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MdeModulePkg/Core: fix bits operation error on a boundary condition 

If given address is on 64K boundary and the requested bit number is 64,
all SetBits(), ClearBits() and GetBits() will encounter ASSERT problem
in trying to do a 64 bits of shift, which is not allowed by LShift() and
RShift(). This patch tries to fix this issue by turning bits operation
into whole integer operation in such situation.

Cc: Star Zeng <star.zeng@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com>
This commit is contained in:
Jian J Wang 2018-03-15 12:45:43 +08:00 committed by Star Zeng
parent 883787a2c6
commit 36f2f049a8
1 changed files with 10 additions and 6 deletions
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8
MdeModulePkg/Core/Dxe/Mem/HeapGuard.c
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@ -70,7 +70,7 @@ SetBits (
StartBit = (UINTN)GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address); StartBit = (UINTN)GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address);
EndBit = (StartBit + BitNumber - 1) % GUARDED_HEAP_MAP_ENTRY_BITS; EndBit = (StartBit + BitNumber - 1) % GUARDED_HEAP_MAP_ENTRY_BITS;
if ((StartBit + BitNumber) > GUARDED_HEAP_MAP_ENTRY_BITS) { if ((StartBit + BitNumber) >= GUARDED_HEAP_MAP_ENTRY_BITS) {
Msbs = (GUARDED_HEAP_MAP_ENTRY_BITS - StartBit) % Msbs = (GUARDED_HEAP_MAP_ENTRY_BITS - StartBit) %
GUARDED_HEAP_MAP_ENTRY_BITS; GUARDED_HEAP_MAP_ENTRY_BITS;
Lsbs = (EndBit + 1) % GUARDED_HEAP_MAP_ENTRY_BITS; Lsbs = (EndBit + 1) % GUARDED_HEAP_MAP_ENTRY_BITS;
@ -123,7 +123,7 @@ ClearBits (
StartBit = (UINTN)GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address); StartBit = (UINTN)GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address);
EndBit = (StartBit + BitNumber - 1) % GUARDED_HEAP_MAP_ENTRY_BITS; EndBit = (StartBit + BitNumber - 1) % GUARDED_HEAP_MAP_ENTRY_BITS;
if ((StartBit + BitNumber) > GUARDED_HEAP_MAP_ENTRY_BITS) { if ((StartBit + BitNumber) >= GUARDED_HEAP_MAP_ENTRY_BITS) {
Msbs = (GUARDED_HEAP_MAP_ENTRY_BITS - StartBit) % Msbs = (GUARDED_HEAP_MAP_ENTRY_BITS - StartBit) %
GUARDED_HEAP_MAP_ENTRY_BITS; GUARDED_HEAP_MAP_ENTRY_BITS;
Lsbs = (EndBit + 1) % GUARDED_HEAP_MAP_ENTRY_BITS; Lsbs = (EndBit + 1) % GUARDED_HEAP_MAP_ENTRY_BITS;
@ -188,11 +188,15 @@ GetBits (
Lsbs = 0; Lsbs = 0;
} }
if (StartBit == 0 && BitNumber == GUARDED_HEAP_MAP_ENTRY_BITS) {
Result = *BitMap;
} else {
Result = RShiftU64((*BitMap), StartBit) & (LShiftU64(1, Msbs) - 1); Result = RShiftU64((*BitMap), StartBit) & (LShiftU64(1, Msbs) - 1);
if (Lsbs > 0) { if (Lsbs > 0) {
BitMap += 1; BitMap += 1;
Result |= LShiftU64 ((*BitMap) & (LShiftU64 (1, Lsbs) - 1), Msbs); Result |= LShiftU64 ((*BitMap) & (LShiftU64 (1, Lsbs) - 1), Msbs);
} }
}
return Result; return Result;
} }