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author | raywu <raywu0301@gmail.com> | 2018-06-15 00:00:50 +0800 |
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committer | raywu <raywu0301@gmail.com> | 2018-06-15 00:00:50 +0800 |
commit | b7c51c9cf4864df6aabb99a1ae843becd577237c (patch) | |
tree | eebe9b0d0ca03062955223097e57da84dd618b9a /EDK/Foundation/Library/RuntimeDxe/EfiRuntimeLib/ia32/Lock.c | |
download | zprj-master.tar.xz |
Diffstat (limited to 'EDK/Foundation/Library/RuntimeDxe/EfiRuntimeLib/ia32/Lock.c')
-rw-r--r-- | EDK/Foundation/Library/RuntimeDxe/EfiRuntimeLib/ia32/Lock.c | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/EDK/Foundation/Library/RuntimeDxe/EfiRuntimeLib/ia32/Lock.c b/EDK/Foundation/Library/RuntimeDxe/EfiRuntimeLib/ia32/Lock.c new file mode 100644 index 0000000..596da27 --- /dev/null +++ b/EDK/Foundation/Library/RuntimeDxe/EfiRuntimeLib/ia32/Lock.c @@ -0,0 +1,177 @@ +/*++ + +Copyright (c) 2004, Intel Corporation +All rights reserved. This program and the accompanying materials +are licensed and made available under the terms and conditions of the BSD License +which accompanies this distribution. The full text of the license may be found at +http://opensource.org/licenses/bsd-license.php + +THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, +WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. + +Module Name: + + Lock.c + +Abstract: + + Support for locking lib services. + +--*/ + +#include "Tiano.h" +#include "EfiDriverLib.h" + +extern +BOOLEAN +EfiAtRuntime ( + VOID + ); + +VOID +EfiInitializeLock ( + IN OUT EFI_LOCK *Lock, + IN EFI_TPL Priority + ) +/*++ + +Routine Description: + + Initialize a basic mutual exclusion lock. Each lock + provides mutual exclusion access at it's task priority + level. Since there is no-premption (at any TPL) or + multiprocessor support, acquiring the lock only consists + of raising to the locks TPL. + + Note on a check build ASSERT()s are used to ensure proper + lock usage. + +Arguments: + + Lock - The EFI_LOCK structure to initialize + + Priority - The task priority level of the lock + + +Returns: + + An initialized Efi Lock structure. + +--*/ +{ + Lock->Tpl = Priority; + Lock->OwnerTpl = 0; + Lock->Lock = 0; +} + +EFI_STATUS +EfiAcquireLockOrFail ( + IN EFI_LOCK *Lock + ) +/*++ + +Routine Description: + + Initialize a basic mutual exclusion lock. Each lock + provides mutual exclusion access at it's task priority + level. Since there is no-premption (at any TPL) or + multiprocessor support, acquiring the lock only consists + of raising to the locks TPL. + +Arguments: + + Lock - The EFI_LOCK structure to initialize + +Returns: + + EFI_SUCCESS - Lock Owned. + EFI_ACCESS_DENIED - Reentrant Lock Acquisition, Lock not Owned. + +--*/ +{ + if (Lock->Lock != 0) { + // + // Lock is already owned, so bail out + // + return EFI_ACCESS_DENIED; + } + + if (!EfiAtRuntime ()) { + // + // The check is just debug code for core inplementation. It must + // always be true in a driver + // + Lock->OwnerTpl = gBS->RaiseTPL (Lock->Tpl); + } + + Lock->Lock += 1; + return EFI_SUCCESS; +} + +VOID +EfiAcquireLock ( + IN EFI_LOCK *Lock + ) +/*++ + +Routine Description: + + Raising to the task priority level of the mutual exclusion + lock, and then acquires ownership of the lock. + +Arguments: + + Lock - The lock to acquire + +Returns: + + Lock owned + +--*/ +{ + EFI_STATUS Status; + + Status = EfiAcquireLockOrFail (Lock); + + // + // Lock was already locked. + // + ASSERT_EFI_ERROR (Status); +} + +VOID +EfiReleaseLock ( + IN EFI_LOCK *Lock + ) +/*++ + +Routine Description: + + Releases ownership of the mutual exclusion lock, and + restores the previous task priority level. + +Arguments: + + Lock - The lock to release + +Returns: + + Lock unowned + +--*/ +{ + EFI_TPL Tpl; + + Tpl = Lock->OwnerTpl; + + ASSERT (Lock->Lock == 1); + Lock->Lock -= 1; + + if (!EfiAtRuntime ()) { + // + // The check is just debug code for core inplementation. It must + // always be true in a driver + // + gBS->RestoreTPL (Tpl); + } +} |