MdePkg/BaseSynchronizationLib: Added proper support for ARM architecture
This implements the following synchronization primitives for AArch64 (GCC) and ARM (GCC & RVCT): InternalSyncCompareExchange32 InternalSyncCompareExchange64 InternalSyncIncrement InternalSyncDecrement Note: these functions are implemented using the exclusive monitor, which implies that they can only be used after the caches (and hence the MMU) have been enabled. Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Olivier Martin <olivier.martin@arm.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Laszlo Ersek <lersek@redhat.com> git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16965 6f19259b-4bc3-4df7-8a09-765794883524
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159
MdePkg/Library/BaseSynchronizationLib/AArch64/Synchronization.S
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159
MdePkg/Library/BaseSynchronizationLib/AArch64/Synchronization.S
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// Implementation of synchronization functions for ARM architecture (AArch64)
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//
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// Copyright (c) 2012-2015, ARM Limited. All rights reserved.
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// Copyright (c) 2015, Linaro Limited. All rights reserved.
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//
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// This program and the accompanying materials
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// are licensed and made available under the terms and conditions of the BSD License
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// which accompanies this distribution. The full text of the license may be found at
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// http://opensource.org/licenses/bsd-license.php
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//
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// THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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// WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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//
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//
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.text
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.align 3
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GCC_ASM_EXPORT(InternalSyncCompareExchange32)
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GCC_ASM_EXPORT(InternalSyncCompareExchange64)
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GCC_ASM_EXPORT(InternalSyncIncrement)
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GCC_ASM_EXPORT(InternalSyncDecrement)
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/**
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Performs an atomic compare exchange operation on a 32-bit unsigned integer.
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Performs an atomic compare exchange operation on the 32-bit unsigned integer
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specified by Value. If Value is equal to CompareValue, then Value is set to
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ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue,
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then Value is returned. The compare exchange operation must be performed using
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MP safe mechanisms.
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@param Value A pointer to the 32-bit value for the compare exchange
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operation.
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@param CompareValue 32-bit value used in compare operation.
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@param ExchangeValue 32-bit value used in exchange operation.
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@return The original *Value before exchange.
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**/
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//UINT32
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//EFIAPI
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//InternalSyncCompareExchange32 (
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// IN volatile UINT32 *Value,
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// IN UINT32 CompareValue,
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// IN UINT32 ExchangeValue
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// )
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ASM_PFX(InternalSyncCompareExchange32):
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dmb sy
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InternalSyncCompareExchange32Again:
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ldxr w3, [x0]
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cmp w3, w1
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bne InternalSyncCompareExchange32Fail
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InternalSyncCompareExchange32Exchange:
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stxr w4, w2, [x0]
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cbnz w4, InternalSyncCompareExchange32Again
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InternalSyncCompareExchange32Fail:
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dmb sy
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mov w0, w3
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ret
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/**
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Performs an atomic compare exchange operation on a 64-bit unsigned integer.
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Performs an atomic compare exchange operation on the 64-bit unsigned integer specified
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by Value. If Value is equal to CompareValue, then Value is set to ExchangeValue and
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CompareValue is returned. If Value is not equal to CompareValue, then Value is returned.
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The compare exchange operation must be performed using MP safe mechanisms.
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@param Value A pointer to the 64-bit value for the compare exchange
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operation.
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@param CompareValue 64-bit value used in compare operation.
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@param ExchangeValue 64-bit value used in exchange operation.
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@return The original *Value before exchange.
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**/
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//UINT64
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//EFIAPI
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//InternalSyncCompareExchange64 (
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// IN volatile UINT64 *Value,
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// IN UINT64 CompareValue,
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// IN UINT64 ExchangeValue
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// )
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ASM_PFX(InternalSyncCompareExchange64):
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dmb sy
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InternalSyncCompareExchange64Again:
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ldxr x3, [x0]
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cmp x3, x1
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bne InternalSyncCompareExchange64Fail
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InternalSyncCompareExchange64Exchange:
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stxr w4, x2, [x0]
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cbnz w4, InternalSyncCompareExchange64Again
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InternalSyncCompareExchange64Fail:
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dmb sy
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mov x0, x3
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ret
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/**
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Performs an atomic increment of an 32-bit unsigned integer.
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Performs an atomic increment of the 32-bit unsigned integer specified by
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Value and returns the incremented value. The increment operation must be
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performed using MP safe mechanisms. The state of the return value is not
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guaranteed to be MP safe.
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@param Value A pointer to the 32-bit value to increment.
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@return The incremented value.
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**/
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//UINT32
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//EFIAPI
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//InternalSyncIncrement (
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// IN volatile UINT32 *Value
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// )
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ASM_PFX(InternalSyncIncrement):
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dmb sy
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TryInternalSyncIncrement:
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ldxr w1, [x0]
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add w1, w1, #1
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stxr w2, w1, [x0]
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cbnz w2, TryInternalSyncIncrement
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dmb sy
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ret
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/**
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Performs an atomic decrement of an 32-bit unsigned integer.
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Performs an atomic decrement of the 32-bit unsigned integer specified by
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Value and returns the decrement value. The decrement operation must be
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performed using MP safe mechanisms. The state of the return value is not
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guaranteed to be MP safe.
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@param Value A pointer to the 32-bit value to decrement.
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@return The decrement value.
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**/
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//UINT32
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//EFIAPI
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//InternalSyncDecrement (
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// IN volatile UINT32 *Value
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// )
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ASM_PFX(InternalSyncDecrement):
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dmb sy
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TryInternalSyncDecrement:
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ldxr w1, [x0]
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sub w1, w1, #1
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stxr w2, w1, [x0]
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cbnz w2, TryInternalSyncDecrement
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dmb sy
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ret
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