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

4 files changed, 937 insertions, 0 deletions

diff --git a/drivers/peci/controller/Kconfig b/drivers/peci/controller/Kconfig
new file mode 100644
index 000000000..4f9c245ad
--- /dev/null
+++ b/drivers/peci/controller/Kconfig
@@ -0,0 +1,34 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+config PECI_ASPEED
+	tristate "ASPEED PECI support"
+	depends on ARCH_ASPEED || COMPILE_TEST
+	depends on OF
+	depends on HAS_IOMEM
+	depends on COMMON_CLK
+	help
+	  This option enables PECI controller driver for ASPEED AST2400,
+	  AST2500 and AST2600 SoCs. It allows BMC to discover devices
+	  connected to it, and communicate with them using PECI protocol.
+
+	  Say Y here if your system runs on ASPEED SoC and you are using it
+	  as BMC for Intel platform.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called peci-aspeed.
+
+config PECI_NPCM
+	tristate "Nuvoton NPCM PECI support"
+	depends on ARCH_NPCM || COMPILE_TEST
+	depends on OF
+	select REGMAP_MMIO
+	help
+	  This option enables PECI controller driver for Nuvoton NPCM7XX
+	  and NPCM8XX SoCs. It allows BMC to discover devices connected
+	  to it and communicate with them using PECI protocol.
+
+	  Say Y here if you want support for the Platform Environment Control
+	  Interface (PECI) bus adapter driver on the Nuvoton NPCM SoCs.
+
+	  This support is also available as a module. If so, the module
+	  will be called peci-npcm.
diff --git a/drivers/peci/controller/Makefile b/drivers/peci/controller/Makefile
new file mode 100644
index 000000000..e247449bb
--- /dev/null
+++ b/drivers/peci/controller/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+obj-$(CONFIG_PECI_ASPEED)	+= peci-aspeed.o
+obj-$(CONFIG_PECI_NPCM)		+= peci-npcm.o
diff --git a/drivers/peci/controller/peci-aspeed.c b/drivers/peci/controller/peci-aspeed.c
new file mode 100644
index 000000000..a0c99ecf7
--- /dev/null
+++ b/drivers/peci/controller/peci-aspeed.c
@@ -0,0 +1,602 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright (c) 2012-2017 ASPEED Technology Inc.
+// Copyright (c) 2018-2021 Intel Corporation
+
+#include <linux/unaligned.h>
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/clkdev.h>
+#include <linux/clk-provider.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/jiffies.h>
+#include <linux/math.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/peci.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+
+/* ASPEED PECI Registers */
+/* Control Register */
+#define ASPEED_PECI_CTRL			0x00
+#define   ASPEED_PECI_CTRL_SAMPLING_MASK	GENMASK(19, 16)
+#define   ASPEED_PECI_CTRL_RD_MODE_MASK		GENMASK(13, 12)
+#define     ASPEED_PECI_CTRL_RD_MODE_DBG	BIT(13)
+#define     ASPEED_PECI_CTRL_RD_MODE_COUNT	BIT(12)
+#define   ASPEED_PECI_CTRL_CLK_SRC_HCLK		BIT(11)
+#define   ASPEED_PECI_CTRL_CLK_DIV_MASK		GENMASK(10, 8)
+#define   ASPEED_PECI_CTRL_INVERT_OUT		BIT(7)
+#define   ASPEED_PECI_CTRL_INVERT_IN		BIT(6)
+#define   ASPEED_PECI_CTRL_BUS_CONTENTION_EN	BIT(5)
+#define   ASPEED_PECI_CTRL_PECI_EN		BIT(4)
+#define   ASPEED_PECI_CTRL_PECI_CLK_EN		BIT(0)
+
+/* Timing Negotiation Register */
+#define ASPEED_PECI_TIMING_NEGOTIATION		0x04
+#define   ASPEED_PECI_T_NEGO_MSG_MASK		GENMASK(15, 8)
+#define   ASPEED_PECI_T_NEGO_ADDR_MASK		GENMASK(7, 0)
+
+/* Command Register */
+#define ASPEED_PECI_CMD				0x08
+#define   ASPEED_PECI_CMD_PIN_MONITORING	BIT(31)
+#define   ASPEED_PECI_CMD_STS_MASK		GENMASK(27, 24)
+#define     ASPEED_PECI_CMD_STS_ADDR_T_NEGO	0x3
+#define   ASPEED_PECI_CMD_IDLE_MASK		\
+	  (ASPEED_PECI_CMD_STS_MASK | ASPEED_PECI_CMD_PIN_MONITORING)
+#define   ASPEED_PECI_CMD_FIRE			BIT(0)
+
+/* Read/Write Length Register */
+#define ASPEED_PECI_RW_LENGTH			0x0c
+#define   ASPEED_PECI_AW_FCS_EN			BIT(31)
+#define   ASPEED_PECI_RD_LEN_MASK		GENMASK(23, 16)
+#define   ASPEED_PECI_WR_LEN_MASK		GENMASK(15, 8)
+#define   ASPEED_PECI_TARGET_ADDR_MASK		GENMASK(7, 0)
+
+/* Expected FCS Data Register */
+#define ASPEED_PECI_EXPECTED_FCS		0x10
+#define   ASPEED_PECI_EXPECTED_RD_FCS_MASK	GENMASK(23, 16)
+#define   ASPEED_PECI_EXPECTED_AW_FCS_AUTO_MASK	GENMASK(15, 8)
+#define   ASPEED_PECI_EXPECTED_WR_FCS_MASK	GENMASK(7, 0)
+
+/* Captured FCS Data Register */
+#define ASPEED_PECI_CAPTURED_FCS		0x14
+#define   ASPEED_PECI_CAPTURED_RD_FCS_MASK	GENMASK(23, 16)
+#define   ASPEED_PECI_CAPTURED_WR_FCS_MASK	GENMASK(7, 0)
+
+/* Interrupt Register */
+#define ASPEED_PECI_INT_CTRL			0x18
+#define   ASPEED_PECI_TIMING_NEGO_SEL_MASK	GENMASK(31, 30)
+#define     ASPEED_PECI_1ST_BIT_OF_ADDR_NEGO	0
+#define     ASPEED_PECI_2ND_BIT_OF_ADDR_NEGO	1
+#define     ASPEED_PECI_MESSAGE_NEGO		2
+#define   ASPEED_PECI_INT_MASK			GENMASK(4, 0)
+#define     ASPEED_PECI_INT_BUS_TIMEOUT		BIT(4)
+#define     ASPEED_PECI_INT_BUS_CONTENTION	BIT(3)
+#define     ASPEED_PECI_INT_WR_FCS_BAD		BIT(2)
+#define     ASPEED_PECI_INT_WR_FCS_ABORT	BIT(1)
+#define     ASPEED_PECI_INT_CMD_DONE		BIT(0)
+
+/* Interrupt Status Register */
+#define ASPEED_PECI_INT_STS			0x1c
+#define   ASPEED_PECI_INT_TIMING_RESULT_MASK	GENMASK(29, 16)
+	  /* bits[4..0]: Same bit fields in the 'Interrupt Register' */
+
+/* Rx/Tx Data Buffer Registers */
+#define ASPEED_PECI_WR_DATA0			0x20
+#define ASPEED_PECI_WR_DATA1			0x24
+#define ASPEED_PECI_WR_DATA2			0x28
+#define ASPEED_PECI_WR_DATA3			0x2c
+#define ASPEED_PECI_RD_DATA0			0x30
+#define ASPEED_PECI_RD_DATA1			0x34
+#define ASPEED_PECI_RD_DATA2			0x38
+#define ASPEED_PECI_RD_DATA3			0x3c
+#define ASPEED_PECI_WR_DATA4			0x40
+#define ASPEED_PECI_WR_DATA5			0x44
+#define ASPEED_PECI_WR_DATA6			0x48
+#define ASPEED_PECI_WR_DATA7			0x4c
+#define ASPEED_PECI_RD_DATA4			0x50
+#define ASPEED_PECI_RD_DATA5			0x54
+#define ASPEED_PECI_RD_DATA6			0x58
+#define ASPEED_PECI_RD_DATA7			0x5c
+#define   ASPEED_PECI_DATA_BUF_SIZE_MAX		32
+
+/* Timing Negotiation */
+#define ASPEED_PECI_CLK_FREQUENCY_MIN		2000
+#define ASPEED_PECI_CLK_FREQUENCY_DEFAULT	1000000
+#define ASPEED_PECI_CLK_FREQUENCY_MAX		2000000
+#define ASPEED_PECI_RD_SAMPLING_POINT_DEFAULT	8
+/* Timeout */
+#define ASPEED_PECI_IDLE_CHECK_TIMEOUT_US	(50 * USEC_PER_MSEC)
+#define ASPEED_PECI_IDLE_CHECK_INTERVAL_US	(10 * USEC_PER_MSEC)
+#define ASPEED_PECI_CMD_TIMEOUT_MS_DEFAULT	1000
+#define ASPEED_PECI_CMD_TIMEOUT_MS_MAX		1000
+
+#define ASPEED_PECI_CLK_DIV1(msg_timing) (4 * (msg_timing) + 1)
+#define ASPEED_PECI_CLK_DIV2(clk_div_exp) BIT(clk_div_exp)
+#define ASPEED_PECI_CLK_DIV(msg_timing, clk_div_exp) \
+	(4 * ASPEED_PECI_CLK_DIV1(msg_timing) * ASPEED_PECI_CLK_DIV2(clk_div_exp))
+
+struct aspeed_peci {
+	struct peci_controller *controller;
+	struct device *dev;
+	void __iomem *base;
+	struct reset_control *rst;
+	int irq;
+	spinlock_t lock; /* to sync completion status handling */
+	struct completion xfer_complete;
+	struct clk *clk;
+	u32 clk_frequency;
+	u32 status;
+	u32 cmd_timeout_ms;
+};
+
+struct clk_aspeed_peci {
+	struct clk_hw hw;
+	struct aspeed_peci *aspeed_peci;
+};
+
+static void aspeed_peci_controller_enable(struct aspeed_peci *priv)
+{
+	u32 val = readl(priv->base + ASPEED_PECI_CTRL);
+
+	val |= ASPEED_PECI_CTRL_PECI_CLK_EN;
+	val |= ASPEED_PECI_CTRL_PECI_EN;
+
+	writel(val, priv->base + ASPEED_PECI_CTRL);
+}
+
+static void aspeed_peci_init_regs(struct aspeed_peci *priv)
+{
+	u32 val;
+
+	/* Clear interrupts */
+	writel(ASPEED_PECI_INT_MASK, priv->base + ASPEED_PECI_INT_STS);
+
+	/* Set timing negotiation mode and enable interrupts */
+	val = FIELD_PREP(ASPEED_PECI_TIMING_NEGO_SEL_MASK, ASPEED_PECI_1ST_BIT_OF_ADDR_NEGO);
+	val |= ASPEED_PECI_INT_MASK;
+	writel(val, priv->base + ASPEED_PECI_INT_CTRL);
+
+	val = FIELD_PREP(ASPEED_PECI_CTRL_SAMPLING_MASK, ASPEED_PECI_RD_SAMPLING_POINT_DEFAULT);
+	writel(val, priv->base + ASPEED_PECI_CTRL);
+}
+
+static int aspeed_peci_check_idle(struct aspeed_peci *priv)
+{
+	u32 cmd_sts = readl(priv->base + ASPEED_PECI_CMD);
+	int ret;
+
+	/*
+	 * Under normal circumstances, we expect to be idle here.
+	 * In case there were any errors/timeouts that led to the situation
+	 * where the hardware is not in idle state - we need to reset and
+	 * reinitialize it to avoid potential controller hang.
+	 */
+	if (FIELD_GET(ASPEED_PECI_CMD_STS_MASK, cmd_sts)) {
+		ret = reset_control_assert(priv->rst);
+		if (ret) {
+			dev_err(priv->dev, "cannot assert reset control\n");
+			return ret;
+		}
+
+		ret = reset_control_deassert(priv->rst);
+		if (ret) {
+			dev_err(priv->dev, "cannot deassert reset control\n");
+			return ret;
+		}
+
+		aspeed_peci_init_regs(priv);
+
+		ret = clk_set_rate(priv->clk, priv->clk_frequency);
+		if (ret < 0) {
+			dev_err(priv->dev, "cannot set clock frequency\n");
+			return ret;
+		}
+
+		aspeed_peci_controller_enable(priv);
+	}
+
+	return readl_poll_timeout(priv->base + ASPEED_PECI_CMD,
+				  cmd_sts,
+				  !(cmd_sts & ASPEED_PECI_CMD_IDLE_MASK),
+				  ASPEED_PECI_IDLE_CHECK_INTERVAL_US,
+				  ASPEED_PECI_IDLE_CHECK_TIMEOUT_US);
+}
+
+static int aspeed_peci_xfer(struct peci_controller *controller,
+			    u8 addr, struct peci_request *req)
+{
+	struct aspeed_peci *priv = dev_get_drvdata(controller->dev.parent);
+	unsigned long timeout = msecs_to_jiffies(priv->cmd_timeout_ms);
+	u32 peci_head;
+	int ret, i;
+
+	if (req->tx.len > ASPEED_PECI_DATA_BUF_SIZE_MAX ||
+	    req->rx.len > ASPEED_PECI_DATA_BUF_SIZE_MAX)
+		return -EINVAL;
+
+	/* Check command sts and bus idle state */
+	ret = aspeed_peci_check_idle(priv);
+	if (ret)
+		return ret; /* -ETIMEDOUT */
+
+	spin_lock_irq(&priv->lock);
+	reinit_completion(&priv->xfer_complete);
+
+	peci_head = FIELD_PREP(ASPEED_PECI_TARGET_ADDR_MASK, addr) |
+		    FIELD_PREP(ASPEED_PECI_WR_LEN_MASK, req->tx.len) |
+		    FIELD_PREP(ASPEED_PECI_RD_LEN_MASK, req->rx.len);
+
+	writel(peci_head, priv->base + ASPEED_PECI_RW_LENGTH);
+
+	for (i = 0; i < req->tx.len; i += 4) {
+		u32 reg = (i < 16 ? ASPEED_PECI_WR_DATA0 : ASPEED_PECI_WR_DATA4) + i % 16;
+
+		writel(get_unaligned_le32(&req->tx.buf[i]), priv->base + reg);
+	}
+
+#if IS_ENABLED(CONFIG_DYNAMIC_DEBUG)
+	dev_dbg(priv->dev, "HEAD : %#08x\n", peci_head);
+	print_hex_dump_bytes("TX : ", DUMP_PREFIX_NONE, req->tx.buf, req->tx.len);
+#endif
+
+	priv->status = 0;
+	writel(ASPEED_PECI_CMD_FIRE, priv->base + ASPEED_PECI_CMD);
+	spin_unlock_irq(&priv->lock);
+
+	ret = wait_for_completion_interruptible_timeout(&priv->xfer_complete, timeout);
+	if (ret < 0)
+		return ret;
+
+	if (ret == 0) {
+		dev_dbg(priv->dev, "timeout waiting for a response\n");
+		return -ETIMEDOUT;
+	}
+
+	spin_lock_irq(&priv->lock);
+
+	if (priv->status != ASPEED_PECI_INT_CMD_DONE) {
+		spin_unlock_irq(&priv->lock);
+		dev_dbg(priv->dev, "no valid response, status: %#02x\n", priv->status);
+		return -EIO;
+	}
+
+	spin_unlock_irq(&priv->lock);
+
+	/*
+	 * We need to use dword reads for register access, make sure that the
+	 * buffer size is multiple of 4-bytes.
+	 */
+	BUILD_BUG_ON(PECI_REQUEST_MAX_BUF_SIZE % 4);
+
+	for (i = 0; i < req->rx.len; i += 4) {
+		u32 reg = (i < 16 ? ASPEED_PECI_RD_DATA0 : ASPEED_PECI_RD_DATA4) + i % 16;
+		u32 rx_data = readl(priv->base + reg);
+
+		put_unaligned_le32(rx_data, &req->rx.buf[i]);
+	}
+
+#if IS_ENABLED(CONFIG_DYNAMIC_DEBUG)
+	print_hex_dump_bytes("RX : ", DUMP_PREFIX_NONE, req->rx.buf, req->rx.len);
+#endif
+	return 0;
+}
+
+static irqreturn_t aspeed_peci_irq_handler(int irq, void *arg)
+{
+	struct aspeed_peci *priv = arg;
+	u32 status;
+
+	spin_lock(&priv->lock);
+	status = readl(priv->base + ASPEED_PECI_INT_STS);
+	writel(status, priv->base + ASPEED_PECI_INT_STS);
+	priv->status |= (status & ASPEED_PECI_INT_MASK);
+
+	/*
+	 * All commands should be ended up with a ASPEED_PECI_INT_CMD_DONE bit
+	 * set even in an error case.
+	 */
+	if (status & ASPEED_PECI_INT_CMD_DONE)
+		complete(&priv->xfer_complete);
+
+	writel(0, priv->base + ASPEED_PECI_CMD);
+
+	spin_unlock(&priv->lock);
+
+	return IRQ_HANDLED;
+}
+
+static void clk_aspeed_peci_find_div_values(unsigned long rate, int *msg_timing, int *clk_div_exp)
+{
+	unsigned long best_diff = ~0ul, diff;
+	int msg_timing_temp, clk_div_exp_temp, i, j;
+
+	for (i = 1; i <= 255; i++)
+		for (j = 0; j < 8; j++) {
+			diff = abs(rate - ASPEED_PECI_CLK_DIV1(i) * ASPEED_PECI_CLK_DIV2(j));
+			if (diff < best_diff) {
+				msg_timing_temp = i;
+				clk_div_exp_temp = j;
+				best_diff = diff;
+			}
+		}
+
+	*msg_timing = msg_timing_temp;
+	*clk_div_exp = clk_div_exp_temp;
+}
+
+static int clk_aspeed_peci_get_div(unsigned long rate, const unsigned long *prate)
+{
+	unsigned long this_rate = *prate / (4 * rate);
+	int msg_timing, clk_div_exp;
+
+	clk_aspeed_peci_find_div_values(this_rate, &msg_timing, &clk_div_exp);
+
+	return ASPEED_PECI_CLK_DIV(msg_timing, clk_div_exp);
+}
+
+static int clk_aspeed_peci_set_rate(struct clk_hw *hw, unsigned long rate,
+				    unsigned long prate)
+{
+	struct clk_aspeed_peci *peci_clk = container_of(hw, struct clk_aspeed_peci, hw);
+	struct aspeed_peci *aspeed_peci = peci_clk->aspeed_peci;
+	unsigned long this_rate = prate / (4 * rate);
+	int clk_div_exp, msg_timing;
+	u32 val;
+
+	clk_aspeed_peci_find_div_values(this_rate, &msg_timing, &clk_div_exp);
+
+	val = readl(aspeed_peci->base + ASPEED_PECI_CTRL);
+	val &= ~ASPEED_PECI_CTRL_CLK_DIV_MASK;
+	val |= FIELD_PREP(ASPEED_PECI_CTRL_CLK_DIV_MASK, clk_div_exp);
+	writel(val, aspeed_peci->base + ASPEED_PECI_CTRL);
+
+	val = FIELD_PREP(ASPEED_PECI_T_NEGO_MSG_MASK, msg_timing);
+	val |= FIELD_PREP(ASPEED_PECI_T_NEGO_ADDR_MASK, msg_timing);
+	writel(val, aspeed_peci->base + ASPEED_PECI_TIMING_NEGOTIATION);
+
+	return 0;
+}
+
+static int clk_aspeed_peci_determine_rate(struct clk_hw *hw,
+					  struct clk_rate_request *req)
+{
+	int div = clk_aspeed_peci_get_div(req->rate, &req->best_parent_rate);
+
+	req->rate = DIV_ROUND_UP_ULL(req->best_parent_rate, div);
+
+	return 0;
+}
+
+static unsigned long clk_aspeed_peci_recalc_rate(struct clk_hw *hw, unsigned long prate)
+{
+	struct clk_aspeed_peci *peci_clk = container_of(hw, struct clk_aspeed_peci, hw);
+	struct aspeed_peci *aspeed_peci = peci_clk->aspeed_peci;
+	int div, msg_timing, addr_timing, clk_div_exp;
+	u32 reg;
+
+	reg = readl(aspeed_peci->base + ASPEED_PECI_TIMING_NEGOTIATION);
+	msg_timing = FIELD_GET(ASPEED_PECI_T_NEGO_MSG_MASK, reg);
+	addr_timing = FIELD_GET(ASPEED_PECI_T_NEGO_ADDR_MASK, reg);
+
+	if (msg_timing != addr_timing)
+		return 0;
+
+	reg = readl(aspeed_peci->base + ASPEED_PECI_CTRL);
+	clk_div_exp = FIELD_GET(ASPEED_PECI_CTRL_CLK_DIV_MASK, reg);
+
+	div = ASPEED_PECI_CLK_DIV(msg_timing, clk_div_exp);
+
+	return DIV_ROUND_UP_ULL(prate, div);
+}
+
+static const struct clk_ops clk_aspeed_peci_ops = {
+	.set_rate = clk_aspeed_peci_set_rate,
+	.determine_rate = clk_aspeed_peci_determine_rate,
+	.recalc_rate = clk_aspeed_peci_recalc_rate,
+};
+
+/*
+ * PECI HW contains a clock divider which is a combination of:
+ *  div0: 4 (fixed divider)
+ *  div1: x + 1
+ *  div2: 1 << y
+ * In other words, out_clk = in_clk / (div0 * div1 * div2)
+ * The resulting frequency is used by PECI Controller to drive the PECI bus to
+ * negotiate optimal transfer rate.
+ */
+static struct clk *devm_aspeed_peci_register_clk_div(struct device *dev, struct clk *parent,
+						     struct aspeed_peci *priv)
+{
+	struct clk_aspeed_peci *peci_clk;
+	struct clk_init_data init;
+	const char *parent_name;
+	char name[32];
+	int ret;
+
+	snprintf(name, sizeof(name), "%s_div", dev_name(dev));
+
+	parent_name = __clk_get_name(parent);
+
+	init.ops = &clk_aspeed_peci_ops;
+	init.name = name;
+	init.parent_names = (const char* []) { parent_name };
+	init.num_parents = 1;
+	init.flags = 0;
+
+	peci_clk = devm_kzalloc(dev, sizeof(struct clk_aspeed_peci), GFP_KERNEL);
+	if (!peci_clk)
+		return ERR_PTR(-ENOMEM);
+
+	peci_clk->hw.init = &init;
+	peci_clk->aspeed_peci = priv;
+
+	ret = devm_clk_hw_register(dev, &peci_clk->hw);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return peci_clk->hw.clk;
+}
+
+static void aspeed_peci_property_sanitize(struct device *dev, const char *propname,
+					  u32 min, u32 max, u32 default_val, u32 *propval)
+{
+	u32 val;
+	int ret;
+
+	ret = device_property_read_u32(dev, propname, &val);
+	if (ret) {
+		val = default_val;
+	} else if (val > max || val < min) {
+		dev_warn(dev, "invalid %s: %u, falling back to: %u\n",
+			 propname, val, default_val);
+
+		val = default_val;
+	}
+
+	*propval = val;
+}
+
+static void aspeed_peci_property_setup(struct aspeed_peci *priv)
+{
+	aspeed_peci_property_sanitize(priv->dev, "clock-frequency",
+				      ASPEED_PECI_CLK_FREQUENCY_MIN, ASPEED_PECI_CLK_FREQUENCY_MAX,
+				      ASPEED_PECI_CLK_FREQUENCY_DEFAULT, &priv->clk_frequency);
+	aspeed_peci_property_sanitize(priv->dev, "cmd-timeout-ms",
+				      1, ASPEED_PECI_CMD_TIMEOUT_MS_MAX,
+				      ASPEED_PECI_CMD_TIMEOUT_MS_DEFAULT, &priv->cmd_timeout_ms);
+}
+
+static const struct peci_controller_ops aspeed_ops = {
+	.xfer = aspeed_peci_xfer,
+};
+
+static void aspeed_peci_reset_control_release(void *data)
+{
+	reset_control_assert(data);
+}
+
+static int devm_aspeed_peci_reset_control_deassert(struct device *dev, struct reset_control *rst)
+{
+	int ret;
+
+	ret = reset_control_deassert(rst);
+	if (ret)
+		return ret;
+
+	return devm_add_action_or_reset(dev, aspeed_peci_reset_control_release, rst);
+}
+
+static void aspeed_peci_clk_release(void *data)
+{
+	clk_disable_unprepare(data);
+}
+
+static int devm_aspeed_peci_clk_enable(struct device *dev, struct clk *clk)
+{
+	int ret;
+
+	ret = clk_prepare_enable(clk);
+	if (ret)
+		return ret;
+
+	return devm_add_action_or_reset(dev, aspeed_peci_clk_release, clk);
+}
+
+static int aspeed_peci_probe(struct platform_device *pdev)
+{
+	struct peci_controller *controller;
+	struct aspeed_peci *priv;
+	struct clk *ref_clk;
+	int ret;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->dev = &pdev->dev;
+	dev_set_drvdata(priv->dev, priv);
+
+	priv->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(priv->base))
+		return PTR_ERR(priv->base);
+
+	priv->irq = platform_get_irq(pdev, 0);
+	if (priv->irq < 0)
+		return priv->irq;
+
+	ret = devm_request_irq(&pdev->dev, priv->irq, aspeed_peci_irq_handler,
+			       0, "peci-aspeed", priv);
+	if (ret)
+		return ret;
+
+	init_completion(&priv->xfer_complete);
+	spin_lock_init(&priv->lock);
+
+	priv->rst = devm_reset_control_get(&pdev->dev, NULL);
+	if (IS_ERR(priv->rst))
+		return dev_err_probe(priv->dev, PTR_ERR(priv->rst),
+				     "failed to get reset control\n");
+
+	ret = devm_aspeed_peci_reset_control_deassert(priv->dev, priv->rst);
+	if (ret)
+		return dev_err_probe(priv->dev, ret, "cannot deassert reset control\n");
+
+	aspeed_peci_property_setup(priv);
+
+	aspeed_peci_init_regs(priv);
+
+	ref_clk = devm_clk_get(priv->dev, NULL);
+	if (IS_ERR(ref_clk))
+		return dev_err_probe(priv->dev, PTR_ERR(ref_clk), "failed to get ref clock\n");
+
+	priv->clk = devm_aspeed_peci_register_clk_div(priv->dev, ref_clk, priv);
+	if (IS_ERR(priv->clk))
+		return dev_err_probe(priv->dev, PTR_ERR(priv->clk), "cannot register clock\n");
+
+	ret = clk_set_rate(priv->clk, priv->clk_frequency);
+	if (ret < 0)
+		return dev_err_probe(priv->dev, ret, "cannot set clock frequency\n");
+
+	ret = devm_aspeed_peci_clk_enable(priv->dev, priv->clk);
+	if (ret)
+		return dev_err_probe(priv->dev, ret, "failed to enable clock\n");
+
+	aspeed_peci_controller_enable(priv);
+
+	controller = devm_peci_controller_add(priv->dev, &aspeed_ops);
+	if (IS_ERR(controller))
+		return dev_err_probe(priv->dev, PTR_ERR(controller),
+				     "failed to add aspeed peci controller\n");
+
+	priv->controller = controller;
+
+	return 0;
+}
+
+static const struct of_device_id aspeed_peci_of_table[] = {
+	{ .compatible = "aspeed,ast2400-peci", },
+	{ .compatible = "aspeed,ast2500-peci", },
+	{ .compatible = "aspeed,ast2600-peci", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, aspeed_peci_of_table);
+
+static struct platform_driver aspeed_peci_driver = {
+	.probe  = aspeed_peci_probe,
+	.driver = {
+		.name           = "peci-aspeed",
+		.of_match_table = aspeed_peci_of_table,
+	},
+};
+module_platform_driver(aspeed_peci_driver);
+
+MODULE_AUTHOR("Ryan Chen <ryan_chen@aspeedtech.com>");
+MODULE_AUTHOR("Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>");
+MODULE_DESCRIPTION("ASPEED PECI driver");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS("PECI");
diff --git a/drivers/peci/controller/peci-npcm.c b/drivers/peci/controller/peci-npcm.c
new file mode 100644
index 000000000..931868991
--- /dev/null
+++ b/drivers/peci/controller/peci-npcm.c
@@ -0,0 +1,297 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2019 Nuvoton Technology corporation
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/peci.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+
+/* NPCM GCR module */
+#define NPCM_INTCR3_OFFSET	0x9C
+#define NPCM_INTCR3_PECIVSEL	BIT(19)
+
+/* NPCM PECI Registers */
+#define NPCM_PECI_CTL_STS	0x00
+#define NPCM_PECI_RD_LENGTH	0x04
+#define NPCM_PECI_ADDR		0x08
+#define NPCM_PECI_CMD		0x0C
+#define NPCM_PECI_CTL2		0x10
+#define NPCM_PECI_WR_LENGTH	0x1C
+#define NPCM_PECI_PDDR		0x2C
+#define NPCM_PECI_DAT_INOUT(n)	(0x100 + ((n) * 4))
+
+#define NPCM_PECI_MAX_REG	0x200
+
+/* NPCM_PECI_CTL_STS - 0x00 : Control Register */
+#define NPCM_PECI_CTRL_DONE_INT_EN	BIT(6)
+#define NPCM_PECI_CTRL_ABRT_ERR		BIT(4)
+#define NPCM_PECI_CTRL_CRC_ERR		BIT(3)
+#define NPCM_PECI_CTRL_DONE		BIT(1)
+#define NPCM_PECI_CTRL_START_BUSY	BIT(0)
+
+/* NPCM_PECI_RD_LENGTH - 0x04 : Command Register */
+#define NPCM_PECI_RD_LEN_MASK		GENMASK(6, 0)
+
+/* NPCM_PECI_CMD - 0x10 : Command Register */
+#define NPCM_PECI_CTL2_MASK		GENMASK(7, 6)
+
+/* NPCM_PECI_WR_LENGTH - 0x1C : Command Register */
+#define NPCM_PECI_WR_LEN_MASK		GENMASK(6, 0)
+
+/* NPCM_PECI_PDDR - 0x2C : Command Register */
+#define NPCM_PECI_PDDR_MASK		GENMASK(4, 0)
+
+#define NPCM_PECI_INT_MASK		(NPCM_PECI_CTRL_ABRT_ERR | \
+					 NPCM_PECI_CTRL_CRC_ERR  | \
+					 NPCM_PECI_CTRL_DONE)
+
+#define NPCM_PECI_IDLE_CHECK_TIMEOUT_USEC	(50 * USEC_PER_MSEC)
+#define NPCM_PECI_IDLE_CHECK_INTERVAL_USEC	(10 * USEC_PER_MSEC)
+#define NPCM_PECI_CMD_TIMEOUT_MS_DEFAULT	1000
+#define NPCM_PECI_CMD_TIMEOUT_MS_MAX		60000
+#define NPCM_PECI_HOST_NEG_BIT_RATE_DEFAULT	15
+#define NPCM_PECI_PULL_DOWN_DEFAULT		0
+
+struct npcm_peci {
+	u32			cmd_timeout_ms;
+	struct completion	xfer_complete;
+	struct regmap		*regmap;
+	u32			status;
+	spinlock_t		lock; /* to sync completion status handling */
+	struct peci_controller *controller;
+	struct device		*dev;
+	struct clk		*clk;
+	int			irq;
+};
+
+static int npcm_peci_xfer(struct peci_controller *controller, u8 addr, struct peci_request *req)
+{
+	struct npcm_peci *priv = dev_get_drvdata(controller->dev.parent);
+	unsigned long timeout = msecs_to_jiffies(priv->cmd_timeout_ms);
+	unsigned int msg_rd;
+	u32 cmd_sts;
+	int i, ret;
+
+	/* Check command sts and bus idle state */
+	ret = regmap_read_poll_timeout(priv->regmap, NPCM_PECI_CTL_STS, cmd_sts,
+				       !(cmd_sts & NPCM_PECI_CTRL_START_BUSY),
+				       NPCM_PECI_IDLE_CHECK_INTERVAL_USEC,
+				       NPCM_PECI_IDLE_CHECK_TIMEOUT_USEC);
+	if (ret)
+		return ret; /* -ETIMEDOUT */
+
+	spin_lock_irq(&priv->lock);
+	reinit_completion(&priv->xfer_complete);
+
+	regmap_write(priv->regmap, NPCM_PECI_ADDR, addr);
+	regmap_write(priv->regmap, NPCM_PECI_RD_LENGTH, NPCM_PECI_WR_LEN_MASK & req->rx.len);
+	regmap_write(priv->regmap, NPCM_PECI_WR_LENGTH, NPCM_PECI_WR_LEN_MASK & req->tx.len);
+
+	if (req->tx.len) {
+		regmap_write(priv->regmap, NPCM_PECI_CMD, req->tx.buf[0]);
+
+		for (i = 0; i < (req->tx.len - 1); i++)
+			regmap_write(priv->regmap, NPCM_PECI_DAT_INOUT(i), req->tx.buf[i + 1]);
+	}
+
+#if IS_ENABLED(CONFIG_DYNAMIC_DEBUG)
+	dev_dbg(priv->dev, "addr : %#02x, tx.len : %#02x, rx.len : %#02x\n",
+		addr, req->tx.len, req->rx.len);
+	print_hex_dump_bytes("TX : ", DUMP_PREFIX_NONE, req->tx.buf, req->tx.len);
+#endif
+
+	priv->status = 0;
+	regmap_update_bits(priv->regmap, NPCM_PECI_CTL_STS, NPCM_PECI_CTRL_START_BUSY,
+			   NPCM_PECI_CTRL_START_BUSY);
+
+	spin_unlock_irq(&priv->lock);
+
+	ret = wait_for_completion_interruptible_timeout(&priv->xfer_complete, timeout);
+	if (ret < 0)
+		return ret;
+
+	if (ret == 0) {
+		dev_dbg(priv->dev, "timeout waiting for a response\n");
+		return -ETIMEDOUT;
+	}
+
+	spin_lock_irq(&priv->lock);
+
+	if (priv->status != NPCM_PECI_CTRL_DONE) {
+		spin_unlock_irq(&priv->lock);
+		dev_dbg(priv->dev, "no valid response, status: %#02x\n", priv->status);
+		return -EIO;
+	}
+
+	regmap_write(priv->regmap, NPCM_PECI_CMD, 0);
+
+	for (i = 0; i < req->rx.len; i++) {
+		regmap_read(priv->regmap, NPCM_PECI_DAT_INOUT(i), &msg_rd);
+		req->rx.buf[i] = (u8)msg_rd;
+	}
+
+	spin_unlock_irq(&priv->lock);
+
+#if IS_ENABLED(CONFIG_DYNAMIC_DEBUG)
+	print_hex_dump_bytes("RX : ", DUMP_PREFIX_NONE, req->rx.buf, req->rx.len);
+#endif
+	return 0;
+}
+
+static irqreturn_t npcm_peci_irq_handler(int irq, void *arg)
+{
+	struct npcm_peci *priv = arg;
+	u32 status_ack = 0;
+	u32 status;
+
+	spin_lock(&priv->lock);
+	regmap_read(priv->regmap, NPCM_PECI_CTL_STS, &status);
+	priv->status |= (status & NPCM_PECI_INT_MASK);
+
+	if (status & NPCM_PECI_CTRL_CRC_ERR)
+		status_ack |= NPCM_PECI_CTRL_CRC_ERR;
+
+	if (status & NPCM_PECI_CTRL_ABRT_ERR)
+		status_ack |= NPCM_PECI_CTRL_ABRT_ERR;
+
+	/*
+	 * All commands should be ended up with a NPCM_PECI_CTRL_DONE
+	 * bit set even in an error case.
+	 */
+	if (status & NPCM_PECI_CTRL_DONE) {
+		status_ack |= NPCM_PECI_CTRL_DONE;
+		complete(&priv->xfer_complete);
+	}
+
+	regmap_write_bits(priv->regmap, NPCM_PECI_CTL_STS, NPCM_PECI_INT_MASK, status_ack);
+
+	spin_unlock(&priv->lock);
+	return IRQ_HANDLED;
+}
+
+static int npcm_peci_init_ctrl(struct npcm_peci *priv)
+{
+	u32 cmd_sts;
+	int ret;
+
+	priv->clk = devm_clk_get_enabled(priv->dev, NULL);
+	if (IS_ERR(priv->clk)) {
+		dev_err(priv->dev, "failed to get ref clock\n");
+		return PTR_ERR(priv->clk);
+	}
+
+	ret = device_property_read_u32(priv->dev, "cmd-timeout-ms", &priv->cmd_timeout_ms);
+	if (ret) {
+		priv->cmd_timeout_ms = NPCM_PECI_CMD_TIMEOUT_MS_DEFAULT;
+	} else if (priv->cmd_timeout_ms > NPCM_PECI_CMD_TIMEOUT_MS_MAX ||
+		   priv->cmd_timeout_ms == 0) {
+		dev_warn(priv->dev, "invalid cmd-timeout-ms: %u, falling back to: %u\n",
+			 priv->cmd_timeout_ms, NPCM_PECI_CMD_TIMEOUT_MS_DEFAULT);
+
+		priv->cmd_timeout_ms = NPCM_PECI_CMD_TIMEOUT_MS_DEFAULT;
+	}
+
+	regmap_update_bits(priv->regmap, NPCM_PECI_CTL2, NPCM_PECI_CTL2_MASK,
+			   NPCM_PECI_PULL_DOWN_DEFAULT << 6);
+
+	regmap_update_bits(priv->regmap, NPCM_PECI_PDDR, NPCM_PECI_PDDR_MASK,
+			   NPCM_PECI_HOST_NEG_BIT_RATE_DEFAULT);
+
+	ret = regmap_read_poll_timeout(priv->regmap, NPCM_PECI_CTL_STS, cmd_sts,
+				       !(cmd_sts & NPCM_PECI_CTRL_START_BUSY),
+				       NPCM_PECI_IDLE_CHECK_INTERVAL_USEC,
+				       NPCM_PECI_IDLE_CHECK_TIMEOUT_USEC);
+	if (ret)
+		return ret; /* -ETIMEDOUT */
+
+	/* PECI interrupt enable */
+	regmap_update_bits(priv->regmap, NPCM_PECI_CTL_STS, NPCM_PECI_CTRL_DONE_INT_EN,
+			   NPCM_PECI_CTRL_DONE_INT_EN);
+
+	return 0;
+}
+
+static const struct regmap_config npcm_peci_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = NPCM_PECI_MAX_REG,
+};
+
+static const struct peci_controller_ops npcm_ops = {
+	.xfer = npcm_peci_xfer,
+};
+
+static int npcm_peci_probe(struct platform_device *pdev)
+{
+	struct peci_controller *controller;
+	struct npcm_peci *priv;
+	void __iomem *base;
+	int ret;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->dev = &pdev->dev;
+	dev_set_drvdata(&pdev->dev, priv);
+
+	base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	priv->regmap = devm_regmap_init_mmio(&pdev->dev, base, &npcm_peci_regmap_config);
+	if (IS_ERR(priv->regmap))
+		return PTR_ERR(priv->regmap);
+
+	priv->irq = platform_get_irq(pdev, 0);
+	if (priv->irq < 0)
+		return priv->irq;
+
+	ret = devm_request_irq(&pdev->dev, priv->irq, npcm_peci_irq_handler,
+			       0, "peci-npcm-irq", priv);
+	if (ret)
+		return ret;
+
+	init_completion(&priv->xfer_complete);
+	spin_lock_init(&priv->lock);
+
+	ret = npcm_peci_init_ctrl(priv);
+	if (ret)
+		return ret;
+
+	controller = devm_peci_controller_add(priv->dev, &npcm_ops);
+	if (IS_ERR(controller))
+		return dev_err_probe(priv->dev, PTR_ERR(controller),
+				     "failed to add npcm peci controller\n");
+
+	priv->controller = controller;
+
+	return 0;
+}
+
+static const struct of_device_id npcm_peci_of_table[] = {
+	{ .compatible = "nuvoton,npcm750-peci", },
+	{ .compatible = "nuvoton,npcm845-peci", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, npcm_peci_of_table);
+
+static struct platform_driver npcm_peci_driver = {
+	.probe  = npcm_peci_probe,
+	.driver = {
+		.name           = KBUILD_MODNAME,
+		.of_match_table = npcm_peci_of_table,
+	},
+};
+module_platform_driver(npcm_peci_driver);
+
+MODULE_AUTHOR("Tomer Maimon <tomer.maimon@nuvoton.com>");
+MODULE_DESCRIPTION("NPCM PECI driver");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS("PECI");