MdePkg/BaseLib: Support IA32 processors without CLFLUSH
[mirror_edk2.git] / MdePkg / Library / BaseLib / Ia32 / FlushCacheLine.c
1 /** @file
2 AsmFlushCacheLine function
3
4 Copyright (c) 2006 - 2015, Intel Corporation. All rights reserved.<BR>
5 This program and the accompanying materials
6 are licensed and made available under the terms and conditions of the BSD License
7 which accompanies this distribution. The full text of the license may be found at
8 http://opensource.org/licenses/bsd-license.php.
9
10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
12
13 **/
14
15
16
17
18 /**
19 Flushes a cache line from all the instruction and data caches within the
20 coherency domain of the CPU.
21
22 Flushed the cache line specified by LinearAddress, and returns LinearAddress.
23 This function is only available on IA-32 and x64.
24
25 @param LinearAddress The address of the cache line to flush. If the CPU is
26 in a physical addressing mode, then LinearAddress is a
27 physical address. If the CPU is in a virtual
28 addressing mode, then LinearAddress is a virtual
29 address.
30
31 @return LinearAddress
32 **/
33 VOID *
34 EFIAPI
35 AsmFlushCacheLine (
36 IN VOID *LinearAddress
37 )
38 {
39 //
40 // If the CPU does not support CLFLUSH instruction,
41 // then promote flush range to flush entire cache.
42 //
43 _asm {
44 mov eax, 1
45 cpuid
46 test edx, BIT19
47 jz NoClflush
48 mov eax, [esp + 4]
49 clflush [eax]
50 jmp Done
51 NoClflush:
52 wbinvd
53 Done:
54 }
55
56 return LinearAddress;
57 }
58