EbcSupport.c revision 4fd606d1f5abe38e1f42c38de1d2e895166bd0f4
/** @file
This module contains EBC support routines that are customized based on
the target x64 processor.
Copyright (c) 2006 - 2011, 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
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 "EbcInt.h"
#include "EbcExecute.h"
//
// NOTE: This is the stack size allocated for the interpreter
// when it executes an EBC image. The requirements can change
// based on whether or not a debugger is present, and other
// platform-specific configurations.
//
//
// This is instruction buffer used to create EBC thunk
//
#define EBC_ENTRYPOINT_SIGNATURE 0xAFAFAFAFAFAFAFAFull
#define EBC_LL_EBC_ENTRYPOINT_SIGNATURE 0xFAFAFAFAFAFAFAFAull
//
// Add a magic code here to help the VM recognize the thunk..
// mov rax, 0xca112ebcca112ebc => 48 B8 BC 2E 11 CA BC 2E 11 CA
//
0x48, 0xB8, 0xBC, 0x2E, 0x11, 0xCA, 0xBC, 0x2E, 0x11, 0xCA,
//
// Add code bytes to load up a processor register with the EBC entry point.
// mov r10, EbcEntryPoint => 49 BA XX XX XX XX XX XX XX XX (To be fixed at runtime)
// These 8 bytes of the thunk entry is the address of the EBC
// entry point.
//
0x49, 0xBA,
//
// Stick in a load of r11 with the address of appropriate VM function.
// mov r11, EbcLLEbcInterpret => 49 BB XX XX XX XX XX XX XX XX (To be fixed at runtime)
//
0x49, 0xBB,
//
// Stick in jump opcode bytes
// jmp r11 => 41 FF E3
//
0x41, 0xFF, 0xE3,
};
/**
Begin executing an EBC image.
This is used for Ebc Thunk call.
@return The value returned by the EBC application we're going to run.
**/
);
/**
Begin executing an EBC image.
This is used for Ebc image entrypoint.
@return The value returned by the EBC application we're going to run.
**/
);
/**
Pushes a 64 bit unsigned value to the VM stack.
@param VmPtr The pointer to current VM context.
@param Arg The value to be pushed.
**/
PushU64 (
)
{
//
// Advance the VM stack down, and then copy the argument to the stack.
// Hope it's aligned.
//
return;
}
/**
Begin executing an EBC image.
This is a thunk function. Microsoft x64 compiler only provide fast_call
calling convention, so the first four arguments are passed by rcx, rdx,
r8, and r9, while other arguments are passed in stack.
@param EntryPoint The entrypoint of EBC code.
@param Arg1 The 1st argument.
@param Arg2 The 2nd argument.
@param Arg3 The 3rd argument.
@param Arg4 The 4th argument.
@param Arg5 The 5th argument.
@param Arg6 The 6th argument.
@param Arg7 The 7th argument.
@param Arg8 The 8th argument.
@param Arg9 The 9th argument.
@param Arg10 The 10th argument.
@param Arg11 The 11th argument.
@param Arg12 The 12th argument.
@param Arg13 The 13th argument.
@param Arg14 The 14th argument.
@param Arg15 The 15th argument.
@param Arg16 The 16th argument.
@return The value returned by the EBC application we're going to run.
**/
)
{
//
// Create a new VM context on the stack
//
//
// Get the EBC entry point
//
Addr = EntryPoint;
//
// Now clear out our context
//
//
// Set the VM instruction pointer to the correct location in memory.
//
//
// Initialize the stack pointer for the EBC. Get the current system stack
// pointer and adjust it down by the max needed for the interpreter.
//
//
// Adjust the VM's stack pointer down.
//
return Status;
}
//
// Align the stack on a natural boundary.
//
//
// Put a magic value in the stack gap, then adjust down again.
//
//
// The stack upper to LowStackTop is belong to the VM.
//
//
// For the worst case, assume there are 4 arguments passed in registers, store
// them to VM's stack.
//
//
// Interpreter assumes 64-bit return address is pushed on the stack.
// The x64 does not do this so pad the stack accordingly.
//
//
// For x64, this is where we say our return address is
//
//
// We need to keep track of where the EBC stack starts. This way, if the EBC
// accesses any stack variables above its initial stack setting, then we know
// it's accessing variables passed into it, which means the data is on the
// VM's stack.
// When we're called, on the stack (high to low) we have the parameters, the
// return address, then the saved ebp. Save the pointer to the return address.
// EBC code knows that's there, so should look above it for function parameters.
// The offset is the size of locals (VMContext + Addr + saved ebp).
// Note that the interpreter assumes there is a 16 bytes of return address on
// the stack too, so adjust accordingly.
// VmContext.HighStackBottom = (UINTN)(Addr + sizeof (VmContext) + sizeof (Addr));
//
//
// Begin executing the EBC code
//
EbcExecute (&VmContext);
//
// Return the value in R[7] unless there was an error
//
}
/**
Begin executing an EBC image.
@param EntryPoint The entrypoint of EBC code.
@param ImageHandle image handle for the EBC application we're executing
@param SystemTable standard system table passed into an driver's entry
point
@return The value returned by the EBC application we're going to run.
**/
)
{
//
// Create a new VM context on the stack
//
//
// Get the EBC entry point
//
Addr = EntryPoint;
//
// Now clear out our context
//
//
// Save the image handle so we can track the thunks created for this image
//
//
// Set the VM instruction pointer to the correct location in memory.
//
//
// Initialize the stack pointer for the EBC. Get the current system stack
// pointer and adjust it down by the max needed for the interpreter.
//
return Status;
}
//
// Put a magic value in the stack gap, then adjust down again
//
//
// Align the stack on a natural boundary
//
//
// Simply copy the image handle and system table onto the EBC stack.
// Greatly simplifies things by not having to spill the args.
//
//
// VM pushes 16-bytes for return address. Simulate that here.
//
//
// For x64, this is where we say our return address is
//
//
// Entry function needn't access high stack context, simply
// put the stack pointer here.
//
//
// Begin executing the EBC code
//
EbcExecute (&VmContext);
//
// Return the value in R[7] unless there was an error
//
}
/**
Create thunks for an EBC image entry point, or an EBC protocol service.
@param ImageHandle Image handle for the EBC image. If not null, then
we're creating a thunk for an image entry point.
@param EbcEntryPoint Address of the EBC code that the thunk is to call
@param Thunk Returned thunk we create here
@param Flags Flags indicating options for creating the thunk
@retval EFI_SUCCESS The thunk was created successfully.
@retval EFI_INVALID_PARAMETER The parameter of EbcEntryPoint is not 16-bit
aligned.
@retval EFI_OUT_OF_RESOURCES There is not enough memory to created the EBC
Thunk.
@retval EFI_BUFFER_TOO_SMALL EBC_THUNK_SIZE is not larger enough.
**/
)
{
//
// Check alignment of pointer to EBC code
//
return EFI_INVALID_PARAMETER;
}
ThunkSize = sizeof(mInstructionBufferTemplate);
return EFI_OUT_OF_RESOURCES;
}
//
// Print(L"Allocate TH: 0x%X\n", (UINT32)Ptr);
//
// Save the start address so we can add a pointer to it to a list later.
//
//
// Give them the address of our buffer we're going to fix up
//
//
// Copy whole thunk instruction buffer template
//
//
// Patch EbcEntryPoint and EbcLLEbcInterpret
//
}
if ((Flags & FLAG_THUNK_ENTRY_POINT) != 0) {
} else {
}
}
}
//
// Add the thunk to the list for this image. Do this last since the add
// function flushes the cache for us.
//
return EFI_SUCCESS;
}
/**
This function is called to execute an EBC CALLEX instruction.
The function check the callee's content to see whether it is common native
code or a thunk to another piece of EBC code.
If the callee is common native code, use EbcLLCAllEXASM to manipulate,
otherwise, set the VM->IP to target EBC code directly to avoid another VM
be startup which cost time and stack space.
@param VmPtr Pointer to a VM context.
@param FuncAddr Callee's address
@param NewStackPointer New stack pointer after the call
@param FramePtr New frame pointer after the call
@param Size The size of call instruction
**/
)
{
IsThunk = 1;
TargetEbcAddr = 0;
IndexOfEbcEntrypoint = 0;
//
// Processor specific code to check whether the callee is a thunk to EBC.
//
//
// Fill the signature according to mInstructionBufferTemplate
//
}
}
}
//
// Check if we need thunk to native
//
if (CompareMem (InstructionBuffer, mInstructionBufferTemplate, sizeof(mInstructionBufferTemplate)) != 0) {
IsThunk = 0;
}
if (IsThunk == 1){
//
// The callee is a thunk to EBC, adjust the stack pointer down 16 bytes and
// put our return address and frame pointer on the VM stack.
// Then set the VM's IP to new EBC code.
//
} else {
//
// The callee is not a thunk to EBC, call native code,
// and get return value.
//
//
// Advance the IP.
//
}
}