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
This commit is contained in:
oliviermartin 2011-11-08 18:49:22 +00:00
parent 0b6b57c4d7
commit 0806815921
3 changed files with 69 additions and 77 deletions

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@ -1,76 +0,0 @@
/** @file
GCC inline implementation of BaseLib processor specific functions.
Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>
Portions copyright (c) 2008 - 2009, Apple Inc. 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.
**/
#include "BaseLibInternals.h"
/**
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__ __volatile__ (
"nop\n\t"
"nop\n\t"
"nop\n\t"
"nop\n\t"
"nop\n\t"
);
}
/**
Transfers control to a function starting with a new stack.
This internal worker function transfers control to the function
specified by EntryPoint using the new stack specified by NewStack
and passing in the parameters specified by Context1 and Context2.
Context1 and Context2 are optional and may be NULL.
The function EntryPoint must never return.
@param EntryPoint The pointer to the function to enter.
@param Context1 The first parameter to pass in.
@param Context2 The second Parameter to pass in
@param NewStack The new Location of the stack
**/
VOID
EFIAPI
InternalSwitchStackAsm (
SWITCH_STACK_ENTRY_POINT EntryPoint,
VOID *Context1,
VOID *Context2,
VOID *NewStack
)
{
__asm__ __volatile__ (
"mov lr, %0\n\t"
"mov sp, %3\n\t"
"mov %r0, %1\n\t"
"mov %r1, %2\n\t"
"bx lr\n\t"
: /* no output operand */
: "r" (EntryPoint),
"r" (Context1),
"r" (Context2),
"r" (NewStack)
);
}

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@ -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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@ -469,7 +469,7 @@
Arm/CpuBreakpoint.asm | RVCT
Arm/Math64.S | GCC
Arm/GccInline.c | GCC
Arm/SwitchStack.S | GCC
Arm/EnableInterrupts.S | GCC
Arm/DisableInterrupts.S | GCC
Arm/GetInterruptsState.S | GCC