target/linux/bcm47xx/patches-4.19/310-no_highpage.patch

   1 From: Jeff Hansen <jhansen@cardaccess-inc.com>
   2 Subject: [PATCH] no highpage
   3
   4 On ASUS WL-500gP there are many unexpected "Segmentation fault"s that
   5 seem to be caused by a kernel. They can be avoided by:
   6 1) Disabling highpage
   7 2) Using flush_cache_mm in flush_cache_dup_mm
   8
   9 For details see OpenWrt ticket #2035 https://dev.openwrt.org/ticket/2035
  10 ---
  11 --- a/arch/mips/include/asm/page.h
  12 +++ b/arch/mips/include/asm/page.h
  13 @@ -71,6 +71,7 @@ static inline unsigned int page_size_ftl
  14  #endif /* CONFIG_MIPS_HUGE_TLB_SUPPORT */
  15
  16  #include <linux/pfn.h>
  17 +#include <asm/cpu-features.h>
  18
  19  extern void build_clear_page(void);
  20  extern void build_copy_page(void);
  21 @@ -110,11 +111,16 @@ static inline void clear_user_page(void
  22                 flush_data_cache_page((unsigned long)addr);
  23  }
  24
  25 -struct vm_area_struct;
  26 -extern void copy_user_highpage(struct page *to, struct page *from,
  27 -       unsigned long vaddr, struct vm_area_struct *vma);
  28 +static inline void copy_user_page(void *vto, void *vfrom, unsigned long vaddr,
  29 +       struct page *to)
  30 +{
  31 +       extern void (*flush_data_cache_page)(unsigned long addr);
  32
  33 -#define __HAVE_ARCH_COPY_USER_HIGHPAGE
  34 +       copy_page(vto, vfrom);
  35 +       if (!cpu_has_ic_fills_f_dc ||
  36 +           pages_do_alias((unsigned long)vto, vaddr & PAGE_MASK))
  37 +               flush_data_cache_page((unsigned long)vto);
  38 +}
  39
  40  /*
  41   * These are used to make use of C type-checking..
  42 --- a/arch/mips/mm/init.c
  43 +++ b/arch/mips/mm/init.c
  44 @@ -162,30 +162,6 @@ void kunmap_coherent(void)
  45         preempt_enable();
  46  }
  47
  48 -void copy_user_highpage(struct page *to, struct page *from,
  49 -       unsigned long vaddr, struct vm_area_struct *vma)
  50 -{
  51 -       void *vfrom, *vto;
  52 -
  53 -       vto = kmap_atomic(to);
  54 -       if (cpu_has_dc_aliases && cpu_use_kmap_coherent &&
  55 -           page_mapcount(from) && !Page_dcache_dirty(from)) {
  56 -               vfrom = kmap_coherent(from, vaddr);
  57 -               copy_page(vto, vfrom);
  58 -               kunmap_coherent();
  59 -       } else {
  60 -               vfrom = kmap_atomic(from);
  61 -               copy_page(vto, vfrom);
  62 -               kunmap_atomic(vfrom);
  63 -       }
  64 -       if ((!cpu_has_ic_fills_f_dc) ||
  65 -           pages_do_alias((unsigned long)vto, vaddr & PAGE_MASK))
  66 -               flush_data_cache_page((unsigned long)vto);
  67 -       kunmap_atomic(vto);
  68 -       /* Make sure this page is cleared on other CPU's too before using it */
  69 -       smp_wmb();
  70 -}
  71 -
  72  void copy_to_user_page(struct vm_area_struct *vma,
  73         struct page *page, unsigned long vaddr, void *dst, const void *src,
  74         unsigned long len)