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: Stuart Hayes <stuart.w.hayes@xxxxxxxxx>
---
drivers/platform/x86/dcdbas.c | 43 ++++++++++++++++++++++++-----------
1 file changed, 30 insertions(+), 13 deletions(-)
diff --git a/drivers/platform/x86/dcdbas.c b/drivers/platform/x86/dcdbas.c
index 84f4cc839cc3..d513a59a5d47 100644
--- a/drivers/platform/x86/dcdbas.c
+++ b/drivers/platform/x86/dcdbas.c
@@ -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);
}
--
2.18.1
