Re: [PATCH V7 3/5] arm64: mm: add PROT_DEVICE_nGnRnE and PROT_NORMAL_WT
From: Zhang, Jonathan Zhixiong
Date: Fri Jul 24 2015 - 15:02:57 EST
On 7/24/2015 9:15 AM, Catalin Marinas wrote:
On Tue, Jul 21, 2015 at 10:59:18PM +0100, Jonathan (Zhixiong) Zhang wrote:
From: "Jonathan (Zhixiong) Zhang" <zjzhang@xxxxxxxxxxxxxx>
UEFI spec 2.5 section 2.3.6.1 defines that EFI_MEMORY_[UC|WC|WT|WB] are
possible EFI memory types for AArch64. Each of those EFI memory types
is mapped to a corresponding AArch64 memory type. So we need to define
PROT_DEVICE_nGnRnE and PROT_NORMWL_WT.
MT_NORMAL_WT is defined, and its encoding is added to MAIR_EL1 when
initializing cpu.
Change-Id: I20ac71ddf74c17e41769ecbb5f8c60eeefbb398a
Signed-off-by: Jonathan (Zhixiong) Zhang <zjzhang@xxxxxxxxxxxxxx>
I'll let the EFI guys to comment on whether these are needed, what for
(we could probably live just fine only with Device nGnRE and Normal NC).
#define PROT_SECT_DEVICE_nGnRE (PROT_SECT_DEFAULT | PMD_SECT_PXN | PMD_SECT_UXN | PMD_ATTRINDX(MT_DEVICE_nGnRE))
diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
index 838266f5b056..23e265d732f8 100644
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S
@@ -294,7 +294,7 @@ ENTRY(__cpu_setup)
msr cpacr_el1, x0 // Enable FP/ASIMD
msr mdscr_el1, xzr // Reset mdscr_el1
/*
- * Memory region attributes for LPAE:
+ * Memory region attributes for LPAE and EFI:
LPAE refers to the page table format, the comment probably inherited
from arch/arm. EFI means a completely different thing, so please remove
it.
Yes, it was inherited from arch/arm/mm/proc-v7-3level.S. I'll remove
the change. That being said, the original statement is not totally
accurate I think, so if you prefer, I could change it like following.
- * Memory region attributes for LPAE:
+ * Set MAIR with memory region attributes:
--
Jonathan (Zhixiong) Zhang
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
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