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ArmPkg/ArmMmuLib: Introduce region types for RO/XP WB cached memory 

To prepare for the enablement of booting EFI with the SCTLR.WXN control
enabled, which makes all writeable memory regions non-executable by
default, introduce a memory type that we will use to describe the flash
region that carries the SEC and PEIM modules that execute in place. Even
if these are implicitly read-only due to the ROM nature, they need to be
mapped with read-only attributes in the page tables to be able to
execute from them.

Also add the XP counterpart which will be used for all normal DRAM right
at the outset.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Leif Lindholm <quic_llindhol@quicinc.com>
This commit is contained in:
Ard Biesheuvel 2023-02-10 17:52:45 +01:00 committed by mergify[bot]
parent 852227a9d5
commit b05523a4e9
3 changed files with 47 additions and 6 deletions
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6
ArmPkg/Include/Library/ArmLib.h
View File

@ -35,6 +35,12 @@ typedef enum {
// Do NOT use below two attributes if you are not sure.
ARM_MEMORY_REGION_ATTRIBUTE_WRITE_BACK_NONSHAREABLE,
// Special region types for memory that must be mapped with read-only or
// non-execute permissions from the very start, e.g., to support the use
// of the WXN virtual memory control.
ARM_MEMORY_REGION_ATTRIBUTE_WRITE_BACK_RO,
ARM_MEMORY_REGION_ATTRIBUTE_WRITE_BACK_XP,
ARM_MEMORY_REGION_ATTRIBUTE_WRITE_THROUGH,
ARM_MEMORY_REGION_ATTRIBUTE_DEVICE,
} ARM_MEMORY_REGION_ATTRIBUTES;

31
ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
View File

@ -37,12 +37,35 @@ ArmMemoryAttributeToPageAttribute (
IN ARM_MEMORY_REGION_ATTRIBUTES Attributes
)
{
UINT64 Permissions;
switch (Attributes) {
case ARM_MEMORY_REGION_ATTRIBUTE_WRITE_BACK_RO:
Permissions = TT_AP_NO_RO;
break;
case ARM_MEMORY_REGION_ATTRIBUTE_WRITE_BACK_XP:
case ARM_MEMORY_REGION_ATTRIBUTE_DEVICE:
if (ArmReadCurrentEL () == AARCH64_EL2) {
Permissions = TT_XN_MASK;
} else {
Permissions = TT_UXN_MASK | TT_PXN_MASK;
}
break;
default:
Permissions = 0;
break;
}
switch (Attributes) {
case ARM_MEMORY_REGION_ATTRIBUTE_WRITE_BACK_NONSHAREABLE:
return TT_ATTR_INDX_MEMORY_WRITE_BACK;
case ARM_MEMORY_REGION_ATTRIBUTE_WRITE_BACK:
return TT_ATTR_INDX_MEMORY_WRITE_BACK | TT_SH_INNER_SHAREABLE;
case ARM_MEMORY_REGION_ATTRIBUTE_WRITE_BACK_RO:
case ARM_MEMORY_REGION_ATTRIBUTE_WRITE_BACK_XP:
return TT_ATTR_INDX_MEMORY_WRITE_BACK | TT_SH_INNER_SHAREABLE | Permissions;
case ARM_MEMORY_REGION_ATTRIBUTE_WRITE_THROUGH:
return TT_ATTR_INDX_MEMORY_WRITE_THROUGH | TT_SH_INNER_SHAREABLE;
@ -54,11 +77,7 @@ ArmMemoryAttributeToPageAttribute (
default:
ASSERT (0);
case ARM_MEMORY_REGION_ATTRIBUTE_DEVICE:
if (ArmReadCurrentEL () == AARCH64_EL2) {
return TT_ATTR_INDX_DEVICE_MEMORY | TT_XN_MASK;
} else {
return TT_ATTR_INDX_DEVICE_MEMORY | TT_UXN_MASK | TT_PXN_MASK;
}
return TT_ATTR_INDX_DEVICE_MEMORY | Permissions;
}
}

16
ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibCore.c
View File

@ -106,6 +106,14 @@ PopulateLevel2PageTable (
PageAttributes = TT_DESCRIPTOR_PAGE_WRITE_BACK;
PageAttributes &= ~TT_DESCRIPTOR_PAGE_S_SHARED;
break;
case ARM_MEMORY_REGION_ATTRIBUTE_WRITE_BACK_RO:
PageAttributes = TT_DESCRIPTOR_PAGE_WRITE_BACK;
PageAttributes |= TT_DESCRIPTOR_PAGE_AP_NO_RO;
break;
case ARM_MEMORY_REGION_ATTRIBUTE_WRITE_BACK_XP:
PageAttributes = TT_DESCRIPTOR_PAGE_WRITE_BACK;
PageAttributes |= TT_DESCRIPTOR_PAGE_XN_MASK;
break;
case ARM_MEMORY_REGION_ATTRIBUTE_WRITE_THROUGH:
PageAttributes = TT_DESCRIPTOR_PAGE_WRITE_THROUGH;
break;
@ -240,6 +248,14 @@ FillTranslationTable (
Attributes = TT_DESCRIPTOR_SECTION_WRITE_BACK;
Attributes &= ~TT_DESCRIPTOR_SECTION_S_SHARED;
break;
case ARM_MEMORY_REGION_ATTRIBUTE_WRITE_BACK_RO:
Attributes = TT_DESCRIPTOR_SECTION_WRITE_BACK;
Attributes |= TT_DESCRIPTOR_SECTION_AP_NO_RO;
break;
case ARM_MEMORY_REGION_ATTRIBUTE_WRITE_BACK_XP:
Attributes = TT_DESCRIPTOR_SECTION_WRITE_BACK;
Attributes |= TT_DESCRIPTOR_SECTION_XN_MASK;
break;
case ARM_MEMORY_REGION_ATTRIBUTE_WRITE_THROUGH:
Attributes = TT_DESCRIPTOR_SECTION_WRITE_THROUGH;
break;