Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / arch / arm / mm / highmem.c

diff --git a/kernel/arch/arm/mm/highmem.c b/kernel/arch/arm/mm/highmem.c
new file mode 100644 (file)
index 0000000..4050e9d
--- /dev/null
+++ b/kernel/arch/arm/mm/highmem.c
@@ -0,0 +1,195 @@
+/*
+ * arch/arm/mm/highmem.c -- ARM highmem support
+ *
+ * Author:     Nicolas Pitre
+ * Created:    september 8, 2008
+ * Copyright:  Marvell Semiconductors Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/highmem.h>
+#include <linux/interrupt.h>
+#include <asm/fixmap.h>
+#include <asm/cacheflush.h>
+#include <asm/tlbflush.h>
+#include "mm.h"
+
+static inline void set_fixmap_pte(int idx, pte_t pte)
+{
+       unsigned long vaddr = __fix_to_virt(idx);
+       pte_t *ptep = pte_offset_kernel(pmd_off_k(vaddr), vaddr);
+
+       set_pte_ext(ptep, pte, 0);
+       local_flush_tlb_kernel_page(vaddr);
+}
+
+static inline pte_t get_fixmap_pte(unsigned long vaddr)
+{
+       pte_t *ptep = pte_offset_kernel(pmd_off_k(vaddr), vaddr);
+
+       return *ptep;
+}
+
+void *kmap(struct page *page)
+{
+       might_sleep();
+       if (!PageHighMem(page))
+               return page_address(page);
+       return kmap_high(page);
+}
+EXPORT_SYMBOL(kmap);
+
+void kunmap(struct page *page)
+{
+       BUG_ON(in_interrupt());
+       if (!PageHighMem(page))
+               return;
+       kunmap_high(page);
+}
+EXPORT_SYMBOL(kunmap);
+
+void *kmap_atomic(struct page *page)
+{
+       pte_t pte = mk_pte(page, kmap_prot);
+       unsigned int idx;
+       unsigned long vaddr;
+       void *kmap;
+       int type;
+
+       preempt_disable_nort();
+       pagefault_disable();
+       if (!PageHighMem(page))
+               return page_address(page);
+
+#ifdef CONFIG_DEBUG_HIGHMEM
+       /*
+        * There is no cache coherency issue when non VIVT, so force the
+        * dedicated kmap usage for better debugging purposes in that case.
+        */
+       if (!cache_is_vivt())
+               kmap = NULL;
+       else
+#endif
+               kmap = kmap_high_get(page);
+       if (kmap)
+               return kmap;
+
+       type = kmap_atomic_idx_push();
+
+       idx = type + KM_TYPE_NR * smp_processor_id();
+       vaddr = __fix_to_virt(idx);
+#ifdef CONFIG_DEBUG_HIGHMEM
+       /*
+        * With debugging enabled, kunmap_atomic forces that entry to 0.
+        * Make sure it was indeed properly unmapped.
+        */
+       BUG_ON(!pte_none(get_fixmap_pte(vaddr)));
+#endif
+       /*
+        * When debugging is off, kunmap_atomic leaves the previous mapping
+        * in place, so the contained TLB flush ensures the TLB is updated
+        * with the new mapping.
+        */
+#ifdef CONFIG_PREEMPT_RT_FULL
+       current->kmap_pte[type] = pte;
+#endif
+       set_fixmap_pte(idx, pte);
+
+       return (void *)vaddr;
+}
+EXPORT_SYMBOL(kmap_atomic);
+
+void __kunmap_atomic(void *kvaddr)
+{
+       unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
+       int idx, type;
+
+       if (kvaddr >= (void *)FIXADDR_START) {
+               type = kmap_atomic_idx();
+               idx = type + KM_TYPE_NR * smp_processor_id();
+
+               if (cache_is_vivt())
+                       __cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);
+#ifdef CONFIG_PREEMPT_RT_FULL
+               current->kmap_pte[type] = __pte(0);
+#endif
+#ifdef CONFIG_DEBUG_HIGHMEM
+               BUG_ON(vaddr != __fix_to_virt(idx));
+#else
+               (void) idx;  /* to kill a warning */
+#endif
+               set_fixmap_pte(idx, __pte(0));
+               kmap_atomic_idx_pop();
+       } else if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP)) {
+               /* this address was obtained through kmap_high_get() */
+               kunmap_high(pte_page(pkmap_page_table[PKMAP_NR(vaddr)]));
+       }
+       pagefault_enable();
+       preempt_enable_nort();
+}
+EXPORT_SYMBOL(__kunmap_atomic);
+
+void *kmap_atomic_pfn(unsigned long pfn)
+{
+       pte_t pte = pfn_pte(pfn, kmap_prot);
+       unsigned long vaddr;
+       int idx, type;
+       struct page *page = pfn_to_page(pfn);
+
+       preempt_disable_nort();
+       pagefault_disable();
+       if (!PageHighMem(page))
+               return page_address(page);
+
+       type = kmap_atomic_idx_push();
+       idx = type + KM_TYPE_NR * smp_processor_id();
+       vaddr = __fix_to_virt(idx);
+#ifdef CONFIG_DEBUG_HIGHMEM
+       BUG_ON(!pte_none(get_fixmap_pte(vaddr)));
+#endif
+#ifdef CONFIG_PREEMPT_RT_FULL
+       current->kmap_pte[type] = pte;
+#endif
+       set_fixmap_pte(idx, pte);
+
+       return (void *)vaddr;
+}
+
+struct page *kmap_atomic_to_page(const void *ptr)
+{
+       unsigned long vaddr = (unsigned long)ptr;
+
+       if (vaddr < FIXADDR_START)
+               return virt_to_page(ptr);
+
+       return pte_page(get_fixmap_pte(vaddr));
+}
+
+#if defined CONFIG_PREEMPT_RT_FULL
+void switch_kmaps(struct task_struct *prev_p, struct task_struct *next_p)
+{
+       int i;
+
+       /*
+        * Clear @prev's kmap_atomic mappings
+        */
+       for (i = 0; i < prev_p->kmap_idx; i++) {
+               int idx = i + KM_TYPE_NR * smp_processor_id();
+
+               set_fixmap_pte(idx, __pte(0));
+       }
+       /*
+        * Restore @next_p's kmap_atomic mappings
+        */
+       for (i = 0; i < next_p->kmap_idx; i++) {
+               int idx = i + KM_TYPE_NR * smp_processor_id();
+
+               if (!pte_none(next_p->kmap_pte[i]))
+                       set_fixmap_pte(idx, next_p->kmap_pte[i]);
+       }
+}
+#endif