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| author | Jian J Wang <jian.j.wang@intel.com> | 2017-10-09 21:58:55 +0800 |
|---|---|---|
| committer | Eric Dong <eric.dong@intel.com> | 2017-10-11 16:39:01 +0800 |
| commit | a7181d952fcd0b03c423cef99b6e8bf93d9cb1f1 (patch) | |
| tree | 700c32b1c52c51fbf740a1d7d5a62b6ea459e4d8 /MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c | |
| parent | 9189ec20b9e22fe1ec61caefa47a3b3a3cad23a3 (diff) | |
| download | edk2-a7181d952fcd0b03c423cef99b6e8bf93d9cb1f1.tar.gz edk2-a7181d952fcd0b03c423cef99b6e8bf93d9cb1f1.tar.bz2 edk2-a7181d952fcd0b03c423cef99b6e8bf93d9cb1f1.zip | |
MdeModulePkg/Core/Dxe: Add EndOfDxe workaround for NULL pointer detection
One of issue caused by enabling NULL pointer detection is that some PCI
device OptionROM, binary drivers and binary OS boot loaders may have NULL
pointer access bugs, which will prevent BIOS from booting and is almost
impossible to fix. BIT7 of PCD PcdNullPointerDetectionPropertyMask is used
as a workaround to indicate BIOS to disable NULL pointer detection right
after event gEfiEndOfDxeEventGroupGuid, and then let boot continue.
Cc: Star Zeng <star.zeng@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Michael Kinney <michael.d.kinney@intel.com>
Cc: Ayellet Wolman <ayellet.wolman@intel.com>
Suggested-by: Ayellet Wolman <ayellet.wolman@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Diffstat (limited to 'MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c')
| -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 ;
}
|