diff mbox

[Linaro-uefi,1/2] Platforms/AMD: remove EFI_MEMORY_UC attribute from normal memory

Message ID 1473328166-18228-1-git-send-email-ard.biesheuvel@linaro.org
State Accepted
Commit 96f3bc2d596635f551308c703f7bb685c41fdce1
Headers show

Commit Message

Ard Biesheuvel Sept. 8, 2016, 9:49 a.m. UTC 
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(-)
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Patch

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 |