| Message ID | 1423739961-5945-24-git-send-email-ard.biesheuvel@linaro.org |
|---|---|
| State | New |
| Headers | show |
On 23 February 2015 at 15:16, Anthony PERARD <anthony.perard@citrix.com> wrote: > On Thu, Feb 12, 2015 at 07:19:15PM +0800, Ard Biesheuvel wrote: >> 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 >> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> >> --- >> OvmfPkg/XenBusDxe/GrantTable.c | 2 +- >> OvmfPkg/XenBusDxe/Ia32/InterlockedCompareExchange16.nasm | 42 ------------------------------------------ >> OvmfPkg/XenBusDxe/Ia32/TestAndClearBit.nasm | 16 ---------------- >> OvmfPkg/XenBusDxe/InterlockedCompareExchange16.c | 33 --------------------------------- >> OvmfPkg/XenBusDxe/InterlockedCompareExchange16.h | 38 -------------------------------------- >> OvmfPkg/XenBusDxe/TestAndClearBit.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++ >> OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.nasm | 41 ----------------------------------------- >> OvmfPkg/XenBusDxe/X64/TestAndClearBit.nasm | 15 --------------- >> OvmfPkg/XenBusDxe/XenBusDxe.h | 2 +- >> OvmfPkg/XenBusDxe/XenBusDxe.inf | 12 ++---------- >> 10 files changed, 50 insertions(+), 197 deletions(-) >> >> diff --git a/OvmfPkg/XenBusDxe/TestAndClearBit.c b/OvmfPkg/XenBusDxe/TestAndClearBit.c >> new file mode 100644 >> index 000000000000..e971b40a89ce >> --- /dev/null >> +++ b/OvmfPkg/XenBusDxe/TestAndClearBit.c >> @@ -0,0 +1,46 @@ >> +/** @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; >> + 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); >> + >> + Word = *(UINT16 *)Address; >> + Mask = 1U << (Bit & 15); >> + >> + while (Word & Mask) { >> + if (Word == InterlockedCompareExchange16 (Address, Word, Word & ~Mask)) { > > I think there is an infinite loop here, if the value pointed by Address > change between "Word = *Address" and this call to > InterlockedCompareExchange16. > You're quite right. I need to re-read Word at every iteration, something like (with UINT16 Read added): for (Word = *(UINT16 *) Address; Word & Mask; Word = Read) { Read = InterlockedCompareExchange16 (Address, Word, Word & ~Mask); if (Read == Word) { return 1; } } perhaps? >> + return 1; >> + } >> + } >> + return 0; >> +} >> diff --git a/OvmfPkg/XenBusDxe/X64/TestAndClearBit.nasm b/OvmfPkg/XenBusDxe/X64/TestAndClearBit.nasm >> deleted file mode 100644 >> index a4859a62a250..000000000000 >> --- 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 6c306e017b07..953e4b72e85e 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 31553ac5a64a..f0c5db98b1f4 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 > > -- > Anthony PERARD ------------------------------------------------------------------------------ Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration & more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=190641631&iu=/4140/ostg.clktrk
diff --git a/OvmfPkg/XenBusDxe/GrantTable.c b/OvmfPkg/XenBusDxe/GrantTable.c index 19117fbe0373..6e47483f136f 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 d45582dd8109..000000000000 --- 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 d77f74ef249d..000000000000 --- 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 2b0fadd88dd1..000000000000 --- 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 fd3f15b1c8d6..000000000000 --- 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 000000000000..e971b40a89ce --- /dev/null +++ b/OvmfPkg/XenBusDxe/TestAndClearBit.c @@ -0,0 +1,46 @@ +/** @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; + 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); + + Word = *(UINT16 *)Address; + Mask = 1U << (Bit & 15); + + while (Word & Mask) { + if (Word == InterlockedCompareExchange16 (Address, Word, Word & ~Mask)) { + return 1; + } + } + return 0; +} diff --git a/OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.nasm b/OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.nasm deleted file mode 100644 index 048d1f32f6b9..000000000000 --- 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 a4859a62a250..000000000000 --- 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 6c306e017b07..953e4b72e85e 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 31553ac5a64a..f0c5db98b1f4 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
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 Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> --- OvmfPkg/XenBusDxe/GrantTable.c | 2 +- OvmfPkg/XenBusDxe/Ia32/InterlockedCompareExchange16.nasm | 42 ------------------------------------------ OvmfPkg/XenBusDxe/Ia32/TestAndClearBit.nasm | 16 ---------------- OvmfPkg/XenBusDxe/InterlockedCompareExchange16.c | 33 --------------------------------- OvmfPkg/XenBusDxe/InterlockedCompareExchange16.h | 38 -------------------------------------- OvmfPkg/XenBusDxe/TestAndClearBit.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++ OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.nasm | 41 ----------------------------------------- OvmfPkg/XenBusDxe/X64/TestAndClearBit.nasm | 15 --------------- OvmfPkg/XenBusDxe/XenBusDxe.h | 2 +- OvmfPkg/XenBusDxe/XenBusDxe.inf | 12 ++---------- 10 files changed, 50 insertions(+), 197 deletions(-)