1 files changed, 30 insertions, 2 deletions

diff --git a/drivers/char/hw_random/intel-rng.c b/drivers/char/hw_random/intel-rng.c
index 8efbc9c0e545..154ce3e6b3c9 100644
--- a/drivers/char/hw_random/intel-rng.c
+++ b/drivers/char/hw_random/intel-rng.c
@@ -143,6 +143,11 @@ static const struct pci_device_id pci_tbl[] = {
 };
 MODULE_DEVICE_TABLE(pci, pci_tbl);
 
+static __initdata int no_fwh_detect;
+module_param(no_fwh_detect, int, 0);
+MODULE_PARM_DESC(no_fwh_detect, "Skip FWH detection:\n"
+                                " positive value - skip if FWH space locked read-only\n"
+                                " negative value - skip always");
 
 static inline u8 hwstatus_get(void __iomem *mem)
 {
@@ -240,6 +245,11 @@ static int __init mod_init(void)
         if (!dev)
                 goto out; /* Device not found. */
 
+        if (no_fwh_detect < 0) {
+                pci_dev_put(dev);
+                goto fwh_done;
+        }
+
         /* Check for Intel 82802 */
         if (dev->device < 0x2640) {
                 fwh_dec_en1_off = FWH_DEC_EN1_REG_OLD;
@@ -252,6 +262,23 @@ static int __init mod_init(void)
         pci_read_config_byte(dev, fwh_dec_en1_off, &fwh_dec_en1_val);
         pci_read_config_byte(dev, bios_cntl_off, &bios_cntl_val);
 
+        if ((bios_cntl_val &
+             (BIOS_CNTL_LOCK_ENABLE_MASK|BIOS_CNTL_WRITE_ENABLE_MASK))
+            == BIOS_CNTL_LOCK_ENABLE_MASK) {
+                static __initdata /*const*/ char warning[] =
+                        KERN_WARNING PFX "Firmware space is locked read-only. If you can't or\n"
+                        KERN_WARNING PFX "don't want to disable this in firmware setup, and if\n"
+                        KERN_WARNING PFX "you are certain that your system has a functional\n"
+                        KERN_WARNING PFX "RNG, try using the 'no_fwh_detect' option.\n";
+
+                pci_dev_put(dev);
+                if (no_fwh_detect)
+                        goto fwh_done;
+                printk(warning);
+                err = -EBUSY;
+                goto out;
+        }
+
         mem = ioremap_nocache(INTEL_FWH_ADDR, INTEL_FWH_ADDR_LEN);
         if (mem == NULL) {
                 pci_dev_put(dev);
@@ -280,8 +307,7 @@ static int __init mod_init(void)
                 pci_write_config_byte(dev,
                                       fwh_dec_en1_off,
                                       fwh_dec_en1_val | FWH_F8_EN_MASK);
-        if (!(bios_cntl_val &
-              (BIOS_CNTL_LOCK_ENABLE_MASK|BIOS_CNTL_WRITE_ENABLE_MASK)))
+        if (!(bios_cntl_val & BIOS_CNTL_WRITE_ENABLE_MASK))
                 pci_write_config_byte(dev,
                                       bios_cntl_off,
                                       bios_cntl_val | BIOS_CNTL_WRITE_ENABLE_MASK);
@@ -315,6 +341,8 @@ static int __init mod_init(void)
                 goto out;
         }
 
+fwh_done:
+
         err = -ENOMEM;
         mem = ioremap(INTEL_RNG_ADDR, INTEL_RNG_ADDR_LEN);
         if (!mem)