Re: [PATCH v2 07/18] OvmfPkg/XenBusDxe: Add InterlockedCompareExchange16.

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Thu, Sep 04, 2014 at 05:51:02PM +0100, Anthony PERARD wrote:
> This is a copy of InterlockedCompareExchange32 from the
> BaseSynchronizationLib.
> 
> The function will be used in the next patch.

Please spell out the name of it. Such as:

in the "OvmfPkg/XenBusDxe: Add Grant Table functions" patch.

> 
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
> 
> ---
> Change in V2:
> - Add intel compilation code
>   MSFT code is not compied over because I don't know how it works.

Not sure I understand that sentence. Which is the 'MSFT' code? The 'c'
or the assembler? Or is s/compied/copied/ ?


> ---
>  OvmfPkg/XenBusDxe/InterlockedCompareExchange16.h   | 15 ++++++++
>  .../XenBusDxe/InterlockedCompareExchange16Intel.c  | 32 +++++++++++++++++
>  .../XenBusDxe/X64/InterlockedCompareExchange16.asm | 41 ++++++++++++++++++++++
>  .../XenBusDxe/X64/InterlockedCompareExchange16.c   | 41 ++++++++++++++++++++++
>  OvmfPkg/XenBusDxe/XenBusDxe.inf                    |  4 +++
>  5 files changed, 133 insertions(+)
>  create mode 100644 OvmfPkg/XenBusDxe/InterlockedCompareExchange16.h
>  create mode 100644 OvmfPkg/XenBusDxe/InterlockedCompareExchange16Intel.c
>  create mode 100644 OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.asm
>  create mode 100644 OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.c
> 
> diff --git a/OvmfPkg/XenBusDxe/InterlockedCompareExchange16.h b/OvmfPkg/XenBusDxe/InterlockedCompareExchange16.h
> new file mode 100644
> index 0000000..9067882
> --- /dev/null
> +++ b/OvmfPkg/XenBusDxe/InterlockedCompareExchange16.h
> @@ -0,0 +1,15 @@
> +UINT16
> +EFIAPI
> +InternalSyncCompareExchange16 (
> +  IN      UINT16                    *Value,
> +  IN      UINT16                    CompareValue,
> +  IN      UINT16                    ExchangeValue
> +  );
> +
> +UINT16
> +EFIAPI
> +InterlockedCompareExchange16 (
> +  IN OUT volatile  UINT16           *Value,
> +  IN      UINT16                    CompareValue,
> +  IN      UINT16                    ExchangeValue
> +  );
> diff --git a/OvmfPkg/XenBusDxe/InterlockedCompareExchange16Intel.c b/OvmfPkg/XenBusDxe/InterlockedCompareExchange16Intel.c
> new file mode 100644
> index 0000000..bb40e70
> --- /dev/null
> +++ b/OvmfPkg/XenBusDxe/InterlockedCompareExchange16Intel.c
> @@ -0,0 +1,32 @@
> +#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/X64/InterlockedCompareExchange16.asm b/OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.asm
> new file mode 100644
> index 0000000..b23e421
> --- /dev/null
> +++ b/OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.asm
> @@ -0,0 +1,41 @@
> +;------------------------------------------------------------------------------
> +;
> +; 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:
> +;
> +;------------------------------------------------------------------------------
> +
> +    .code
> +
> +;------------------------------------------------------------------------------
> +; UINT16
> +; EFIAPI
> +; InterlockedCompareExchange16 (
> +;   IN      UINT16                    *Value,
> +;   IN      UINT16                    CompareValue,
> +;   IN      UINT16                    ExchangeValue
> +;   );
> +;------------------------------------------------------------------------------
> +InternalSyncCompareExchange16   PROC
> +    mov     eax, edx
> +    lock    cmpxchg [rcx], r8w
> +    ret
> +InternalSyncCompareExchange16   ENDP
> +
> +    END
> diff --git a/OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.c b/OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.c
> new file mode 100644
> index 0000000..64962ba
> --- /dev/null
> +++ b/OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.c
> @@ -0,0 +1,41 @@
> +// Took from BaseSynchronizationLib, and replaced 32 by 16
> +/**
> +  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.
> +
> +
> +  @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 volatile  UINT16           *Value,
> +  IN      UINT16                    CompareValue,
> +  IN      UINT16                    ExchangeValue
> +  )
> +{
> +  __asm__ __volatile__ (
> +    "lock                 \n\t"
> +    "cmpxchgw    %3, %1       "
> +    : "=a" (CompareValue),    // %0
> +      "=m" (*Value)           // %1
> +    : "a"  (CompareValue),    // %2
> +      "r"  (ExchangeValue),   // %3 
> +      "m"  (*Value)
> +    : "memory",
> +      "cc"
> +    );
> +    
> +  return CompareValue;
> +}
> diff --git a/OvmfPkg/XenBusDxe/XenBusDxe.inf b/OvmfPkg/XenBusDxe/XenBusDxe.inf
> index aed2359..612c3db 100644
> --- a/OvmfPkg/XenBusDxe/XenBusDxe.inf
> +++ b/OvmfPkg/XenBusDxe/XenBusDxe.inf
> @@ -33,10 +33,14 @@
>    ComponentName.h
>    XenHypercall.c
>    XenHypercall.h
> +  InterlockedCompareExchange16.h
>  
>  [Sources.X64]
>    X64/hypercall.S
>    X64/hypercall.asm
> +  X64/InterlockedCompareExchange16.c | GCC
> +  X64/InterlockedCompareExchange16.asm | INTEL
> +  InterlockedCompareExchange16Intel.c | INTEL
>  
>  [LibraryClasses]
>    UefiDriverEntryPoint
> -- 
> Anthony PERARD
> 
> 
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