Initial import

1 files changed, 176 insertions, 0 deletions

diff --git a/arch/cris/arch-v10/mm/tlb.c b/arch/cris/arch-v10/mm/tlb.c
new file mode 100644
index 000000000..21d78c599
--- /dev/null
+++ b/arch/cris/arch-v10/mm/tlb.c
@@ -0,0 +1,176 @@
+/*
+ *  linux/arch/cris/arch-v10/mm/tlb.c
+ *
+ *  Low level TLB handling
+ *
+ *
+ *  Copyright (C) 2000-2007  Axis Communications AB
+ *
+ *  Authors:   Bjorn Wesen (bjornw@axis.com)
+ *
+ */
+
+#include <asm/tlb.h>
+#include <asm/mmu_context.h>
+#include <arch/svinto.h>
+
+#define D(x)
+
+/* The TLB can host up to 64 different mm contexts at the same time.
+ * The running context is R_MMU_CONTEXT, and each TLB entry contains a
+ * page_id that has to match to give a hit. In page_id_map, we keep track
+ * of which mm's we have assigned which page_id's, so that we know when
+ * to invalidate TLB entries.
+ *
+ * The last page_id is never running - it is used as an invalid page_id
+ * so we can make TLB entries that will never match.
+ *
+ * Notice that we need to make the flushes atomic, otherwise an interrupt
+ * handler that uses vmalloced memory might cause a TLB load in the middle
+ * of a flush causing.
+ */
+
+/* invalidate all TLB entries */
+
+void
+flush_tlb_all(void)
+{
+	int i;
+	unsigned long flags;
+
+	/* the vpn of i & 0xf is so we dont write similar TLB entries
+	 * in the same 4-way entry group. details...
+	 */
+
+	local_irq_save(flags);
+	for(i = 0; i < NUM_TLB_ENTRIES; i++) {
+		*R_TLB_SELECT = ( IO_FIELD(R_TLB_SELECT, index, i) );
+		*R_TLB_HI = ( IO_FIELD(R_TLB_HI, page_id, INVALID_PAGEID ) |
+			      IO_FIELD(R_TLB_HI, vpn,     i & 0xf ) );
+
+		*R_TLB_LO = ( IO_STATE(R_TLB_LO, global,no       ) |
+			      IO_STATE(R_TLB_LO, valid, no       ) |
+			      IO_STATE(R_TLB_LO, kernel,no	 ) |
+			      IO_STATE(R_TLB_LO, we,    no       ) |
+			      IO_FIELD(R_TLB_LO, pfn,   0        ) );
+	}
+	local_irq_restore(flags);
+	D(printk("tlb: flushed all\n"));
+}
+
+/* invalidate the selected mm context only */
+
+void
+flush_tlb_mm(struct mm_struct *mm)
+{
+	int i;
+	int page_id = mm->context.page_id;
+	unsigned long flags;
+
+	D(printk("tlb: flush mm context %d (%p)\n", page_id, mm));
+
+	if(page_id == NO_CONTEXT)
+		return;
+
+	/* mark the TLB entries that match the page_id as invalid.
+	 * here we could also check the _PAGE_GLOBAL bit and NOT flush
+	 * global pages. is it worth the extra I/O ?
+	 */
+
+	local_irq_save(flags);
+	for(i = 0; i < NUM_TLB_ENTRIES; i++) {
+		*R_TLB_SELECT = IO_FIELD(R_TLB_SELECT, index, i);
+		if (IO_EXTRACT(R_TLB_HI, page_id, *R_TLB_HI) == page_id) {
+			*R_TLB_HI = ( IO_FIELD(R_TLB_HI, page_id, INVALID_PAGEID ) |
+				      IO_FIELD(R_TLB_HI, vpn,     i & 0xf ) );
+
+			*R_TLB_LO = ( IO_STATE(R_TLB_LO, global,no  ) |
+				      IO_STATE(R_TLB_LO, valid, no  ) |
+				      IO_STATE(R_TLB_LO, kernel,no  ) |
+				      IO_STATE(R_TLB_LO, we,    no  ) |
+				      IO_FIELD(R_TLB_LO, pfn,   0   ) );
+		}
+	}
+	local_irq_restore(flags);
+}
+
+/* invalidate a single page */
+
+void flush_tlb_page(struct vm_area_struct *vma, unsigned long addr)
+{
+	struct mm_struct *mm = vma->vm_mm;
+	int page_id = mm->context.page_id;
+	int i;
+	unsigned long flags;
+
+	D(printk("tlb: flush page %p in context %d (%p)\n", addr, page_id, mm));
+
+	if(page_id == NO_CONTEXT)
+		return;
+
+	addr &= PAGE_MASK; /* perhaps not necessary */
+
+	/* invalidate those TLB entries that match both the mm context
+	 * and the virtual address requested
+	 */
+
+	local_irq_save(flags);
+	for(i = 0; i < NUM_TLB_ENTRIES; i++) {
+		unsigned long tlb_hi;
+		*R_TLB_SELECT = IO_FIELD(R_TLB_SELECT, index, i);
+		tlb_hi = *R_TLB_HI;
+		if (IO_EXTRACT(R_TLB_HI, page_id, tlb_hi) == page_id &&
+		    (tlb_hi & PAGE_MASK) == addr) {
+			*R_TLB_HI = IO_FIELD(R_TLB_HI, page_id, INVALID_PAGEID ) |
+				addr; /* same addr as before works. */
+
+			*R_TLB_LO = ( IO_STATE(R_TLB_LO, global,no  ) |
+				      IO_STATE(R_TLB_LO, valid, no  ) |
+				      IO_STATE(R_TLB_LO, kernel,no  ) |
+				      IO_STATE(R_TLB_LO, we,    no  ) |
+				      IO_FIELD(R_TLB_LO, pfn,   0   ) );
+		}
+	}
+	local_irq_restore(flags);
+}
+
+/*
+ * Initialize the context related info for a new mm_struct
+ * instance.
+ */
+
+int
+init_new_context(struct task_struct *tsk, struct mm_struct *mm)
+{
+	mm->context.page_id = NO_CONTEXT;
+	return 0;
+}
+
+/* called in schedule() just before actually doing the switch_to */
+
+void switch_mm(struct mm_struct *prev, struct mm_struct *next,
+	struct task_struct *tsk)
+{
+	if (prev != next) {
+		/* make sure we have a context */
+		get_mmu_context(next);
+
+		/* remember the pgd for the fault handlers
+		 * this is similar to the pgd register in some other CPU's.
+		 * we need our own copy of it because current and active_mm
+		 * might be invalid at points where we still need to derefer
+		 * the pgd.
+		 */
+
+		per_cpu(current_pgd, smp_processor_id()) = next->pgd;
+
+		/* switch context in the MMU */
+
+		D(printk(KERN_DEBUG "switching mmu_context to %d (%p)\n",
+			next->context, next));
+
+		*R_MMU_CONTEXT = IO_FIELD(R_MMU_CONTEXT,
+					  page_id, next->context.page_id);
+	}
+}
+