1 files changed, 96 insertions, 0 deletions
diff --git a/arch/hexagon/include/asm/pgalloc.h b/arch/hexagon/include/asm/pgalloc.h
new file mode 100644
index 0000000000..55988625e6
--- /dev/null
+++ b/arch/hexagon/include/asm/pgalloc.h
@@ -0,0 +1,96 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Page table support for the Hexagon architecture
+ *
+ * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
+ */
+
+#ifndef _ASM_PGALLOC_H
+#define _ASM_PGALLOC_H
+
+#include <asm/mem-layout.h>
+#include <asm/atomic.h>
+
+#include <asm-generic/pgalloc.h>
+
+extern unsigned long long kmap_generation;
+
+/*
+ * Page table creation interface
+ */
+static inline pgd_t *pgd_alloc(struct mm_struct *mm)
+{
+	pgd_t *pgd;
+
+	pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
+
+	/*
+	 * There may be better ways to do this, but to ensure
+	 * that new address spaces always contain the kernel
+	 * base mapping, and to ensure that the user area is
+	 * initially marked invalid, initialize the new map
+	 * map with a copy of the kernel's persistent map.
+	 */
+
+	memcpy(pgd, swapper_pg_dir, PTRS_PER_PGD*sizeof(pgd_t));
+	mm->context.generation = kmap_generation;
+
+	/* Physical version is what is passed to virtual machine on switch */
+	mm->context.ptbase = __pa(pgd);
+
+	return pgd;
+}
+
+static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
+				pgtable_t pte)
+{
+	/*
+	 * Conveniently, zero in 3 LSB means indirect 4K page table.
+	 * Not so convenient when you're trying to vary the page size.
+	 */
+	set_pmd(pmd, __pmd(((unsigned long)page_to_pfn(pte) << PAGE_SHIFT) |
+		HEXAGON_L1_PTE_SIZE));
+}
+
+/*
+ * Other architectures seem to have ways of making all processes
+ * share the same pmd's for their kernel mappings, but the v0.3
+ * Hexagon VM spec has a "monolithic" L1 table for user and kernel
+ * segments.  We track "generations" of the kernel map to minimize
+ * overhead, and update the "slave" copies of the kernel mappings
+ * as part of switch_mm.  However, we still need to update the
+ * kernel map of the active thread who's calling pmd_populate_kernel...
+ */
+static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd,
+				       pte_t *pte)
+{
+	extern spinlock_t kmap_gen_lock;
+	pmd_t *ppmd;
+	int pmdindex;
+
+	spin_lock(&kmap_gen_lock);
+	kmap_generation++;
+	mm->context.generation = kmap_generation;
+	current->active_mm->context.generation = kmap_generation;
+	spin_unlock(&kmap_gen_lock);
+
+	set_pmd(pmd, __pmd(((unsigned long)__pa(pte)) | HEXAGON_L1_PTE_SIZE));
+
+	/*
+	 * Now the "slave" copy of the current thread.
+	 * This is pointer arithmetic, not byte addresses!
+	 */
+	pmdindex = (pgd_t *)pmd - mm->pgd;
+	ppmd = (pmd_t *)current->active_mm->pgd + pmdindex;
+	set_pmd(ppmd, __pmd(((unsigned long)__pa(pte)) | HEXAGON_L1_PTE_SIZE));
+	if (pmdindex > max_kernel_seg)
+		max_kernel_seg = pmdindex;
+}
+
+#define __pte_free_tlb(tlb, pte, addr)				\
+do {								\
+	pagetable_pte_dtor((page_ptdesc(pte)));			\
+	tlb_remove_page_ptdesc((tlb), (page_ptdesc(pte)));	\
+} while (0)
+
+#endif