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

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);
  

-}