*/
#include <linux/platform_device.h>
+#include <linux/acpi.h>
#include <linux/dma-mapping.h>
#include <linux/errno.h>
#include <linux/cpu.h>
#include "dcdbas.h"
#define DRIVER_NAME "dcdbas"
-#define DRIVER_VERSION "5.6.0-3.2"
+#define DRIVER_VERSION "5.6.0-3.3"
#define DRIVER_DESCRIPTION "Dell Systems Management Base Driver"
static struct platform_device *dcdbas_pdev;
static u8 *smi_data_buf;
static dma_addr_t smi_data_buf_handle;
static unsigned long smi_data_buf_size;
+static unsigned long max_smi_data_buf_size = MAX_SMI_DATA_BUF_SIZE;
static u32 smi_data_buf_phys_addr;
static DEFINE_MUTEX(smi_data_lock);
+static u8 *eps_buffer;
static unsigned int host_control_action;
static unsigned int host_control_smi_type;
static unsigned int host_control_on_shutdown;
+static bool wsmt_enabled;
+
/**
* smi_data_buf_free: free SMI data buffer
*/
static void smi_data_buf_free(void)
{
- if (!smi_data_buf)
+ if (!smi_data_buf || wsmt_enabled)
return;
dev_dbg(&dcdbas_pdev->dev, "%s: phys: %x size: %lu\n",
if (smi_data_buf_size >= size)
return 0;
- if (size > MAX_SMI_DATA_BUF_SIZE)
+ if (size > max_smi_data_buf_size)
return -EINVAL;
/* new buffer is needed */
{
ssize_t ret;
- if ((pos + count) > MAX_SMI_DATA_BUF_SIZE)
+ if ((pos + count) > max_smi_data_buf_size)
return -EINVAL;
mutex_lock(&smi_data_lock);
ret = count;
break;
case 1:
- /* Calling Interface SMI */
- smi_cmd->ebx = (u32) virt_to_phys(smi_cmd->command_buffer);
+ /*
+ * Calling Interface SMI
+ *
+ * Provide physical address of command buffer field within
+ * the struct smi_cmd to BIOS.
+ *
+ * Because the address that smi_cmd (smi_data_buf) 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 = smi_data_buf_phys_addr +
+ offsetof(struct smi_cmd, command_buffer);
ret = dcdbas_smi_request(smi_cmd);
if (!ret)
ret = count;
}
}
+/* 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)
+{
+ struct acpi_table_wsmt *wsmt = NULL;
+ struct smm_eps_table *eps = NULL;
+ 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;
+
+ /* 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 EPS found\n");
+ return -ENODEV;
+ }
+
+ /*
+ * 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(eps->smm_comm_buff_addr + 8)) {
+ dev_warn(&dcdbas_pdev->dev, "found WSMT, but EPS 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).
+ */
+ remap_size = eps->num_of_4k_pages * PAGE_SIZE;
+ if (remap_size > MAX_SMI_DATA_BUF_SIZE + 8)
+ remap_size = MAX_SMI_DATA_BUF_SIZE + 8;
+ eps_buffer = memremap(eps->smm_comm_buff_addr, remap_size, MEMREMAP_WB);
+ if (!eps_buffer) {
+ dev_warn(&dcdbas_pdev->dev, "found WSMT, but failed to map EPS buffer\n");
+ return -ENOMEM;
+ }
+
+ /* First 8 bytes is for a semaphore, not part of the smi_data_buf */
+ smi_data_buf_phys_addr = eps->smm_comm_buff_addr + 8;
+ smi_data_buf = eps_buffer + 8;
+ smi_data_buf_size = remap_size - 8;
+ max_smi_data_buf_size = smi_data_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
*/
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.
*/
if (dcdbas_pdev)
smi_data_buf_free();
+ if (eps_buffer)
+ memunmap(eps_buffer);
platform_device_unregister(dcdbas_pdev_reg);
platform_driver_unregister(&dcdbas_driver);
}