Add two functions to disable/enable CR0.WP. These two unctions
will also be used in later commits. This commit doesn't change any
functionality.
Signed-off-by: Dun Tan <dun....@intel.com>
Cc: Eric Dong <eric.d...@intel.com>
Reviewed-by: Ray Ni <ray...@intel.com>
Cc: Rahul Kumar <rahul1.ku...@intel.com>
Cc: Gerd Hoffmann <kra...@redhat.com>
---
UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.h | 24
++++++++++++++++++++++++
UefiCpuPkg/PiSmmCpuDxeSmm/SmmCpuMemoryManagement.c | 115
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-------------------------------------------------
2 files changed, 90 insertions(+), 49 deletions(-)
diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.h
b/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.h
index ba341cadc6..e0c4ca76dc 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.h
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.h
@@ -1565,4 +1565,28 @@ SmmWaitForApArrival (
VOID
);
+/**
+ Disable Write Protect on pages marked as read-only if Cr0.Bits.WP is 1.
+
+ @param[out] WpEnabled If Cr0.WP is enabled.
+ @param[out] CetEnabled If CET is enabled.
+**/
+VOID
+DisableReadOnlyPageWriteProtect (
+ OUT BOOLEAN *WpEnabled,
+ OUT BOOLEAN *CetEnabled
+ );
+
+/**
+ Enable Write Protect on pages marked as read-only.
+
+ @param[out] WpEnabled If Cr0.WP should be enabled.
+ @param[out] CetEnabled If CET should be enabled.
+**/
+VOID
+EnableReadOnlyPageWriteProtect (
+ BOOLEAN WpEnabled,
+ BOOLEAN CetEnabled
+ );
+
#endif
diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/SmmCpuMemoryManagement.c
b/UefiCpuPkg/PiSmmCpuDxeSmm/SmmCpuMemoryManagement.c
index 3c79927c7b..d35058ed00 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/SmmCpuMemoryManagement.c
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/SmmCpuMemoryManagement.c
@@ -40,6 +40,64 @@ PAGE_TABLE_POOL *mPageTablePool = NULL;
//
BOOLEAN mIsReadOnlyPageTable = FALSE;
+/**
+ Disable Write Protect on pages marked as read-only if Cr0.Bits.WP is 1.
+
+ @param[out] WpEnabled If Cr0.WP is enabled.
+ @param[out] CetEnabled If CET is enabled.
+**/
+VOID
+DisableReadOnlyPageWriteProtect (
+ OUT BOOLEAN *WpEnabled,
+ OUT BOOLEAN *CetEnabled
+ )
+{
+ IA32_CR0 Cr0;
+
+ *CetEnabled = ((AsmReadCr4 () & CR4_CET_ENABLE) != 0) ? TRUE : FALSE;
+ Cr0.UintN = AsmReadCr0 ();
+ *WpEnabled = (Cr0.Bits.WP != 0) ? TRUE : FALSE;
+ if (*WpEnabled) {
+ if (*CetEnabled) {
+ //
+ // CET must be disabled if WP is disabled. Disable CET before clearing
CR0.WP.
+ //
+ DisableCet ();
+ }
+
+ Cr0.Bits.WP = 0;
+ AsmWriteCr0 (Cr0.UintN);
+ }
+}
+
+/**
+ Enable Write Protect on pages marked as read-only.
+
+ @param[out] WpEnabled If Cr0.WP should be enabled.
+ @param[out] CetEnabled If CET should be enabled.
+**/
+VOID
+EnableReadOnlyPageWriteProtect (
+ BOOLEAN WpEnabled,
+ BOOLEAN CetEnabled
+ )
+{
+ IA32_CR0 Cr0;
+
+ if (WpEnabled) {
+ Cr0.UintN = AsmReadCr0 ();
+ Cr0.Bits.WP = 1;
+ AsmWriteCr0 (Cr0.UintN);
+
+ if (CetEnabled) {
+ //
+ // re-enable CET.
+ //
+ EnableCet ();
+ }
+ }
+}
+
/**
Initialize a buffer pool for page table use only.
@@ -62,10 +120,9 @@ InitializePageTablePool (
IN UINTN PoolPages
)
{
- VOID *Buffer;
- BOOLEAN CetEnabled;
- BOOLEAN WpEnabled;
- IA32_CR0 Cr0;
+ VOID *Buffer;
+ BOOLEAN WpEnabled;
+ BOOLEAN CetEnabled;
//
// Always reserve at least PAGE_TABLE_POOL_UNIT_PAGES, including one page for
@@ -102,34 +159,9 @@ InitializePageTablePool (
// If page table memory has been marked as RO, mark the new pool pages as
read-only.
//
if (mIsReadOnlyPageTable) {
- CetEnabled = ((AsmReadCr4 () & CR4_CET_ENABLE) != 0) ? TRUE : FALSE;
- Cr0.UintN = AsmReadCr0 ();
- WpEnabled = (Cr0.Bits.WP != 0) ? TRUE : FALSE;
- if (WpEnabled) {
- if (CetEnabled) {
- //
- // CET must be disabled if WP is disabled. Disable CET before clearing
CR0.WP.
- //
- DisableCet ();
- }
-
- Cr0.Bits.WP = 0;
- AsmWriteCr0 (Cr0.UintN);
- }
-
+ DisableReadOnlyPageWriteProtect (&WpEnabled, &CetEnabled);
SmmSetMemoryAttributes ((EFI_PHYSICAL_ADDRESS)(UINTN)Buffer,
EFI_PAGES_TO_SIZE (PoolPages), EFI_MEMORY_RO);
- if (WpEnabled) {
- Cr0.UintN = AsmReadCr0 ();
- Cr0.Bits.WP = 1;
- AsmWriteCr0 (Cr0.UintN);
-
- if (CetEnabled) {
- //
- // re-enable CET.
- //
- EnableCet ();
- }
- }
+ EnableReadOnlyPageWriteProtect (WpEnabled, CetEnabled);
}
return TRUE;
@@ -1780,6 +1812,7 @@ SetPageTableAttributes (
VOID
)
{
+ BOOLEAN WpEnabled;
BOOLEAN CetEnabled;
if (!IfReadOnlyPageTableNeeded ()) {
@@ -1792,15 +1825,7 @@ SetPageTableAttributes (
// Disable write protection, because we need mark page table to be write
protected.
// We need *write* page table memory, to mark itself to be *read only*.
//
- CetEnabled = ((AsmReadCr4 () & CR4_CET_ENABLE) != 0) ? TRUE : FALSE;
- if (CetEnabled) {
- //
- // CET must be disabled if WP is disabled.
- //
- DisableCet ();
- }
-
- AsmWriteCr0 (AsmReadCr0 () & ~CR0_WP);
+ DisableReadOnlyPageWriteProtect (&WpEnabled, &CetEnabled);
// Set memory used by page table as Read Only.
DEBUG ((DEBUG_INFO, "Start...\n"));
@@ -1809,20 +1834,12 @@ SetPageTableAttributes (
//
// Enable write protection, after page table attribute updated.
//
- AsmWriteCr0 (AsmReadCr0 () | CR0_WP);
+ EnableReadOnlyPageWriteProtect (TRUE, CetEnabled);
mIsReadOnlyPageTable = TRUE;
//
// Flush TLB after mark all page table pool as read only.
//
FlushTlbForAll ();
-
- if (CetEnabled) {
- //
- // re-enable CET.
- //
- EnableCet ();
- }
-
return;
}
--
2.31.1.windows.1
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