rt-patches/0204-arm-Enable-highmem-for-rt.patch

   1 From 93564d8227dfae7268b5cdd20827dcf321d38872 Mon Sep 17 00:00:00 2001
   2 From: Thomas Gleixner <tglx@linutronix.de>
   3 Date: Wed, 13 Feb 2013 11:03:11 +0100
   4 Subject: [PATCH 204/366] arm: Enable highmem for rt
   5
   6 fixup highmem for ARM.
   7
   8 Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
   9 ---
  10  arch/arm/include/asm/switch_to.h |  8 +++++++
  11  arch/arm/mm/highmem.c            | 45 +++++++++++++++++++++++++++++++++++-----
  12  include/linux/highmem.h          |  1 +
  13  3 files changed, 49 insertions(+), 5 deletions(-)
  14
  15 diff --git a/arch/arm/include/asm/switch_to.h b/arch/arm/include/asm/switch_to.h
  16 index 12ebfcc..c962084 100644
  17 --- a/arch/arm/include/asm/switch_to.h
  18 +++ b/arch/arm/include/asm/switch_to.h
  19 @@ -3,6 +3,13 @@
  20
  21  #include <linux/thread_info.h>
  22
  23 +#if defined CONFIG_PREEMPT_RT_FULL && defined CONFIG_HIGHMEM
  24 +void switch_kmaps(struct task_struct *prev_p, struct task_struct *next_p);
  25 +#else
  26 +static inline void
  27 +switch_kmaps(struct task_struct *prev_p, struct task_struct *next_p) { }
  28 +#endif
  29 +
  30  /*
  31   * For v7 SMP cores running a preemptible kernel we may be pre-empted
  32   * during a TLB maintenance operation, so execute an inner-shareable dsb
  33 @@ -25,6 +32,7 @@ extern struct task_struct *__switch_to(struct task_struct *, struct thread_info
  34  #define switch_to(prev,next,last)                                      \
  35  do {                                                                   \
  36         __complete_pending_tlbi();                                      \
  37 +       switch_kmaps(prev, next);                                       \
  38         last = __switch_to(prev,task_thread_info(prev), task_thread_info(next));        \
  39  } while (0)
  40
  41 diff --git a/arch/arm/mm/highmem.c b/arch/arm/mm/highmem.c
  42 index eb4b225d..deabc36 100644
  43 --- a/arch/arm/mm/highmem.c
  44 +++ b/arch/arm/mm/highmem.c
  45 @@ -54,12 +54,13 @@ EXPORT_SYMBOL(kunmap);
  46
  47  void *kmap_atomic(struct page *page)
  48  {
  49 +       pte_t pte = mk_pte(page, kmap_prot);
  50         unsigned int idx;
  51         unsigned long vaddr;
  52         void *kmap;
  53         int type;
  54
  55 -       preempt_disable();
  56 +       preempt_disable_nort();
  57         pagefault_disable();
  58         if (!PageHighMem(page))
  59                 return page_address(page);
  60 @@ -93,7 +94,10 @@ void *kmap_atomic(struct page *page)
  61          * in place, so the contained TLB flush ensures the TLB is updated
  62          * with the new mapping.
  63          */
  64 -       set_fixmap_pte(idx, mk_pte(page, kmap_prot));
  65 +#ifdef CONFIG_PREEMPT_RT_FULL
  66 +       current->kmap_pte[type] = pte;
  67 +#endif
  68 +       set_fixmap_pte(idx, pte);
  69
  70         return (void *)vaddr;
  71  }
  72 @@ -110,6 +114,9 @@ void __kunmap_atomic(void *kvaddr)
  73
  74                 if (cache_is_vivt())
  75                         __cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);
  76 +#ifdef CONFIG_PREEMPT_RT_FULL
  77 +               current->kmap_pte[type] = __pte(0);
  78 +#endif
  79  #ifdef CONFIG_DEBUG_HIGHMEM
  80                 BUG_ON(vaddr != __fix_to_virt(idx));
  81  #else
  82 @@ -122,17 +129,18 @@ void __kunmap_atomic(void *kvaddr)
  83                 kunmap_high(pte_page(pkmap_page_table[PKMAP_NR(vaddr)]));
  84         }
  85         pagefault_enable();
  86 -       preempt_enable();
  87 +       preempt_enable_nort();
  88  }
  89  EXPORT_SYMBOL(__kunmap_atomic);
  90
  91  void *kmap_atomic_pfn(unsigned long pfn)
  92  {
  93 +       pte_t pte = pfn_pte(pfn, kmap_prot);
  94         unsigned long vaddr;
  95         int idx, type;
  96         struct page *page = pfn_to_page(pfn);
  97
  98 -       preempt_disable();
  99 +       preempt_disable_nort();
 100         pagefault_disable();
 101         if (!PageHighMem(page))
 102                 return page_address(page);
 103 @@ -143,7 +151,34 @@ void *kmap_atomic_pfn(unsigned long pfn)
 104  #ifdef CONFIG_DEBUG_HIGHMEM
 105         BUG_ON(!pte_none(get_fixmap_pte(vaddr)));
 106  #endif
 107 -       set_fixmap_pte(idx, pfn_pte(pfn, kmap_prot));
 108 +#ifdef CONFIG_PREEMPT_RT_FULL
 109 +       current->kmap_pte[type] = pte;
 110 +#endif
 111 +       set_fixmap_pte(idx, pte);
 112
 113         return (void *)vaddr;
 114  }
 115 +#if defined CONFIG_PREEMPT_RT_FULL
 116 +void switch_kmaps(struct task_struct *prev_p, struct task_struct *next_p)
 117 +{
 118 +       int i;
 119 +
 120 +       /*
 121 +        * Clear @prev's kmap_atomic mappings
 122 +        */
 123 +       for (i = 0; i < prev_p->kmap_idx; i++) {
 124 +               int idx = i + KM_TYPE_NR * smp_processor_id();
 125 +
 126 +               set_fixmap_pte(idx, __pte(0));
 127 +       }
 128 +       /*
 129 +        * Restore @next_p's kmap_atomic mappings
 130 +        */
 131 +       for (i = 0; i < next_p->kmap_idx; i++) {
 132 +               int idx = i + KM_TYPE_NR * smp_processor_id();
 133 +
 134 +               if (!pte_none(next_p->kmap_pte[i]))
 135 +                       set_fixmap_pte(idx, next_p->kmap_pte[i]);
 136 +       }
 137 +}
 138 +#endif
 139 diff --git a/include/linux/highmem.h b/include/linux/highmem.h
 140 index 2f56829..a2a50f5 100644
 141 --- a/include/linux/highmem.h
 142 +++ b/include/linux/highmem.h
 143 @@ -7,6 +7,7 @@
 144  #include <linux/mm.h>
 145  #include <linux/uaccess.h>
 146  #include <linux/hardirq.h>
 147 +#include <linux/sched.h>
 148
 149  #include <asm/cacheflush.h>
 150
 151 --
 152 1.9.1
 153