// SPDX-License-Identifier: GPL-2.0-only
/*
* dcdbas.c: Dell Systems Management Base Driver
*
* The Dell Systems Management Base Driver provides a sysfs interface for
* systems management software to perform System Management Interrupts (SMIs)
* and Host Control Actions (power cycle or power off after OS shutdown) on
* Dell systems.
*
* See Documentation/userspace-api/dcdbas.rst for more information.
*
* Copyright (C) 1995-2006 Dell Inc.
*/
#include <linux/platform_device.h>
#include <linux/acpi.h>
#include <linux/dma-mapping.h>
#include <linux/dmi.h>
#include <linux/errno.h>
#include <linux/cpu.h>
#include <linux/gfp.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/mc146818rtc.h>
#include <linux/module.h>
#include <linux/reboot.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/mutex.h>
#include "dcdbas.h"
#define DRIVER_NAME "dcdbas"
#define DRIVER_VERSION "5.6.0-3.4"
#define DRIVER_DESCRIPTION "Dell Systems Management Base Driver"
static struct platform_device *dcdbas_pdev;
static unsigned long max_smi_data_buf_size = MAX_SMI_DATA_BUF_SIZE;
static DEFINE_MUTEX(smi_data_lock);
static u8 *bios_buffer;
static struct smi_buffer smi_buf;
static unsigned int host_control_action;
static unsigned int host_control_smi_type;
static unsigned int host_control_on_shutdown;
static bool wsmt_enabled;
int dcdbas_smi_alloc(struct smi_buffer *smi_buffer, unsigned long size)
{
smi_buffer->virt = dma_alloc_coherent(&dcdbas_pdev->dev, size,
&smi_buffer->dma, GFP_KERNEL);
if (!smi_buffer->virt) {
dev_dbg(&dcdbas_pdev->dev,
"%s: failed to allocate memory size %lu\n",
__func__, size);
return -ENOMEM;
}
smi_buffer->size = size;
dev_dbg(&dcdbas_pdev->dev, "%s: phys: %x size: %lu\n",
__func__, (u32)smi_buffer->dma, smi_buffer->size);
return 0;
}
EXPORT_SYMBOL_GPL(dcdbas_smi_alloc);
void dcdbas_smi_free(struct smi_buffer *smi_buffer)
{
if (!smi_buffer->virt)
return;
dev_dbg(&dcdbas_pdev->dev, "%s: phys: %x size: %lu\n",
__func__, (u32)smi_buffer->dma, smi_buffer->size);
dma_free_coherent(&dcdbas_pdev->dev, smi_buffer->size,
smi_buffer->virt, smi_buffer->dma);
smi_buffer->virt = NULL;
smi_buffer->dma = 0;
smi_buffer->size = 0;
}
EXPORT_SYMBOL_GPL(dcdbas_smi_free);
/**
* smi_data_buf_free: free SMI data buffer
*/
static void smi_data_buf_free(void)
{
if (!smi_buf.virt || wsmt_enabled)
return;
dcdbas_smi_free(&smi_buf);
}
/**
* smi_data_buf_realloc: grow SMI data buffer if needed
*/
static int smi_data_buf_realloc(unsigned long size)
{
struct smi_buffer tmp;
int ret;
if (smi_buf.size >= size)
return 0;
if (size > max_smi_data_buf_size)
return -EINVAL;
/* new buffer is needed */
ret = dcdbas_smi_alloc(&tmp, size);
if (ret)
return ret;
/* memory zeroed by dma_alloc_coherent */
if (smi_buf.virt)
memcpy(tmp.virt, smi_buf.virt, smi_buf.size);
/* free any existing buffer */
smi_data_buf_free();
/* set up new buffer for use */
smi_buf = tmp;
return 0;
}
static ssize_t smi_data_buf_phys_addr_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
return sprintf(buf, "%x\n", (u32)smi_buf.dma);
}
static ssize_t smi_data_buf_size_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
return sprintf(buf, "%lu\n", smi_buf.size);
}
static ssize_t smi_data_buf_size_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
unsigned long buf_size;
ssize_t ret;
buf_size = simple_strtoul(buf, NULL, 10);
/* make sure SMI data buffer is at least buf_size */
mutex_lock(&smi_data_lock);
ret = smi_data_buf_realloc(buf_size);
mutex_unlock(&smi_data_lock);
if (ret)
return ret;
return count;
}
static ssize_t smi_data_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t pos, size_t count)
{
ssize_t ret;
mutex_lock(&smi_data_lock);
ret = memory_read_from_buffer(buf, count, &pos, smi_buf.virt,
smi_buf.size);
mutex_unlock(&smi_data_lock);
return ret;
}
static ssize_t smi_data_write(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t pos, size_t count)
{
ssize_t ret;
if ((pos + count) > max_smi_data_buf_size)
return -EINVAL;
mutex_lock(&smi_data_lock);
ret = smi_data_buf_realloc(pos + count);
if (ret)
goto out;
memcpy(smi_buf.virt + pos, buf, count);
ret = count;
out:
mutex_unlock(&smi_data_lock);
return ret;
}
static ssize_t host_control_action_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
return sprintf(buf, "%u\n", host_control_action);
}
static ssize_t host_control_action_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
ssize_t ret;
/* make sure buffer is available for host control command */
mutex_lock(&smi_data_lock);
ret = smi_data_buf_realloc(sizeof(struct apm_cmd));
mutex_unlock(&smi_data_lock);
if (ret)
return ret;
host_control_action = simple_strtoul(buf, NULL, 10);
return count;
}
static ssize_t host_control_smi_type_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
return sprintf(buf, "%u\n", host_control_smi_type);
}
static ssize_t host_control_smi_type_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
host_control_smi_type = simple_strtoul(buf, NULL, 10);
return count;
}
static ssize_t host_control_on_shutdown_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
return sprintf(buf, "%u\n", host_control_on_shutdown);
}
static ssize_t host_control_on_shutdown_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
host_control_on_shutdown = simple_strtoul(buf, NULL, 10);
return count;
}
static int raise_smi(void *par)
{
struct smi_cmd *smi_cmd = par;
if (smp_processor_id() != 0) {
dev_dbg(&dcdbas_pdev->dev, "%s: failed to get CPU 0\n",
__func__);
return -EBUSY;
}
/* generate SMI */
/* inb to force posted write through and make SMI happen now */
asm volatile (
"outb %b0,%w1\n"
"inb %w1"
: /* no output args */
: "a" (smi_cmd->command_code),
"d" (smi_cmd->command_address),
"b" (smi_cmd->ebx),
"c" (smi_cmd->ecx)
: "memory"
);
return 0;
}
/**
* dcdbas_smi_request: generate SMI request
*
* Called with smi_data_lock.
*/
int dcdbas_smi_request(struct smi_cmd *smi_cmd)
{
int ret;
if (smi_cmd->magic != SMI_CMD_MAGIC) {
dev_info(&dcdbas_pdev->dev, "%s: invalid magic value\n",
__func__);
return -EBADR;
}
/* SMI requires CPU 0 */
cpus_read_lock();
ret = smp_call_on_cpu(0, raise_smi, smi_cmd, true);
cpus_read_unlock();
return ret;
}
EXPORT_SYMBOL(dcdbas_smi_request);
/**
* smi_request_store:
*
* The valid values are:
* 0: zero SMI data buffer
* 1: generate calling interface SMI
* 2: generate raw SMI
*
* User application writes smi_cmd to smi_data before telling driver
* to generate SMI.
*/
static ssize_t smi_request_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct smi_cmd *smi_cmd;
unsigned long val = simple_strtoul(buf, NULL, 10);
ssize_t ret;
mutex_lock(&smi_data_lock);
if (smi_buf.size < sizeof(struct smi_cmd)) {
ret = -ENODEV;
goto out;
}
smi_cmd = (struct smi_cmd *)smi_buf.virt;
switch (val) {
case 2:
/* Raw SMI */
ret = dcdbas_smi_request(smi_cmd);
if (!ret)
ret = count;
break;
case 1:
/*
* Calling Interface SMI
*
* Provide physical address of command buffer field within
* the struct smi_cmd to BIOS.
*
* Because the address that smi_cmd (smi_buf.virt) points to
* will be from memremap() of a non-memory address if WSMT
* is present, we can't use virt_to_phys() on smi_cmd, so
* we have to use the physical address that was saved when
* the virtual address for smi_cmd was received.
*/
smi_cmd->ebx = (u32)smi_buf.dma +
offsetof(struct smi_cmd, command_buffer);
ret = dcdbas_smi_request(smi_cmd);
if (!ret)
ret = count;
break;
case 0:
memset(smi_buf.virt, 0, smi_buf.size);
ret = count;
break;
default:
ret = -EINVAL;
break;
}
out:
mutex_unlock(&smi_data_lock);
return ret;
}
/**
* host_control_smi: generate host control SMI
*
* Caller must set up the host control command in smi_buf.virt.
*/
static int host_control_smi(void)
{
struct apm_cmd *apm_cmd;
u8 *data;
unsigned long flags;
u32 num_ticks;
s8 cmd_status;
u8 index;
apm_cmd = (struct apm_cmd *)smi_buf.virt;
apm_cmd->status = ESM_STATUS_CMD_UNSUCCESSFUL;
switch (host_control_smi_type) {
case HC_SMITYPE_TYPE1:
spin_lock_irqsave(&rtc_lock, flags);
/* write SMI data buffer physical address */
data = (u8 *)&smi_buf.dma;
for (index = PE1300_CMOS_CMD_STRUCT_PTR;
index < (PE1300_CMOS_CMD_STRUCT_PTR + 4);
index++, data++) {
outb(index,
(CMOS_BASE_PORT + CMOS_PAGE2_INDEX_PORT_PIIX4));
outb(*data,
(CMOS_BASE_PORT + CMOS_PAGE2_DATA_PORT_PIIX4));
}
/* first set status to -1 as called by spec */
cmd_status = ESM_STATUS_CMD_UNSUCCESSFUL;
outb((u8) cmd_status, PCAT_APM_STATUS_PORT);
/* generate SMM call */
outb(ESM_APM_CMD, PCAT_APM_CONTROL_PORT);
spin_unlock_irqrestore(&rtc_lock, flags);
/* wait a few to see if it executed */
num_ticks = TIMEOUT_USEC_SHORT_SEMA_BLOCKING;
while ((s8)inb(PCAT_APM_STATUS_PORT) == ESM_STATUS_CMD_UNSUCCESSFUL) {
num_ticks--;
if (num_ticks == EXPIRED_TIMER)
return -ETIME;
}
break;
case HC_SMITYPE_TYPE2:
case HC_SMITYPE_TYPE3:
spin_lock_irqsave(&rtc_lock, flags);
/* write SMI data buffer physical address */
data = (u8 *)&smi_buf.dma;
for (index = PE1400_CMOS_CMD_STRUCT_PTR;
index < (PE1400_CMOS_CMD_STRUCT_PTR + 4);
index++, data++) {
outb(index, (CMOS_BASE_PORT + CMOS_PAGE1_INDEX_PORT));
outb(*data, (CMOS_BASE_PORT + CMOS_PAGE1_DATA_PORT));
}
/* generate SMM call */
if (host_control_smi_type == HC_SMITYPE_TYPE3)
outb(ESM_APM_CMD, PCAT_APM_CONTROL_PORT);
else
outb(ESM_APM_CMD, PE1400_APM_CONTROL_PORT);
/* restore RTC index pointer since it was written to above */
CMOS_READ(RTC_REG_C);
spin_unlock_irqrestore(&rtc_lock, flags);
/* read control port back to serialize write */
cmd_status = inb(PE1400_APM_CONTROL_PORT);
/* wait a few to see if it executed */
num_ticks = TIMEOUT_USEC_SHORT_SEMA_BLOCKING;
while (apm_cmd->status == ESM_STATUS_CMD_UNSUCCESSFUL) {
num_ticks--;
if (num_ticks == EXPIRED_TIMER)
return -ETIME;
}
break;
default:
dev_dbg(&dcdbas_pdev->dev, "%s: invalid SMI type %u\n",
__func__, host_control_smi_type);
return -ENOSYS;
}
return 0;
}
/**
* dcdbas_host_control: initiate host control
*
* This function is called by the driver after the system has
* finished shutting down if the user application specified a
* host control action to perform on shutdown. It is safe to
* use smi_buf.virt at this point because the system has finished
* shutting down and no userspace apps are running.
*/
static void dcdbas_host_control(void)
{
struct apm_cmd *apm_cmd;
u8 action;
if (host_control_action == HC_ACTION_NONE)
return;
action = host_control_action;
host_control_action = HC_ACTION_NONE;
if (!smi_buf.virt) {
dev_dbg(&dcdbas_pdev->dev, "%s: no SMI buffer\n", __func__);
return;
}
if (smi_buf.size < sizeof(struct apm_cmd)) {
dev_dbg(&dcdbas_pdev->dev, "%s: SMI buffer too small\n",
__func__);
return;
}
apm_cmd = (struct apm_cmd *)smi_buf.virt;
/* power off takes precedence */
if (action & HC_ACTION_HOST_CONTROL_POWEROFF) {
apm_cmd->command = ESM_APM_POWER_CYCLE;
apm_cmd->reserved = 0;
*((s16 *)&apm_cmd->parameters.shortreq.parm[0]) = (s16) 0;
host_control_smi();
} else if (action & HC_ACTION_HOST_CONTROL_POWERCYCLE) {
apm_cmd->command = ESM_APM_POWER_CYCLE;
apm_cmd->reserved = 0;
*((s16 *)&apm_cmd->parameters.shortreq.parm[0]) = (s16) 20;
host_control_smi();
}
}
/* WSMT */
static u8 checksum(u8 *buffer, u8 length)
{
u8 sum = 0;
u8 *end = buffer + length;
while (buffer < end)
sum += *buffer++;
return sum;
}
static inline struct smm_eps_table *check_eps_table(u8 *addr)
{
struct smm_eps_table *eps = (struct smm_eps_table *)addr;
if (strncmp(eps->smm_comm_buff_anchor, SMM_EPS_SIG, 4) != 0)
return NULL;
if (checksum(addr, eps->length) != 0)
return NULL;
return eps;
}
static int dcdbas_check_wsmt(void)
{
const struct dmi_device *dev = NULL;
struct acpi_table_wsmt *wsmt = NULL;
struct smm_eps_table *eps = NULL;
u64 bios_buf_paddr;
u64 remap_size;
u8 *addr;
acpi_get_table(ACPI_SIG_WSMT, 0, (struct acpi_table_header **)&wsmt);
if (!wsmt)
return 0;
/* Check if WSMT ACPI table shows that protection is enabled */
if (!(wsmt->protection_flags & ACPI_WSMT_FIXED_COMM_BUFFERS) ||
!(wsmt->protection_flags & ACPI_WSMT_COMM_BUFFER_NESTED_PTR_PROTECTION))
return 0;
/*
* BIOS could provide the address/size of the protected buffer
* in an SMBIOS string or in an EPS structure in 0xFxxxx.
*/
/* Check SMBIOS for buffer address */
while ((dev = dmi_find_device(DMI_DEV_TYPE_OEM_STRING, NULL, dev)))
if (sscanf(dev->name, "30[%16llx;%8llx]", &bios_buf_paddr,
&remap_size) == 2)
goto remap;
/* Scan for EPS (entry point structure) */
for (addr = (u8 *)__va(0xf0000);
addr < (u8 *)__va(0x100000 - sizeof(struct smm_eps_table));
addr += 16) {
eps = check_eps_table(addr);
if (eps)
break;
}
if (!eps) {
dev_dbg(&dcdbas_pdev->dev, "found WSMT, but no firmware buffer found\n");
return -ENODEV;
}
bios_buf_paddr = eps->smm_comm_buff_addr;
remap_size = eps->num_of_4k_pages * PAGE_SIZE;
remap:
/*
* Get physical address of buffer and map to virtual address.
* Table gives size in 4K pages, regardless of actual system page size.
*/
if (upper_32_bits(bios_buf_paddr + 8)) {
dev_warn(&dcdbas_pdev->dev, "found WSMT, but buffer address is above 4GB\n");
return -EINVAL;
}
/*
* Limit remap size to MAX_SMI_DATA_BUF_SIZE + 8 (since the first 8
* bytes are used for a semaphore, not the data buffer itself).
*/
if (remap_size > MAX_SMI_DATA_BUF_SIZE + 8)
remap_size = MAX_SMI_DATA_BUF_SIZE + 8;
bios_buffer = memremap(bios_buf_paddr, remap_size, MEMREMAP_WB);
if (!bios_buffer) {
dev_warn(&dcdbas_pdev->dev, "found WSMT, but failed to map buffer\n");
return -ENOMEM;
}
/* First 8 bytes is for a semaphore, not part of the smi_buf.virt */
smi_buf.dma = bios_buf_paddr + 8;
smi_buf.virt = bios_buffer + 8;
smi_buf.size = remap_size - 8;
max_smi_data_buf_size = smi_buf.size;
wsmt_enabled = true;
dev_info(&dcdbas_pdev->dev,
"WSMT found, using firmware-provided SMI buffer.\n");
return 1;
}
/**
* dcdbas_reboot_notify: handle reboot notification for host control
*/
static int dcdbas_reboot_notify(struct notifier_block *nb, unsigned long code,
void *unused)
{
switch (code) {
case SYS_DOWN:
case SYS_HALT:
case SYS_POWER_OFF:
if (host_control_on_shutdown) {
/* firmware is going to perform host control action */
printk(KERN_WARNING "Please wait for shutdown "
"action to complete...\n");
dcdbas_host_control();
}
break;
}
return NOTIFY_DONE;
}
static struct notifier_block dcdbas_reboot_nb = {
.notifier_call = dcdbas_reboot_notify,
.next = NULL,
.priority = INT_MIN
};
static DCDBAS_BIN_ATTR_RW(smi_data);
static struct bin_attribute *dcdbas_bin_attrs[] = {
&bin_attr_smi_data,
NULL
};
static DCDBAS_DEV_ATTR_RW(smi_data_buf_size);
static DCDBAS_DEV_ATTR_RO(smi_data_buf_phys_addr);
static DCDBAS_DEV_ATTR_WO(smi_request);
static DCDBAS_DEV_ATTR_RW(host_control_action);
static DCDBAS_DEV_ATTR_RW(host_control_smi_type);
static DCDBAS_DEV_ATTR_RW(host_control_on_shutdown);
static struct attribute *dcdbas_dev_attrs[] = {
&dev_attr_smi_data_buf_size.attr,
&dev_attr_smi_data_buf_phys_addr.attr,
&dev_attr_smi_request.attr,
&dev_attr_host_control_action.attr,
&dev_attr_host_control_smi_type.attr,
&dev_attr_host_control_on_shutdown.attr,
NULL
};
static const struct attribute_group dcdbas_attr_group = {
.attrs = dcdbas_dev_attrs,
.bin_attrs = dcdbas_bin_attrs,
};
static int dcdbas_probe(struct platform_device *dev)
{
int error;
host_control_action = HC_ACTION_NONE;
host_control_smi_type = HC_SMITYPE_NONE;
dcdbas_pdev = dev;
/* Check if ACPI WSMT table specifies protected SMI buffer address */
error = dcdbas_check_wsmt();
if (error < 0)
return error;
/*
* BIOS SMI calls require buffer addresses be in 32-bit address space.
* This is done by setting the DMA mask below.
*/
error = dma_set_coherent_mask(&dcdbas_pdev->dev, DMA_BIT_MASK(32));
if (error)
return error;
error = sysfs_create_group(&dev->dev.kobj, &dcdbas_attr_group);
if (error)
return error;
register_reboot_notifier(&dcdbas_reboot_nb);
dev_info(&dev->dev, "%s (version %s)\n",
DRIVER_DESCRIPTION, DRIVER_VERSION);
return 0;
}
static void dcdbas_remove(struct platform_device *dev)
{
unregister_reboot_notifier(&dcdbas_reboot_nb);
sysfs_remove_group(&dev->dev.kobj, &dcdbas_attr_group);
}
static struct platform_driver dcdbas_driver = {
.driver = {
.name = DRIVER_NAME,
},
.probe = dcdbas_probe,
.remove_new = dcdbas_remove,
};
static const struct platform_device_info dcdbas_dev_info __initconst = {
.name = DRIVER_NAME,
.id = PLATFORM_DEVID_NONE,
.dma_mask = DMA_BIT_MASK(32),
};
static struct platform_device *dcdbas_pdev_reg;
/**
* dcdbas_init: initialize driver
*/
static int __init dcdbas_init(void)
{
int error;
error = platform_driver_register(&dcdbas_driver);
if (error)
return error;
dcdbas_pdev_reg = platform_device_register_full(&dcdbas_dev_info);
if (IS_ERR(dcdbas_pdev_reg)) {
error = PTR_ERR(dcdbas_pdev_reg);
goto err_unregister_driver;
}
return 0;
err_unregister_driver:
platform_driver_unregister(&dcdbas_driver);
return error;
}
/**
* dcdbas_exit: perform driver cleanup
*/
static void __exit dcdbas_exit(void)
{
/*
* make sure functions that use dcdbas_pdev are called
* before platform_device_unregister
*/
unregister_reboot_notifier(&dcdbas_reboot_nb);
/*
* We have to free the buffer here instead of dcdbas_remove
* because only in module exit function we can be sure that
* all sysfs attributes belonging to this module have been
* released.
*/
if (dcdbas_pdev)
smi_data_buf_free();
if (bios_buffer)
memunmap(bios_buffer);
platform_device_unregister(dcdbas_pdev_reg);
platform_driver_unregister(&dcdbas_driver);
}
subsys_initcall_sync(dcdbas_init);
module_exit(dcdbas_exit);
MODULE_DESCRIPTION(DRIVER_DESCRIPTION " (version " DRIVER_VERSION ")");
MODULE_VERSION(DRIVER_VERSION);
MODULE_AUTHOR("Dell Inc.");
MODULE_LICENSE("GPL");
/* Any System or BIOS claiming to be by Dell */
MODULE_ALIAS("dmi:*:[bs]vnD[Ee][Ll][Ll]*:*");
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