tyler.durden
/
audk
mirror of https://github.com/acidanthera/audk.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

ArmPkg/ArmMmuLib: Extend API to manage memory permissions better 

Currently, ArmSetMemoryAttributes () takes a combination of
EFI_MEMORY_xx constants describing the memory type and permission
attributes that should be set on a region of memory. In cases where the
memory type is omitted, we assume that the memory permissions being set
are final, and that existing memory permissions can be discarded.

This is problematic, because we aim to map memory non-executable
(EFI_MEMORY_XP) by default, and only relax this requirement for code
regions that are mapped read-only (EFI_MEMORY_RO). Currently, setting
one permission clears the other, and so code managing these permissions
has to be aware of the existing permissions in order to be able to
preserve them, and this is not always tractable (e.g., the UEFI memory
attribute protocol implements an abstraction that promises to preserve
memory permissions that it is not operating on explicitly).

So let's add an AttributeMask parameter to ArmSetMemoryAttributes(),
which is permitted to be non-zero if no memory type is being provided,
in which case only memory permission attributes covered in the mask will
be affected by the update.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Oliver Smith-Denny <osde@linux.microsoft.com>
Reviewed-by: Michael Kubacki <michael.kubacki@microsoft.com>
This commit is contained in:
Ard Biesheuvel 2023-06-02 17:17:36 +02:00 committed by mergify[bot]
parent 9df2c0a555
commit 8f5ad634ad
5 changed files with 165 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
ArmPkg/Drivers/CpuDxe/CpuMmuCommon.c
View File

@ -217,7 +217,7 @@ CpuSetMemoryAttributes (
if (EFI_ERROR (Status) || (RegionArmAttributes != ArmAttributes) ||
((BaseAddress + Length) > (RegionBaseAddress + RegionLength)))
{
return ArmSetMemoryAttributes (BaseAddress, Length, EfiAttributes);
return ArmSetMemoryAttributes (BaseAddress, Length, EfiAttributes, 0);
} else {
return EFI_SUCCESS;
}

36
ArmPkg/Include/Library/ArmMmuLib.h
View File

@ -92,11 +92,45 @@ ArmReplaceLiveTranslationEntry (
IN BOOLEAN DisableMmu
);
/**
Set the requested memory permission attributes on a region of memory.
BaseAddress and Length must be aligned to EFI_PAGE_SIZE.
If Attributes contains a memory type attribute (EFI_MEMORY_UC/WC/WT/WB), the
region is mapped according to this memory type, and additional memory
permission attributes (EFI_MEMORY_RP/RO/XP) are taken into account as well,
discarding any permission attributes that are currently set for the region.
AttributeMask is ignored in this case, and must be set to 0x0.
If Attributes contains only a combination of memory permission attributes
(EFI_MEMORY_RP/RO/XP), each page in the region will retain its existing
memory type, even if it is not uniformly set across the region. In this case,
AttributesMask may be set to a mask of permission attributes, and memory
permissions omitted from this mask will not be updated for any page in the
region. All attributes appearing in Attributes must appear in AttributeMask
as well. (Attributes & ~AttributeMask must produce 0x0)
@param[in] BaseAddress The physical address that is the start address of
a memory region.
@param[in] Length The size in bytes of the memory region.
@param[in] Attributes Mask of memory attributes to set.
@param[in] AttributeMask Mask of memory attributes to take into account.
@retval EFI_SUCCESS The attributes were set for the memory region.
@retval EFI_INVALID_PARAMETER BaseAddress or Length is not suitably aligned.
Invalid combination of Attributes and
AttributeMask.
@retval EFI_OUT_OF_RESOURCES Requested attributes cannot be applied due to
lack of system resources.
**/
EFI_STATUS
ArmSetMemoryAttributes (
IN EFI_PHYSICAL_ADDRESS BaseAddress,
IN UINT64 Length,
IN UINT64 Attributes
IN UINT64 Attributes,
IN UINT64 AttributeMask
);
#endif // ARM_MMU_LIB_H_

52
ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
View File

@ -469,11 +469,45 @@ GcdAttributeToPageAttribute (
return PageAttributes;
}
/**
Set the requested memory permission attributes on a region of memory.
BaseAddress and Length must be aligned to EFI_PAGE_SIZE.
If Attributes contains a memory type attribute (EFI_MEMORY_UC/WC/WT/WB), the
region is mapped according to this memory type, and additional memory
permission attributes (EFI_MEMORY_RP/RO/XP) are taken into account as well,
discarding any permission attributes that are currently set for the region.
AttributeMask is ignored in this case, and must be set to 0x0.
If Attributes contains only a combination of memory permission attributes
(EFI_MEMORY_RP/RO/XP), each page in the region will retain its existing
memory type, even if it is not uniformly set across the region. In this case,
AttributesMask may be set to a mask of permission attributes, and memory
permissions omitted from this mask will not be updated for any page in the
region. All attributes appearing in Attributes must appear in AttributeMask
as well. (Attributes & ~AttributeMask must produce 0x0)
@param[in] BaseAddress The physical address that is the start address of
a memory region.
@param[in] Length The size in bytes of the memory region.
@param[in] Attributes Mask of memory attributes to set.
@param[in] AttributeMask Mask of memory attributes to take into account.
@retval EFI_SUCCESS The attributes were set for the memory region.
@retval EFI_INVALID_PARAMETER BaseAddress or Length is not suitably aligned.
Invalid combination of Attributes and
AttributeMask.
@retval EFI_OUT_OF_RESOURCES Requested attributes cannot be applied due to
lack of system resources.
**/
EFI_STATUS
ArmSetMemoryAttributes (
IN EFI_PHYSICAL_ADDRESS BaseAddress,
IN UINT64 Length,
IN UINT64 Attributes
IN UINT64 Attributes,
IN UINT64 AttributeMask
)
{
UINT64 PageAttributes;
@ -490,6 +524,22 @@ ArmSetMemoryAttributes (
PageAttributes &= TT_AP_MASK | TT_UXN_MASK | TT_PXN_MASK | TT_AF;
PageAttributeMask = ~(TT_ADDRESS_MASK_BLOCK_ENTRY | TT_AP_MASK |
TT_PXN_MASK | TT_XN_MASK | TT_AF);
if (AttributeMask != 0) {
if (((AttributeMask & ~(UINT64)(EFI_MEMORY_RP|EFI_MEMORY_RO|EFI_MEMORY_XP)) != 0) ||
((Attributes & ~AttributeMask) != 0))
{
return EFI_INVALID_PARAMETER;
}
// Add attributes omitted from AttributeMask to the set of attributes to preserve
PageAttributeMask |= GcdAttributeToPageAttribute (~AttributeMask) &
(TT_AP_MASK | TT_UXN_MASK | TT_PXN_MASK | TT_AF);
}
} else {
ASSERT (AttributeMask == 0);
if (AttributeMask != 0) {
return EFI_INVALID_PARAMETER;
}
}
return UpdateRegionMapping (

88
ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibUpdate.c
View File

@ -10,6 +10,7 @@
#include <Uefi.h>
#include <Library/ArmLib.h>
#include <Library/ArmMmuLib.h>
#include <Library/BaseLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/DebugLib.h>
@ -451,31 +452,96 @@ SetMemoryAttributes (
}
/**
Update the permission or memory type attributes on a range of memory.
Set the requested memory permission attributes on a region of memory.
@param BaseAddress The start of the region.
@param Length The size of the region.
@param Attributes A mask of EFI_MEMORY_xx constants.
BaseAddress and Length must be aligned to EFI_PAGE_SIZE.
@retval EFI_SUCCESS The attributes were set successfully.
@retval EFI_OUT_OF_RESOURCES The operation failed due to insufficient memory.
If Attributes contains a memory type attribute (EFI_MEMORY_UC/WC/WT/WB), the
region is mapped according to this memory type, and additional memory
permission attributes (EFI_MEMORY_RP/RO/XP) are taken into account as well,
discarding any permission attributes that are currently set for the region.
AttributeMask is ignored in this case, and must be set to 0x0.
If Attributes contains only a combination of memory permission attributes
(EFI_MEMORY_RP/RO/XP), each page in the region will retain its existing
memory type, even if it is not uniformly set across the region. In this case,
AttributesMask may be set to a mask of permission attributes, and memory
permissions omitted from this mask will not be updated for any page in the
region. All attributes appearing in Attributes must appear in AttributeMask
as well. (Attributes & ~AttributeMask must produce 0x0)
@param[in] BaseAddress The physical address that is the start address of
a memory region.
@param[in] Length The size in bytes of the memory region.
@param[in] Attributes Mask of memory attributes to set.
@param[in] AttributeMask Mask of memory attributes to take into account.
@retval EFI_SUCCESS The attributes were set for the memory region.
@retval EFI_INVALID_PARAMETER BaseAddress or Length is not suitably aligned.
Invalid combination of Attributes and
AttributeMask.
@retval EFI_OUT_OF_RESOURCES Requested attributes cannot be applied due to
lack of system resources.
**/
EFI_STATUS
ArmSetMemoryAttributes (
IN EFI_PHYSICAL_ADDRESS BaseAddress,
IN UINT64 Length,
IN UINT64 Attributes
IN UINT64 Attributes,
IN UINT64 AttributeMask
)
{
UINT32 TtEntryMask;
if (((BaseAddress | Length) & EFI_PAGE_MASK) != 0) {
return EFI_INVALID_PARAMETER;
}
if ((Attributes & EFI_MEMORY_CACHETYPE_MASK) == 0) {
//
// No memory type was set in Attributes, so we are going to update the
// permissions only.
//
if (AttributeMask != 0) {
if (((AttributeMask & ~(UINT64)(EFI_MEMORY_RP|EFI_MEMORY_RO|EFI_MEMORY_XP)) != 0) ||
((Attributes & ~AttributeMask) != 0))
{
return EFI_INVALID_PARAMETER;
}
} else {
AttributeMask = EFI_MEMORY_RP | EFI_MEMORY_RO | EFI_MEMORY_XP;
}
TtEntryMask = 0;
if ((AttributeMask & EFI_MEMORY_RP) != 0) {
TtEntryMask |= TT_DESCRIPTOR_SECTION_AF;
}
if ((AttributeMask & EFI_MEMORY_RO) != 0) {
TtEntryMask |= TT_DESCRIPTOR_SECTION_AP_MASK;
}
if ((AttributeMask & EFI_MEMORY_XP) != 0) {
TtEntryMask |= TT_DESCRIPTOR_SECTION_XN_MASK;
}
} else {
ASSERT (AttributeMask == 0);
if (AttributeMask != 0) {
return EFI_INVALID_PARAMETER;
}
TtEntryMask = TT_DESCRIPTOR_SECTION_TYPE_MASK |
TT_DESCRIPTOR_SECTION_XN_MASK |
TT_DESCRIPTOR_SECTION_AP_MASK |
TT_DESCRIPTOR_SECTION_AF;
}
return SetMemoryAttributes (
BaseAddress,
Length,
Attributes,
TT_DESCRIPTOR_SECTION_TYPE_MASK |
TT_DESCRIPTOR_SECTION_XN_MASK |
TT_DESCRIPTOR_SECTION_AP_MASK |
TT_DESCRIPTOR_SECTION_AF
TtEntryMask
);
}

2
ArmPkg/Library/OpteeLib/Optee.c
View File

@ -86,7 +86,7 @@ OpteeSharedMemoryRemap (
return EFI_BUFFER_TOO_SMALL;
}
Status = ArmSetMemoryAttributes (PhysicalAddress, Size, EFI_MEMORY_WB);
Status = ArmSetMemoryAttributes (PhysicalAddress, Size, EFI_MEMORY_WB, 0);
if (EFI_ERROR (Status)) {
return Status;
}