diff options
Diffstat (limited to 'MdeModulePkg/Core/Dxe/Misc')
-rw-r--r-- | MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c b/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c index a73c4ccd64..0fa89e4437 100644 --- a/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c +++ b/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c @@ -996,6 +996,53 @@ MemoryProtectionExitBootServicesCallback ( }
/**
+ Disable NULL pointer detection after EndOfDxe. This is a workaround resort in
+ order to skip unfixable NULL pointer access issues detected in OptionROM or
+ boot loaders.
+
+ @param[in] Event The Event this notify function registered to.
+ @param[in] Context Pointer to the context data registered to the Event.
+**/
+VOID
+EFIAPI
+DisableNullDetectionAtTheEndOfDxe (
+ EFI_EVENT Event,
+ VOID *Context
+ )
+{
+ EFI_STATUS Status;
+ EFI_GCD_MEMORY_SPACE_DESCRIPTOR Desc;
+
+ DEBUG ((DEBUG_INFO, "DisableNullDetectionAtTheEndOfDxe(): start\r\n"));
+ //
+ // Disable NULL pointer detection by enabling first 4K page
+ //
+ Status = CoreGetMemorySpaceDescriptor (0, &Desc);
+ ASSERT_EFI_ERROR (Status);
+
+ if ((Desc.Capabilities & EFI_MEMORY_RP) == 0) {
+ Status = CoreSetMemorySpaceCapabilities (
+ 0,
+ EFI_PAGE_SIZE,
+ Desc.Capabilities | EFI_MEMORY_RP
+ );
+ ASSERT_EFI_ERROR (Status);
+ }
+
+ Status = CoreSetMemorySpaceAttributes (
+ 0,
+ EFI_PAGE_SIZE,
+ Desc.Attributes & ~EFI_MEMORY_RP
+ );
+ ASSERT_EFI_ERROR (Status);
+
+ CoreCloseEvent (Event);
+ DEBUG ((DEBUG_INFO, "DisableNullDetectionAtTheEndOfDxe(): end\r\n"));
+
+ return;
+}
+
+/**
Initialize Memory Protection support.
**/
VOID
@@ -1006,6 +1053,7 @@ CoreInitializeMemoryProtection ( {
EFI_STATUS Status;
EFI_EVENT Event;
+ EFI_EVENT EndOfDxeEvent;
VOID *Registration;
mImageProtectionPolicy = PcdGet32(PcdImageProtectionPolicy);
@@ -1044,6 +1092,23 @@ CoreInitializeMemoryProtection ( );
ASSERT_EFI_ERROR(Status);
}
+
+ //
+ // Register a callback to disable NULL pointer detection at EndOfDxe
+ //
+ if ((PcdGet8 (PcdNullPointerDetectionPropertyMask) & (BIT0|BIT7))
+ == (BIT0|BIT7)) {
+ Status = CoreCreateEventEx (
+ EVT_NOTIFY_SIGNAL,
+ TPL_NOTIFY,
+ DisableNullDetectionAtTheEndOfDxe,
+ NULL,
+ &gEfiEndOfDxeEventGroupGuid,
+ &EndOfDxeEvent
+ );
+ ASSERT_EFI_ERROR (Status);
+ }
+
return ;
}
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