Re: [patch RFC 06/15] csky/mm/highmem: Switch to generic kmap atomic

[Guo Ren]

Acked-by: Guo Ren <guoren@xxxxxxxxxx>

On Sat, Sep 19, 2020 at 5:50 PM Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
>
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Guo Ren <guoren@xxxxxxxxxx>
> Cc: linux-csky@xxxxxxxxxxxxxxx
> ---
> Note: Completely untested
> ---
>  arch/csky/Kconfig               |    1
>  arch/csky/include/asm/highmem.h |    4 +-
>  arch/csky/mm/highmem.c          |   75 ----------------------------------------
>  3 files changed, 5 insertions(+), 75 deletions(-)
>
> --- a/arch/csky/Kconfig
> +++ b/arch/csky/Kconfig
> @@ -285,6 +285,7 @@ config NR_CPUS
>  config HIGHMEM
>         bool "High Memory Support"
>         depends on !CPU_CK610
> +       select KMAP_ATOMIC_GENERIC
>         default y
>
>  config FORCE_MAX_ZONEORDER
> --- a/arch/csky/include/asm/highmem.h
> +++ b/arch/csky/include/asm/highmem.h
> @@ -32,10 +32,12 @@ extern pte_t *pkmap_page_table;
>
>  #define ARCH_HAS_KMAP_FLUSH_TLB
>  extern void kmap_flush_tlb(unsigned long addr);
> -extern void *kmap_atomic_pfn(unsigned long pfn);
>
>  #define flush_cache_kmaps() do {} while (0)
>
> +#define arch_kmap_temp_post_map(vaddr, pteval) kmap_flush_tlb(vaddr)
> +#define arch_kmap_temp_post_unmap(vaddr)       kmap_flush_tlb(vaddr)
> +
>  extern void kmap_init(void);
>
>  #endif /* __KERNEL__ */
> --- a/arch/csky/mm/highmem.c
> +++ b/arch/csky/mm/highmem.c
> @@ -9,8 +9,6 @@
>  #include <asm/tlbflush.h>
>  #include <asm/cacheflush.h>
>
> -static pte_t *kmap_pte;
> -
>  unsigned long highstart_pfn, highend_pfn;
>
>  void kmap_flush_tlb(unsigned long addr)
> @@ -19,67 +17,7 @@ void kmap_flush_tlb(unsigned long addr)
>  }
>  EXPORT_SYMBOL(kmap_flush_tlb);
>
> -void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
> -{
> -       unsigned long vaddr;
> -       int idx, type;
> -
> -       type = kmap_atomic_idx_push();
> -       idx = type + KM_TYPE_NR*smp_processor_id();
> -       vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
> -#ifdef CONFIG_DEBUG_HIGHMEM
> -       BUG_ON(!pte_none(*(kmap_pte - idx)));
> -#endif
> -       set_pte(kmap_pte-idx, mk_pte(page, prot));
> -       flush_tlb_one((unsigned long)vaddr);
> -
> -       return (void *)vaddr;
> -}
> -EXPORT_SYMBOL(kmap_atomic_high_prot);
> -
> -void kunmap_atomic_high(void *kvaddr)
> -{
> -       unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
> -       int idx;
> -
> -       if (vaddr < FIXADDR_START)
> -               return;
> -
> -#ifdef CONFIG_DEBUG_HIGHMEM
> -       idx = KM_TYPE_NR*smp_processor_id() + kmap_atomic_idx();
> -
> -       BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
> -
> -       pte_clear(&init_mm, vaddr, kmap_pte - idx);
> -       flush_tlb_one(vaddr);
> -#else
> -       (void) idx; /* to kill a warning */
> -#endif
> -       kmap_atomic_idx_pop();
> -}
> -EXPORT_SYMBOL(kunmap_atomic_high);
> -
> -/*
> - * This is the same as kmap_atomic() but can map memory that doesn't
> - * have a struct page associated with it.
> - */
> -void *kmap_atomic_pfn(unsigned long pfn)
> -{
> -       unsigned long vaddr;
> -       int idx, type;
> -
> -       pagefault_disable();
> -
> -       type = kmap_atomic_idx_push();
> -       idx = type + KM_TYPE_NR*smp_processor_id();
> -       vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
> -       set_pte(kmap_pte-idx, pfn_pte(pfn, PAGE_KERNEL));
> -       flush_tlb_one(vaddr);
> -
> -       return (void *) vaddr;
> -}
> -
> -static void __init kmap_pages_init(void)
> +void __init kmap_init(void)
>  {
>         unsigned long vaddr;
>         pgd_t *pgd;
> @@ -96,14 +34,3 @@ static void __init kmap_pages_init(void)
>         pte = pte_offset_kernel(pmd, vaddr);
>         pkmap_page_table = pte;
>  }
> -
> -void __init kmap_init(void)
> -{
> -       unsigned long vaddr;
> -
> -       kmap_pages_init();
> -
> -       vaddr = __fix_to_virt(FIX_KMAP_BEGIN);
> -
> -       kmap_pte = pte_offset_kernel((pmd_t *)pgd_offset_k(vaddr), vaddr);
> -}
>


-- 
Best Regards
 Guo Ren

ML: https://lore.kernel.org/linux-csky/