ArmPlatformPkg/PrePeiCore/PrePeiCoreEntryPoint.S

   1 //
   2 //  Copyright (c) 2011, ARM Limited. All rights reserved.
   3 //
   4 # This program and the accompanying materials
   5 #  are licensed and made available under the terms and conditions of the BSD License
   6 #  which accompanies this distribution.  The full text of the license may be found at
   7 #  http:#opensource.org/licenses/bsd-license.php
   8 #
   9 #  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  10 #  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  11 #
  12 #
  13
  14 #include <AsmMacroIoLib.h>
  15 #include <Base.h>
  16 #include <Library/PcdLib.h>
  17 #include <AutoGen.h>
  18
  19 #start of the code section
  20 .text
  21 .align 3
  22
  23 #global symbols referenced by this module
  24 GCC_ASM_IMPORT(CEntryPoint)
  25
  26 StartupAddr: .word    CEntryPoint
  27
  28 #make _ModuleEntryPoint as global
  29 GCC_ASM_EXPORT(_ModuleEntryPoint)
  30
  31
  32 ASM_PFX(_ModuleEntryPoint):
  33   # Identify CPU ID
  34   mrc   p15, 0, r0, c0, c0, 5
  35   and   r0, #0xf
  36
  37 _SetupStack:
  38   # Setup Stack for the 4 CPU cores
  39   LoadConstantToReg (FixedPcdGet32(PcdCPUCoresNonSecStackBase) ,r1)
  40   LoadConstantToReg (FixedPcdGet32(PcdCPUCoresNonSecStackSize) ,r2)
  41
  42   mov     r3,r0         @ r3 = core_id
  43   mul     r3,r3,r2      @ r3 = core_id * stack_size = offset from the stack base
  44   add     r3,r3,r1      @ r3 = stack_base + offset
  45   add     r3,r3,r2,LSR #1   @ r3 = stack_offset + (stack_size/2)   <-- the top half is for the heap
  46   mov     sp, r3
  47
  48   # lr points to area in reset vector block containing PEI core address. lr needs to
  49   # be saved from the beginning as the _ModuleEntryPoint could call helper functions
  50   # that will overwrite 'lr'
  51   LoadConstantToReg (FixedPcdGet32(PcdNormalFdBaseAddress), r2)
  52   add   r2, r2, #4
  53   ldr   r1, [r2]
  54
  55   # move sec startup address into a data register
  56   # ensure we're jumping to FV version of the code (not boot remapped alias)
  57   ldr   r2, StartupAddr
  58
  59   # jump to PrePeiCore C code
  60   #    r0 = core_id
  61   #    r1 = pei_core_address
  62   blx   r2
  63
  64 .end