clear(priv, IPU_DC_MAP_LVDS666);
+	ipu_dc_map_config(priv, IPU_DC_MAP_LVDS666, 0, 5, 0xfc); /* blue */
+	ipu_dc_map_config(priv, IPU_DC_MAP_LVDS666, 1, 13, 0xfc); /* green */
+	ipu_dc_map_config(priv, IPU_DC_MAP_LVDS666, 2, 21, 0xfc); /* red */
+
+	/* bgr24 */
+	ipu_dc_map_clear(priv, IPU_DC_MAP_BGR24);
+	ipu_dc_map_config(priv, IPU_DC_MAP_BGR24, 2, 7, 0xff); /* red */
+	ipu_dc_map_config(priv, IPU_DC_MAP_BGR24, 1, 15, 0xff); /* green */
+	ipu_dc_map_config(priv, IPU_DC_MAP_BGR24, 0, 23, 0xff); /* blue */
+
+	return 0;
+}
+
+void ipu_dc_exit(struct ipu_soc *ipu)
+{
+}