1 files changed, 120 insertions, 0 deletions

diff --git a/arch/sparc/mm/highmem.c b/arch/sparc/mm/highmem.c
new file mode 100644
index 000000000000..4d8ed9c65182
--- /dev/null
+++ b/arch/sparc/mm/highmem.c
@@ -0,0 +1,120 @@
+/*
+ *  highmem.c: virtual kernel memory mappings for high memory
+ *
+ *  Provides kernel-static versions of atomic kmap functions originally
+ *  found as inlines in include/asm-sparc/highmem.h.  These became
+ *  needed as kmap_atomic() and kunmap_atomic() started getting
+ *  called from within modules.
+ *  -- Tomas Szepe <szepe@pinerecords.com>, September 2002
+ *
+ *  But kmap_atomic() and kunmap_atomic() cannot be inlined in
+ *  modules because they are loaded with btfixup-ped functions.
+ */
+
+/*
+ * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap
+ * gives a more generic (and caching) interface. But kmap_atomic can
+ * be used in IRQ contexts, so in some (very limited) cases we need it.
+ *
+ * XXX This is an old text. Actually, it's good to use atomic kmaps,
+ * provided you remember that they are atomic and not try to sleep
+ * with a kmap taken, much like a spinlock. Non-atomic kmaps are
+ * shared by CPUs, and so precious, and establishing them requires IPI.
+ * Atomic kmaps are lightweight and we may have NCPUS more of them.
+ */
+#include <linux/mm.h>
+#include <linux/highmem.h>
+#include <asm/pgalloc.h>
+#include <asm/cacheflush.h>
+#include <asm/tlbflush.h>
+#include <asm/fixmap.h>
+
+void *kmap_atomic(struct page *page, enum km_type type)
+{
+        unsigned long idx;
+        unsigned long vaddr;
+
+        /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
+        inc_preempt_count();
+        if (!PageHighMem(page))
+                return page_address(page);
+
+        idx = type + KM_TYPE_NR*smp_processor_id();
+        vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
+
+/* XXX Fix - Anton */
+#if 0
+        __flush_cache_one(vaddr);
+#else
+        flush_cache_all();
+#endif
+
+#ifdef CONFIG_DEBUG_HIGHMEM
+        BUG_ON(!pte_none(*(kmap_pte-idx)));
+#endif
+        set_pte(kmap_pte-idx, mk_pte(page, kmap_prot));
+/* XXX Fix - Anton */
+#if 0
+        __flush_tlb_one(vaddr);
+#else
+        flush_tlb_all();
+#endif
+
+        return (void*) vaddr;
+}
+
+void kunmap_atomic(void *kvaddr, enum km_type type)
+{
+#ifdef CONFIG_DEBUG_HIGHMEM
+        unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
+        unsigned long idx = type + KM_TYPE_NR*smp_processor_id();
+
+        if (vaddr < FIXADDR_START) { // FIXME
+                dec_preempt_count();
+                preempt_check_resched();
+                return;
+        }
+
+        BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN+idx));
+
+/* XXX Fix - Anton */
+#if 0
+        __flush_cache_one(vaddr);
+#else
+        flush_cache_all();
+#endif
+
+        /*
+         * force other mappings to Oops if they'll try to access
+         * this pte without first remap it
+         */
+        pte_clear(&init_mm, vaddr, kmap_pte-idx);
+/* XXX Fix - Anton */
+#if 0
+        __flush_tlb_one(vaddr);
+#else
+        flush_tlb_all();
+#endif
+#endif
+
+        dec_preempt_count();
+        preempt_check_resched();
+}
+
+/* We may be fed a pagetable here by ptep_to_xxx and others. */
+struct page *kmap_atomic_to_page(void *ptr)
+{
+        unsigned long idx, vaddr = (unsigned long)ptr;
+        pte_t *pte;
+
+        if (vaddr < SRMMU_NOCACHE_VADDR)
+                return virt_to_page(ptr);
+        if (vaddr < PKMAP_BASE)
+                return pfn_to_page(__nocache_pa(vaddr) >> PAGE_SHIFT);
+        BUG_ON(vaddr < FIXADDR_START);
+        BUG_ON(vaddr > FIXADDR_TOP);
+
+        idx = virt_to_fix(vaddr);
+        pte = kmap_pte - (idx - FIX_KMAP_BEGIN);
+        return pte_page(*pte);
+}