Ovmf/Xen: port XenBusDxe to other architectures

This patch updates XenBusDxe to use the 16-bit compare and exchange
function that was introduced for this purpose to the
BaseSynchronizationLib. It also provides a new generic implementation
of TestAndClearBit () using the same 16-bit compare and exchange, making
this module fully architecture agnostic.

Contributed-under: TianoCore Contribution Agreement 1.0
Reviewed-by: Anthony PERARD <anthony.perard@citrix.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@16975 6f19259b-4bc3-4df7-8a09-765794883524

10 files changed, 49 insertions, 197 deletions

diff --git a/OvmfPkg/XenBusDxe/GrantTable.c b/OvmfPkg/XenBusDxe/GrantTable.c
index 19117fbe03..6e47483f13 100644
--- a/OvmfPkg/XenBusDxe/GrantTable.c
+++ b/OvmfPkg/XenBusDxe/GrantTable.c
@@ -35,9 +35,9 @@
 #include <IndustryStandard/Xen/memory.h>

 

 #include <Library/XenHypercallLib.h>

+#include <Library/SynchronizationLib.h>

 

 #include "GrantTable.h"

-#include "InterlockedCompareExchange16.h"

 

 #define NR_RESERVED_ENTRIES 8

 

diff --git a/OvmfPkg/XenBusDxe/Ia32/InterlockedCompareExchange16.nasm b/OvmfPkg/XenBusDxe/Ia32/InterlockedCompareExchange16.nasm
deleted file mode 100644
index d45582dd81..0000000000
--- a/OvmfPkg/XenBusDxe/Ia32/InterlockedCompareExchange16.nasm
+++ /dev/null
@@ -1,42 +0,0 @@
-;------------------------------------------------------------------------------

-;

-; Copyright (c) 2006, Intel Corporation. All rights reserved.<BR>

-; 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:

-;

-;   InterlockedCompareExchange16.Asm

-;

-; Abstract:

-;

-;   InterlockedCompareExchange16 function

-;

-; Notes:

-;

-;------------------------------------------------------------------------------

-

-    SECTION .text

-

-;------------------------------------------------------------------------------

-; UINT32

-; EFIAPI

-; InternalSyncCompareExchange16 (

-;   IN      UINT16                    *Value,

-;   IN      UINT16                    CompareValue,

-;   IN      UINT16                    ExchangeValue

-;   );

-;------------------------------------------------------------------------------

-global ASM_PFX(InternalSyncCompareExchange16)

-ASM_PFX(InternalSyncCompareExchange16):

-    mov     ecx, [esp + 4]

-    mov     eax, [esp + 8]

-    mov     edx, [esp + 12]

-    lock    cmpxchg [ecx], dx

-    ret

-

diff --git a/OvmfPkg/XenBusDxe/Ia32/TestAndClearBit.nasm b/OvmfPkg/XenBusDxe/Ia32/TestAndClearBit.nasm
deleted file mode 100644
index d77f74ef24..0000000000
--- a/OvmfPkg/XenBusDxe/Ia32/TestAndClearBit.nasm
+++ /dev/null
@@ -1,16 +0,0 @@
-SECTION .text

-

-; INT32

-; EFIAPI

-; TestAndClearBit (

-;   IN  INT32 Bit,

-;   IN  volatile VOID* Address

-;   );

-global ASM_PFX(TestAndClearBit)

-ASM_PFX(TestAndClearBit):

-  mov ecx, [esp + 4]

-  mov edx, [esp + 8]

-  lock btr [edx], ecx

-  sbb eax, eax

-  ret

-

diff --git a/OvmfPkg/XenBusDxe/InterlockedCompareExchange16.c b/OvmfPkg/XenBusDxe/InterlockedCompareExchange16.c
deleted file mode 100644
index 2b0fadd88d..0000000000
--- a/OvmfPkg/XenBusDxe/InterlockedCompareExchange16.c
+++ /dev/null
@@ -1,33 +0,0 @@
-#include <Library/DebugLib.h>

-#include "InterlockedCompareExchange16.h"

-

-/**

-  Performs an atomic compare exchange operation on a 16-bit unsigned integer.

-

-  Performs an atomic compare exchange operation on the 16-bit unsigned integer

-  specified by Value.  If Value is equal to CompareValue, then Value is set to

-  ExchangeValue and CompareValue is returned.  If Value is not equal to CompareValue,

-  then Value is returned.  The compare exchange operation must be performed using

-  MP safe mechanisms.

-

-  If Value is NULL, then ASSERT().

-

-  @param  Value         A pointer to the 16-bit value for the compare exchange

-                        operation.

-  @param  CompareValue  16-bit value used in compare operation.

-  @param  ExchangeValue 16-bit value used in exchange operation.

-

-  @return The original *Value before exchange.

-

-**/

-UINT16

-EFIAPI

-InterlockedCompareExchange16 (

-  IN OUT  UINT16                    *Value,

-  IN      UINT16                    CompareValue,

-  IN      UINT16                    ExchangeValue

-  )

-{

-  ASSERT (Value != NULL);

-  return InternalSyncCompareExchange16 (Value, CompareValue, ExchangeValue);

-}

diff --git a/OvmfPkg/XenBusDxe/InterlockedCompareExchange16.h b/OvmfPkg/XenBusDxe/InterlockedCompareExchange16.h
deleted file mode 100644
index fd3f15b1c8..0000000000
--- a/OvmfPkg/XenBusDxe/InterlockedCompareExchange16.h
+++ /dev/null
@@ -1,38 +0,0 @@
-/**

-  Assembly implementation of InterlockedCompareExchange16.

-

-  Look at the documentation of InterlockedCompareExchange16.

-**/

-UINT16

-EFIAPI

-InternalSyncCompareExchange16 (

-  IN      volatile UINT16           *Value,

-  IN      UINT16                    CompareValue,

-  IN      UINT16                    ExchangeValue

-  );

-

-/**

-  Performs an atomic compare exchange operation on a 16-bit unsigned integer.

-

-  Performs an atomic compare exchange operation on the 16-bit unsigned integer

-  specified by Value.  If Value is equal to CompareValue, then Value is set to

-  ExchangeValue and CompareValue is returned.  If Value is not equal to CompareValue,

-  then Value is returned.  The compare exchange operation must be performed using

-  MP safe mechanisms.

-

-  If Value is NULL, then ASSERT().

-

-  @param  Value         A pointer to the 16-bit value for the compare exchange

-                        operation.

-  @param  CompareValue  16-bit value used in compare operation.

-  @param  ExchangeValue 16-bit value used in exchange operation.

-

-  @return The original *Value before exchange.

-**/

-UINT16

-EFIAPI

-InterlockedCompareExchange16 (

-  IN OUT  UINT16                    *Value,

-  IN      UINT16                    CompareValue,

-  IN      UINT16                    ExchangeValue

-  );

diff --git a/OvmfPkg/XenBusDxe/TestAndClearBit.c b/OvmfPkg/XenBusDxe/TestAndClearBit.c
new file mode 100644
index 0000000000..410677ee8a
--- /dev/null
+++ b/OvmfPkg/XenBusDxe/TestAndClearBit.c
@@ -0,0 +1,45 @@
+/** @file

+  Implementation of TestAndClearBit using compare-exchange primitive

+

+  Copyright (C) 2015, Linaro Ltd.

+

+  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.

+

+**/

+

+#include <Base.h>

+#include <Library/SynchronizationLib.h>

+

+INT32

+EFIAPI

+TestAndClearBit (

+  IN INT32            Bit,

+  IN VOID             *Address

+  )

+{

+  UINT16    Word, Read;

+  UINT16    Mask;

+

+  //

+  // Calculate the effective address relative to 'Address' based on the

+  // higher order bits of 'Bit'. Use signed shift instead of division to

+  // ensure we round towards -Inf, and end up with a positive shift in

+  // 'Bit', even if 'Bit' itself is negative.

+  //

+  Address += (Bit >> 4) * sizeof(UINT16);

+  Mask = 1U << (Bit & 15);

+

+  for (Word = *(UINT16 *) Address; Word & Mask; Word = Read) {

+    Read = InterlockedCompareExchange16 (Address, Word, Word & ~Mask);

+    if (Read == Word) {

+      return 1;

+    }

+  }

+  return 0;

+}

diff --git a/OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.nasm b/OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.nasm
deleted file mode 100644
index 048d1f32f6..0000000000
--- a/OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.nasm
+++ /dev/null
@@ -1,41 +0,0 @@
-;------------------------------------------------------------------------------

-;

-; Copyright (c) 2006, Intel Corporation. All rights reserved.<BR>

-; 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:

-;

-;   InterlockedCompareExchange16.Asm

-;

-; Abstract:

-;

-;   InterlockedCompareExchange16 function

-;

-; Notes:

-;

-;------------------------------------------------------------------------------

-

-    DEFAULT REL

-    SECTION .text

-

-;------------------------------------------------------------------------------

-; UINT16

-; EFIAPI

-; InterlockedCompareExchange16 (

-;   IN      UINT16                    *Value,

-;   IN      UINT16                    CompareValue,

-;   IN      UINT16                    ExchangeValue

-;   );

-;------------------------------------------------------------------------------

-global ASM_PFX(InternalSyncCompareExchange16)

-ASM_PFX(InternalSyncCompareExchange16):

-    mov     eax, edx

-    lock    cmpxchg [rcx], r8w

-    ret

-

diff --git a/OvmfPkg/XenBusDxe/X64/TestAndClearBit.nasm b/OvmfPkg/XenBusDxe/X64/TestAndClearBit.nasm
deleted file mode 100644
index a4859a62a2..0000000000
--- a/OvmfPkg/XenBusDxe/X64/TestAndClearBit.nasm
+++ /dev/null
@@ -1,15 +0,0 @@
-DEFAULT REL

-SECTION .text

-

-; INT32

-; EFIAPI

-; TestAndClearBit (

-;   IN  INT32 Bit,                // rcx

-;   IN  volatile VOID* Address    // rdx

-;   );

-global ASM_PFX(TestAndClearBit)

-ASM_PFX(TestAndClearBit):

-  lock btr [rdx], ecx

-  sbb eax, eax

-  ret

-

diff --git a/OvmfPkg/XenBusDxe/XenBusDxe.h b/OvmfPkg/XenBusDxe/XenBusDxe.h
index 6c306e017b..953e4b72e8 100644
--- a/OvmfPkg/XenBusDxe/XenBusDxe.h
+++ b/OvmfPkg/XenBusDxe/XenBusDxe.h
@@ -122,7 +122,7 @@ INT32
 EFIAPI

 TestAndClearBit (

   IN INT32 Bit,

-  IN volatile VOID *Address

+  IN VOID  *Address

   );

 

 CHAR8*

diff --git a/OvmfPkg/XenBusDxe/XenBusDxe.inf b/OvmfPkg/XenBusDxe/XenBusDxe.inf
index 31553ac5a6..f0c5db98b1 100644
--- a/OvmfPkg/XenBusDxe/XenBusDxe.inf
+++ b/OvmfPkg/XenBusDxe/XenBusDxe.inf
@@ -34,8 +34,6 @@
   DriverBinding.h

   ComponentName.c

   ComponentName.h

-  InterlockedCompareExchange16.c

-  InterlockedCompareExchange16.h

   GrantTable.c

   GrantTable.h

   EventChannel.c

@@ -45,14 +43,7 @@
   XenBus.c

   XenBus.h

   Helpers.c

-

-[Sources.IA32]

-  Ia32/InterlockedCompareExchange16.nasm

-  Ia32/TestAndClearBit.nasm

-

-[Sources.X64]

-  X64/InterlockedCompareExchange16.nasm

-  X64/TestAndClearBit.nasm

+  TestAndClearBit.c

 

 [LibraryClasses]

   UefiDriverEntryPoint

@@ -64,6 +55,7 @@
   DevicePathLib

   DebugLib

   XenHypercallLib

+  SynchronizationLib

 

 [Protocols]

   gEfiDriverBindingProtocolGuid