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, 354 insertions, 0 deletions

diff --git a/drivers/bcma/driver_mips.c b/drivers/bcma/driver_mips.c
new file mode 100644
index 000000000..9be0806eb
--- /dev/null
+++ b/drivers/bcma/driver_mips.c
@@ -0,0 +1,354 @@
+/*
+ * Broadcom specific AMBA
+ * Broadcom MIPS32 74K core driver
+ *
+ * Copyright 2009, Broadcom Corporation
+ * Copyright 2006, 2007, Michael Buesch <mb@bu3sch.de>
+ * Copyright 2010, Bernhard Loos <bernhardloos@googlemail.com>
+ * Copyright 2011, Hauke Mehrtens <hauke@hauke-m.de>
+ *
+ * Licensed under the GNU/GPL. See COPYING for details.
+ */
+
+#include "bcma_private.h"
+
+#include <linux/bcma/bcma.h>
+
+#include <linux/serial.h>
+#include <linux/serial_core.h>
+#include <linux/serial_reg.h>
+#include <linux/time.h>
+#ifdef CONFIG_BCM47XX
+#include <linux/bcm47xx_nvram.h>
+#endif
+
+enum bcma_boot_dev {
+	BCMA_BOOT_DEV_UNK = 0,
+	BCMA_BOOT_DEV_ROM,
+	BCMA_BOOT_DEV_PARALLEL,
+	BCMA_BOOT_DEV_SERIAL,
+	BCMA_BOOT_DEV_NAND,
+};
+
+/* The 47162a0 hangs when reading MIPS DMP registers */
+static inline bool bcma_core_mips_bcm47162a0_quirk(struct bcma_device *dev)
+{
+	return dev->bus->chipinfo.id == BCMA_CHIP_ID_BCM47162 &&
+	       dev->bus->chipinfo.rev == 0 && dev->id.id == BCMA_CORE_MIPS_74K;
+}
+
+/* The 5357b0 hangs when reading USB20H DMP registers */
+static inline bool bcma_core_mips_bcm5357b0_quirk(struct bcma_device *dev)
+{
+	return (dev->bus->chipinfo.id == BCMA_CHIP_ID_BCM5357 ||
+		dev->bus->chipinfo.id == BCMA_CHIP_ID_BCM4749) &&
+	       dev->bus->chipinfo.pkg == 11 &&
+	       dev->id.id == BCMA_CORE_USB20_HOST;
+}
+
+static u32 bcma_core_mips_irqflag(struct bcma_device *dev)
+{
+	u32 flag;
+
+	if (bcma_core_mips_bcm47162a0_quirk(dev))
+		return dev->core_index;
+	if (bcma_core_mips_bcm5357b0_quirk(dev))
+		return dev->core_index;
+	flag = bcma_aread32(dev, BCMA_MIPS_OOBSELOUTA30);
+
+	if (flag)
+		return flag & 0x1F;
+	else
+		return 0x3f;
+}
+
+/* Get the MIPS IRQ assignment for a specified device.
+ * If unassigned, 0 is returned.
+ * If disabled, 5 is returned.
+ * If not supported, 6 is returned.
+ */
+unsigned int bcma_core_mips_irq(struct bcma_device *dev)
+{
+	struct bcma_device *mdev = dev->bus->drv_mips.core;
+	u32 irqflag;
+	unsigned int irq;
+
+	irqflag = bcma_core_mips_irqflag(dev);
+	if (irqflag == 0x3f)
+		return 6;
+
+	for (irq = 0; irq <= 4; irq++)
+		if (bcma_read32(mdev, BCMA_MIPS_MIPS74K_INTMASK(irq)) &
+		    (1 << irqflag))
+			return irq;
+
+	return 5;
+}
+
+static void bcma_core_mips_set_irq(struct bcma_device *dev, unsigned int irq)
+{
+	unsigned int oldirq = bcma_core_mips_irq(dev);
+	struct bcma_bus *bus = dev->bus;
+	struct bcma_device *mdev = bus->drv_mips.core;
+	u32 irqflag;
+
+	irqflag = bcma_core_mips_irqflag(dev);
+	BUG_ON(oldirq == 6);
+
+	dev->irq = irq + 2;
+
+	/* clear the old irq */
+	if (oldirq == 0)
+		bcma_write32(mdev, BCMA_MIPS_MIPS74K_INTMASK(0),
+			    bcma_read32(mdev, BCMA_MIPS_MIPS74K_INTMASK(0)) &
+			    ~(1 << irqflag));
+	else if (oldirq != 5)
+		bcma_write32(mdev, BCMA_MIPS_MIPS74K_INTMASK(oldirq), 0);
+
+	/* assign the new one */
+	if (irq == 0) {
+		bcma_write32(mdev, BCMA_MIPS_MIPS74K_INTMASK(0),
+			    bcma_read32(mdev, BCMA_MIPS_MIPS74K_INTMASK(0)) |
+			    (1 << irqflag));
+	} else {
+		u32 irqinitmask = bcma_read32(mdev,
+					      BCMA_MIPS_MIPS74K_INTMASK(irq));
+		if (irqinitmask) {
+			struct bcma_device *core;
+
+			/* backplane irq line is in use, find out who uses
+			 * it and set user to irq 0
+			 */
+			list_for_each_entry(core, &bus->cores, list) {
+				if ((1 << bcma_core_mips_irqflag(core)) ==
+				    irqinitmask) {
+					bcma_core_mips_set_irq(core, 0);
+					break;
+				}
+			}
+		}
+		bcma_write32(mdev, BCMA_MIPS_MIPS74K_INTMASK(irq),
+			     1 << irqflag);
+	}
+
+	bcma_debug(bus, "set_irq: core 0x%04x, irq %d => %d\n",
+		   dev->id.id, oldirq <= 4 ? oldirq + 2 : 0, irq + 2);
+}
+
+static void bcma_core_mips_set_irq_name(struct bcma_bus *bus, unsigned int irq,
+					u16 coreid, u8 unit)
+{
+	struct bcma_device *core;
+
+	core = bcma_find_core_unit(bus, coreid, unit);
+	if (!core) {
+		bcma_warn(bus,
+			  "Can not find core (id: 0x%x, unit %i) for IRQ configuration.\n",
+			  coreid, unit);
+		return;
+	}
+
+	bcma_core_mips_set_irq(core, irq);
+}
+
+static void bcma_core_mips_print_irq(struct bcma_device *dev, unsigned int irq)
+{
+	int i;
+	static const char *irq_name[] = {"2(S)", "3", "4", "5", "6", "D", "I"};
+	char interrupts[25];
+	char *ints = interrupts;
+
+	for (i = 0; i < ARRAY_SIZE(irq_name); i++)
+		ints += sprintf(ints, " %s%c",
+				irq_name[i], i == irq ? '*' : ' ');
+
+	bcma_debug(dev->bus, "core 0x%04x, irq:%s\n", dev->id.id, interrupts);
+}
+
+static void bcma_core_mips_dump_irq(struct bcma_bus *bus)
+{
+	struct bcma_device *core;
+
+	list_for_each_entry(core, &bus->cores, list) {
+		bcma_core_mips_print_irq(core, bcma_core_mips_irq(core));
+	}
+}
+
+u32 bcma_cpu_clock(struct bcma_drv_mips *mcore)
+{
+	struct bcma_bus *bus = mcore->core->bus;
+
+	if (bus->drv_cc.capabilities & BCMA_CC_CAP_PMU)
+		return bcma_pmu_get_cpu_clock(&bus->drv_cc);
+
+	bcma_err(bus, "No PMU available, need this to get the cpu clock\n");
+	return 0;
+}
+EXPORT_SYMBOL(bcma_cpu_clock);
+
+static enum bcma_boot_dev bcma_boot_dev(struct bcma_bus *bus)
+{
+	struct bcma_drv_cc *cc = &bus->drv_cc;
+	u8 cc_rev = cc->core->id.rev;
+
+	if (cc_rev == 42) {
+		struct bcma_device *core;
+
+		core = bcma_find_core(bus, BCMA_CORE_NS_ROM);
+		if (core) {
+			switch (bcma_aread32(core, BCMA_IOST) &
+				BCMA_NS_ROM_IOST_BOOT_DEV_MASK) {
+			case BCMA_NS_ROM_IOST_BOOT_DEV_NOR:
+				return BCMA_BOOT_DEV_SERIAL;
+			case BCMA_NS_ROM_IOST_BOOT_DEV_NAND:
+				return BCMA_BOOT_DEV_NAND;
+			case BCMA_NS_ROM_IOST_BOOT_DEV_ROM:
+			default:
+				return BCMA_BOOT_DEV_ROM;
+			}
+		}
+	} else {
+		if (cc_rev == 38) {
+			if (cc->status & BCMA_CC_CHIPST_5357_NAND_BOOT)
+				return BCMA_BOOT_DEV_NAND;
+			else if (cc->status & BIT(5))
+				return BCMA_BOOT_DEV_ROM;
+		}
+
+		if ((cc->capabilities & BCMA_CC_CAP_FLASHT) ==
+		    BCMA_CC_FLASHT_PARA)
+			return BCMA_BOOT_DEV_PARALLEL;
+		else
+			return BCMA_BOOT_DEV_SERIAL;
+	}
+
+	return BCMA_BOOT_DEV_SERIAL;
+}
+
+static void bcma_core_mips_nvram_init(struct bcma_drv_mips *mcore)
+{
+	struct bcma_bus *bus = mcore->core->bus;
+	enum bcma_boot_dev boot_dev;
+
+	/* Determine flash type this SoC boots from */
+	boot_dev = bcma_boot_dev(bus);
+	switch (boot_dev) {
+	case BCMA_BOOT_DEV_PARALLEL:
+	case BCMA_BOOT_DEV_SERIAL:
+#ifdef CONFIG_BCM47XX
+		bcm47xx_nvram_init_from_mem(BCMA_SOC_FLASH2,
+					    BCMA_SOC_FLASH2_SZ);
+#endif
+		break;
+	case BCMA_BOOT_DEV_NAND:
+#ifdef CONFIG_BCM47XX
+		bcm47xx_nvram_init_from_mem(BCMA_SOC_FLASH1,
+					    BCMA_SOC_FLASH1_SZ);
+#endif
+		break;
+	default:
+		break;
+	}
+}
+
+void bcma_core_mips_early_init(struct bcma_drv_mips *mcore)
+{
+	struct bcma_bus *bus = mcore->core->bus;
+
+	if (mcore->early_setup_done)
+		return;
+
+	bcma_chipco_serial_init(&bus->drv_cc);
+	bcma_core_mips_nvram_init(mcore);
+
+	mcore->early_setup_done = true;
+}
+
+static void bcma_fix_i2s_irqflag(struct bcma_bus *bus)
+{
+	struct bcma_device *cpu, *pcie, *i2s;
+
+	/* Fixup the interrupts in 4716/4748 for i2s core (2010 Broadcom SDK)
+	 * (IRQ flags > 7 are ignored when setting the interrupt masks)
+	 */
+	if (bus->chipinfo.id != BCMA_CHIP_ID_BCM4716 &&
+	    bus->chipinfo.id != BCMA_CHIP_ID_BCM4748)
+		return;
+
+	cpu = bcma_find_core(bus, BCMA_CORE_MIPS_74K);
+	pcie = bcma_find_core(bus, BCMA_CORE_PCIE);
+	i2s = bcma_find_core(bus, BCMA_CORE_I2S);
+	if (cpu && pcie && i2s &&
+	    bcma_aread32(cpu, BCMA_MIPS_OOBSELINA74) == 0x08060504 &&
+	    bcma_aread32(pcie, BCMA_MIPS_OOBSELINA74) == 0x08060504 &&
+	    bcma_aread32(i2s, BCMA_MIPS_OOBSELOUTA30) == 0x88) {
+		bcma_awrite32(cpu, BCMA_MIPS_OOBSELINA74, 0x07060504);
+		bcma_awrite32(pcie, BCMA_MIPS_OOBSELINA74, 0x07060504);
+		bcma_awrite32(i2s, BCMA_MIPS_OOBSELOUTA30, 0x87);
+		bcma_debug(bus,
+			   "Moved i2s interrupt to oob line 7 instead of 8\n");
+	}
+}
+
+void bcma_core_mips_init(struct bcma_drv_mips *mcore)
+{
+	struct bcma_bus *bus;
+	struct bcma_device *core;
+	bus = mcore->core->bus;
+
+	if (mcore->setup_done)
+		return;
+
+	bcma_debug(bus, "Initializing MIPS core...\n");
+
+	bcma_core_mips_early_init(mcore);
+
+	bcma_fix_i2s_irqflag(bus);
+
+	switch (bus->chipinfo.id) {
+	case BCMA_CHIP_ID_BCM4716:
+	case BCMA_CHIP_ID_BCM4748:
+		bcma_core_mips_set_irq_name(bus, 1, BCMA_CORE_80211, 0);
+		bcma_core_mips_set_irq_name(bus, 2, BCMA_CORE_MAC_GBIT, 0);
+		bcma_core_mips_set_irq_name(bus, 3, BCMA_CORE_USB20_HOST, 0);
+		bcma_core_mips_set_irq_name(bus, 4, BCMA_CORE_PCIE, 0);
+		bcma_core_mips_set_irq_name(bus, 0, BCMA_CORE_CHIPCOMMON, 0);
+		bcma_core_mips_set_irq_name(bus, 0, BCMA_CORE_I2S, 0);
+		break;
+	case BCMA_CHIP_ID_BCM5356:
+	case BCMA_CHIP_ID_BCM47162:
+	case BCMA_CHIP_ID_BCM53572:
+		bcma_core_mips_set_irq_name(bus, 1, BCMA_CORE_80211, 0);
+		bcma_core_mips_set_irq_name(bus, 2, BCMA_CORE_MAC_GBIT, 0);
+		bcma_core_mips_set_irq_name(bus, 0, BCMA_CORE_CHIPCOMMON, 0);
+		break;
+	case BCMA_CHIP_ID_BCM5357:
+	case BCMA_CHIP_ID_BCM4749:
+		bcma_core_mips_set_irq_name(bus, 1, BCMA_CORE_80211, 0);
+		bcma_core_mips_set_irq_name(bus, 2, BCMA_CORE_MAC_GBIT, 0);
+		bcma_core_mips_set_irq_name(bus, 3, BCMA_CORE_USB20_HOST, 0);
+		bcma_core_mips_set_irq_name(bus, 0, BCMA_CORE_CHIPCOMMON, 0);
+		bcma_core_mips_set_irq_name(bus, 0, BCMA_CORE_I2S, 0);
+		break;
+	case BCMA_CHIP_ID_BCM4706:
+		bcma_core_mips_set_irq_name(bus, 1, BCMA_CORE_PCIE, 0);
+		bcma_core_mips_set_irq_name(bus, 2, BCMA_CORE_4706_MAC_GBIT,
+					    0);
+		bcma_core_mips_set_irq_name(bus, 3, BCMA_CORE_PCIE, 1);
+		bcma_core_mips_set_irq_name(bus, 4, BCMA_CORE_USB20_HOST, 0);
+		bcma_core_mips_set_irq_name(bus, 0, BCMA_CORE_4706_CHIPCOMMON,
+					    0);
+		break;
+	default:
+		list_for_each_entry(core, &bus->cores, list) {
+			core->irq = bcma_core_irq(core, 0);
+		}
+		bcma_err(bus,
+			 "Unknown device (0x%x) found, can not configure IRQs\n",
+			 bus->chipinfo.id);
+	}
+	bcma_debug(bus, "IRQ reconfiguration done\n");
+	bcma_core_mips_dump_irq(bus);
+
+	mcore->setup_done = true;
+}