[RFC V3 07/13] arm64/mm: Add FEAT_LPA2 specific encoding
Anshuman Khandual
anshuman.khandual at arm.com
Thu Sep 30 03:35:10 PDT 2021
FEAT_LPA2 requires different PTE representation formats for both 4K and 16K
page size config. This adds FEAT_LPA2 specific new PTE encodings as per ARM
ARM (0487G.A) which updates [pte|phys]_to_[phys|pte](). The updated helpers
would be used when FEAT_LPA2 gets enabled via CONFIG_ARM64_PA_BITS_52 on 4K
and 16K page size. Although TTBR encoding and phys_to_ttbr() helper remains
the same as FEAT_LPA for FEAT_LPA2 as well. It updates 'phys_to_pte' helper
to accept a temporary variable and changes impacted call sites.
Signed-off-by: Anshuman Khandual <anshuman.khandual at arm.com>
---
arch/arm64/include/asm/assembler.h | 14 +++++++++++---
arch/arm64/include/asm/pgtable-hwdef.h | 4 ++++
arch/arm64/include/asm/pgtable.h | 4 ++++
3 files changed, 19 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index 3fbe04a..c1543067 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -628,6 +628,10 @@ alternative_endif
*/
orr \pte, \phys, \phys, lsr #36
and \pte, \pte, #PTE_ADDR_MASK
+#elif defined(CONFIG_ARM64_PA_BITS_52_LPA2)
+ orr \pte, \phys, \phys, lsr #42
+ and \pte, \pte, #PTE_ADDR_MASK | GENMASK(PAGE_SHIFT - 1, 10)
+ and \pte, \pte, #~GENMASK(PAGE_SHIFT - 1, 10)
#else /* !CONFIG_ARM64_PA_BITS_52_LPA */
mov \pte, \phys
#endif /* CONFIG_ARM64_PA_BITS_52_LPA */
@@ -635,9 +639,13 @@ alternative_endif
.macro pte_to_phys, phys, pte
#ifdef CONFIG_ARM64_PA_BITS_52_LPA
- ubfiz \phys, \pte, #(48 - 16 - 12), #16
- bfxil \phys, \pte, #16, #32
- lsl \phys, \phys, #16
+ ubfiz \phys, \pte, #(48 - PAGE_SHIFT - 12), #16
+ bfxil \phys, \pte, #PAGE_SHIFT, #(48 - PAGE_SHIFT)
+ lsl \phys, \phys, #PAGE_SHIFT
+#elif defined(CONFIG_ARM64_PA_BITS_52_LPA2)
+ ubfiz \phys, \pte, #(52 - PAGE_SHIFT - 10), #10
+ bfxil \phys, \pte, #PAGE_SHIFT, #(50 - PAGE_SHIFT)
+ lsl \phys, \phys, #PAGE_SHIFT
#else /* !CONFIG_ARM64_PA_BITS_52_LPA */
and \phys, \pte, #PTE_ADDR_MASK
#endif /* CONFIG_ARM64_PA_BITS_52_LPA */
diff --git a/arch/arm64/include/asm/pgtable-hwdef.h b/arch/arm64/include/asm/pgtable-hwdef.h
index f375bcf..c815a85 100644
--- a/arch/arm64/include/asm/pgtable-hwdef.h
+++ b/arch/arm64/include/asm/pgtable-hwdef.h
@@ -159,6 +159,10 @@
#define PTE_ADDR_LOW (((_AT(pteval_t, 1) << (48 - PAGE_SHIFT)) - 1) << PAGE_SHIFT)
#define PTE_ADDR_HIGH (_AT(pteval_t, 0xf) << 12)
#define PTE_ADDR_MASK (PTE_ADDR_LOW | PTE_ADDR_HIGH)
+#elif defined(CONFIG_ARM64_PA_BITS_52_LPA2)
+#define PTE_ADDR_LOW (((_AT(pteval_t, 1) << (50 - PAGE_SHIFT)) - 1) << PAGE_SHIFT)
+#define PTE_ADDR_HIGH (_AT(pteval_t, 0x3) << 8)
+#define PTE_ADDR_MASK (PTE_ADDR_LOW | PTE_ADDR_HIGH)
#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
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 09b081e..9038d05 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -70,6 +70,10 @@ extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
#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)
+#elif defined(CONFIG_ARM64_PA_BITS_52_LPA2)
+#define __pte_to_phys(pte) \
+ ((pte_val(pte) & PTE_ADDR_LOW) | ((pte_val(pte) & PTE_ADDR_HIGH) << 42))
+#define __phys_to_pte_val(phys) (((phys) | ((phys) >> 42)) & PTE_ADDR_MASK)
#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)
--
2.7.4
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