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    Subject[RFC V3 07/13] arm64/mm: Add FEAT_LPA2 specific encoding
    Date
    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@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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