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    SubjectRe: [PATCH v2 03/17] arm64: Make page table helpers reusable
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    Hi Suzuki,

    On 27/03/18 14:15, Suzuki K Poulose wrote:
    > This patch rearranges the page table level helpers so that it can
    > be reused for a page table with different number of levels
    > (e.g, stage2 page table for a VM) than the kernel page tables.
    > As such there is no functional change with this patch.
    >
    > The page table helpers are defined to do the right thing for the
    > fixed page table levels set for the kernel. This patch tries to
    > refactor the code such that, we can have helpers for each level,
    > which should be used when the caller knows that the level exists
    > for the page table dealt with. Since the kernel defines helpers
    > p.d_action and __p.d_action, for consistency, we name the raw
    > page table action helpers __raw_p.d_action.
    >
    > Cc: Catalin Marinas <catalin.marinas@arm.com>
    > Cc: Mark Rutland <mark.rutland@arm.com>
    > Cc: Will Deacon <will.deacon@arm.com>
    > Cc: Steve Capper <steve.capper@arm.com>
    > Cc: Marc Zyngier <marc.zyngier@arm.com>
    > Cc: Christoffer Dall <cdall@kernel.org>
    > Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>

    Reviewed-by: Julien Grall <julien.grall@arm.com>

    Cheers,

    > ---
    > arch/arm64/include/asm/pgalloc.h | 34 +++++++++++++++++++----
    > arch/arm64/include/asm/pgtable.h | 60 +++++++++++++++++++++++++---------------
    > 2 files changed, 66 insertions(+), 28 deletions(-)
    >
    > diff --git a/arch/arm64/include/asm/pgalloc.h b/arch/arm64/include/asm/pgalloc.h
    > index 2e05bcd..ab4662c 100644
    > --- a/arch/arm64/include/asm/pgalloc.h
    > +++ b/arch/arm64/include/asm/pgalloc.h
    > @@ -29,6 +29,30 @@
    > #define PGALLOC_GFP (GFP_KERNEL | __GFP_ZERO)
    > #define PGD_SIZE (PTRS_PER_PGD * sizeof(pgd_t))
    >
    > +static inline void __raw_pmd_free(pmd_t *pmdp)
    > +{
    > + BUG_ON((unsigned long)pmdp & (PAGE_SIZE-1));
    > + free_page((unsigned long)pmdp);
    > +}
    > +
    > +static inline void
    > +__raw_pud_populate(pud_t *pudp, phys_addr_t pmdp, pudval_t prot)
    > +{
    > + __raw_set_pud(pudp, __pud(__phys_to_pud_val(pmdp) | prot));
    > +}
    > +
    > +static inline void __raw_pud_free(pud_t *pudp)
    > +{
    > + BUG_ON((unsigned long)pudp & (PAGE_SIZE-1));
    > + free_page((unsigned long)pudp);
    > +}
    > +
    > +static inline void
    > +__raw_pgd_populate(pgd_t *pgdp, phys_addr_t pudp, pgdval_t prot)
    > +{
    > + __raw_set_pgd(pgdp, __pgd(__phys_to_pgd_val(pudp) | prot));
    > +}
    > +
    > #if CONFIG_PGTABLE_LEVELS > 2
    >
    > static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
    > @@ -38,13 +62,12 @@ static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
    >
    > static inline void pmd_free(struct mm_struct *mm, pmd_t *pmdp)
    > {
    > - BUG_ON((unsigned long)pmdp & (PAGE_SIZE-1));
    > - free_page((unsigned long)pmdp);
    > + __raw_pmd_free(pmdp);
    > }
    >
    > static inline void __pud_populate(pud_t *pudp, phys_addr_t pmdp, pudval_t prot)
    > {
    > - set_pud(pudp, __pud(__phys_to_pud_val(pmdp) | prot));
    > + __raw_pud_populate(pudp, pmdp, prot);
    > }
    >
    > static inline void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmdp)
    > @@ -67,13 +90,12 @@ static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long addr)
    >
    > static inline void pud_free(struct mm_struct *mm, pud_t *pudp)
    > {
    > - BUG_ON((unsigned long)pudp & (PAGE_SIZE-1));
    > - free_page((unsigned long)pudp);
    > + __raw_pud_free(pudp);
    > }
    >
    > static inline void __pgd_populate(pgd_t *pgdp, phys_addr_t pudp, pgdval_t prot)
    > {
    > - set_pgd(pgdp, __pgd(__phys_to_pgd_val(pudp) | prot));
    > + __raw_pgd_populate(pgdp, pudp, prot);
    > }
    >
    > static inline void pgd_populate(struct mm_struct *mm, pgd_t *pgdp, pud_t *pudp)
    > diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
    > index 7e2c27e..5e22503 100644
    > --- a/arch/arm64/include/asm/pgtable.h
    > +++ b/arch/arm64/include/asm/pgtable.h
    > @@ -475,31 +475,39 @@ static inline phys_addr_t pmd_page_paddr(pmd_t pmd)
    > */
    > #define mk_pte(page,prot) pfn_pte(page_to_pfn(page),prot)
    >
    > -#if CONFIG_PGTABLE_LEVELS > 2
    > +#define __raw_pud_none(pud) (!pud_val(pud))
    > +#define __raw_pud_bad(pud) (!(pud_val(pud) & PUD_TABLE_BIT))
    > +#define __raw_pud_present(pud) pte_present(pud_pte(pud))
    >
    > -#define pmd_ERROR(pmd) __pmd_error(__FILE__, __LINE__, pmd_val(pmd))
    > -
    > -#define pud_none(pud) (!pud_val(pud))
    > -#define pud_bad(pud) (!(pud_val(pud) & PUD_TABLE_BIT))
    > -#define pud_present(pud) pte_present(pud_pte(pud))
    > -
    > -static inline void set_pud(pud_t *pudp, pud_t pud)
    > +static inline void __raw_set_pud(pud_t *pudp, pud_t pud)
    > {
    > WRITE_ONCE(*pudp, pud);
    > dsb(ishst);
    > isb();
    > }
    >
    > -static inline void pud_clear(pud_t *pudp)
    > +static inline void __raw_pud_clear(pud_t *pudp)
    > {
    > - set_pud(pudp, __pud(0));
    > + __raw_set_pud(pudp, __pud(0));
    > }
    >
    > -static inline phys_addr_t pud_page_paddr(pud_t pud)
    > +static inline phys_addr_t __raw_pud_page_paddr(pud_t pud)
    > {
    > return __pud_to_phys(pud);
    > }
    >
    > +#if CONFIG_PGTABLE_LEVELS > 2
    > +
    > +#define pmd_ERROR(pmd) __pmd_error(__FILE__, __LINE__, pmd_val(pmd))
    > +
    > +#define pud_none(pud) __raw_pud_none(pud)
    > +#define pud_bad(pud) __raw_pud_bad(pud)
    > +#define pud_present(pud) __raw_pud_present(pud)
    > +
    > +#define set_pud(pudp, pud) __raw_set_pud((pudp), (pud))
    > +#define pud_clear(pudp) __raw_pud_clear((pudp))
    > +#define pud_page_paddr(pud) __raw_pud_page_paddr((pud))
    > +
    > /* Find an entry in the second-level page table. */
    > #define pmd_index(addr) (((addr) >> PMD_SHIFT) & (PTRS_PER_PMD - 1))
    >
    > @@ -528,30 +536,38 @@ static inline phys_addr_t pud_page_paddr(pud_t pud)
    >
    > #endif /* CONFIG_PGTABLE_LEVELS > 2 */
    >
    > -#if CONFIG_PGTABLE_LEVELS > 3
    > +#define __raw_pgd_none(pgd) (!pgd_val(pgd))
    > +#define __raw_pgd_bad(pgd) (!(pgd_val(pgd) & 2))
    > +#define __raw_pgd_present(pgd) (pgd_val(pgd))
    >
    > -#define pud_ERROR(pud) __pud_error(__FILE__, __LINE__, pud_val(pud))
    > -
    > -#define pgd_none(pgd) (!pgd_val(pgd))
    > -#define pgd_bad(pgd) (!(pgd_val(pgd) & 2))
    > -#define pgd_present(pgd) (pgd_val(pgd))
    > -
    > -static inline void set_pgd(pgd_t *pgdp, pgd_t pgd)
    > +static inline void __raw_set_pgd(pgd_t *pgdp, pgd_t pgd)
    > {
    > WRITE_ONCE(*pgdp, pgd);
    > dsb(ishst);
    > }
    >
    > -static inline void pgd_clear(pgd_t *pgdp)
    > +static inline void __raw_pgd_clear(pgd_t *pgdp)
    > {
    > - set_pgd(pgdp, __pgd(0));
    > + __raw_set_pgd(pgdp, __pgd(0));
    > }
    >
    > -static inline phys_addr_t pgd_page_paddr(pgd_t pgd)
    > +static inline phys_addr_t __raw_pgd_page_paddr(pgd_t pgd)
    > {
    > return __pgd_to_phys(pgd);
    > }
    >
    > +#if CONFIG_PGTABLE_LEVELS > 3
    > +
    > +#define pud_ERROR(pud) __pud_error(__FILE__, __LINE__, pud_val(pud))
    > +
    > +#define pgd_none(pgd) __raw_pgd_none((pgd))
    > +#define pgd_bad(pgd) __raw_pgd_bad((pgd))
    > +#define pgd_present(pgd) __raw_pgd_present((pgd))
    > +
    > +#define set_pgd(pgdp, pgd) __raw_set_pgd((pgdp), (pgd))
    > +#define pgd_clear(pgdp) __raw_pgd_clear((pgdp))
    > +#define pgd_page_paddr(pgd) __raw_pgd_page_paddr((pgd))
    > +
    > /* Find an entry in the frst-level page table. */
    > #define pud_index(addr) (((addr) >> PUD_SHIFT) & (PTRS_PER_PUD - 1))
    >
    >

    --
    Julien Grall

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