From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Wed, 5 Aug 2015 17:04:01 -0300
Subject: Initial import

---
 arch/um/include/asm/tlb.h | 134 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 134 insertions(+)
 create mode 100644 arch/um/include/asm/tlb.h

(limited to 'arch/um/include/asm/tlb.h')

diff --git a/arch/um/include/asm/tlb.h b/arch/um/include/asm/tlb.h
new file mode 100644
index 000000000..16eb63fac
--- /dev/null
+++ b/arch/um/include/asm/tlb.h
@@ -0,0 +1,134 @@
+#ifndef __UM_TLB_H
+#define __UM_TLB_H
+
+#include <linux/pagemap.h>
+#include <linux/swap.h>
+#include <asm/percpu.h>
+#include <asm/pgalloc.h>
+#include <asm/tlbflush.h>
+
+#define tlb_start_vma(tlb, vma) do { } while (0)
+#define tlb_end_vma(tlb, vma) do { } while (0)
+#define tlb_flush(tlb) flush_tlb_mm((tlb)->mm)
+
+/* struct mmu_gather is an opaque type used by the mm code for passing around
+ * any data needed by arch specific code for tlb_remove_page.
+ */
+struct mmu_gather {
+	struct mm_struct	*mm;
+	unsigned int		need_flush; /* Really unmapped some ptes? */
+	unsigned long		start;
+	unsigned long		end;
+	unsigned int		fullmm; /* non-zero means full mm flush */
+};
+
+static inline void __tlb_remove_tlb_entry(struct mmu_gather *tlb, pte_t *ptep,
+					  unsigned long address)
+{
+	if (tlb->start > address)
+		tlb->start = address;
+	if (tlb->end < address + PAGE_SIZE)
+		tlb->end = address + PAGE_SIZE;
+}
+
+static inline void init_tlb_gather(struct mmu_gather *tlb)
+{
+	tlb->need_flush = 0;
+
+	tlb->start = TASK_SIZE;
+	tlb->end = 0;
+
+	if (tlb->fullmm) {
+		tlb->start = 0;
+		tlb->end = TASK_SIZE;
+	}
+}
+
+static inline void
+tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long start, unsigned long end)
+{
+	tlb->mm = mm;
+	tlb->start = start;
+	tlb->end = end;
+	tlb->fullmm = !(start | (end+1));
+
+	init_tlb_gather(tlb);
+}
+
+extern void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
+			       unsigned long end);
+
+static inline void
+tlb_flush_mmu_tlbonly(struct mmu_gather *tlb)
+{
+	flush_tlb_mm_range(tlb->mm, tlb->start, tlb->end);
+}
+
+static inline void
+tlb_flush_mmu_free(struct mmu_gather *tlb)
+{
+	init_tlb_gather(tlb);
+}
+
+static inline void
+tlb_flush_mmu(struct mmu_gather *tlb)
+{
+	if (!tlb->need_flush)
+		return;
+
+	tlb_flush_mmu_tlbonly(tlb);
+	tlb_flush_mmu_free(tlb);
+}
+
+/* tlb_finish_mmu
+ *	Called at the end of the shootdown operation to free up any resources
+ *	that were required.
+ */
+static inline void
+tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
+{
+	tlb_flush_mmu(tlb);
+
+	/* keep the page table cache within bounds */
+	check_pgt_cache();
+}
+
+/* tlb_remove_page
+ *	Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)),
+ *	while handling the additional races in SMP caused by other CPUs
+ *	caching valid mappings in their TLBs.
+ */
+static inline int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
+{
+	tlb->need_flush = 1;
+	free_page_and_swap_cache(page);
+	return 1; /* avoid calling tlb_flush_mmu */
+}
+
+static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
+{
+	__tlb_remove_page(tlb, page);
+}
+
+/**
+ * tlb_remove_tlb_entry - remember a pte unmapping for later tlb invalidation.
+ *
+ * Record the fact that pte's were really umapped in ->need_flush, so we can
+ * later optimise away the tlb invalidate.   This helps when userspace is
+ * unmapping already-unmapped pages, which happens quite a lot.
+ */
+#define tlb_remove_tlb_entry(tlb, ptep, address)		\
+	do {							\
+		tlb->need_flush = 1;				\
+		__tlb_remove_tlb_entry(tlb, ptep, address);	\
+	} while (0)
+
+#define pte_free_tlb(tlb, ptep, addr) __pte_free_tlb(tlb, ptep, addr)
+
+#define pud_free_tlb(tlb, pudp, addr) __pud_free_tlb(tlb, pudp, addr)
+
+#define pmd_free_tlb(tlb, pmdp, addr) __pmd_free_tlb(tlb, pmdp, addr)
+
+#define tlb_migrate_finish(mm) do {} while (0)
+
+#endif
-- 
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