e1000e: write protect ICHx NVM to prevent malicious write/erase

[safe/jmp/linux-2.6] / drivers / net / e1000e / ich8lan.c

diff --git a/drivers/net/e1000e/ich8lan.c b/drivers/net/e1000e/ich8lan.c
index 9e38452..d8efba8 100644 (file)
--- a/drivers/net/e1000e/ich8lan.c
+++ b/drivers/net/e1000e/ich8lan.c
@@ -58,6 +58,7 @@
 #define ICH_FLASH_HSFCTL               0x0006
 #define ICH_FLASH_FADDR                        0x0008
 #define ICH_FLASH_FDATA0               0x0010
+#define ICH_FLASH_PR0                  0x0074
 
 #define ICH_FLASH_READ_COMMAND_TIMEOUT 500
 #define ICH_FLASH_WRITE_COMMAND_TIMEOUT        500
@@ -150,6 +151,19 @@ union ich8_hws_flash_regacc {
        u16 regval;
 };
 
+/* ICH Flash Protected Region */
+union ich8_flash_protected_range {
+       struct ich8_pr {
+               u32 base:13;     /* 0:12 Protected Range Base */
+               u32 reserved1:2; /* 13:14 Reserved */
+               u32 rpe:1;       /* 15 Read Protection Enable */
+               u32 limit:13;    /* 16:28 Protected Range Limit */
+               u32 reserved2:2; /* 29:30 Reserved */
+               u32 wpe:1;       /* 31 Write Protection Enable */
+       } range;
+       u32 regval;
+};
+
 static s32 e1000_setup_link_ich8lan(struct e1000_hw *hw);
 static void e1000_clear_hw_cntrs_ich8lan(struct e1000_hw *hw);
 static void e1000_initialize_hw_bits_ich8lan(struct e1000_hw *hw);
@@ -1284,6 +1298,7 @@ static s32 e1000_update_nvm_checksum_ich8lan(struct e1000_hw *hw)
         * programming failed.
         */
        if (ret_val) {
+               /* Possibly read-only, see e1000e_write_protect_nvm_ich8lan() */
                hw_dbg(hw, "Flash commit failed.\n");
                e1000_release_swflag_ich8lan(hw);
                return ret_val;
@@ -1374,6 +1389,49 @@ static s32 e1000_validate_nvm_checksum_ich8lan(struct e1000_hw *hw)
 }
 
 /**
+ *  e1000e_write_protect_nvm_ich8lan - Make the NVM read-only
+ *  @hw: pointer to the HW structure
+ *
+ *  To prevent malicious write/erase of the NVM, set it to be read-only
+ *  so that the hardware ignores all write/erase cycles of the NVM via
+ *  the flash control registers.  The shadow-ram copy of the NVM will
+ *  still be updated, however any updates to this copy will not stick
+ *  across driver reloads.
+ **/
+void e1000e_write_protect_nvm_ich8lan(struct e1000_hw *hw)
+{
+       union ich8_flash_protected_range pr0;
+       union ich8_hws_flash_status hsfsts;
+       u32 gfpreg;
+       s32 ret_val;
+
+       ret_val = e1000_acquire_swflag_ich8lan(hw);
+       if (ret_val)
+               return;
+
+       gfpreg = er32flash(ICH_FLASH_GFPREG);
+
+       /* Write-protect GbE Sector of NVM */
+       pr0.regval = er32flash(ICH_FLASH_PR0);
+       pr0.range.base = gfpreg & FLASH_GFPREG_BASE_MASK;
+       pr0.range.limit = ((gfpreg >> 16) & FLASH_GFPREG_BASE_MASK);
+       pr0.range.wpe = true;
+       ew32flash(ICH_FLASH_PR0, pr0.regval);
+
+       /*
+        * Lock down a subset of GbE Flash Control Registers, e.g.
+        * PR0 to prevent the write-protection from being lifted.
+        * Once FLOCKDN is set, the registers protected by it cannot
+        * be written until FLOCKDN is cleared by a hardware reset.
+        */
+       hsfsts.regval = er16flash(ICH_FLASH_HSFSTS);
+       hsfsts.hsf_status.flockdn = true;
+       ew32flash(ICH_FLASH_HSFSTS, hsfsts.regval);
+
+       e1000_release_swflag_ich8lan(hw);
+}
+
+/**
  *  e1000_write_flash_data_ich8lan - Writes bytes to the NVM
  *  @hw: pointer to the HW structure
  *  @offset: The offset (in bytes) of the byte/word to read.