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

Guo Ren
2020-09-23T00:05:41Z

Acked-by: Guo Ren <guoren@kernel.org>

On Sat, Sep 19, 2020 at 5:50 PM Thomas Gleixner <tglx@linutronix.de> wrote:
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Cc: Guo Ren <guoren@kernel.org>
> Cc: linux-csky@vger.kernel.org
> ---
> 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/