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Re: HIGHMEM fix for r24k

To: "Ralf Baechle" <ralf@linux-mips.org>
Subject: Re: HIGHMEM fix for r24k
From: "Jon Fraser" <jfraser@broadcom.com>
Date: Mon, 4 May 2009 10:49:46 -0400
Cc: jfraser@broadcom.com, "linux-mips@linux-mips.org" <linux-mips@linux-mips.org>
In-reply-to: <20090425092446.GA9845@linux-mips.org>
Organization: Broadcom
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <1240525424.15448.33.camel@chaos.ne.broadcom.com> <20090424154349.GB3614@linux-mips.org> <1240589632.15448.38.camel@chaos.ne.broadcom.com> <20090425092446.GA9845@linux-mips.org>
Reply-to: jfraser@broadcom.com
Sender: linux-mips-bounce@linux-mips.org
Hi Ralf,

       Just wanted to acknowledge your email.   I've been playing catch
up for the last week after spending a large amount of unscheduled time
finding the root cause of this bug.  I should be able to get to applying
this patch this week.  Were these against HOT or 2.6.29?

Jon


On Sat, 2009-04-25 at 02:24 -0700, Ralf Baechle wrote:
> On Fri, Apr 24, 2009 at 12:13:52PM -0400, Jon Fraser wrote:
> 
> > That's why I haven't proposed a fix yet.  But there are other people
> > dealing with the same HIGHMEM issues and I wanted them to know about the
> > problem.
> 
> Can you test below fix?  Thanks,
> 
>   Ralf
> 
> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
> 
>  arch/mips/include/asm/fixmap.h  |    3 +++
>  arch/mips/include/asm/highmem.h |    6 ++++--
>  arch/mips/mm/highmem.c          |   25 +++++++++++++++++++------
>  arch/mips/mm/init.c             |   26 --------------------------
>  4 files changed, 26 insertions(+), 34 deletions(-)
> 
> diff --git a/arch/mips/include/asm/fixmap.h b/arch/mips/include/asm/fixmap.h
> index 9cc8522..0f5caa1 100644
> --- a/arch/mips/include/asm/fixmap.h
> +++ b/arch/mips/include/asm/fixmap.h
> @@ -108,6 +108,9 @@ static inline unsigned long virt_to_fix(const unsigned 
> long vaddr)
>       return __virt_to_fix(vaddr);
>  }
>  
> +#define kmap_get_fixmap_pte(vaddr)                                   \
> +     pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)), 
> (vaddr)), (vaddr))
> +
>  /*
>   * Called from pgtable_init()
>   */
> diff --git a/arch/mips/include/asm/highmem.h b/arch/mips/include/asm/highmem.h
> index 4374ab2..25adfb0 100644
> --- a/arch/mips/include/asm/highmem.h
> +++ b/arch/mips/include/asm/highmem.h
> @@ -30,8 +30,6 @@
>  /* declarations for highmem.c */
>  extern unsigned long highstart_pfn, highend_pfn;
>  
> -extern pte_t *kmap_pte;
> -extern pgprot_t kmap_prot;
>  extern pte_t *pkmap_page_table;
>  
>  /*
> @@ -62,6 +60,10 @@ extern struct page *__kmap_atomic_to_page(void *ptr);
>  
>  #define flush_cache_kmaps()  flush_cache_all()
>  
> +extern void kmap_init(void);
> +
> +#define kmap_prot PAGE_KERNEL
> +
>  #endif /* __KERNEL__ */
>  
>  #endif /* _ASM_HIGHMEM_H */
> diff --git a/arch/mips/mm/highmem.c b/arch/mips/mm/highmem.c
> index 4481656..2b1309b 100644
> --- a/arch/mips/mm/highmem.c
> +++ b/arch/mips/mm/highmem.c
> @@ -1,7 +1,12 @@
>  #include <linux/module.h>
>  #include <linux/highmem.h>
> +#include <asm/fixmap.h>
>  #include <asm/tlbflush.h>
>  
> +static pte_t *kmap_pte;
> +
> +unsigned long highstart_pfn, highend_pfn;
> +
>  void *__kmap(struct page *page)
>  {
>       void *addr;
> @@ -14,6 +19,7 @@ void *__kmap(struct page *page)
>  
>       return addr;
>  }
> +EXPORT_SYMBOL(__kmap);
>  
>  void __kunmap(struct page *page)
>  {
> @@ -22,6 +28,7 @@ void __kunmap(struct page *page)
>               return;
>       kunmap_high(page);
>  }
> +EXPORT_SYMBOL(__kunmap);
>  
>  /*
>   * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
> @@ -48,11 +55,12 @@ void *__kmap_atomic(struct page *page, enum km_type type)
>  #ifdef CONFIG_DEBUG_HIGHMEM
>       BUG_ON(!pte_none(*(kmap_pte - idx)));
>  #endif
> -     set_pte(kmap_pte-idx, mk_pte(page, kmap_prot));
> +     set_pte(kmap_pte-idx, mk_pte(page, PAGE_KERNEL));
>       local_flush_tlb_one((unsigned long)vaddr);
>  
>       return (void*) vaddr;
>  }
> +EXPORT_SYMBOL(__kmap_atomic);
>  
>  void __kunmap_atomic(void *kvaddr, enum km_type type)
>  {
> @@ -77,6 +85,7 @@ void __kunmap_atomic(void *kvaddr, enum km_type type)
>  
>       pagefault_enable();
>  }
> +EXPORT_SYMBOL(__kunmap_atomic);
>  
>  /*
>   * This is the same as kmap_atomic() but can map memory that doesn't
> @@ -92,7 +101,7 @@ void *kmap_atomic_pfn(unsigned long pfn, enum km_type type)
>       debug_kmap_atomic(type);
>       idx = type + KM_TYPE_NR*smp_processor_id();
>       vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
> -     set_pte(kmap_pte-idx, pfn_pte(pfn, kmap_prot));
> +     set_pte(kmap_pte-idx, pfn_pte(pfn, PAGE_KERNEL));
>       flush_tlb_one(vaddr);
>  
>       return (void*) vaddr;
> @@ -111,7 +120,11 @@ struct page *__kmap_atomic_to_page(void *ptr)
>       return pte_page(*pte);
>  }
>  
> -EXPORT_SYMBOL(__kmap);
> -EXPORT_SYMBOL(__kunmap);
> -EXPORT_SYMBOL(__kmap_atomic);
> -EXPORT_SYMBOL(__kunmap_atomic);
> +void __init kmap_init(void)
> +{
> +     unsigned long kmap_vstart;
> +
> +     /* cache the first kmap pte */
> +     kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
> +     kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
> +}
> diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
> index d934894..c551129 100644
> --- a/arch/mips/mm/init.c
> +++ b/arch/mips/mm/init.c
> @@ -104,14 +104,6 @@ unsigned long setup_zero_pages(void)
>       return 1UL << order;
>  }
>  
> -/*
> - * These are almost like kmap_atomic / kunmap_atmic except they take an
> - * additional address argument as the hint.
> - */
> -
> -#define kmap_get_fixmap_pte(vaddr)                                   \
> -     pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)), 
> (vaddr)), (vaddr))
> -
>  #ifdef CONFIG_MIPS_MT_SMTC
>  static pte_t *kmap_coherent_pte;
>  static void __init kmap_coherent_init(void)
> @@ -264,24 +256,6 @@ void copy_from_user_page(struct vm_area_struct *vma,
>       }
>  }
>  
> -#ifdef CONFIG_HIGHMEM
> -unsigned long highstart_pfn, highend_pfn;
> -
> -pte_t *kmap_pte;
> -pgprot_t kmap_prot;
> -
> -static void __init kmap_init(void)
> -{
> -     unsigned long kmap_vstart;
> -
> -     /* cache the first kmap pte */
> -     kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
> -     kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
> -
> -     kmap_prot = PAGE_KERNEL;
> -}
> -#endif /* CONFIG_HIGHMEM */
> -
>  void __init fixrange_init(unsigned long start, unsigned long end,
>       pgd_t *pgd_base)
>  {
> 



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