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Use ReadUnaligned16 function to access the buffer which is pointed by a possible unaligned pointer. 

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@13879 6f19259b-4bc3-4df7-8a09-765794883524
This commit is contained in:
li-elvin 2012-10-24 01:10:47 +00:00
parent 151304d96d
commit e6fa789014
1 changed files with 11 additions and 5 deletions
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16
IntelFrameworkModulePkg/Csm/BiosThunk/VideoDxe/BiosVideo.c
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@ -1262,6 +1262,7 @@ BiosVideoCheckForVbe (
EFI_STATUS Status;
EFI_IA32_REGISTER_SET Regs;
UINT16 *ModeNumberPtr;
UINT16 VbeModeNumber;
BOOLEAN ModeFound;
BOOLEAN EdidFound;
BIOS_VIDEO_MODE_DATA *ModeBuffer;
@ -1477,12 +1478,17 @@ BiosVideoCheckForVbe (
PreferMode = 0;
ModeNumber = 0;
for (; *ModeNumberPtr != VESA_BIOS_EXTENSIONS_END_OF_MODE_LIST; ModeNumberPtr++) {
//
// ModeNumberPtr may be not 16-byte aligned, so ReadUnaligned16 is used to access the buffer pointed by ModeNumberPtr.
//
for (VbeModeNumber = ReadUnaligned16 (ModeNumberPtr);
VbeModeNumber != VESA_BIOS_EXTENSIONS_END_OF_MODE_LIST;
VbeModeNumber = ReadUnaligned16 (++ModeNumberPtr)) {
//
// Make sure this is a mode number defined by the VESA VBE specification. If it isn'tm then skip this mode number.
//
if ((*ModeNumberPtr & VESA_BIOS_EXTENSIONS_MODE_NUMBER_VESA) == 0) {
if ((VbeModeNumber & VESA_BIOS_EXTENSIONS_MODE_NUMBER_VESA) == 0) {
continue;
}
//
@ -1490,7 +1496,7 @@ BiosVideoCheckForVbe (
//
gBS->SetMem (&Regs, sizeof (Regs), 0);
Regs.X.AX = VESA_BIOS_EXTENSIONS_RETURN_MODE_INFORMATION;
Regs.X.CX = *ModeNumberPtr;
Regs.X.CX = VbeModeNumber;
gBS->SetMem (BiosVideoPrivate->VbeModeInformationBlock, sizeof (VESA_BIOS_EXTENSIONS_MODE_INFORMATION_BLOCK), 0);
Regs.X.ES = EFI_SEGMENT ((UINTN) BiosVideoPrivate->VbeModeInformationBlock);
Regs.X.DI = EFI_OFFSET ((UINTN) BiosVideoPrivate->VbeModeInformationBlock);
@ -1619,7 +1625,7 @@ BiosVideoCheckForVbe (
}
CurrentModeData = &ModeBuffer[ModeNumber - 1];
CurrentModeData->VbeModeNumber = *ModeNumberPtr;
CurrentModeData->VbeModeNumber = VbeModeNumber;
if (BiosVideoPrivate->VbeInformationBlock->VESAVersion >= VESA_BIOS_EXTENSIONS_VERSION_3_0) {
CurrentModeData->BytesPerScanLine = BiosVideoPrivate->VbeModeInformationBlock->LinBytesPerScanLine;
CurrentModeData->Red.Position = BiosVideoPrivate->VbeModeInformationBlock->LinRedFieldPosition;