kbuild: rust: keep Rust objects out of Clang LTO with inline helpersgrafted

Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit
`objtool` errors such as:

    vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a:
    can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd

The reason is that in such builds, the Clang invocation that compiles
the combined Rust plus helpers bitcode emits LLVM bitcode (again) --
the final code generation happens in the linker's LTO step, which the
`-mllvm` trap options passed to Clang do not reach.

This, in turn, means that unreachable traps are missing, and the
impossible paths do not merely fallthrough to the next symbol, but past
the end of their own section, since LTO builds place each function in
its own section.

Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always
emits machine code directly, with the traps in place.

Assisted-by: LLM
Cc: Gary Guo <gary@garyguo.net>
Cc: Boqun Feng <boqun@kernel.org>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Matthew Maurer <mmaurer@google.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust")
Acked-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

1 files changed, 631 insertions, 0 deletions

diff --git a/drivers/edac/imh_base.c b/drivers/edac/imh_base.c
new file mode 100644
index 000000000..6ca0df031
--- /dev/null
+++ b/drivers/edac/imh_base.c
@@ -0,0 +1,631 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for Intel(R) servers with Integrated Memory/IO Hub-based memory controller.
+ * Copyright (c) 2025, Intel Corporation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/io.h>
+#include <asm/cpu_device_id.h>
+#include <asm/intel-family.h>
+#include <asm/mce.h>
+#include <asm/cpu.h>
+#include "edac_module.h"
+#include "skx_common.h"
+
+#define IMH_REVISION	"v0.0.1"
+#define EDAC_MOD_STR	"imh_edac"
+
+/* Debug macros */
+#define imh_printk(level, fmt, arg...)	\
+	edac_printk(level, "imh", fmt, ##arg)
+
+/* Configuration Agent(Ubox) */
+#define MMIO_BASE_H(reg)		(((u64)GET_BITFIELD(reg, 0, 29)) << 23)
+#define SOCKET_ID(reg)			GET_BITFIELD(reg, 0, 3)
+
+/* PUNIT */
+#define DDR_IMC_BITMAP(reg)		GET_BITFIELD(reg, 23, 30)
+
+/* Memory Controller */
+#define ECC_ENABLED(reg)		GET_BITFIELD(reg, 2, 2)
+#define DIMM_POPULATED(reg)		GET_BITFIELD(reg, 15, 15)
+
+/* System Cache Agent(SCA) */
+#define TOLM(reg)			(((u64)GET_BITFIELD(reg, 16, 31)) << 16)
+#define TOHM(reg)			(((u64)GET_BITFIELD(reg, 16, 51)) << 16)
+
+/* Home Agent (HA) */
+#define NMCACHING(reg)			GET_BITFIELD(reg, 8, 8)
+
+/**
+ * struct local_reg - A register as described in the local package view.
+ *
+ * @pkg: (input)	The package where the register is located.
+ * @pbase: (input)	The IP MMIO base physical address in the local package view.
+ * @size: (input)	The IP MMIO size.
+ * @offset: (input)	The register offset from the IP MMIO base @pbase.
+ * @width: (input)	The register width in byte.
+ * @vbase: (internal)	The IP MMIO base virtual address.
+ * @val: (output)	The register value.
+ */
+struct local_reg {
+	int pkg;
+	u64 pbase;
+	u32 size;
+	u32 offset;
+	u8  width;
+	void __iomem *vbase;
+	u64 val;
+};
+
+#define DEFINE_LOCAL_REG(name, cfg, package, north, ip_name, ip_idx, reg_name)	\
+	struct local_reg name = {						\
+		.pkg	= package,						\
+		.pbase	= (north ? (cfg)->mmio_base_l_north :			\
+			  (cfg)->mmio_base_l_south) +				\
+			  (cfg)->ip_name##_base +				\
+			  (cfg)->ip_name##_size * (ip_idx),			\
+		.size	= (cfg)->ip_name##_size,				\
+		.offset	= (cfg)->ip_name##_reg_##reg_name##_offset,		\
+		.width	= (cfg)->ip_name##_reg_##reg_name##_width,		\
+	}
+
+static struct res_config *res_cfg;
+static int retry_rd_err_log;
+
+#define REG_RRL_DEFINE(a0, a1, a2, a3, a4, a5, a6, b0, b1, b2, b3)	\
+	{								\
+		.set_num = 4,						\
+		.reg_num = 7,						\
+		.sources = {RRL_SRC_FRE_SCRUB, RRL_SRC_FRE_DEMAND, RRL_SRC_LRE_SCRUB, RRL_SRC_LRE_DEMAND},	\
+		.offsets = {									\
+			{a0,      a1,      a2,      a3,      a4,      a5,      a6},		\
+			{a0 + 4,  a1 + 4,  a2 + 8,  a3 + 4,  a4 + 4,  a5 + 8,  a6 + 8},		\
+			{a0 + 8,  a1 + 8,  a2 + 16, a3 + 8,  a4 + 8,  a5 + 16, a6 + 16},	\
+			{a0 + 12, a1 + 12, a2 + 24, a3 + 12, a4 + 12, a5 + 24, a6 + 24},	\
+		},										\
+		.widths		= {4, 4, 8, 4, 4, 8, 8},		\
+		.v_mask		= BIT(0),				\
+		.uc_mask	= BIT(1),				\
+		.over_mask	= BIT(2),				\
+		.en_mask	= BIT(12),				\
+		.en_patspr_mask	= BIT(14),				\
+		.noover_mask	= BIT(15),				\
+		.cecnt_num	= 4,					\
+		.cecnt_offsets	= {b0, b1, b2, b3},			\
+		.cecnt_widths	= {8, 8, 8, 8},				\
+}
+
+static struct reg_rrl dmr_reg_rrl_ddr_subch0 = REG_RRL_DEFINE(
+	0x2dc0, 0x2dd0, 0x2de0, 0x2e00, 0x2e10, 0x2f70, 0x0200,
+	0x2c10, 0x2c18, 0x2c20, 0x2c28);
+static struct reg_rrl dmr_reg_rrl_ddr_subch1 = REG_RRL_DEFINE(
+	0x6dc0, 0x6dd0, 0x6de0, 0x6e00, 0x6e10, 0x6f70, 0x4200,
+	0x6c10, 0x6c18, 0x6c20, 0x6c28);
+
+static void __read_local_reg(void *reg)
+{
+	struct local_reg *r = (struct local_reg *)reg;
+
+	r->val = skx_readx(r->vbase + r->offset, r->width);
+}
+
+/* Read a local-view register. */
+static bool read_local_reg(struct local_reg *reg)
+{
+	int cpu;
+
+	/* Get the target CPU in the package @reg->pkg. */
+	for_each_online_cpu(cpu) {
+		if (reg->pkg == topology_physical_package_id(cpu))
+			break;
+	}
+
+	if (cpu >= nr_cpu_ids)
+		return false;
+
+	reg->vbase = ioremap(reg->pbase, reg->size);
+	if (!reg->vbase) {
+		imh_printk(KERN_ERR, "Failed to ioremap 0x%llx\n", reg->pbase);
+		return false;
+	}
+
+	/* Get the target CPU to read the register. */
+	smp_call_function_single(cpu, __read_local_reg, reg, 1);
+	iounmap(reg->vbase);
+
+	return true;
+}
+
+/* Get the bitmap of memory controller instances in package @pkg. */
+static u32 get_imc_bitmap(struct res_config *cfg, int pkg, bool north)
+{
+	DEFINE_LOCAL_REG(reg, cfg, pkg, north, pcu, 0, capid3);
+
+	if (!read_local_reg(&reg))
+		return 0;
+
+	edac_dbg(2, "Pkg%d %s mc instances bitmap 0x%llx (reg 0x%llx)\n",
+		 pkg, north ? "north" : "south",
+		 DDR_IMC_BITMAP(reg.val), reg.val);
+
+	return DDR_IMC_BITMAP(reg.val);
+}
+
+static void imc_release(struct device *dev)
+{
+	edac_dbg(2, "imc device %s released\n", dev_name(dev));
+	kfree(dev);
+}
+
+static int __get_ddr_munits(struct res_config *cfg, struct skx_dev *d,
+			    bool north, int lmc)
+{
+	unsigned long size = cfg->ddr_chan_mmio_sz * cfg->ddr_chan_num;
+	unsigned long bitmap = get_imc_bitmap(cfg, d->pkg, north);
+	void __iomem *mbase;
+	struct device *dev;
+	int i, rc, pmc;
+	u64 base;
+
+	for_each_set_bit(i, &bitmap, sizeof(bitmap) * 8) {
+		base  = north ? d->mmio_base_h_north : d->mmio_base_h_south;
+		base += cfg->ddr_imc_base + size * i;
+
+		edac_dbg(2, "Pkg%d mc%d mmio base 0x%llx size 0x%lx\n",
+			 d->pkg, lmc, base, size);
+
+		/* Set up the imc MMIO. */
+		mbase = ioremap(base, size);
+		if (!mbase) {
+			imh_printk(KERN_ERR, "Failed to ioremap 0x%llx\n", base);
+			return -ENOMEM;
+		}
+
+		d->imc[lmc].mbase = mbase;
+		d->imc[lmc].lmc = lmc;
+
+		/* Create the imc device instance. */
+		dev = kzalloc_obj(*dev);
+		if (!dev)
+			return -ENOMEM;
+
+		dev->release = imc_release;
+		device_initialize(dev);
+		rc = dev_set_name(dev, "0x%llx", base);
+		if (rc) {
+			imh_printk(KERN_ERR, "Failed to set dev name\n");
+			put_device(dev);
+			return rc;
+		}
+
+		d->imc[lmc].dev = dev;
+
+		/* Set up the imc index mapping. */
+		pmc = north ? i : 8 + i;
+		skx_set_mc_mapping(d, pmc, lmc);
+
+		lmc++;
+	}
+
+	return lmc;
+}
+
+static bool get_ddr_munits(struct res_config *cfg, struct skx_dev *d)
+{
+	int lmc = __get_ddr_munits(cfg, d, true, 0);
+
+	if (lmc < 0)
+		return false;
+
+	lmc = __get_ddr_munits(cfg, d, false, lmc);
+	if (lmc <= 0)
+		return false;
+
+	return true;
+}
+
+static bool get_socket_id(struct res_config *cfg, struct skx_dev *d)
+{
+	DEFINE_LOCAL_REG(reg, cfg, d->pkg, true, ubox, 0, socket_id);
+	u8 src_id;
+	int i;
+
+	if (!read_local_reg(&reg))
+		return false;
+
+	src_id = SOCKET_ID(reg.val);
+	edac_dbg(2, "socket id 0x%x (reg 0x%llx)\n", src_id, reg.val);
+
+	for (i = 0; i < cfg->ddr_imc_num; i++)
+		d->imc[i].src_id   = src_id;
+
+	return true;
+}
+
+/* Get TOLM (Top Of Low Memory) and TOHM (Top Of High Memory) parameters. */
+static bool imh_get_tolm_tohm(struct res_config *cfg, u64 *tolm, u64 *tohm)
+{
+	DEFINE_LOCAL_REG(reg, cfg, 0, true, sca, 0, tolm);
+
+	if (!read_local_reg(&reg))
+		return false;
+
+	*tolm = TOLM(reg.val);
+	edac_dbg(2, "tolm 0x%llx (reg 0x%llx)\n", *tolm, reg.val);
+
+	DEFINE_LOCAL_REG(reg2, cfg, 0, true, sca, 0, tohm);
+
+	if (!read_local_reg(&reg2))
+		return false;
+
+	*tohm = TOHM(reg2.val);
+	edac_dbg(2, "tohm 0x%llx (reg 0x%llx)\n", *tohm, reg2.val);
+
+	return true;
+}
+
+/* Get the system-view MMIO_BASE_H for {north,south}-IMH. */
+static int imh_get_all_mmio_base_h(struct res_config *cfg, struct list_head *edac_list)
+{
+	int i, n = topology_max_packages(), imc_num = cfg->ddr_imc_num + cfg->hbm_imc_num;
+	struct skx_dev *d;
+
+	for (i = 0; i < n; i++) {
+		d = kzalloc_flex(*d, imc, imc_num);
+		if (!d)
+			return -ENOMEM;
+
+		DEFINE_LOCAL_REG(reg, cfg, i, true, ubox, 0, mmio_base);
+
+		/* Get MMIO_BASE_H for the north-IMH. */
+		if (!read_local_reg(&reg) || !reg.val) {
+			kfree(d);
+			imh_printk(KERN_ERR, "Pkg%d has no north mmio_base_h\n", i);
+			return -ENODEV;
+		}
+
+		d->mmio_base_h_north = MMIO_BASE_H(reg.val);
+		edac_dbg(2, "Pkg%d north mmio_base_h 0x%llx (reg 0x%llx)\n",
+			 i, d->mmio_base_h_north, reg.val);
+
+		/* Get MMIO_BASE_H for the south-IMH (optional). */
+		DEFINE_LOCAL_REG(reg2, cfg, i, false, ubox, 0, mmio_base);
+
+		if (read_local_reg(&reg2)) {
+			d->mmio_base_h_south = MMIO_BASE_H(reg2.val);
+			edac_dbg(2, "Pkg%d south mmio_base_h 0x%llx (reg 0x%llx)\n",
+				 i, d->mmio_base_h_south, reg2.val);
+		}
+
+		d->pkg = i;
+		d->num_imc = imc_num;
+		skx_init_mc_mapping(d);
+		list_add_tail(&d->list, edac_list);
+	}
+
+	return 0;
+}
+
+/* Get the number of per-package memory controllers. */
+static int imh_get_imc_num(struct res_config *cfg)
+{
+	int imc_num = hweight32(get_imc_bitmap(cfg, 0, true)) +
+		      hweight32(get_imc_bitmap(cfg, 0, false));
+
+	if (!imc_num) {
+		imh_printk(KERN_ERR, "Invalid mc number\n");
+		return -ENODEV;
+	}
+
+	if (cfg->ddr_imc_num != imc_num) {
+		/*
+		 * Update the configuration data to reflect the number of
+		 * present DDR memory controllers.
+		 */
+		cfg->ddr_imc_num = imc_num;
+		edac_dbg(2, "Set ddr mc number %d\n", imc_num);
+	}
+
+	return 0;
+}
+
+/* Get all memory controllers' parameters. */
+static int imh_get_munits(struct res_config *cfg, struct list_head *edac_list)
+{
+	struct skx_imc *imc;
+	struct skx_dev *d;
+	u8 mc = 0;
+	int i;
+
+	list_for_each_entry(d, edac_list, list) {
+		if (!get_ddr_munits(cfg, d)) {
+			imh_printk(KERN_ERR, "No mc found\n");
+			return -ENODEV;
+		}
+
+		if (!get_socket_id(cfg, d)) {
+			imh_printk(KERN_ERR, "Failed to get socket id\n");
+			return -ENODEV;
+		}
+
+		for (i = 0; i < cfg->ddr_imc_num; i++) {
+			imc = &d->imc[i];
+			if (!imc->mbase)
+				continue;
+
+			imc->chan_mmio_sz = cfg->ddr_chan_mmio_sz;
+			imc->num_channels = cfg->ddr_chan_num;
+			imc->num_dimms    = cfg->ddr_dimm_num;
+			imc->mc		  = mc++;
+		}
+	}
+
+	return 0;
+}
+
+static bool check_2lm_enabled(struct res_config *cfg, struct skx_dev *d, int ha_idx)
+{
+	DEFINE_LOCAL_REG(reg, cfg, d->pkg, true, ha, ha_idx, mode);
+
+	if (!read_local_reg(&reg))
+		return false;
+
+	if (!NMCACHING(reg.val))
+		return false;
+
+	edac_dbg(2, "2-level memory configuration (reg 0x%llx, ha idx %d)\n", reg.val, ha_idx);
+	return true;
+}
+
+/* Check whether the system has a 2-level memory configuration. */
+static bool imh_2lm_enabled(struct res_config *cfg, struct list_head *head)
+{
+	struct skx_dev *d;
+	int i;
+
+	list_for_each_entry(d, head, list) {
+		for (i = 0; i < cfg->ddr_imc_num; i++)
+			if (check_2lm_enabled(cfg, d, i))
+				return true;
+	}
+
+	return false;
+}
+
+static u32 read_imc_mcmtr(struct res_config *cfg, struct skx_imc *imc, int chan)
+{
+	return (u32)skx_read_imc_reg(imc, chan, cfg->ddr_reg_mcmtr_offset, cfg->ddr_reg_mcmtr_width);
+}
+
+static u32 read_imc_dimmmtr(struct res_config *cfg, struct skx_imc *imc, int chan, int dimm)
+{
+	return (u32)skx_read_imc_reg(imc, chan, cfg->ddr_reg_dimmmtr_offset +
+				     cfg->ddr_reg_dimmmtr_width * dimm,
+				     cfg->ddr_reg_dimmmtr_width);
+}
+
+static bool ecc_enabled(u32 mcmtr)
+{
+	return (bool)ECC_ENABLED(mcmtr);
+}
+
+static bool dimm_populated(u32 dimmmtr)
+{
+	return (bool)DIMM_POPULATED(dimmmtr);
+}
+
+/* Get each DIMM's configurations of the memory controller @mci. */
+static int imh_get_dimm_config(struct mem_ctl_info *mci, struct res_config *cfg)
+{
+	struct skx_pvt *pvt = mci->pvt_info;
+	struct skx_imc *imc = pvt->imc;
+	struct dimm_info *dimm;
+	u32 mcmtr, dimmmtr;
+	int i, j, ndimms;
+
+	for (i = 0; i < imc->num_channels; i++) {
+		if (!imc->mbase)
+			continue;
+
+		mcmtr = read_imc_mcmtr(cfg, imc, i);
+
+		for (ndimms = 0, j = 0; j < imc->num_dimms; j++) {
+			dimmmtr = read_imc_dimmmtr(cfg, imc, i, j);
+			edac_dbg(1, "mcmtr 0x%x dimmmtr 0x%x (mc%d ch%d dimm%d)\n",
+				 mcmtr, dimmmtr, imc->mc, i, j);
+
+			if (!dimm_populated(dimmmtr))
+				continue;
+
+			dimm = edac_get_dimm(mci, i, j, 0);
+			ndimms += skx_get_dimm_info(dimmmtr, 0, 0, dimm,
+						    imc, i, j, cfg);
+		}
+
+		if (ndimms && !ecc_enabled(mcmtr)) {
+			imh_printk(KERN_ERR, "ECC is disabled on mc%d ch%d\n",
+				   imc->mc, i);
+			return -ENODEV;
+		}
+	}
+
+	return 0;
+}
+
+/* Register all memory controllers to the EDAC core. */
+static int imh_register_mci(struct res_config *cfg, struct list_head *edac_list)
+{
+	struct skx_imc *imc;
+	struct skx_dev *d;
+	int i, rc;
+
+	list_for_each_entry(d, edac_list, list) {
+		for (i = 0; i < cfg->ddr_imc_num; i++) {
+			imc = &d->imc[i];
+			if (!imc->mbase)
+				continue;
+
+			rc = skx_register_mci(imc, imc->dev,
+					      dev_name(imc->dev),
+					      "Intel IMH-based Socket",
+					      EDAC_MOD_STR,
+					      imh_get_dimm_config, cfg);
+			if (rc)
+				return rc;
+		}
+	}
+
+	return 0;
+}
+
+static struct res_config dmr_cfg = {
+	.type				= DMR,
+	.support_ddr5			= true,
+	.mmio_base_l_north		= 0xf6800000,
+	.mmio_base_l_south		= 0xf6000000,
+	.ddr_chan_num			= 1,
+	.ddr_dimm_num			= 2,
+	.ddr_imc_base			= 0x39b000,
+	.ddr_chan_mmio_sz		= 0x8000,
+	.ddr_reg_mcmtr_offset		= 0x360,
+	.ddr_reg_mcmtr_width		= 4,
+	.ddr_reg_dimmmtr_offset		= 0x370,
+	.ddr_reg_dimmmtr_width		= 4,
+	.ubox_base			= 0x0,
+	.ubox_size			= 0x2000,
+	.ubox_reg_mmio_base_offset	= 0x580,
+	.ubox_reg_mmio_base_width	= 4,
+	.ubox_reg_socket_id_offset	= 0x1080,
+	.ubox_reg_socket_id_width	= 4,
+	.pcu_base			= 0x3000,
+	.pcu_size			= 0x10000,
+	.pcu_reg_capid3_offset		= 0x290,
+	.pcu_reg_capid3_width		= 4,
+	.sca_base			= 0x24c000,
+	.sca_size			= 0x2500,
+	.sca_reg_tolm_offset		= 0x2100,
+	.sca_reg_tolm_width		= 8,
+	.sca_reg_tohm_offset		= 0x2108,
+	.sca_reg_tohm_width		= 8,
+	.ha_base			= 0x3eb000,
+	.ha_size			= 0x1000,
+	.ha_reg_mode_offset		= 0x4a0,
+	.ha_reg_mode_width		= 4,
+	.reg_rrl_ddr[0]			= &dmr_reg_rrl_ddr_subch0,
+	.reg_rrl_ddr[1]			= &dmr_reg_rrl_ddr_subch1,
+};
+
+static const struct x86_cpu_id imh_cpuids[] = {
+	X86_MATCH_VFM(INTEL_DIAMONDRAPIDS_X, &dmr_cfg),
+	{}
+};
+MODULE_DEVICE_TABLE(x86cpu, imh_cpuids);
+
+static struct notifier_block imh_mce_dec = {
+	.notifier_call	= skx_mce_check_error,
+	.priority	= MCE_PRIO_EDAC,
+};
+
+static int __init imh_init(void)
+{
+	const struct x86_cpu_id *id;
+	struct list_head *edac_list;
+	struct res_config *cfg;
+	const char *owner;
+	u64 tolm, tohm;
+	int rc;
+
+	edac_dbg(2, "\n");
+
+	if (ghes_get_devices())
+		return -EBUSY;
+
+	owner = edac_get_owner();
+	if (owner && strncmp(owner, EDAC_MOD_STR, sizeof(EDAC_MOD_STR)))
+		return -EBUSY;
+
+	if (cpu_feature_enabled(X86_FEATURE_HYPERVISOR))
+		return -ENODEV;
+
+	id = x86_match_cpu(imh_cpuids);
+	if (!id)
+		return -ENODEV;
+	cfg = (struct res_config *)id->driver_data;
+	skx_set_res_cfg(cfg);
+	res_cfg = cfg;
+
+	if (!imh_get_tolm_tohm(cfg, &tolm, &tohm))
+		return -ENODEV;
+
+	skx_set_hi_lo(tolm, tohm);
+
+	rc = imh_get_imc_num(cfg);
+	if (rc < 0)
+		goto fail;
+
+	edac_list = skx_get_edac_list();
+
+	rc = imh_get_all_mmio_base_h(cfg, edac_list);
+	if (rc)
+		goto fail;
+
+	rc = imh_get_munits(cfg, edac_list);
+	if (rc)
+		goto fail;
+
+	skx_set_mem_cfg(imh_2lm_enabled(cfg, edac_list));
+
+	rc = imh_register_mci(cfg, edac_list);
+	if (rc)
+		goto fail;
+
+	rc = skx_adxl_get();
+	if (rc)
+		goto fail;
+
+	opstate_init();
+	mce_register_decode_chain(&imh_mce_dec);
+	skx_setup_debug("imh_test");
+
+	cfg->rrl_ctrl_mode = retry_rd_err_log;
+	if (retry_rd_err_log && cfg->reg_rrl_ddr[0]) {
+		skx_set_show_rrl(skx_show_rrl);
+		if (retry_rd_err_log == RRL_CTRL_LINUX)
+			skx_enable_rrl(true);
+	}
+
+	imh_printk(KERN_INFO, "%s\n", IMH_REVISION);
+
+	return 0;
+fail:
+	skx_remove();
+	return rc;
+}
+
+static void __exit imh_exit(void)
+{
+	edac_dbg(2, "\n");
+
+	if (retry_rd_err_log && res_cfg->reg_rrl_ddr[0]) {
+		if (retry_rd_err_log == RRL_CTRL_LINUX)
+			skx_enable_rrl(false);
+		skx_set_show_rrl(NULL);
+	}
+
+	skx_teardown_debug();
+	mce_unregister_decode_chain(&imh_mce_dec);
+	skx_adxl_put();
+	skx_remove();
+}
+
+module_init(imh_init);
+module_exit(imh_exit);
+
+module_param(retry_rd_err_log, int, 0444);
+MODULE_PARM_DESC(retry_rd_err_log, "retry_rd_err_log: 0=off(default), 1=bios(Linux doesn't reset any control bits, but just reports values.), 2=linux(Linux tries to take control and resets mode bits, clear valid/UC bits after reading.)");
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Qiuxu Zhuo");
+MODULE_DESCRIPTION("MC Driver for Intel servers using IMH-based memory controller");