Commit 47a94c55 authored by Stuart Hayes's avatar Stuart Hayes Committed by Andy Shevchenko
Browse files

platform/x86: dcdbas: Check SMBIOS for protected buffer address 



Add support for a new method for BIOS to provide the address and length
of the protected SMI communication buffer, via SMBIOS OEM strings.

Signed-off-by: default avatarStuart Hayes <stuart.w.hayes@gmail.com>
Signed-off-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
parent 30a44f7b

drivers/platform/x86/dcdbas.c

+30 −13
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ 
#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>
@@ -34,7 +35,7 @@ 
#include "dcdbas.h"



#define DRIVER_NAME		"dcdbas"

#define DRIVER_VERSION		"5.6.0-3.3"

#define DRIVER_VERSION		"5.6.0-3.4"

#define DRIVER_DESCRIPTION	"Dell Systems Management Base Driver"



static struct platform_device *dcdbas_pdev;
@@ -45,7 +46,7 @@ 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 u8 *bios_buffer;



static unsigned int host_control_action;

static unsigned int host_control_smi_type;
@@ -518,8 +519,10 @@ static inline struct smm_eps_table *check_eps_table(u8 *addr) 


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;
@@ -532,6 +535,17 @@ static int dcdbas_check_wsmt(void) 
	    !(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));
@@ -542,34 +556,37 @@ static int dcdbas_check_wsmt(void) 
	}



	if (!eps) {

		dev_dbg(&dcdbas_pdev->dev, "found WSMT, but no EPS found\n");

		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(eps->smm_comm_buff_addr + 8)) {

		dev_warn(&dcdbas_pdev->dev, "found WSMT, but EPS buffer address is above 4GB\n");

	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).

	 */

	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");



	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_data_buf */

	smi_data_buf_phys_addr = eps->smm_comm_buff_addr + 8;

	smi_data_buf = eps_buffer + 8;

	smi_data_buf_phys_addr = bios_buf_paddr + 8;

	smi_data_buf = bios_buffer + 8;

	smi_data_buf_size = remap_size - 8;

	max_smi_data_buf_size = smi_data_buf_size;

	wsmt_enabled = true;
@@ -736,8 +753,8 @@ static void __exit dcdbas_exit(void) 
	 */

	if (dcdbas_pdev)

		smi_data_buf_free();

	if (eps_buffer)

		memunmap(eps_buffer);

	if (bios_buffer)

		memunmap(bios_buffer);

	platform_device_unregister(dcdbas_pdev_reg);

	platform_driver_unregister(&dcdbas_driver);

}