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| author | oliviermartin <oliviermartin@6f19259b-4bc3-4df7-8a09-765794883524> | 2011-11-08 18:49:22 +0000 |
|---|---|---|
| committer | oliviermartin <oliviermartin@6f19259b-4bc3-4df7-8a09-765794883524> | 2011-11-08 18:49:22 +0000 |
| commit | 080681592188f45228616983f9e1610ab9e86615 (patch) | |
| tree | 221023c7fc5939e92be5e74fe7c629d5b82fe04e /MdePkg/Library/BaseLib/Arm/SwitchStack.S | |
| parent | 0b6b57c4d7181ffe805ffd6a60ee8d59fd76348d (diff) | |
| download | edk2-platforms-080681592188f45228616983f9e1610ab9e86615.tar.xz | |
MdePkg/BaseLib: Replaced inline assembly for ARMGCC by GCC assembly source file
The registers used to passed arguments to the DxeCore entrypoint in the inline
assembly function InternalSwitchStackAsm() where switched at compilation time.
This change replaces the inline assembly by a pure assembly source file to
avoid this kind of optimization.
Note: Inline assembly is generally not recommanded in system programming.
Reviewed-by: lgao4
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@12674 6f19259b-4bc3-4df7-8a09-765794883524
Diffstat (limited to 'MdePkg/Library/BaseLib/Arm/SwitchStack.S')
| -rw-r--r-- | MdePkg/Library/BaseLib/Arm/SwitchStack.S | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/MdePkg/Library/BaseLib/Arm/SwitchStack.S b/MdePkg/Library/BaseLib/Arm/SwitchStack.S new file mode 100644 index 0000000000..413de99ba5 --- /dev/null +++ b/MdePkg/Library/BaseLib/Arm/SwitchStack.S @@ -0,0 +1,68 @@ +//------------------------------------------------------------------------------
+//
+// Copyright (c) 2006 - 2009, Intel Corporation. All rights reserved.<BR>
+// Portions copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR>
+// Portions copyright (c) 2011, ARM Limited. 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.
+//
+//------------------------------------------------------------------------------
+
+.text
+.align 5
+
+GCC_ASM_EXPORT(InternalSwitchStackAsm)
+GCC_ASM_EXPORT(CpuPause)
+
+/**
+//
+// This allows the caller to switch the stack and goes to the new entry point
+//
+// @param EntryPoint The pointer to the location to enter
+// @param Context Parameter to pass in
+// @param Context2 Parameter2 to pass in
+// @param NewStack New Location of the stack
+//
+// @return Nothing. Goes to the Entry Point passing in the new parameters
+//
+VOID
+EFIAPI
+InternalSwitchStackAsm (
+ SWITCH_STACK_ENTRY_POINT EntryPoint,
+ VOID *Context,
+ VOID *Context2,
+ VOID *NewStack
+ );
+**/
+ASM_PFX(InternalSwitchStackAsm):
+ MOV LR, R0
+ MOV SP, R3
+ MOV R0, R1
+ MOV R1, R2
+ BX LR
+
+/**
+//
+// Requests CPU to pause for a short period of time.
+//
+// Requests CPU to pause for a short period of time. Typically used in MP
+// systems to prevent memory starvation while waiting for a spin lock.
+//
+VOID
+EFIAPI
+CpuPause (
+ VOID
+ )
+**/
+ASM_PFX(CpuPause):
+ nop
+ nop
+ nop
+ nop
+ nop
+ BX LR
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