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Date: Wed, 14 Jul 2021 07:51:26 +0530
From: Anshuman Khandual <anshuman.khandual@....com>
To: linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
linux-mm@...ck.org
Cc: akpm@...ux-foundation.org, suzuki.poulose@....com,
mark.rutland@....com, will@...nel.org, catalin.marinas@....com,
maz@...nel.org, james.morse@....com, steven.price@....com,
Anshuman Khandual <anshuman.khandual@....com>
Subject: [RFC 05/10] arm64/mm: Add CONFIG_ARM64_PA_BITS_52_[LPA|LPA2]
Going forward, CONFIG_ARM64_PA_BITS_52 could be enabled on a system via two
different architecture features i.e FEAT_LPA for CONFIG_ARM64_64K_PAGES and
FEAT_LPA2 for CONFIG_ARM64_[4K|16K]_PAGES. But CONFIG_ARM64_PA_BITS_52 is
exclussively available on 64K page size config currently, which needs to be
freed up for other page size configs to use when FEAT_LPA2 gets enabled.
To achieve CONFIG_ARM64_PA_BITS_52 and CONFIG_ARM64_64K_PAGES decoupling,
and also to reduce #ifdefs while navigating various page size configs, this
adds two internal config options CONFIG_ARM64_PA_BITS_52_[LPA|LPA2]. While
here it also converts existing 64K page size based FEAT_LPA implementations
to use CONFIG_ARM64_PA_BITS_52_LPA. TTBR representation remains same for
both FEAT_LPA and FEAT_LPA2. No functional change for 64K page size config.
Signed-off-by: Anshuman Khandual <anshuman.khandual@....com>
---
arch/arm64/Kconfig | 7 +++++++
arch/arm64/include/asm/assembler.h | 12 ++++++------
arch/arm64/include/asm/pgtable-hwdef.h | 7 ++++---
arch/arm64/include/asm/pgtable.h | 6 +++---
arch/arm64/mm/pgd.c | 2 +-
5 files changed, 21 insertions(+), 13 deletions(-)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index e07e7de..658a6fd 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -934,6 +934,12 @@ config ARM64_VA_BITS
default 48 if ARM64_VA_BITS_48
default 52 if ARM64_VA_BITS_52
+config ARM64_PA_BITS_52_LPA
+ bool
+
+config ARM64_PA_BITS_52_LPA2
+ bool
+
choice
prompt "Physical address space size"
default ARM64_PA_BITS_48
@@ -948,6 +954,7 @@ config ARM64_PA_BITS_52
bool "52-bit (ARMv8.2)"
depends on ARM64_64K_PAGES
depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
+ select ARM64_PA_BITS_52_LPA if ARM64_64K_PAGES
help
Enable support for a 52-bit physical address space, introduced as
part of the ARMv8.2-LPA extension.
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index 89faca0..fedc202 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -607,26 +607,26 @@ alternative_endif
.endm
.macro phys_to_pte, pte, phys
-#ifdef CONFIG_ARM64_PA_BITS_52
+#ifdef CONFIG_ARM64_PA_BITS_52_LPA
/*
* We assume \phys is 64K aligned and this is guaranteed by only
* supporting this configuration with 64K pages.
*/
orr \pte, \phys, \phys, lsr #36
and \pte, \pte, #PTE_ADDR_MASK
-#else
+#else /* !CONFIG_ARM64_PA_BITS_52_LPA */
mov \pte, \phys
-#endif
+#endif /* CONFIG_ARM64_PA_BITS_52_LPA */
.endm
.macro pte_to_phys, phys, pte
-#ifdef CONFIG_ARM64_PA_BITS_52
+#ifdef CONFIG_ARM64_PA_BITS_52_LPA
ubfiz \phys, \pte, #(48 - 16 - 12), #16
bfxil \phys, \pte, #16, #32
lsl \phys, \phys, #16
-#else
+#else /* !CONFIG_ARM64_PA_BITS_52_LPA */
and \phys, \pte, #PTE_ADDR_MASK
-#endif
+#endif /* CONFIG_ARM64_PA_BITS_52_LPA */
.endm
/*
diff --git a/arch/arm64/include/asm/pgtable-hwdef.h b/arch/arm64/include/asm/pgtable-hwdef.h
index 1eb5574..f375bcf 100644
--- a/arch/arm64/include/asm/pgtable-hwdef.h
+++ b/arch/arm64/include/asm/pgtable-hwdef.h
@@ -155,13 +155,14 @@
#define PTE_PXN (_AT(pteval_t, 1) << 53) /* Privileged XN */
#define PTE_UXN (_AT(pteval_t, 1) << 54) /* User XN */
+#ifdef CONFIG_ARM64_PA_BITS_52_LPA
#define PTE_ADDR_LOW (((_AT(pteval_t, 1) << (48 - PAGE_SHIFT)) - 1) << PAGE_SHIFT)
-#ifdef CONFIG_ARM64_PA_BITS_52
#define PTE_ADDR_HIGH (_AT(pteval_t, 0xf) << 12)
#define PTE_ADDR_MASK (PTE_ADDR_LOW | PTE_ADDR_HIGH)
-#else
+#else /* !CONFIG_ARM64_PA_BITS_52_LPA */
+#define PTE_ADDR_LOW (((_AT(pteval_t, 1) << (48 - PAGE_SHIFT)) - 1) << PAGE_SHIFT)
#define PTE_ADDR_MASK PTE_ADDR_LOW
-#endif
+#endif /* CONFIG_ARM64_PA_BITS_52_LPA */
/*
* AttrIndx[2:0] encoding (mapping attributes defined in the MAIR* registers).
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index f09bf5c..3c57fb2 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -66,14 +66,14 @@ extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
* Macros to convert between a physical address and its placement in a
* page table entry, taking care of 52-bit addresses.
*/
-#ifdef CONFIG_ARM64_PA_BITS_52
+#ifdef CONFIG_ARM64_PA_BITS_52_LPA
#define __pte_to_phys(pte) \
((pte_val(pte) & PTE_ADDR_LOW) | ((pte_val(pte) & PTE_ADDR_HIGH) << 36))
#define __phys_to_pte_val(phys) (((phys) | ((phys) >> 36)) & PTE_ADDR_MASK)
-#else
+#else /* !CONFIG_ARM64_PA_BITS_52_LPA */
#define __pte_to_phys(pte) (pte_val(pte) & PTE_ADDR_MASK)
#define __phys_to_pte_val(phys) (phys)
-#endif
+#endif /* CONFIG_ARM64_PA_BITS_52_LPA */
#define pte_pfn(pte) (__pte_to_phys(pte) >> PAGE_SHIFT)
#define pfn_pte(pfn,prot) \
diff --git a/arch/arm64/mm/pgd.c b/arch/arm64/mm/pgd.c
index 4a64089..090dfbe 100644
--- a/arch/arm64/mm/pgd.c
+++ b/arch/arm64/mm/pgd.c
@@ -40,7 +40,7 @@ void __init pgtable_cache_init(void)
if (PGD_SIZE == PAGE_SIZE)
return;
-#ifdef CONFIG_ARM64_PA_BITS_52
+#ifdef CONFIG_ARM64_PA_BITS_52_LPA
/*
* With 52-bit physical addresses, the architecture requires the
* top-level table to be aligned to at least 64 bytes.
--
2.7.4
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