ArmPkg/CpuDxe ARM: Fix page-to-section attribute conversion

The section-to-page attribute conversion takes the shareability and
execute-never attributes into account, whereas the page-to-section
counterpart does not. The result is that GetMemoryRegionPage () -which
takes a section attribute argument (via *RegionAttributes) that is
ostensibly based on the first page in the range, but differs from the
actual page attributes when converted back- may return with a
RegionLength of zero. This is incorrect, and confuses code that scans a
region by calling GetMemoryRegion () in sequence.

So fix the conversion, and ASSERT () on a non-zero region length.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Leif Lindholm <quic_llindhol@quicinc.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/ArmPkg/Include/Chipset/ArmV7Mmu.h b/ArmPkg/Include/Chipset/ArmV7Mmu.h
index 6a2584ceb3..e0219747df 100644
--- a/ArmPkg/Include/Chipset/ArmV7Mmu.h
+++ b/ArmPkg/Include/Chipset/ArmV7Mmu.h
@@ -128,6 +128,8 @@
 #define TT_DESCRIPTOR_CONVERT_TO_PAGE_CACHE_POLICY(Desc)  ((((Desc) & (0x3 << 12)) >> 6) | (Desc & (0x3 << 2)))

 

 #define TT_DESCRIPTOR_CONVERT_TO_SECTION_AP(Desc)            ((((Desc) & TT_DESCRIPTOR_PAGE_AP_MASK) << 6) & TT_DESCRIPTOR_SECTION_AP_MASK)

+#define TT_DESCRIPTOR_CONVERT_TO_SECTION_S(Desc)             ((((Desc) & TT_DESCRIPTOR_PAGE_S_MASK) << 6) & TT_DESCRIPTOR_SECTION_S_MASK)

+#define TT_DESCRIPTOR_CONVERT_TO_SECTION_XN(Desc)            ((((Desc) & TT_DESCRIPTOR_PAGE_XN_MASK) << 4) & TT_DESCRIPTOR_SECTION_XN_MASK)

 #define TT_DESCRIPTOR_CONVERT_TO_SECTION_CACHE_POLICY(Desc)  ((((Desc) & (0x3 << 6)) << 6) | (Desc & (0x3 << 2)))

 

 #define TT_DESCRIPTOR_SECTION_ATTRIBUTE_MASK  (TT_DESCRIPTOR_SECTION_NS_MASK | TT_DESCRIPTOR_SECTION_NG_MASK |               \