diff options
Diffstat (limited to 'Silicon/BroxtonSoC/BroxtonSiPkg/Cpu/SecCore/Ia32/Stack.S')
-rw-r--r-- | Silicon/BroxtonSoC/BroxtonSiPkg/Cpu/SecCore/Ia32/Stack.S | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/Silicon/BroxtonSoC/BroxtonSiPkg/Cpu/SecCore/Ia32/Stack.S b/Silicon/BroxtonSoC/BroxtonSiPkg/Cpu/SecCore/Ia32/Stack.S new file mode 100644 index 0000000000..a4bcf7f9eb --- /dev/null +++ b/Silicon/BroxtonSoC/BroxtonSiPkg/Cpu/SecCore/Ia32/Stack.S @@ -0,0 +1,75 @@ +## @file
+# Switch the stack from temporary memory to permenent memory.
+#
+# Copyright (c) 2008 - 2016, Intel Corporation. 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
+#
+##
+
+#------------------------------------------------------------------------------
+# VOID
+# EFIAPI
+# SecSwitchStack (
+# UINT32 TemporaryMemoryBase,
+# UINT32 PermenentMemoryBase
+# )
+#------------------------------------------------------------------------------
+ASM_GLOBAL ASM_PFX (SecSwitchStack)
+ASM_PFX(SecSwitchStack):
+ #
+ # Save standard registers so they can be used to change stack
+ #
+ pushl %eax
+ pushl %ebx
+ pushl %ecx
+ pushl %edx
+
+ #
+ # !!CAUTION!! this function address's is pushed into stack after
+ # migration of whole temporary memory, so need save it to permenent
+ # memory at first!
+ #
+ movl 20(%esp), %ebx # Save the first parameter
+ movl 24(%esp), %ecx # Save the second parameter
+
+ #
+ # Save this function's return address into permenent memory at first.
+ # Then, Fixup the esp point to permenent memory
+ #
+ movl %esp, %eax
+ subl %ebx, %eax
+ addl %ecx, %eax
+ movl 0(%esp), %edx # copy pushed register's value to permenent memory
+ movl %edx, 0(%eax)
+ movl 4(%esp), %edx
+ movl %edx, 4(%eax)
+ movl 8(%esp), %edx
+ movl %edx, 8(%eax)
+ movl 12(%esp), %edx
+ movl %edx, 12(%eax)
+ movl 16(%esp), %edx # Update this function's return address into permenent memory
+ movl %edx, 16(%eax)
+ movl %eax, %esp # From now, esp is pointed to permenent memory
+
+ #
+ # Fixup the ebp point to permenent memory
+ #
+ movl %ebp, %eax
+ subl %ebx, %eax
+ addl %ecx, %eax
+ movl %eax, %ebp # From now, ebp is pointed to permenent memory
+
+ popl %edx
+ popl %ecx
+ popl %ebx
+ popl %eax
+ ret
+
+
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