From: Peicong Li lipeicong@huawei.com
Flash region needs to be set as cacheable (write back) to increase performance, if PEI is still XIP on flash or DXE FV is decompressed from flash FV. However some ARM platforms do not support to set flash as inner shareable since flash is not normal DDR memory and it will not respond to cache snoop request, which will causes system hang after MMU is enabled.
So we need a new ARM memory region attribute WRITE_BACK_NONSHAREABLE for flash region on these platforms specifically. This attribute will set the region as write back but not inner shared.
Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Peicong Li lipeicong@huawei.com Signed-off-by: Heyi Guo heyi.guo@linaro.org Cc: Leif Lindholm leif.lindholm@linaro.org Cc: Ard Biesheuvel ard.biesheuvel@linaro.org --- ArmPkg/Include/Library/ArmLib.h | 7 +++++++ ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c | 4 ++++ 2 files changed, 11 insertions(+)
diff --git a/ArmPkg/Include/Library/ArmLib.h b/ArmPkg/Include/Library/ArmLib.h index 24ffe9f..38199be 100644 --- a/ArmPkg/Include/Library/ArmLib.h +++ b/ArmPkg/Include/Library/ArmLib.h @@ -41,6 +41,13 @@ typedef enum { ARM_MEMORY_REGION_ATTRIBUTE_NONSECURE_UNCACHED_UNBUFFERED, ARM_MEMORY_REGION_ATTRIBUTE_WRITE_BACK, ARM_MEMORY_REGION_ATTRIBUTE_NONSECURE_WRITE_BACK, + // On some platforms, memory mapped flash region is designed as not supporting + // shareable attribute, so WRITE_BACK_NONSHAREABLE is added for such special + // need. + // Do NOT use below two attributes if you are not sure. + ARM_MEMORY_REGION_ATTRIBUTE_WRITE_BACK_NONSHAREABLE, + ARM_MEMORY_REGION_ATTRIBUTE_NONSECURE_WRITE_BACK_NONSHAREABLE, + ARM_MEMORY_REGION_ATTRIBUTE_WRITE_THROUGH, ARM_MEMORY_REGION_ATTRIBUTE_NONSECURE_WRITE_THROUGH, ARM_MEMORY_REGION_ATTRIBUTE_DEVICE, diff --git a/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c b/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c index 8bd1c6f..4b62ecb 100644 --- a/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c +++ b/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c @@ -35,6 +35,10 @@ ArmMemoryAttributeToPageAttribute ( ) { switch (Attributes) { + case ARM_MEMORY_REGION_ATTRIBUTE_WRITE_BACK_NONSHAREABLE: + case ARM_MEMORY_REGION_ATTRIBUTE_NONSECURE_WRITE_BACK_NONSHAREABLE: + return TT_ATTR_INDX_MEMORY_WRITE_BACK; + case ARM_MEMORY_REGION_ATTRIBUTE_WRITE_BACK: case ARM_MEMORY_REGION_ATTRIBUTE_NONSECURE_WRITE_BACK: return TT_ATTR_INDX_MEMORY_WRITE_BACK | TT_SH_INNER_SHAREABLE;