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, 263 insertions, 0 deletions

diff --git a/drivers/misc/cardreader/rts5229.c b/drivers/misc/cardreader/rts5229.c
new file mode 100644
index 000000000..b0edd8006
--- /dev/null
+++ b/drivers/misc/cardreader/rts5229.c
@@ -0,0 +1,263 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Driver for Realtek PCI-Express card reader
+ *
+ * Copyright(c) 2009-2013 Realtek Semiconductor Corp. All rights reserved.
+ *
+ * Author:
+ *   Wei WANG <wei_wang@realsil.com.cn>
+ */
+
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/rtsx_pci.h>
+
+#include "rtsx_pcr.h"
+
+static u8 rts5229_get_ic_version(struct rtsx_pcr *pcr)
+{
+	u8 val;
+
+	rtsx_pci_read_register(pcr, DUMMY_REG_RESET_0, &val);
+	return val & 0x0F;
+}
+
+static void rts5229_fetch_vendor_settings(struct rtsx_pcr *pcr)
+{
+	struct pci_dev *pdev = pcr->pci;
+	u32 reg;
+
+	pci_read_config_dword(pdev, PCR_SETTING_REG1, &reg);
+	pcr_dbg(pcr, "Cfg 0x%x: 0x%x\n", PCR_SETTING_REG1, reg);
+
+	if (!rtsx_vendor_setting_valid(reg))
+		return;
+
+	pcr->aspm_en = rtsx_reg_to_aspm(reg);
+	pcr->sd30_drive_sel_1v8 =
+		map_sd_drive(rtsx_reg_to_sd30_drive_sel_1v8(reg));
+	pcr->card_drive_sel &= 0x3F;
+	pcr->card_drive_sel |= rtsx_reg_to_card_drive_sel(reg);
+
+	pci_read_config_dword(pdev, PCR_SETTING_REG2, &reg);
+	pcr_dbg(pcr, "Cfg 0x%x: 0x%x\n", PCR_SETTING_REG2, reg);
+	pcr->sd30_drive_sel_3v3 =
+		map_sd_drive(rtsx_reg_to_sd30_drive_sel_3v3(reg));
+}
+
+static void rts5229_force_power_down(struct rtsx_pcr *pcr, u8 pm_state, bool runtime)
+{
+	rtsx_pci_write_register(pcr, FPDCTL, 0x03, 0x03);
+}
+
+static int rts5229_extra_init_hw(struct rtsx_pcr *pcr)
+{
+	rtsx_pci_init_cmd(pcr);
+
+	/* Configure GPIO as output */
+	rtsx_pci_add_cmd(pcr, WRITE_REG_CMD, GPIO_CTL, 0x02, 0x02);
+	/* Reset ASPM state to default value */
+	rtsx_pci_add_cmd(pcr, WRITE_REG_CMD, ASPM_FORCE_CTL, 0x3F, 0);
+	/* Force CLKREQ# PIN to drive 0 to request clock */
+	rtsx_pci_add_cmd(pcr, WRITE_REG_CMD, PETXCFG, 0x08, 0x08);
+	/* Switch LDO3318 source from DV33 to card_3v3 */
+	rtsx_pci_add_cmd(pcr, WRITE_REG_CMD, LDO_PWR_SEL, 0x03, 0x00);
+	rtsx_pci_add_cmd(pcr, WRITE_REG_CMD, LDO_PWR_SEL, 0x03, 0x01);
+	/* LED shine disabled, set initial shine cycle period */
+	rtsx_pci_add_cmd(pcr, WRITE_REG_CMD, OLT_LED_CTL, 0x0F, 0x02);
+	/* Configure driving */
+	rtsx_pci_add_cmd(pcr, WRITE_REG_CMD, SD30_DRIVE_SEL,
+			0xFF, pcr->sd30_drive_sel_3v3);
+
+	return rtsx_pci_send_cmd(pcr, 100);
+}
+
+static int rts5229_optimize_phy(struct rtsx_pcr *pcr)
+{
+	/* Optimize RX sensitivity */
+	return rtsx_pci_write_phy_register(pcr, 0x00, 0xBA42);
+}
+
+static int rts5229_turn_on_led(struct rtsx_pcr *pcr)
+{
+	return rtsx_pci_write_register(pcr, GPIO_CTL, 0x02, 0x02);
+}
+
+static int rts5229_turn_off_led(struct rtsx_pcr *pcr)
+{
+	return rtsx_pci_write_register(pcr, GPIO_CTL, 0x02, 0x00);
+}
+
+static int rts5229_enable_auto_blink(struct rtsx_pcr *pcr)
+{
+	return rtsx_pci_write_register(pcr, OLT_LED_CTL, 0x08, 0x08);
+}
+
+static int rts5229_disable_auto_blink(struct rtsx_pcr *pcr)
+{
+	return rtsx_pci_write_register(pcr, OLT_LED_CTL, 0x08, 0x00);
+}
+
+static int rts5229_card_power_on(struct rtsx_pcr *pcr, int card)
+{
+	int err;
+
+	rtsx_pci_init_cmd(pcr);
+	rtsx_pci_add_cmd(pcr, WRITE_REG_CMD, CARD_PWR_CTL,
+			SD_POWER_MASK, SD_PARTIAL_POWER_ON);
+	rtsx_pci_add_cmd(pcr, WRITE_REG_CMD, PWR_GATE_CTRL,
+			LDO3318_PWR_MASK, 0x02);
+	err = rtsx_pci_send_cmd(pcr, 100);
+	if (err < 0)
+		return err;
+
+	/* To avoid too large in-rush current */
+	udelay(150);
+
+	rtsx_pci_init_cmd(pcr);
+	rtsx_pci_add_cmd(pcr, WRITE_REG_CMD, CARD_PWR_CTL,
+			SD_POWER_MASK, SD_POWER_ON);
+	rtsx_pci_add_cmd(pcr, WRITE_REG_CMD, PWR_GATE_CTRL,
+			LDO3318_PWR_MASK, 0x06);
+	return rtsx_pci_send_cmd(pcr, 100);
+}
+
+static int rts5229_card_power_off(struct rtsx_pcr *pcr, int card)
+{
+	rtsx_pci_init_cmd(pcr);
+	rtsx_pci_add_cmd(pcr, WRITE_REG_CMD, CARD_PWR_CTL,
+			SD_POWER_MASK | PMOS_STRG_MASK,
+			SD_POWER_OFF | PMOS_STRG_400mA);
+	rtsx_pci_add_cmd(pcr, WRITE_REG_CMD, PWR_GATE_CTRL,
+			LDO3318_PWR_MASK, 0x00);
+	return rtsx_pci_send_cmd(pcr, 100);
+}
+
+static int rts5229_switch_output_voltage(struct rtsx_pcr *pcr, u8 voltage)
+{
+	int err;
+
+	if (voltage == OUTPUT_3V3) {
+		err = rtsx_pci_write_register(pcr,
+				SD30_DRIVE_SEL, 0x07, pcr->sd30_drive_sel_3v3);
+		if (err < 0)
+			return err;
+		err = rtsx_pci_write_phy_register(pcr, 0x08, 0x4FC0 | 0x24);
+		if (err < 0)
+			return err;
+	} else if (voltage == OUTPUT_1V8) {
+		err = rtsx_pci_write_register(pcr,
+				SD30_DRIVE_SEL, 0x07, pcr->sd30_drive_sel_1v8);
+		if (err < 0)
+			return err;
+		err = rtsx_pci_write_phy_register(pcr, 0x08, 0x4C40 | 0x24);
+		if (err < 0)
+			return err;
+	} else {
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static const struct pcr_ops rts5229_pcr_ops = {
+	.fetch_vendor_settings = rts5229_fetch_vendor_settings,
+	.extra_init_hw = rts5229_extra_init_hw,
+	.optimize_phy = rts5229_optimize_phy,
+	.turn_on_led = rts5229_turn_on_led,
+	.turn_off_led = rts5229_turn_off_led,
+	.enable_auto_blink = rts5229_enable_auto_blink,
+	.disable_auto_blink = rts5229_disable_auto_blink,
+	.card_power_on = rts5229_card_power_on,
+	.card_power_off = rts5229_card_power_off,
+	.switch_output_voltage = rts5229_switch_output_voltage,
+	.cd_deglitch = NULL,
+	.conv_clk_and_div_n = NULL,
+	.force_power_down = rts5229_force_power_down,
+};
+
+/* SD Pull Control Enable:
+ *     SD_DAT[3:0] ==> pull up
+ *     SD_CD       ==> pull up
+ *     SD_WP       ==> pull up
+ *     SD_CMD      ==> pull up
+ *     SD_CLK      ==> pull down
+ */
+static const u32 rts5229_sd_pull_ctl_enable_tbl1[] = {
+	RTSX_REG_PAIR(CARD_PULL_CTL2, 0xAA),
+	RTSX_REG_PAIR(CARD_PULL_CTL3, 0xE9),
+	0,
+};
+
+/* For RTS5229 version C */
+static const u32 rts5229_sd_pull_ctl_enable_tbl2[] = {
+	RTSX_REG_PAIR(CARD_PULL_CTL2, 0xAA),
+	RTSX_REG_PAIR(CARD_PULL_CTL3, 0xD9),
+	0,
+};
+
+/* SD Pull Control Disable:
+ *     SD_DAT[3:0] ==> pull down
+ *     SD_CD       ==> pull up
+ *     SD_WP       ==> pull down
+ *     SD_CMD      ==> pull down
+ *     SD_CLK      ==> pull down
+ */
+static const u32 rts5229_sd_pull_ctl_disable_tbl1[] = {
+	RTSX_REG_PAIR(CARD_PULL_CTL2, 0x55),
+	RTSX_REG_PAIR(CARD_PULL_CTL3, 0xD5),
+	0,
+};
+
+/* For RTS5229 version C */
+static const u32 rts5229_sd_pull_ctl_disable_tbl2[] = {
+	RTSX_REG_PAIR(CARD_PULL_CTL2, 0x55),
+	RTSX_REG_PAIR(CARD_PULL_CTL3, 0xE5),
+	0,
+};
+
+/* MS Pull Control Enable:
+ *     MS CD       ==> pull up
+ *     others      ==> pull down
+ */
+static const u32 rts5229_ms_pull_ctl_enable_tbl[] = {
+	RTSX_REG_PAIR(CARD_PULL_CTL5, 0x55),
+	RTSX_REG_PAIR(CARD_PULL_CTL6, 0x15),
+	0,
+};
+
+/* MS Pull Control Disable:
+ *     MS CD       ==> pull up
+ *     others      ==> pull down
+ */
+static const u32 rts5229_ms_pull_ctl_disable_tbl[] = {
+	RTSX_REG_PAIR(CARD_PULL_CTL5, 0x55),
+	RTSX_REG_PAIR(CARD_PULL_CTL6, 0x15),
+	0,
+};
+
+void rts5229_init_params(struct rtsx_pcr *pcr)
+{
+	pcr->extra_caps = EXTRA_CAPS_SD_SDR50 | EXTRA_CAPS_SD_SDR104;
+	pcr->num_slots = 2;
+	pcr->ops = &rts5229_pcr_ops;
+
+	pcr->flags = 0;
+	pcr->card_drive_sel = RTSX_CARD_DRIVE_DEFAULT;
+	pcr->sd30_drive_sel_1v8 = DRIVER_TYPE_B;
+	pcr->sd30_drive_sel_3v3 = DRIVER_TYPE_D;
+	pcr->aspm_en = ASPM_L1_EN;
+	pcr->aspm_mode = ASPM_MODE_CFG;
+	pcr->tx_initial_phase = SET_CLOCK_PHASE(27, 27, 15);
+	pcr->rx_initial_phase = SET_CLOCK_PHASE(30, 6, 6);
+
+	pcr->ic_version = rts5229_get_ic_version(pcr);
+	if (pcr->ic_version == IC_VER_C) {
+		pcr->sd_pull_ctl_enable_tbl = rts5229_sd_pull_ctl_enable_tbl2;
+		pcr->sd_pull_ctl_disable_tbl = rts5229_sd_pull_ctl_disable_tbl2;
+	} else {
+		pcr->sd_pull_ctl_enable_tbl = rts5229_sd_pull_ctl_enable_tbl1;
+		pcr->sd_pull_ctl_disable_tbl = rts5229_sd_pull_ctl_disable_tbl1;
+	}
+	pcr->ms_pull_ctl_enable_tbl = rts5229_ms_pull_ctl_enable_tbl;
+	pcr->ms_pull_ctl_disable_tbl = rts5229_ms_pull_ctl_disable_tbl;
+}