On ARM systems, mapping normal memory as device memory may have unintended side effects, given that unaligned accesses or loads and stores with special semantics (e.g., load/store exclusive) may fault or may not work as expected. Similarly, DC ZVA instructions are only supported on normal memory, not device memory.

So remove the EFI_MEMORY_UC attribute that we set by default on system RAM. If any region requires this attribute, it is up to the driver to set this attribute, and to ensure that no offending operations are performed on it.

Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Ard Biesheuvel ard.biesheuvel@linaro.org --- Platforms/AMD/Styx/Library/MemoryInitPei/MemoryInitPeiLib.c | 2 -- 1 file changed, 2 deletions(-)

diff --git a/Platforms/AMD/Styx/Library/MemoryInitPei/MemoryInitPeiLib.c b/Platforms/AMD/Styx/Library/MemoryInitPei/MemoryInitPeiLib.c index 5fb63349864e..70821d1b120b 100644 --- a/Platforms/AMD/Styx/Library/MemoryInitPei/MemoryInitPeiLib.c +++ b/Platforms/AMD/Styx/Library/MemoryInitPei/MemoryInitPeiLib.c @@ -143,7 +143,6 @@ MemoryPeim ( EFI_RESOURCE_SYSTEM_MEMORY, ( EFI_RESOURCE_ATTRIBUTE_PRESENT | EFI_RESOURCE_ATTRIBUTE_INITIALIZED | - EFI_RESOURCE_ATTRIBUTE_UNCACHEABLE | EFI_RESOURCE_ATTRIBUTE_WRITE_COMBINEABLE | EFI_RESOURCE_ATTRIBUTE_WRITE_THROUGH_CACHEABLE | EFI_RESOURCE_ATTRIBUTE_WRITE_BACK_CACHEABLE | @@ -164,7 +163,6 @@ MemoryPeim ( EFI_RESOURCE_SYSTEM_MEMORY, ( EFI_RESOURCE_ATTRIBUTE_PRESENT | EFI_RESOURCE_ATTRIBUTE_INITIALIZED | - EFI_RESOURCE_ATTRIBUTE_UNCACHEABLE | EFI_RESOURCE_ATTRIBUTE_WRITE_COMBINEABLE | EFI_RESOURCE_ATTRIBUTE_WRITE_THROUGH_CACHEABLE | EFI_RESOURCE_ATTRIBUTE_WRITE_BACK_CACHEABLE |