Tools/Source/TianoTools/Common/PeiLib/Ipf/SwitchStack.s

   1 //++
   2 // Copyright (c) 2004, Intel Corporation
   3 // All rights reserved. This program and the accompanying materials
   4 // are licensed and made available under the terms and conditions of the BSD License
   5 // which accompanies this distribution.  The full text of the license may be found at
   6 // http://opensource.org/licenses/bsd-license.php
   7 //
   8 // THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
   9 // WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  10 //
  11 // Module Name:
  12 //
  13 //  SwitchStack.s
  14 //
  15 // Abstract:
  16 //
  17 //  Contains an implementation of a stack switch for the Itanium-based architecture.
  18 //
  19 //
  20 //
  21 // Revision History:
  22 //
  23 //--
  24
  25   .file  "SwitchStack.s"
  26
  27 #include  <asm.h>
  28 #include  <ia_64gen.h>
  29
  30 // Define hardware RSE Configuration Register
  31 //
  32 // RS Configuration (RSC) bit field positions
  33
  34 #define RSC_MODE       0
  35 #define RSC_PL         2
  36 #define RSC_BE         4
  37 // RSC bits 5-15 reserved
  38 #define RSC_MBZ0       5
  39 #define RSC_MBZ0_V     0x3ff
  40 #define RSC_LOADRS     16
  41 #define RSC_LOADRS_LEN 14
  42 // RSC bits 30-63 reserved
  43 #define RSC_MBZ1       30
  44 #define RSC_MBZ1_V     0x3ffffffffULL
  45
  46 // RSC modes
  47 // Lazy
  48 #define RSC_MODE_LY (0x0)
  49 // Store intensive
  50 #define RSC_MODE_SI (0x1)
  51 // Load intensive
  52 #define RSC_MODE_LI (0x2)
  53 // Eager
  54 #define RSC_MODE_EA (0x3)
  55
  56 // RSC Endian bit values
  57 #define RSC_BE_LITTLE 0
  58 #define RSC_BE_BIG    1
  59
  60 // RSC while in kernel: enabled, little endian, pl = 0, eager mode
  61 #define RSC_KERNEL ((RSC_MODE_EA<<RSC_MODE) | (RSC_BE_LITTLE<<RSC_BE))
  62 // Lazy RSC in kernel: enabled, little endian, pl = 0, lazy mode
  63 #define RSC_KERNEL_LAZ ((RSC_MODE_LY<<RSC_MODE) | (RSC_BE_LITTLE<<RSC_BE))
  64 // RSE disabled: disabled, pl = 0, little endian, eager mode
  65 #define RSC_KERNEL_DISABLED ((RSC_MODE_LY<<RSC_MODE) | (RSC_BE_LITTLE<<RSC_BE))
  66
  67
  68 //VOID
  69 //SwitchStacks (
  70 //    VOID    *ContinuationFunction,
  71 //    UINTN   Parameter,
  72 //    UINTN   NewTopOfStack,
  73 //    UINTN   NewBSPStore OPTIONAL
  74 //)
  75 ///*++
  76 //
  77 //Input Arguments
  78 //
  79 //  ContinuationFunction - This is a pointer to the PLABEL of the function that should  be called once the
  80 //        new stack has been created.
  81 //  Parameter - The parameter to pass to the continuation function
  82 //  NewTopOfStack - This is the new top of the memory stack for ensuing code.  This is mandatory and
  83 //      should be non-zero
  84 //  NewBSPStore - This is the new BSP store for the ensuing code.  It is optional on IA-32 and mandatory on Itanium-based platform.
  85 //
  86 //--*/
  87
  88 PROCEDURE_ENTRY(SwitchStacks)
  89
  90         mov        r16 = -0x10;;
  91         and        r16 = r34, r16;;             // get new stack value in R16, 0 the last nibble.
  92         mov        r15 = r35;;                  // Get new BspStore into R15
  93         mov        r13 = r32;;                  // this is a pointer to the PLABEL of the continuation function.
  94         mov        r17 = r33;;                  // this is the parameter to pass to the continuation function
  95
  96         alloc       r11=0,0,0,0                 // Set 0-size frame
  97         ;;
  98         flushrs;;
  99
 100         mov         r21 = RSC_KERNEL_DISABLED   // for rse disable
 101         ;;
 102         mov         ar.rsc = r21                // turn off RSE
 103
 104         add         sp = r0, r16;;              // transfer to the EFI stack
 105         mov         ar.bspstore = r15           // switch to EFI BSP
 106         invala                                  // change of ar.bspstore needs invala.
 107
 108         mov         r18 = RSC_KERNEL_LAZ        // RSC enabled, Lazy mode
 109         ;;
 110         mov         ar.rsc = r18                // turn rse on, in kernel mode
 111         ;;
 112         alloc       r11=0,0,1,0;;                 // alloc 0 outs going to ensuing DXE IPL service
 113         mov         out0 = r17
 114         ld8         r16 = [r13],8;;               // r16 = address of continuation function from the PLABEL
 115         ld8         gp = [r13]                  // gp  = gp of continuation function from the PLABEL
 116         mov         b6 = r16
 117         ;;
 118         br.call.sptk.few b0=b6;;                  // Call the continuation function
 119         ;;
 120 PROCEDURE_EXIT(SwitchStacks)
 121
 122