target/linux/brcm47xx/patches-4.19/160-kmap_coherent.patch

   1 From: Jeff Hansen <jhansen@cardaccess-inc.com>
   2 Subject: [PATCH] kmap_coherent
   3
   4 On ASUS WL-500gP there are some "Data bus error"s when executing simple
   5 commands liks "ps" or "cat /proc/1/cmdline".
   6
   7 This fixes OpenWrt ticket #1485: https://dev.openwrt.org/ticket/1485
   8 ---
   9 --- a/arch/mips/include/asm/cpu-features.h
  10 +++ b/arch/mips/include/asm/cpu-features.h
  11 @@ -226,6 +226,9 @@
  12  #ifndef cpu_has_local_ebase
  13  #define cpu_has_local_ebase    1
  14  #endif
  15 +#ifndef cpu_use_kmap_coherent
  16 +#define cpu_use_kmap_coherent 1
  17 +#endif
  18
  19  /*
  20   * I-Cache snoops remote store.         This only matters on SMP.  Some multiprocessors
  21 --- a/arch/mips/include/asm/mach-bcm47xx/cpu-feature-overrides.h
  22 +++ b/arch/mips/include/asm/mach-bcm47xx/cpu-feature-overrides.h
  23 @@ -80,4 +80,6 @@
  24  #define cpu_scache_line_size()         0
  25  #define cpu_has_vz                     0
  26
  27 +#define cpu_use_kmap_coherent          0
  28 +
  29  #endif /* __ASM_MACH_BCM47XX_CPU_FEATURE_OVERRIDES_H */
  30 --- a/arch/mips/mm/c-r4k.c
  31 +++ b/arch/mips/mm/c-r4k.c
  32 @@ -694,7 +694,7 @@ static inline void local_r4k_flush_cache
  33                 map_coherent = (cpu_has_dc_aliases &&
  34                                 page_mapcount(page) &&
  35                                 !Page_dcache_dirty(page));
  36 -               if (map_coherent)
  37 +               if (map_coherent && cpu_use_kmap_coherent)
  38                         vaddr = kmap_coherent(page, addr);
  39                 else
  40                         vaddr = kmap_atomic(page);
  41 @@ -719,7 +719,7 @@ static inline void local_r4k_flush_cache
  42         }
  43
  44         if (vaddr) {
  45 -               if (map_coherent)
  46 +               if (map_coherent && cpu_use_kmap_coherent)
  47                         kunmap_coherent();
  48                 else
  49                         kunmap_atomic(vaddr);
  50 --- a/arch/mips/mm/init.c
  51 +++ b/arch/mips/mm/init.c
  52 @@ -168,7 +168,7 @@ void copy_user_highpage(struct page *to,
  53         void *vfrom, *vto;
  54
  55         vto = kmap_atomic(to);
  56 -       if (cpu_has_dc_aliases &&
  57 +       if (cpu_has_dc_aliases && cpu_use_kmap_coherent &&
  58             page_mapcount(from) && !Page_dcache_dirty(from)) {
  59                 vfrom = kmap_coherent(from, vaddr);
  60                 copy_page(vto, vfrom);
  61 @@ -190,7 +190,7 @@ void copy_to_user_page(struct vm_area_st
  62         struct page *page, unsigned long vaddr, void *dst, const void *src,
  63         unsigned long len)
  64  {
  65 -       if (cpu_has_dc_aliases &&
  66 +       if (cpu_has_dc_aliases && cpu_use_kmap_coherent &&
  67             page_mapcount(page) && !Page_dcache_dirty(page)) {
  68                 void *vto = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
  69                 memcpy(vto, src, len);
  70 @@ -208,7 +208,7 @@ void copy_from_user_page(struct vm_area_
  71         struct page *page, unsigned long vaddr, void *dst, const void *src,
  72         unsigned long len)
  73  {
  74 -       if (cpu_has_dc_aliases &&
  75 +       if (cpu_has_dc_aliases && cpu_use_kmap_coherent &&
  76             page_mapcount(page) && !Page_dcache_dirty(page)) {
  77                 void *vfrom = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
  78                 memcpy(dst, vfrom, len);