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    Subject[PATCH 08/12] riscv: Fix accessing pfn bits in PTEs for non-32bit variants
    Date
    On rv32 the PFN part of PTEs is defined to use bits [xlen-1:10]
    while on rv64 it is defined to use bits [53:10], leaving [63:54]
    as reserved.

    With upcoming optional extensions like svpbmt these previously
    reserved bits will get used so simply right-shifting the PTE
    to get the PFN won't be enough.

    So introduce a _PAGE_PFN_MASK constant to mask the correct bits
    for both rv32 and rv64 before shifting.

    Signed-off-by: Heiko Stuebner <heiko@sntech.de>
    Reviewed-by: Philipp Tomsich <philipp.tomsich@vrull.eu>
    ---
    arch/riscv/include/asm/pgtable-32.h | 8 ++++++++
    arch/riscv/include/asm/pgtable-64.h | 14 +++++++++++---
    arch/riscv/include/asm/pgtable-bits.h | 6 ------
    arch/riscv/include/asm/pgtable.h | 8 +++++---
    4 files changed, 24 insertions(+), 12 deletions(-)

    diff --git a/arch/riscv/include/asm/pgtable-32.h b/arch/riscv/include/asm/pgtable-32.h
    index 5b2e79e5bfa5..e266a4fe7f43 100644
    --- a/arch/riscv/include/asm/pgtable-32.h
    +++ b/arch/riscv/include/asm/pgtable-32.h
    @@ -7,6 +7,7 @@
    #define _ASM_RISCV_PGTABLE_32_H

    #include <asm-generic/pgtable-nopmd.h>
    +#include <linux/bits.h>
    #include <linux/const.h>

    /* Size of region mapped by a page global directory */
    @@ -16,4 +17,11 @@

    #define MAX_POSSIBLE_PHYSMEM_BITS 34

    +/*
    + * rv32 PTE format:
    + * | XLEN-1 10 | 9 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
    + * PFN reserved for SW D A G U X W R V
    + */
    +#define _PAGE_PFN_MASK GENMASK(31, 10)
    +
    #endif /* _ASM_RISCV_PGTABLE_32_H */
    diff --git a/arch/riscv/include/asm/pgtable-64.h b/arch/riscv/include/asm/pgtable-64.h
    index 7e246e9f8d70..15f3ad5aee4f 100644
    --- a/arch/riscv/include/asm/pgtable-64.h
    +++ b/arch/riscv/include/asm/pgtable-64.h
    @@ -6,6 +6,7 @@
    #ifndef _ASM_RISCV_PGTABLE_64_H
    #define _ASM_RISCV_PGTABLE_64_H

    +#include <linux/bits.h>
    #include <linux/const.h>

    extern bool pgtable_l4_enabled;
    @@ -65,6 +66,13 @@ typedef struct {

    #define PTRS_PER_PMD (PAGE_SIZE / sizeof(pmd_t))

    +/*
    + * rv64 PTE format:
    + * | 63 | 62 61 | 60 54 | 53 10 | 9 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
    + * N MT RSV PFN reserved for SW D A G U X W R V
    + */
    +#define _PAGE_PFN_MASK GENMASK(53, 10)
    +
    static inline int pud_present(pud_t pud)
    {
    return (pud_val(pud) & _PAGE_PRESENT);
    @@ -108,12 +116,12 @@ static inline unsigned long _pud_pfn(pud_t pud)

    static inline pmd_t *pud_pgtable(pud_t pud)
    {
    - return (pmd_t *)pfn_to_virt(pud_val(pud) >> _PAGE_PFN_SHIFT);
    + return (pmd_t *)pfn_to_virt(__page_val_to_pfn(pud_val(pud)));
    }

    static inline struct page *pud_page(pud_t pud)
    {
    - return pfn_to_page(pud_val(pud) >> _PAGE_PFN_SHIFT);
    + return pfn_to_page(__page_val_to_pfn(pud_val(pud)));
    }

    #define mm_p4d_folded mm_p4d_folded
    @@ -143,7 +151,7 @@ static inline pmd_t pfn_pmd(unsigned long pfn, pgprot_t prot)

    static inline unsigned long _pmd_pfn(pmd_t pmd)
    {
    - return pmd_val(pmd) >> _PAGE_PFN_SHIFT;
    + return __page_val_to_pfn(pmd_val(pmd));
    }

    #define mk_pmd(page, prot) pfn_pmd(page_to_pfn(page), prot)
    diff --git a/arch/riscv/include/asm/pgtable-bits.h b/arch/riscv/include/asm/pgtable-bits.h
    index a6b0c89824c2..e571fa954afc 100644
    --- a/arch/riscv/include/asm/pgtable-bits.h
    +++ b/arch/riscv/include/asm/pgtable-bits.h
    @@ -6,12 +6,6 @@
    #ifndef _ASM_RISCV_PGTABLE_BITS_H
    #define _ASM_RISCV_PGTABLE_BITS_H

    -/*
    - * PTE format:
    - * | XLEN-1 10 | 9 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
    - * PFN reserved for SW D A G U X W R V
    - */
    -
    #define _PAGE_ACCESSED_OFFSET 6

    #define _PAGE_PRESENT (1 << 0)
    diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
    index 046b44225623..faba543e2b08 100644
    --- a/arch/riscv/include/asm/pgtable.h
    +++ b/arch/riscv/include/asm/pgtable.h
    @@ -108,6 +108,8 @@
    #include <asm/tlbflush.h>
    #include <linux/mm_types.h>

    +#define __page_val_to_pfn(_val) (((_val) & _PAGE_PFN_MASK) >> _PAGE_PFN_SHIFT)
    +
    #ifdef CONFIG_64BIT
    #include <asm/pgtable-64.h>
    #else
    @@ -261,12 +263,12 @@ static inline unsigned long _pgd_pfn(pgd_t pgd)

    static inline struct page *pmd_page(pmd_t pmd)
    {
    - return pfn_to_page(pmd_val(pmd) >> _PAGE_PFN_SHIFT);
    + return pfn_to_page(__page_val_to_pfn(pmd_val(pmd)));
    }

    static inline unsigned long pmd_page_vaddr(pmd_t pmd)
    {
    - return (unsigned long)pfn_to_virt(pmd_val(pmd) >> _PAGE_PFN_SHIFT);
    + return (unsigned long)pfn_to_virt(__page_val_to_pfn(pmd_val(pmd)));
    }

    static inline pte_t pmd_pte(pmd_t pmd)
    @@ -282,7 +284,7 @@ static inline pte_t pud_pte(pud_t pud)
    /* Yields the page frame number (PFN) of a page table entry */
    static inline unsigned long pte_pfn(pte_t pte)
    {
    - return (pte_val(pte) >> _PAGE_PFN_SHIFT);
    + return __page_val_to_pfn(pte_val(pte));
    }

    #define pte_page(x) pfn_to_page(pte_pfn(x))
    --
    2.35.1
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