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IntelFrameworkModulePkg/Csm: Add code to bypass NULL pointer detection

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Legacy has to access interrupt vector, BDA, etc. located in memory between
0-4095. To allow as much code as possible to be monitored by NULL pointer
detection, we add code to temporarily disable this feature right before
those memory access and enable it again afterwards.

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: Jiewen Yao <jiewen.yao@intel.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>
This commit is contained in:
Jian J Wang
2017-10-09 22:01:49 +08:00
committed by Eric Dong
parent f8c1133bbb
commit d057d8c4e9
10 changed files with 338 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files

152
IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBios.c
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@@ -40,6 +40,7 @@ VOID *mRuntimeSmbiosEntryPoint = NULL;
EFI_PHYSICAL_ADDRESS mReserveSmbiosEntryPoint = 0;
EFI_PHYSICAL_ADDRESS mStructureTableAddress = 0;
UINTN mStructureTablePages = 0;
BOOLEAN mEndOfDxe = FALSE;
/**
Do an AllocatePages () of type AllocateMaxAddress for EfiBootServicesCode
@@ -765,6 +766,135 @@ InstallSmbiosEventCallback (
}
}
/**
Callback function to toggle EndOfDxe status. NULL pointer detection needs
this status to decide if it's necessary to change attributes of page 0.
@param Event Event whose notification function is being invoked.
@param Context The pointer to the notification function's context,
which is implementation-dependent.
**/
VOID
EFIAPI
ToggleEndOfDxeStatus (
IN EFI_EVENT Event,
IN VOID *Context
)
{
mEndOfDxe = TRUE;
return;
}
//
// Legacy BIOS needs to access memory between 0-4095, which will cause page
// fault exception if NULL pointer detection mechanism is enabled. Following
// functions can be used to disable/enable NULL pointer detection before/after
// accessing those memory.
//
/**
Enable NULL pointer detection
*/
VOID
EnableNullDetection (
VOID
)
{
EFI_STATUS Status;
EFI_GCD_MEMORY_SPACE_DESCRIPTOR Desc;
if (((PcdGet8 (PcdNullPointerDetectionPropertyMask) & BIT0) == 0)
||
((mEndOfDxe == TRUE) &&
((PcdGet8 (PcdNullPointerDetectionPropertyMask) & (BIT7|BIT0))
== (BIT7|BIT0)))
) {
return;
}
//
// Check current capabilities and attributes
//
Status = gDS->GetMemorySpaceDescriptor (0, &Desc);
ASSERT_EFI_ERROR (Status);
//
// Try to add EFI_MEMORY_RP support if necessary
//
if ((Desc.Capabilities & EFI_MEMORY_RP) == 0) {
Desc.Capabilities |= EFI_MEMORY_RP;
Status = gDS->SetMemorySpaceCapabilities (0, EFI_PAGES_TO_SIZE(1),
Desc.Capabilities);
ASSERT_EFI_ERROR (Status);
if (EFI_ERROR (Status)) {
return;
}
}
//
// Don't bother if EFI_MEMORY_RP is already set.
//
if ((Desc.Attributes & EFI_MEMORY_RP) == 0) {
Desc.Attributes |= EFI_MEMORY_RP;
Status = gDS->SetMemorySpaceAttributes (0, EFI_PAGES_TO_SIZE(1),
Desc.Attributes);
ASSERT_EFI_ERROR (Status);
}
}
/**
Disable NULL pointer detection
*/
VOID
DisableNullDetection (
VOID
)
{
EFI_STATUS Status;
EFI_GCD_MEMORY_SPACE_DESCRIPTOR Desc;
if (((PcdGet8 (PcdNullPointerDetectionPropertyMask) & BIT0) == 0)
||
((mEndOfDxe == TRUE) &&
((PcdGet8 (PcdNullPointerDetectionPropertyMask) & (BIT7|BIT0))
== (BIT7|BIT0)))
) {
return;
}
//
// Check current capabilities and attributes
//
Status = gDS->GetMemorySpaceDescriptor (0, &Desc);
ASSERT_EFI_ERROR (Status);
//
// Try to add EFI_MEMORY_RP support if necessary
//
if ((Desc.Capabilities & EFI_MEMORY_RP) == 0) {
Desc.Capabilities |= EFI_MEMORY_RP;
Status = gDS->SetMemorySpaceCapabilities (0, EFI_PAGES_TO_SIZE(1),
Desc.Capabilities);
ASSERT_EFI_ERROR (Status);
if (EFI_ERROR (Status)) {
return;
}
}
//
// Don't bother if EFI_MEMORY_RP is already cleared.
//
if ((Desc.Attributes & EFI_MEMORY_RP) != 0) {
Desc.Attributes &= ~EFI_MEMORY_RP;
Status = gDS->SetMemorySpaceAttributes (0, EFI_PAGES_TO_SIZE(1),
Desc.Attributes);
ASSERT_EFI_ERROR (Status);
} else {
DEBUG ((DEBUG_WARN, "!!! Page 0 is supposed to be disabled !!!\r\n"));
}
}
/**
Install Driver to produce Legacy BIOS protocol.
@@ -802,6 +932,7 @@ LegacyBiosInstall (
UINT64 Length;
UINT8 *SecureBoot;
EFI_EVENT InstallSmbiosEvent;
EFI_EVENT EndOfDxeEvent;
//
// Load this driver's image to memory
@@ -964,8 +1095,10 @@ LegacyBiosInstall (
// Initialize region from 0x0000 to 4k. This initializes interrupt vector
// range.
//
DisableNullDetection ();
gBS->SetMem ((VOID *) ClearPtr, 0x400, INITIAL_VALUE_BELOW_1K);
ZeroMem ((VOID *) ((UINTN)ClearPtr + 0x400), 0xC00);
EnableNullDetection ();
//
// Allocate pages for OPROM usage
@@ -1104,12 +1237,17 @@ LegacyBiosInstall (
//
// Save Unexpected interrupt vector so can restore it just prior to boot
//
DisableNullDetection ();
BaseVectorMaster = (UINT32 *) (sizeof (UINT32) * PROTECTED_MODE_BASE_VECTOR_MASTER);
Private->BiosUnexpectedInt = BaseVectorMaster[0];
IntRedirCode = (UINT32) (UINTN) Private->IntThunk->InterruptRedirectionCode;
for (Index = 0; Index < 8; Index++) {
BaseVectorMaster[Index] = (EFI_SEGMENT (IntRedirCode + Index * 4) << 16) | EFI_OFFSET (IntRedirCode + Index * 4);
}
EnableNullDetection ();
//
// Save EFI value
//
@@ -1133,6 +1271,20 @@ LegacyBiosInstall (
);
ASSERT_EFI_ERROR (Status);
//
// Create callback to update status of EndOfDxe, which is needed by NULL
// pointer detection
//
Status = gBS->CreateEventEx (
EVT_NOTIFY_SIGNAL,
TPL_NOTIFY,
ToggleEndOfDxeStatus,
NULL,
&gEfiEndOfDxeEventGroupGuid,
&EndOfDxeEvent
);
ASSERT_EFI_ERROR (Status);
//
// Make a new handle and install the protocol
//