450 lines
10 KiB
C
450 lines
10 KiB
C
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/*++
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Copyright (c) 1991 Microsoft Corporation
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Copyright (c) 1992 Digital Equipment Corporation
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Module Name:
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alignem.c
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Abstract:
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This module implements the code necessary to emulate unaligned data
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references.
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Author:
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David N. Cutler (davec) 17-Jun-1991
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Joe Notarangelo 14-May-1992
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Environment:
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Kernel mode only.
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Revision History:
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--*/
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#include "ki.h"
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//
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// Function prototypes for emulation routines
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//
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ULONGLONG
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KiEmulateLoadLong(
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IN PULONG UnalignedAddress
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);
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ULONGLONG
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KiEmulateLoadQuad(
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IN PUQUAD UnalignedAddress
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);
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ULONGLONG
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KiEmulateLoadFloatIEEESingle(
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IN PULONG UnalignedAddress
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);
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ULONGLONG
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KiEmulateLoadFloatIEEEDouble(
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IN PUQUAD UnalignedAddress
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);
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VOID
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KiEmulateStoreLong(
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IN PULONG UnalignedAddress,
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IN ULONGLONG Data
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);
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VOID
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KiEmulateStoreQuad(
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IN PUQUAD UnalignedAddress,
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IN ULONGLONG Data
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);
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VOID
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KiEmulateStoreFloatIEEESingle(
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IN PULONG UnalignedAddress,
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IN ULONGLONG Data
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);
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VOID
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KiEmulateStoreFloatIEEEDouble(
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IN PUQUAD UnalignedAddress,
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IN ULONGLONG Data
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);
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VOID
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KiEnablePALAlignmentFixups(
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VOID
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);
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VOID
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KiDisablePALAlignmentFixups(
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VOID
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);
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VOID
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KiProfileInterrupt(
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IN KPROFILE_SOURCE ProfileSource,
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IN PKTRAP_FRAME TrapFrame
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);
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VOID
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KiEnableAlignmentExceptions(
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VOID
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)
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/*++
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Routine Description:
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Enables alignment exceptions on the current processor by
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disabling automatic PAL code alignment fixups. PAL is
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called to turn off automatic fixups only if CPU is
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21164 or greater.
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Arguments:
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None
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Return Value:
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None
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--*/
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{
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if (KeProcessorLevel >= PROCESSOR_ALPHA_21164) {
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KiDisablePALAlignmentFixups();
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}
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}
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VOID
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KiDisableAlignmentExceptions(
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VOID
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)
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/*++
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Routine Description:
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Disables alignment exceptions on the current processor by
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enabling automatic PAL code alignment fixups. PAL is
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called to turn on automatic fixups only if CPU is
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21164 or greater and KiEnableAlignmentFaultExceptions==0
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If KiEnableAlignmentFaultExceptions is either 1 or 2, then
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the kernel always needs to see alignment faults, so PAL
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automatic alignment fixups should not be enabled
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Arguments:
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None
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Return Value:
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None
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--*/
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{
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if ((KeProcessorLevel >= PROCESSOR_ALPHA_21164) &&
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(KiEnableAlignmentFaultExceptions == 0)) {
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KiEnablePALAlignmentFixups();
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}
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}
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BOOLEAN
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KiEmulateReference (
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IN OUT PEXCEPTION_RECORD ExceptionRecord,
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IN OUT PKEXCEPTION_FRAME ExceptionFrame,
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IN OUT PKTRAP_FRAME TrapFrame
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)
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/*++
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Routine Description:
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Routine emulates an unaligned data reference from user part
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of the address space.
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Arguments:
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ExceptionRecord - Supplies a pointer to the exception record.
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ExceptionFrame - Supplies a pointer to an exception frame.
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TrapFrame - Supplies a pointer to a trap frame
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Return Value:
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True is returned if reference is successfully emulated,
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otherwise False is returned.
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--*/
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{
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ULONGLONG Data;
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PVOID EffectiveAddress;
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PVOID ExceptionAddress;
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ULONG Fa;
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ULONG Opcode;
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KPROCESSOR_MODE PreviousMode;
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ULONG Ra;
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KIRQL OldIrql;
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//
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// Call out to profile interrupt if alignment profiling is active
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//
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if (KiProfileAlignmentFixup) {
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if (++KiProfileAlignmentFixupCount >= KiProfileAlignmentFixupInterval) {
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KeRaiseIrql(PROFILE_LEVEL, &OldIrql);
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KiProfileAlignmentFixupCount = 0;
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KiProfileInterrupt(ProfileAlignmentFixup, TrapFrame);
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KeLowerIrql(OldIrql);
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}
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}
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//
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// Save original exception address in case another exception occurs
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//
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ExceptionAddress = ExceptionRecord->ExceptionAddress;
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//
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// The ExceptionInformation in the ExceptionRecord has already
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// recorded information we need to emulate the access.
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//
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// ExceptionInformation:
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// [0] = opcode
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// [1] = destination register
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// [2] = effective address of access
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Opcode = (ULONG)ExceptionRecord->ExceptionInformation[0];
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Ra = (ULONG)ExceptionRecord->ExceptionInformation[1];
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Fa = Ra + 32; // convert to floating register name for floating opcodes
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EffectiveAddress = (PVOID)ExceptionRecord->ExceptionInformation[2];
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//
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// Capture previous mode from trap frame not current thread.
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//
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PreviousMode = (KPROCESSOR_MODE)(((PSR *)(&TrapFrame->Psr))->MODE);
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//
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// Any exception that occurs during the attempted emulation will cause
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// the emulation to be aborted. The new exception code and information
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// will be copied to the original exception record and FALSE will be
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// returned. If the unaligned access was not from kernel mode then
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// probe the effective address before performing the emulation.
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//
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try {
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switch (Opcode) {
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//
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// load longword
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//
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case LDL_OP:
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if( PreviousMode != KernelMode ){
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ProbeForRead( EffectiveAddress,
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sizeof(LONG),
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sizeof(UCHAR) );
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}
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Data = KiEmulateLoadLong( EffectiveAddress );
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KiSetRegisterValue( Ra,
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Data,
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ExceptionFrame,
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TrapFrame );
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break;
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//
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// load quadword
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//
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case LDQ_OP:
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if( PreviousMode != KernelMode ){
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ProbeForRead( EffectiveAddress,
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sizeof(LONGLONG),
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sizeof(UCHAR) );
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}
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Data = KiEmulateLoadQuad( EffectiveAddress );
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KiSetRegisterValue( Ra,
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Data,
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ExceptionFrame,
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TrapFrame );
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break;
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//
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// load IEEE single float
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//
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case LDS_OP:
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if( PreviousMode != KernelMode ){
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ProbeForRead( EffectiveAddress,
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sizeof(float),
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sizeof(UCHAR) );
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}
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Data = KiEmulateLoadFloatIEEESingle( EffectiveAddress );
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KiSetRegisterValue( Fa,
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Data,
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ExceptionFrame,
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TrapFrame );
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break;
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//
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// load IEEE double float
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//
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case LDT_OP:
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if( PreviousMode != KernelMode ){
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ProbeForRead( EffectiveAddress,
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sizeof(DOUBLE),
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sizeof(UCHAR) );
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}
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Data = KiEmulateLoadFloatIEEEDouble( EffectiveAddress );
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KiSetRegisterValue( Fa,
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Data,
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ExceptionFrame,
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TrapFrame );
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break;
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//
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// Load word unsigned.
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//
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case LDWU_OP :
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if (PreviousMode != KernelMode) {
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ProbeForRead(EffectiveAddress,
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sizeof(SHORT),
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sizeof(UCHAR));
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}
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Data = (ULONGLONG)*(UNALIGNED USHORT *)EffectiveAddress;
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KiSetRegisterValue(Ra,
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Data,
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ExceptionFrame,
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TrapFrame);
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break;
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//
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// store longword
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//
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case STL_OP:
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if( PreviousMode != KernelMode ){
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ProbeForWrite( EffectiveAddress,
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sizeof(LONG),
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sizeof(UCHAR) );
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}
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Data = KiGetRegisterValue( Ra,
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ExceptionFrame,
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TrapFrame );
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KiEmulateStoreLong( EffectiveAddress, (ULONG)Data );
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break;
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//
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// store quadword
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//
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case STQ_OP:
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if( PreviousMode != KernelMode ){
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ProbeForWrite( EffectiveAddress,
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sizeof(LONGLONG),
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sizeof(UCHAR) );
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}
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Data = KiGetRegisterValue( Ra,
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ExceptionFrame,
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TrapFrame );
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KiEmulateStoreQuad( EffectiveAddress, Data );
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break;
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//
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// store IEEE float single
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//
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case STS_OP:
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if( PreviousMode != KernelMode ){
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ProbeForWrite( EffectiveAddress,
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sizeof(float),
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sizeof(UCHAR) );
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}
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Data = KiGetRegisterValue( Fa,
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ExceptionFrame,
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TrapFrame );
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KiEmulateStoreFloatIEEESingle( EffectiveAddress, Data );
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break;
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//
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// store IEEE float double
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//
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case STT_OP:
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if( PreviousMode != KernelMode ){
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ProbeForWrite( EffectiveAddress,
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sizeof(DOUBLE),
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sizeof(UCHAR) );
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}
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Data = KiGetRegisterValue( Fa,
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ExceptionFrame,
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TrapFrame );
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KiEmulateStoreFloatIEEEDouble( EffectiveAddress, Data );
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break;
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//
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// Store word.
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//
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case STW_OP :
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if (PreviousMode != KernelMode) {
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ProbeForWrite(EffectiveAddress,
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sizeof(SHORT),
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sizeof(UCHAR));
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}
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Data = KiGetRegisterValue(Ra,
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ExceptionFrame,
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TrapFrame);
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*(UNALIGNED USHORT *)EffectiveAddress = (USHORT)Data;
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break;
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//
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// all other instructions are not emulated
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//
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default:
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return FALSE;
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}
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TrapFrame->Fir += 4;
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return TRUE;
|
|||
|
|
|
|||
|
|
} except (KiCopyInformation(ExceptionRecord,
|
|||
|
|
(GetExceptionInformation())->ExceptionRecord)) {
|
|||
|
|
|
|||
|
|
//
|
|||
|
|
// Preserve the original exception address
|
|||
|
|
//
|
|||
|
|
|
|||
|
|
ExceptionRecord->ExceptionAddress = ExceptionAddress;
|
|||
|
|
|
|||
|
|
return FALSE;
|
|||
|
|
}
|
|||
|
|
}
|