> v2 changes:
> a. Change the type of mPageTablePoolLock to be BOOLEAN. Related code
> logic is also updated and refined.
> b. Add non-stop mode for freed-memory guard feature
The freed-memory guard feature will cause an infinite calling
of InitializePageTablePool(). This is due to a fact that
AllocateAlignedPages() is used to allocate page table pool memory.
This function will most likely call gBS->FreePages to free unaligned
pages and then cause another round of page attributes change, like
below
FreePages() <===============|
=> SetMemoryAttributes() |
=> <if out of page table> |
=> InitializePageTablePool() |
=> AllocateAlignedPages() |
=> FreePages() ================|
The solution is add a global variable as a lock in page table pool
allocation function and fail any other requests if it has not been
done.
This patch also add non-stop mode for freed-memory guard.
Cc: Laszlo Ersek <ler...@redhat.com>
Cc: Star Zeng <star.z...@intel.com>
Cc: Michael D Kinney <michael.d.kin...@intel.com>
Cc: Jiewen Yao <jiewen....@intel.com>
Cc: Ruiyu Ni <ruiyu...@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jian J Wang <jian.j.w...@intel.com>
---
UefiCpuPkg/CpuDxe/CpuDxe.h | 2 +-
UefiCpuPkg/CpuDxe/CpuPageTable.c | 19 +++++++++++++++++--
2 files changed, 18 insertions(+), 3 deletions(-)
diff --git a/UefiCpuPkg/CpuDxe/CpuDxe.h b/UefiCpuPkg/CpuDxe/CpuDxe.h
index 064ea05bba..3183a3f7f4 100644
--- a/UefiCpuPkg/CpuDxe/CpuDxe.h
+++ b/UefiCpuPkg/CpuDxe/CpuDxe.h
@@ -58,7 +58,7 @@
)
#define HEAP_GUARD_NONSTOP_MODE \
- ((PcdGet8 (PcdHeapGuardPropertyMask) & (BIT6|BIT1|BIT0)) > BIT6)
+ ((PcdGet8 (PcdHeapGuardPropertyMask) & (BIT6|BIT4|BIT1|BIT0)) > BIT6)
#define NULL_DETECTION_NONSTOP_MODE \
((PcdGet8 (PcdNullPointerDetectionPropertyMask) & (BIT6|BIT0)) > BIT6)
diff --git a/UefiCpuPkg/CpuDxe/CpuPageTable.c b/UefiCpuPkg/CpuDxe/CpuPageTable.c
index 33e8ee2d2c..b7beaf935b 100644
--- a/UefiCpuPkg/CpuDxe/CpuPageTable.c
+++ b/UefiCpuPkg/CpuDxe/CpuPageTable.c
@@ -100,6 +100,7 @@ PAGE_ATTRIBUTE_TABLE mPageAttributeTable[] = {
};
PAGE_TABLE_POOL *mPageTablePool = NULL;
+BOOLEAN mPageTablePoolLock = FALSE;
PAGE_TABLE_LIB_PAGING_CONTEXT mPagingContext;
EFI_SMM_BASE2_PROTOCOL *mSmmBase2 = NULL;
@@ -1046,6 +1047,16 @@ InitializePageTablePool (
VOID *Buffer;
BOOLEAN IsModified;
+ //
+ // Do not allow re-entrance.
+ //
+ if (mPageTablePoolLock) {
+ return FALSE;
+ }
+
+ mPageTablePoolLock = TRUE;
+ IsModified = FALSE;
+
//
// Always reserve at least PAGE_TABLE_POOL_UNIT_PAGES, including one page for
// header.
@@ -1056,7 +1067,9 @@ InitializePageTablePool (
Buffer = AllocateAlignedPages (PoolPages, PAGE_TABLE_POOL_ALIGNMENT);
if (Buffer == NULL) {
DEBUG ((DEBUG_ERROR, "ERROR: Out of aligned pages\r\n"));
- return FALSE;
+ goto Done;
+ } else {
+ DEBUG ((DEBUG_INFO, "Paging: added %ld pages to page table pool\r\n",
(UINT64)PoolPages));
}
//
@@ -1092,7 +1105,9 @@ InitializePageTablePool (
);
ASSERT (IsModified == TRUE);
- return TRUE;
+Done:
+ mPageTablePoolLock = FALSE;
+ return IsModified;
}
/**
--
2.16.2.windows.1
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