MdePkg/BaseLib: Support IA32 processors without CLFLUSH

[mirror_edk2.git] / MdePkg / Library / BaseLib / Ia32 / FlushCacheLine.c

diff --git a/MdePkg/Library/BaseLib/Ia32/FlushCacheLine.c b/MdePkg/Library/BaseLib/Ia32/FlushCacheLine.c
index d6fa2d39e4cbbc6766c6673035542b0be4d3a681..7ad12aba14cbbf07fb8d269ed3a4221b64bbe2be 100644 (file)
--- a/MdePkg/Library/BaseLib/Ia32/FlushCacheLine.c
+++ b/MdePkg/Library/BaseLib/Ia32/FlushCacheLine.c
@@ -1,20 +1,18 @@
 /** @file\r
   AsmFlushCacheLine function\r
 \r
-  Copyright (c) 2006 - 2007, Intel Corporation<BR>\r
-  All rights reserved. This program and the accompanying materials\r
+  Copyright (c) 2006 - 2015, Intel Corporation. All rights reserved.<BR>\r
+  This program and the accompanying materials\r
   are licensed and made available under the terms and conditions of the BSD License\r
   which accompanies this distribution.  The full text of the license may be found at\r
-  http://opensource.org/licenses/bsd-license.php\r
+  http://opensource.org/licenses/bsd-license.php.\r
 \r
   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
 \r
 **/\r
 \r
-//\r
-// Include common header file for this module.\r
-//\r
+\r
 \r
 \r
 /**\r
@@ -22,7 +20,7 @@
   coherency domain of the CPU.\r
 \r
   Flushed the cache line specified by LinearAddress, and returns LinearAddress.\r
-  This function is only available on IA-32 and X64.\r
+  This function is only available on IA-32 and x64.\r
 \r
   @param  LinearAddress The address of the cache line to flush. If the CPU is\r
                         in a physical addressing mode, then LinearAddress is a\r
@@ -38,9 +36,23 @@ AsmFlushCacheLine (
   IN      VOID                      *LinearAddress\r
   )\r
 {\r
+  //\r
+  // If the CPU does not support CLFLUSH instruction, \r
+  // then promote flush range to flush entire cache.\r
+  //\r
   _asm {\r
-    mov     eax, LinearAddress\r
+    mov     eax, 1\r
+    cpuid\r
+    test    edx, BIT19\r
+    jz      NoClflush\r
+    mov     eax, [esp + 4]\r
     clflush [eax]\r
+    jmp     Done\r
+NoClflush:\r
+    wbinvd\r
+Done:\r
   }\r
+  \r
+  return LinearAddress;\r
 }\r
 \r