fab82c1873
The AP startup code simply jumps into this code with the CpuDxe driver
without setting up a stack for the processor.
Therefore, this code must setup the stack before calling into C code.
This is the basic flow:
* AP enters CpuDxe driver code (AsmApEntryPoint) without stack
- AP grabs a lock
- AP sets up stack
- AP calls CpuMp.c:ApEntryPointInC
- If ApEntryPointInC returns, the lock is freed, and another AP may
run
- The AP C code may call AsmApDoneWithCommonStack to indicate that
the AP is no longer using the stack, and another may therefore
proceed to use the stack and then call ApEntryPointInC
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Jeff Fan <jeff.fan@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16347 6f19259b-4bc3-4df7-8a09-765794883524
71 lines
1.9 KiB
NASM
71 lines
1.9 KiB
NASM
;------------------------------------------------------------------------------
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;
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; Copyright (c) 2006 - 2014, Intel Corporation. All rights reserved.<BR>
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; This program and the accompanying materials
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; are licensed and made available under the terms and conditions of the BSD License
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; which accompanies this distribution. The full text of the license may be found at
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; http://opensource.org/licenses/bsd-license.php.
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;
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; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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;
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;------------------------------------------------------------------------------
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extern ASM_PFX(mTopOfApCommonStack)
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extern ASM_PFX(ApEntryPointInC)
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DEFAULT REL
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SECTION .data
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;
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; This lock only allows one AP to use the mTopOfApCommonStack stack at a time
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;
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ApStackLock:
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dd 0
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SECTION .text
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;------------------------------------------------------------------------------
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; VOID
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; EFIAPI
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; AsmApEntryPoint (
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; VOID
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; );
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;------------------------------------------------------------------------------
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global ASM_PFX(AsmApEntryPoint)
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ASM_PFX(AsmApEntryPoint):
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cli
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AsmApEntryPointAcquireLock:
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lock bts dword [ApStackLock], 0
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pause
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jc AsmApEntryPointAcquireLock
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mov rsp, [ASM_PFX(mTopOfApCommonStack)]
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call ASM_PFX(ApEntryPointInC)
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cli
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lock btc dword [ApStackLock], 0
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mov eax, 0x100
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AsmApEntryPointShareLock:
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pause
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dec eax
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jnz AsmApEntryPointShareLock
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jmp ASM_PFX(AsmApEntryPoint)
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;------------------------------------------------------------------------------
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; VOID
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; EFIAPI
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; AsmApDoneWithCommonStack (
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; VOID
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; );
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;------------------------------------------------------------------------------
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global ASM_PFX(AsmApDoneWithCommonStack)
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ASM_PFX(AsmApDoneWithCommonStack):
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lock btc dword [ApStackLock], 0
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ret
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